在DH或RIL群体中两对重叠基因控制性状的定位

在DH或RIL群体中,若只找到与两对重叠基因控制性状连锁的1个分子标记,可采用极大似然法估计控制性状的一对基因与分子标记间的重组率,并推导出重组率估计值的标准误公式。MonteCarlo模拟显示,重组率估计值的无偏性较好,其变异随时样本容量或重组率的增加而减少。

“基因对性状的控制”一课的论证式教学设计

通过设置问题情境引导学生判断主张、寻找事实与证据、科学推理及探究学习,论证主张“基因决定生物性状”的正确性,采用小组合作学习尝试建构“中心法则”模型,训练科学思维,形成生命观念,提升生物学核心素养。

控制数量性状的基因对数及作用的估计

对ｎ个位点等作用、等频率的同类基因控制性状的基因位点数和基因作用进行了研究，推导出了具有上述条件的父母代群随机交配后，其后代的表型值及其出现频率、群体均数、群体方差、选择亲本群基因频率、选择亲本群均数通式及在运用任三代可测参数中，推导了基因对数与基因作用的关系方程式，并提供了估算同类基因控制性状的基因对数公式和估算基因作用的方法。

基于“理性思维”的初中生物学探究活动教学策略——以《基因控制生物的性状》一课为例

理性思维是生物学科的核心素养之一。本论文以《基因控制生物的性状》一课为例,在尊重事实和证据的基础上,利用归纳与概括、演绎与推理、批判性思维等方法,在学生活动设计中发展学生的理性思维。

植物病害流行学(一)

前言植病流行学是植物病理学中的一门新兴学科。从本世纪60年代起,现代科学技术进入相互渗透、迅速发展的新时期。在植物病理学中,Flor 在研究亚麻锈菌致病性的基础上,在50年代中期提出了基因对基因的假说,被认为是植物病理学历史中的重要事件之一。1963年,Vanderplank

“中心法则”教学抬遗

“中心法制”是遗传学上有关遗传信息流向一个概念,是教材中关于基因对性状控制一节的中心内容。旧版教材对其只简单地定义为:“由DNA—→RNA—→蛋白质的遗传信息传递过程。”新版(1985)教材则在此基础上,补充了“遗传信息从DNA 传遗给(?)NA 的复制过程”这一重要内容,使“中心法则”概念进一步完善。为了检查学生对“中心法则”

“目录”在复习课中的作用

“目录”是全书的总蓝图,每一个章节的标题都是相关内容的概括。生物课本“目录”的编排充分地反映了该门课程内容的相互联系,科学地体现了知识的相关性、连续性,不论从编排的次序上或从编排的密度上讲,都能再现出编者的主导思想及内容的主、次。科学地、完整地理解“目录”的章节层次。

Fuzzy robust sliding mode control of a class of uncertain systems

Aiming at a class of systems under parameter perturbations and unknown external disturbances, a method of fuzzy robust sliding mode control was proposed. Firstly, an integral sliding mode surface containing state feedback item was designed based on robust H∞ control theory. The robust state feedback control was utilized to substitute for the equivalent control of the traditional sliding mode control. Thus the robustness of systems sliding mode motion was improved even the initial states were unknown. Furthermore, when the upper bound of disturbance was unknown, the switching control logic was difficult to design, and the drawbacks of chattering in sliding mode control should also be considered simultaneously. To solve the above-mentioned problems, the fuzzy nonlinear method was applied to approximate the switching control term. Based on the Lyapunov stability theory, the parameter adaptive law which could guarantee the system stability was devised. The proposed control strategy could reduce the system chattering effectively. And the control input would not switch sharply, which improved the practicality of the sliding mode controller. Finally, simulation was conducted on system with parameter perturbations and unknown external disturbances. The result shows that the proposed method could enhance the approaching motion performance effectively. The chattering phenomenon is weakened, and the system possesses stronger robustness against parameter perturbations and external disturbances.

