含氟杀鼠剂

1鼠害的严重性我国野生鼠类有180多种，以植物的根、茎、叶、花、果实和种子为食。非人工饲养的野鼠，对人类的危害是多方面的。对农田有明显危害的野生鼠有60多种［1］，它们严重损耗和糟蹋农作物，极大地破坏农业生产。1993年我国发生鼠害的农田有21，500万公顷［2］，占耕地面积1／4，损失粮食1，500万吨。浙江省每年损失粮食35万吨［3］。四川省石渠县鼠害失控，鼠害以每年22．4％递增［4］。1983年仅湖北省因鼠害造成颗粒无收的农田达30万亩，损失皮棉30万担，咬伤咬死猪、耕牛5，000余头及鸡鸭4000余万只［1］。据统计，全世界每年粮…     

2—氯—4—二甲胺基—6—甲基嘧啶的合成

合成了杀鼠剂２－氯－４－二甲胺基－６－甲基嘧啶,用正交试验法研究了物料配比及反应对产品收率的影响。对中间体的化学结构、产品的熔点及含量进行了测定,并试验了产品对褐家鼠、大白鼠及家兔的毒力。     

杀鼠新玉米毒饵的有效成分分析

本文研究了以ＦｅＣｌ３为显色剂，用可见分光光度法测定了杀菌新玉米毒饵中杀鼠新的含量，选定丙酮为毒饵的萃取溶剂，萃取时间３．５小时，５分钟显以时间，最大吸收波长４９２纳米。杀菌新在０．０２－０．２０毫克／毫升范围内呈良好的线性关系，检出下限为０．００５７毫克／毫升；考查了不同毒饵添加剂对本分析方法的干扰。实验证明，本方法经济简便，准确性及重现性均良好；利于普及和应用。     

国内外杀鼠剂研制的回顾与展望

回顾了数年来国内外急慢性杀鼠剂研制情况，展望了今后杀鼠剂研制的方向和需要解决的问题。     

双对氯三氟甲苯敌鼠的合成

本文介绍了以三氟异丙醇，对氯三氟甲苯，邻苯二甲酚二甲酯为原料合成双对氯三氟甲苯敌鼠的方法。     

三种缓效性杀鼠剂防治中华鼢鼠试验

中华鼢鼠在我国西北、华北地区猖獗发生,危害成灾,是生产上亟待解决的问题。筛选安全、高效的杀鼠剂是当务之急。缓效性杀鼠剂具有不产生抗药性、无二次中毒、不杀伤天敌(狐狸、狗、猫等)等优点,它的成功应用,将多方面弥补速效性杀鼠剂的不足,提高中华鼢鼠的化学防治水平。为此,笔者就缓效性杀鼠剂进行了试验,结果总结如下。     

国内外防鼠药剂的发展

论述了杀鼠剂国内外发展趋势，并列举了其中应开发的品种。     

溴鼠胺的合成

本文对鼠类的危害和化学杀鼠剂作了简要叙述，对2－氯－3，5－二硝基三氟甲苯经氟化、胺化、溴化合成溴鼠胺的方法进行了研究。     

生物基1,6-己二醇的研究进展

传统的以石油化工产品为原料的石化基1,6-己二醇(1,6-HDO)的生产存在能耗高、反应产物分离困难、污染环境等缺点,以5-羟甲基糠醛(5-HMF)为原料制备生物基1,6-HDO可以克服这些缺点。本文介绍了国内外制备生物基1,6-HDO的研究进展,总结并讨论了由5-HMF制备1,6-HDO的不同反应路径,并从反应物吸附、金属粒径、活性组分协同作用、载体等角度对比了不同催化剂体系及其催化机理,探讨了各种催化剂促进C=O加氢、呋喃环C=C加氢、呋喃环C—O氢解开环反应,抑制呋喃环、呋喃环侧链C—C氢解断裂反应的性能。与多步法相比,一步法制备1,6-HDO的反应步骤简单,但1,6-HDO的产率相对较低,因此开发高效的催化剂体系和反应工艺将是今后研究的重点。     

Emerging role of nanobiocatalysts in hydrolysis of lignocellulosic biomass leading to sustainable bioethanol production

