LED行业分析论文 英文
led节能灯的原理中学生英语作文
LED节能灯的原理In the modern world of technology, energy-efficient lighting solutions have become increasingly important. Among these solutions, LED (Light Emitting Diode) lighting has emerged as a highly effective and environmentally friendly alternative to traditional incandescent and fluorescent lights. The principle behind LED lighting and its advantages, especially in the context of energy conservation, are worth exploring for middle school students.**The Basic Principle of LEDs**LEDs work on the principle of electroluminescence, a process where light is emitted when an electric current passes through a material. Unlike incandescent bulbs, which generate light by heating a filament to a high temperature, LEDs convert electrical energy directly into light. This conversion is highly efficient, with very little energylost as heat.The heart of an LED is a semiconductor material, typically made up of compounds like gallium arsenide,gallium phosphide, or indium gallium nitride. These semiconductors have a unique property: when a voltage is applied across them, they emit light. The color of the emitted light depends on the material used.**How LEDs Save Energy**LEDs are extremely efficient at converting electricity into light. While incandescent bulbs convert only about 10% of the electrical energy they use into light, with the rest being lost as heat, LEDs can convert up to 90% of the energy they consume into light. This means that LEDs use much less electricity to produce the same amount of light as incandescent bulbs, leading to significant energy savings.Furthermore, LEDs last much longer than traditional light sources. Incandescent bulbs typically last for around 1,000 hours, while LEDs can last for up to 50,000 hours. This long lifespan not only reduces the frequency of bulb replacements, but also saves on maintenance costs.**Applications of LEDs**LEDs are finding their way into a wide range of applications, from home lighting to traffic signals and even automotive headlights. In the home, LED bulbs are now available in a variety of shapes and sizes, suitable for different fixtures and uses. They can be dimmed just like incandescent bulbs, and come in warm white and other colors to create the perfect atmosphere.**Conclusion**LEDs represent a significant advancement in lighting technology, offering both energy efficiency and longevity. As middle school students, it's important to understand the principles behind this innovative lighting solution and its role in promoting sustainable living. By switching to LED lighting, we can reduce our energy consumption, save money, and contribute to a greener, more sustainable future.**LED节能灯的原理**在现代科技世界中，节能照明解决方案变得越来越重要。
led节能灯的原理英语作文
led节能灯的原理英语作文Light-emitting diodes, commonly known as LEDs, are the cornerstone of modern lighting systems. Unlike traditional incandescent bulbs, which generate light through the heating of a filament, LEDs create light through a process called electroluminescence. This process involves the movement of electrons within a semiconductor material, typically composed of elements like gallium, arsenic, and phosphorus.When an electric current passes through the semiconductor, electrons are excited to a higher energy state. As these electrons return to their original state, they release energy in the form of photons, which we perceive as light. The specific materials used in the semiconductor determine the color of the light emitted, which can range across the visible spectrum, as well as ultraviolet and infrared.The efficiency of LEDs is unparalleled when compared to traditional lighting methods. Incandescent bulbs, for example, convert only about 10% of the energy they consume into light, with the rest lost as heat. LEDs, on the other hand, can convert up to 90% of their energy into light, making them significantly more energy-efficient and cost-effective over time.Moreover, LEDs have a much longer lifespan. While an average incandescent bulb may last for about 1,000 hours, an LED can last for up to 50,000 hours or more. This longevity reduces the need for frequent replacements, further contributing to their cost-effectiveness and reducing the environmental impact associated with the production and disposal of lighting components.Another advantage of LED lighting is its versatility. LEDs can be designed to produce a wide range of light intensities and colors, and they can be dimmed to suit various atmospheres and preferences. This flexibility makes them suitable for a vast array of applications, from household lighting to electronic displays and medical devices.LEDs also contribute to environmental conservation. Their low power consumption translates to a reduced demand for electricity, which can lead to a decrease in greenhousegas emissions from power plants. Additionally, LEDs do not contain hazardous substances like mercury, which is present in compact fluorescent lamps (CFLs), making them safer to handle and recycle.In conclusion, the principle of LED lighting represents a significant advancement in technology and sustainability. Through the innovative use of semiconductor materials, LEDs provide a highly efficient, durable, and versatile lighting solution that benefits both consumers and the environment. As the world continues to seek greener alternatives, the role of LED lighting in energy conservation and environmental protection becomes increasingly important, shining a light on a brighter, more sustainable future. 。
led灯的原理是什么英语作文
led灯的原理是什么英语作文LEDs, or Light Emitting Diodes, are a marvel of modern technology. They work on the principle of electroluminescence, where electrical energy is converted directly into light.At the heart of an LED is a semiconductor material, typically made of gallium arsenide or silicon carbide. When a current passes through this material, electrons recombinewith electron holes, releasing energy in the form of photons.This process is highly efficient, with LEDs consumingless power than incandescent bulbs. They also have a longer lifespan, making them a popular choice for various lighting applications.One of the key advantages of LEDs is their ability toemit light in a specific color. This is because the energy bandgap of the semiconductor material can be adjusted to produce different wavelengths of light.Furthermore, LEDs are environmentally friendly. They donot contain harmful substances like mercury, which is foundin fluorescent lights. They also generate less heat, reducing energy waste.In recent years, advancements in LED technology have ledto the development of smart lighting systems. These systems can be controlled remotely, adjusting brightness and color tosuit different environments and moods.Overall, the principle behind LEDs is a testament to the ingenuity of human innovation. As we continue to explore new applications for this technology, the future of lighting is looking brighter than ever.。
