生物肥力——未来我国土壤修复的主要方式之一

根据我国耕地资源现状:耕地面积逐年减少,土壤重金属污染、酸化严重,土壤有机质含量、微生物活性下降,提出我国土壤修复刻不容缓。介绍生物肥力的起源和作用,生物肥力对修复土壤、减少重金属污染作用明显,对农药、石油污染土壤有修复作用,提出生物肥力将成为我国土壤修复的主要方式。     

腐植酸在土壤修复中的作用

目前,腐植酸对污染土壤的修复作用已经引起了人们的广泛关注。本文在介绍了腐植酸来源及其结构特点的基础上,论述了腐植酸在土壤改良、重金属污染及有毒有机污染物污染土壤修复等方面的作用。其中,腐植酸对土壤的改良作用主要包括改良土壤结构、改良盐碱地以及提高土壤肥力等;腐植酸对重金属和有毒有机污染物污染土壤的修复作用主要包括腐植酸对重金属和有机物的吸附沉淀作用、氧化还原作用以及腐植酸能够促进土壤微生物对有机污染物的降解等。最后,讨论了腐植酸在土壤修复中需要进一步加强研究的方面,为腐植酸在土壤修复中的应用提供重要参考。     

高浓度硝基苯污染土壤的淋洗试验

本文探讨了3种常用表面活性剂Triton X-100、Tween-80、SDBS对高浓度硝基苯污染土壤的修复洗脱作用以及土壤对3种表面活性剂的吸附作用。淋洗实验结果表明,3种表面活性剂对土壤中硝基苯的去除与蒸馏水相比没有明显去除效果,而且实验土壤对3种表面活性剂均有较强的吸附作用。这种吸附作用对土壤中硝基苯的去除有严重不利影响。     

腐植物质钝化和活化土壤重金属的防污染作用

叙述了腐植酸与重金属作用的机理,即腐植酸通过络合、螯合、还原作用使重金属固定在土壤颗粒表面,从而影响它们的迁移并减少了重金属水溶态,降低其毒性。介绍了腐植酸在治理土壤重金属污染中的应用和相应的净化效果以及影响腐植酸吸附重金属的因素,如土壤类型、PH值、作用时间等,并指出腐植酸在降低土壤重金属活性（毒性）作用中存在的问题及发展趋势。     

高吸水性树脂的保肥作用研究

利用化学分析法研究了高吸水性树脂对土壤中氮、磷、钾养分的影响。结果表明,聚丙烯酸钠高吸水性树脂本身对氮、磷、钾养分有较强的吸附和解吸能力,当施入土壤后．这种能力显著下降。但与土壤本身对这三种养分的作用相比,高吸水性树脂的使用,增强了土壤对氮和钾的吸附、固定及解吸;虽然对土壤吸附磷的影响并不大,但提高了土壤对磷的解吸能力,减弱了土壤对磷的固定作用,从而使磷的有效性得到提高,综合来看,聚丙烯酸钠高吸水性树脂的使用,起到了保肥和延缓肥效的作用。     

腐植酸类物质是土壤健康的重要保障

腐植酸类物质是一种具有复杂结构的功能大分子,其种类和数量对土壤质量、土壤可持续利用具有重要作用。本文从土壤肥力质量、土壤环境质量、土壤健康质量3个方面综合阐述了腐植酸类物质对于保障和维持土壤质量健康、保护人类和动植物健康的重要作用和意义,并对今后的研究方向提出了若干建议。     

电子垃圾污染土壤淋洗处理技术综述

论文是有关土壤淋洗技术的综述性论文。土壤淋洗的作用机制在于利用淋洗液或化学助剂与土壤中的污染物结合,并通过淋洗液的解吸、螯合、溶解或固定等作用,达到修复污染土壤的目的。论文对土壤淋洗技术的特点作了介绍,将其应用于处理电子垃圾污染土壤,淋洗效果优良。     

冻融作用对土壤中氨氮的影响

我国对土壤冻融作用研究主要集中在自然环境条件下冻土环境变化.本文是对齐齐哈尔市南郊污水处理厂附近的氧化塘中的冻融土壤进行研究,论述了冻融作用对土壤中氨氮的影响.研究表明,季节性冻融作用对土壤氨氮有较大影响.     

