自然低温对温室不同品种黄瓜耐寒生理及产量的影响

研究和比较了7个黄瓜品种在自然低温下的生理效应及其产量,结果表明:绿宁3号、寒月和津绿3号的根系活力较高;津优30号、永昌9618、绿宁3号和津绿3号的耐低温性较强;津优30号和津绿3号的畸形瓜少,产量高。在根系活力、耐低温性和产量方面,津优30号和津绿3号最好,津优2号和北极星低。     

盐碱地区保护地黄瓜生产技术要点

根据菜农试种结果，较耐盐碱的黄瓜品种有津春三号，锦早三号，北京密刺王，津优2号，爱帝FA，96-18、津绿1号，3号，爱帝FB，顶峰1号等。     

枯萎病菌对不同抗性黄瓜品种苯丙氨酸解氨酶的影响

对抗病品种中农13号、津优3号、津优30号和感病品种中农6号、津研4号、秋棚4号接种黄瓜枯萎病病原菌,测定叶片内苯丙氨酸解氨酶(PAL)活性的动态变化过程。结果表明,苯丙氨酸解氨酶(PAL)活性变化具有周期性,抗病品种出现3次与抗性相关的峰值,感病品种出现两次与抗性有关的峰值。PAL酶活性与抗病性呈正相关关系。PAL酶活性的变化规律不仅与抗性有关,而且与感病与否有关。发病植株的PAL酶活性高于未发病植株。     

远东地区的俄罗斯卫星电视

俄罗斯是世界上的航天大国,也是最早进行卫星通信的国家。早在七十年代末,前苏联研制的“北极星”系列同步通信卫星发射成功,并在99°E定点运行后,我国一些专业单位及卫视爱好者中曾出现安装螺旋式天线、接收下行频率714MHz的北极星(Erran)卫星电视节目热潮。直至八、九十年代,我国尚有不少专业单位安装地面接     

第十一届全国多媒体技术学术会议论文格式

中文题目 (3号黑体 ,居中 )作者姓名 (4号楷体 ,居中 ,多名作者以空格分隔 )作者单位 (5号宋体 ,居中 )摘要 :摘要限 30 0字内 ,摘要内容为 5号楷体关键词 :5号楷体 ;关键词不超过五个 ;以分号隔开1.论文格式论文打印样稿格式 :纸张大小 (页面尺寸 )按 16开 184ｍｍ× 2 6 0ｍｍ纸排版 ,页面设置为 :上 :2 .5厘米 ;下 :2 .5厘米 ;左 :2 .5厘米 ;右 :2厘米。论文总页数不超过 6页 ,不用排页号。2 .字体2 .1一级小标题 (小 4号黑体 )正文采用五号宋体 ,中文标题为三号黑体 ,作者姓名为四号楷体 ,作者单位为五号宋体 ,摘要内容、关键词为五号楷…     

强化栽培条件下不同氮肥运筹对水稻氮素利用及土壤微生物的影响

以高产杂交稻组合两优培九和国稻6号为材料,设置基肥:分蘖肥:穗肥比例分别为50:30:20,60:10:30和40:20:40的不同氮肥管理,研究了强化栽培(SRI)条件下不同氮肥运筹对土壤微生物及植株氮素利用的影响。结果表明,强化栽培下每穗粒数增加,不同处理的结实率差异不明显,不施氮肥千粒重下降。强化栽培下穗肥施入增加,其土壤的铵态氮含量提高。土壤铵态氮以穗分化期最高,在孕穗期、开花灌浆期和成熟期的土壤铵态氮含量较低,基本不足20 mg kg-1;而土壤硝态氮含量穗分化期最低,各处理之间均不到4mg kg-1,而孕穗期达到20mg kg-1以上,开花灌浆期略有下降,成熟期土壤的硝态氮含量高。强化栽培能促进土壤细菌和放线菌数量增加。在穗分化期和孕穗期土壤微生物中放线菌含量最多,细菌次之,真菌量最少;灌浆期和成熟期细菌最多,放线菌次之,真菌量远低于前两者。细菌数以穗分化期较低,孕穗期快速上升,灌浆期略下降,成熟期最高。真菌量开花灌浆期低,成熟期高。土壤放线菌数量在穗分化后基本呈现下降的趋势。后期施氮对放线菌有一定的促进作用。另外,在等量的氮肥水平下,增施穗肥有利于提高籽粒的含氮量,水稻的氮吸收利用率品种间差异较大,强化栽培下两优培九品种氮吸收利用率提高。     

