考虑剪切变形影响的桩基m法计算理论

考虑桩基的剪切变形影响,利用单广义位移深梁理论,建立了桩基m法的计算方法,导出了水平位移、转角、弯矩和剪力的初参数表达式和无量纲参数函数的统一表达式,根据桩底边界条件建立了初参数解的计算公式;给出了无量纲参数函数随换算深度和弯剪刚度比的变化图形。研究表明,换算深度小于3.0时,弯剪刚度比对无量纲参数函数影响较小,换算深度大于4.0时,弯剪刚度比对无量纲参数函数影响的趋势非常明显,桩基剪切变形的影响程度与桩的边界条件有关。算例结果表明,桩身的剪切变形有增大桩顶水平位移、提高弯矩零点位置、改变弯矩分布特征、扩大桩侧土压力大小等影响。     

农田土壤硝态氮淋洗影响因素及阻控对策研究进展

农田土壤中硝态氮淋洗是氮肥损失的重要途径之一,也是地下水污染的主要来源,因此得到了全世界的广泛关注。分析了影响农田土壤硝态氮淋洗的人为因素和自然因素,并综述了包括氮肥管理、水分管理、填闲作物及轮作、作物品种培育等方面阻控对策研究进展,以期为作物优质高产和环境友好的氮肥综合管理研究提供信息。     

design of a closed loop control virtual test for vehicle handling stability

In an effort to address the high risks and qualification demands of test drivers, a vehicle model and a driver model were built based on ADAMS/CAR, an advanced block of ADAMS. The steering efforts test procedure was designed according to the national standard GB/T 6223.5—1994. A virtual test was performed in ADAMS, and the results calculated. The results show that the driver model possesses a strong capacity to charge the vehicle model. The virtual test results satisfy the evaluation index, indicating the virtual test can be used to test and improve vehicle performance.     

Rockfalls Movement mode and Movement Features by Field Tests

Field test is a better way to find sensitive factors, explore movement law and get movement parameters in rockfall study. To analyze the influence of rockfall shape, size and movement patterns on its movement law, 112 rockfall field tests are implemented. Statistics of horizontal movement distance and velocity under the influence of rockfall shape, size, and rebounce time are conducted. The results show that no matter what shape rockfall is, its movement mode are limited to rolling and bouncing, and there is no apparent sliding section. And about 59% test rockfalls are intercepted by the platform of slope and roadside trench which can be selected as passive mitigation measures. The spherical, square and short cylinder rockfalls have longer horizontal movement distance, bigger faster velocity, and the same movement features. But the rectangular and sheet rockfalls have poor movement capacity, and their movement features are similar to that of the long cylinder rockfall. To sum up, the cylinder assumption for rockfall movement calculation is more realistic. The rockfalls with smaller quality have the worse movement capacity but the greater randomness. When the rockfalls roll mainly, the kinetic energy loss is serious, and both horizontal movement distance and velocity are greater when it bounces mainly. Furthermore, when rockfall collides with the slope surface, its movement parameters and direction will change dramatically.     

Remote on-line vibration test for multi-megawatt wind turbine

As the key components of the wind turbine transmission, wind turbine drivetrain is always working under the complex and time-varing conditions, like flexible tower supporting, variable wind and changing load. Thus drivetrain is no wonder the weakest part for the wind turbine and its vibration characteristics determine the reliability and operating life of the wind turbine. This paper proposes a remote on-line test method for drivetrain vibration based on an intellectual monitoring unit named WindCon. The vibration characteristics of the commonly used multi-megawatt wind turbine are summoned through analyzing the collected data in different working conditions. The wind field results show that the vibration of drivetrain is relatively complex, and it’s mainly manifested as a combination vibration of torsion, bending, and waving. Main frequencies of vibration of mainshaft, gearbox, and other parts in drivetrain are gear meshing frequencies and shaft rotating frequencies of each transmission stage especially high speed stage, and are accompanied by rotating frequencies modulation.     

4种药剂对二斑叶螨的室内毒力和田间防效

采用玻片浸渍法测定了依维菌素等4种药剂对二斑叶螨雌成螨的室内毒力,并进行了防治二斑叶螨的田间药效试验。室内测定结果表明,几种药剂对二斑叶螨的毒力顺序为:依维菌素>甲氰菊酯>高效氯氟氰菊酯>螺虫乙酯,其中依维菌素对二斑叶螨的室内毒力最高,其LC50值为0.01 mg/L。田间试验结果表明,0.5%依维菌素乳油9、18 g/hm²用量,药后3、7、10天对二斑叶螨的防治效果在90%以上,可作为防治二斑叶螨雌成螨的首选药剂。     

氟吡菌酰胺防治瓜类及草莓白粉病田间试验

为了筛选高效、安全的白粉病化学防治药剂,通过田间药效试验进行药剂筛选。试验结果表明,分别在药后7天和14天,氟吡菌酰胺防治甜瓜上白粉病的效果最高,防效均在95%以上。与之相比较,防治黄瓜上白粉病和草莓上的白粉病效果稍低,其防效也在90%以上。研究表明,氟吡菌酰胺防治白粉病效果良好、持效期长,是防治黄瓜、甜瓜、草莓白粉病的一种新型良好杀菌剂。     

Site selection for a measuring and controlling device of initial phase based on maximum elevation angle

We introduced a site selection method based on the modified maximum elevation angle intended for mountains possibly affecting the measurement and control of the initial phase in a launching port located in mountainous areas. To use the former analysis results, the method, along the helices whose center is the launcher's project point, analyze each point's visibility on the helices. The visible area can be obtained by comparing the visibility at each moment in the initial phase. Finally, there can be three points in the above visible area with distances longer than required.     

