Simulation for Dynamical Characteristics of the System with the 2T Air Hydraulic Hammer

The detailed analysis has been done for the dynamical characteristics of the system with the 2T air hydraulic hammer.The computer digital simulation has been done for the elevating course of the air hydraulic hammer using the method of the power bond graph and the states space analysis.The results obtained from digital simulation are agreeable with the experimental results.     

An Experimental Study of the Optimal Jet Position on Water Jet Assisted Drag Bit During Rock Cutting

The tests for the effects of jet position on drag bit cutting process were described. The influence of jet position on rock chips formed ahead of bit was analyzed. And the effects of cutting depth,bit velocity on bit force reductions were discussed. One of the most interesting results is that the water jet has the largest effect on drag bit forces when it is directed towards the center beneath drag bit.     

Torsional Vibration Simulation Analysis of Drilling String and Rock Bit

In this paper,the method of establishing the torsional vibration model of drilling string and rock bit and the process of simulation analysis are introduced.The interaction between bit and rock and elastic deformation of drilling string in the process of petroleum drilling which caused the torsional vibration of the drilling string and rock bit is main considered in establishing the model.The torsional model is solved by difference method.Based on the models,the simulation analysis software of drilling string and rock bit is designed,and simulation calculation and analysis of the tortional vibration of drilling string and rock bit under different conditions are computed,and the dynamic behavior and kinetics regularity of drilling string and rock bit in drilling are obtained.     

Powertrain parameter design for the electric vehicle with taking the energy consumption of air conditioner into consideration

On the basis of considering the influence of air conditioner on vehicle performance,the parameter determination of the power train composed of a battery,a traction motor and a two-speed transmission of an electric car is carried out. To ensure the economy of operation,a shifting strategy with a principle which emphasizes the high work efficiency of the power train is drawn up and the gear ratios are corrected aiming at the least energy cost over the drive cycle. The simulation results indicate that the designed parameters meet the requirements moderately and the driving range is extended by 5.28% when the air conditioner is turned off and 4.29% when turned on,compared with the initial results through the correction of the gear ratios.     

Influence of rain on AC discharge characteristic of rod-plane(rod-rod) air gap

As flashover accidents because of strong wind and storm frequently appear in our country, storms are thought to be one cause of flashover between tower and conducting wires in transmission lines.The influence of rainfall intensity,rainwater resistivity and air temperature on AC discharge characteristic of rod-plane(rod-rod) air gap is mainly investigated.The experimental result shows that,rainfall intensity and rainwater resistivity can reduce AC discharge voltage of rod-plane(rod-rod) air gap,and rainfall intensity has the most obvious effect on AC discharge voltage of rod-plane air gap;when rainfall intensity ranges from 2 to 14 mm/min,AC discharge voltage maximum reduction of 0.4,0.6,0.7 m rod-plane gap is respectively 6.73%,6.54%,6.02%,and maximum reduction of rod-rod gap is respectively 2.66％,3.22%,3.07%;the influence of rainfall intensity on AC discharge voltage of rod-plane is bigger than rod-rod’s;AC discharge voltage of rod-plane air gap increases with the increase of air temperature,and the maximum amplitude is 7.03%.     

烟粉虱种群数量消长规律与模型测报技术研究

为了揭示烟粉虱种群数量季节性消长规律,提高其预测预报水平,2006年2月至2007年2月利用塑料黄板涂抹机油在浙江临海城郊蔬菜基地系统诱测烟粉虱成虫消长情况,结果表明烟粉虱种群数量消长呈双峰型曲线变化,并分析了烟粉虱种群消长特性,以及与气象、耕作条件的相关性,建立了8种数学预测模型。应用这些模型可提前反映全年36个旬期的成虫数量变化动态,可进行全年灾变预警以及各旬期的预测预报,经检验预测吻合度达60%。对提高烟粉虱监测预警与综合防治水平具有重要指导意义     

油菜生育期动态模拟模型的构建

在13个不同熟期甘蓝型油菜品种的2年大田试验中,调查不同播期条件下各品种的生育进程及发育状态。依据油菜生理发育时间恒定原理、生理生态理论及各生育阶段与温度、光周期等外部环境关系,采用Logistic曲线描述油菜光周期效应,谐波分析法分析气温昼夜变化,分段正弦指数函数分析热效应和低温春化效应,结合上述因素构建油菜生育期动态模拟模型;确定模型光周期敏感因子、温度敏感性、生理春化时间和角果期因子4个遗传参数;模型的检验分析表明,对不同播期模拟值与观测值的根均方差平均值为2.67 d,对不同品种模拟值与观测值的根均方差平均值为3.74 d;4个遗传参数值对13个油菜品种聚类分析的结果符合品种特性。因此,该模型在一定范围内可准确揭示油菜对温、光的反应规律,具有较强的可靠性和预测性。     