北极星微机系统引导程序改进

配置有双灯30MB 硬盘(其工作指示灯为两个红色发光二极管)的北极星微机在加电引导过程中经常会陷入死锁状态,其中有些机器须通过几次开、关机重新加电引导方可正常工作,有些即使反复开、关机也无法成功地引导系统。厂家对此问题用硬盘辅助软盘冷启动引导后,在不关机的情况下再使用系统引导盘予以解决。此种方法的缺点是每次开机都要用两张软盘片进行两次引导,使用极不方便。我们在对机器的有关硬件电路及引导程序进行分析、研究和多次实验的基础上,对北极星微机的引导程序(在软盘系统磁道上)进行了改进,增加了一些操作,成功地解决了这种北极星微机的系统引导死锁问题。由于改进只是在原引导程序内增加了必要的操作,其他程序并无变动,所以改进后的系统与原系统完全兼容。用修改后的系统引导盘对配置其他类型硬盘的北极星微机同样能进行正确引导,其功能完全保持不变。     

黄瓜花药培养中若干影响因素的研究

利用津春3号黄瓜(Cucumis sativus L.cv Jinchun 3)花药为外植体材料,调查了适于其培养的花药发育时期与外部形态的关系,研究了预处理方式、不同基本培养基类型以及添加植物生长物质2,4-D、NAA、BAP和KT对黄瓜花药培养的愈伤组织诱导和生长的影响等。试验结果表明:津春3号花药最佳培养时期单核中后期的取材标准是花蕾长度为0.6￣1.8cm,花药0.2￣0.3cm,瓣萼等长或者瓣稍长,花瓣淡绿,花药浅绿至白绿;2,4-D是影响黄瓜花药愈伤组织形成的最主要因素,其最适浓度为2￣4mg.L-1;基本培养基类型对花药愈伤组织诱导效果影响显著,以N6培养基适应性最广。     

氮磷钾肥配施对不同品种大白菜硝酸盐累积的影响

通过采用二次饱和D-最优回归设计(311B方案),对氮磷钾肥配施与大白菜硝酸盐累积之间的关系进行研究,建立了能调控大白菜硝酸盐含量的施肥模型。分析表明,不同品种大白菜硝酸盐含量与施肥有很大关系,但品种间存在着较大的差异。在相同施肥处理下,绿星80大白菜硝酸盐含量略低于五福菜的硝酸盐含量。不同品种大白菜硝酸盐累积量和硝酸还原酶活性具有很大的相关性,可作为大白菜体内硝酸盐累积的一项指标。     

氮形态和硫水平对烤烟氮、硫、钾等营养的影响

红壤和潮土培育烤烟,100%铵态氮、100%硝态氮和50%铵氮 50%硝氮等3种氮形态和2种硫施用量的盆栽试验研究表明,增加硝态氮肥供给比例,有利于烤烟生长,烟株叶片干重、株高、干径增加。施硫增加,各叶位全硫含量均显著增加,下部叶片明显累积较多的硫。硝态氮处理红壤和潮土生长烟叶硫含量降低。烟叶氮含量也受供氮形态影响,硝态氮供给比例增加,烟叶全氮含量均较高。供硫增加,烟叶钾含量下降;100%铵氮处理烟叶钾累积较多,NH4 没有抑制K的吸收。     

Effects of morphologies on acetone-sensing properties of tungsten trioxide nanocrystals

In this work, triclinic WO₃ nanoplates and WO₃ nanoparticles were comparatively investigated as sensing materials to detect acetone vapors. Single-crystalline WO₃ nanoplates with large side-to-thickness ratios were synthesized via a topochemical conversion from tungstate-based inorganic-organic hybrid nanobelts, and the WO₃ nanoparticles were obtained by calcining commercial H₂WO₄ powders at 550 °C. The acetone-sensing properties were evaluated by measuring the change in electrical resistance of the WO₃ sensors before and after exposure to acetone vapors with various concentrations. The WO₃ nanoplate sensors showed a high and stable sensitive response to acetone vapors with a concentration range of 2-1000 ppm, and the sensitivity was up to 42 for 1000 ppm of acetone vapor operating at 300 °C. The response and recovery times were as short as 3-10 s and 12-13 s, respectively, for the WO₃ nanoplate sensors when operating at 300 °C. The acetone-sensing performance of the WO₃ nanoplate sensors was more excellent than that of the WO₃ nanoparticle sensors under a similar operating condition. The enhancement of the WO₃ nanoplate sensors in the acetone-sensing property was attributed to the poriferous textures, single-crystalline microstructures and high surface areas of the aggregates consisting of WO₃ nanoplates, which were more favorable in rapid and efficient diffusion of acetone vapors than the WO₃ nanoparticles.     

重构3C服务的O2O模式探析

IT服务成本不断上升及新服务商业模式的出现,促使传统PC厂商在服务市场上不断地变革。首先介绍了3G市场的强势发展,然后分析了消费者对3C服务的需求以及3C服务市场的现状．最后介绍了联想乐享3G平台及其所提供的服务。     

3-卤代吲唑水助质子转移反应机理的理论研究(英文)

在密度泛函B3LYP/6-311G**理论水平上,对气相和水相中3-卤代吲唑瓦变异构体进行几何构型伞自由度优化,获得它们在气相和水相中的几何结构和电子结构,PCM反应场溶剂模型用于水相计算.结果显示在气相和水相中,3.卤代吲唑的N1-H形式比N2-H形式稳定.探讨了不同的3-取代基团和溶剂化效应对互变异构体的几何结构,能量,电荷分布以及互变异构反应活化能的影响等.进一步研究了3-卤代吲唑水催化质子迁移的反应机理,提出了平面五元环的过渡态结构.     

