传统螺杆滚筒式脱粒装置的优化设计

本文对传统的螺杆滚筒式脱粒装置的优化设计进行了研究。通过对实验数据作多元二次回归,构造了优化设计模型中的约束条件,利用脱粒分离概率模型构成主要目标函数,建立了以提高凹板分离率为主要目标的优化设计数学模型,编制了相应的优化设计小型程序库。     

风扇滚筒式谷物脱粒装置的研究

本文分析了风扇滚筒式脱粒装置的基本工作原理及影响工作性能的因素。分析和实验结果表明,风扇滚筒脱粒装置叶轮内部的流场,与横流风扇叶轮内部的流场形式基本相同,壳体形状是产生旋涡流场的重要条件,叶片的形状和数目主要影响清选风速的大小。这种脱粒装置结构新颖,简单,重量轻,脱粒能力强,能脱潮湿作物,在我国有较大的推广价值。     

基于离散元法的玉米脱粒过程分析

由脱粒机的CAD模型建立了脱粒机的离散元法分析模型,采用颗粒聚合体方法建立了玉米穗的分析模型,采用接触和连接力学模型计算脱粒过程中的作用力,在此基础上建立了一种分析玉米脱粒过程的新方法和软件。对该新方法和软件进行了实例验证,结果证明了新方法的可行性。     

刚柔耦合式小麦脱粒弓齿设计及试验

为解决小麦脱粒中脱净率低、损伤率高的问题,对小麦脱粒标准弓齿进行创新设计,并对其脱粒界面进行分析。设计刚柔耦合式弓齿小麦脱粒试验台,开展二次回归正交对比试验,损伤率明显降低,降幅最大可达到1.04%,脱净率明显提高,增幅最大可达到4.64%。试验因素对刚柔耦合式弓齿损伤率的影响程度由大到小依次为滚筒转速、喂入量和脱粒间隙,得到损伤率最优作业参数组合:滚筒转速为350 r/min,脱粒间隙为30 mm,喂入量为6 kg/s。试验因素对刚柔耦合式弓齿脱净率的影响程度由大到小依次为滚筒转速、脱粒间隙和喂入量,得到脱净率最优作业参数组合:滚筒转速为600 r/min,脱粒间隙为10 mm,喂入量为3.5 kg/s。     

4GOT—60型小麦割前脱粒联合收割机

本文论述了这种小麦割前脱粒联合收割机的结构特点和性能特点。     

柔性脱粒齿杆与谷物含摩擦打击动力学模型

针对联合收割机脱粒过程,结合Lagrange乘子法和多体系统刚柔耦合理论,建立和分析了脱粒齿杆与谷物含摩擦接触的互作用机理的打击动力学模型。将脱粒过程描述为打击初始时刻、黏滞接触、滑移接触等阶段,引入增减接触约束法,分阶段建立动力学方程,并给出了碰撞搜索算法和状态切换准则。通过自行编制的C语言仿真程序,计算获得了不同脱粒滚筒转速下,脱粒齿打击谷物时的法向打击力、切向揉搓力以及在打击过程中脱粒齿的振动和变形。对纵轴流柔性脱粒滚筒模型进行了EDEM软件仿真和试验验证,结果表明:与普通刚性脱粒齿相比,柔性齿在打击中形成一系列持续的法向打击力和多次反复的微小切向揉搓力,有助于提高脱净率和降低籽粒损伤率。     

基于谷物脱粒中自由籽粒的运动轨迹与速度的拟合分析

以螺旋叶片、刀齿组合式轴流脱粒与分离装置为研究对象,利用Matlab画图分析了稻谷脱粒后籽粒的运动轨迹与速度,通过使用Matlab画出的轨迹与速度图与以往的使用Excel画法画出的图进行了对比分析,结果显示Matlab画出来的图在精确度、清晰度等方面要好于Excel画法。     

4LZ—5型联合收割机脱粒滚筒无级变速器承载能力的试验研究

四平联合收割机厂生产的东风—5型自走式联合收割机的脱粒滚筒虽有变速装置,但调整困难、费时,且仅能在800～1350转/分范围内调整。为使调整方便,提高联合收割机的生产效率,该厂在新产品4LZ—5型联合收割机上设计了一种机械式、快速调节的宽三角带无级变速器。可使滚筒转速在400—1200转/分范围内无级调速,且调整省时、方便,但此种变速器在工作中存在打滑现象,机械工业部下达了为解决此问题的课题。我们接受了此课题,进行了室内台架初步试验和样机田间试验,丢转速问题已明显好转。本文将对滚筒变速装置的理论分析和试验情况加以介绍。     

Research advances of un-symmetric constitutive theory of anisotropic viscoelastic liquids and its hydrodynamic behavior

