宰后牛骨骼肌肉生物电阻抗特性初探

用四电极法在多频(5-200kHz)条件下对宰后牛骨骼肌肉的电阻抗特性进行了初步的研究。发现牛骨骼肌生物电阻抗与肌肉纤维方向、电流信号频率和宰后肌肉所经历的阶段有关。横向电阻(沿垂直于骨骼肌纤维方向)大于纵向电阻(沿骨骼肌纤维方向),而且受电流信号频率的影响较明显,尤其是在5￣100kHz范围内。牛宰后生物电阻抗的变化与pH值的变化有一定的相关性。     

盐碱地区不同观赏树种电阻抗图谱参数和电导率的变化

在盐碱地区对4-6月生长期的两种不同观赏树种垂榆（Ulmus pumila var. pendula）和女贞（Ligustrum lucidum）进行电导率及电阻抗测定,分析春季和初夏生长期间在盐碱地区这两种不同观赏树种电导率和电阻抗图谱参数的变化。结果表明：在自然的盐碱环境条件下生长的垂榆和女贞,随着生长期的延长其电导率和电阻抗图谱参数均出现规律性变化,垂榆和女贞的叶片电导率均表现为先增加、后减小的变化趋势,茎均表现为先减小、后增加的变化趋势;两种观赏树种叶片的胞外电阻率表现为先增加、后减小的变化趋势,茎的胞外电阻率和弛豫时间表现为不断增加或先增加、后减小的变化趋势。相关分析表明应用电阻抗图谱参数可以表征观赏树种受盐胁迫的程度,为垂榆和女贞耐盐碱程度的电阻抗诊断提供初步的参数。     

短日照对金叶女贞茎抗寒性和电阻抗图谱参数的影响

为探明短日照处理对金叶女贞(Ligustrum vicaryi)茎抗寒性和电阻抗图谱参数的影响,找出抗寒性和电阻抗图谱参数的关系,完善电阻抗图谱法测定植物抗寒性技术,在抗寒锻炼前,对金叶女贞当年生扦插苗进行短日照处理,对照为自然日照长度;然后分别用电阻抗图谱法和电导法估测其抗寒性,并进行比较分析。结果表明:短日照处理能在抗寒锻炼期间使金叶女贞茎的抗寒性提高3℃左右,金叶女贞茎的抗寒性与未冷冻处理茎的弛豫时间τ、冷冻处理后茎的胞外电阻率re、含水量之间均存在较高的相关性。电阻抗图谱法是一种测定植物抗寒性,尤其是估测不经冷冻处理样本抗寒性的可行的方法。     

基于传输线网络的特高压变电站智能组件端口电磁骚扰的建模仿真

随着智能化GIS设备的发展,GIS设备上集成了大量电子设备。GIS设备开关操作产生的特快速瞬态电磁过程主要经由“传感器—二次电缆—智能组件”这段电路对电子设备产生电磁影响。笔者首先基于传输线网络理论建立了开关操作产生的地电位升对“传感器—二次电缆—智能组件”回路的耦合计算模型,然后通过验证实验证明了计算模型的有效性和准确性,最后对不同屏蔽层接地方式下的各传感器端口和智能组件各端口及端口间的骚扰电压进行了仿真研究。计算结果显示,各骚扰电压受接地方式的影响较大;通过选择合适的接地方式,可以有效地抑制开关操作电磁骚扰。     

基于灰色系统理论水产养殖投入产出优化模型研究

建立了基于灰色系统理论的投入产出优化模型,并将其运用于水产养殖的投入产出分析。在获得投入、产出系数后,利用GM（1,1）模型预测最终水产养殖的需求量（上下限）、资源保证程度（最高量和最低量）;然后通过定性分析与定量研究,对未来各阶段投入产出系数进行修正和设计灰色投入产出优化模型;最后进行模型计算,取得多种可供选择的优化方案并进行综合论证评价后确定最满意方案。该模型做到了方法互补,求解比较容易而且便于灰靶决策。     

农业物料介电特性的测试及影响

在进行农业物料相关品质检测与加工时,往往需要测定其许多参数,其中介电特性随物料种类的不同而体现出差异性,可以根据这一特性对不同物料的物性进行表达。此外,同种物料本身的介电特性又与许多因素有关,利用影响因素与介电特性的相关性,可以对物料的品质因素进行判定,对加工过程进行实时监测和优化控制。综述分析了国内外农业物料介电特性的相关研究,介绍了生物电学模型及介电特性的各种测试方法,并概括了各种测试方法的优缺点,总结了不同方法的适用条件以及受约因素。综述农业物料(特别是果蔬)的介电特性受到电磁场参数、温度、物料外形参数以及水和离子行为的影响,为研究果蔬介电特性在果蔬干燥、保鲜、品质检测等方面的应用提供参考。     

