Influence of different illuminations with xenon or microwave sulfur lamp on jointing and tillering of wheat

The emission of microwave sulfur lamp is mainly composed of visible light. The sulfur lamp, producing little infrared radiation, has high efficiency, long duration of illumination and less energy consumption. In order to probe the agricultural application of the lamp, experiments were carried out with wheat (cv. Yangmai 158) to emphatically study illuminating effects of xenon or sulfur lamp on tillering, jointing and net photosynthetic rate during tillering and jointing periods. Results indicated that there is almost no difference in net photosynthetic rate of wheat leaves growing under different lamps. Xenon lamp significantly advanced the time of jointing, decreased number of tillers, number of total leaves per plant and leaf size, as well as inhibited root growth. In contrast with xenon lamp, sulfur lamp evidently delays the time of heading and grain maturation, increased number of heads per plant, head length, total number of grains per plant, head weight and total grain weight per plant,

Analysis of the Energy and Environmental Sustainability of a Built Space System: The Case of Patte d’Oie University Campus in Ouagadougou

The aim of this study was to carry out a dynamic simulation of the energy and environmental performance of a built space system, with a view to assessing its energy and environmental class. The use of a simulation and modeling tool, supported by various methodological references, formed the basis of our approach. Adopting a systemic perspective, we described the structural and functional aspects of the systems making up built spaces, as well as the associated energy flows. Our approach was also based on a typology, taking into account typical days, structural and functional configurations at different scales and angles of observation. The analysis tool we developed in Java was applied to the built space system of the Patte d’Oie university campus in Ouagadougou. Annual electricity consumption was measured at 124387.34 kWh, closely aligned with the average annual electricity bill (125224.31 kWh), with a maximum relative deviation of 1%, followed by a carbon emission balance of 58337.66 kg eq CO2 per year. This validation confirmed the effectiveness of our tool. In addition, following the analysis of electricity consumption using our tool, the university campus was classified in energy class B and environmental class C. These results will be based on the emission factors of the energy mix of the West African Economic and Monetary Union (WAEMU) territory, with particular emphasis on Burkina Faso.

基于改进的YOLOV5算法对ADB汽车大灯的外界环境检测

针对远光灯交汇会影响汽车驾驶员的视觉注意力,导致汽车驾驶员夜间行驶安全难以得到保障的问题,研究基于机器视觉及深度学习的ADB汽车大灯的外界环境检测方法;通过机器视觉的CCD相机采集ADB汽车大灯外界环境图像数据,利用数据筛选方法剔除采集到的图像数据中干扰光源数据,依据路况特征差异,划定ADB汽车大灯外界环境检测目标区域后,通过深度学习算法检测外界环境目标车灯光源,结合扩展卡尔曼预测各目标车灯光源轨迹,当车辆前方有车灯光源经过时,ADB系统及时调整汽车远光灯对应区域灯珠亮度,减少在高速行驶时因远光灯交汇对汽车驾驶员的视觉影响,保障汽车安全行驶;实验结果表明,该方法可有效剔除各类干扰光源,准确检测目标车灯光源,且目标车灯光源轨迹预测结果与真实结果非常接近,可精准完成ADB汽车大灯的外界环境检测。

基于物联网技术的智能停车场系统设计

近些年来,停车场需求日益增大,许多国家致力于停车场管理系统的研究。但旧式的停车场管理方式需耗费大量人力、运转不科学并且大部分的停车场都不能及时查看车位信息。为解决这些问题,设计并实现了智能停车场系统。该系统的核心模块采用STM32,利用射频识别(RFID)模块实现停车场出入,采用重力系统监控停车位的实时使用情况,并通过蓝牙无线模块实现STM32与APP的通信。其中APP可以显示车位情况,通过出入2次刷卡的间隔计算停车时长与费用。经测试,发现该系统运行良好,能够为停车场的使用者提供更加便利的服务。

