解读新国标GB／T10004-2001

一．引言 新的国家标准GB／T10004-2008《包装用塑料复合膜、袋干法复合、挤出复合》自今年8月1日开始实施，由于我本人也是该标准的起草人之一，最近几个月中，有很多制造蒸煮袋企业的老朋友，都来电咨询相关内容。其中最集中的问题有三个：第一个是这个新国标为什么不适用于含铝箔的三层（PET／AL／CPP或OPA／AL／CPP）、四层（PET／AL／OPA／CPP或OPA／AL／PET／CPP）以及三层塑料结构（PET／OPA／CPP、     

注射成形高分子混料可制成A级表面

聚碳酸酯混料，如拜耳材料公司出产的PC／PET或PC／PBT非常适用于汽车零件制造。例如，由矿物强化的PC／PET或PC/PBT混料以及由玻璃纤维强化的PC／ABS混料可用于制造汽车后背阻流板或天线盖。例如，用于大众汽车的Golf GTI、Polo GTI等的后阻流板。制成的零件，表面光洁达到A级，无需预处理即可直接喷漆。由于这种材料重量轻，制成的零件均比SMC制成的轻。[第一段]     

中国生物分解塑料产业现状

牛物分解塑料是指在自然界如土壤和／或沙土等条件下，和／或特定条件如堆肥化条件下或厌氧消化条件下或水性培养液中，由自然界存在的微生物作用引起降解，并最终完全降解变成二：氧化碳（CO2）或／和甲烷（CH4）、水（H2O）及其所含元素的矿化无机盐以及新的生物喷塑料。     

国际要闻

在第十三届国际塑胶展览会上德国莱芬豪舍（Reifenhauser）机械公司提供的挤出发泡工艺和产品专利，采用6层共挤发泡PP片材（其中有阻透层，粘结层和密封层）生产设备，采用了烷或戊烷为发泡剂，发泡密度为0．Zg／Cm3，6层片材总密度为O．3g／cm3。而传统发泡PP系用化学发泡剂，密度为0．5g／cm3，然后再进行薄膜复合，总体密度为O．6－07g／Cm3，经双螺杆挤出发泡的共挤片材其结构为发泡PP／粘结层／EVOH（或尼龙）阻隔层／粘结层／IJIDPE（或LDPE）密封层，发泡PP是用直径85nun同向双螺杆挤出机生产，挤出机机筒上有气体注入…     

共聚物电解质MA－Na_2／AA－Na水溶液的粘度特性

对共聚物电解质ＭＡ－Ｎａ２（顺丁烯二酸钠）／ＡＡ－Ｎａ（丙烯酸钠）水溶液ηＳＰ／Ｃ（比浓粘度）与浓度的关系、中性盐及溶液ｐＨ对ηＳＰ／Ｃ的影响进行了研究。结果表明，稀释ＭＡ－Ｎａ２／ＡＡ－Ｎａ溶液时，ηＳＰ／Ｃ急剧上升，而稀释含中性盐（ＫＣｌ或ＣａＣｌ２）的ＭＡ－Ｎａ２／ＡＡ－Ｎａ溶液体系时（中性盐含量保持０．０１ｍｏｌ／Ｌ），ηＳＰ／Ｃ的变化却不大。添加极少量（＜０．０５％）中性盐，可使ＭＡ－Ｎａ２／ＡＡ－Ｎａ溶液体系的ηＳＰ／Ｃ大幅度下降，当中性盐浓度大于０．０５％时，ηＳＰ／Ｃ趋于稳定。溶液ｐＨ＝８时，ηＳＰ／Ｃ最高，ｐＨ＜８或ｐＨ＞８时，ηＳＰ／Ｃ迅速降低。     

HPVC／PP共混改性研究：IV共混物的流变特性

研究了ＨＰＶＣ／ＰＰ共混物的流变性能，结果表明，ＣＰＥ，ＡＢＳ对ＨＰＶＣ／ＰＰ有增粘作用，随着ＣＰＥ用量增加，共混物熔体粘度（η）增加。ＣＰＥ或ＡＢＳ先与ＨＰＶＣ共混后再与ＰＰ共混的共的的η高于ＣＰＥ或ＡＢＳ先与ＰＰ共混后再与ＨＰＶＣ共混的共混物ηＨＰＶＣ／ＰＰ，ＨＰＶＣ／ＰＰ／ＭＡＨ２．５ＨＰＶＣ／ＰＰ／ＣＰＥ１０，ＨＰＶＣ／ＡＢＳ１０共混物的η～组成（Ｃ）的关系均属于正－负偏离共混物（Ｐ－ＮＤ     

