S-200径向氨合成塔使用A301催化剂模拟计算

根据我国引进的TopsφeS-200两段段间间接焕热径向氨合成塔的原有结构参数与工况条件,采用拟均相一维数学模型,模拟计算了使用A301催化剂的应用效果。S-200型径向氨合成塔在现有工况条件下使用A301型催化剂,合成塔出口氨浓度可达19.51%-21.33%,氨净值比使用A110提高1.5-2.5个百分点;最高日产合成氨可达1300t,在各种进塔气流量条件下,均可比使用A110增产10%-14%;在同样的合成氨产量条件下,循环气压缩功耗可比A110降低15%;废热锅炉的蒸汽产量可比使用A110提高15%-20%。结果表明,引进的大型合成氨厂第2次改造和催化剂更换采用A301型催化剂可以达到节能降耗和增产的目的。     

S-200型氨合成塔催化剂运行总结

总结S－200型氨合成塔催化剂的更换、还原以及运行情况。     

P(MMA-DBMEA)乳液聚合研究

甲基丙烯酸甲酯 ( MMA)在无皂乳化剂条件下 ,加入少量的功能性单体 N,N一二甲基 ,N-丁基 ,N-甲基丙烯酰氧乙基溴化铵 ( DBMEA) ,合成了稳定的 P( MMA-DBMEA)共聚物乳液 .该共聚物乳胶粒呈现单分散分布。同时用 NMR研究了共聚物 ,并对 P( MMA-DBMEA)聚合物13 C进行了全归属。     

Chitin characterization by SEM,FTIR, XRD,and 13C cross polarization/mass angle spinning NMR

The full characterization of chitin obtained from squid, shrimp, prawn, lobsters, and king crab is reported. Elemental analysis, including metals such as Ca, Mg, Zn, Cd, Hg, Cr, Mn, Cu, and Pb, was performed, which is quite relevant because the skeleton composition is slightly different for each species. The morphology was studied by means of TEM and their compositions were determined by energy‐dispersive X‐ray analysis. ¹³C cross polarization/magic angle spinning NMR was applied to determine the chemical shift of all the carbons and the difference between them. Chitin was isolated by using chemical methods, alternating hydrochloric acid and sodium hydroxide. The α‐chitin from shrimp, prawn, lobsters, and king crabs showed two signals at 73.7 and 75.6 ppm. Meanwhile, the β‐chitin from squid exhibited one signal at 75.2 ppm. FTIR studies were used to analyze α‐chitin from shrimp and β‐chitin from squid. The α‐chitin exhibited amide I vibration modes at 1660 and 1627 cm^?1, whereas the β‐chitin showed one band at 1656 cm^?1. X‐ray diffraction showed that α‐chitin is orthorhombic (a = 4.74 Å, b = 18.86 Å, and c = 10.32 Å) and β‐chitin had a monoclinic dihydrated form (a = 4.80 Å, b = 10.40 Å, c = 11.10 Å, and β = 97°). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1876–1885, 2004     

Reduced Dendritic Cells Expressing CD200R1 in Children with Inflammatory Bowel Disease: Correlation with Th17 and Regulatory T Cells

Loss of tolerance of the adaptive immune system towards indigenous flora contributes to the development of inflammatory bowel diseases (IBD). Defects in dendritic cell (DC)-mediated innate and adoptive immune responses are conceivable. The aim of this study was to investigate the expression of the inhibitory molecules CD200R1 and their ligand CD200 on DCs, to clarify the role of the DCs in the pathogenesis of IBD. Thirty-seven pediatric IBD patients (23 with Crohn’s disease (CD) and 14 with ulcerative colitis (UC)) with mean age 13.25 ± 2.9 years were included. Fourteen age-matched healthy pediatric volunteers (five males and nine females) served as a control group (HC). The percentage of CD11c⁺ myeloid dendritic cells (mDCs) and CD123⁺ plasmacytoid DCs (pDCs) expressing CD200R1 and CD200 were evaluated in peripheral blood using flow cytometry and were correlated with routine biochemical, serological markers, serum levels of cytokines and with the percentages of circulating regulatory T cells (Treg) and CD4⁺ producing IL-17 (Th17). IBD patients showed a significant decrease in the percentage of pDCs and mDCs expressing CD200R1 compared to that of HC. Patients with UC showed increased expressions of the CD200 molecule on pDCs as compared to HC. DCs expressing CD200R1 were found to be correlated positively with Treg and negatively with TH17 and erythrocyte sedimentation rate (ESR). Our findings suggest that IBD is associated with dysregulation in the CD200R1/CD200 axis and that the decrease in DCs expressing CD200R1 may contribute to the imbalance of Th17 and Treg cells and in the pathogenesis of IBD.     

