日本食品安全标准体系及其监管体制初探

日本已经建立了一套比较完善的食品安全标准体系和管理体制,其食品安全标准体系以颁布食品法律、法规为主,辅之以技术标准的制定,其管理体制是通过食品安全委员会对农林水产省和厚生安全省的食品安全管理工作进行协调。日本通过法律法规的修订、安全标准的修补、管理体制的改革,夯实了其食品安全管理的法律基础,优化了其食品安全标准框架,完善了其食品安全标准体系细则,理顺了其食品安全监管的行政体制,强化了其对食品安全的管理。     

大型发电机励磁装置防静电生产工艺研究

大型发电机励磁装置的工作效能是极为重要的,因此需要减少静电,保障其正常工作。本文对于其进行研究,通过对其研究现状与工作原理分析,对其元件贮存、元件领用、电路板焊接和生产装配过程进行了探讨,为其进一步发展打下坚实的基础。     

基于ANSYS的隔膜泵十字头的强度分析

隔膜泵属于新一代往复泵,是所在工艺系统的心脏设备,对其运行可靠性有很高要求,对其传动端的零件强度也有很高的要求.其传动端的零件十字头的有限元分析文献很少,本文通过阐述其工作原理,对其受力情况进行分析,用限元分析软件ANSYS对十字头进行强度计算,对设计生产提供指导意义.     

事业单位人力资源管理存在的问题及对策

事业单位是指国家以社会公益为目的的,由国家机关举办或者其他组织利用国有资产举办的,从事教育、科技、文化、卫生等活动的社会服务组织,其公益性决定了其在社会发展中不可替代的地位和角色,其公益服务质量不仅代表着其单位效能,更代表着党和国家的形象。其人力资源管理制度的优劣直接决定着其服务质量,现阶段,事业单位在人力资源管理上取得了一些成就,但也必须看到存在着不少的问题,笔者通过剖析其问题,找到对策,希冀为人力资源管理提供一些新的思路和方法。     

大飞机的性能测量以及数据处理方法研究

大飞机在设计过程中,需要通过一定的飞行试验对其其性能参数进行测量,以便于其在实际应用中,具有较好的应用性能,在其性能测量过程中,涉及到大量的数据处理工作,在相关数据的处理过程中,应用高效的数据处理方法,保证其具有良好性能是非常必要的,本文就主要对其巡航、爬升、下降、着陆等过程中的性能测量及数据处理方式进行简单分析,有利于其应用性能的提升。     

菲利浦·斯塔克的创作特点

菲利浦·斯塔克是简约主义的代表人物,其设计理念亲民与环保,希望生活在工业化大生产时代的人们能够用较少的钱买到较好的商品;其具有跨界设计的思维,这不但使其设计作品小到简单的生活用品,大到建筑、室内设计、家具等,几乎涵盖了现代人们生活的方方面面,而且使其设计具有较强的创新性;其设计风格诙谐幽默,因而其作品能给生活在充满竞争与压力时代的人们带来会心一笑。     

60MN叠加式力标准装置机架结构设计及优化

文章首先针对力标准装置钢架结构主要结构型式及其优缺点进行分析,然后提出了60MN叠加式力标准装置机架结构的设计方案,并利用有限元软件ANSYS对60MN叠加式力标准装置的机架在最大载荷的工况下进行了有限元分析,对其进行强度分析,检查其受力情况,评估其安全性,发现其强度不足后对其结构进行改进,改进后进一步对其进行有限元分析,经过优化设计后,机架结构强度满足要求。     

煤沥青的改性及其机理研究进展

煤沥青具有资源丰富、价格低廉等优点,但其残炭率低,可以通过改性来提高其残炭率。简要介绍了改性煤沥青的制备方法及近几年来国内外改性煤沥青的发展状况,并探讨了其机理。由于煤沥青组成复杂,并不能知道其确切的反应机理,只能根据测试结果提出其可能的改性机理。     

交联聚乙烯海底电缆绝缘层热老化寿命及理化性质分析

交联聚乙烯(XLPE)海底电缆绝缘层在热老化过程中使用寿命会受到影响,其微观理化性质也会产生变化。通过对未运行的海底XLPE电缆绝缘层进行模拟加速热老化试验,测定其断裂伸长率保留率,结合Arrhenius公式推导出其老化寿命。并利用傅里叶变换红外光谱分析其羰基指数、差示扫描量热法分析其结晶度,探究其老化的理化性质。研究表明,其热老化寿命能达到80年,并且羰基指数随着热老化时间的延长而增大,结晶度随热老化时间延长先增大后急剧减小;随着XLPE结晶度的升高,羰基指数增加,其断裂伸长率保留率减少。     

