基因工程在油菜遗传改良中的应用

从遗传转化的方法、所采用的外源基因以及转基因油菜的安全性三方面综述了基因工程在油菜遗传改良中的研究进展,并对本研究领域的发展趋势进行了讨论．     

农村电网改造中若干技术经济问题的研究

我国投入几千亿元进行城市电网和农村电网的改造，这是一项跨世纪工程。将这大量的资金如何科学而合理地运用到电网的改造和建设中，是当今政府及电力企业十分关注的热点问题。针对农村电网改造以节电效益最大为目标，着重分析了导线的经济截面选择，0.4 kV供电半径及配电变压器的布点方式等几个主要问题，并同时针对农村电网改造和建设提出了一些看法与大家共同商榷。     

有机修饰塿土对苯胺的吸附

以十六烷基三甲基溴化铵(CTMAB)单一修饰和CTMAB+十二烷基磺酸钠(SDS)混合修饰塿土耕层和粘化层土样,从吸附实验和热力学角度研究修饰土样对苯胺的吸附特征和机理。结果表明,供试土样对苯胺吸附均呈现100CB>50CB>120CS>CK的高低顺序,耕层修饰后对苯胺的平衡吸附量增大了4.5￣8.57倍,粘化层土样增大了6.0￣18.33倍;温度为40℃时耕层未修饰土样对苯胺的吸附量高于粘化层未修饰土样,20℃时则低于粘化层原土土样,而修饰土样则均呈现粘化层修饰土样对苯胺的吸附高于塿土耕层修饰土样的结果;耕层土样随温度升高苯胺平衡吸附量升高,而粘化层土样则表现出降温有利于苯胺吸附的现象,修饰剂对土样的修饰对苯胺的吸附具有"感温钝化"效应;Henry模型适用于描述苯胺的吸附;修饰土样对苯胺的吸附自由能变均为ΔG<0,属于自发反应,粘化层各土样对苯胺吸附为放热熵减过程,吸附自发性由焓减控制,耕层各土样对苯胺吸附为吸热熵增过程,其吸附自发过程为熵增控制过程;疏水吸附是修饰土样对苯胺吸附的主要机理,但修饰剂对于土壤表面的修饰是不均匀修饰,粘化层土样以物理吸附机制为主,耕层土样则存在化学吸附的机制。     

南瓜籽多糖乙醇分级沉淀与超声波改性研究

采用热水浸提、Saveg脱蛋白制备南瓜籽多糖,蒸馏水复溶后采用0~30%、30%~60%、60%~80%乙醇分级沉淀法得到3种多糖PSP-30、PSP-60和PSP-80。通过测定多糖、蛋白含量、单糖组成及利用红外和紫外光谱检测表明:PSP-30、PSP-60和PSP-80均为结合一定量蛋白的多糖,不含糖醛酸;PSP-30、PSP-60由鼠李糖、阿拉伯糖、木糖、甘露糖、葡萄糖和半乳糖6种单糖组成,PSP-80由鼠李糖、阿拉伯糖、木糖、葡萄糖、半乳糖5种单糖组成。3种多糖对DPPH自由基均有较高清除作用,其中PSP-60效果最好,当质量浓度2.5 mg/m L时,清除率为61.90%。多糖PSP-60经不同频率超声波处理后,单糖组成的物质的量比和抗氧化活性均有所改变,证实超声波可以造成多糖中单糖的转化和生物活性的改变。     

基于美拉德反应的酶改性大豆蛋白冻融稳定性研究

为提高大豆分离蛋白(SPI)的冻融稳定性,利用胰蛋白酶对SPI酶解处理得到不同水解度的大豆分离蛋白水解物(SPH),随后与葡聚糖发生美拉德反应生成大豆分离蛋白-葡聚糖共聚物(SPI-D)和大豆分离蛋白水解物-葡聚糖共聚物(SPH-D),研究基于美拉德反应的酶改性SPI的冻融稳定性。接枝度、褐变指数和内源荧光光谱的测定证明了SPI-D和SPH-D有美拉德反应的特定荧光物质生成,蛋白改性朝着有利于冻融稳定的方向进行。比较发现3次冻融循环后SPH-D乳液具有更好的冻融稳定性,尤其当水解度为3%时,SPH3-D乳液的粒径尺寸、聚结程度和出油率分别比SPI-D乳液降低了48.28%、81.61%和63.81%。激光共聚焦显微镜观察发现SPH3-D乳液在3次冻融循环后蛋白没有明显的桥联絮凝现象,油滴依然被紧密地包裹在界面膜中,表现出较好的冻融稳定性。     

Effects of Crystal Modification on the Binding of Trace Metals and Arsenate by Goethite (7 pp)