Self‐Assembly Behaviors of Anionic–Cationic Binary Surfactant Systems in Poly(ethylene glycol) 200

The self‐assembly behaviors of mixtures of sodium bis(2‐ethylhexyl) sulfosuccinate (AOT) and didodecyl dimethylammonium bromide (DDAB) in polyethylene glycol 200 (PEG 200) and in water were investigated by surface tension, conductivity, steady‐state fluorescence and dynamic light scattering (DLS) methods. The results show that the oppositely charged binary surfactant system can form micelles in PEG 200; the critical micellization concentration (CMC) decreases for the binary system versus those of either surfactant alone. Although there is no charge screening in the PEG 200 system, the CMC values significantly increase and the system does not precipitate or show turbidity at any proportion of AOT to DDAB, while a multiphase composition gap exists in water due to the strong electrostatic attraction. It is speculated that the weak polarity of PEG 200, the decreased solvophobic interaction between the alkyl chain and PEG 200, and the loose structure of the resulting micelles might explain the experimental phenomena. Observed from the values of the interaction parameter, it is found that there are a strong attractive interaction and a synergistic effect between AOT and DDAB in aqueous solution, in comparison, the synergy between them in PEG 200 is very weak.     

玉米秸秆木质素降解过程的CP/MAS 13CNMR和SEM表征

利用黄孢原毛平革菌对玉米秸秆木质素进行降解处理,通过CP/MAS 13 CNMR和SEM研究降解过程中木质素的结构变化。CP/MAS 13 CNMR结果表明:玉米秸秆木质素降解过程中,作为木质素结构单元主要连接方式的β-O-4键基本上没有被降解;木质素单位苯环的甲氧基含量稍有增加;S/G值降低,推断反应过程中紫丁香基优先参与反应。SEM结果表明:降解后的木质素空穴增多且增大、颗粒物质减少,主要是由于酶解木质素中大量碳水化合物的降解所致;比木质素更容易降解的纤维素和半纤维素也存在于样品中。CP/MAS 13 CNMR为木质纤维原料结构的定性和初步定量提供了可能,是传统定量表征手段的有力补充,具有一定的研究意义。     

一类具强内射的正则环

研究了正则环与强CP-内射环的等价关系,证明了当R为MELT环时,R的正则性与弱正则性是等价的,同时证明了当R为约化环时,R的正则性与强CP-内射性的等价关系,并得出了当R为半本原左拟-duo环时,R的正则性、弱正则性与强CP-内射性是等价的.     

Photocurrents and degradation rates on particulate TiO2 layers: Effect of layer thickness, concentration of oxidizable substance and illumination direction

Different routes for immobilization of TiO₂ on conducting substrates were compared to find active and stable photocatalysts, which could either be operated in open circuit (photocatalysis) or with applied electric potential (photoelectrocatalysis). The advantage of applying an electric potential was investigated. Polarization curves and photoelectrochemical degradation reactions served to characterize catalysts and to find a way of predicting the optimum synthesis conditions. The difference between front side (EE) and back side (SE) illumination is discussed as a function of layer thickness, as well as the influence of oxidizable substance concentration on photocurrents. Stability of catalysts was investigated in repetitive degradation experiments.     

电镀企业清洁生产审核第二部分电镀企业如何开展清洁生产审核

对《清洁生产审核暂行办法》进行了说明,指出企业领导的重视和全体员工的参与是企业开展清洁生产审核取得成效的重要前提,明确了企业开展清洁生产审核的工作步骤和工作内容。