led节能灯的原理英语作文
led节能灯的原理英语作文英文回答：Principles of LED Energy-Efficient Lighting.LED (light-emitting diode) energy-efficient lighting relies on a unique operating principle compared to traditional incandescent or fluorescent lighting. Here's how LEDs work:1. Semiconductor Materials: LEDs are based on semiconductor materials, such as gallium nitride (GaN), indium gallium nitride (InGaN), or aluminum gallium arsenide (AlGaAs). These materials have a unique electronic structure that allows them to emit light when an electric current passes through them.2. P-N Junction: Inside an LED, there are two semiconductor layers with opposite electrical charges: a p-type layer (with positively charged holes) and an n-typelayer (with negatively charged electrons). When a voltage is applied to the LED, the electrons and holes areattracted to each other.3. Light Emission: As the electrons and holes meet at the p-n junction, they recombine and release energy in the form of photons. The wavelength of these photons determines the color of light emitted.4. Energy Efficiency: LEDs are highly energy-efficient because most of the electrical energy they consume is converted into light, with minimal heat loss. This is in contrast to incandescent bulbs, which lose a significant portion of their energy as heat.5. Long Lifespan: LEDs have a very long lifespan, typically lasting between 50,000 to 100,000 hours of continuous use. This greatly exceeds the lifespan of incandescent bulbs (1,000-2,000 hours) and fluorescent bulbs (6,000-15,000 hours).6. Compact Size and Dimmability: LEDs are extremelycompact and can be easily incorporated into various lighting fixtures and devices. They are also dimmable, allowing for adjustable light output.中文回答：LED节能灯的工作原理。
led行业英文论文
3.4 How does the pclusion
5.0 references
1.0 Introduction
1.1 Industry
1.2 company
The consumer lighting industry is acontinuousof new-product innovation. In recent yeas new technology has enabled the consumer lighting manufacturer todevelopvarious new Lighting source, in particular, LED lighting is gradually becoming new core of lighting market.In fact it seems like there is a new lighting source launched in lighting field with high-brightness, low-energy consumption and long-life span. LED lighting, as new-product market, has appeared so attractive that most traditional lighting manufacturers have been taking part in this new competition of lighting at this stage, Such as PHILIP and SIEMENS and so on, all these famous electrical companies put more investment into research and develop relative LED new products to take possession of global lighting market, because many lighting marketers and lighting technicians realize that LED lighting will become main lighting products in the future.
led 英文作文
led 英文作文Title: The Illuminating Evolution of LED Technology。
In the realm of lighting technology, Light Emitting Diodes (LEDs) stand out as a beacon of innovation, revolutionizing how we illuminate our world. From humble beginnings to omnipresent applications, the journey of LEDs exemplifies the remarkable progression of technology. This essay explores the history, principles, applications, and future prospects of LED technology.LEDs trace their origins back to the early 20th century when H.J. Round discovered electroluminescence in 1907. However, it wasn't until 1962 that Nick Holonyak Jr. developed the first practical visible-spectrum LED at General Electric. This breakthrough paved the way for further advancements, leading to the development of high-brightness LEDs in the 1990s, capable of producing intense light efficiently.At the heart of LED technology lies the principle of electroluminescence, where a semiconductor material emits light in response to the passage of an electric current. Unlike traditional incandescent bulbs, which rely on heating a filament to produce light, LEDs operate through a process that involves the movement of electrons within a semiconductor structure.The advantages of LEDs over conventional lighting sources are manifold. Firstly, LEDs are highly energy-efficient, converting a larger portion of electrical energy into visible light compared to incandescent or fluorescent bulbs. This efficiency translates to reduced energy consumption and lower electricity bills, making LEDs an environmentally friendly lighting option.Secondly, LEDs boast a longer lifespan, typically lasting tens of thousands of hours compared to therelatively short lifespan of incandescent bulbs. This longevity not only reduces maintenance costs but also minimizes the frequency of bulb replacements, contributing to resource conservation and waste reduction.Furthermore, LEDs offer unparalleled versatility in terms of design and application. Their small size and low profile enable their integration into compact devices and architectural elements, facilitating innovative lighting designs in various contexts, including residential, commercial, automotive, and outdoor lighting.The widespread adoption of LEDs across diverse sectors has catalyzed transformative changes in numerous industries. In the realm of display technology, LEDs have enabled the development of high-definition, energy-efficient displaysfor televisions, monitors, and digital signage, revolutionizing visual communication and entertainment experiences.In the automotive industry, LEDs have become ubiquitous in vehicle lighting systems, offering superior brightness, efficiency, and durability compared to traditional halogenor xenon headlights. LED headlights not only enhancevisibility for drivers but also contribute to enhancedsafety on the roads.Moreover, LEDs have found applications in horticulture as grow lights, enabling precise control over light spectrum and intensity to optimize plant growth and yieldin indoor farming environments. This application underscores the transformative potential of LEDs in addressing global food security challenges.Looking ahead, the future of LED technology promises even greater advancements and innovations. Researchers are exploring novel materials and fabrication techniques to enhance the efficiency, brightness, and color-rendering capabilities of LEDs. Additionally, the integration of smart controls and connectivity features will enable the development of intelligent lighting systems that adapt to environmental conditions and user preferences, further optimizing energy usage and enhancing user experience.In conclusion, the evolution of LED technology embodies the relentless pursuit of efficiency, sustainability, and innovation in the field of lighting. From its humble beginnings to its pervasive presence in our daily lives,LEDs have illuminated the path towards a brighter, more energy-efficient future. As we continue to harness the potential of LED technology, we embark on a journey towards a more illuminated and sustainable world.。
