纺丝组件清洗废硝酸的回收及综合利用

本文通过对ＤｕｐｏｎｔＤＭＦ二步法干纺腈纶生产过程中纺组件酸洗过程的理论分析和实际试验，提出了纺丝组件清洗废硝酸回收及综合利用的几种方法。     

DMF一步法腈纶考察及引进思考

介绍了ＳＮＩＡ公司ＤＭＦ一步法腈纶生产工艺现状及技术特色，对我国引进ＤＭＦ一步法腈纶生产工艺进行了分析，提出不应排除ＤＭＦ一步法技术，可选择少数厂家适当引进该技术，使我国最终形成４～５种工艺并存的格局。     

干纺腈纶制条工艺探讨

干纺腈纶因其纺丝成形工艺特殊，纤维结构致密，截面呈犬骨状，因而与湿纺腈纶有不同特点。研究干纺腈纶制条工艺对指我国干纺腈纶后加工及应用具有重要意义。     

意大利DMF一步法腈纶湿纺技术简介

意大利ＤＭＦ一步法腈纶湿纺技术简介陈明仁，瞿彩芝（金陵石化公司腈纶筹建办南京，２１００４２）腈纶是所有合成纤维中工艺路线最多的品种，其工业化路线达１２种之多￣［１］。我国腈纶生产在１９８５年以前一直以ＮａＳＣＮ一步法工艺为主，在“七五”期间，为改善我...     

干纺腈纶工艺及纤维特性

<正> 一 干纺腈纶概况 腈纶根据其纺丝成形方式不同分为干纺腈纶和湿纺腈纶两大类型。干纺腈纶是世界最早工业化生产的腈纶品种,目前,干纺腈纶产量约占世界腈纶总产量的20％左右,主要集中在美国Du pont、西德Bayer及Hoechst、奥地利Lenzing等几家公司之中。Du pont、Bayer是世界干纺腈纶的主要代表,产量分别约占本国腈纶总产量的36％和86％,产     

DMF市场供需缺口大

据了解，由于农药杀虫脒残留物中有致癌物质存在，因而我国ＤＭＦ在农药方面的市场将逐渐消失。但在医药、聚丙烯腈抽丝、聚氨酯合成革等领域的消费量却有很大的增长。预计今年我国ＤＭＦ的总需求量将达到约３．１万吨，但实际年产量仍不足２万吨，远远不能满足国内市场需求，供需缺口较大，开发前景十分乐观。 以ＤＭＦ为溶剂的聚丙烯腈抽丝工艺生产的腈纶产品，具有疏水性好、覆盖性强、质地柔软、毛感强等特点。目前我国聚丙烯腈抽丝总生产能力为１６．５万吨／年，需耗ＤＭＦ８２５０吨，预计今年的需求量将达１．４５万吨。 ＤＭＦ在湿…     

干纺腈纶拉断法制条工艺探讨

分析比较了干纺与湿纺腈纶丝束的性能,通过对干纺与湿纺腈纶丝束拉断法制条工艺的比较,论述了干纺腈纶丝束制条工艺参数确定的依据和生产技术关键。     

腈纶生产工艺第五讲二甲基甲酰胺一步法

腈纶生产工艺第五讲二甲基甲酰胺一步法汪维良，任铃子，王精铎（中国石化总公司发展部，北京，１０００２９）（上海石化股份有限公司，２００５４０）（山东淄博合成纤维厂，２５５０３０）二甲基甲酰胺（ＤＭＦ）一步法腈纶湿纺工艺由意大利斯尼亚公司（Ｓｎｉａ）首先...     

高收缩干纺腈纶毛条生产工艺探讨

通过改变干纺腈纶生产工艺条件，生产出高收缩腈纶长丝束，然后经拉断制条，制成收缩率为２５％的高收缩率混旦毛条，并分析探讨了腈纶长丝束质量及拉断机拉伸条件对毛条收缩率的影响。     

