柞蚕肠液理化性质与饲料效率的相关性研究

对柞蚕肠液的理化性质与饲料效率的相关性进行研究的结果表明 :柞蚕肠液对促进蚕体抗病与消化吸收功能有着重要作用 ,平均每头蚕有肠液 1 76mL ,品种间开差为 0 78mL ,相对开差 5 7 80 % ,肠液量越多 ,饲料效率越高 ;柞蚕不同品种肠液pH平均值未发现明显差异 ,但强健好养饲料效率高的品种个体间开差小 ;柞蚕肠液缓冲力除与品种强健性有关外 ,还与品种的饲料效率呈正相关 ,在强健丰产与高饲料效率品种中 ,肠液恢复pH原值所需时间越短 ,饲料效率越高 ,电刺法取出肠液后 ,肠液恢复缓冲力所需时间是恢复其pH原值时间的 1 8倍多 ,同恢复肠液pH原值所需时间长短与品种强健性和饲料效率的关系完全一致。     

提高中锰白口铸铁韧性的研究

为改善中锰白口铸铁的韧性以扩大其应用范围,本文探讨了C, Si, Mn等合金元素、变质处理和热处理工艺对中Mn白口铸铁组织和性能的影响.     

Influence of the physical and chemical properties of soil on the retention process of isoxaflutole and its two main derivatives

Isoxaflutole is a new pre‐emergence herbicide for use in maize and sugarcane. Its two main derivatives are a diketonitrile derivative, the 2‐cyano‐3‐cyclopropyl‐1‐(2‐methanesulfonyl‐4‐trifluoromethylphenyl)propan‐1,3‐dione, named DKN, and a benzoic acid derivative, the 2‐methanesulfonyl‐4‐trifluoromethylbenzoic acid, named BA. The adsorption/desorption processes have never been studied for isoxaflutole (IFT) at high concentrations nor for BA, and the present work aimed at completing the knowledge of the behaviour of these three molecules in conditions close to those encountered in the context of agricultural use. The adsorption/desorption study was conducted on seven soils of different physical and chemical properties, using the batch equilibrium technique. During the experiments, IFT was chemically converted into DKN in a continuous manner. This reaction appeared to be dependent on the pH of the soil and was taken into account in the calculations of the adsorbed and desorbed amounts. The adsorption isotherms obtained were predominantly C‐shaped for IFT and DKN and S‐shaped for BA, but some differences appeared on a few soils. They fitted well the Freundlich equation, and the values of the Freundlich coefficient K_fa showed that, whatever the soil, IFT was more adsorbed than its two derivatives. The main parameter influencing the adsorption of IFT appeared to be the organic matter content, whereas this effect was not evident for DKN and BA. No correlation was found between the extent of adsorption and either clay content or pH of the soil, for the three molecules.     

十种常用农药与球孢白僵菌的生物学相容性

球孢白僵菌孢子粉与10种常用农药相容性的测定结果显示,随着孢子浓度上升,所试农药对孢子的抑制作用均有不同程度的增强。在1/10田间常规使用浓度下,百菌清和代森锰锌均能抑制或杀死孢子(萌发率<1％)。除阿维菌素外,所有杀虫剂均与白僵菌孢子相容,在常规使用浓度的10倍稀释液中孢子萌发率达90％以上。吡虫啉、蚜虱灵、灭多威和氟虫腈与孢子的相容性最好,其中吡虫啉和蚜虱灵对孢子萌发率的影响不明显随药剂浓度的变化而变化,即使在田间常规使用浓度下孢子萌发率也在95％以上,而阿维菌素与白僵菌的相容性极差。因此,应用白僵菌制剂防治害虫,选择生物学相容性好的农药以低剂量与白僵菌制剂混用,既可使菌剂增效,又可大幅度降低化学药剂用量。     

长期不同施氮量下黑土团聚体稳定性及有机碳含量的变化

为测定不同氮肥施用量对黑土团聚体组成及稳定性、有机碳含量及团聚体有机碳分布的影响,阐明黑土有机碳稳定性对不同施氮水平的响应机制,本研究在吉林省梨树县不同施氮水平长期定位试验田进行取样,以施氮水平不同设置5个处理,分别为T1(0)、T2(160 kg·hm^-2)、T3(240 kg·hm^-2)、T4(280 kg·hm^-2)、T5(320 kg·hm^-2),分析长期不同施氮量下水稳性团聚体组成、团聚体结构特征、土壤总有机碳含量及团聚体有机碳分布的变化,探究酸化黑土有机碳含量影响特征。结果表明：随氮肥施用水平的升高,土壤碱解氮(AN)和全氮(TN)含量先增后减,T3处理含量最高,AN和TN分别比T1处理高24.90%、10.28%;土壤速效磷(AP)的含量呈下降趋势。随氮肥用量的提高,土壤团聚体呈现大粒径团聚体向小粒径团聚体转变的趋势,>2 mm粒径团聚体下降14.55%。土壤有机碳总量随施氮水平的提高呈先增后减的趋势,施氮量为280 kg·hm^-2有机碳含量最高;>2...     