led作文
led作文英文回答：The Allure of LEDs。
Light-emitting diodes (LEDs) have emerged as a revolutionary lighting technology, transforming the way we illuminate our surroundings. These miniature semiconductor devices produce light when an electric current passes through them, emitting a vibrant and energy-efficient glow. Unlike traditional incandescent bulbs, LEDs do not rely on a heated filament to generate light, making them far more efficient and durable.LEDs have numerous advantages over other lighting sources. They boast exceptional energy efficiency, consuming up to 90% less energy than incandescent bulbs and 50% less than fluorescent lights. This energy savings translates into significant cost reductions over time, reducing utility bills and contributing to environmentalsustainability.Furthermore, LEDs offer a remarkably long lifespan, lasting up to 50,000 hours or more. This exceptional durability eliminates the frequent bulb replacements associated with incandescent and fluorescent lighting, reducing maintenance costs and minimizing the hassle of replacing burned-out bulbs.Another key advantage of LEDs is their versatility. These devices can be used in a wide range of applications, from home lighting to commercial signage, automotive headlights to traffic signals. Their compact size and low heat output make them ideal for use in tight spaces and sensitive environments.In terms of color quality, LEDs excel over traditional light sources. They provide a broad spectrum of colors with exceptional accuracy, making them ideal for applications where color fidelity is crucial, such as in retail displays and museums.While the initial cost of LEDs can be higher than thatof traditional bulbs, their long lifespan and energy efficiency make them a cost-effective investment over time. As LED technology continues to advance, the cost of these devices is expected to further decline, making them even more accessible to consumers.中文回答：LED 的魅力。
关于led灯的英语作文1000字
关于led灯的英语作文1000字The Evolution and Impact of LED Lighting.In the rapidly advancing world of technology, LED (Light Emitting Diode) lighting has emerged as a revolutionary force, transforming the way we perceive and utilize lighting. Its journey from a mere electronic component to a global phenomenon illustrates the power of innovation and continuous research.LEDs, first discovered in the 1960s, were initially used as indicator lights in electronic devices due to their small size and low power consumption. However, it wasn't until the 21st century that LEDs truly began to shine, thanks to advancements in materials science and manufacturing techniques. This allowed for the creation of high-brightness LEDs that were not only more energy-efficient but also offered a wide range of colors and adjustable brightness levels.The shift from traditional incandescent and fluorescent lighting to LEDs has been nothing short of remarkable. LEDs offer several advantages that make them ideal for a wide range of applications. Firstly, they consume significantly less power, resulting in lower energy bills and reduced carbon emissions. Secondly, LEDs have a longer lifespan, lasting up to 50 times longer than incandescent bulbs, which means less frequent replacements and reduced waste. Lastly, LEDs provide excellent color rendering and can be dimmed without affecting their lifespan or color temperature, offering greater flexibility and control.The impact of LEDs on various industries cannot be overstated. In the architecture and design sector, LEDs have enabled the creation of stunning, energy-efficient lighting solutions that enhance the aesthetics of buildings and spaces. From the vibrant displays of neon signs to the subtle ambient lighting of modern homes, LEDs have provided designers with unprecedented creative freedom.In the automotive industry, LEDs have revolutionized exterior and interior lighting. They are now used inheadlights, taillights, and even as interior ambient lighting, adding a touch of luxury and style to vehicles. The bright, crisp light emitted by LEDs improves visibility and safety on the road.The agricultural industry has also benefited from the adoption of LEDs. Grow lights, powered by LEDs, have allowed farmers to extend the growing season, increase crop yields, and even cultivate crops in environments where natural sunlight is limited. LEDs emit specific wavelengths of light that promote photosynthesis, resulting inhealthier and more vigorous plants.Moreover, LEDs have found their way into our dailylives in the form of indicator lights, displays, and backlighting in electronic devices such as smartphones, televisions, and computers. They have become an integral part of our digital world, enhancing the user experience with their bright, crisp, and energy-efficient lighting.However, the rise of LEDs has not been without its challenges. The initial high cost of LEDs compared totraditional lighting solutions has been a barrier to widespread adoption in some sectors. Furthermore, the disposal of used LEDs can pose an environmental challenge if not handled properly.Nevertheless, as technology continues to advance, the cost of LEDs is expected to decrease further, making them more accessible to a wider range of applications. At the same time, efforts are being made to develop more sustainable manufacturing processes and recycling methods to minimize the environmental impact of LEDs.In conclusion, the journey of LEDs from a simple electronic component to a global phenomenon has been remarkable. Their transformative impact on various industries and our daily lives is a testament to the power of innovation and continuous research. As we move forward, LEDs will continue to revolutionize the way we perceive and utilize lighting, driving further advancements in energy efficiency, sustainability, and design.。
led照明毕业论文中英文资料外文翻译文献
