发动机冷起动测试系统设计与开发

通过对发动机冷起动参数同步测试的软件硬件开发,完成对发动机冷起动的电压、电流、发动机转速、进气温度、冷却液温度、机油温度等参数的同步测试,开发出发动机冷起动测试系统。     

小型创业企业生存分析

本文通过对小型创业企业相关数据的生存分析,使用生存表分析和半参数Cox模型,研究了小型创业企业的生存情况,通过数据分析,描绘了不同教育水平和性别的创业企业生存率表,通过对Cox模型预后因素的分析,建立了分层的Cox模型,模型表明教育水平对创业者的小企业创业生存影响显著。对模型的假设检验证明,文章建立的Cox模型是合理的。     

汽车坡道起步防溜系统设计

文章提出了一种汽车坡道起步防溜车系统设计,简洁扼要地阐述了具体的设计思路、方法。     

浅谈龙滩水力发电厂黑启动

介绍龙滩水力发电厂500k V系统全部失压,所有机组停机,厂用交流电源（包括外来电源）全部消失的情况下,利用柴油发电机电源恢复部分厂用电及按调度命令向系统恢复送电的处理过程。为国内电力行业提供黑启动交流和借鉴。     

模仿不应成为创新的起点

模仿不是创新,这已成定论。模仿对于创新的作用、模仿与创新的关系,已有过不少肯定的论述。许传宝先生的这篇文章,独辟视角,从模仿与创新的内涵出发,阐述了体育运动教学中动作模仿之于创新的负面作用。我们认为,此文的可看之处,不光在于其观点新颖,论述充分,对革新体育运动教学具有积极作用,更在于文章所蕴含的余味,在于它能给广大热衷于发明的广大读者提供有益的参考。     

Fresh start of Sino-German initiative on grassland investigation

The launch meeting for the second phase ofa Sino-Germany cooperative research project on the influence of rangeland management on matter fluxes in Inner Mongolia was held on 26 and 27 June at the CAS Grassland Ecosystem Research Station in Xilin Gol League in Inner Mongolia.     

CAS Institute of Information Engineering sees a good start

The Institute of Information Engineering (IIE), a new institute under CAS approved for establishment in 2011, has made a good start in its development in a recent year. By far, it has set up several state-level innovation platforms, including the State Key Laboratory of Information Security, the State Engineering Laboratory of Information Content Security Technology, the National     

人力资本与技术资本对我国海归创业意向影响

越来越多的海外留学人员选择回国发展。近6年回国发展的人数超过110万,是前30年回国人数的约3倍。海归创业将有利于推动我国经济发展。中国政府为鼓励海归回国创业,已经出台一些政策。哪些因素能够影响我国海归归国后的创业意向值得探讨。本文利用来自2011年底至2012年初由北京大学光华管理学院和中国与全球化中心联合进行的对海归人才的288份问卷调查,将海归回国后是否创业作为被解释变量,并从人力资本、技术资本和其他综合因素3个方面选取了10个解释变量对影响我国海归创业意向的因素进行了分析。分析表明,这3个方面均对海归归国后创业的概率均存在影响。在这3个方面中,影响较大的分别为学历、商业模式、第二产业,它们的边际作用分别为52.26%、30.93%、44.23%。本研究还存在一些不足,例如对描述海归心理特点和国内经营环境的变量尚未进行分析,有待进一步研究。     

1553B总线模块上电启动异常故障的分析与解决

机载计算机在系统上电时,1553B总线模块出现上电启动异常。从故障机理,时序逻辑和复位电路等方面分析,通过常温、高低温环境下的信号波形反复测试。分析定位为上电复位电路中的某电容导致上电复位信号爬升缓慢,产生抖动,引起1553B总线模块上电启动异常现象,对于此类现象采取有效措施,消除故障。     

Noise and oscillations in hot cathode arc

Gas discharges generate oscillations superimposed on random noise of several megacycles bandwidth.Positive ions oscillate in two distinct regions of the discharge, i.e., the plasma and the potential minimum at the cathode.The disturbances produced by the ion motions appear as voltage variations between the electrodes.Oscillations generated in the plasma are usually below 400 kc./sec., while “cathode” oscillations are about 700 kc./sec.As the discharge current is increased, the amplitude of the plasma oscillation increases while its frequency decreases. The random noise also depends on current, increasing rapidly as the Townsend discharge changes into an are. After arc conditions are fully established, the noise changes slightly with current. Probe studies show that the noise voltage between probe and cathode increases rapidly as space charge conditions change to permit acceleration of electrons to the probe. When the probe collects positive ions, the noise as viewed on an oscilloscope is coarse, i.e., lacking in high frequency components.An explanation of the noise generation may be found in the random fluctuations of space charge at the electrodes. Calculations based on this theory give voltage fluctuations of the observed order of magnitude.     

Microfluidic immunoassay for detection of serological antibodies: A potential tool for rapid evaluation of immunity against SARS-CoV-2

In December 2019, coronavirus disease 2019 became a pandemic affecting more than 200 countries and territories. Millions of lives are still affected because of mandatory quarantines, which hamstring economies and induce panic. Immunology plays a major role in the modern field of medicine, especially against virulent infectious diseases. In this field, neutralizing antibodies are heavily studied because they reflect the level of infection and individuals'' immune status, which are essential when considering resumption of work, flight travel, and border entry control. More importantly, it also allows evaluating the antiviral vaccine efficacy as vaccines are still known for being the ultimate intervention method to inhibit the rapid spread of virulent infectious diseases. In this Review, we first introduce the host immune response after the infection of SARS-CoV-2 and discuss the latest results using conventional immunoassays. Next, as an enabling platform for detection with sufficient sensitivity while saving analysis time and sample size, the progress of microfluidic-based immunoassays is discussed and compared based on surface modification, microfluidic kinetics, signal output, signal amplification, sample matrix, and the detection of anti-SARS-CoV-2 antibodies. Based on the overall comparison, this Review concludes by proposing the future integration of visual quantitative signals on microfluidic devices as a more suitable approach for general use and large-scale surveillance.     

Direct observation and manipulation of hot electrons at room temperature

In modern electronics and optoelectronics, hot electron behaviors are highly concerned, as they determine the performance limit of a device or system, like the associated thermal or power constraint of chips and the Shockley-Queisser limit for solar cell efficiency. To date, however, the manipulation of hot electrons has been mostly based on conceptual interpretations rather than a direct observation. The problem arises from a fundamental fact that energy-differential electrons are mixed up in real-space, making it hard to distinguish them from each other by standard measurements. Here we demonstrate a distinct approach to artificially (spatially) separate hot electrons from cold ones in semiconductor nanowire transistors, which thus offers a unique opportunity to observe and modulate electron occupied state, energy, mobility and even path. Such a process is accomplished through the scanning-photocurrent-microscopy measurements by activating the intervalley-scattering events and 1D charge-neutrality rule. Findings here may provide a new degree of freedom in manipulating non-equilibrium electrons for both electronic and optoelectronic applications.     

我国高校企业融入国际网络的思考

阐述了高校企业融入国际网络进行合作交流的必要性，分析高校企业自身发展状况和不同国际合作方式在合作过程中存在的障碍，对于高校企业理顺产权关系，增强国际合作意识，选择合适的合作形式，以及政府创造良好外部环境提出了建议。