Simulation of Motion Control System Based on the 2nd Generation Scanning for X-Ray Industrial Computerized Tomography(X-CT)

The second-generation control system of scanning motion of industrial computerized tomography(ICT) systems is that the scanning motion is divided into translation and rotation. This paper only focuses on rotation. After acquiring the transferred function of the rotation based on the features of the system, we simulate the system to get the parameters of the motion in the field of time and frequency with Matlab, and modify it to some extent in order to change its capability of response for getting the best control.     

氮磷钾施用水平与莴苣产量关系的拟合分析

摘要：本研究采用“3414” 试验设计方案,研究了13种（不含空白）不同氮、磷、钾搭配施肥方案下,各处理组合莴苣植株对氮、磷、钾的吸收量,获得莴苣每形成1000 Kg生物产量,需从土壤吸收N 1.21-2.26 Kg,平均 1.88Kg;P2O5 0.57-0.81Kg,平均0.64Kg;K2O 2.97-5.09Kg,平均 3.92Kg,氮、磷、钾的吸收比例为3：1：6;采用拟合法分析了单纯施用一种营养、两种营养元素配合下,施肥与产量的关系,提出了莴苣“控氮磷增钾” 的施肥原则。从提高肥料利用率,减少肥料流失的角度对于减轻农业面源污染具有非常重要的意义。     

不同预处理方式对萝卜小孢子活力的影响

研究温度(低温和高温)及培养基(无碳源、甘露醇及秋水仙素)预处理对4个萝卜基因型小孢子活力的影响,得出的结果是:4℃低温条件下处理3 d的小孢子可保持较高的存活率,36℃高温处理后的小孢子存活率明显低于对照;加入蔗糖的培养基对提高小孢子存活率作用明显;甘露醇及秋水仙素处理也能提高萝卜小孢子存活率,其合适的浓度在不同萝卜基因型中存在差异。     

空气负(氧)离子研究的知识图谱

归纳空气负(氧)离子研究进展和前沿热点,旨在为未来研究提供参考.基于Web of Science核心数据库以air negative oxygen ion为检索对象,获取2002-2019年收录的空气负(氧)离子文献,并通过知识图谱展现18年间其发展历程.结果 表明,2002-2019年Web of Science...     

密度对七星瓢虫不同虫态生存的影响

为探究不同容积-密度组合饲养七星瓢虫对其各历期存活率及成虫重量的影响,本研究在温度25℃、相对湿度60-80%,光照周期10L:14D条件下,设置3种容积 (1000ml、750ml、500ml)与3种密度 (25头、35头、45头)组合下观察统计不同历期七星瓢虫存活数,并对成虫称重。试验结果表明,密度-容积组合对低龄期幼虫存活的影响显著高于其它历期(P<0.05)。其中,1-2龄在500ml下的存活率25头、35头、45头均显著的低于750ml下的3种密度及1000ml-25头,依次为57.33%,48.57%,40.74%,其存活率的最佳容积与密度组合为750ml-35头,存活率达到88.57%;在3龄、4龄、蛹期及成虫时,其最佳饲养组合分别为500ml-25头、1000ml-25头、750ml-35头及750ml-35头,其存活率分别为93.33%、94.49%、92.38%和97.78%,但该最优组合在统计学上与其它组合无显著差异(P>0.05);对初羽化成虫称重表明,除1000ml 25与45头/盒间有显著差异外(P<0.05),其余体积与密度组合下成虫体重均无显著差异 (P>0.05)。综上所述,在七星瓢虫规模化饲养中,幼虫阶段的低龄期存活率受密度及容器大小影响严重,当密度为25-45头时,应避免1-2龄阶段在小于500ml条件下饲养,对七星瓢虫规模化饲养条件的设置提供一定理论支持。     