Research advances of un-symmetric constitutive equation of anisotropic fluid,influence of un-symmetric stress tensor on material functions,vibrational shear flow of the fluid with small amplitudes and rheology of anisotropic suspension were reported.A new concept of simple anisotropic fluid was introduced.On the basis of anisotropic principle,the simple fluid stress behaviour was described by velocity gradient tensor F and spin tensor W instead of velocity gradient tensor D in the classic Leslie-Ericksen continuum theory.Two relaxation times analyzing rheological nature of the fluid and using tensor analysis a general form of the constitutive equation of co-rotational type was introduced.More general model LCP-H for the fluid was developed.The unsymmetry of the shear stress was predicted by the present continuum theory for anisotropic viscoelastic fluid-LC polymer liquids.The influence of the relaxation times on material functions was specially studied.It is important to study the unsteady vibrational rotating flow with small amplitudes,as it is a best way to obtain knowledge of elasticity of the LC polymer,i.e.dynamic viscoelasticity.For the shear-unsymmetric stresses,two shear stresses were obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) were introduced by the constitutive equation which was defined by rotating shear rate introduced by author.For the two stability problems of fluid,such as stability of hydrodynamic flow and orientational motion,were discussed.The results show that the polymer suspension systems exhibit anisotropic character.The PNC systems can exhibit significant shear-thinning effects.For more concentrated polymer nano-suspensions,the first normal stress difference change from positive to negative,which is similar to LC polymer behavior.     

当前民办高校融资难的成因及对策

针对民办高校所需办学经费无国家财政拨款,全部为自筹资金的现状,分析了形成当前民办高校融资难的原因,既有信贷政策、银行方面的因素,也有民办高校自身的因素.提出民办高校要生存,要发展,光靠举办者投入或捐赠以及每年的学费收入是不够的,还需要积极拓展更多融资渠道解决办校融资难的问题.     

脉冲振动预磁器的研究和设计

根据细粒磁性物回收工艺中需要使用预磁器的要求,研究预磁器的工作时序、充放电回路的电器元件特性和电路电压、电流特征.设计的电磁预磁器磁场强度高,能耗低,性价比高.对预磁化电路展开理论计算和推导.首次提出脉冲振动预磁器系统结构,将RLC电路振荡波形转变为振动波形,形成"脉振"高场强,延长了线圈的使用寿命.经实际运行检验,该装置性能稳定,效果好,能耗低,每小时耗电仅0.8 kW,在预磁器领域是一项创新的实用技术.     

城市污水热能资源化的基础研究

作为城市污水热能资源化的基础研究,根据理论分析方法,对有效利用城市污水所赋存的热能时,其节能效果和对减轻大气污染的作用进行了若干分析和探讨.分别计算了流量为1 m3/s时城市污水赋存的热量,以及采暖面积为1万m2时所需的城市污水及赋存的热量,与空调、锅炉相比产生相同热量时的一次能和二次能的消减量,以及相应条件下的污染物年间(采暖期)消减量等.     

Vibrational shear flow of anisotropic viscoelastic fluid with small amplitudes

Using the constitutive equation of co-rotational derivative type for anisotropic viscoelastic fluid-liquid crystalline(LC),polymer liquids was developed.Two relaxation times are introduced in the equation:λn represents relaxation of the normal-symmetric stress components;λs represents relaxation of the shear-unsymmetric stress components.A vibrational rotating flow in gap between cylinders with small amplitudes is studied for the anisotropic viscoelastic fluid-liquid crystalline polymer.The time-dependent constitutive equation are linearized with respect to parameter of small amplitude.For the normal-symmetric part of stress tensor analytical expression of the shear stress is obtained by the constitutive equation.The complex viscosity,complex shear modulus,dynamic and imaginary viscosities,storage modulus and loss modulus are obtained for the normal-symmetric stress case which are defined by the common shear rate.For the shear-unsymmetric stress part,two shear stresses are obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) are given by the constitutive equation which are defined by rotating shear rate introduced by author.The dynamic and imaginary viscosities,storage modulus and loss modulus are given for each complex viscosities and complex shear modulus.Using the constituive equation the rotating flow with small amplitudes in gap between two coaxial cylinders is studied.     

科技期刊版式设计略谈

对科技期刊版式设计中的标题、插图与空白的处置进行了分析探讨,认为科技期刊版式设计在总体上应是追求格式一致与节奏变化的统一,整体性与连贯性的统一.布局合理的版式设计带给期刊的是整体的和谐美,别具风格的版式设计标志着期刊的个性特征.     

利用双折射晶体实现双偏振光叠加的教学研究

利用晶体的双折射现象和它的基本性质,采用现代光纤和CCD摄像放大技术手段研究了双偏振光的叠加和干涉现象,讨论了学生在教学中不易理解的难点问题.     

玉米中转基因成分的定性PCR检测

利用改良 CTAB 法提取玉米产品的基因组 DNA,应用 PCR 检测方法,并以玉米特异性内源基因 IVR 为内参,花椰菜花叶病毒 35S 启动子(CaMV35S 启动子)、农杆茵胭脂碱合成酶终止子(NOS终止子)为靶基因检测玉米中是否存在转基因成分.实验结果表明,有些玉米样品中存在转基因成分,表明市场上存在未经标识的转基因玉米及其加工品.