丁二烯罐车卸车的新工艺

丁二烯罐车卸车多要用氮气注入罐车加压,同时用离心泵抽液的卸车方法,该方法存在氮气耗费量大,费用高,污染环境等问题。通过对四种卸车方式的比选,采用热水换热器给丁二烯加热使之气化的方法,从加入阻聚剂,清除活性剂,降低氧含量,控制温度几方面入手,有效地控制丁二烯自聚物的产生,收到了较好经济效益和社会效益。     

丁二烯系统爆炸原理及防止方法

论述了丁二烯系统突然自动爆炸的原因，是因为有氧气进入了系统，形成了丁二烯过氧化合物，并用实验进行了验证，分析了丁二烯过氧化物的组成，用键能法计算了爆炸反应能量，提出了预防爆炸发生的方法。     

基于自组织竞争神经网络的红籽瓜自交系聚类分析

自组织竞争神经网络是一种具有强大的自学习功能、良好的自组织性和自适应性的聚类方法,能够迅速得到聚类结果.本文基于自组织竞争神经网络的聚类功能,依据6个红色籽用西瓜数量性状特征指标,将47份自交系分为4类.聚类结果表明,不同自交系类群间的遗传变异较大,在配置杂交组合时,应尽量在不同类群问选配亲本,为红籽瓜育种提供理论依据.     

合成橡胶价格反弹

<正>上周,中国石化和华东顺丁二烯橡胶的价格上扬,东部实行避险交易。丁二烯橡胶外盘稳定上升,胡椒交易受到冲击。合成橡胶市场公布舒适的外部环境,从一定程度上支撑了橡胶产业交易的信心。但未来市场还有一些变化,4月合成橡胶市场依然充满盲目乐观。     

浅谈微硅粉在自密实混凝土中的应用

微硅粉具有较好的抗分散性能，因此在自密实混凝土中掺入少量的微硅粉可以有效改善混凝土拌合物的粘聚性和流变性，简化施工工艺，并可显著提高混凝土的强度和耐久性。     

基于空间自相关分析的温瑞塘河底泥Ni、Zn空间聚类和异常值分析

将增量全局空间自相关技术和局部空间自相关技术相结合,以进一步完善环境污染的空间聚类和异常值分析方法,同时以温瑞塘河底泥Ni、Zn含量调查数据为例,展示了该方法的有效性和可靠性。结果表明,温瑞塘河流域底泥Zn和Ni的均值分别是土壤背景值的11.74和2.38倍。Zn和Ni含量呈现出显著的空间自相关性,而空间自相关性则展现出尺度效应。增量全局空间自相关分析能够确定空间自相关分析的最佳距离阈值,局部空间自相关分析能够识别出底泥重金属含量的空间聚类和异常值所在的具体位置,进而为采取针对性的污染防控决策提供科学依据。     

云台农场力做“食品安全”守护者

江苏农垦云台农场的企业质量安全文化，是云台农场人多年来生产经营沉积和塑造出的宝贵文化财富，也是今后相当长的时期内指导云台文化建设和推动云台跨越发展的内在动力。为进一步提升农产品质量安全水平和全程监管能力，农场自2007年起启动了农产品质量安全建设项目，切实有效地抓好源头农产品的质量安全工作，基本步实现了农产品质量可追溯，取得了积极成效。     

基于聚气释压实现厌氧干发酵自搅拌的模拟试验

[目的]为解决干发酵传质限制和搅拌能耗高等问题提供新思路。[方法]提出基于"周期聚气增压,瞬时释气泄压"实现自搅拌。采用空气为模拟气源,以盒子分形维数为搅拌效果定量评价指标,研究了聚气压力、释压时间、聚气空间分布对搅拌效果的影响。[结果]分形维数随聚气压力的增加而增大,当压力逐步升至0.70 MPa时,反应器纵截面分形维数相对搅拌前增加了12.06%,搅拌效果明显增加;当释压时间为0.60~0.80 s,聚气压力为0.30~0.40 MPa时,分形维数变化率达最大值0.158 4,搅拌效果最佳。[结论]聚气释压可实现干发酵自搅拌。     

联合模糊c-均值聚类模型

提出一种新的结合了模糊c-均值聚类（FCM）算法和可能性c-均值聚类（PCM）算法优点的联合模糊c-均值聚类（AFCM）算法。它克服了PCM对初始值敏感、易产生一致性聚类的缺点，是PCM的扩展算法。试验表明：AFCM能同时产生隶属度和典型值，从而更好地处理噪声，避免了一致性聚类，同时提高了聚类准确性。     

麦乐鸡产品专项调查展开国家药监局召开论证会

针对麦当劳的麦乐鸡中含有化学物质“聚二甲基硅氧烷”和“特丁基对苯二酚”，近期，北京已开展对麦乐鸡食品安全的专项调查。同时，国家食品药品监督管理局已会同有关部门，对全国麦当劳餐厅的麦乐鸡及相关产品，进行卫生安全监测。     

Surface-modified carbon nanotubes catalyze oxidative dehydrogenation of n-butane

Butenes and butadiene, which are useful intermediates for the synthesis of polymers and other compounds, are synthesized traditionally by oxidative dehydrogenation (ODH) of n-butane over complex metal oxides. Such catalysts require high O2/butane ratios to maintain the activity, which leads to unwanted product oxidation. We show that carbon nanotubes with modified surface functionality efficiently catalyze the oxidative dehydrogenation of n-butane to butenes, especially butadiene. For low O2/butane ratios, a high selectivity to alkenes was achieved for periods as long as 100 hours. This process is mildly catalyzed by ketonic CO groups and occurs via a combination of parallel and sequential oxidation steps. A small amount of phosphorus greatly improved the selectivity by suppressing the combustion of hydrocarbons.     