冻融作用对土壤中总磷含量的影响

我国对土壤冻融作用研究主要集中在自然环境条件下冻土环境变化。对齐齐哈尔市南郊污水处理厂附近的氧化塘中的冻融土壤进行研究,论述了冻融作用对土壤中总磷含量的影响。研究表明,季节性冻融作用对土壤总磷含量有较大影响。     

种植北五味子和土壤中微量元素的测定

研究了土壤和种植北五味子果实中微量元素的含量差异。采用梅花形布点法采样,用ICP-MS测定土壤和果实中的微量元素含量。试验地土壤中含有丰富的微量元素,其含量大小依次为:CaKMgFeMnZnCu,所测北五味子果实中微量元素含量大小依次为:KMgCaFeMnZnCu。所测北五味子对土壤中微量元素的吸收具有选择性,北五味子中K含量明显高于土壤,Cu、Cr、Fe含量明显低于土壤,说明五味子对K有富积作用,对Cu、Cr、Fe无富积作用。     

水泥水化热测定方法综述

水泥水化热是中、低热水泥和核电工程用水泥的一项关键的技术指标。全球范围内测定水泥水化热的方法有溶解法、直接法/半绝热法、等温传导量热法三种。本文总结了中、美、欧相关方法标准,对其测试原理、仪器设备、试验过程等方面进行了比对,并对其在领域的应用做了简单的概括。     

Model of Cellular Instability of Flames of Ternary Mixtures

A simple phenomenological diffusive-thermal model of cellular instability of premixed flames of ternary mixtures is developed and presented. The model shows that preferential diffusion can alter stoichiometry of the mixture, i.e., the ratio of the fuel and oxidizer concentrations, and also its effective dilution by an inert. Key parameters of the model are estimated using numerical modeling of burning velocities. Laminar burning velocities are calculated for hydrogen-oxygen-nitrogen, methane-oxygen-nitrogen, and propane-oxygen-nitrogen mixtures. Conditions for the appearance of cellular instability in ternary mixtures are determined and compared with experiments. In good agreement with experimental observations, the diffusive-thermal instability is predicted in hydrogen flames with equivalence ratios φ ≲ 1.45, in lean methane flames with φ ≲ 1.02, and in rich propane flames with φ ≳ 1.03. The magnitude of the change in the local flame velocity due to preferential diffusion is evaluated. It is demonstrated that nitrogen diffuses faster than oxygen in hydrogen-air and methane-air flames, while oxygen diffuses faster than nitrogen in flames of propane and other heavier hydrocarbons. In mixtures of air with propane or heavier hydrocarbons, the transition between stable and unstable regimes is predicted in mixtures that are leaner than the mixture corresponding to the peak of the burning velocity curve, in agreement with experimental observations. __________ Translated from Fizika Goreniya i Vzryva, Vol. 41, No. 5, pp. 14–22, September–October, 2005.     

Analysis of products of high-temperature pyrolysis of various hydrocarbons

Ethane, ethylene, acetylene, propane and neopentane have been pyrolyzed at 1173 K, and methane at 1372 K in a flow system, and the volatile pyrolysis products analyzed. Eleven aromatic hydrocarbons, containing 14 or fewer carbon atoms, accounted for 98 + % of the liquid products recovered in each case. Benzene was the main product, followed by naphthalene. No compounds with branched chains or multiple substituents were present, and compounds containing even numbers of carbons comprised 93–99% of each mixture. Acetylene was a major component of the gaseous effluent from each of the initial hydrocarbons. The effect of temperature on the composition of the gaseous effluent during pyrolysis of methane, ethane and ethylene was determined. Carbon film deposition from methane commenced at about 1273 K; from ethane at 1015 K and from ethylene at 1100 K, in each instance coinciding with the appearance of acetylene in the effluent. As the temperature was raised, at first the increase in the rate of carbon deposition closely followed the increase in the concentration of acetylene in the effluent. It is proposed that acetylene may be a common factor in the pyrolysis of aliphatic hydrocarbons, perhaps acting as the precursor of both surface carbon and aromatic hydrocarbons by a process of head-to-tail linkage of two-carbon units at active surface sites to form chains that then undergo dehydrogenation to carbon or cyclization and desorption as aromatic species.     

Effect of shear rate on the rate of polymerization of styrene

Application of shear was found to have considerable effect on the radical polymerization of styrene initiated by benzoyl peroxide. The initial rate of polymerization decreases by as much as 30% for low shear rates (γ), but on further increasing γ it increases slightly, levelling ultimately at the 10% reduction level. The effect of solvent was shown to have negligible effect, in direct contrast to that observed by Kumar et al.^1–3 for methyl methacrylate and acrylonitrile. Experiments confirm that the reduction in the rate of initial polymerization can be attributed largely to the change in initiator efficiency on the application of shear rate. As a further test, the decomposition rate of benzoyl peroxide in nitrobenzene at 80°C was measured and was found to increase significantly on application of shear. This confirms the importance of mass transfer resistance in removal of CO₂. The reduction in the rate of polymerization of styrene can now be explained as follows. In the reaction mass, there are benzoyloxy as well as phenyl radicals and styrene molecules have been shown by Bevington⁴ to react preferentially with the former. The fall in the rate of polymerization of styrene occurs because, on the application of shear, decomposition of benzoyloxy radicals is favoured in the forward direction and its concentration in the reaction mass falls. As a result the initiation of polymer radicals reduces, which in turn gives a lower rate of polymerization.     

