Space Flight, Astronautics and Light Barrier

Amazing achievements and accomplishments of space science and technologies in the past half-century have profoundly affected all disciplines of natural science and engineering. By the end of 20(th) Century, man or man-made spacecrafts landed, or approached and surveyed all planets of solar system and their moons except Pluto. Biologists believe that life may emerge and evolve wherever liquid water exists. No liquid water is ever found yet on all planets and their moons in Solar System except for our Earth. Our mother planet turned out to be the only life-supporting oasis within 4 light years of the Milky Way. It is suggested in this article that time has come for science and engineering communities to study and prepare interstellar flight of manned or unmanned spacecrafts beyond Solar System. Four issues are to be addressed as prerequisite for such flight, namely, detailed survey of nearby space beyond Solar System, design of nuclear fusion rocket engine, long-sustainable on-board life-supporting system and breakthrough of the light barrier.

Protective and Regenerative Efficacy of a Plant Oil-Based Day and Night Cream: Investigated by a Novel Approach to Reveal the Impact of Blue Light Irradiation on Epidermal Barrier Integrity and Lipid Matrix

In recent years, the harmful effects of blue light (400 - 500 nm) as a component of visible light (400 - 700 nm) have increasingly gained attention of science, industry, and consumers. To date, only a few in vivo test methods for measuring the effects of blue light on the skin have been described. A direct measurement method that can detect the immediate effects of blue light on the epidermal permeability barrier (EPB) is still lacking. In this study, we present a new methodological approach that can be used to investigate both the protective and regenerative effects of cosmetic products on the EPB after blue light irradiation. In a study with 14 female volunteers, it was investigated whether the regular application of an O/W emulsion (day cream) can strengthen and protect the epidermal barrier against damaging blue light radiation of 60 J/cm2 (protective study design) and also whether a disruption of the epidermal barrier caused by blue light radiation is restored faster and better by the regular application of another O/W emulsion (night cream) than in product-untreated skin (regenerative study design). The two O/W emulsions are different in plant oil, active ingredient composition and texture. The seven-day treatment with the day cream initially led to a significant increase in the normalized lipid lamellae length in the intercellular space, whereas the irradiation with blue light after 24 hours led to a significant decrease in the lipid lamellae length in the untreated test area, but not in the area previously treated with the product. Regarding the regenerative study design, a two-day treatment with the night cream was able to restore a blue-light-induced decrease in lipid lamellae length in the intercellular space. In summary, with the study designs presented here, the protective and regenerative effect of two cosmetic products could be demonstrated for the first time on the integrity of the EPB after blue light irradiation and the data showed that the Lipbarvis® method is suitable for investigating the damaging effects of blue light on the EPB in vivo.

Formation and Gas Barrier Characteristics of Polysilazane-Derived Silica Coatings Formed by Excimer Light Irradiation on PET Films with Vacuum Evaporated Silica Coatings

The effects of excimer light irradiation on polysilazane coatings formed on PET films with vacuum-evaporated SiO2 coatings and the effects of these coatings on gas barrier characteristics have been investigated. The temperature during light irradiation has a large effect on the coating’s molecular structure and gas barrier characteristics. When irradiation was performed at 100℃, the polysilazane coating transformed into a silica coating, and a compact silica coating at a much lower temperature than with heat treatment alone was produced. Surface irregularities in the vapor-deposited silica coating were smoothed out by the formation of a polysilazane coating, which was transformed into a compact silica coating when irradiated with light, resulting in a significant improvement in the gas barrier characteristics. The water vapor permeability of the thin coating irradiated with excimer light at 100℃ showed only 0.04 g/m2•day (40℃, 90% RH). According to the results of investigation of temperature variation of water-vapor permeability, it is inferred that the developed film has an excellent gas barrier value, namely, 4.90 × 10–4 g/m2•day at 25℃. This gas barrier coated PET film is transparent and flexible, and can be used in the fabrication of flexible electronics. Also, the proposed fabrication method effectively provides a simple low-cost and low-temperature fabrication technique without the need for high vacuum facility.