Catalytic conversion (hydrolysis) of carbohydrate polymers present in the lignocellulosic biomass into fermentable sugars is a key step in the production of bioethanol. Although, acid and enzymatic catalysts are conventionally used for the catalysis of various lignocellulosic biomass, recently application of immobilized enzymes (biocatalysts) have been considered as the most promising approach. Immobilization of different biocatalysts such as cellulase, β-glucosidase, cellobiose, xylanase, laccase, etc. on support materials including nanomaterials to form nanobiocatalyst increases catalytic efficacy and stability of enzymes. Moreover, immobilization of biocatalysts on magnetic nanoparticles (magnetic nanobiocatalysts) facilitates easy recovery and reuse of biocatalysts. Therefore, utilization of nanobiocatalysts for catalysis of lignocellulosic biomass is helpful for the development of cost-effective and ecofriendly approach. In this review, we have discussed various conventional methods of hydrolysis and their limitations. Special emphasis has been made on nanobiocatalysts used for hydrolysis of lignocellulosic biomass. Moreover, the other most important aspects, like nanofiltration of biomass, conversion of lignocellulose to nanocellulose, and toxicological issues associated with application of nanomaterials are also discussed.     

Aggregation pheromone system of adult gregarious desert locust schistocerca gregaria (forskal)

Six electrophysiologically active aromatic compounds, viz., anisole, benzaldehyde, veratrole, guaiacol, phenylacetonitrile, and phenol, were identified in the volatiles of older-adult male desert locust. Young adults and females of all age groups produced none or only trace quantities of these compounds. Comparison of the aggregation responses of young and older adults to the crude, older-adult, volatile extract and different synthetic blends of the six compounds showed that the aggregation pheromone system of the adult gregarious locust consists of phenylacetonitrile, guaiacol, phenol, and benzaldehyde. Like the crude volatile extract of older males, neither the synthetic blend of the six compounds nor the adult pheromone blend evoked any significant aggregation responses from nymphs. These results confirm our previous report of sexual differentiation in the production of adult aggregation pheromone in the desert locust and of the evidence of two distinct aggregation pheromone systems in the two stages of the insect.     

Soil nutrient depletion by agricultural production in Southern Mali

The degree of soil mining by agricultural production in Southern Mali is assessed by calculating nutrient balances: differences between the amount of plant nutrients exported from the cultivated fields, and those added to the fields. Export processes include extraction by crops, losses due to leaching, to erosion, and to volatilization and denitrification. Inputs include applications of fertilizer and manure, restitution of crop residues, nitrogen fixation, atmospheric deposition of nutrients in rain and dust, and enrichment by weathering of soil minerals. Nutrient balances are calculated for N, P, K, Ca, and Mg. Both pessimistic and optimistic estimates are given.The resulting figures indicate, even when the most optimistic estimates are used, large deficits for nitrogen, potassium and magnesium. For the region as a whole, the calculated deficits are -25 kg N/ha,-20 kg K/ha, and -5 kg Mg/ha. Further, acidification is to be expected, in particular in areas where cotton is grown. The deficits are caused by traditional cereal crops, but also by cotton and especially by groundnut. The latter two crops are fertilized, but insufficiently. It is important to note, that the negative figures are not automatic recommendations for application of a specific amount of additional fertilizer. For phosphorus and calcium the balance of the region as a whole appears to be about in equilibrium, but locally large variations may occur.Erosion and denitrification are important causes of nutrient loss, accounting respectively for 17 and 22% of total nitrogen exports. Atmospheric deposition and weathering of minerals in the soil are still important nutrient inputs that contribute as much as nutrients as organic and mineral fertilizer combined. Nutrient depletion is very large in comparison to the amount of fertilizer applied. Drastic options, such as doubling the application of fertilizer or manure, or halving erosion losses, even if feasible, would still not be enough to make up for the calculated deficits.The annual value of withdrawn nutrients, if related to prices of fertilizers, varies between 10,000 and 15,000 FCFA/ha (40-60 US $/ha). Since the estimated average gross margin from farming in this area is 34,000 FCFA/ha (123 US $/ha), soil mining appears to provide an amount equal to 40% of farmers' total income from agricultural activities.     

Observation and measurement of the appearance of metallic materials. Part II. Micro appearance

Part I of this article dealt with the appearance of metallic materials observed at a distance of a few meters. This part deals with the appearance at reading distance. Metallic materials exhibit various appearance attributes, including glitter, glints, depth, coherence glitter, binocular luster, binocular glitter, and binocular mottle. Color disparity is proposed as a measure of binocular luster. Metallic materials resemble grainy photographs, so the method used in photography to quantify graininess by measuring blending distance is introduced. Objective measures of granularity are proposed as correlates of graininess. The term “subsurface” is applied to the apparent “surface” lying beneath the glossy surface. Methods of optical image analysis, such as point spread function, edge spread function, Wiener spectrum, modulation transfer function, and image correlation are proposed to characterize the appearance of metallic surfaces. Polarization and cylindrical presentation may aid measurements. Binocular attributes of appearance introduced here require analysis of the disparity between two points of view. New kinds of pigments may require new methods of measurement. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23: 362–373, 1998     