Morphology Control of Anatase TiO2 by Surfactant-assisted Hydrothermal Method

By hydrolysing titanium isopropoxide in a long hydrocarbon chain surfactant-containing solution, TiO2 fine particles with a diversity of well-defined morphologies was synthesized in this study by a hydrothermal route. The structural change during the formation process was monitored by scanning electron microscopy, transmission electron microscopy and X-ray diffraction analysis. TiO2 with various morphologies such as particle, sheet, rod, tube and flower-like shape was obtained by carefully controlling the preparation conditions. The experimental results show that the pH value is crucial for shape control of the produced TiO2 because it can change the charge state of the surfactant in the solution and the adsorption potential of the surfactant on the TiO2 surface. The shape evolvement of anatase TiO2 was elucidated by quenching the reaction at different stage and the formation mechanism of different shaped TiO2 was suggested.

Robust stabilization and disturbance attenuation for a class of underactuated mechanical systems

The robust control problem for a class of underactuated mechanical systems called acrobots is addressed. The goal is to drive the acrobots away from the straight-down position and balance them at the straight-up unstable equilibrium position in the presence of parametric uncertainties and external disturbance. First, in the swing-up area, it is shown that the time derivative of energy is independent of the parameter uncertainties, but exogenous disturbance may destroy the characteristic of increase in mechanical energy. So, a swing-up controller with compensator is designed to suppress the influence of the disturbance. Then, in the attractive area, the control problem is formulated into a H~ control framework by introducing a proper error signal, and a sufficient condition of the existence of Hoo state feedback control law based on linear matrix inequality （LMI） is proposed to guarantee the quadratic stability of the control system. Finally, the simulation results show that the proposed control approach can simultaneously handle a maximum ±10% parameter perturbation and a big disturbance simultaneously.

Achieving Consistence for Cross-Domain WAN Control in Software-Defined Networks

When applying Software-Defined Networks(SDN) to WANs,the SDN flexibility enables the cross-domain control to achieve a better control scalability.However,the control consistence is required by all the cross-domain services,to ensure the data plane configured in consensus for different domains.Such consistence process is complicated by potential failure and errors of WANs.In this paper,we propose a consistence layer to actively and passively snapshot the cross-domain control states,to reduce the complexities of service realizations.We implement the layer and evaluate performance in the PlanetLab testbed for the WAN emulation.The testbed conditions are extremely enlarged comparing to the real network.The results show its scalability,reliability and responsiveness in dealing with the control dynamics.In the normalized results,the active and passive snapshots are executed with the mean times of 1.873 s and 105 ms in135 controllers,indicating its readiness to be used in the real network.

Retraction control of motorized seat belt system with linear state observer

A design and verification of linear state observers which estimate state information such as angular velocity and load torque for retraction control of the motorized seat belt (MSB) system were described. The motorized seat belt system provides functions to protect passengers and improve passenger's convenience. Each MSB function has its own required belt tension which is determined by the function's purpose. To realize the MSB functions, state information, such as seat belt winding velocity and seat belt tension are required. Using a linear state observer, the state information for MSB operations can be estimated without sensors. To design the linear state observer, the motorized seat belt system is analyzed and represented as a state space model which contains load torque as an augmented state. Based on the state space model, a linear state observer was designed and verified by experiments. Also, the retraction control of the MSB algorithm using linear state observer was designed and verified on the test bench. With the designed retraction control algorithm using the linear state observer, it is possible to realize various types of MSB functions.

Multi-domain modeling and simulation of proportional solenoid valve

A multi-domain nonlinear dynamic model of a proportional solenoid valve was presented.The electro-magnetic,mechanical and fluid subsystems of the valve were investigated,including their interactions.Governing equations of the valve were derived in the form of nonlinear state equations.By comparing the simulated and measured data,the simulation model is validated with a deviation less than 15%,which can be used for the structural design and control algorithm optimization of proportional solenoid valves.

