Electrochemical polymerization of toluene in the mixed electrolytes of boron trifluoride diethyl etherate and trifluoroacetic acid

Poly(methylphenylene) (PMeP) films were prepared by direct oxidation of toluene in the mixed electrolytes of boron trifluoride diethyl etherate (BFEE) and trifluoroacetic acid (TFA). The oxidation potential of toluene in pure BFEE was measured to be 1.52 V versus saturated calomel electrode (SCE). This value was much lower than that determined in a neutral medium such as acetonitrile (2.13 V versus SCE). The introduction of TFA into BFEE decreased the oxidation potential of toluene and also improved the properties of as‐formed polymer films. Infrared and Raman spectra confirmed the formation of PMeP films. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 189–195, 2004     

盐酸克林霉素合成工艺改进

采用新工艺合成克林霉素,流程短,收率高,重量收率比传统工艺提高了21.55个百分点,可达88.0%,产品质量符合中国药典2000版标准.     

Manipulating the phase morphology in PPS/PA66 blends using clay

By adding a small amount of clay into poly(p‐phenylene sulfide) (PPS)/polyamide 66 blends, the morphology was found to change gradually from sea–island into cocontinuity and lamellar supramolecular structure, as increasing of clay content. Clay was selectively located in the PA66 phase, and the exfoliated clay layers formed an edge‐contacted network. The change of morphology is not caused by the change of volume ratio and viscosity ratio but can be well explained by the dynamic interplay of phase separation between PPS and PA66 through preferential adsorption of PA66 onto the clay layers and through layer–layer repulsion. This provides a means of manipulating the phase morphology for the immiscible polymer blends. The mechanical and tribological properties of PPS/PA66 blends with different phase morphologies (different clay contents) were studied. Both tensile and impact strength of the blends were found obviously increased by the addition of clay. The antiwear property was greatly improved for the blends with cocontinuous phase form. Our work indicates that the phase‐separating behavior of polymer blends contained interacting clay can be exploited to create a rich diversity of new structures and useful nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Structure Aware Visual Cryptography

Visual cryptography is an encryption technique that hides a secret image by distributing it between some shared images made up of seemingly random black‐and‐white pixels. Extended visual cryptography (EVC) goes further in that the shared images instead represent meaningful binary pictures. The original approach to EVC suffered from low contrast, so later papers considered how to improve the visual quality of the results by enhancing contrast of the shared images. This work further improves the appearance of the shared images by preserving edge structures within them using a framework of dithering followed by a detail recovery operation. We are also careful to suppress noise in smooth areas.     

两步法合成大粒径丁苯胶乳

研究了聚甲基丙烯酸甲酯（MMA）对丁苯（BS）胶乳的附聚作用以增大丁苯胶乳粒径；探讨了无机盐、体系pH值及体系中MMA胶乳与BS胶乳的固含量比（R值）对附聚后丁苯胶乳的粒径及稳定性的影响。结果表明：适当添加无机盐可以稳定胶乳体系，最佳用量（质量分数）为0．1％～0．2％；适当增大体系pH值，可增大胶乳粒径；在附聚过程中，当R值在两个附聚峰附近时，可增大丁苯胶乳的粒径。     

建筑卫生陶瓷行业发展战略选择

通过对佛山、东莞等地的陶瓷产区相关企业的调查研究,在SWOT分析的基础上,研究了相关的竞争战略,归纳总结出现阶段适合建筑卫生陶瓷企业的战略:即以低成本为竞争生存方式,差异性为竞争发展动力,国际化为发展长期最终目标。     

NDN-1型氮氧化物脱除催化剂的评价及应用

对NDN-1型氮氧化物脱除催化剂进行了实验室性能评价,并与进口催化剂A及国产催化剂B进行了比较,结果表明,NDN-1型催化剂的化学组成、结构、性能均优于进口催化剂A。介绍了该催化剂在南京帝斯曼东方化工有限公司工业应用的情况。     

直播稻田化学除草试验

直播稻田用不同药剂在播种后各一次化除或播种后两次化除都具有很好的除草效果。播后前期是化学除草的关键时期播后前期每６６７米＾２用１０％苄嘧黄隆１５克＋６０％丁划胺６０毫升，１０％苄嘧黄隆１５克＋５０％杀草丹１５０毫升，１７．２％新幼禾葆２４０克或１５．８％幼禾葆２００克防铲均较好。     

Experimental investigation on possibility of oxygen enrichment by using gradient magnetic fields

This paper presents a novel method that uses the interception effect of gradient magnetic field on oxygen molecules to realize enrichment. The use of two opposite magnetic poles of two magnets at a certain distance forms a magnetic space having a field intensity gradient near its borders. When air injected into the magnetic space outflows from the magnetic space via its borders, oxygen molecules in the air will experience the interception effect of the gradient magnetic field, but nitrogen molecules will outflow from the magnetic space without hindrance. Thus, continuous oxygen enrichment is realized. The enrichment degree of oxygen reaches 0.65% when the inlet and outlet air flows are 40 mL/min and 20 mL/min, respectively, and the gas temperature is 298 K and the maximal product of magnetic flux density and its gradient is 563 T²/m (the distance between two magnetic poles is 1 mm). When the gas temperature rises to 343 K, the enrichment degree drops to 0.32%; and when the maximal product of magnetic flux density and field intensity gradient drops to 101 T²/m (the distance between two magnetic poles is 4 mm), the enrichment degree drops to 0.23%. The experimental results show that there is an optimal ratio between the inlet air flow and the outlet air flow. Under the experimental conditions in this paper, the value is about 2.0. It is demonstrated that the method presented in this paper can continuously enrich oxygen and has a higher enrichment degree than other oxygen-enrichment methods using magnetic separation. Translated from Journal of Beijing University of Chemical Technology, 2006, 33(5): 62–66 [译自: 北京化工大学学报]