丙烷氧化脱氢制丙烯研究进展

开发新型丙烯制备工艺对于满足人们日益增长的丙烯需求具有重要意义。由于商业化无氧脱氢技术存在热力学平衡限制、反应温度高、催化剂易积炭等不足,近年来,人们将研究重心转向了丙烷氧化脱氢技术。本文简述了丙烷氧化脱氢制丙烯的发展现状,综述了近年来文献报道的丙烷氧化脱氢催化剂体系（V基、Cr基、Co基、Ni基、Mo基、Pt基、Ce基和非金属基催化剂）、机理研究和不同氧化剂选择,并对各自的优势和不足进行了简单分析。分析发现,虽然目前丙烷氧化脱氢催化剂的种类非常广泛,但产物丙烯的收率仍有待提高,机理研究也需要更加系统和深入。最后指出,系统研究丙烷氧化脱氢机理,并在此基础上开发先进催化剂,进一步提高丙烯的选择性和收率是未来丙烷氧化脱氢研究的重要方向。     

从废旧高温合金的硫酸浸出渣中浸出分离钨钼铼

对废旧高温合金硫酸浸出残渣选择HCl-FeCl3-H2O2体系氧化浸出、浸出后加入NaOH调节溶液pH值,使钨、钼、铼与铌、钽等分离,研究了反应时间、反应温度、HCl用量、FeCl3用量、H2O2用量对钨、钼、铼浸出率的影响. 结果表明,该体系能充分浸出渣中钨、钼、铼3种金属,添加FeCl3可提高钼在盐酸溶液中的浸出率. 在浸出温度70℃、浸出时间5 h、FeCl3用量100 g/L、H2O2用量10 mL/g及HCl初始用量10 mL/g的条件下,钨、钼、铼浸出率分别大于97%, 86%, 91%.     

镍基催化剂的研究进展

镍基催化剂是一种由多孔结构的镍铝合金的细小晶粒组成的固态异相催化剂。镍基催化剂因具有机械强度高、催化活性好、制备简单、价格低廉等优点,被广泛地应用到石油、化工、制药、油脂、香料、双氧水、合成纤维等方面的加氢、脱氢、脱卤、脱硫等转化反应过程中。随着催化工业的逐步发展,对催化剂性能的要求也越来越高,原始的镍基催化剂利用率低、抗酸性差等缺点限制了该催化材料的进一步应用。因此,近年来,许多研究者一直在尝试对镍基催化剂进行改性,以改善其使用寿命、催化活性、抗酸性等性能。着重介绍了镍基催化剂的强化措施以及镍基催化剂的应用,并对镍基催化剂在各类催化反应中的应用情况进行了详细概述,在此基础上展望了镍基催化剂的未来发展。     

氨基纤维素合成与应用的研究进展

氨基纤维素是末端带有氨基的纤维素衍生物,化学结构与壳聚糖相似。氨基基团的引入使纤维素大分子具有很好的溶解性、成膜性和吸附重金属离子特性,并在酶的固定、药物缓释等生物领域有很好的应用前景。氨基纤维素的合成过程相对复杂,主要体现在中间产物的制备以及氨基纤维素的合成2个阶段,其合成过程的选择性和经济性较差,导致氨基纤维素的生产和应用受限。笔者主要对氨基纤维素的合成途径进行了综述,并对氨基纤维素的膜保护、固定酶和吸附等应用进行了总结。     

活化过硫酸盐氧化法降解酚类污染物的研究进展

活化过硫酸盐氧化法因具有经济、高效、环保、安全稳定等优势,近年来在酚类污染物的降解中备受关注。目前活化过硫酸盐降解酚类污染物的方法主要包含外加能量活化和外加催化剂活化两大类。其中单一的热活化、光活化、超声活化、电化学活化、等离子体活化等外加能量活化过程能量消耗较大,且对酚类污染物不易达到满意的降解效果。过渡金属活化和碳质材料活化等外加催化剂活化方式,由于环境污染小、操作成本低、降解率高等优点,越来越受到科研工作者的重视。为了提高对酚类污染物的降解率,不同的过硫酸盐活化方式不断融合,逐渐形成多种耦合活化方式,例如,碳质材料与过渡金属的耦合活化、电化学与过渡金属催化剂的耦合活化以及光与外加催化剂的耦合活化等。本文论述了活化过硫酸盐氧化法降解酚类污染物的研究进展,概述了活化过硫酸盐的影响因素,分析了活化过硫酸盐降解酚类污染物存在的问题,展望了活化过硫酸盐降解酚类污染物的发展方向。