led照明毕业论文中英文资料外文翻译文献Renewable and Sustainable Energy ReviewsHigh-brightness LEDs—Energy efficient lighting sources and their potential in indoor plant cultivation ABSTRACTThe rapid development of optoelectronic technology since mid-1980 has significantly enhanced the brightness and efficiency of light-emitting diodes (LEDs). LEDs have long been proposed as a primary light source for space-based plant research chamber or bioregenerative life support systems. The raising cost of energy also makes the use of LEDs in commercial crop culture imminent. With their energy efficiency, LEDs have opened new perspectives for optimizing the energy conversion and the nutrient supply both on and off Earth. The potentials of LED as an effective light source for indoor agriculturalproduction have been explored to a great extent. There are many researches that use LEDs to support plant growth in controlled environments such as plant tissue culture room and growth chamber. This paper provides a brief development history of LEDs and a broad base review on LED applications in indoor plant cultivation since 1990.Contents1. Introduction2. LED development.3. Color ratios and photosynthesis4. LEDs and indoor plant cultivation.4.1. Plant tissue culture and growth4.2. Space agriculture84.3. Algaculture4.4. Plant disease reduction5. Intermittent and photoperiod lighting and energy saving6. Conclusion1. IntroductionWith impacts of climate change, issues such as more frequent and seriousdroughts, floods, and storms as well as pest and diseases are becoming more serious threats to agriculture. These threats along with shortage of food supply make people turn to indoor and urban farming (such as vertical farming) for help. With proper lighting, indoor agriculture eliminates weather-related crop failures due to droughts and floods to provide year-round crop production, which assist in supplying food in cities with surging populations and in areas of severe environmental conditions.The use of light-emitting diodes marks great advancements over existing indoor agricultural lighting. LEDs allow the control of spectral composition and the adjustment of light intensity to simulate the changes of sunlight intensity during the day. They have the ability to produce high light levels with low radiant heat output and maintain useful light output for years. LEDs do not contain electrodes and thus do not burn out like incandescent or fluorescent bulbs that must be periodically replaced. Not to mention that incandescent and fluorescent lamps consume a lot of electrical power while generating heat, which must be dispelled from closed environments such as spaceships and space stations.2. LED developmentLED is a unique type of semiconductor diode. It consists of a chip of semiconductor material doped with impurities to create a p–n junction. Current flows easily from the p-side (anode), to the n-side (cathode), but not in the reverse direction.Electrons and holes flow into the junction from electrodes with different voltages. When an electron meets a hole, it falls into a lower energy level, and releases energy in the form of a photon. The color (wavelength) of the light emitted depends on the band gap energy of the materials forming the p–n junction. The materials used for an LED have a direct band gap with energies corresponding to near-infrared, visible or near-ultraviolet light.The key structure of an LED consists of the die (or light-emitting semiconductor material), a lead frame where the die is placed, and the encapsulation which protects the die (Fig. 1).Fig.1LED development began with infrared and red devices made with gallium arsenide. Advances in materials science have made possible the production of devices with ever-shorter wavelengths, producing light in a variety of colors. J.Margolin reported that the first known light-emitting solid state diode was made in 1907 by H. J. Round. No practical use of Round’s diode was made for several decades until the invention of the first practical LED by Nick Holonyak, Jr in 1962. His LEDs became commercially available inlate 1960s. These GaAsP LEDs combine three primary elements: gallium, arsenic and phosphorus to provide a 655nm red light with brightness levels of approximately 1–10 mcd at 20mA. As the luminous intensity was low, these LEDs were only used in a few applications, primarily as indicators. Following GaAsP, GaP (gallium phosphide) red LEDs were developed. These device sex hibit very high quantum efficiencies at low currents. As LED technology progressed through the 1970s, additional colors and wavelengths became available. The most common materials were GaP green and red, GaAsP orange, and high efficiency red and GaAsP yellow. The trend towards more practical applications (such as in calculators, digital watches, and test equipment) also began to develop. As the LED materials technology became more advanced, the light output was increased, and LEDs became bright enough to be used for illumination.In 1980s a new material, GaAlAs (gallium aluminum arsenide) was developed followed by a rapid growth in the use of LEDs. GaAlAs technology provides superiorperformance over previously available LEDs. The voltage requirement is lower, which results in a total power savings. LEDs could be easily pulsed or multiplexed and thus are suitable for variable message and outdoor signs. Along this development period, LEDs were also designed into bar code scanners, fiber optic data transmission systems, and medicalequipment. During this time, the improvements in crystal growth and optics design allow yellow, green and orange LEDs only a minor improvement in brightness and efficiency. The basic structure of the material remained relatively unchanged.As laser diodes with output in the visible spectrum started to commercialize in late 1980s, LED designers used similar techniques to produce high-brightness and high reliability LEDs. This led to the development of InGaAlP (indium gallium aluminum phosphide) visible light LEDs. Via adjusting the energy band gap InGaAlP material can have different color output. Thus, green, yellow, orange and red LEDs could all be produced using the same basic technology. Also, light output degradation of InGaAlP material is significantly improved.Shuji Nakamura at Nichia Chemical Industries of Japan introduced blue LEDs in 1993. Blue LEDs have always been difficult to manufacture because of their high photon energies (>2.5 eV) and relatively low eye sensitivity. Also, the technology to fabricate these LEDs is very different and less advanced than standard LED materials. But blue is one of the primary colors (the other two being red and green). Properly combining the red, green, and blue light is essential to produce white and full-color. This process requires sophisticated software and hardware design to implement. In addition, the brightness level is low and the overall light output of each RGB die being used degrades at a different rate resulting in an eventual color