Improvement of the carrier distribution with GaN/InGa N/AlGaN/InGaN/GaN composition-graded barrier for InGaN-based blue light-emitting diode

In Ga N light-emitting diodes（LEDs） with Ga N/In Ga N/Al Ga N/In Ga N/Ga N composition-graded barriers are proposed to replace the sixth and the middle five Ga N barriers under the condition of removing the electron blocking layer（EBL）and studied numerically in this paper. Simulation results show that the specially designed barrier in the sixth barrier is able to modulate the distributions of the holes and electrons in quantum well which is adjacent to the specially designed barrier. Concretely speaking, the new barrier could enhance both the electron and hole concentration remarkably in the previous well and reduce the hole concentration for the latter one to some extent along the growth direction. What is more,a phenomenon, i.e., a better carrier distribution in all the wells, just appears with the adoption of the new barriers in the middle five barriers, resulting in a much higher light output power and a lower efficiency droop than those in a conventional LED structure.

Improved carrier injection and confinement in InGaN light-emitting diodes containing GaN/AlGaN/GaN triangular barriers

In this study, an InGaN lighting-emitting diode （LED） containing GaN/A1GaN/GaN triangular barriers is proposed and investigated numerically. The simulation results of output performance, carrier concentration, and radiative recombination rate indicate that the proposed LED has a higher output power and an internal quantum efficiency, and a lower efficiency droop than the LED containing conventional GaN or A1GaN barriers. These improvements mainly arise from the modified energy bands, which is evidenced by analyzing the LED energy band diagram and electrostatic field near the active region. The modified energy bands effectively improve carrier injection and confinement, which significantly reduces electron leakage and increases the rate of radiative recombination in the quantum wells.

Efficiency enhancement of an InGaN light-emitting diode with a p-AlGaN/GaN superlattice last quantum barrier

In this study, the efficiency droop of an InGaN light-emitting diode （LED） is reduced slgnlncanUy oy using a p-AlGaN/GaN superlattice last quantum barrier. The reduction in efficiency droop is mainly caused by the decrease of electron current leakage and the increase of hole injection efficiency, which is revealed by investigating the light currents, internal quantum efficiencies, energy band diagrams, carrier concentrations, carrier current densities, and radiative recombination efficiencies of three LED structures with the advanced physical model of semiconductor device （APSYS）.

Droop improvement in blue InGaN light-emitting diodes with GaN/InGaN superlattice barriers

GaN/InGaN superlattice barriers are used in InGaN-based light-emitting diodes （LEDs）. The electrostatic field in the quantum wells, electron hole wavefunction overlap, carrier concentration, spontaneous emission spectrum, light-current performance curve, and internal quantum efficiency are numerically investigated using the APSYS simulation software. It is found that the structure with GaN/InGaN superlattice barriers shows improved light output power, and lower current leakage and efficiency droop. According to our numerical simulation and analysis, these improvements in the electrical and optical characteristics are mainly attributed to the alleviation of the electrostatic field in the active region.

Efficiency enhancement of InGaN based blue light emitting diodes with InGaN/GaN multilayer barriers

The advantages of InGaN based light-emitting diodes with InGaN/GaN multilayer barriers are studied. It is found that the structure with InGaN/GaN multilayer barriers shows improved light output power, lower current leakage, and less efficiency droop over its conventional InGaN/GaN counterparts. Based on the numerical simulation and analysis, these improvements on the electrical and the optical characteristics are mainly attributed to the alleviation of the electrostatic field in the quantum wells （QWs） when the InGaN/GaN multilayer barriers are used.

Improved efficiency droop characteristics in an InGaN/GaN light-emitting diode with a novel designed last barrier structure

In this study, the characteristics of nitride-based light-emitting diodes with different last barrier structures are analysed numerically. The energy band diagrams, electrostatic field near the last quantum barrier, carrier concentration in the quantum well, internal quantum efficiency, and light output power are systematically investigated. The simulation results show that the efficiency droop is markedly improved and the output power is greatly enhanced when the conventional GaN last barrier is replaced by an AlGaN barrier with Al composition graded linearly from 0 to 15% in the growth direction. These improvements are attributed to enhanced efficiencies of electron confinement and hole injection caused by the lower polarization effect at the last-barrier/electron blocking layer interface when the graded Al composition last barrier is used.