新能源汽车后雾灯散热器机械加工工艺设计

以某款新能源汽车中的后雾灯为机械加工研究对象,通过对后雾灯散热器零件的原材料、尺寸几何精度、表面质量和使用功能要求等进行逐一分析,牢牢抓住产品零件上76根散热小圆柱的成形作为设计的重点,经过多种可行加工方案的优化比较,选择了从冷挤压模具成形→冲裁模具冲压加工→数控铣削加工的主要加工工艺路径,并对实际生产过程中出现的质量缺陷进行分析并加以解决。实际生产证明,该后雾灯散热器的机械加工工艺设计合理可行,所生产的产品符合图纸技术要求,能够满足大批量生产的需求。

Functionally graded structure of a nitride-strengthened Mg_(2)Si-based hybrid composite

The ex-situ incorporation of the secondary SiC reinforcement,along with the in-situ incorporation of the tertiary and quaternary Mg_(3)N_(2) and Si_(3)N_(4) phases,in the primary matrix of Mg_(2)Si is employed in order to provide ultimate wear resistance based on the laser-irradiation-induced inclusion of N_(2) gas during laser powder bed fusion.This is substantialized based on both the thermal diffusion-and chemical reactionbased metallurgy of the Mg_(2)Si–SiC/nitride hybrid composite.This study also proposes a functional platform for systematically modulating a functionally graded structure and modeling build-direction-dependent architectonics during additive manufacturing.This strategy enables the development of a compositional gradient from the center to the edge of each melt pool of the Mg_(2)Si–SiC/nitride hybrid composite.Consequently,the coefficient of friction of the hybrid composite exhibits a 309.3%decrease to–1.67 compared to–0.54 for the conventional nonreinforced Mg_(2)Si structure,while the tensile strength exhibits a 171.3%increase to 831.5 MPa compared to 485.3 MPa for the conventional structure.This outstanding mechanical behavior is due to the(1)the complementary and synergistic reinforcement effects of the SiC and nitride compounds,each of which possesses an intrinsically high hardness,and(2)the strong adhesion of these compounds to the Mg_(2)Si matrix despite their small sizes and low concentrations.

基于人工智能的LED结温非接触式测量方法

根据LED芯片光谱的质心波长和半高全宽,构建了采用人工神经网络预测LED结温的方法。采用LED热阻结构分析系统测量不同衬底温度、不同电流下的结温,同时采用光谱仪测量相对光谱分布,选择GaN基芯片发出的蓝色光谱分布为研究对象,计算其质心波长和半高全宽,将质心波长、半高全宽和驱动电流作为输入参数,结温作为输出参数,构建人工神经网络。最后用该模型预测LED发光时的实际结温。研究表明,在采用大量数据学习后,本方法精度可以达到1.23℃,满足实际工程需求。此外,本方法不需要接触LED光源,准确性较高,具有明显的技术优势。

“双碳”目标背景下城市快速路照明设计理念研究——以南京城市三环为例

城市快速路是城市交通网络的重要组成部分,照明工程对于保障交通安全、居民生产生活需求具有重要作用。本文以南京城市快速路三环项目照明设计为例,结合“双碳”目标要求,系统阐释了照明设计理念及具体方案,重点介绍了一系列因地制宜的节能、安全措施,并对不同道路横断面进行了模拟测算,对城市照明工程设计实践具有一定参考意义。

LED城市道路照明灯具驱动电源维护方案探索

随着双碳政策的推行、绿色城市的发展,LED光源凭借其功耗低、光效高等优点在城市道路照明中广泛应用。本文主要介绍了LED城市道路照明灯具的应用情况以及维护中存在的问题,简述LED灯具驱动电源技术原理,推荐了LED灯具驱动电源统一的技术要求,探索出一种高效的LED驱动电源维护方案,为LED城市道路照明灯具维护标准化发展提供参考。

