利用谱线宽度测人发中的微量元素

通过实验证明了可以利用谱线宽度做永久工作曲线用于光谱定量分析。给出了用于测量人发中微量元素Ｃｕ，Ｚｎ，Ｆｅ和Ｃａ的永久工作曲线，利用这些工作曲线对实际样品进行了测定，所得结果与用ＩＣＰ－ＡＥＳ测得的结果相吻合。     

单重工作休假M/M/c排队驱动的流体模型分析

该文在M/M/c排队驱动系统中加入工作休假策略,研究了单重工作休假多服务台排队驱动的流体模型.利用拟生灭过程和矩阵几何解法得到驱动系统稳态队长分布.构建净输入率结构,导出流体模型的稳态联合分布函数满足的的矩阵微分方程组,进而利用Laplace-Stieltjes变换(LST)方法得到稳态下缓冲器库存量的空库概率及均值表达式.最后,给出模型在多信道无线Mesh网下的应用,通过数值例子展示参数变化对系统性能指标的影响.     

工质对微通道沸腾液膜瞬态变化的影响

本文采用去离子水和无水乙醇两种工质,利用微通道流动沸腾同步测量实验系统,研究了液膜厚度的瞬态变化规律,实验发现流动沸腾形成的初始液膜厚度在毛细数Ca很宽的范围内都遵循Taylor流动原理;液膜形成后,在蒸发和蒸汽流动携带的耦合作用下,厚度迅速减薄直至蒸干;由于水的汽液黏度比小,速度梯度小,剪切作用带来的液膜厚度减少量小,且水的汽化潜热大,吸收相同热量时蒸发量小,导致水的液膜厚度变化斜率较小,通过理论分析提出了沸腾液膜厚度变化的计算模型,计算结果与实验结果的误差小于20%。     

Study on Planar Whispering Gallery Dielectric Resonators. I. General Properties

Several basic properties of homogeneous planar Whispering Gallery dielectric resonators are investigated through a general approach. In particular the values for the minimum and maximum allowed radius, defined by irradiation and dielectric losses, respectively, are obtained in terms of the complex dielectric constant of the involved media. The same approach is employed in the analysis of the limit allowed frequencies of a fixed family of mode, leading to the definition of the ideal frequency band. The role of the transverse mode is then discussed, and the effective frequency band is introduced and determined both in simple disc and circular ring resonators. The extension of the effective band is limited at least by a factor 3, in terms of decades, in comparison to the extension of the ideal one; this limitation, due to the presence of transverse modes, can be overcome using suitable designed nonhomogeneous resonators, as discussed in a following companion paper.     

用于白天自适应光学的波前探测方法分析

提出了两种视场偏移哈特曼波前传感器，用于探测白天条件下强背景中目标信号的波前信息.给出了哈特曼波前传感器子孔径中焦面上天光背景非均匀性分布特征的实验结果，详细分析了基于分光棱镜的双焦面视场偏移哈特曼波前传感器的探测误差，并通过基于倾斜镜的单焦面视场偏移哈特曼波前传感器实验给出了波前测量的结果，证明视场偏移哈特曼波前传感器能够精确、稳定的测量白天条件下目标信号的畸变波前信息，同时给出了其在白天条件下探测能力的估算结果及其受限因素，估算结果表明云南天文台的自适应光学系统在10 W/m²·sr天光背景条件下应用视场偏移哈特曼波前传感器能对5等星(可视星等值)目标进行准确的波前探测. 关键词： 自适应光学 波前传感器 白天工作 误差分析     

Application of Complexity Theory to an Information Processing Model in Science Education

The current work examines the role of working-memory capacity in problem solving in science education. It treats an information-processing model with tools of complexity theory. Nonlinear methods are used to correlate the subjects' achievement scores with working-memory capacity. Data have been taken from the achievement scores in simple organic-synthesis chemical problems. The subjects (N = 319) were in grade twelve (age 17–18). Problems of various Z-demands (that is the number of steps needed to solve the problem) from two to eight were used. Rank-order sequences of the subjects, according to their scores, were generated, and each score was then replaced by the value of subject's working memory capacity measured by the digit backward span test. Then the sequences were mapped onto a one-dimensional random walk model and when treated as dynamic flows were found to possess fractal geometry with characteristics depending on the Z-demand of the problem. The findings were interpreted using concepts from complexity theory, such as correlation exponents, fractal dimensions and entropy. The null hypothesis was tested with surrogate data.     

新型平板热管换热器热回收效率特性实验研究

本文针对普通住宅房间设计了一台新型平板式热管换热器,该换热器结构紧凑、体积小巧。为研究该换热器的使用条件,本文开展了不同工质(R113、R141b以及这两种工质的混合物)对该热管换热器换热效率影响的实验研究。整个实验在夏季工况下进行,热管真空度为1×10~(-3)Pa,充液量(灌入热管换热器内的工质体积与热管换热器体积之比)为1/3。实验结果表明:该热管换热器热回收效率较高。在整个风量范围内,R141b作为工质的热管换热器换热效果最好,最高效率达到了58.2%。     

带止步与中途退出策略的M~x/M/1/N单重工作休假排队系统

研究了带有止步和中途退出的M~x/M/1/N单重工作休假排队系统.顾客成批到达,到达后每批中的顾客,或者以概率b决定进入队列等待服务,或者以概率1-b止步(不进入系统).顾客进入系统后可能因为等待的不耐烦而在没有接受服务的情况下离开系统(中途退出).系统中一旦没有顾客,服务员立即进入单重工作休假.首先,利用马尔科夫过程理论建立了系统稳态概率满足的方程组.其次利用矩阵解法求出了稳态概率的矩阵解并得到了系统的平均队长、平均等待队长以及顾客的平均消失概率等性能指标.最后通过数值例子分析了工作休假时的低服务率η和休假率θ这两个参数对系统平均队长的影响.     

修理工单重定期休假可修系统更换模型研究

针对修理工带有单重休假的单部件可修系统,提出了一种新的维修更换模型.假定系统是可修的,逐次故障后的维修时间构成随机递增的几何过程,系统工作时间构成随机递增的几何过程,在修理工休假时间为定长的情况下,分别选取系统的总工作时间T和故障维修次数N为更换策略,以长期运行单位时间内的期望效益为目标函数,通过更新过程和几何过程理论建立数学模型,导出了目标函数的解析表达式,通过最大化目标函数来获取系统最优的更换策略T*和N*.并在一定条件下给出了策略N比策略T优的充分条件.最后,通过数值例子验证了方法的有效性.     

电热炮原理性实验研究

本文介绍了电热炮的基本原理、实验装置结构、等离子体发生器和发射实验结果。实验结果表明,电热炮原理实验的装置是成功的,已将19.3g复合弹丸加速到1.85km/s,穿透30mm厚的钢板。