丹芪化瘀方含药血清对光损伤人视网膜色素上皮细胞保护机制研究

目的:探讨丹芪化瘀方含药血清对LED冷光源致人视网膜色素上皮细胞(ARPE-19)光损伤的防治作用及最佳药物剂量,探寻其可能存在的保护机制。方法:应用健康的SD大鼠制备丹芪化瘀方空白血清和含药血清,将0%(空白血清)及5%、10%、15%、20%含药血清作用于ARPE-19细胞,每组设6个复孔。各组加入相应的药物于细胞恒温培养箱中培养24 h后采用CCK-8检测细胞活力,筛选最佳含药血清浓度进行后续实验。实验设置对照组、空白血清组、低剂量、中剂量、高剂量含药血清组培养,采用实时荧光定量聚合酶链式反应(Real-time PCR)检测细胞中诱导型一氧化氮合酶(iNOS)、内皮型一氧化氮合酶(eNOS)、内皮素-1(ET-1)mRNA表达;酶联免疫吸附测定法(ELISA)检测一氧化氮合成酶(NOS)、一氧化氮(NO)、血管内皮生长因子(VEGF)含量;蛋白免疫印迹法(Western blot)检测对照组、空白血清组、高剂量组iNOS的蛋白表达水平。结果:筛选出16%丹芪化瘀方含药血清作为后续实验干预浓度。与对照组比较,空白血清组iNOS、ET-1 mRNA表达及NOS、NO、VEGF含量均升高(P<0.001),eNOS mRNA表达降低(P<0.001);随着含药血清浓度的增加细胞中iNOS、ET-1 mRNA表达及NOS、NO、VEGF含量逐渐降低,eNOS mRNA表达增加(P<0.001),与低、中剂量组相比,高剂量组的iNOS、ET-1 mRNA表达及NOS、NO、VEGF含量显著降低(P<0.001或P<0.01或P<0.05),eNOS mRNA显著升高(P<0.001或P<0.05);空白血清组iNOS蛋白水平明显高于对照组,而16%含药血清的iNOS蛋白水平明显低于空白血清组(P<0.001)。结论:丹芪化瘀方含药血清可能通过抑制iNOS/NO途径减轻细胞损伤,上调eNOS表达,下调ET-1、VEGF的表达,抑制脉络膜新生血管形成并改善血-视网膜屏障功能,从而发挥保护作用。

Dielectric Barrier Discharge Plasma-Induced Photocatalysis and Ozonation for the Treatment of Wastewater

The physicochemical processes of dielectric barrier discharge （DBD） such as insitu formation of chemically active species and emission of ultraviolet （UV）/visible light were utilized for the treatment of a simulated wastewater formed with Acid Red 4 as the model organic contaminant. The chemically active species （mostly ozone） produced in the DBD reactor were well distributed in the wastewater using a porous gas diffuser, thereby increasing the gas-liquid contact area. For the purpose of making the best use of the light emission, a titanium oxide-based photocatalyst was incorporated in the wastewater treating system. The experimental parameters chosen were the voltage applied to the DBD reactor, the initial pH of the wastewater, and the concentration of hydrogen peroxide added to the wastewater. The results have clearly shown that the present system capable of degrading organic contaminants in two ways （photocatalysis and ozonation） may be a promising wastewater treatment technology.

A GaN AlGaN InGaN last quantum barrier in an InGaN/GaN multiple-quantum-well blue LED

The advantages of a GaN-AlGaN-InGaN last quantum barrier （LQB） in an InGaN-based blue light-emitting diode are analyzed via numerical simulation. We found an improved light output power, lower current leakage, higher recombi- nation rate, and less efficiency droop compared with conventional GaN LQBs. These improvements in the electrical and optical characteristics are attributed mainly to the specially designed GaN-AlGaN-InGaN LQB, which enhances electron confinement and improves hole injection efficiency.

