Periodic thermal analysis and simple economics of collector and collector-reflector systems

This paper presents a simple transient thermal model for predicting the water temperature at any time during sunshine as well as off-sunshine hours using collector and collector-reflector systems. The transmittance-absorptance product used in theoretical calculation of the water temperature is taken as a function of solar altitude, solar azimuth angle, hour angle and tilt angle of collector and reflector. Fourier coefficients of the recorded data of solar intensity and ambient air temperature have been determined. Water temperature for the systems was determined at different water flow rates. The theoretical analysis is found to be in close agreement with experimental observations. From the theoretical and experimental recordings, it was found that water temperature in the range of 50–56.5°C can be had during sunshine hours using plane reflectors to collectors in a typical winter month. A simple economic analysis of the solar water heating systems has also been discussed. This can be used to calculate an optimum collector area.     

Relationship of marital status to incidence and prognosis of schizophrenia.

Schizophrenic patients were traced for 5.5 yr. following initial admission and were classified as Recovered (60 males, 52 females) if hospitalized for no longer than 6 mo. or Nonrecovered (23 males, 33 females) if hospitalized for at least 5 yr. In comparison with the Recovered group, patients in the Nonrecovered group were less likely to be married and showed inferior social and sexual adjustment prior to the illness. Combining the Recovered and Nonrecovered groups, the patients were less likely to be married than people of the same sex and age in the US population. Some variables (marriage, education, and work history) showed a differential relationship with incidence or prognosis of schizophrenia for the male and female patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

姿态角测试研究

研究飞行体姿态角测试技术,提出了一种姿态角测试方法,给出了可行的实现方案和实测曲线,用卡尔丹角结合测试曲线对被测体姿态进行了分析。通过实际测试,证明了该测试方法原理可行。     

地震波斜入射时水平层状场地的非线性地震反应

利用土层和半空间的精确动力刚度矩阵,可求解地震波斜入射,水平层状场地的动力响应,并可得到各土层的位移、应力及应变结果。结合等效线性化算法,可分析斜入射地震波(SH,SV,P)时场地的非线性地震反应。研究表明:入射角对地表的加速度峰值有重要影响,未必在波垂直入射时最大,可能有多个峰值;实际地震波入射角平均在60°左右,与斜入射SV波时峰值放大倍数最大值出现的角度基本一致,按垂直入射计算得到的结果可能不安全,表明了在场地非线性地震反应中研究斜入射的必要性。     

夏季日峰荷与有效温度的灰色建模及灵敏度分析

为了深入了解夏季日峰荷与气象因素之间的关系,定量掌握夏季气象因素对日峰荷的影响,作者首次提出用人体舒适度作为综合气象指标来反映夏季气象因素对日峰荷的影响.对2000年北京市夏季日峰荷与人体舒适度、日平均温度进行的灰色关联分析的结果表明:有效温度是对夏季日峰荷影响最大的关联变量.在此基础上建立了夏季日峰荷与有效温度的灰色GM(1,1)模型,并进行了单位有效温度的变化引起日峰荷增量变化的灵敏度分析,为电力部门在制定夏季运行方式或电力需求计划时,如何确定解释变量、定量地掌握夏季日峰荷随气象因素变化的规律提供了理论依据.     

Study of the interfaces in resistive switching NiO thin films deposited by both ALD and e-beam coupled with different electrodes (Si, Ni, Pt, W, TiN)

Thin NiO films, included in a metal/resistive oxide/metal (MRM) stack, are receiving great interest, as they exhibit resistive switching when subjected to an external applied field, and can thus be implemented in a resistive random access memory (ReRAM). The electrical switching characteristic is seen to depend on the NiO/metal coupling. Therefore a characterization of the interface between NiO and the electrode is vital to optimize and get insights on the switching phenomena. In this work we deposited NiO thin films by atomic layer deposition (ALD) at 300 °C and electron beam deposition (e-beam) at 40 °C on Si, Ni, Pt, W and TiN substrates and we characterized them with X-ray reflectivity (XRR), grazing incidence X-ray diffraction (GIXRD) and time of flight secondary ion mass spectrometry (ToF-SIMS). Depending on the growth process, we found an influence of the substrate on the NiO film roughness, which exhibits values in the 1.2-6.2 nm range. NiO electron density was 1.35-1.96 e⁻Å⁻³ spread around the nominal value of 1.83 e⁻ Å⁻³ for bulk cubic polycrystalline NiO. X-ray diffraction showed that NiO is polycrystalline in the cubic phase. ToF-SIMS profiles confirm NiO/Metal interface sharpness and the optimal uniformity of NiO layers. Intermixing phenomena are limited or absent and the presence of contaminants, such as C, F, and Cl is very low.     

法布里-珀罗型告警器激光入射角度的测量方法分析

分析了法布里-珀罗(Fabry-Perot,F-P)型激光告警器的工作原理,讨论了法布里-珀罗标准具摆动角、激光入射角度与折射角三者之间的关系,分析了计算来袭激光入射角度的方法。以波长为1.064μm的激光为例,针对3种不同的入射角,对透射光强随摆动角的变化情况进行了模拟计算。利用处理软件,对3种来袭激光入射角度进行了模拟测量,结果表明,能够较精确地测量出来袭激光的入射角度。     

插接管座超声波检测工艺的研究

插接管座焊缝的质量直接影响机组的安全运行,针对特定结构型式的插接管座,通过确定探头的入射角度和选择合适的晶片尺寸及探头频率,用超声波检测成功实现了插接管座角焊缝缺陷的定位。     

一类具有阶段结构和饱和发生率的生态流行病模型的稳定性

本文研究一类食饵具有阶段结构且捕食者染病的具有饱和发生率的捕食者-食饵模型的稳定性及其Hopf分支,讨论了由疾病的潜伏期引起的时滞对种群动力学性态的影响．通过分析特征方程,运用Hurwitz判定定理,讨论了该模型边界平衡点和正平衡点的局部稳定性,并得到了Hopf分支存在的充分条件;通过构造适当的Lyapunov泛函,运用LaSall不变集原理,讨论了该模型边界平衡点和正平衡点的全局稳定性,从而得到了疾病流行而最终形成地方病及消灭的充分条件．