移动通信基站遭受雷击时的空间电磁分布及影响

城市建筑物上的移动通信基站,仅做好其自身的雷击防护措施是不够的,还应当考虑其遭受雷击时给周边环境带来的影响。从移动通信基站遭受雷击时,其周边空间的电磁场分布和感应电动势入手,用数据来说明移动通信基站的存在,是怎样给其所处及周边建筑物内的电气、电子设备带来危害的。因此,针对城市建筑物上的移动通信基站,在对其防雷设施进行完善的同时,也应对其给周边环境带来的雷电影响进行评估,考虑到其给周边的电气、电子设备带来的间接影响。     

Effect of electrostatic charge of particles on hydrodynamics of gas-solid fluidized beds

The aim of this work was to investigate effect of electrostatic charge of particles on the fluidization hydrodynamics. Behavior of bubbles in beds of polyethylene particles was studied through analysis of pressure fluctuations in the frequency domain. Fluidized beds of uncharged, pre-charged and bed-charged particles were used in the experiments. Results revealed that in the bed of pre-charged particles, compared to uncharged experiments, particle-particle repulsive force increases the bed voidage and reduces equilibrium bubble size while the transition velocity to turbulent fluidization is decreased. In the case of bed-charged particles, at low gas velocities bubble fraction is greater compare to the other cases due to faster bubble coalescence in the presence of particle-wall attractive electrostatic force. Electrostatic charge of bulk increases by increasing the gas velocity. At high gas velocities, the repulsion force between highly charged particles overcomes the particle-wall effect on bubble formation and reduces the bubble size to less than in uncharged experiments. Accumulation of particles near the wall in the bed od bed-charged particles affects the hydrodynamics in two ways: first it accelerates bubble growth via bubble coalescence at low gas velocities, second it limits the bubble growth and reduces the transition velocity to turbulent regime to a value less than for pre-charged particles.     

Comparison of the fatigue behaviour of two different forms of PMMA

This study investigates the fatigue behaviour of two forms of polymethylmethacrylate (PMMA): pure PMMA in the form of acrylic glass and PMMA-based bone cement. Acrylic glass demonstrated superior fatigue strength compared to hand-mixed porous bone cement but was significantly weaker than pore-free bone cement. The greater fatigue strength of bone cement in comparison to acrylic glass was attributed to its composite-like microstructure, containing pre-polymerized beads which are absent in the amorphous structure of acrylic glass. In tests conducted on notched specimens, the porous bone cement demonstrated superior fatigue strength to acrylic glass. The results could be predicted using the theory of critical distances, with errors no larger than 14%. This approach allowed us to show that, although porosity had a negative influence on the fatigue strength of the plain specimens in comparison to acrylic glass, the presence of porosity had no effect when the samples contained a notch or a hole. This finding is interesting when considering the effort put into removing porosity from bone cement during surgical operations, where it is used in situations where there are sharp stress concentrations in the form of protruding bone and the design features of artificial implants.     

Assessment of the cause of cracking of hydraulic hose clamps

The aim of this study was to determine the cause of failure of the shells of hydraulic hose crimped fittings. For the purpose of examination the damaged crimped shells, undamaged crimped shells and shells prior to crimping were used. Fractographic and metallographic analysis, including chemical microanalysis of inclusions, were performed to determine the cause of failure. For this investigation, optical and scanning electron microscopes and hardness measurement were used. Damaged crimped shells contained higher amount of inclusions compared to undamaged crimped shells and substantially differed in microstructure and hardness. Furthermore, different geometry of the cross section at outer edge containing more effective stress concentrators was observed on failed crimped shells. Based on microstructural observation in cross section, hardness measurements and analysis of inclusions, the conclusion is that cracking of the shells occurred mainly due to deviations in the manufacturing process, combined with lower quality of shell material. Modifications to the technology were suggested to prevent this kind of failure.     

Graphitization of inner surface of copper beam duct of KEKB positron ring

In order to evaluate the best technique to reduce electron cloud instability, we measured the electron cloud density in copper ducts coated with titanium nitride and non-evaporable getter used in the KEK B-factory (KEKB) positron ring. In this study, we developed a new system for the graphitization of copper beam ducts. The graphitization of a copper surface by intense electron bombardment resulted in the reduction in the secondary electron yield (SEY) to 1.0 in a laboratory experiment and to 1.1 in a real beam duct. The electron cloud density in the graphitized duct is 30% lower than that in an uncoated copper duct. Thus, it has been confirmed that the graphitization of a beam duct leads to a reduction in the electron cloud density in the duct.     

深度法在Fe基合金耐熔锌腐蚀试验中的应用

熔融的液锌对Fe基合金有很强的腐蚀作用,判断Fe基合金的耐熔锌腐蚀性能对选择Fe基合金材料有重要的作用.近年来普遍采用深度法来测量Fe基合金在熔锌中的腐蚀速率.深度法具有方法简单、测量准确、腐蚀界面能够反映腐蚀过程以及多次测试的优点,已越来越被广泛地应用在Fe基合金耐锌蚀测试中.     