MDF水泥的微观结构和断口分析

应用ＳＥＭ／ＥＤＡＸ、ＳＴＥＭ等仪器比较详细地研究了ＭＤＦ水泥及其断口的微观结构。实验结果表明，ＭＤＦ水泥是由聚合物粘结水泥颗粒构成的新型材料。水泥－聚合物界面粘结良好，界面基本上没有孔隙。聚合物具有较高的孔隙卒，多孔的聚合物是材料的薄弱环节和断裂通道。聚合物的孔隙率和聚合物掺量是影响ＭＤＦ水泥抗弯强度的重要因素。在断裂过程中ＭＤＦ水泥中聚合物具有较高的断裂韧性和断裂伸长。同时探讨了高强ＭＤＦ水泥的结构特征和断裂机理。     

The annual cycle of Flehmen in black-tailed deer (Odocoileus hemionus columbianus)

Flehmen is a stereotyped response of ungulates and other mammals to urine. In black-tailed deer, Flehmen occurs typically in males (rarely in females), and its frequency shows an annual cycle. Flehmen in response to female urine was most frequent in November, and to male urine in January. The response minimum to both types of urine occurred in May. Fifty-five to 100% of initial responses to female urine resulted in Flehmen. The deer responded more often to female urine, and the difference between the responses to female and male urine increased from May to November. A male's own urine released Flehmen more often than did urine of other males. The response intensity varied with the spatial orientation of the male to the urinating female, and responses were usually limited to distances of 15 m or less.     

Adhesives in construction: A contractor's viewpoint

The development of epoxy- and polyester-based adhesives has dramatically widened the scope of adhesive bonding in the civil engineering industry but the technology of the adhesives used has often been more appropriate to the workshop than to the construction site. There is a need for the suppliers of structural adhesives to recognize this and to develop compositions and application techniques more amenable to site use. It is equally necessary for the construction industry to make more effort to understand these materials, to take advantage of their outstanding properties, and hence to use them successfully for the construction and repair of concrete structures.     

绿色环保意识的趋向

随着消费者环保意识的提高,人们除了认清绿色环保能对社会和全世界起到巨大的促进作用,还认为绿色环保能够直接、积极地反映其社会地位,在某种程度上反映出消费者自己的绿色环保意识。介绍了消费者对"绿色化"的认识,对"绿色产品"的期望以及生产厂家对"绿色原料"的认证和对"可持续发展"所做的贡献。     

Modelling titania formation at typical industrial process conditions: effect of surface shielding and surface energy on relevant growth mechanisms

This work investigates the effects of reduced accessible surface area of aggregate particles and of surface energy on relevant particle formation and growth mechanisms during titania formation from the vapour phase at industrial process conditions. Growth due to surface reaction and due to condensation is related to the fraction of the surface area that is exposed to the collision with single molecules. Surface shielding is found to hamper surface reaction and condensation once fractal aggregates start to form. It leads to significantly retarded precursor consumption and produces aggregate particles, which consist of more, but smaller primary particles. Surface energy data are varied within a range as proposed by available literature data. Moderate and high surface energy values result in a thermodynamic barrier to the formation of new particles and are shown to reduce the formation of seed particles by several orders of magnitude. This leads to the formation of aggregate particles which consist of a rather small number of primary particles and mainly grow by surface reaction. The primary contribution of condensation to growth of individual primary particles is shown to be very little. However, condensation should not be neglected as it has a strong impact on particle formation rates and hence on product characteristics such as the number of primary particles and primary particle size.     

Atomic and micro-structure features of nanoporous aluminosilicate glasses from reactive molecular dynamics simulations

Long-term chemical durability of borosilicate glasses that makes them a widely accepted form of nuclear waste disposal is achieved through the formation of a porous aluminosilicate gel layer that provides passivity and limits the transport of water to the reaction front. Detailed understanding of the porous silicate gel layer is thus critical in elucidating the corrosion mechanism of these glasses and to design of new glass composition for waste immobilization and other applications. In this paper, we use the diffuse charge reactive potential to generate porous aluminosilicate glass structures with compositions equivalent to the gel layers formed at the glass-water interface with an aim to understand the processing condition on the microstructure and atomic structure of these systems. We demonstrate the use of the charge scaling techniques is an effective approach to generate these porous structures with controllable pore mophologies. After initial validation of the potentials and calcium aluminosilicate glass structures using neutron diffraction, we created gel structures with compositions similar to well-known model nuclear waste borosilicate glasses. The porosities and the pore size distribution bear a strong correlation to the processing temperature, as well as to the local atomic structure. Thus, by controlling the processing parameters, the generated porous structures can be customized to closely resemble gel structures due to borosilicate glass corrosion. These results provide insights of the micro- and atomic structure features of the porous aluminosilicate glasses and on the optimal procedure to generate porous structures that can be comparable to experimentally observed gel layer structures thus to elaborate on the correlations between the structure and phenomena in glass-water interactions.     

