工业有害废物填埋场渗析液处理设计

根据工业有害废物填埋场渗析液中含有多组份重金属以及水量的不连续性和出水回用的特点 ,采用化学处理法与过滤、吸附相结合的方法处理此渗析液 ,使出水达到国标“农业浇灌用水”标准的要求     

Esters of hydroxystearic acids as primary low-temperature plasticizers for a vinyl chloride—Vinyl acetate copolymer

Summary Thirty-one acyloxy or aryloxy esters prepared from hydroxystearic acids have been evaluated as plasticizers for a vinyl chloride-vinyl acetate copolymer (95∶5). Many of them were found to be primary plasticizers, having outstanding low-temperature performance when employed at the 35% level. Formulations with these compounds compared quite favorably in tensile properties with those containing the di-2-ethylhexyl esters of phthalic, sebacic, azelaic, and adipic acids. Volatility losses were similar to those of the four di-2-ethylhexyl esters. The loss of plasticizer through migration was equal to or less than that from compositions containing the esters of sebacic, azelaic, and adipic acids but was greater than that of the phthalate ester. A mechanistic scheme of plasticizer-polymer interaction has been presented, proposing that the rate of diffusion of plasticizer through the polymer mass is a controlling factor in both good low-temperature performance and the resulting high migration losses. Methyl esters, some aromatic esters, and esters containing three or more polar centers have improved permanence but show a more rapid change in torsional modulus as the temperature is lowered during the determination of the Clash-Berg stiffening temperature. Eastern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

The Effect of Aluminum Ions on the DC Etching of Aluminum Foil

A study has been made of the electrochemical etching of 99.99% aluminum foils at a current density of 50 mA cm^–2in AlCl₃–HCl solutions (1 m Cl^–) at 80 °C. The solutions were made by dissolving metallic aluminum into 1m HCl solution, to give a Cl^– concentration of 1 m. The number density of etch tunnels and the homogeneity of tunnel length decreased, and the mean pit size and its standard deviation increased with increasing Al³⁺ concentration. The results were discussed based on potential transients at a current density of 50 mA cm^–2, current–potential curves at a scan rate of 10 m Vs^–1 and electrochemical impedance spectra.     

Low‐temperature photoinitiation solution polymerization behavior of N‐vinylcarbazole in tetrahydrofuran

N‐Vinylcarbazole (VCZ) was solution‐polymerized in tetrahydrofuran (THF) at ?20, 0, and 20°C using the photoinitiation method; the effects of the amount of solvent, polymerization temperature, and photoinitiator concentration were investigated. On the whole, the experimental results corresponded to predicted ones. Low polymerization temperature using photoinitiation proved to be successful in obtaining poly(N‐vinylcarbazole) (PVCZ) of a high molecular weight with a smaller temperature rise during polymerization; nevertheless of free radical polymerization by 2,2′‐azobis(2,4‐dimethylvaleronitrile) (ADMVN). The photo‐solution polymerization rate of VCZ in THF was proportional to the 0.47 power of ADMVN concentration. The molecular weight was higher and the molecular weight distribution was narrower with PVCZ polymerized at lower temperatures. For PVCZ prepared in THF at ?20°C using a photoinitiator concentration of 0.00005 mol/mol of VCZ, a weight‐average molecular weight of 510,000 was obtained, with a polydispersity index of 1.73, and a degree of lightness converged to about 99%. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3667–3672, 2002     

运用BP网络分析尿素合成塔CO_2转化率

采用BP神经网络模型预测尿素合成塔CO_2 转化率 ,分析了氨碳比和水碳比与转化率之间的关系。详细介绍了建模过程并对隐含层神经元数和迭代次数对网络性能的影响进行了讨论。分析结果表明 :所建模型能准确地对CO_2 转化率进行预测 ,平均相对误差在 1 0 %以内 ;CO_2 转化率随氨碳比的增大而显著增加 ,水碳比的影响则相对较小。     