催化还原脱除SO2研究的进展

烟气中的ＳＯ２的催化还原脱除过程受到还原剂和催化剂的双重影响,目前对这二者的研究相当广泛,尤其是对催化剂的研究取得了较大的进展。在研究过程中,人们探讨了其可能的机理,并对水蒸气等因素的影响作了研究。但大部分研究仅限于无氧尾气中ＳＯ２的脱除。本文将就这一过程研究的进展加以评述。     

Optimization of the process of drying of corn seeds with the use of microwaves

Abstract

The heating and drying of various types of food using microwave improve the economy of time and energy. The physiological quality variation of the seeds submitted to microwave drying is known to some extent. In this context, some authors have reported excellent performance using this technique, on germination rates, after drying. The commercial use of microwave drying in seeds is irrelevant, which motivates more extensive research on the benefits and challenges of this technique that can increase its insertion in the post-harvest handling steps of agricultural products. Corn is a product of high worldwide relevance. Therefore, the use of microwaves in its drying process has excellent potential to arrive at significant savings in its production. Thus, this study is aimed to evaluate the effects on the physiological quality of the seeds submitted to different drying conditions, using the microwave radiation. To that end, corn seeds, with a water content of 20% on wet basis (w.b.), were dried at 40, 50, and 60?°C, at power ratings of 0, 0.6, and 1.2?W/g; in the vacuum condition. Drying occurred continuously, with intermittent power, until the seeds reached the 12% wet basis; in this condition, the seeds could be stored with secure. Germination tests performed shortly after drying showed that the temperature of 40?°C at a power of 0.6?W/g had a reduction in drying time of approximately 5?h when compared to conventional drying (40?°C and 0.0?W/g). The evaluation of the physiological quality of the seeds showed no significant difference in the germination, vigor, and longevity indices of the treated seeds.     

3种肠杆菌科细菌的耐药性变迁

目的研究大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌的耐药性变迁。方法对2007～2009年临床分离的大肠埃希菌(645株)、肺炎克雷伯菌(260株)和阴沟肠杆菌(150株),采用纸片扩散法进行体外药敏测定,并依据美国临床实验室标准化协会(Clinical and Laboratory Standards Institute,CLSI)规定的标准,分析3种肠杆菌科细菌的耐药性变迁。结果大肠埃希菌、肺炎克雷伯菌、阴沟肠杆菌对氨苄西林的耐药率均较高;对头孢他啶的耐药率低于头孢噻肟;与2007年比较,2008年和2009年对头孢吡肟的耐药率明显增长;未发现对亚胺培南耐药菌株的产生。结论细菌耐药性不断增强已成为临床治疗面临的重要难题,应从耐药监测、医院感染控制、合理使用抗生素等多方面努力,减少细菌耐药性的产生。     

浅谈中国石化国际工程总承包的发展

中国石化所属工程公司,多年来积极开拓海外市场,取得了一定的成绩,但从市场占有区域、投标中标率、项目利润等几方面情况看,仍然不能令人满意。笔者重点对工程公司开展海外工程的现状和存在问题进行了较为详细的分析,对如何进行海外项目的筛选、投标报价、合同谈判、傈函管理、索赔等问题进行了详尽的阐述,对我国石化行业工程公司今后的发展方向提出了希望和建设性意见。     

Synthesis of fine powders of KTP-group compounds of stoichiometric composition

Precipitation of crystalline monophase nanopowders (50-100 nm in diameter) of stoichiometric binary orthophosphates of titanyl and alkaline metal in aqueous solutions has been studied. It has been shown that, in the formation of those powders, titanyl hydrophosphate can be used as a precursor. Rising temperature and alkaline ion concentration in the solution decrease the size of the powder grains, while elongating the exposure of the synthesized solid phase in the suspension increases grain sizes. An effective technique to synthesize fine-dispersed powders of monophase stoichiometric binary orthophosphates of titanyl and alkaline metal has been developed.     

气化给煤系统故障分析

气化给煤装置自投运以来,出现了气化煤仓堵煤、称重给煤机输送皮带因跑偏而损伤以及清扫装置故障频繁等问题,多次造成气化系统减负荷运行。通过对出现的各种问题进行分析,找到了产生这些问题的原因,并有针对性地采用配煤和改进清扫链等措施,使出现的问题得到了极大的改善。