三维圆弧型井眼轨道设计模型的拟解析解

为了研究三维圆弧型井眼轨道设计方程组是否存在解析解以及如何有效求解，使用消去法从多元非线性方程组中推导出其中的某个未知数满足一个特征多项式方程，并且证明了该方程组的拟解析解可以由特征多项式方程的实数根和已知设计参数构成的解析公式计算得到；如果极点多项式非恒等于0，则当特征多项式次数不超过5时，如果有解则为解析解，否则为数值解。通过使用C++类实现多项式加减法、乘法的计算方法，提出了多项式实数根的分隔算法、并用二分法快速求解出多项式全部实数根的计算方案。该方法在数学上经严格推导，计算方案简洁、稳健，在三维井眼轨道设计、智能钻井定向控制中具有应用价值。     

Evaluation of a large dish‐type concentrator solar lighting system for underground car park

To utilize solar energy more efficiently and reduce lighting power consumption in underground public spaces such as car park, a large dish‐type concentrator solar lighting system is put forward along with its evaluation, which is a unique design to apply a laminated layer of beam split thin‐film coating and thin‐film solar cells onto the dish reflector. The collected sunlight is split into 2 parts, one being reflected into a fiber optical bundle and transmitted for daylighting, while the rest being absorbed by solar cells for electricity generation as the other way to replenish daylighting. A set of 4 solar lighting systems using 3.28‐m diameter dish are designed to meet the lighting requirement in a 1771‐m² underground car park. A mathematical model is adopted to calculate the output power and conversion efficiency of solar cells distributed on the parabolic dish surface. The indoor illuminance distribution is given by lighting simulation. The results indicate that the average daylight illuminance in the car park can vary between 62.7 and 284 lx on February 25, 2016 and between 62.7 and 353 lx on August 17, 2016 for 2 chosen days, respectively. For the presented design, the electricity produced by solar cells is just enough to power light‐emitting diodes for lighting meeting a criterion at night. Considering about 19% conversion efficiency of solar cells and the efficacy of 129.5 lm/W of light‐emitting diodes, the hybrid solar lighting system can have about 40% utilization ratio of solar energy, so it can be concluded that a sufficient lighting provision can be provided by the proposed large dish‐type concentrator solar lighting system for applications in underground car park.     

叶酸片联合阿托伐他汀治疗对H型高血压患者同型半胱氨酸及颈动脉粥样硬化的影响

目的:分析H型高血压患者应用叶酸片与阿托伐他汀联合治疗对血浆同型半胱氨酸及颈动脉粥样硬化的影响。方法:选取我院2016年1月至2018年10月收治的140例H型高血压患者为研究对象，按随机数字表法分为观察组（70例）和对照组（70例），对照组给予常规降压+阿托伐他汀钙片治疗，观察组给予常规降压+阿托伐他汀钙片+叶酸片治疗，疗程均为10周。比较2组治疗前后同型半胱氨酸（homocysteine，Hcy）、低密度脂蛋白（low-density lipoprotein，LDL）、肱踝脉搏波传导速度（brachial-ankle pulse wave velocity，BaPWV）、颈动脉内膜-中膜厚度（carotid intima-media thickness，IMT）、血压及心率水平变化，并观察不良反应发生情况。结果:观察组治疗后血浆Hcy及LDL水平明显低于对照组（P<0.05）；两组治疗后BaPWV和IMT比较差异均有统计学意义（P<0.05）；治疗后，两组患者的收缩压和舒张压较治疗前均明显降低（P<0.05），且观察组治疗后的收缩压和舒张压明显低于对照组（P<0.05），但两组治疗后心率比较差异无统计学意义（P>0.05）；两组不良反应发生率比较无统计学差异（P>0.05）。 结论:对于H型高血压应用阿托伐他汀联合叶酸片治疗可有效减轻患者颈动脉粥样硬化程度，降低Hcy及LDL水平，且临床较为安全。     

印刷电路板缺陷检测的实际应用

电路板在我们的日常生活中非常常见,这就使得印刷电路板的缺陷检测显得尤为重要。AOI作为新兴的检测PCB板缺陷的系统,在生产实际中正在被大家熟知并且应用。相较于传统的检测方式,AOI系统比较灵活,无论是在检测时间还是系统运算上,或者是对相关技术人员的要求相较于传统方式都比较有优势,本文就AOI系统在实际中的应用展开讨论,分析并且介绍了在实际应用中的具体细则。     

Scientists as political experts: Atomic scientists and their claims for expertise on international relations, 1945–1947

This paper explores the construction of scientists' expertise on international affairs through a study of the rhetoric of U.S. atomic scientists during public and policy‐making debates on the international control of atomic energy between 1945 and 1947. It explores the claims scientists made about the nature of their expertise on issues of diplomacy and international relations and how their expertise was produced and reproduced. The paper shows that scientists were able to successfully project themselves, in the public domain, as experts on political and diplomatic matters related to the atomic. In calling for the international control of atomic energy, scientists constructed their expert knowledge in contrast to, as they portrayed it, the failed expertise of diplomats and political thinkers. In boundary work through their speeches, articles, and government testimonies, scientists drew a line between the political and the scientific, but argued that, as scientist‐citizens, they were able to take their rational thinking from one realm into the other.     

Availability growth models and verification of power equipment

The general availability growth models for large scale complicated repairable system such as electric generating units, power station auxiliaries, and transmission and distribution installations are presented. The calculation formulas for the maintenance coefficient, mathematical expressions for general availability growth models, ways for estimating, and fitting on checking the parameters of the model are introduced. Availability growth models for electric generating units, power station auxiliaries, and transmission and distribution installations are given together with verification examples for availability growth models of 320–1000 MW nuclear power units and 1000 MW thermal power units, 200–1000 MW power station auxiliaries, and 220–500 kV transmission and distribution installations. The verification results for operation availability data show that the maintenance coefficients for electric generating units, power station auxiliaries, transmission and distribution installations conform to the power function, and general availability growth models conform to rules of availability growth tendency of power equipment.