甘薯小象甲防治药剂的筛选及田间药效

为了筛选适合湛江等热带地区防治甘薯小象甲的高效、经济、安全药剂,以甘薯小象甲成虫为实验材料,对12种药剂进行室内毒力测定、盆栽药效试验和田间药效试验筛选.结果 表明,3.2％阿维菌素乳油、20％虫酰肼悬浮剂、5％啶虫脒乳油和16％虫肼·茚虫威乳油4种药剂对湛江地区甘薯小象甲防治效果较好,其中3.2％阿维菌素乳油和20％...     

3种生物杀虫剂防治烟草烟粉虱的室内毒力及田间药效试验

为了筛选控制烟草烟粉虱的有效药剂,采用3种生物杀虫剂对烟草烟粉虱进行室内毒力测定及田间药效试验。室内毒力测定结果表明,对烟草烟粉虱的毒力顺序为：0.5%依维菌素乳油＞0.5%藜芦碱可溶液剂＞6.0%鱼藤酮微乳剂,其LC50值分别为1.396 mg/L、5.083 mg/L、12.287 mg/L,显著优于对照药剂高效氯氟氰菊酯(LC50值为30.67 mg/L)。田间药效试验结果表明,6.0%鱼藤酮微乳剂、0.5%依维菌素乳油,0.5%藜芦碱可溶液剂稀释2000倍液喷雾处理后,药后3d、7d、14d更正防效对烟草烟粉虱持效性较好,更正防效达70﹪以上。因此,3种生物杀虫剂对烟田未产生药害,烟草植株生长安全,可在生产上进一步推广应用。     

Herbicide resistant transgenic flax field test: Agronomic performance in normal and sulfonylurea-containing soils

Summary Two linseed flax (Linum usitatissimum) lines transformed with a mutant Arabidopsis ALS gene conferring resistance to sulfonylurea herbicides were tested in a replicated, randomized field test against its nontransformed commercial cultivar parent (cv. NorLin) in normal soil and in soil containing the commonly used sulfonylurea herbicides chlorsulfuron (Glean^®) or metsulfuron methyl (Ally^®). There were no significant differences between the transgenic lines and the parent for any agronomic trait measured in untreated soil, indicating that there is no detrimental effect of T-DNA or foreign gene expression. Similarly, there were no significant differences for performance of the transgenic lines between the untreated and the herbicide treated soils, indicating that the transferred gene does confer a field level of tolerance to the flax. The control NorLin was devastated by the presence of the herbicides in the soil.Abbreviation ALS acetolactate synthase     

猕猴桃溃疡病高效防治药剂的筛选及田间应用评价

筛选高效的猕猴桃溃疡病防治药剂和配套的田间施药技术,为病害的防治提供有效措施和技术指导,以提升植保水平和农产品品质。采用管碟法对10种试验药剂进行了室内抑菌初筛,田间试验中采用单因素随机区组设计,同时设置清水对照。结果表明:(1)室内筛选:从10种药剂中筛选出4种抑菌效果较好的药剂,分别为80%乙蒜素、0.15%四霉素、3%中生菌素和98%盐酸土霉素,抑菌圈直径均大于40 mm,抑菌率分别为70.49%、70.49%、68.85%、65.57%,透明度均在+++以上,其中80%乙蒜素抑菌效果最好,对猕猴桃溃疡病菌的抑制中浓度EC₅₀为0.4978 mg/L。(2)田间防效:稀释400倍的乙蒜素防效最高,达68.77%;采用灌根+注干的施药方式防效最好,达到71.41%。80%乙蒜素及配套的使用方法可为猕猴桃溃疡病防治提供新手段,具有较好的应用前景和推广价值。     

香蕉细菌性软腐病防控药剂筛选及田间应用效果评价

为筛选出香蕉细菌性软腐病的有效防控药剂,通过室内抑菌、盆栽防效以及大田试验,系统开展香蕉细菌性软腐病防治药剂筛选,为生产上的防治提供参考和科学依据。采用含毒介质法中的最低抑制浓度法,测定包括抗生素类和非抗生素类等11种杀菌剂对香蕉细菌性软腐病菌的室内抑菌效果,筛选具有抑菌效果的10种药剂进行盆栽试验,并对4种盆栽试验防治效果较好的药剂开展田间防治试验。结果表明：（1）11种药剂中抗生素类药剂以四霉素抑菌效果较好,抑菌最低有效浓度为1.74μg/mL,其次为硫酸链霉素、春雷霉素、中生菌素,抑菌最低有效浓度分别为9.10、29.50、89.10μg/mL;非抗生素类药剂以铜制剂类抑菌效果较好,噻霉酮抑菌最低有效浓度为89.55μg/mL,其次为王铜、噻菌铜,抑菌最低有效浓度分别为445.00、595.00μg/mL。（2）春雷霉素的盆栽防治效果较好,防效达67.97%,其次为噻霉酮、中生菌素、噻菌铜,防效分别为64.58%、63.53%、61.83%。（3）春雷霉素防治效果达90.19%,其次为噻霉酮、中生菌素、噻菌铜,防治效果分别为89.84%、84.60%、74.59%。4种药剂对香蕉...     