基于反求工程的牙颌模型的建立

目的:利用三维激光扫描仪扫描全牙列模型,对获得的数据进行处理,重构牙颌的三维图形。方法:将获得的三维点云数据进行处理,包括数据平滑、特征提取、数据分割、自由曲面建模等实现牙颌的三维重构。结论:得到牙颌的三维重建数字模型,牙颌模型的建立将极大地提高后期医生设计牙齿的质量与效率。     

Predicting the structures of complexes between phosphoinositide 3-kinase (PI3K) and romidepsin-related compounds for the drug design of PI3K/histone deacetylase dual inhibitors using computational docking and the ligand-based drug design approach

Predictions of the three-dimensional (3D) structures of the complexes between phosphoinositide 3-kinase (PI3K) and two inhibitors were conducted using computational docking and the ligand-based drug design approach. The obtained structures were refined by structural optimizations and molecular dynamics (MD) simulations. The ligands were located deep inside the ligand binding pocket of the p110α subunit of PI3K, and the hydrogen bond formations and hydrophobic effects of the surrounding amino acids were predicted. Although rough structures were obtained for the PI3K–inhibitor complexes before the MD simulations, the refinement of the structures by these simulations clarified the hydrogen bonding patterns of the complexes.     

Development and evaluation of GIS-based ArcPRZM-3 system for spatial modeling of groundwater vulnerability to pesticide contamination

The objectives of this study were to develop and evaluate a GIS-based modeling system called ArcPRZM-3 for spatial modeling of pesticide leaching potential from soil surface towards groundwater. The ArcPRZM-3 was developed by coupling a commonly used FORTRAN-based Pesticide Root Zone Model version 3 (PRZM-3) with user-friendly input and output interfaces through links to GIS using customized programming. A Visual PRZM-3 interface simplifies the entry of model inputs and links to the databases of crops, soils, and pesticides. The ArcPRZM-3 produces user-friendly outputs from the PRZM-3 batch simulations in the form of tables, charts, and maps. The Visual PRZM-3 can be used to run a single simulation for site-specific studies or simultaneous multiple simulations for spatial distributed modeling. The ArcPRZM-3 was applied to simulate maximum dissolved bentazon concentration at 0.75 m soil depth for a period of 2 years. These simulation results were used to develop a health risk map for Woodruff County, Arkansas, based on the U.S. Environmental Protection Agency's Lifetime Health Advisory Level (USEPA-LHA) of bentazon in drinking water. The ArcPRZM-3 was evaluated by comparing the bentazon detection data from monitoring wells from the same area with the predicted bentazon health risk map. The results showed that 100% of the wells where bentazon was detected were within the high risk category based on the ArcPRZM-3 predictions. However, uncertainty in the ArcPRZM-3 model and the timing of groundwater well monitoring could both complicate the interpretations of the ArcPRZM-3 simulation results.     

Use of TRMM in determining the climatic characteristics of rainfall over Bangladesh

Five years of data from 1998 to 2002 of TRMM-3B42 version 5 (V5), 3B43 V5, 3B42 version 6 (V6), 3B43 V6, and the Bangladesh Meteorological Department rain-gauge network were analyzed to understand the climatic characteristics of rainfall over Bangladesh. TRMM-PR 2A25 data were used to obtain the precipitation field of the convection events. Daily rainfall measured by TRMM V5 3B42 was compared to that of rain-gauge values from pre-monsoon to post-monsoon months (March-November). The time sequence patterns of the daily rainfall determined by the V5 3B42 and those from rain gauges were remarkably similar. The spatial and temporal averages of rainfall revealed good estimations of rainfall: during March to November, the V5 3B42- and rain gauge-estimated daily rainfall was 8.12 and 8.34 mm, respectively. In annual scale, TRMM V5 3B42-, V5 3B43-, V6 3B42-, V6 3B43- and rain-gauge estimated rainfall was 6.9, 6.4, 6.6, 6.8 and 7.1 mm/day, respectively. The average percentage of rainy days determined by V5 3B42 data with respect to the rain-gauge value was 96%. TRMM is useful for estimating the average values of rainfall in Bangladesh. The prominent difference between rainfall estimated by rain-gauge and V5 3B42 was found to be period- and location-dependent. The V5 3B42 overestimated the rainfall during the pre-monsoon period and in dry regions but underestimated it during the monsoon period and in wet regions. The reason for the differences according to season and locations is considered to be the vertical cross section of convection obtained by TRMM-PR 2A25 data. The rainfall overestimation in pre-monsoon and underestimation in monsoon period measured by V5 3B42 is reduced to reasonable amount by V6 3B42 and V6 3B43. In this manner, the merit of using TRMM data for climatological studies of rainfall over Bangladesh is shown.