GC–MS characterization of oligomers in polyadipates used as plasticizers for PVC in food contact

Fourteen commercial polyadipates and a polysebacate were analysed for their components of a molecular mass below 1000 Da, primarily with the aim of generating the background data for measuring the migration of this type of polymeric additives from plasticized PVC (e.g. cling films and gaskets of lids) into foods or food simulants. Since the composition of the material <1000 Da varies between the polyadipates, the main components must be identified to enable a correct quantification. Polyadipates differ in the diol used as linker, their termination (acid or alcohol) and in the end‐capping (free alcohols, acetylation, acylation with fatty acids, esterification with octanol/decanol). Gas chromatography (GC) provides good separation, but the material remaining in the column up to high temperatures decomposes and forms a hump in the rear part of the chromatogram. Examples of mass spectra are shown, the most indicative fragments pointed out and spectra of 159 components listed. The polyadipates and the sebacate are characterized by their structure, the main components <1000 Da and the fraction of material <1000 Da. Copyright © 2006 John Wiley & Sons, Ltd.     

An efficient method for developing requirement specifications for plant control software using a component-based software prototype

This paper proposes an efficient method to develop requirement specifications for Plant Control Software (PCSW) using software-component-based prototypes. Prior to this proposal, domain analyses were conducted on existing PCSWs, and their functions were classified into “similar functions” and “individual functions”. Then PCSW Software Components (PSC: PCSW Software Component, PSCs: PCSW Software Components) were developed to correspond to these functions. PSCs as parameter-style components were developed in order to satisfy the clients’ (we define clients as owners, managers and operators of plants) requirements. A support environment for developing requirement specifications was developed. The environment consists of the Prototype Development Tool (PDT), the Behavior Check Simulator (BCS) and the Requirement Specification Development Tool (RSDT). The method consists of four steps. In the first step, PDT is used to define the parameters to customize PSCs and to compose a PCSW prototype by setting these parameters to PSCs. In the second step, BCS is used to execute the composed PCSW prototype and check its behavior and relevancy against the clients’ expectations. In the third step, steps 1 and 2 are repeated until the behavior of the PCSW prototype satisfies the clients’ requirements. Finally, a requirement specification is developed from the PCSW prototype which fully reflects the clients’ requirements. In order to evaluate the proposed method, it has been applied in five development cases. A Requirement Coverage of 91%, a Requirement Revision Rate of 6%, a PSC Reuse Rate of 92% and a LOC Reuse Rate of 83% have been achieved. In addition, a reduction of 55% in the amount of time required to develop requirement specifications has been achieved. These results indicate that the proposed method has sufficient capability to develop an exhaustive and an adequate PCSW requirement specification. And the developed PSCs have sufficient functions and capability to compose PCSW prototypes, and the support environment is capable of shortening the time taken to develop requirement specifications.     

卷边槽钢压杆考虑板组约束作用的屈曲系数

卷边槽钢压杆的局部屈曲具有相关性。《冷弯薄壁型钢结构技术规范》(GB50018-2002)提出适用于各种不同截面的板组约束系数的统一计算公式来考虑这种相关性。但由于板组组成的多样性,其是否合理,有待于进一步研究。借助ANSYS有限元分析软件,对卷边槽钢压杆局部屈曲进行分析,得到考虑板组约束作用的屈曲系数,并和国内外规范进行比较。结果表明,计算结果和英国规范吻合较好,我国规范偏于安全较多。借鉴英国规范的形式,给出考虑板组约束作用的屈曲系数的计算公式,这些公式可供进一步修订规范时参考。     

Air entrainment in fresh concrete with PFA

The results of a study into the influence of PFA on air entrainment in fresh concrete are discussed It is shown that the required dosage of AEA to produce an air content of 5.5 ± 0.5% in a PFA modified concrete mix is two-six times that required in the corresponding neat OPC concrete mix. The dosage of a vinsol based air entraining agent (AEA) required appears to be directly related to the PFA content of the mix. Similar direct relationships were obtained with a range of different PFAs. The dosage of an AEA based on the salt of a fatty acid appears to be sensitive to both PFA and OPC contents. For the type of PFA used, the variability of measured air content or the amount of air retained after continued agitation both indicated that vinsol based AEAs show the highest variability whilst fatty acid based AEAs show low variability. The between batch variability of air content was significantly improved by the addition of PFA regardless of the AEA used.     