超薄层等电聚焦电泳技术鉴定玉米F1代纯度

本文利用超薄层等电聚焦酯酮同工酶电泳技术，分析了25个盐溶蛋白不有鉴别双亲与F1的玉米杂交组合，得到了清晰的超薄层等电聚焦酯酶同工酶图谱。共分离出8－16条酶带。其中19个杂交种与亲本间同工酶图谱表现出明显差异。尤其在PI7．0－9．5范围内为互补带，是主要鉴别区，可作为鉴别品种纯度的依据。另外6个杂交组合区别不明显。并讨论了使用超薄层等电聚焦酯酮同工酶电泳技术方法鉴定玉米F1代杂交种品种纯度的优越性。     

杂交稻博优998种子真实性与纯度的IEF鉴定

研究利用等电聚焦技术对博优998及其亲本种子蛋白进行了分析，发现有一条亲本互补谱带。应用该互补谱带，对该杂交稻种子样品进行了鉴定，与田间小区种植鉴定的结果比较差异较小。表明这一技术在杂交稻种子纯度鉴定上是可行的。     

含电压逆变型分布式电源配电网的短路电流计算

分布式发电接入改变了配电网潮流和短路电流分布,其提供的短路电流将对电网保护和重合闸动作产生影响。文中通过研究电压控制逆变型分布式电源（ⅡDG）的故障响应特性,分析配电网不对称故障时ⅡDG三相平均功率与正负序网功率关系,建立计及电压型ⅡDG对称控制特征的短路计算序分量模型。根据ⅡDG与配电网正负序网络的交互作用,推导电压型ⅡDG的故障电流变化规律,提出计算含电压型ⅡDG配电网短路电流的对称分量迭代算法。在PSCAD/EMTDC仿真软件中建立电压型ⅡDG的电磁暂态模型,仿真验证了该方法的正确性。     

大白菜一代杂种及双亲幼苗的等电聚焦电泳过氧化物同工酶分析

等电聚焦电泳是近些年发展起来的分离蛋白质的有效生化技术．操作简便，分辨率高，电泳条带多而且细，信息量大，利于进行深入细致的研究。该文利用等电聚焦丙烯酰胺电泳方法分析了6个大白菜一代杂种及双亲幼苗的过氧化物同工酶电泳图谱，共分离出十几条酶带，F1杂种与亲本间同工酶图谱均表现出明现差异，特别是A鉴别区内的酶带差异最明显，大多为互补型，是主要鉴别区。进一步研究结果表明，6个大白菜品种均可利用过氧化物同工酶鉴别由自交引起的假杂种。利用这项技术大量开展了这6个品种的商品种子纯度检测工作，同时在田间进行了验证性测定，二者结果基本相符。     

改进粒子群算法的自动阻抗匹配技术

由于无线电能传输距离的改变或谐振线圈之间发生偏移、负载改变等多方面的影响使系统的输入阻抗发生变化,导致输入阻抗与射频源内阻不匹配,使传输效率大幅下降。在射频源和发射线圈之间加入阻抗匹配网络可以提高无线电能的传输效率。为了提高阻抗匹配的精度和速度,提出了一种改进的粒子群算法。重点将改进算法和传统算法进行仿真实验比较,证明了改进算法在匹配精度和速度方面的优越性。最后将该算法嵌入到自动阻抗匹配系统中,提高了无线电能的传输效率,同时证明了所提算法的有效性。     

LCL型CPT系统的参数设计方法及频率特性分析

以金鲳鱼为原料,固定小麦粉与水的质量比为2∶1,食盐添加量2%,微波真空度0.095 MPa,在单因素试验的基础上,通过正交试验对微波真空技术膨化鱼糜饼工艺条件进行优化。结果表明,鱼糜饼制作的最佳工艺条件为:鱼糜含量35%,膨化温度100℃,膨化时间20 min,鱼糜饼厚度2 mm,在该工艺条件下,制得的膨化鱼糜饼色泽金黄、质地酥脆、风味清香,成品膨化率可达到540%。     

CALCULATING APPROACH FOR SOLVING LARGE-SCALE POWER SYSTE WITH TOPOLOGY AND PARAMETER GHANGES

A straightforward and unified approach for solving the large-scale, faulted power systems is presented in this paper. In contrast .with conventional algorithms, the various changes of topology and impedance of the systems and its boundary conditions of fault can be handled flexibility and effectively in one-step procedure by proposed method, and it is convenient to choose the computational procedure more resonable according to the situation of power systems. One of the noteworthy features of the proposed method is the natural manner to handle mutual effects, and it is easy to design programs. The calculating technique for easy-to-program is given in this paper. It shows that effectiveness of calculating large-scale faulte power systems with topology and impedance changes by the modified current sources.     