大功率LED车灯风冷散热系统性能优化研究

大功率LED车灯采用风扇进行强制对流散热,针对风扇周边空间尺寸影响车灯散热性能的问题,采用有限元仿真、均匀设计法及响应面分析相结合的研究方法进行优化研究。首先,利用有限元软件FloEFD研究了风扇护风罩与壁面的径向距离A、风扇入风口与壁面的距离B及风扇出风口与散热器的距离C三个设计参数对大功率LED车灯风冷散热系统散热性能的影响;然后,使用均匀设计法设计试验方案进行响应面分析并拟合出三个参数与LED焊点温度之间的回归模型,利用Pareto分析法确定三个参数对系统散热性能的影响大小;最后,利用Minitab软件的响应优化器,以LED结温最小化为目标,确认三个参数的最佳组合是A为8.4 mm、B为16.3 mm、C为4.3 mm。通过对最佳组合进行实验,表明此组合具有最优的散热性能,同时仿真和实验结果具有一致性,验证了仿真的可靠性。

Experimental Study and Modeling of a Convective Dryer for Fruits and Vegetables

The present work deals with the study of the thermal performances of a convective dryer for fruits and vegetables. This dryer, operating with energy generated from the combustion of biomass in a boiler connected to a water/air heat exchanger could be a solution to the problematic of energy related to drying. An experimental and theoretical study is carried out on the temperature profile inside the dryer. For this purpose, 10.3 kg of tomatoes were dried on the experimental setup. The operation lasted about 16 hours and reduced the moisture content from 93.8% to 12% in wet basis. The overall thermal efficiency of the convective dryer during the trial is 10.76%. For the theoretical study, the dryer components (boiler, water/air exchanger and drying chamber) are first modeled individually;the different sub-programs are then coupled to form the convective dryer program. The method of global heat balances combined with the one called “ε-NUT” is used. The set of equations is discretized using the implicit method of finite differences, then solved with the Gauss algorithm in Fortran 90. The theoretical results obtained are in good agreement with those measured.

光照条件对视觉心理的影响

光照条件参数包括持续时间、光照强度、色温等,这些条件的不同组合可在视觉心理层面对人类造成不同影响,并与心理疾病的发生或防治相关。光照时间的延长、昼夜节律的相位改变会增加双相情感障碍的发病风险;日间、夜间或全天光照强度的改变均会对心理产生影响,其中夜间暴露于光线增加抑郁症风险;另外,光的色温改变也会对警觉性、情绪等心理特征产生影响。本文就不同光照条件对视觉心理的影响进行综述。

关于智慧城市建设过程中智慧照明的思考

随着信息技术的不断发展,城市信息化应用水平不断提升,智慧城市建设也应运而生。在此进程中,作为城市公共服务基础之一,城市路灯有哪些可借鉴发展的经验,智慧照明应该怎样建设,怎样融入到智慧城市的建设进程中,这些问题需要不断地进行思考。

独立自由曲面LED汽车前雾灯的光学设计

为了使车辆驾驶员在雾、雪、雨或者尘埃等不同的恶劣气象条件下能够得到充分照明,且避免造成对方会车司机炫目,设计了具有明暗截止线的前雾灯系统。基于非成像光学理论,采用照度优化设计法,运用数值计算求解出自由曲面反射镜(FFR)各个点坐标的坐标值。合理划分基础面,并调整各子块的扩散角度,实现配光要求。通过蒙特卡洛模拟法进行追迹光线,测试结果表明:配光效果满足机动车前雾灯配光性能(GB4660-2016)对各测试点的照度要求,且明暗截止线清晰,体积小,边缘区域也有较高光能,光线利用率达到52.7%。

自然光照对眼部的影响（英文）

自然光照由连续光谱、不同能量的光组成,光的波长越短能量越大,故其中紫外线和蓝光具有更高能量。暴露在高强度光照下可能导致眼部组织细胞损伤,进而引起各种眼部结构的病理变化。我们回顾了近年来有关光照在角结膜、晶状体、前房结构、视网膜、视神经相关疾病中的作用的研究,综述了光照在眼部可能触发的信号通路和作用机制。眼组织过度暴露在光照下会导致DNA损伤增加、蛋白质的异常修饰和聚集,以及过度的氧化应激,从而导致眼部疾病的发生发展。因此,可根据所接触的光照特性与强度,以及需要保护的眼组织类型,针对性地单独或联合使用物理保护、局部和/或口服抗氧化剂和光照活化信号通路的小分子抑制剂,以防止和减少光照引起的眼部损害。

