Optimal analysis of a space solar dynamic power system

The major purpose of the present study is the theoretical modeling, numerical simulation and optimal analysis of a space solar dynamic power system. Using the method of system analysis, a mathematical and physical model is developed to describe the process of energy transfer and conversion in a space solar dynamic power system. As a new assessing criterion for total launch mass, it is proposed to combine the system mass and aerodynamic drag area into a unified criterion. The effects of the configurations and operating parameters on the system performance are analyzed and the optimal scheme of a space solar dynamic power system is obtained by numerical simulation.     

Effects of temperature steps on human skin physiology and thermal sensation response

Air-conditioning is frequently used as a means of adjusting indoor thermal environment in hot-and-humid areas. However, when entering an air-conditioned building from outdoors people may experience thermal discomfort and risk health consequence if the instantaneous change of air temperature exceeds the thermoregulatory capacity. A study was conducted to investigate the alteration in thermal perception and in thermoregulation that simultaneously occurred in response to temperature step in a thermal transient. In this study, two temperature down-steps from 32/28 to 24 °C and an up-step from 20 to 24 °C were created in a climatic chamber consisting of two microclimate-controlled rooms, and subjects were evaluated for change in thermal sensation as well as in skin physiological properties, including skin capillary blood flow (SCBF), skin moisture, transepidermal water loss (TEWL), and skin temperature over the course of acclimation. As the results show, a cold sensation overshot occurred in thermal sensation vote (TSV), skin temperature, and SCBF in 1 min after the temperature dropped from 32 to 24 °C. TSV correlated the best with skin temperature (r = 0.60) and moderately with skin moisture and TEWL (r = 0.42–0.54) when the temperature down-step reached 8 °C. TEWL acclimated in a two-stage pattern, demonstrating a difference between the sensational change and thermoregulation. The gender-specific influence occurred in thermoregulation but not in subjective sensation. The findings of the study suggest that thermoregulatory burden might be adequately controlled when the temperature step in thermal transition zone is limited to 4 °C or lower.     

汽轮发电机组实时能损监测及分析系统

根据火电厂实际经济运行和生产管理的需要,设计了实时能损监测及分析系统。实践表明,该系统不仅可在线监测火电机组热力系统的实际运行状态,而且能根据各项能损偏差,诊断运行经济性优劣,指导运行人员的操作,其实时性克服了传统分析方法严重滞后的缺点,对提高电厂运行的经济性和安全性起到了重要作用,具有很好的推广价值。     

Enhanced Hole Mobility and Reliability of Panel Epi-Like Silicon Transistors Using Backside Green Laser Activation

The hole mobility and reliability of green continuous-wave laser-crystallized epi-like Si transistors on glass panel substrates were enhanced by source/drain activation by backside green laser irradiation. Green laser energy was scanned uniformly across junctions since the gate structures included no interference, in an attempt to conduct super visible-laser lateral activation. The enhancement was thus explained by the formation of continuous improved epi-like Si microstructures with reduced grain defects and with a barely increased number of interface defects over the entire channel/junction. The hole mobility in such laser-activated devices was as high as 403 cm² /V^.s, which doubles that of thermally activated devices.     

高效液相色谱-串联质谱法测定大米中高氯酸盐含量

目的建立高效液相色谱-串联质谱法测定大米中高氯酸盐的含量。方法样品提取液经过固相萃取柱快速净化处理后去除基质干扰物,采用Thermo Acclaim TRINITY P1色谱柱分离,以乙腈-20 mmol/L甲酸铵为流动相进行梯度洗脱,流速为0.3mL/min,柱温30℃,外标法定量检测。结果在高氯酸盐浓度为1.0～100.0 ng/mL的范围内的线性相关系数较好(r=0.999),检出限为4.0μg/kg,定量限为10.0μg/kg,高、中、低3个浓度水平的加标回收率在82.3%～93.2%之间,测定值的相对标准偏差小于5%(n=6)。结论该方法简便快捷、灵敏可靠,适用于大米中高氯酸盐的快速检测。     

仿生叶脉分形微结构表面的平板热管传热性能研究

基于植物叶片的蒸腾作用,以叶脉结构作为蓝本,设计了分形角度为50°、60°、70°、80°、90°的仿叶脉槽道结构,并将其应用于平板热管冷凝端。其中上一级槽道与下一级槽道的长度比、宽度比均为0.7,第一级槽道长度为16.0 mm、宽度为2.0 mm、深度为0.3 mm,并且设置一组未经表面处理的平板热管作为对照。实验结果表明:分形角为80°时性能最优,其冷凝热阻最小可达39.420℃/kW,相比未经表面处理平板热管的热阻降低了40.29%;相对于传统的直槽道结构,置于冷凝端的仿叶脉槽道结构能极大地降低工质流阻,有利于工质回流。     

High-Throughput Screening for Phase-Change Memory Materials

Phase change memory (PCM) is an emerging non-volatile data storage technology concerned by the semiconductor industry. To improve the performances, previous efforts have mainly focused on partially replacing or doping elements in the flagship Ge-Sb-Te (GST) alloy based on experimental “trial-and-error” methods. Here, the current largest scale PCM materials searching is reported, starting with 124 515 candidate materials, using a rational high-throughput screening strategy consisting of criteria related to PCM characteristics. In the results, there are 158 candidates screened for PCM materials, of which ≈68% are not employed. By further analyses, including cohesive energy, bond angle analyses, and Born effective charge, there are 52 materials with properties similar to the GST system, including Ge₂Bi₂Te₅, GeAs₄Te₇, GeAs₂Te₄, so on and other candidates that have not been reported, such as TlBiTe₂, TlSbTe₂, CdPb₃Se₄, etc. Compared with GST, materials with close cohesive energy include AgBiTe₂, TlSbTe₂, As₂Te₃, TlBiTe₂, etc., indicating possible low power consumption. Through further melt-quenching molecular dynamic calculation and structural/electronic analyses, Ge₂Bi₂Te₅, CdPb₃Se₄, MnBi₂Te₄, and TlBiTe₂ are found suitable for optical/electrical PCM applications, which further verifies the effectiveness of this strategy. The present study will accelerate the exploration and development of advanced PCM materials for current and future big-data applications.     

Learning to Caricature via Semantic Shape Transform

International Journal of Computer Vision - Caricature is an artistic drawing created to abstract or exaggerate facial features of a person. Rendering visually pleasing caricatures is a difficult...