unbalance. The blue LEDs available today consist of GaN (gallium nitride) and SiC (silicon carbide) construction. The blue LED that becomes available in production quantities has result in an entire generation of new applications that include telecommunications products, automotive applications, traffic control devices, and full-color message boards. Even LED TVs can soon become commercially available.Compare to incandescent light’s 1000-h and fluorescent light’s 8000-h life span, LEDs have a very significantly longer life of 100,000 h. In addition to their long life, LEDs have many advantages over conventional light source. These advantages include small size, specific wavelength, low thermal output, adjustable light intensity and quality, as well as high photoelectric conversion efficiency. Such advantages make LEDs perfect for supporting plant growth in controlled environment such as plant tissue culture room and growth chamber. Table 1 is a list of some common types of LEDs as compiled from .The chlorophyll molecules in plants initiate photosynthesis bycapturing light energy and converting it into chemical energy to help transforming water and carbon dioxide into the primary nutrient for living beings. The generalized equation for the photosynthetic process is given as:CO2 + H2O—light—>（CH2O）+ O2where (CH2O) is the chemical energy building block for thesynthesis of plant components.Chlorophyll molecules absorb blue and red wavelengths most efficiently. The green and yellow wavelengths are reflected or transmitted and thus are not as important in the photosyntheticprocess. That means limit the amount of color given to the plants and still have them grow as well as with white light. So, there is no need to devote energy to green light when energy costs are aconcern, which is usually the case in space travel.The LEDs enable researchers to eliminate other wavelengths found within normal white light, thus reducing the amount of energy required to power the plant growth lamps. The plants grow normally and taste the same as those raised in white light.Red and blue light best drive photosynthetic metabolism. These light qualities are particularly efficient in improving the developmental characteristics associated with autotrophic growth habits. Nevertheless, photosynthetically inefficient light qualities also convey important environmental information to a developing plant. For example, far-red light reverses the effect of phytochromes, leading to changes in gene expression, plant architecture, and reproductive responses. In addition, photoperiod (the adjustment of light and dark periods) and light quality (the adjustment of red, blue and far-red light ratio) also have decisive impacts on photomorphogenesis.The superimposed pattern of luminescence spectrum of blue LED (450–470 nm) and that of red LED (650–665 nm) corresponds well to light absorption spectrum of carotenoids and chlorophyll. Various plant cultivation experiments are possible when these twokinds of LED are used with the addition of far-red radiation (730–735 nm) as the light source. Along the line of the LED technology advancement, LEDs become a prominent light source for intensive plant culture systems and photobiological researches. The cultivation experiments which use such light sources are becoming increasingly active. Plant physiology and plant cultivation researches using LEDs started to peak in 1990s and become inevitable in the new millennium. Those researches have confirmed that LEDs are suitable for cultivation of a variety of algae,crop, flower, fruit, and vegetable.Some of the pioneering researches are reviewed in the followings.Bula et al. have shown that growing lettuce with red LEDs in combination with blue tubular fluorescent lamp (TFL) is possible. Hoenecke et al. have verified the necessity of blue photons for lettuce seedlings production by using red LEDs with blue TFL. As the price of both blue and red LEDs have dropped and the brightness increased significantly, the research findings have been able to be applied in commercial production. As reported by Agence France Press, Cosmo Plant Co., in Fukuroi, Japan has developed a red LED-based growth process that uses only 60% of electricity than a fluorescent lighting based one.Tennessen et al. have compared photosynthesis from leaves of kudzu (Pueraria lobata) enclosed in a leaf chamber illuminated by LEDs versus by a xenon arc lamp. The responses of photosynthesis to CO2 are similar under the LED and xenon arc lamps at equal photosynthetic irradiance. There is no statistical significant difference between the white light and red light measurements in high CO2. Some leaves exhibited feedback inhibition of photosynthesis which is equally evident under irradiation of either lamp type. The results suggest that photosynthesis research including electron transport, carbon metabolismand trace gas emission studies should benefit greatly from the increased reliability, repeatability and portability of a photosynthesis lamp based on LEDs.Okamoto et al. have investigated the effects of different ratios of red and blue (red/blue) photosynthetic photon flux density (PPFD) levels on the growth and morphogenesis of lettuce seedlings. They have found that the lettuce stem length decreases significantly with an increase in the blue PPFD. The research has also identified the respective PPFD ratio that (1) accelerates lettuce seedlings’stem elongation, (2) maximizes the whole plant dry weight, (3) accelerates the growth of whole plants, and (4) maximizes the dry weights of roots and stems. Photosynthesis does not need to take place in continuous light. The solid state nature allows LEDs to produce sufficient photon fluxes and can be turned fully on and off rapidly (200 ns), which is not easily achievable with other light sources. This rapid on–off feature has made LEDs an excellent light source for photosynthesis research such as pulsed lighting for the study of photosynthetic electron transport details. The off/dark period means additional energy saving on top of the LEDs’low power consumption.4. LEDs and indoor plant cultivation4.1. Plant tissue culture and growthTissue culture (TC), used widely in plant science and a number of commercial applications, is the growth of plant tissues or cells within a controlled environment, an ideal growth environment that is free from the contamination of microorganisms and other contaminants. A controlled environment for PTC usually means filtered air, steady temperature, stable light sources, and specially formulated growth media (such as broth or agar). Micropropagation, a form of plant tissue culture (PTC), is used widely in forestry and floriculture. It is also used for conserving rare or endangered plant species. Other uses of PTC include:1short-term testing of genetic constructions or regeneration oftrans genic plants,2 cross breeding distantly related species and regeneration of the novel hybrid,3 screening cells for advantageous characters (e.g. herbicidere sistance/tolerance),4embryo rescue (i.e. to cross-pollinate distantly related specie sand then tissue culture there sulting embryo which would normally die),5 large-scale growth of plant cells in liquid culture inside bioreactors as a source of secondary products (like recombinant proteins used as biopharmaceuticals).6production of doubled monoploid plants from haploid cultures to achieve homozygous lines more rapidly in breeding programs (usually by treatment with colchicine which causes doubling of the chromosome number).Tissue culture and growth room industries have long been using artificial light sources for production. These light sources include TFL, high pressure sodium lamp (HPS), metal halide lamp (MHL) and incandescent lamp, etc. Among them, TFL has been the most popular in tissue culture and growth room industries. However, the use of TFL consumes 65% of the total electricity in a tissue culture lab. That is the highest non-labor costs. As a result, these industries continuously seek for more efficient light sources. The development of high-brightness LED has made LED a promising light source for plant growth in controlled environments.Nhut et al. have cultured strawberry plantlets under different blue to red LED ratios as well as irradiation levels and compared its growth to that under plant growth fluorescent. The results suggest that a culture system using LED is advantageous for the micropropagation of strawberry plantlets. The study also demonstrates that the LED light source for in vitro culture of plantlets contributes to an improved growth of the plants in acclimatization.Brown et al. have measured the growth and dry matter partitioning of ‘Hungarian Wax’pepper (Capsicum annuum L.) plants grown under red LEDs compared with similar plants grown under red LEDs with supplemental blue or far-red radiation. Pepper biomass reduces when grown under red LEDs without blue wavelengths compared to plants grown under supplemental blue fluorescent lamps. The addition of far-red radiation results in taller plants with greater stem mass than red LEDs alone. Fewer leaves developed under red or red plus far-red radiation than with lamps producing blue wavelengths. The results of their research indicate that with proper combination of other wavelengths, red LEDs may be suitable for the culture of plants in tightly controlled environments.4.2. Space agricultureBecause re-supply is not an option, plants are the only options to generate enough food, water and oxygen to help make future explorers self-sufficient at space colonies on the moon, Mars or beyond. In order to use plants, there must be a light source. Standard light sources that used in homes and in greenhouses and in growth chambers for controlled agriculture here on Earth are not efficient enough for space travel. While a human expedition outside Earth orbit still might be years away, the space farming efforts are aimed at developing promising artificial light sources. LEDs, because of their safety, small mass and volume, wavelength specificity, and longevity, have long been proposed as a primary light source for space-base plant research chamber or bioregenerative life support systems .Infrared LEDs that are used in remote controls devices have other uses. Johnson et al. have irradiated oat (Avena sativa cv Seger) seedlings with infrared (IR) LED radiation passed through a visible-light-blocking filter. The irradiated seedlings exhibited differences in growth and gravitropic response when compared to seedlings grown in darkness at the same temperature. This suggests that the oat seedlings are able to detect IR LED radiation. These findings also expand the defined range of wavelengths involved in radiation–gravity (light–gravity) interactions to include wavelengths in the IR region of the spectrum.Goins et al. grow wheat under red LEDs and compare them to the wheat grown under (1) white fluorescent lamps and (2) red LEDs supplemented with blue light from blue fluorescent lamps. The results show that wheat grown under red LEDs alone displayed fewer subtillers and a lower seed yield compared to those grown under white light. Wheat grown under red LEDs + 10% BF light had comparable shoot dry matter accumulation and seed yield relative to those grown under white light. These results indicate that wheat can complete its life cycle under red LEDs alone, but larger plants and greater amounts of seed are produced in the presence of red LEDs supplemented with a quantity of blue light.The research of Goins and his team continues in plant growth chambers the size of walk-in refrigerators with blue and red LEDs to grow salad plants such as lettuce and radishes. They hope the plant growth chamber would enable space station staff to grow and harvest salad greens, herbs and vegetables during typical fourmonth tours on the outpost .4.3. AlgacultureAlgaculture, refers to the farming of species of algae, has been a great source for feedstock, bioplastics, pharmaceuticals, algae fuel, pollution control, as well as dyes and colorants. Algaculture also provides hopeful future food sources.Algae can be grown in a photobioreactor (PBR), a bioreactor which incorporates some type of light source. A PBR is a closed system, as opposed to an open tank or pond. All essential nutrients must be introduced into the system to allow algae to grow and be cultivated. A PBR extends the growing season and allows growing more species. The device also allows the chosen species to stay dominant. A PBR can either be operated in ‘‘batch mode’’or ‘‘continuous mode’’in which a continuous stream of sterilized water that contains air, nutrients, and carbon dioxide is introduced. As the algae grows, excess culture overflows and is harvested.When the algae grow and multiply, they become so dense that they block light from reaching deeper into the water. As a result, light only penetrates the top 7–10 cm of the water in most algalcultivation systems. Algae only need about 1/10 the amount of direct sunlight. So, direct sunlight is often too strong for algae. A means of supplying light to algae at the right concentration is to place the light source in the system directly.Matthijs et al. have used LEDs as the sole light source in continuous culture of the green alga (Chlorella pyrenoidosa). The