湖南湘潭矿业废弃地土壤特性研究

对湖南湘潭锰矿废弃地的土壤基质特殊性和少量自然定居植物营养元素和重金属元素含量进行研究.结果表明:尾矿废弃地土壤以砂粉土为主,通气透水性能差,渗透系数小,易造成地面积水;矿渣废弃地渗透系数大,蓄水量少而蒸发失水强,抗旱力弱.2类废弃地土壤营养元素含量低,重金属元素锰、铜的含量高,毒害大.在自然定居的少量植物中,商陆和荩草为超积累植物.采用植物生物原位修复法改善极端生境条件,既经济又高效.     

铜在狐尾藻中的积累及亚细胞分布和化学形态

为探索狐尾藻对重金属铜的积累和耐性机制,本研究通过水培试验,研究不同浓度铜处理（0、20、50 mg·L^-1）对狐尾藻（Myriophyllum spicatum L.）生长生理特性以及叶片表皮细胞形态的影响,分析各器官中铜吸收转运及铜在各组织器官亚细胞中的分布和化学形态。结果表明：各浓度铜处理下狐尾藻均能存活,但铜浓度高于50 mg·L^-1时,狐尾藻根、茎、叶生物量相比对照（铜 0 mg·L^-1）处理降低53.48%、36.99%和32.22%。铜处理后,狐尾藻根、茎和叶铜含量分别为11.81~186.34、1.32~7.89、2.11~11.99 mg·kg^-1,根系中铜含量均高于叶片和茎部。铜在狐尾藻中的亚细胞分布主要位于根、茎、叶的细胞壁部分（36.49%~49.61%、45.44%~49.92%、41.45%~55.92%）,其次是可溶性组分（21.65%~25.99%、23.03%~27.65%、18.01%~34.63%）。狐尾藻中铜的赋存化学形态以盐酸提取态、醋酸提取态和乙醇提取态为主,所占比例为76.34%~86.67%,均是活性较低的形态。因此,狐尾藻是铜富集较好的植物,其根部的耐性大于茎、叶。铜以吸附态或蛋白质、果胶酸盐等低活性形态赋存于细胞壁或可溶性组分（液泡）中是狐尾藻积累和耐受铜的重要机制。     

Approaches to Configuration Determinations of Flexible Marine Natural Products: Advances and Prospects

Flexible marine natural products (MNPs), such as eribulin and bryostatin, play an important role in the development of modern marine drugs. However, due to the multiple chiral centers and geometrical uncertainty of flexible systems, configuration determinations of flexible MNPs face great challenges, which, in turn, have led to obstacles in druggability research. To resolve this issue, the comprehensive use of multiple methods is necessary. Additionally, configuration assignment methods, such as X-ray single-crystal diffraction (crystalline derivatives, crystallization chaperones, and crystalline sponges), NMR-based methods (JBCA and Mosher’s method), circular dichroism-based methods (ECCD and ICD), quantum computational chemistry-based methods (NMR calculations, ECD calculations, and VCD calculations), and chemical transformation-based methods should be summarized. This paper reviews the basic principles, characteristics, and applicability of the methods mentioned above as well as application examples to broaden the research and applications of these methods and to provide a reference for the configuration determinations of flexible MNPs.     

宁波苦丁有效成分提取方法的比较及其抗氧化活性的研究

采用水蒸气蒸馏法(SDE)、乙醇法(EE)、超声波法(UWE)、微波法(MAE)和超临界CO2萃取法(SCDE)提取宁波苦丁有效成分,得率分别为:0.048%、0.011%、0.631%、0.522%和0.935%,毛细管GC-MS法分别鉴定出10、9、12、9和20种成分,体外抗氧化活性测试均显示了抗氧化结果,活性强度依次为:超临界CO2萃取法＞超声波法＞水蒸气蒸馏法＞乙醇法＞微波法.     

48%盖灌能EC冬春两季防除加拿大一枝黄花试验

[目的]探索高效、节能的加拿大一枝黄花防除办法。[方法]设不同浓度的盖灌能EC、龙拳SG、农达AS、莎阔丹SL、使它隆EC与对照（CK）9个处理来验证防除效果。[结果]冬除药后7 d,除对照外各小区普遍表现叶片发黄、心叶萎蔫,其中48%盖灌能高、低量与20%使它隆处理中毒症状最明显,其次为46%莎阔丹处理。48%盖灌能同75%龙拳复配处理和41%农达处理中毒略轻,中毒最轻的为75%龙拳的两个处理;药后15 d,各用药处理中毒症状进一步加重;春除比冬天见效快。[结论]重发地区宜在春秋两季出苗高峰后连续两次用药,春除时采用48%盖灌能EC 3 L/hm^2或48%盖灌能EC 2 000 ml/hm^2＋75%龙拳SG 150 g/hm^2处理,冬除时除可选用春除配方外,还可使用41%农达AS 4 500 ml/hm^2。连续两次防治后,效果较理想。