Long-term residual value of North Carolina and Queensland rock phosphates compared with triple superphosphate

The effectiveness of large single applications of North Carolina reactive rock phosphate, Queensland non-reactive rock phosphate, and Calciphos, were compared to the effectiveness of superphosphate in field experiments in south-western Australia for up to 11 years after application. As measured using plant yield, superphosphate was the most effective fertilizer in the year of application, and relative to freshly-applied superphosphate, the effectiveness of the superphosphate residues declined to be about 15 to 65% as effective in the year after application, and 5 to 20% as effective 9 to 10 years after application. Relative to freshly-applied superphosphate, all the rock phosphates were 10 to 30% as effective in the year of application, and the residues remained 2 to 20% as effective in the 10 years after application. The bicarbonate soil test reagent predicted a more gradual decrease in effectiveness of superphosphate of up to 70% 10 years after application. For rock phosphate, the reagent predicted effectiveness to be always lower than for superphosphate, being initially 2 to 11% as effective in the year after application, and from 10% to equally as effective 10 years later. Therefore rock phosphates are unlikely to be economic alternatives to superphosphate in the short or long term on most lateritic soils in south-western Australia.     

Organic Synthesis: Wherefrom and Whither? (Some Very Personal Reflections)

This perspective represents a (highly personal) examination of the past, present and future of synthetic organic chemistry. The central thesis posits that the confluence of factors that led to the “Golden Age of Natural Product Synthesis” in the second half of the twentieth century can be traced back to the identification of the therapeutic potential of steroid hormones culminating in the introduction of oral contraceptives. The tremendous benefits of those activities to the development of organic synthesis as a vibrant discipline led to the exponential increase in strategies and methods and the ability to tackle, larger and larger molecules of greater and greater complexity. The existential challenge to the health of organic synthesis is whether a similarly dynamic future can be anticipated and if so, to what end and how. Musings on potential answers to those questions are presented.     

高效、清洁、高附加值原则指导下适度、有序发展煤化工产业

针对我国可持续发展面临的能源瓶颈,指出适度、有序发展煤化工产业是我国现有能源结构环境下的必然选择。在低碳理念指导下,提出了煤炭资源的分质利用原则、高能效利用原则、综合利用原则、因地制宜利用原则和高附加值利用原则,比较分析了煤的各种化学转化途径,阐述了含氧醇醚材料替代石油路线、煤制芳烃、煤/天然气/煤层气制备乙炔等具有前景的清洁、高效转化过程,期望为煤化工产业的健康、有序发展提供科学思路。     

Use of lipases in multiphasic systems solely composed of substrates

Three lipase-catalyzed reactions have been investigated in relation to specificity and water dependence. The reactions in question include: the synthetic reaction between oleic acid and glycerol; the enzymatic hydrolysis of triolein; and alcoholysis/glycerolysis transesterification reactions. All reactions were carried out under solventfree conditions. In each case, the medium composition and reaction conditions were optimized in order to work at elevated substrate concentrations and to minimize the production of by-products. Different lipase preparations have been tested in each reaction. In the synthetic reaction, the effective removal of produced water was found to be vital for the production of triolein. With water removal and glycerol amounts not higher than required by the stoichiometry of the reaction, 95% of the available oleic acid was converted to triolein in 48 hr. The production of triolein was also found to be dependent on the availability of the 1,2-diglyceride to react with oleic acid. In the hydrolysis reaction, best conversion yields of triolein towards monoolein, diolein and free fatty acid were obtained when water was considered simply as a substrate of the reaction. In glycerolysis reactions, the reaction of triolein to give monoolein and diolein followed much the same pattern as for hydrolysis, when water was replaced by glycerol. It was shown again that near stoichiometric amounts of substrates led to the best conversion to mono- and diglycerides. A small excess of glycerol was found to be very inhibitory to the reaction. All possible isomers were formed during the reaction. Conversely, in alcoholysis reactions between triolein and stearyl alcohol the specificity of the lipase was upheld. Excess alcohol in this instance was found to be beneficial.