福禄宫“蝼蜂窠”制作技术初探

福禄宫位于湖南长沙市城西区,始建于清代光绪年间。解放后,福禄宫因未及时修理维护,朽损情况严重,1983年底被拆毁。通过对残留木制装修构件拼凑,推算出该建筑的蝼蜂窠部分测绘图。福禄宫蝼蜂窠类似于北方斗栱中的平身科,是一种装饰性构件。福禄宫的昂嘴采用翼龙飞凤交错排列的形式,部分昂嘴端部另加雕饰花板。蝼蜂窠采用层层叠置出踩的形式,其表面只施以桐油或光油等透明涂料,未施其它色漆及彩绘。     

巨磁电阻材料的研究与应用

介绍了一种新型的磁性功能材料－巨磁电阻材料，综述了其研究进展情况。并就它在巨磁电阻传感器、高密度磁记录读出磁头、巨磁电阻随机存储器以及自旋晶体管等磁电子元器件上的进行了论述。     

提高杂质泵过流部件品质的工艺技术

从杂质泵过流部件的需求现状和失效分析、材质和化学成分选用时的量化指数 ,介绍了护套、后护板、前护板 ,叶轮等铸造工艺 ,热处理工艺要点 ,提出了提高杂质泵过流部件品质的闭环系统。     

Tasting green leaf volatiles by larvae and adults of Colorado potato beetle,Leptinotarsa decemlineata

Larvae and adults of the Colorado potato beetle,Leptinotarsa decemlineata (Say), are shown to have galeal gustatory cells that are highly sensitive to distillate of potato leaf extracts, (E)-2-hexen-1-ol, (E)-2-hexenal, and other saturated and unsaturated six-carbon alcohols. In larvae and adults, the sensory response patterns elicited by leaf homogenate, leaf distillate and a mixture of these two extracts differ in subtle ways. Beetle larvae feed most readily on Millipore disks treated with leaf homogenate and the mixture, but they did not feed on disks treated with leaf distillate. The differences in behavioral response and sensory input are used to derive a potential gustatory code that may stimulate different levels of feeding. This code may be disrupted by compounds present in nonhost leaves, thus leading to reduced feeding. Possible interactions of sapid leaf volatiles, amino acids, sugars, and potentially deterrent plant compounds are discussed.     

Visualising a knowledge mapping of information systems investment evaluation

Information systems (IS) facilitate organisations to increase responsiveness and reduce the costs of their supply chain. This paper seeks to make a contribution through exploring and visualising knowledge mapping from the perspective of IS investment evaluation. The evaluation of IS is regarded as a challenging and complex process, which becomes even more difficult with the increased complexity of IS. The intricacy of IS evaluation, however, is due to numerous interrelated factors (e.g. costs, benefits and risks) that have human or organisational dimensions. With this in mind, there appears to be an increasing need to assess investment decision-making processes, to better understand the often far-reaching implications associated with technology adoption and interrelated knowledge components (KC). Through the identification and extrapolation of key learning issues from the literature and empirical findings, organisations can better improve their business processes and thereby their effectiveness and efficiency, while preventing others from making costly oversights that may not necessarily be only financial. In seeking to enlighten the often obscure evaluation of IS investments, this paper attempts to inductively emphasise the dissemination of knowledge and learning through the application of a fuzzy Expert System (ES) based knowledge mapping technique (i.e. Fuzzy Cognitive Map [FCM]). The rationale for exploring knowledge and IS investment evaluation is that a knowledge map will materialise for others to exploit during their specific technology evaluation. This is realised through conceptualising the explicit and tacit investment drivers. Among the several findings drawn from this research, the key resulting knowledge mapping through FCM demonstrated the complex, multifaceted and emergent behaviour of causal relationships within the knowledge area. The principal relationships and knowledge within IS investment evaluation are illustrated as being determined by a blend of managerial and user perspectives.     

锌系工件的静电粉末涂装和工艺管理

讨论了锌系工件喷涂的相关工艺、现场管理、技术参数、质量检验和环境要求等。