车灯面罩热板焊接温度场CAE模拟

针对塑件热板焊接中温度控制不精确影响焊接质量,且容易在塑料件上产生残余应力的情况,课题组对车灯面罩热板焊接的温度场进行了研究。基于ANSYS仿真平台对车灯面罩热板焊接进行温度场仿真分析,通过建立合理有效地温度场仿真模型得到了面罩热板焊接后的温度场分布,并通过实验验证了焊接过程中温度载荷、边界条件设置的合理性及仿真结果的正确性,最终得出车灯面罩热板焊接的仿真计算可行的结论。

模具修复锤击力信号的dbN小波阈值降噪方法

针对模具修复锤击力信号采集噪声干扰较大的问题,运用dbN(db为Daubechies的简写,N表示小波阶数)小波对锤击力信号进行小波分解低频系数信号重构。保留信号的低频系数,舍弃高频系数,重构后信噪比为10.077 8,均方根误差为0.663 3,初步实现了模具修复锤击力信号的降噪。在dbN小波分解的基础上进行阈值化处理,处理后的信噪比SNR明显提高,最大值为44.231 3 dB,均方根误差RMSE明显降低,最小值为0.012 5。实验结果表明两种方法都能实现对锤击力信号的噪声滤除,其中软阈值法还能较大程度的还原原始信号在突变点处的细节特征,避免了信号的失真,保证了模具修复锤击力信号后续计算准确性。

高能量高转换效率355 nm紫外激光器

为了得到一种三倍频效率高达60%的355 nm脉冲激光器,采用曲率半径分别为2 m的凹凸高斯镜和9 m的平凹全反镜组合作为谐振腔,加以电光调Q,得到1 064 nm高光束质量激光输出,再将其进行行波放大,获得重复频率10 Hz、脉宽7.3 ns、单脉冲能量1.01 J的1 064 nm基频光输出。利用Ⅰ类相位匹配LBO晶体进行二倍频、Ⅱ类相位匹配LBO晶体进行三倍频以得到波长为355 nm的紫外光输出。通过二倍频和三倍频输出特性和非线性晶体参数的分析和实验调试,最终获得了单脉冲能量为608 m J、脉宽为5.7 ns、线宽为2 nm的紫外激光输出。通过优化二倍频的转换效率,可使1 064 nm基频光到三倍频得到的355 nm紫外光的转换效率达60%。

车灯面罩板焊接应力场CAE模拟

车灯装配在进行热板焊接时,焊缝及其局部区域的材料在热载荷的作用下会产生一定的热应力,待车灯冷却后面罩内仍然有残余应力。基于ANSYS仿真平台对车灯面罩热板焊接进行应力场仿真分析,通过建立合理有效的温度场与应力场仿真模型,得到了面罩热板焊接后的应力,并采用载荷测量法搭建实验平台进行实验验证。结果表明,车灯面罩热板焊接的仿真计算可行。

基于ADB汽车前照灯的光学设计

为了避免由于远光灯使用不当而产生的一系列交通事故,且带给驾驶员更好的驾驶体验,设计了具有可以主动调整远光光束分布的自适应远光系统—ADB(adaptive driving beam)。基于非成像光学理论,采用照度优化设计法,通过计算来合理划分区域,控制相应LED的亮灭,以此达到不同远光光型的实现。通过蒙特卡洛模拟法追迹光线,测试结果表明:配光结果满足现行仅有的对自适应远光(ADB)配光规定,且当全部LED工作时,照度最大值为111 lx,模组光学系统效率为35.7%。