research found the light output of the LED panel in continuous operation sufficient to support maximal growth. Flash operation at 5-ps pulse ‘‘on’’ duration between dark periods of up to 45 ps would stillsustain near maximum growth. While longer dark periods tend to cut the growth rate, the light flux decrease resulting from such operation does not reduce the growth as much as that of the similar flux decrease in continuous operation. Their research concludes that the use of flashing LEDs (which means intermittent light) in indoor algal culture yielded a major gain in energy economy comparing to fluorescent light sources. An additional advantage is that heat waste losses are much smaller. The most interesting discovery of this study may be that adding blue light to the red LED light did not change the growth properties.In order to take advantage of the biotechnological potential of algae, Lee and Palsson have calculated theoretical values of gas mass transfer requirements and light intensity requirements to support high-density algal cultures for the 680 nm monochromatic red light from LED as a light source. They have also designed a prototype PBR based on these calculations. Using on-line ultra filtration to periodically provide fresh medium, these researchers have achieved a cell concentration of more than 2×109cells/ml (more than 6.6%, vol/vol), cell doubling times as low as 12 h, and an oxygen production rate as high as 10 mmol oxygen/l culture/h. This research indicates that the development of a small LED-based algal photobioreactors is economically achievable.Another research of algae via LEDs is conducted by Nedbal et al. Their research is a study of light fluctuation effects on a variety of algae in dilute cultures using arrays of red LEDs to provide intermittent and equivalent continuous light in small-size (30 ml) bioreactors. The results endorse that the algae growth rates in certain calculated intermittent light can be higher than the growth rate in the equivalent continuous light. Yanagi and Okamoto has grown five spinach plants under the red LEDs and another five under 40W plant growth fluorescent lamps at the same light intensity of 125 mmol/m2/s. The dry matter production under the LEDs is slightly less than that under the fluorescent lamps. The plant leaf area under the red LEDs is also smaller than that under the fluorescent lamps. Nevertheless, they reach a conclusion that LEDs can qualify as an artificial light source for plant growth.4.4.Plant disease reductionSchuerger and Brown have used LED arrays with different spectral qualities to determine the effects of light on the development of tomato mosaic virus (ToMV) in peppers and powdery mildew on cucumbers. Their research concludes that spectral quality may alter plant disease development. Latter research regarding bacterial wilt on tomato has confirmed this conclusion and demonstrates that spectral quality may be useful as a component of an integrated pest management program for space-based ecological life support systems. Schuerger et al. have shown that the spectral quality effects on peppers’ anatomical changes in stem and leaf tissues are corr elated to the amount of blue light in primary light source.Miyashita et al. use red LEDs (peak wavelength: 660 nm) and white fluorescent lamps as light sources for potato plantlets growth in vitro. They found that shoot length and chlorophyll concentration of the plantlets increases with increasing 630–690 nm red photon flux (R-PF) while there are no significant differences in dry weight and leaf area of the plantlets with different R-PF levels. This means red lightaffects the morphology rather than the growth rate of potato plantlets in vitro. As a result, they suggest that red LEDs can be used for controlling plantlet morphology in micropropagation.5. Intermittent and photoperiod lighting and energy savingTime constants for photosynthetic processes can be divided into three ranges: primary photochemistry, electron shuttling, and carbon metabolism. These three photosynthetic processes can be uncoupled by providing pulses of light within the appropriate range for each process. At high frequencies, pulsing light treatments can be used to separate the light reactions (light harvesting and charge separation) from the dark reactions (electron shuttling) of photosynthetic electron transport. LEDs’ flexible pulsating ability can be coupled with such characteristics of photosynthesis and lead to additional energy saving.Tennessen et al. use LEDs to study the effects of light pulses (micro- to milli-second) of intact tomato leaves. They found that when the equivalent of 50 mmol photons mp -2s-1 is provided during 1.5 ms pulses of 5000 mmol photons mp -2s-1 followed by 148.5 ms dark periods, photosynthesis is the same as in continuous 50 mmol photons mp -2s-1 . Data support the theory that photons in pulses of 100 ps or shorter are absorbed and stored in the reaction centers to be used in electron transport during the dark period. Pigments of the xanthophyll cycle were not affected by pulsed light treatments. This research suggests that, instead of continuous light, using effectively calculated intermittent light (which means less energy consumption) might not affect the plant production.Jao and Fang have investigated the effects of intermittent light on growth of potato plantlets in vitro. They also use conventional TFLs for the experiment to explore the electrical savings realized by adjusting the frequency and duty ratio of LEDs. TFLs provide continuous fluctuating light at 60 Hz while LEDs provide nonfluctuating light and pulse light of the preset frequency and duty ratio. When the growth rate is the only concern, LEDs at 720 Hz (1.4 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod stimulated plant growth the most. When energy consumption is the major concern, using LEDs at 180 Hz (5.5 ms) and 50% duty ratio with 16-h light/8-h dark photoperiod would not significantly sacrifice plant growth, especially when energy for heat removal is also taken into account.6. ConclusionsThe first sustained work with LEDs as a source of plant lighting occurred in the mid-1980s when a lighting system for plant growth was designed for space shuttles and space stations for it is realized that people cannot go to the Moon, Mars, or beyond without first mastering the art of indoor farming on Earth. As the performance of LED continues to improve, these lighting systems progress from red only LED arrays using the limited components available to high-density, multi-color LED chip-on-board technologies. Today, space age gardeners who have been testing