Research on improved active disturbance rejection control of continuous rotary motor electro-hydraulic servo system

In order to meet the precision requirements and tracking performance of the continuous rotary motor electro-hydraulic servo system under unknown strong non-linear and uncertain strong disturbance factors,such as dynamic uncertainty and parameter perturbation,an improved active disturbance rejection control(ADRC)strategy was proposed.The state space model of the fifth order closed-loop system was established based on the principle of valve-controlled hydraulic motor.Then the three parts of ADRC were improved by parameter perturbation and external disturbance;the fast tracking differentiator was introduced into linear and non-linear combinations;the nonlinear state error feedback was proposed using synovial control;the extended state observer was determined by nonlinear compensation.In addition,the grey wolf algorithm was used to set the parameters of the three parts.The simulation and experimental results show that the improved ADRC can realize the system frequency 12 Hz when the tracking accuracy and response speed meet the requirements of double ten indexes,which lay foundation for the motor application.

The effect of acute exercise on cognitive performance in children with and without ADHD

Background： Attention deficit hyperactivity disorder （ADHD） is a common childhood disorder that affects approximately 11% of children in the United States. Research supports that a single session of exercise benefits cognitive performance by children, and a limited number of studies have demonstrated that these effects can also be realized by children with ADHD. The purpose of this study was to examine the effect of acute exercise on cognitive performance by children with and without ADHD. Methods： Children with and without ADHD were asked to perform cognitive tasks on 2 days following treatment conditions that were assigned in a random, counterbalanced order. The treatment conditions consisted of a 30-min control condition on 1 day and a moderate intensity exercise condition on the other day. Results： Exercise significantly benefited performance on all three conditions of the Stroop Task, but did not significantly affect performance on the Tower of London or the Trail Making Test. Conclusion： children with and without ADHD realize benefits in speed of processing and inhibitory control in response to a session of acute exercise, but do not experience benefits in planning or set shifting.

Nonlinear state estimation for fermentation process using cubature Kalman filter to incorporate delayed measurements

State estimation of biological process variables directly influences the performance of on-line monitoring and op- timal control for fermentation process. A novel nonlinear state estimation method for fermentation process is proposed using cubature Kalman filter （CKF） to incorporate delayed measurements. The square-root version of CI（F （SCKF） algorithm is given and the system with delayed measurements is described. On this basis, the sample-state augmentation method for the SCKF algorithm is provided and the implementation of the proposed algorithm is constructed. Then a nonlinear state space model for fermentation process is established and the SCKF algorithm incorporating delayed measurements based on fermentation process model is presented to implement the nonlinear state estimation. Finally, the proposed nonlinear state estimation methodology is applied to the state estimation for penicillin and industrial yeast fermentation processes. The simulation results show that the on-fine state estimation for fermentation process can be achieved by the proposed method with higher esti- mation accuracy and better stability.

Design of variable structure controller for uncertain time-delay singular system

To study the approximation theory of real sliding mode and the design of variable structure controller for time-invariant linear uncertain time-delay singular system,the approximation theory of real sliding mode was developed to provide foundation for obtaining sliding mode by equivalent control,and switching functions with integral dynamic compensators and variable structure controllers were designed respectively under two circumstances that the system without uncertain part was stabilized by delay-dependent and delay-independent linear state feedback. The design guarantees the asymptotical stablity of switching manifolds,and the variable structure controllers can force solution trajectory of the system to arrive at the switching manifolds in limited time. A numerical example is given to demonstrate the feasibility and simplicity of the design method.

Stabilization of a class of nonlinear discrete time systems with time varying delay

The stability and stabilization of a class of nonlinear discrete time delayed systems(NDTDS) with time-varying delay and norm-bounded nonlinearity are investigated. Based on discrete time Lyapunov–Krasovskii functional method, a sufficient delaydependent condition for asymptotic stability of nonlinear systems is offered. Then, this condition is used to design a new efficient delayed state feedback controller(DSFC) for stabilization of such systems. These conditions are in the linear matrix inequality(LMI) framework. Illustrative examples confirm the improvement of the proposed approach over the similar cases. Furthermore, the obtained stability and stabilization conditions will be extended to uncertain discrete time delayed systems(UDTDS) with polytopic parameter uncertainties and also with norm-bounded parameter uncertainties.