强脉冲光联合类人胶原蛋白敷料治疗面部色素沉着的疗效及相关测评指标变化评析

目的:探究强脉冲光联合类人胶原蛋白敷料治疗面部色素沉着的疗效以及对VISIA系统色素沉着评分和表皮油脂量、TEWL的影响。方法:选取从2021年1月-2022年6月在笔者医院收治的100例女性面部色素沉着患者,将所有患者按随机数字表法分配为对照组(n=50)、观察组(n=50),对照组使用强脉冲光治疗,观察组在对照组的基础上联合类人胶原蛋白敷料治疗;比较两组患者的疗效、VISIA系统色素沉着评分、皮肤屏障功能:包括表皮含水量、表皮油脂含量和经皮水分丢失量(TEWL)、SAS、DLQI评分的变化情况和不良反应的发生情况。结果:观察组患者治疗后总有效率(88.00%,44/50)高于对照组(P<0.05);与治疗前相比,治疗后观察组和对照组的VISIA系统色素沉着评分、TEWL、SAS、DLQI评分显著降低,表皮含水量、表皮油脂含量显著升高(P<0.05),治疗后与对照组相比,观察组的VISIA系统色素沉着评分、TEWL、SAS、DLQI评分显著降低,表皮含水量、表皮油脂含量显著升高(P<0.05);不良反应发生率,观察组和对照组比较,差异无统计学意义(P>0.05)。结论:强脉冲光联合类人胶原蛋白敷料治疗面部色素沉着的效果显著,可以促进色素沉着消退,改善皮肤屏障功能,改善患者生活质量和心理状态,且安全性较高。

DPL联合注射用透明质酸钠复合溶液在面部年轻化治疗中的应用

目的:探究精准脉冲光(Delicate pulse light,DPL)联合注射用透明质酸钠复合溶液改善面部年轻化的应用效果。方法:纳入2022年7月-2023年1月在北京积水潭医院皮肤科门诊就诊的女性就医者60例,随机分为对照组(予以DPL治疗,n=30)和观察组(予以DPL联合透明质酸钠复合溶液注射治疗,n=30)。连续治疗3个月,比较两组治疗前后面部肤质、皮肤屏障功能改善情况以及治疗中不良反应发生情况。结果:治疗后,两组就医者表面色素、红区、皱纹、毛孔、紫外线色斑、卟啉、棕色斑数据均下降,且观察组低于对照组(P<0.05)。治疗后,两组皮肤含水量、油脂含量均上升,且观察组高于对照组(P<0.05),两组表皮水分丢失量(Trans epidermal water loss,TEWL)均下降,且观察组低于对照组(P<0.05)。治疗后,观察组总有效率为100.00%,高于对照组的86.67%(P<0.05)。观察组不良反应总发生率为23.33%,高于对照组的13.33%,差异无统计学意义(P>0.05)。结论:DPL联合透明质酸钠复合溶液注射治疗用于面部年轻化治疗中可改善面部肤质情况,增强皮肤屏障功能,具有较高的疗效,且安全性较高。

照明行业碳足迹计算与碳标准发展现状

为打破国际“双碳”目标下的绿色贸易壁垒,完善国内碳排放的监管与认证体系,构建碳标准框架及系统梳理碳足迹计算方法成为一项迫切且必要的举措。本文首先阐述了“双碳”的背景,随后梳理了国际碳标准框架,并介绍了“双碳”数据库及软件。以灯具为例,概述了从原料、生产、组装、运输、使用、回收报废各过程的碳足迹计算存在的问题,旨在帮助读者迅速了解碳足迹计算过程和存在的挑战。同时,针对照明行业的碳标准制定提出了相关见解。

不同线宽电流阻挡层的GaN基LED芯片光电特性研究

发光二极管(LED)由于具有低功耗、小体积、宽光谱范围等优点,被广泛应用于可见光通信、光电医疗、快速无损检测等微系统领域。为了进一步提高LED的发光效率,在图形化蓝宝石衬底上制备了具有不同线宽电流阻挡层(CBL)的氮化镓(GaN)基LED,并研究其光电特性。结果表明,在120mA测试电流作用下,由于CBL的插入增大了有源层有效光发射区域的电流密度,减少了p电极(p-pad)下的寄生光吸收,LED芯片的辐射功率与光电转换效率随着CBL线宽的增加而单调增加,在CBL线宽设计为13μm时,辐射功率与光电转换效率达到最大;正向电压(VF)随着CBL线宽的增加略有增加,表明绝缘的CBL层增大串联电阻。本文为CBL线宽的选择提供了新思路,可有效提高LED的发光效率。