疲劳/蠕变复合作用下聚苯乙烯的交互损伤研究

探讨了在疲劳／蠕变复合作用下聚苯乙烯的损伤交互作用，结果表明，在疲劳／蠕变复合作用下聚苯乙烯存在疲劳和蠕变的交互损伤，其断裂寿命比纯疲劳或纯蠕变的断裂寿命低；断裂机制是疲劳循环载荷松动和活化了分子链或链段，从而促进蠕变运动和断裂，并且，疲劳／蠕变的交互损伤程度与温度密切相关。     

共混合金力学性能的研究：Ⅱ.CPE,ACR对PVC共混体系力？…

在上文的基础上，对ＰＶＣ／ＣＰＥ／ＰＰ和ＰＶＣ／ＡＣＲ／ＰＰ三元共混体系的力学性能进行研究。结果表明，随着ＣＰＥ或ＡＣＲ用量的增加，不但共混合金的冲击强度增加，而且共混合金由刚性体ＰＰ增韧时所产生的最大值的幅度也有所提高，其趋势是ＣＰＥ或ＡＣＲ用量越多，产生最大值时刚性体分散相ＰＰ所需的量越多，同时冲击强度最大值增加的幅度也越大。     

意大利拟禁止生产、进口、销售和使用某些芳香剂

意大利卫生部于2010年9月24日发布了G／TBT／N／I—TA／19号通报。标题：技术法规草案规定：“禁止生产、进口、销售和使用脂肪族亚硝酸烷基酯、环或杂环及其异构体，以及混合成分或商品（芳香剂）”。     

几何量检测中的常用原则

设计或选择几何量检测方法时，遵守一些普遍适用的原则可减少误差或提高经济性。首先，要根据被测尺寸或要素选择一个适当的标准。为使检测误差在零件的整个制造误差中只占较少的比例，即使是高精度的测量一般必要求测量不确定度小于零件制造公差的1／3－l／5。这样，检测误差与加工误差等其它误差合成时所占比例将小于1／9－l／25；在考虑检测方法的结构布局时应遵守阿贝原则，就是要使标准与被测长度处在一条线上，这样可使工作台或测量部件移动时其不直度造成的误差减至最小。此外还应使测量链减到最短，可减少各环节变动造成的误差；在…     

Modification of oxidized graphite edge surface with poly(vinyl chloride)

An oxidized edge surface of pyrolytic graphite (PG) has been prepared by electrochemical treatment. A thin layer of poly(vinyl chloride) (PVC) was coated on the oxidized edge surface, and the PVC-coated sample heat treated at 300, 400, and 500 °C, respectively. The influence of the PVC coating on the structural change of the oxidized edge surface of PG caused by the heat treatment was studied by laser Raman and Fourier transform-infrared attenuated total reflection spectroscopies. For the electrochemical treatment, the formation of oxygen-containing functional groups proceeds over the edge surface of PG. With increasing degree of oxidation, the functional groups are formed in the following order; hydroxyl groups, carboxyl groups, lactone groups, quinones, and acid anhydrides. Acid anhydrides are formed on the outermost surface and completely eliminated by heat treatment up to 300 °C. The other functional groups remain even after heat treatment up to 500 °C. However, the functional groups are eliminated by the PVC coating, the elimination temperature depending on the type of functional groups: quinones, lactone groups, and carboxyl groups are eliminated at 300, 400, and 500 °C, respectively. PVC coated on the edge surface is found to play an important role in the complete elimination of oxygen-containing functional groups with >C=O through heat treatment at 500 °C.     