用混合式遗传算法进行给水管网现状分析

将广义简约梯度法(GRG)思想应用于传统遗传算法,提出一种新的混合式遗传算法(HGA),此方法具有很强的全局和局部搜索能力,并且无需复杂的编码、解码过程,可以准确解决多变量、多峰值的给水管网现状分析问题。采用此算法,绝大多数的计算值与实测值的误差可减小到1%以下,能准确反映管网的实际工况。     

Effect of hydrophobic hexafluoroisopropylidene group on the water sorption behaviors of rigid poly(p‐phenylene pyromellitimide) polyimide thin films

We prepared poly(p‐phenylene pyromellitimide) (PMDA–PDA), poly(p‐phenylene 4,4′‐hexafluoroisopropylidene diphthalimide), and their copolyimides with various compositions to explore the relationship between the water sorption and structure. The water sorption behaviors were gravimetrically investigated as a function of composition and temperature and interpreted with a Fickian diffusion model in films. Overall, the water sorption behaviors were strongly dependent on the changes in morphological structure, which originated from the variations in composition. When the content of the bulky hexafluoroisopropylidene group (6FDA) was increased, the water uptake decreased from 5.80 to 3.18 wt %, whereas the diffusion coefficient increased from 3.6 × 10^?10 to 11.3 × 10^?10 cm²/s. The relatively high water uptake in the PMDA–PDA polyimide film was successfully healed by the incorporation of 6FDA, which may have resulted from the increases in the intermolecular packing order and hydrophobicity. The degree of orientation and crystallinity, which are in‐plane characteristics, were directly correlated to the diffusion coefficient and activation energy in the polyimide film. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3442–3446, 2003     

Immobilization of a cyclodextrin glucanotransferase (CGTase) onto polyethylene film with a carboxylic acid group and production of cyclodextrins from corn starch using CGTase‐immobilized PE film

Carboxylic acid groups were introduced onto polyethylene (PE) film by radiation‐induced graft copolymerization. Subsequently, the clodextrin glucanotransferase (CGTase) was immobilized on the PE film with a carboxylic acid group. The activity of the immobilized CGTase on PE film was in the range of 0.40–1.04 U/cm² per min. The production of cyclodextrins (CDs) from corn starch was examined using the CGTase‐immobilized PE film. The production ratios of CDs using CGTase‐immobilized PE film was in the following order: α–CD > β–CD > γ–CD. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2451–2457, 2002     

Numerical simulation of fixed-bed catalytic reactor for isopropyl alcohol synthesis

The mathematical model and the method of its numerical analysis for fixed-bed catalytic reactors were developed and were applied to the pilot reactor of isopropyl alcohol (IPA). The experimental results from pilot test runs were used to test and verify the simulation results. The numerical simulation gives the IPA concentration and temperature profiles in the reactor. The production of IPA from a commercialized ethanol rector was examined. The operation conditions of IPA synthesis were established.     

Diamond growth by carbon ion implantation of diamond

Medium energy (5–25 keV) ¹³C⁺ ion implantation into diamond (100) to a fluence ranging from 10¹⁶ cm⁻² to 10¹⁸ cm⁻² was performed for the study of diamond growth via the approach of ion beam implantation. The samples were characterized with Rutherford backscattering/channelling spectroscopy, Raman spectroscopy, X-ray photoemission spectroscopy and Auger electron spectroscopy. Extended defects are formed in the cascade collision volume during bombardment at high temperatures. Carbon incorporation indeed induces a volume growth but the diamond (100) samples receiving a fluence of 4 × 10¹⁷ to 2 × 10¹⁸ at. cm⁻² (with a dose rate of 5 × 10¹⁵ at. cm⁻² s⁻¹ at 5 to 25 keV and 800 °C) showed no He-ion channelling. Common to these samples is that the top surface layer of a few nanometers has a substantial amount of graphite which can be removed by chemical etching. The rest of the grown layer is polycrystalline diamond with a very high density of extended defects.