Nickel accumulation and its effects on the survival rate of Spodoptera litura Fabricius under continuous nickel stress

The artificial diets mixed with various concentrations of nickel were offered to the larvae of the phytophagous insect Spodoptera litura Fabricius for 3 generations. Nickel accumulations in the 6th instar larvae, pupae and newly emerged adults of the corresponding generations of S. litura were investigated by Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and the effects of nickel accumulations on the survival rate of S. litura were also evaluated by individual rearing. The results showed that nickel accumulated in the 6th instar larvae, pupae and adults of S. litura, and the accu- mulated nickel in all the tested developmental stages within a generation increased with the increase of the nickel doses in the treated diets and showed significant dose-dependent relationship with the nickel doses in the artificial diets. The results also indicated that the nickel accumulations in the 6th instar larvae, pupae, and newly emerged adults from the 3rd generation were higher than those from the 2nd generation, which were also higher than those from the 1st generation. Nickel concentrations in pupae and adults were significantly lower than those in larvae, which indicated that the excessive nickel might be excreted during metamorphosis. Furthermore, larval survival rate, pupation rate and eclosion rate of S. litura in the tested three generations all decreased with the increase of the nickel doses in the treated diets.     

重组抑肽酶的表达纯化和活性测定

抑肽酶是一种用途广泛的丝氨酸蛋白酶抑制剂.用基因重组技术将化学合成的抑肽酶基因插入表达载体pET28a,并转化至大肠杆菌Rosetta(DE3)中,经IPTG诱导后,表达产物以包涵体形式存在于菌体内包涵体纯化后经复性及CM-阳离子交换层析后,从每升培养液可获得2.4 mg抑肽酶,纯度可达90%.活性测定结果显示,重组抑肽酶可竞争性抑制纤溶酶对小分子底物S2251的水解活性.抑制常数(Ki)为(0.6±0.3)nmol/L,与天然抑肽酶的抑制活性相似.     

全位置TIG管焊机焊接电流的平滑曲线控制

采用单片机及逐次线性插值法设计出焊接工件圆周上相应位置的焊接规范参数曲线，实现了全位置ＴＩＧ管焊机焊接电流的平滑调节，精确控制电弧能量的分布，使焊缝熔透均匀，表面成型美观该焊机自动化程度高，操作方便，且具有罗强的稳定性。     

气隙式膜蒸馏法分离浓缩透明质酸水溶液的研究

介绍了应用气隙式膜蒸馏分离技术对透明质酸热敏性水溶液的浓缩分离情况. 结果表明, 使用膜孔径为0.2μm的聚四氟乙烯微孔疏水膜可使原料液的浓度提高1.6倍以上, 透明质酸截留率为80%以上. 探讨了循环时间、平均温差、热侧温度等条件对分离效果的影响, 并讨论了膜蒸馏过程热效率的变化规律.     

共沉淀法制备Zn-La-Al型混合金属氢氧化物纳米材料及其性能研究

采用非稳态共沉淀法制备了 Ｚｎ Ｌａ Ａｌ 型混合金属氢氧化物纳米颗粒材料，研究了沉淀过程的机理、产品的化学组成、粒度、晶态、等电点和红外光谱等，考察了沉淀剂（ Ｎ Ｈ４ Ｏ Ｈ、 Ｎａ Ｏ Ｈ 和 Ｋ Ｏ Ｈ） 对产品性能的影响     

MoSi2对二硼化钛惰性阴极材料性能的影响

用冷压烧结法制造了二硼化钛惰性阴极，研究了MoSi     

西部地区经济发展过程中环境犯罪构成研究

西部开发是促进我国经济发展的重要举措，西部开发必须与西部的生态环境的发展相适应，然而由于历史、文化、经济等方面的原因，西部地区的环境犯罪现象比较严重，面对这一状况，应完善刑法法律制度，打击环境犯罪，保障西部地区经济的良好发展。     

综述英语语音意识与英语阅读之间的关系研究及其对英语教学的启示

英语语音意识是影响英语阅读习得的元语言意识之一。在西方国家，语音意识与阅读关系的研究在心理语言学界占有重要研究领域。大量研究者得出结论，儿童早期发展起来的语音意识与他们后续阅读能力的发展高度相关。在英语教学中，提高学生的英语语音意识，对提升他们的英语阅读能力有重大意义。     

浅谈我国未来循环经济的发展与战略选择

循环经济是一种新兴的物尽其用的经济发展模式,它强调资源的再使用和再循环。实行循环经济是保障工业企业可持续发展的客观需要,也是实施可持续发展战略的重要途径和实现方式。 更多还原     

取代苯甲酸酸性比较

本文根据实验数据和电子效应理论，解释了取代苯甲酸三个同分异构体之间酸性强弱的原因。