一种新型油茶果摘果机研制及动态特性试验研究

为改善现有油茶果摘果机工作效率低以及需要人工辅助采摘等技术难点，设计了一种基于多连杆机构的油茶果采摘机，通过液压系统驱动执行机构进行往复运动，实现了振动式自动采摘油茶果。本研究首先介绍了基于多连杆机构的油茶果摘果机工作原理，确定了曲柄滑块机构关键部件的结构参数并完成了可调速液压系统设计。然后，开展了油茶果摘果机关键部位加速度和动态应力测试，评估了运动特性及强度指标。结果表明，整机能够正常运转，但是，滑块最大加速度为90 m·s^-2，上底盘最大应力为541 MPa，安全系数<1，需要开展优化设计。     

Research Progress and Breeding Prospects of Grain Size Associated Genes in Rice

The breeding objectives of rice include high yield and good quality. Grain size is the three-dimensional structure of seeds, which is one of the key traits determining grain yield and quality in rice. To date, more than 60 genes associated with grain size have been cloned, but the application of grain size genes in rice breeding has not been summarized. This review covers the current advances which can deepen our understanding, such as the key genes for grain size, genetic mechanism behind this trait, breeding application of cloned genes, functional markers for molecular breeding and prospects for future study, which will provide information of molecular breeding for rice breeders.     

英语词汇与大学流行文化

随着经济、科技的飞速发展,社会文明的不断进步,大学校园文化也随之不断演变.作为具有较高知识素养的大学生最具文化变革的适应性,最易接纳社会流行文化潮流的时代变迁,对先进的文化最先敏感地做出反应--追逐时尚,崇尚时髦,从而形成校园文化的亚文化--流行文化.     

我国西部开发的环境和人文优势与发展战略

中国西部大开发作为一项跨世纪的宏伟战略，是一代伟人邓小平先生为中国改革开放事业和中华民族新的崛起而谋篇布局的“两个大局”的另一个“大局”，不仅是国内近年热烈讨论的题目，而且引起国外学者、政界、企业家的广泛关注，人们从各个不同的角度来解读它、认识它、研究它。从我国西部开发与国际大环境的关系入手，着重阐述了我国西部与东部相比存在的优势，并针对优势提出了一系列的发展战略。     

甘肃河西灌区玉米播期对优质小麦与粮饲兼用玉米带田生产能力的影响

优质小麦与粮饲兼用玉米套种是既能生产粮食，又能生产饲料的有效方法，符合农业结构调整的要求。但如果玉米播种过早，小麦与玉米的共生期过长，会出现小麦产量下降，品质变劣等问题。研究了粮饲兼用玉米播期对带田产量和产值的影响，结果表明：将带田玉米安排在4月20日—5月10日播种，总产值最高；期间适当推迟玉米播期至5月5日前后，既不影响粮饲兼用玉米生产，还能提高优质小麦产量，达到增产又增收的目的。     

4、5、7月龄雌性大鼠骨计量学参数的变化及意义

目的：观察4、5和7各月龄SD♀大鼠的骨量、骨形成和骨吸收的变化。方法：21只3．5月龄♀大鼠按随机排列表随机分为3组：4月龄组6只、5月龄组8只、7月龄组7只。大鼠饲养至相应月龄时处死后做骨计量学分析。结果：各组间骨小梁面积百分率(％Tb．Ar)差异无显著性；5月龄组与4月龄组比较，反映骨形成的参数矿化沉积率(MAR)、骨形成率(BFR／BS、BFR／BV、BFR／TV)都降低，7月龄组与4月龄组比较，所有反映骨形成和骨吸收的参数都降低。结论：在4—7月龄期间，SD♀大鼠的骨形成和骨吸收活性下降，但仍保持平衡状态，骨量无显著性变化。     

农用车压带轮式发电机的电子稳压研究

农用车压带轮式永磁交流发电机，把压带轮轮离心式转子外壳设计为一体。转子外壳内侧嵌有多块永磁材料，当转子转动时，磁场旋转，线圈切割磁力线，产生电动势。采用高剩磁强度的永磁材料和新的电子技术以及对发电机结构的创新设计，使发电机输出电压稳定在一定范围内，解决了农用车的低速照明问题。     

Role of central PGE2 on sympathetic excitation in chronic heart failure

AIM: To observe the effect of central prostaglandin E₂ (PGE₂) on sympathetic activation in chronic heart failure (CHF) and to explore the underlying mechanism. METHODS: Male SD rats were subjected to coronary artery ligation to induce heart failure (HF), and the intracerebroventricular infusion was performed by osmotic pump continuously. The rats in sham group and HF group were given artificial cerebrospinal fluid (0.25 μL/h). The rats in HF plus treatment group was given celecoxib (CLB; 20 mg/h). After 4 weeks, the levels of PGE₂ in cerebrospinal fluid (CSF), the sympathetic nerve excitability and cardiac function were measured, and the changes of corticotropin-hormone releasing hormone (CRH)-containing neurons activation and neurotransmitter contents in the hypothalamic paraventricular nucleus (PVN) were also determined. RESULTS: Compared with the sham-operated rats, the HF rats had raised level of PGE₂ in CSF, up-regulated renal sympathetic nerve activity and plasma norepinephrine, increased left ventricular end diastolic pressure, lung-to-body weight and right ventricular-to-body weight ratios, and decreased maximal increase and decreased rate of left ventricular pressure (P<0.05). In addition, the number of CRH positive neurons in PVN and the level of plasma adrenocorticotropic hormone were higher in HF rats than those in sham-operated rats (P<0.05). After administration of CLB into the lateral ventricle of HF rats, the contents of PGE₂ in CSF were significantly reduced, the number of activation CRH neurons in PVN was decreased, the excitability of sympathetic nerves was down-regulated and cardiac function was improved (P<0.05). Compared with the sham-operated rats, the content of glutamic acid in PVN of HF rats was increased, the content of γ-aminobutyric acid and the number of glutamate decarboxylase 67-positive neurons were decreased (P<0.05). After the CLB was given, the above indexes were reversed (P<0.05). CONCLUSION: These findings indicate that in CHF, the increased central PGE₂ may activate CRH-containing PVN neurons and contribute to the augmented sympathetic drive possibly by modulating the neurotransmitters within the PVN.     

空间电场对蔬菜生长及营养成分的影响

以小白菜、小油菜、丝瓜和苦瓜为试材,在防虫网大棚安装空间电场条件下,研究了空间电场对蔬菜的生长和营养成分的影响。结果表明:空间电场提高了小白菜、小油菜的株高和产量,增加了小白菜、丝瓜和苦瓜的茎粗,降低了小白菜、小油菜的根冠比;4种蔬菜的叶绿素、可溶性糖含量下降;小白菜、小油菜和苦瓜的水分含量提高,但是丝瓜的水分含量降低;丝瓜和苦瓜的维生素C含量增加,而小白菜、小油菜的维生素C含量减少;空间电场还降低了小油菜、丝瓜和苦瓜的纤维素含量。总体来说,空间电场能够促进蔬菜的生长,提高蔬菜品质。     

工厂化豆芽成为现代加工食品新宠

伴随着经济、社会特别是科学技术的发展,我国传统家庭作坊式的豆芽生产已被日产60～100t的程序化、机械化、自动化、可调控的现代工厂化生产方式所取代。论述了我国工厂化豆芽产业的发展现状、加工特点、卫生安全、生产规范与市场监管机制,探讨了我国豆芽工厂化生产的可持续发展趋势,以期提升中国芽菜形象,改善人民生活质量,提升国际竞争力。