-  Dedicated to Prof. Dr. Ulrich Förstner on his 65th birthdayGoal, Scope and Background   Goethite (&#945;-FeOOH) as the most frequently occurring iron oxide in the environment plays a significant role in the binding of inorganic pollutants. Accordingly, synthetic goethite is used for the purification of contaminated water. Goethite crystals can be prepared in different shape as porous and non-porous forms. The mineral can also be modified by partial substitution of structural Fe+3 for different foreign elements. The biggest possible substituent known so far is Cd+2 which causes a strong expansion of the unit-cell parameters. An incorporation of Pb+4 generates a permanent positive charge. Goethites with these morphological and structural modifications were selected for sorption experiments with Co2+, Ni2+, Zn2+, Cd2+, Pb2+, and arsenate. It was intended to demonstrate the potential of mineral modification for improving sorption properties.Methods   Batch sorption studies were carried out combining each mineral with a single element at different pH and reaction times. Cations were investigated at a single initial concentration only while arsenate was tested over a range of concentrations in order to establish sorption isotherms. The sorption step was followed by an extraction step to characterize time dependent immobilization reactions.Results and Discussion   A time dependent increase of trace metal and arsenate sorption is attributed to a migration of ions into pores of star-shaped goethite and to a binding by specific sorption sites at the surface. The migration into pores is related to the size of adsorbing cations. The almost identical sorption behaviour of Ni2+ and Co2+ on pure goethite is contrasted by a strong preference of Co over Ni on Cd-goethite. Expansion of the unit-cell dimensions in Cd+2 substituted goethite generates highly specific binding sites at the surface. These are accessible to Co and Zn only. A permanent positive charge in Pb+4 substituted goethite reduces the binding of cations and doubles the sorption capacity for arsenate. Pb-goethite also contains a limited portion of highly specific sites which can only be accessed by Zn2+. Immobilization takes place even after a short contact time of 16 hours. This process results in a growing fraction of non-extractable metals and arsenate with reaction time.Conclusions   Pores and foreign elements in the goethite structure greatly affect the reactivity of the mineral and the ability to immobilize inorganic pollutants. A possible mechanisms for the preferred sorption of Co and Zn by Cd-goethite is seen in the ability of these metal ions to adopt a smaller size: Co by oxidation of Co2+ to Co3+ and Zn by tetrahedral coordination of Zn2+. This kind of binding can be viewed as structural incorporation. The binding properties of modified goethites can well be characterized by sorption tests including an array of elements with different ionic size and charge.Recommendation and Outlook   There is considerable potential for designing goethite modifications with improved surface reactivity for specific purposes such as water purification and possibly catalysis of reactions.     

托架工艺改进及水平摆动切口冲模设计

通过对此盘类件进行的结构与性能分析,以及严格的工艺计算,合理地利用单点压力机气顶的双重作用,减少了模具投入,降低了制造成本,提高了工作效率和零部件质量,产生了良好的经济效益。     

激光冲击波技术在金属表面改性和成形中的应用

在对激光冲击强化技术的原理、特点及工程应用须解决的关键问题进行系统分析的基础上,介绍了激光冲击波技术在金属板材成形方面的最新研究进展：激光冲击成形和激光喷丸成形,对激光冲击成形和激光喷丸成形的机理、技术特点及国内外的研究现状进行了综述,并对今后的应用前景和发展趋势作了分析.     

改性处理在提高木材耐腐性方面的研究概况

随着人类环境意识的提高,某些对环境和人体健康有较大影响的木材防腐剂(如铬化砷酸铜CCA)的使用受到限制或禁止。除了开发新的环保型木材防腐剂外,木材改性处理作为木材保护的另一手段,它在提高木材耐腐性方面的研究日益受到关注。本文主要介绍了木材改性处理的方法及防腐机理,并综述了国内外关于木材化学改性处理(以及热处理)后木材的耐腐性(以及抗虫蚁性)方面的研究现状,指出了我国在利用改性方法提高木材耐腐性方面研究所存在的问题,展望了今后研究和发展的方向。     

Removing constraints to sustainable food production: new ways to exploit secondary metabolism from companion planting and GM

The entire process of agricultural and horticultural food production is unsustainable as practiced by current highly intensive industrial systems. Energy consumption is particularly intensive for cultivation, and for fertilizer production and its incorporation into soil. Provision of nitrogen contributes a major source of the greenhouse gas, N₂O. All losses due to pests, diseases and weeds are of food for which the carbon footprint has already been committed and so crop protection becomes an even greater concern. The rapidly increasing global need for food and the aggravation of associated problems by the effects of climate change create a need for new and sustainable crop protection. The overall requirement for sustainability is to remove seasonal inputs, and consequently all crop protection will need to be delivered via the seed or other planting material. Although genetic modification (GM) has transformed the prospects of sustainable crop protection, considerably more development is essential for the realisation of the full potential of GM and thereby consumer acceptability. Secondary plant metabolism offers wider and perhaps more robust new crop protection via GM and can be accomplished without associated yield loss because of the low level of photosynthate diverted for plant defence by secondary metabolism. Toxic mechanisms can continue to be targeted but exploiting non‐toxic regulatory and signalling mechanisms should be the ultimate objective. There are many problems facing these proposals, both technical and social, and these are discussed but it is certainly not possible to stay where we are in terms of sustainability. The evidence for success is mounting and the technical opportunities from secondary plant metabolism are discussed here. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.