Evaluation of solid dispersions of Clofazimine

Clofazimine (CLF) was formulated with polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) as a solid solid dispersion (SSD) to increase the aqueous solubility and dissolution rate of the drug. Different molecular weights of PEG (1500, 4000, 6000, and 9000 Da) and PVP (14,000 and 44,000 Da) were used in different drug:carrier weight ratios (1:1, 1:5, and 1:9) and their effect on the dissolution performance of the drug was evaluated in USP Type 2 apparatus using 0.1 N HCl medium. The dissolution rate was compared with corresponding physical mixtures, a currently marketed soft gelatin capsule product, and free CLF. The effect of different methods of preparation (solvent/melt) on the dissolution rate of CLF was evaluated for PEG solid dispersions. Saturation solubility and phase solubility studies were carried out to indicate drug:carrier interactions in liquid state. Infrared (IR) spectroscopy and X-ray diffraction (XRD) were used to indicate drug:carrier interactions in solid state. Improvement in the drug dissolution rate was observed in solid dispersion formulations as compared to the physical mixtures. The dissolution rate improved with the decreasing weight fraction of the drug in the formulation. Polyvinyl pyrrolidone solid dispersion systems gave a better drug release profile as compared to the corresponding PEG solid dispersions. The effect of molecular weight of the PEG polymers did not follow a definite trend, while PVP 14,000 gave a better dissolution profile as compared to PVP 44,000. Improvement in saturation solubility of the drug in the solid dispersion systems was noted in all cases. Further, IR spectroscopy indicated drug:carrier interactions in solid state in one case and XRD indicated reduction in the crystallinity of CLF in another. It was concluded that solid-dispersion formulations of Clofazimine can be used to design a solid dosage form of the drug, which would have significant advantages over the currently marketed soft gelatin capsule dosage form.     

Prevention of browning of the peel of pears by polyethylene film packaging

Polyethylene film packaging was investigated as to its use in preventing the browning of the peel of the pear variety 'Le Lectier' during distribution. The fruits were individually packaged in polyethylene bags, and were found to be superior to the usual paper-packaged fruit or unpackaged fruit in that browning of the peel was reduced considerably, while the loss in weight or wilting also was reduced and the preservation of external freshness was excellent. However, the use of a perforated polyethylene bag was essential in order to prevent the browning of the flesh or core that occurred with unperforated polyethylene bags. This browning was considered to be a physiological disorder resulting from carbon dioxide, judging from the composition of the head-space gas in the bag. The oxidative enzyme activity of the fruit was measured and an electron-microscopic observation of the epidermis was carried out. As a result, it was clear that enzymatic activity increased markedly following ripening of the fruit and a structural defect was observed in the cuticular layer of the epidermis.     

SiCp/Al复合材料焊接综述

为实现SiCp/Al复合材料的高质量可靠焊接,推广SiCp/Al复合材料在各领域的应用,调研了国内外SiCp/Al复合材料不同焊接方法的研究现状。在熔化焊方面,国内外学者通过调整工艺参数、在焊缝中加入Ti元素发生诱发反应等方法,抑制了焊缝中Al4C3针状脆性相的形成,从而提高了焊接接头的力学性能。在搅拌摩擦焊方面,国内外学者针对不同材料设计了专用的焊接搅拌头,以保证它们具备高耐磨性与足够的冲击韧性,在焊接过程中不出现破损情况;关注了焊接过程中焊接头转速、焊接速度、轴向力与热输入等因素,以获得力学性能优秀、晶粒细小均匀的焊接接头。在扩散焊方面,国内外学者探究了中间夹层对焊缝界面间原子相互扩散的促进作用;采取不同工艺参数,以外加超声或电子束表面加热等方式促进了原子间的相互扩散,以获得力学性能优异的焊接接头,提高焊接效率。在钎焊方面,国内外学者通过探究钎料与SiCp/Al复合材料之间的润湿性来组合钎料与钎剂,通过化学腐蚀处理表面暴露颗粒增强相、在复合材料表面电镀金属等方法来增大钎料与增强相的润湿性、解决钎料铺展受阻的问题,以进一步提高钎焊焊接接头质量。     

中国传统工艺振兴语境下的工匠精神

目的针对目前国家大力保护非物质文化遗产、倡导传统工艺振兴的语境下,如何传承和发扬好工匠精神,以促进当前我国非遗的保护和传统手工艺的传承与发展。方法以文献考据的方式,详细论述我国历史上不同时期关于工匠和工匠精神的解读,从古代"工"或"匠"到现代"大师"的演变,以及数千年来我国工艺文化传统所凝结成的大匠气度和大师境界,即将技艺臻于极致,将作品琢至完美的"工于技艺,匠心独运"的当代工匠精神。结论传承和发扬工匠精神须从政府加强指导、社会全力推崇、艺人珍视声誉等几方面形成合力,从而推动我国传统工艺行业的健康发展。