防治烟蓟马的生物源农药筛选及其对解毒酶活性影响

[目的]筛选防治烟蓟马(Thripstabaci Lindeman)的高效生物源农药,探究其对烟蓟马3种主要解毒酶细胞色素P450单加氧酶(Cytochrome P450 monooxygenase,P450)、谷胱甘肽S-转移酶(Glutathione S-transferase,GST)和羧酸酯酶(Carboxyl...     

战骨ISSR-PCR反应条件的筛选与优化

采用正交和单因素试验设计方法,研究Mg2+、dNTP、Taq DNA聚合酶、引物、模板DNA、退火温度及循环次数对ISSR-PCR扩增效果的影响,建立并优化战骨ISSR-PCR反应体系和程序,即25μl的体系中合Mg2+ 2.0 mmol/L,dNTP 0.2 mmol/L,TaqDNA聚合酶1.0U,引物0.8μmol/L,模板DNA 50 ng,10×Buffer 2.5μl.退火温度、循环次数分别为52℃、45次.结论:结合正交和单因素试验可快速建立ISSR-PCR反应体系.该体系稳定、可靠,可用于战骨遗传多样性分析.     

Research and development of a testing control system for a heavy duty vehicle automatic mechanical transmission test bench

Automatic mechanical transmissions (AMT) are suitable for use in heavy duty vehicles. Bench testing is an important task of the research and development. Many objectives, such as AMT performance testing, matching AMTs with engines, and optimizing control rules, can be achieved through bench testing, thereby laying a foundation for AMT application. An AMT testing bench is built up based on a developed AMT. By analyzing the performance requirements of AMT bench testing for heavy duty vehicles, a testing controlling system scheme is proposed and methods of data acquisition and communication are analyzed. Control methods for actuators are proposed based on analyzing the characteristics of AMT actuators. A testing control program for AMT bench testing is developed based on the Delphi platform. The entire bench testing system possesses advances test functions.     

果蔬谷物皮渣湿法切割粉碎关键参数与相关流场的研究

为提高生产果蔬谷物饮品中原料的利用率,分析了果蔬谷物皮渣湿法高速切割超细粉碎机理与关键设备技术。为了直观描述与分析果蔬谷物皮渣在切割粉碎腔内的转子刀头形式、定子刀片偏转角度、转子刀头转速以及定子刀片个数对流场的影响情况,运用Fluent软件对果蔬谷物皮渣在切割粉碎腔内流场进行可视化分析与研究,得到相关结构参数与粉碎流场的分布状态,为高纤维果蔬谷物饮品开发与清洁化生产提供一定的技术支持。     

Use of immature seed germination and single seed descent for rapid genetic gains in pigeonpea

Long duration required for generation advancement in pigeonpea [Cajanus cajan (L.) Millsp] is one of the major bottlenecks in realizing rapid genetic gains. Therefore, a technology for rapid generation turnover is warranted to facilitate the development of new cultivars and recombinant inbred lines. Breeding of early‐maturing cultivars has now opened up the possibility of rapid generation advance (RGA) in this crop. This paper reports the development of an RGA technology that integrates the germination of immature seeds with single seed descent method of breeding. The results showed that immature 35‐day‐old seeds can be used successfully to turn over a generation of pigeonpea with 100% seed germination. These way 3/4 successive generations can be grown within a year. The methodology presented in this study will accelerate the breeding process for breeding cultivars and develop rapidly the materials required for genomics research in pigeonpea.     

Evaluation of Maize Germplasm for Tolerance to Low Temperature Stress under Field and Laboratory Conditions

Sixty-four inbred lines of maize ( Zea mays L.) were evaluated for their tolerance to low temperature stress in three experiments at Punjab Agricultural University, Ludhiana. All the 64 inbred lines were evaluated under laboratory conditions. Forty-four of these were also studied under field conditions. In the laboratory test the materials were exposed for four hours to 1, 0, −1, −2, −3 and −3.5°C on six successive nights. Significant genotypic differences were observed for freezing injury in laboratory test and for frost and non-freezing (yellowing) injuries in field evaluation. Expression of frost injury under field condition and freezing injury in laboratory test at −2, −3 and −3.5 °C showed positive correlation in one experiment. The range and mean square for freezing injury of inbred lines were the largest either at −3 or at −3.5°C. The correlation of yellowing with frost injury in field and freezing injury in laboratory at −3 and 3.5°C was not significant suggesting the lack of association between yellowing and frost/freezing injury.