Calculation of lumped parameter of two-port network forvolume conduction energy transfer

Skin electrode unit is a channel through which energy can be transferred to the implanted device by volume conduction. The unit can be equivalent to lumped circuit, but so far there are no appropriate calculation methods of these circuit parameters, so variable load method based on field-circuit coupled is proposed. A skin electrode unit field circuit coupled model is established to obtain the relationship of the network parameters between voltage and current at electrode port, and the amplitude and phase of the power signal is extracted by the use of all phase FFT spectrum analysis. On this basis, equivalent circuit impedance parameters of the skin electrode unit under various conditions are obtained by the application of variable load method and the validity of the method is verified. As a result, the equivalent circuit impedance parameters obtained in this way can be used for the circuit analysis and optimization of the volume conduction energy transfer system.     

A HIERARCHICAL CONTROL METHOD FOR REACTIVE POWER OPTIMIZATION IN LARGE-SCALED INTERCONNECTED POWER SYSTEMS

This paper presents a new hierarchical and coordinative control method for reactive power optimization in large-scale interconnected power systems. It combines the interconnection forecast method for hierarchical control in large-scale steady state industrial systems with the incremental linear programming method for reactive power optimization in real time. The results of applying the method to power system examples show that the method not only solves the problem of high dimension in order, but also keeps the advantages of the incremental linear programming method. The proposed method is also suitable for the security analysis of reactive power correction in large-scale interconnected power systems.     

Distributed Power Flow Method Based on Ward Equivalent

With interconnecting and developing of power system, the problem of power flow computation on dispersed data resource need to be solved. A new distributed computation method of power flow based on Ward equivalent is presented. According to master-slaver splitting principle, multi-area interconnected power system is divided into master-slaver areas. Boundary buses in different areas are defined as different bus-types. Neighborhood areas are equivalent by Ward equivalent principle, and the equivalent injection power and equivalent impedance are worked out. Power flows from master area to slaver areas are solved by Newton method, and the equivalent injection power and equivalent impedance on the boundary are modified by their solutions. The process above repeats until to convergence. The proposed distributed power flow method takes full advantage of the information of power, voltage, network configuration in neighborhood areas, so it is better on convergence and quality of solution. The proposed algorithm is testified by IEEE 14-bus system and a practical 181-bus system.     

A dual-boost three-phase DC link active power filter based on coupled impedance

A three-phase DC link active power filter (APF)based on coupled impedance and its control strategy are proposed in order to eliminate the input current harmonics of the three-phase diode rectifier. The presented APF is composed of impedance network and two asymmetric dual Boost converters. Average current control is adopted to control the DC link APF. The switch signals of the two asymmetric Boost converters are obtained respectively by leading and trailing edge modulation methods. Compared with the normal DC link active power filter,this topology reduces an active switch and a capacitance. So it can reduce costs,and there is no voltage imbalance in the DC link. Simulation results verify the correctness of the proposed topology and the corresponding control method.     

Post-process of Finite Element Method in Electrical Impedance Tomography

In the research of electrical impedance tomography (EIT), each calculation may produce a large amount of data(such as conductance , resistance etc.). The rule of these data is not clear and is hard to understand. How to express the calculation result by means of image in order that such parameters as conductance and resistance can be grasped from the image is significant in analyzing and understanding the calculation result and is helpful to the doctor. This paper has discussed the realization of the post-process of finite element method in electrical impedance tomography and we have developed the software of the post-process of finite element method using Visual C++ .NET and OpenGL. Some problems in drawing the contour line and color contour band have been solved properly.     

Hybrid Intelligent Method for Dynamic Reactive Power Optimization

In dynamic reactive power optimization problem(DRPO), action number constraints of discrete variables should be considered.By integrating immune genetic algorithm(IGA) and nonlinear interior point method(NIPM), a hybrid method for DRPO is proposed.First,the original DRPO problem is converted to a continuous optimization problem by relaxing the discrete variables,and the solution is obtained by NIPM.Then,according to the feature of control variables,the original DRPO problem is decomposed into a continuous optimization sub-problem and a discrete optimization sub-problem.The discrete optimization sub-problem is solved by IGA,and the continuous one is solved by NIPM.By solving the two sub-problems alternately,the optimal solution of the DRPO can be obtained.The proposed hybrid method combines advantages of IGA and NIPM,and finds the approximate optimal solution of DRPO.Numerical simulations on the IEEE 14 bus system illustrate that the proposed hybrid method is effective.     

Limitation and improvement of the equivalent capacity method for calculating the energy loss of distribution networks

Through the analysis of the equivalent resistance method, a limitation of the equivalent capacity method was presented. When the direction of power at the feeder source end was changing, the equivalent capacity method for handling small generations would produce a large power loss calculation error. An improved calculation method, one not based on a single equivalent resistance, was proposed. In this method, one day was divided into several periods (such as 24 h), so that the direction of power at the feeder source end for each period does not vary. The equivalent resistance and energy loss in each period were calculated. The sum of all energy losses provided the daily energy loss total. Numerical examples were used to verify the improved method.