羧甲基淀粉胶粘剂合成工艺研究

为解决淀粉基胶粘剂胶接木质材料强度的问题,试验用羧甲基淀粉、聚乙烯醇、异氰酸酯和羧基丁苯胶乳等原料合成胶粘剂并探讨合成过程中各因素对胶接后强度的影响规律。采用二次旋转正交组合方法设计,分析了各合成因素对胶粘剂胶接木质材料后强度的影响规律,优化得到了一种具有较高胶接强度的新型羧甲基淀粉胶粘剂的合成方案。最优配方为羧甲基淀粉含量15.29%,聚乙烯醇含量6.25%,异氰酸酯含量8.61%,羧基丁苯胶乳含量2.24%,反应温度58.38℃。强度可达到4.1176Mpa,符合国家标准。     

Enantioselective C-H crotylation of primary alcohols via hydrohydroxyalkylation of butadiene

The direct, by-product-free conversion of basic feedstocks to products of medicinal and agricultural relevance is a broad goal of chemical research. Butadiene is a product of petroleum cracking and is produced on an enormous scale (about 12 × 10(6) metric tons annually). Here, with the use of a ruthenium catalyst modified by a chiral phosphate counterion, we report the direct redox-triggered carbon-carbon coupling of alcohols and butadiene to form products of carbonyl crotylation with high levels of anti-diastereoselectivity and enantioselectivity in the absence of stoichiometric by-products.     

硅烷偶联剂改性废胶粉及其在胎面胶中的应用研究

采用偶联剂Si-69改性不同目数的废胶粉,探讨改性废胶粉对天然橡胶/顺丁橡胶并用胎面胶性能的影响。结果表明,偶联剂Si-69对废胶粉的改性效果明显,其对40目和80目废胶粉的适宜用量分别为2质量份和4质量份;改性40目和80目废胶粉的用量均为10份时,胎面胶具有相对较好的综合力学性能;改性废胶粉的适量掺入能一定程度提高胎面胶的磨耗性能。     

Giant wormlike rubber micelles

A low molecular weight poly(ethyleneoxide)-poly(butadiene) (PEO-PB) diblock copolymer containing 50 weight percent PEO forms gigantic wormlike micelles at low concentrations (<5 percent by weight) in water. Subsequent generation of free radicals with a conventional water-based redox reaction leads to chemical cross-linking of the PB cores without disruption of the cylindrical morphology, as evidenced by cryotransmission electron microscopy and small-angle neutron scattering experiments. These wormlike rubber micelles exhibit unusual viscoelastic properties in water.     

Laser-induced selectivity for dimerization versus polymerization of butadiene under pressure

The pressure-induced chemical reaction of liquid butadiene was studied by Fourier transform infrared spectroscopy in a diamond anvil cell. Dimerization was found to occur above 0.7 gigapascal, giving vinylcyclohexene according to a cyclo-addiction reaction and only a trace amount of polybutadiene forms. By irradiating the high-pressure sample with a few milliwatts of the 488-nanometer argon+ laser line, the dimerization was completely inhibited, and the rapid formation of pure trans-polybutadiene was observed. The use of different excitation wavelength allows us to emphasize the selectivity of the process and to identify the active role of the 2(1)Ag state in this pressure- and laser-induced chemical reaction.     

Potential for Converting Wood into Plastics: Chemicals from wood may regain importance as the cost of petroleum continues to rise

The conversion of wood into chemicals for the production of most of our synthetic plastics, fibers, and rubbers is technically feasible. With refinements in technology a large integrated plant utilizing all components of the wood for production of ethanol (to be further processed to ethylene and butadiene), phenols and furfural would be approaching economic feasibility as well at current petrochemical prices. If crude oil prices continue to climb at a faster rate than wood costs, the economic feasibility of chemicals for polymers from wood would become certain. Although technical feasibility has not been established, synthetic oils from liquefaction of wood might serve as feedstocks for cracking to chemicals in the same way that crude oil is presently used. The fulfillment of all our polymer needs from wood as a raw material should not place an impossible burden on our wood supply, but might actually improve the availability of wood for lumber, plywood and pulp by providing a use for less valuable wood which would allow reforestation and improved forest management.     

陕西省南部地区土壤粘粒特性研究

陕西南部土壤粘粒特性的研究发现,陕西省南部北亚热带湿润地区,发育在第四纪下蜀黄土母质上的土壤粘粒含量高,粘化层不明显,粘土矿物以伊利石和蒙脱石为主,粘粒铁富集明显;发育在基岩风化物母质上的土壤粘化层明显,粘土矿物以蒙脱石、蛭石为主,且有一定量的高岭石,粘粒中铝富集强烈。中山区暖温带湿润地区的土壤,粘粒含量较低,粘土矿物以伊利石、绿泥石为主,粘粒中铁、铝富集均不明显,元素的淋溶迁移较弱。