冷藏对菜蚜茧蜂羽化率及寿命的影响研究

为了明确不同温度、不同僵化天数以及冷藏时间对菜蚜茧蜂羽化率及寿命的影响,找出菜蚜茧蜂最适冷藏条件。实验在不同温度(2、3、4、5、6℃)下冷藏不同僵化程度（僵化1、2、3、4、5天）的菜蚜茧蜂僵蚜5、15、25天。结果显示：随冷藏时间的延长菜蚜茧蜂的羽化率有所降低;僵化4、5天的僵蚜更耐冷藏,4~5℃较适合菜蚜茧蜂低温冷藏。6℃时有部分虫体在冷藏过程中羽化。冷藏期为5、15天时,可存活2~3天。冷藏期为25天时,寿命为1~2天。因此,菜蚜茧蜂最适宜在僵化4~5天时,于4~5℃冷藏。     

A Three Dimensional Torso Model for the Numerical Simulation of ECG--Forward Problem of ECG(1)

In this paper,a numerical model of a three dimensional human torso has been presented.In this model,the torso part including anisotropic muscle layers has been discretized by means of the finite element method(FEM).The rest of torso have been divided into the surface elements by the boundary element method(BEM).This discretized model can be used in the field such as the forward problem and the inverse problem of the electrocardiogram(ECG).     

RESEARCH ON THE STRUCTURE OF DOWNFLOW WASTEW ATER DISTRIBUTORS IN AN ANAEROBIC FLUIDIZED BED(I) (With the object of minimum return flow rate)

In this paper, the. optmization structure of downflow wastewater distributor in an anaerobic fluidized bed is studied by means of orthogonal test and statistical analysis with the object of minimum return flow rate.The sequence of importance, the prominent factors affecting performance of the distributor, and the optimum structure of downflow wastewater distributors are obtained.     

水稻重组自交群体灌浆速率的遗传分析

为了解籽粒灌浆和籽粒产量相关性状的遗传基础,为改良籽粒灌浆特性提供依据,以小穗小粒型水稻Milyang 46和大穗大粒型FJCD建立的包含130个家系的F10重组自交系为研究材料,分析福建省武夷山和莆田环境下水稻籽粒灌浆速率,并结合已构建的遗传图谱进行QTL动态定位及环境互作研究。QTL定位分析共检测到10个加性QTL,位于1、2、5、6、7号染色体上,对表型变异贡献率0.92%~24.41%。同时,qGR-1-4、qGR-2-1、qGR-5-9及qGR-6-7均存在显著的环境互作效应,体现了一因多效。qGR-6-7和qGR-6-8加性均可解释表型变异24.41%。另外,qGR-6-7的环境互作效应可解释表型变异贡献率9.33%。     

不同Zn2+活度对水稻根和叶生长生理特性的影响

在营养液水培条件下,研究了不同Zn2+活度((pZn2+9.7, pZn2+11.0和pZn2+> 11.5 )对水稻根叶的生长发育和若干生理特性的影响。结果表明：低Zn2+活度下,对水稻秧苗的出叶速度减慢,但不同基因型间存在明显差异,极度缺锌(pZn2+>11.5)时,敏感品种只生长3.5叶,而耐低锌品种生长4.5叶左右;轻度缺锌或缺锌初期叶绿素含量上升和     

不同温敏型两系杂交稻F1育性温光效应的研究

采用盆栽方式,通过人为疏枝减库平衡库源关系,研究短日低温、高温,长日低温、高温条件下不同温敏型两系杂交稻F1育性(受精率)的变化。结果表明：1,低温敏型F1育性稳定,不论长日或短日都对温度变化表现钝感。高温敏型及反向温敏型F1育性对温度的反应与其母本基本一致;2,温度高低不是影响不同温敏型F1育性变化的唯一因子     

外源5-氨基乙酰丙酸(ALA)对低温胁迫下垂穗披碱草种子萌发及生长的影响

以2份垂穗披碱草种子(北京和申扎)为试验材料,采用不同浓度5-氨基乙酰丙酸(ALA,0 mg/L、0.1 mg/L、1.0mg/L、5.0 mg/L、10.0 mg/L)浸种24 h后,研究外源5-氨基乙酰丙酸对低温胁迫下垂穗披碱草种子萌发及幼苗生长的影响。结果表明:低温胁迫(5℃)下,0.1~1.0 mg/L ALA浸种后,显著地提高了北京和申扎垂穗披碱草种子的发芽率、发芽指数及幼苗的根长、苗长和鲜重,降低了膜透性以及MDA含量,而高浓度ALA浸种(5.0 mg/L和10.0 mg/L)降低了它们的发芽率和发芽指数。研究结果表明,5-氨基乙酰丙酸能够促进低温下垂穗披碱草种子萌发和幼苗的生长,其中1.0 mg/L ALA浸种效果最好。