工程堆积体坡面不同植被格局的控蚀效果研究

为探明不同植被格局对工程堆积体陡坡坡面土壤侵蚀的影响,采用10,20,30 L/min 3种放水流量,对黄土区不同格局（裸坡、坡顶、坡中、坡底、条带）下的高陡边坡（32°,20 m×1 m）进行模拟放水试验,选取径流率、产沙率、减流效益、减沙效益等因子对堆积体坡面植被的控蚀效果进行分析。结果表明：3种放水流量下,条带、坡顶、坡中、坡底的平均径流率较裸坡分别减小57.33%,61.17%,41.62%,24.78%,平均产沙率较裸坡分别减小74.99%,61.10%,55.01%,46.43%,且径流率与产沙率的线性关系（R²=0.57~0.80,p<0.01）整体上弱于裸坡（R²=0.71,p<0.01）。不同植被格局中,条带及坡顶格局的减流效益分别是65.97%,60.52%,减沙效益分别为71.44%,57.22%,二者的控蚀效果远高于其他格局。产沙率与径流功率的线性相关性（R²=0.61~0.83,p<0.01）高于径流剪切力（R²=0.29~0.76,p<0.01）,径流功率能更好地反映堆积体坡面土壤侵蚀机制。     

基于LQG理论的电子控制空气悬架控制策略研究

根据主动悬架控制理论,采用滤波白噪声作为路面随机输入激励,建立1/4车辆空气悬架模型。同时将电子控制空气悬架（Electronic Control Air Suspension,ECAS）等效为车身质量与车轮质量之间并联阻尼器、弹簧与悬架控制力的模型,将空气弹簧的作用力分解为定常刚度的弹簧力与可变悬架作用力。提出将线性二次型高斯控制理论（LQG）应用到电子控制空气悬架中。在线调整了控制目标的加权系数,使得车身加速度、悬架动行程和轮胎动位移达到比较理想的效果。     

T型板刀式秸秆还田机刀辊设计

采用T型板式刀具和支撑切削原理进行秸秆粉碎还田,以双螺旋线形式合理布置T型刀具并设计还田机刀辊。该还田机刀辊转速低,功耗小,粉碎秸秆,破除根茬,作业质量高。     

Investigation on redox status and gene expression related to larval cryopreservation in the Pacific oyster Crassostrea gigas

This study evaluated the effects of larval cryopreservation on redox status of post-thaw trochophore larvae and on gene expression in post-thaw trochophore larvae, D-larvae, umbo larvae, eyed larvae and spat, with the aim to understand the effects of cryodamage in the Pacific oyster Crassostrea gigas. The results showed that total antioxidant capacity was significantly higher in the cryopreserved larvae than in the control group (P?<?0.05), with no significant difference in the production of reactive oxygen species between these two groups (P?>?0.05). The expressions of FADD, Bax1, Baxlike, Bcl2, CASP7 and CAT were significantly downregulated in post-thaw trochophore larvae, whereas the expression of the SOD gene was significantly upregulated. However, the expressions of all of these genes did not significantly differ at later developmental stages. In the cryopreserved group, the expressions of GPX and ATG6 were downregulated in trochophore larvae and upregulated in D-larvae, while there were no signficant changes in the expressions of BI-1, Caspase 3 and ATG8 at all developmental stages investigated. Taken together, these results suggest that the larval cryopreservation technique developed for the Pacific oyster may compromise the survival of post-thaw trochophore larvae by modifying the redox status and gene expression patterns, but that they have limited effects, if any effect at all, after the umbo stage, indicating that the umbo stage should be used for assessing post-thaw larval performance in this species.

     

一种新的对虾病原菌——雷氏普罗威登斯菌

本文从患败血病的中国对虾体内分离到多株细菌，其中三株经人工感染证实为病原菌，又经４０多项形态、生理、生化特性测试，鉴定为雷氏普罗威登斯菌（Ｐｒｏｖｉｄｅｎｃｉａｒｅｔｇｅｒｉ），其主要特性为杆状，革兰氏阴性，周生鞭毛，运动，无自然游动现象，兼性厌氧，苯丙氨酸脱氨酶、柠檬酸盐利用、吲哚、甲基红反应均阳性，发酵甘露醇、肌醇、甘露糖产酸。赖氨酸、鸟氨酸脱羧酶、精氨酸双水解酶、ＶＰ反应均阴性。生长最适温度、ＮａＣｌ、ｐＨ范围分别为２５℃—３０℃、０５％—１５％、７０—９０。对羧苄青霉素、先锋霉素５号、氯霉素、ＳＭＺ＋ＴＭＰ、氟哌酸、链霉素等极为敏感。雷氏普罗威登斯菌引起对虾败血病在国内外尚属首次报道。     

稻瘟菌侵染诱导的水稻过氧羟基脂肪酸羟化环氧化酶的抗血清制备

 通过选择性抽提、盐析、阴阳离子交换柱层析等步骤从非亲和性稻瘟菌侵染的120g稻叶中获得了诱导性过氧羟基脂肪酸羟化环氧化酶(POG)的电泳纯蛋白250μg。利用这些纯化蛋白,制备了POG的抗血清。点免疫杂交结果表明,该抗血清效价大于1:5000,其抗原检测灵敏度可达0.05ng,并具有较好的特异性。蛋白印迹结果显示,稻瘟菌侵染可诱导POG在水稻细胞膜上的累积。     

变偏移距VSP资料处理方法研究

变偏移距VSP这门勘探技术自从提出来已经有20多年的历史了,但是,变偏移距VSP的应用还是止步不前,主要原因在于变偏移距VSP方法与常规VSP方法相比有波场复杂、波场分离困难的缺陷.然而,由于该方法检波器可以固定在储集层的上方,有利于描述储层性质及其纵横向变化情况,当有油气显示时,用变偏移距VSP探测漏掉的油气层是很有效的.在理论分析的基础上,编写程序实现了抛物拉冬变换的正、反变换,利用此程序成功实现了复杂条件下变偏移距VSP资料的上、下行波和转换波的分离,效果明显,并且具有实用性.     

14C-水杨酸在葡萄植株中的运输和分配

将14C标记的水杨酸(salicylic acid,SA)通过涂抹叶片背面引入葡萄幼苗.试验结果表明,水杨酸不易向外运输,具有以韧皮部运输为主、向下运输为主的特点.     

兔伪结核病诊断

伪结核病是由伪结核耶新氏菌引起的一种人畜共患传染病.本病以肠道、内脏器官和淋巴结等发生干酪样坏死结节为特征,与结核病类似,因而得名伪结核.     

红曲霉菌在畜牧业中的研究现状及应用前景展望

本文对红曲霉菌及其代谢产物进行了介绍,并对其在畜牧业中研究现状及应用前景进行了综述。