Laminar natural convection in an inclined complicated cavity with spatially variable wall temperature

Natural convection in two-dimensional enclosure with three flat and one wavy walls is numerically investigated. One wall is having a sinusoidal temperature profile. Other three walls including the wavy wall are maintained at constant cold temperature. This problem is solved by SIMPLE algorithm with deferred QUICK scheme in curvilinear co-ordinates. The tests were carried out for different inclination angles, amplitudes and Rayleigh numbers while the Prandtl number was kept constant. The geometrical configurations considered were namely one, two and three undulations.The results obtained show that the angle of inclination affects the flow and heat transfer rate in the cavity. With increase in amplitude, the average Nusselt number on the wavy wall is appreciably high at low Rayleigh number. Increasing the number of undulations beyond two is not beneficial. The trend of local Nusselt number is wavy.     

超临界压力锅炉水冷壁倾斜并联内螺纹管内两相流不稳定性的试验研究

针对国产首台600 MW超临界机组在亚临界压力条件下的水动力特性,进行了倾斜并联内螺纹管内的汽液两相流不稳定性试验研究,观察到压力降型和密度波型两种类型的脉动。探讨了影响不稳定性的主要参数。并给出了发生不稳定性的阈值。试验表明:在超临界锅炉滑压运行设计参数条件下,水冷壁管内不会发生两相流不稳定性。图11表1参7     

在建筑中设置分布式供能系统站房的安全技术分析及对策

分析了原动机在民用建筑物内设置、运行可能产生的危险因素，根据这些危险因素分析阐述了机房设置的安全技术原则是预防为主，通过提供安全可靠的技术设备、多种检测手段及良好的通风环境，使发生事故的可能性降至最低。同时加强建筑物的安全措施做好准备，万一发生事故，能使事故产生的损失减小到最低限度。     

某流化床锅炉水冷壁爆管原因分析

对某流化床锅炉水冷壁在打水压上水过程中钢管泄漏破裂原因分析。     

14C labelling of lignins of normal and bm3 maizes for fermentation studies

[U-¹⁴C] phenylalanine (phe*) and [O¹⁴CH₃] sinapic acid (sin*) were infused into the cut ends of normal and bm3 maizes (anthesis stage) under or above the last node or at mid-internode, with or without the leaf, in light or in darkness. Radioactivity was measured in the organs, and in phenolic constituents of the cell wall and saponified residues of the bases and tops of the apical inter-node. In both maize genotype labelled under the node the radioactivity was distributed more evenly in the organs with sin* than with phe*. Infusion above the node and at mid-internode greatly increased radioactivity in the bases and tops, respectively. Removal of the leaf only slightly increased the radioactivity, mainly in the bases, and no clear-cut effect of darkness was observed. Phe* labelled the phenolic acids and the three lignin units, but the syringyl units of bm3 maize were only slightly labelled. Sin* specifically labelled the syringyl units, which represented the least condensed fraction of lignins. Both the native and labelled lignins were highly alkali soluble. There were differences in lignin biogenesis between the bases and tops, and between normal and bm3 maizes. The newly formed lignins were slightly different from the native lignins but had similar types of heterogeneity, with variations in the internode and between genotypes similar to those in native lignins. Provided due allowance is made for the distinguishing characteristics of newly formed lignins, the [¹⁴C-lignin] cell walls, which are strongly labelled on complementary structures, seem suitable model substrates for fermentation studies.     

建筑物对通信信号衰减的定量研究

建筑物墙体对信号的衰减对于通信信号在城市环境中的传播影响很大,透射信号的衰减是影响通信质量的重要方面。文中采用自由空间法建立测试系统,在300M～3GHz的频率范围之间对不同建筑物墙体进行信号穿过墙体透射衰减的实地测量,通过加权的算法得到建筑物的等效介电常数。同时,通过在固定频率下透射波和空旷地接受信号场强的比较计算得到透射系数,利用上述的固定频率下透射系数和等效介电常数结合菲涅尔公式反演其该频率下的等效电导率,得出建筑物墙体等障碍物在不同频率下的等效电导率。利用基于时域有限差分差分法的XFDTD软件进行仿真计算,结果验证仿真结果和实际测量结果比较吻合。     

负性液晶垂面排列（VA）盒中壁的研究

文章从理论上概述了外场作用下向列相液晶盒中出现的Bloch壁,使用负性液晶对两种垂面排列（VA）盒进行实验研究。两种液晶盒均使用垂面聚酰亚胺（PI）作为取向层,一种盒涂敷PI后使用了后工艺过程,另一种盒涂敷PI而没有后工艺过程。第一种VA盒在强场作用下出现壁,它事实上验证了涂敷PI后工艺过程的有效性。在外场作用下,第二种VA盒出现不同的不稳定现象。     

电视机安全检验中的抗电强度试验

简要介绍了抗电强度试验在电视机的安全检验中的实际作用介绍了判定电流、升压方式的选择。     

投影墙系统在电力调度系统中的应用

分析了在我国电网规模不断扩大,计算机及通信技术快速发展的形势下,电网调度中传统模拟屏的局限性,介绍了投影墙系统的优越性及北京供电局调度投影墙系统的结构和功能,为了弥补原产品功能的不足,作者在工作站上开发了一些软件功能模块,使投影墙系统与ＥＭＳ有机地结合起来,从而充分发挥投影墙系统的多用途功能,并允许多工作站多调度操作,这些模块还具有日志管理,操作权限管理,上墙内容限制,屏幕亮度控制和多机容错等多项     

南京商茂广场地下连续墙工程

地处繁华闹市区的深基坑工程的围护体系,对整个工程的成败尤为关键,围护墙和结构墙两墙合一,不仅作为基坑开挖期间挡设土止水的临时结构,也将作为今后地下室的永久性外墙使用,并与桩基共同承担建筑物上部荷载,是一种较好的既安全又经济的支护方法。