Al组分阶梯型渐变电子阻挡层深紫外LED性能研究

为减少电子泄漏改善发光性能,本文基于深紫外发光二极管(LED)提出了一种Al组分阶梯型渐变电子阻挡层(EBL)结构.通过数值研究,对比分析了不同EBL结构对深紫外LED发光性能的影响规律.结果表明,相较于传统EBL结构的深紫外LED(样品A),Al组分阶梯型渐变EBL结构的深紫外LED(样品B、样品C)最大内量子效率(IQE)分别提高了7.9%、14.2%,光输出功率(LOP)在200 mA下分别提升了73.3%、80.1%.这是因为Al组分阶梯型渐变EBL结构有效改善了EBL处极化效应引起的电场强度,进而减少了电子泄漏.

超晶格电子阻挡层周期数对AlGaN基深紫外发光二极管性能的影响

在AlGaN基深紫外发光二极管(DUV-LEDs)中设计了具有不同周期数的超晶格电子阻挡层(SL-EBL)结构,研究了SL-EBL周期数对DUV-LEDs发光效率、I-V特性、可靠性及有源区载流子复合机制的影响.研究结果表明,随着SL-EBL的周期数增加,DUV-LEDs的光输出功率(LOP)、外量子效率(EQE)和电光转换效率(WPE)均呈先上升后下降的趋势,同时泄漏电流减小,可靠性提升.当周期数为7时(厚度为28 nm),DUV-LEDs裸芯的EQE和WPE均达到最大值,在7.5 mA注入电流下分别为3.5%和3.2%.能带模拟结果证明了增加SL-EBL周期数可以有效提升电子势垒高度,而几乎不改变空穴势垒高度.然而,当SL-EBL超过一定厚度时,抑制了空穴向有源区的注入,导致EQE和WPE随SL-EBL周期数变化出现拐点.研究了SL-EBL周期数对DUV-LEDs载流子复合机制的影响,发现增加SL-EBL周期数可以有效地降低有源区内载流子非辐射复合.

背界面纳米光子结构提高透明导电氧化物基超薄Cu(In, Ga)Se_(2)太阳能电池电学性能的理论探究

透明导电氧化物(TCO)基超薄Cu(In, Ga)Se_(2)(CIGSe)太阳能电池具有建筑光伏一体化的潜力,然而由于背肖特基结的存在,其增大背复合速率S_b在提高空穴传输的同时也增加了光生电子背复合,从而抑制了其性能的提高。本文使用1D-SCAPS软件对背界面纳米光子结构(NPs)如何提高电池的性能进行理论探究,结果表明,背界面NPs的引入产生了复杂的电学效应。一方面,NPs本身不吸收光能,从而降低了背界面附近的有效光吸收体积,导致背界面光生载流子浓度降低,光生电子的背复合显著降低;另一方面,NPs的引入增加了吸收层厚度,导致空间电荷区(SCR)远离背界面,降低了其对光生电子的收集效率,增加了背复合。在高背复合速率(S_(b)=1.0×10^(7)cm·s^(-1))下,光生载流子浓度降低产生的背复合降低大于SCR移动产生的背复合增加,因此总体的背复合降低。与此同时,背复合的降低还缓解了高S_b时的光生电子损耗,从而解除了随S_b增大而增加的背复合对电池性能的抑制。这些发现为设计和优化TCO基超薄CIGSe太阳能电池提供了参考。

通过诱导载流子的V坑传输提升GaN基绿光LED的空穴注入效率

为了提升GaN基多量子阱LED的空穴注入效率,设计了具有不同最后势垒层结构的GaN基多量子阱外延结构,并将其制备为绿光mini-LED发光芯片,利用低温电致发光光谱、电流电压特性测试对其载流子传输机制进行了研究。结果表明,在采用AlGaN或GaN/AlN最后势垒层的样品中,有更多载流子可以传输到深层量子阱,空穴注入效率获得提升。本文对这一现象中的载流子运输机制以及V坑缺陷在其中所起的作用进行了研究,发现这种提升主要来自空穴V坑注入比例的增大。实验还发现,过大的V坑注入比例也会造成非辐射复合率上升,从而抑制了AlGaN最后势垒层样品的电光转换效率。