风冷溴化锂吸收式制冷机热力－传热耦合性能的研究

本文结合各设备的传热性能，通过计算机模拟，以无量纲量Ｆ／Ｆ为变量研究风冷溴化锂吸收式制冷机的热力－传热耦合性能，据此求得各设备换热面积的合理匹配值．计算结果表明，风冷溴化锂机各设备换热面积经合理匹配，可以显著减小风冷吸收器和冷凝器的换热面积，机组单位基管面积制冷量可因此提高４７％，而机组的性能系数ＣＯＰ值与水冷溴化锂机基本接近．     

SdIBM的非SU（3）解析内禀态

本文采用１／Ｎ展开技术，讨论了ＳｄＩＢＭ中由玻色子能量引起的ＳＵ（３）对称性玻缺，给出其１／Ｎ展开近似的内禀态解析表达式．     

用改进的MIPAES微量进样系统测定易挥发元素

对Hall的微量进样系统进行了改进,蒸发部分增加了一个套管,去溶部分加入了一定量浓硫酸。改进后的进样系统比较适用于MIPAES。在最佳实验条件下,对易挥发元素汞的检出限为0.002ng,精密度为3.6％(RSD),1000倍量的各种常见元素不干扰测定,记忆效应也不严重。对于相对难挥发元素铬和镍则效果较差,其检出限均为2ng。     

灰色离散系统的稳定性充分判据

本文利用一般离散系统的Lyapunov方程研究了灰色离散系统的稳定性问题,并给出了灰色离散系统的稳定性充分判据和应用实例。     

探讨利用3S技术对小区域生态环境变化的分析方法——以福州大学城周围环境为例

以福州大学城周边地区为例，探讨了利用“3S”技术对小区域生态环境变化进行综合分析的实用方法．利用从20世纪80年代至今的航空遥感（RS）数据，闽侯大学城周边区域乡界地图，植被覆盖的相关生态环境监测数据，基于全数字作业的遥感与地理信息系统（GIS）一体化技术提取研究区生态环境状况及其变化信息，综合运用“3S”技术，通过对遥感影像的分析，运用环境监测技术，进行大学城周边地区多年生态环境变化规律的研究．     

福建三明小湖赤枝栲群落组成结构及物种多样性分析

调查三明小湖赤枝栲自然保护区的 41个 10m× 10m样方 ,共 410 0m2 的群落面积 ,测定群落物种多样性特征 ,得到Margalef丰富度指数D1=14.5 6 14;Shannon Wiener多样性指数D2 =5 .4336 ;Simpson多样性指数D3 =0 .95 6 6 ;种间相遇几率PIE =0 .95 6 7;均匀度J =0 .7788.探讨乔木层、灌木层、及藤本的物种多样性特征值 ,其变化趋势与群落总多样性一致 .分析群落中 12个主要乔木种群的年龄结构 ,揭示群落乔木层主要建群种呈稳定型 ,表明该群落正处于相对稳定的群落演替阶段     

Ultrasonic flaw detection using EMD-based signal processing

The precise detection of flaw echoes buried in backscattefing noise caused by material microstructure is a problem of great importance in uhrasonic non-destructive testing （NDT）. In this work, empirical mode decomposition （EMD） is proposed to deal with ultrasonic signal. A time-frequency filtering method based on EMD is designed to suppress noise and enhance flaw signals. Simulated results are presented, showing that the proposed method has an excellent performance even for a very low signal-to-noise ratio （SNR）. The improvement in flaw detection was experimentally verified using stainless steel pipe sample with artificial flaws.     

Efficient analysis of dielectric radomes using multilevel fast multipole algorithm with CRWG basis

A full-wave analysis of the electromagnetic problem of a three-dimensional （3-D） antenna radiating through a 3-D dielectric radome is preserued. The problem is formulated using the Poggio-Miller-Chang-Harrington- Wu（PMCHW） approach for homogeneous dielectric objects and the electric field integral equation for conducting objects. The integral equations are discretized by the method of moment （MoM）, in which the conducting and dielectric surface/interfaces are represented by curvilinear triangular patches and the unknown equivalent electric and magnetic currents are expanded using curvilinear RWG basis functions. The resultant matrix equation is then solved by the multilevel fast multipole algorithm （MLFMA） and fast far-field approximation （FAFFA） is used to further accelerate the computation. The radiation patterns of dipole arrays in the presence of radomes are presented. The numerical results demonstrate the accuracy and versatility of this method.     

催化裂化柴油非加氢精制方法的研究进展

对催化裂化柴油非加氢精制改善其安定性的方法以及各种非加氢精制方法的原理、工艺的优缺点和技术经济分析方法等进行了综合论述。其中 ,酸碱精制、吸附精制、溶剂精制、加速老化、离子交换树脂精制等方法主要是把柴油中的不安定组分从柴油中分离出来 ,而加入稳定剂法是通过稳定剂来抑制不安定组分的反应 ,从而达到稳定柴油特别是催化裂化柴油的目的。提出了利用其中两种或几种非加氢精制方法对柴油进行精制的设想     

Effect of weld microstructure on brittle fracture initiation in the thermally-aged boiling water reactor pressure vessel head weld metal

Effects of the weld microstructure and inclusions on brittle fracture initiation are investigated in a thermally aged ferritic high-nickel weld of a reactor pressure vessel head from a decommissioned nuclear power plant.As-welded and reheated regions mainly consist of acicular and polygonal ferrite,respectively.Fractographic examination of Charpy V-notch impact toughness specimens reveals large inclusions(0.5-2.5μm)at the brittle fracture primary initiation sites.High impact energies were measured for the specimens in which brittle fracture was initiated from a small inclusion or an inclusion away from the V-notch.The density,geometry,and chemical composition of the primary initiation inclusions were investigated.A brittle fracture crack initiates as a microcrack either within the multiphase oxide inclusions or from the debonded interfaces between the uncracked inclusions and weld metal matrix.Primary fracture sites can be determined in all the specimens tested in the lower part of the transition curve at and below the 41-J reference impact toughness energy but not above the mentioned value because of the changes in the fracture mechanism and resulting changes in the fracture appearance.