Ants work harder during consensus decision-making in small groups

Individuals derive many benefits from being social, one of which is improved accuracy of decision-making, the so-called ‘wisdom of the crowds’ effect. This advantage arises because larger groups can pool information from more individuals. At present, limited empirical data indicate that larger groups outperform smaller ones during consensus decision-making in human and non-human animals. Inaccurate decisions can lead to significant costs, and we might therefore expect individuals in small groups to employ mechanisms to compensate for the lack of numbers. Small groups may be able to maintain decision accuracy if individuals are better informed than those in larger groups and/or by increasing the proportion of the group involved in collective decision-making relative to larger groups. In this study, we use interactive computer vision software to investigate individual contributions to consensus decision-making during house-hunting in different sized groups of the ant Myrmecina nipponica. We show that individuals in small colonies invest greater effort in the consensus decision process than those in large colonies and should be better informed as a result. This may act to ameliorate the limitations of group size, but could leave smaller groups more susceptible to additional stresses.     

Effect of the carboxylic acid groups on water sorption, thermal stability and dielectric properties of polyimide films

Films from copolyimides containing side carboxylic acid groups were prepared in -COOH and COO⁻Na⁺ forms to study the effect of the side groups content on some physical properties such as water absorption, thermal stability and electrical parameters. The thermal stability was evaluated by TGA and the results showed that degradation temperatures depended not only on the side groups content but also on the membrane ionic form. This dependence was also observed in the water sorption isotherms; the polyimides with the highest -COOH content showing the highest water sorption in the equilibrium. Dielectric impedance measurements revealed how the side groups and their ionic form affect the material electrical characteristics, in such a way that resistivity decreased and permittivity increased on introducing more -COOH groups in the polymer, which is also related to a higher water uptake of the films.     

Lysosomal pH-inducible supramolecular dissociation of polyrotaxanes possessing acid-labile N-triphenylmethyl end groups and their therapeutic potential for Niemann-Pick type C disease

Niemann-Pick type C (NPC) disease is characterized by the accumulation of cholesterol in lysosomes. We have previously reported that biocleavable polyrotaxanes (PRXs) composed of β-cyclodextrins (β-CDs) threaded onto a linear polymer capped with bulky stopper molecules via intracellularly cleavable linkers show remarkable cholesterol reducing effects in NPC disease patient-derived fibroblasts owing to the stimuli-responsive intracellular dissociation of PRXs and subsequent β-CD release from the PRXs. Herein, we describe a series of novel acid-labile 2-(2-hydroxyethoxy)ethyl group-modified PRXs (HEE-PRXs) bearing terminal N-triphenylmethyl (N-Trt) groups as a cleavable component for the treatment of NPC disease. The N-Trt end groups of the HEE-PRXs underwent acidic pH-induced cleavage and led to the dissociation of their supramolecular structure. A kinetic study revealed that the number of HEE groups on the PRX did not affect the cleavage kinetics of the N-Trt end groups of the HEE-PRXs. The effect of the number of HEE groups of the HEE-PRXs, which was modified to impart water solubility to the PRXs, on cellular internalization efficiency, lysosomal localization efficiency, and cholesterol reduction ability in NPC disease-derived fibroblasts (NPC1 fibroblasts) was also investigated. The cellular uptake and lysosomal localization efficiency were almost equivalent for HEE-PRXs with different numbers of HEE groups. However, the cholesterol reducing ability of the HEE-PRXs in NPC1 fibroblasts was affected by the number of HEE groups, and HEE-PRXs with a high number of HEE groups were unable to reduce lysosomal cholesterol accumulation. This deficiency is most likely due to the cholesterol-solubilizing ability of HEE-modified β-CDs released from the HEE-PRXs. We conclude that the N-Trt group acts as a cleavable component to induce the lysosomal dissociation of HEE-PRXs, and acid-labile HEE-PRXs with an optimal number of HEE groups (4.1 to 5.4 HEE groups per single β-CD threaded onto the PRX) have great therapeutic potential for treating NPC disease.     

