职业技能鉴定质量分析初探

职业技能鉴定是推行职业资格证书制度的重要环节,鉴定的质量直接关系到职业资格证书的真实性、权威性。通过对试卷的有效性和可靠性的分析,以及对试题难度、区分度的分析,对职业技能鉴定质量的分析方法进行了探讨,阐述了质量分析在职业技能鉴定中的作用。     

试论融资租赁项下的进口贸易

阐述了当前跨国公司在合同中普遍采用的融资租赁的性质及融资租赁项下的进口贸易特点。     

The Synthesis of Sulfated Titanium Oxide Nanotubes

TiO₂ nanotubes can be prepared in gram quantities by treating anatase TiO₂ powder with concentrated NaOH solution. These TiO₂ nanotubes acquired strong acidity after being impregnated with sulfuric acid solution and calcined at 300 °C. The anatase TiO₂ powder used to prepare the nanotube did not catalyze the esterification between cyclohexanol and acetic acid, while sulfated TiO₂ nanotubes were very reactive toward the esterification reaction.     

Using motion from orthographic views to verify 3-D point matches

The specific problem addressed by the authors is how to detect the true match of a fourth point from among candidate matches in a situation in which three points have already been matched. The two sets of points to be matched are both subject to measurement errors. The depth error is more dominant than errors in the other two coordinates; however, the exact statistical distribution of the measurement errors is not known. The authors present a new method for solving the problem. The method is based on the technique of motion analysis using orthographic views. It discards the noisy z (depth) coordinates and uses only the x and y coordinates of the points to verify the match. The effect of depth errors on the motion estimate is completely prevented. Results show that this method is substantially more effective than previous methods that use all three coordinates     

钨合金废料的资源再生利用技术

钨是一种稀有金属，钨合金具有高的强度、硬度，较好的耐高温性、耐密性和良好的电性能。广泛应用于航空航天工业、兵器工业、核工业、信息产业、汽车工业和钢铁工业等行业。目前，钨资源短缺，钨合金价格高、用量大，因此各国都把废弃的钨合金作为宝贵的第二钨资源加以再生利用。本文综述了钨合金的再生利用现状，分别总结了硬质合金、高比重合金、钨铜合金和钨材的再生利用技术，并利用生态环境材料的观点。对每种再生利用技术作了简单的评价。     

基于DICOM标准全方向M型心动图的软件系统设计

本文介绍了基于DICOM标准全方向M型心动图软件系统的设计方案,详细分析了系统结构及各个模块功能.通过该系统可以直接准确地定量检测分析心脏各结构的舒、缩、形变过程及其数据,同时可以生成多个任意方向且互相同步的M型心动图.各个模块设计完全遵循DICOM标准,同时结合数据库管理,方便查询索引.该系统分析的影像数据可以来自PACS服务器,也可以来自本地系统,分析结果数据可以回传PACS服务器,也可以保存本地.该系统实现了国家发明专利"全方向M型心动图方法及其系统98 125713.5"系统数据和国际医学图像传递标准的接口.     

Influence of ethyl methacrylate content on the volume‐phase transition of temperature‐sensitive poly[(N‐isopropylacrylamide)‐co‐(ethyl methacrylate)] microgels

A novel series of temperature‐sensitive poly[(N‐isopropylacrylamide)‐co‐(ethyl methacrylate)] (p(NIPAM‐co‐EMA)) microgels was prepared by the surfactant‐free radical polymerization of N‐isopropylacrylamide (NIPAM) with ethyl methacrylate (EMA). The shape, size dispersity and volume‐phase transition behavior of the microgels were investigated by transmission electron microscopy (TEM), ultraviolet–visible (UV–Vis) spectroscopy, dynamic light scattering (DLS) and differential scanning calorimetry (DSC). The transmission electron micrographs and DLS results showed that microgels with narrow distributions were prepared. It was shown from UV–Vis, DLS and DSC measurements that the volume‐phase transition temperature (VPTT) of the p(NIPAM‐co‐EMA) microgels decreased with increasing incorporation of EMA, but the temperature‐sensitivity was impaired when more EMA was incorporated, causing the volume‐phase transition of the microgels to become more continuous. It is noteworthy that incorporation of moderate amounts of EMA could not only lower the VPTT but also enhance the temperature‐sensitivity of the microgels. The reason for this phenomenon could be attributed to changes in the complicated interactions between the various molecules. Copyright © 2004 Society of Chemical Industry     

Analysis of multiple FSS screens of unequal periodicity using an efficient cascading technique

In this paper, we present an efficient cascading procedure for analyzing frequency selective surface (FSS) systems consisting of multiple FSS screens of unequal periodicity embedded in multiple dielectric layers. In this procedure, we first find a global period for the FSS system by studying the composite in its entirety. Next, we compute the scattering matrix [S] of each of the FSS subsystems for the global Floquet harmonics by applying a relationship we establish that maps the [S] matrix of the subsystem for the individual Floquet harmonics to that for the global harmonics. This mapping-cum-filling process substantially reduces the effort needed to compute the [S] matrix of a subsystem. Finally, we compute the [S] of the entire system by applying a modified cascading formulation, in which one matrix inversion step is eliminated, resulting in a reduction in the total computing resource requirement as well as time. Two numerical examples are given to illustrate the efficiency and effectiveness of the technique.