high-efficiency light sources for future space colonists have identified energy efficient LEDs as the major light source not only to grow food but also to generate and purify oxygen and water—key sustainers of human life. The removal of carbon dioxide from a closed environment is another added benefit.LEDs are the first light source to provide the capability of true spectral composition control, allowing wavelengths to match to plant photoreceptors to optimize production as well as to influence plant morphology and composition. They are easily integrated into digital control systems, facilitating complex lighting programs like varying spectral composition over the course of a photoperiod or with plant development stage. LEDs do not contain mercury. They are safer to operate than current lamps since they do not have glass envelopes or high touch temperatures.While the process of photosynthesis does not require continuous light of full spectrum, LEDs can produce sufficient photon fluxes of specific wavelength on and off rapidly. Such mechanism of photosynthesis coupled with the solid state characteristics of LEDs constitute two ways of energy saving (cutting out unnecessary spectrum segment and turning off the light periodically) on top of the LEDs’ low power consumption. These are not easily achievable with other light sources.This paper provides a broad base review on LED applications in horticulture industry since 1990. These researches pave the way for the researches of similar types using different species and lead to comparable conclusion that LEDs are well qualified to replace its more energy demanding counterparts as controlled environment light source for agricultural research such as providing tissue culture lighting as well as supplemental and photoperiod lighting for greenhouses.With the energy it can save, LED’s becoming ec onomically feasible in large-scale indoor farming lighting applications is just around the corner.再生可持续能源评论高亮高效节能LED灯的来源及其在室内植物栽培中的潜力摘要自1980年中期以来，光电子技术的迅猛发展，显著调高了发光二极管（LED）的亮度和效率。
led节能灯的原理英文作文
led节能灯的原理英文作文The Principles of LED Energy-Efficient Lighting.In the ever-evolving landscape of lighting technology, the emergence of LED (Light-Emitting Diode) energy-efficient lighting has been a significant milestone. Not only have LED lights revolutionized the way we illuminate our surroundings, but they have also made significant strides in promoting sustainability and reducing environmental impact. Understanding the principles behind LED energy-efficient lighting is crucial to appreciating its impact and potential.At the heart of LED lighting lies the LED diode, a semiconductor device that emits light when electrical current flows through it. The fundamental components of an LED diode are a P-type semiconductor and an N-type semiconductor. The P-type semiconductor is doped with impurities that create "holes" or vacant positions in the crystal structure, while the N-type semiconductor is dopedwith impurities that add extra electrons.When a forward voltage is applied across the LED diode, electrons from the N-type semiconductor are attracted to the positively charged holes in the P-type semiconductor. This movement of electrons creates a current flow and, in the process, the electrons and holes recombine at the junction of the two semiconductors. This recombination releases energy in the form of photons, which are packets of light energy. The wavelength and color of the emitted light depend on the type of semiconductor material used in the LED.。
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- Close communication with customers with the great customer service
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to be... “always
there to illuminate your future”
Question ?
LED in our life
• LED lighting ---------------------------------------------------
• computer-----------------------------------
• TV----------------------
LED Market Continues to Grow
Global LED Market Forecast by segment($) 16000 14000 12000 10000 8000
6000 4000 2000 0 2007 2009 2012 2013
LED PRODUCT
- Technical knowledge - Current LED Market etc.
Place
Low-price products line:
Place
Luxury products line:
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1. Product design competition for students 2. Premium offer for students
Physical evidence
Physical evideቤተ መጻሕፍቲ ባይዱce: *Displaying LED lighting LED lighting packing etc Physical cues help customers evaluate LED lighting Before they buy it
Challenges of LED market
• LED production enterprises are facing a huge dilemma, an increased competition between the various enterprises
LED Product=Goods+Service
Main Marketing Strategies:
- Have two product lines
- Set the price & distribution channel accordingly.
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Conclusion
Main Marketing Strategies:
- Have two product lines
- Set the price & distribution channel accordingly.
- Let consumers experience Neo lamps with the best atmosphere in the stores
• • • • • • luminescence efficiency less power consumption long service life security reliability beneficial to the environment New stylist
New stylist
• traffic light----------------------------------
• Stage effects-------------------------------------------------
LED lighting owns following good values:
Customer
1, Customer service *Increasing technical stuff as customer support * Communicating with lighting retailers about LED lamp
2, Products service *Adapting LED lamp for the needs of clients *Processing quality LED lamp
+
Luxury Products line:Stylist design+excellent quality
Low price products line: target is general end users
LED processing Process
Customer
1, Customer service *Increasing technical stuff as customer support * Communicating with lighting retailers about LED lamp 2, Products service *Adapting LED lamp for the needs of clients *Processing quality LED lamp
Price
PH Products Neo (luxury line) Neo (low-price line)
$300
$250
$150
People
Retail store staffs. Not Neo staffs.
EDUCATE THEM.
People
Training for retail staffs:
LED Product=Goods+Service
+
Luxury Products line:Stylist design+excellent quality
Low price products line: target is general end users
LED processing Process
- Close communication with customers with the great customer service
- Intensive promotion to students
Physical evidence
Physical evidence: *Displaying LED lighting LED lighting packing etc Physical cues help customers evaluate LED lighting Before they buy it
MARKETING presentation
Jerry Ken Michael
What is LED?
• Light-emitting diode (LED) is a semiconductor light source. • Introduced as a practical electronic component in 1962.
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