Italian sociologists: a community of disconnected groups

Examining coauthorship networks is key to study scientific collaboration patterns and structural characteristics of scientific communities. Here, we studied coauthorship networks of sociologists in Italy, using temporal and multi-level quantitative analysis. By looking at publications indexed in Scopus, we detected research communities among Italian sociologists. We found that Italian sociologists are fractured in many disconnected groups. The giant connected component could be split into five main groups with a mix of three main disciplinary topics: sociology of culture and communication (present in two groups), economic sociology (present in three groups) and general sociology (present in three groups). By applying an exponential random graph model, we found that collaboration ties are mainly driven by the research interests of these groups. Other factors, such as preferential attachment, gender and affiliation homophily are also important, but the effect of gender fades away once other factors are controlled for. Our research shows the advantages of multi-level and temporal network analysis in revealing the complexity of scientific collaboration patterns.

     

后接枝法合成氨丙基修饰的周期性介孔氧化硅材料

以三氯甲烷为溶剂, 氨丙基三甲氧基硅烷(APTMS)为修饰剂通过后接枝法对周期性介孔氧化硅材料(PMOs)进行修饰. 通过固态NMR、氮气吸附、元素分析和UV-vis吸光度测试等手段来表征材料. 结果表明, 氨丙基基团通过共价连接的方式成功修饰到PMOs材料. 尽管随着APTMS修饰量的增加, 比表面积、孔容和孔径都呈下降趋势, 但经25%APTMS修饰的PMOs材料依然具有良好的介孔结构, 其表面积为604m²·g^-1, 孔容为0.62cm³·^-1, 孔径狭窄分布在4.5～5.0nm之间. 修饰后的PMOs对氯金酸有明显的吸附作用.     

Effect of substituted alkyl groups on textural properties of ORMOSILs

A series of organically modified silica gels (ORMOSILs) with different alkyl groups such as methyl, ethyl, propyl, phenyl and octyl groups was investigated to determine the effect of substituted alkyl groups on the textural properties such as surface area, total pore volume, microporosity and hydrophobicity. Gelation time increased with increasing volume of alkyl groups. As-synthesized xerogels showed a systematic decrease in surface areas and total pore volumes and increase in microporosities with an increase in the volume of alkyl groups. All the ORMOSILs exhibited similar surface areas and total pore volumes after calcination at 500°C for 1 d. Increase in microporosities was observed in all the calcined xerogels. This study suggests that the primary particle sizes of pure silica cores are not affected by the size of the alkyl group, while their connectivity decreases with increasing volume of alkyl groups in the acid–base catalysed system of alkyltrimethoxysilane–tetramethylorthosilicate.     

Immobilization of the cell-adhesive peptide Arg–Gly–Asp–Cys (RGDC) on titanium surfaces by covalent chemical attachment

Surface modification of acid-pretreated titanium with 3-aminopropyltriethoxylsilane (APTES) in dry toluene resulted in covalently bonded siloxane films with surface coverage that was relatively controllable by regulating the reaction conditions. A hetero-bifunctional cross-linker, N-succinimidyl-3-maleimidopropionate (SMP), reacted with the terminal amino groups, forming the exposed maleimide groups. Finally, a model cell-binding peptide, Arg–Gly–Asp–Cys (RGDC), was immobilized on the surface through covalent addition of the cysteine thiol groups to the maleimide groups. X-ray photoelectron spectroscopy, radiolabelling techniques, and ellipsometry were used to quantify and characterize the modified surfaces.     

Prefix-Rewriting on Context-Free Groups

 A class of groups that has received much attention is the class of context-free groups. This class of groups can be characterized algebraically as well as through some language-theoretical properties as well as through certain combinatorial properties of presentations. Here we use the fact that a finitely generated group is context-free if and only if it admits a finite complete presentation of a certain form that we call a virtually free presentation. It is known that the generalized word problem for context-free groups is decidable. Here we show how prefix-rewriting systems can be used to solve this problem. In fact, we show that the Knuth-Bendix completion procedure always terminates when applied to prefix-rewriting systems on virtually free presentations of context-free groups. In addition, we present a specialized completion algorithm for prefix-rewriting systems on virtually free presentations which has polynomial-time complexity. Thus, the uniform generalized word problem for virtually free presentations of context-free groups is decidable in polynomial-time. Since finitely generated subgroups of context-free groups are again context-free, they admit presentations of the same form. We present a polynomial-time algorithm that, given a virtually free presentation of a context-free group G and a finite subset U of G as input, computes a virtually free presentation for the subgroup of G that is generated by U. Received: January 13, 1995; revised version: June 24, 1996