船舶压载水系统仿真及稳性调节

为满足船员的适任性训练要求,文中开发了船舶压载水模拟训练系统,以某4万吨油轮为母型船,以M in is通用仿真支撑系统和InTouch组态软件作为软件开发平台,开发了船舶压载水系统的仿真和监控软件。介绍了该系统的总体结构、工作过程及仿真功能,并详细叙述了运用该软件进行油轮稳性调节的具体过程。仿真结果显示:本系统符合评估规则的要求,可以成为轮机模拟器压载水部分的仿真软件。

浅论银屑病中辅助性T细胞17/调节性T细胞稳态与阴阳的关系

在银屑病的发病机制中存在着一套辅助性T细胞17/调节性T细胞稳态系统,它在银屑病等自身免疫性疾病发病机制中有着重要地位,且与中医“阴阳”平衡高度相似。根据阴阳定义,辅助性T细胞17细胞相关物质与免疫炎症激动、促进炎症相关,属“阳”,调节性T细胞相关物质与免疫抑制、炎症抑制相关,属“阴”。中医对银屑病的认识不断的变化,但治病求本,辨别阴阳,寻求理法方药,使人体恢复阴阳协调的状态是亘古不变的目标。综合银屑病的病因、皮损情况与内部症状、证型分布和用药规律,银屑病在阴阳辨证中多属热证、阳证,少有纯阴证,较多为半阴半阳证。治疗前后辅助性T细胞17/调节性T细胞稳态的变化理论上支持了辅助性T细胞17相关物质为“阳”,调节性T细胞相关物质为“阴”的假设。但缺乏相关证据支持辅助性T细胞17/调节性T细胞稳态与半阴半阳证的联系。

双吊联动吊装超长重大件货方案设计

为降低双吊联动吊装超长重大件货的作业风险,根据吊装作业时船舶稳性变化,将整个吊装方案分为货物转动路径规划和船舶稳性调节两个阶段进行设计。采用调拨左右舷压载水的方法调节船舶稳性,通过确定货物的无碰撞转动路径和各步骤所需调拨压载水量设计最终的吊装方案。以实船数据验证了该吊装方案设计方法的可行性。

大型绿色装配建筑暖通空调系统节能技术优化

传统装配建筑暖通空调系统节能方法忽略了对供风端电压波动的抑制,导致空调系统输出稳定性较差,节能效果不明显。为解决该问题,提出新的基于模糊PID控制的大型绿色装配建筑暖通空调系统节能控制方法。以空调换流机的输出稳态特征量为控制对象,构建装配建筑暖通空调节能控制约束参数模型。结合热电机组气动功率以及电磁功率的PID模糊约束方法,实现对暖通空调系统节能输出稳态性调节。建立空调系统供风端电压波动的模糊PID控制模型,结合气动功率的小扰动抑制方法,实现对大型绿色装配建筑暖通空调系统节能优化控制。实验结果表明,所提暖通空调系统节能控制方法的输出稳定性较好,与传统方法相比,所提方法下空调系统电压增益更大,且功耗一直低于20kWh,在实验测试过程中,所提方法的平均能量开销少于传统方法,以上实验结果验证了所提方法具有更好的应用性能。

Design of an optimal active stabilizer mechanism for enhancing vehicle rolling resistance

Improving rollover and stability of the vehicles is the indispensable part of automotive research to prevent vehicle rollover and crashes.The main objective of this work is to develop active control mechanism based on fuzzy logic controller(FLC) and linear quadratic regulator(LQR) for improving vehicle path following,roll and handling performances simultaneously.3-DOF vehicle model including yaw rate,lateral velocity(lateral dynamic) and roll angle(roll dynamic) were developed.The controller produces optimal moment to increase stability and roll margin of vehicle by receiving the steering angle as an input and vehicle variables as a feedback signal.The effectiveness of proposed controller and vehicle model were evaluated during fishhook and single lane-change maneuvers.Simulation results demonstrate that in both cases(FLC and LQR controllers) by reducing roll angle,lateral acceleration and side slip angles remain under 0.6g and 4° during maneuver,which ensures vehicle stability and handling properties.Finally,the sensitivity and robustness analysis of developed controller for varying longitudinal speeds were investigated.

Infiltration regulation and stability analysis of soil slope under sustained and small intensity rainfall

Rainfall infiltration depth and mode can severely influence slope stability.With the sustained rainfall,the influenced region of slope gradually expands.By using the Green-Ampt model to the soil slope,infiltration regulation was discussed under sustained and small intensity rainfall.And the infiltration rate of unsaturated soil was proposed according to the saturated infiltration theory.Because of the changing of initial moisture content in depth of slope,the saturated or unsaturated infiltration rate and depth could also be changeable with the sustained rainfall infiltration.Based on the principle of strength reduction,the calculation model of slope safety factor was established under different initial moisture contents and infiltration modes.Then,the slope stability was quantitatively analyzed through software FLAC3D.The calculation results of soil slope engineering show that there is a shorter period for slope stability under different initial moisture contents and unsaturated infiltration ways at the slope wetting front.The stability period of slope is 33.3%according to different initial moisture contents of wetting front less than that of the same initial moisture content of wetting front.And the slope is easier to fail under the unsaturated infiltration.The results agree well with the actual situation under sustained and small intensity rainfall.

Using a Computer Driven PID Regulator for Controlling the Vacuum Pump of a Mechanical Milking Machine

Conventional vacuum control in a milking system is accomplished by using a vacuum pump, sized for the maximum air flows into the milking system, running at a full speed. The difference between the pump capacity and the necessary flow of air is compensated by allowing air to enter the system through a regulator. The solution presented in this paper uses a VFD （variable frequency driver） in order to drive the vacuum pump at a controlled speed, so that the air removed equals the air entering the milking system. The VFD technology is able to adjust the rate of air removal from the milking system, by changing the speed of the vacuum pump motor. The VFD is controlled by a computer using a virtual instrument in order to emulate a PID （proportion integration differentiation） regulator. The tests aimed to evaluate the vacuum regulator characteristics and vacuum stability. A statistical analysis of the experimental results was performed and it showed that there was a significant difference between the experimental results obtained for the two methods of vacuum regulation （with vacuum regulator and VFD controller respectively）. The experimental results proved that the used of the VFD controller led to a higher vacuum stability in terms of the error between the set vacuum value and the achieved values.

Impaired function of the suprachiasmatic nucleus rescues the loss of body temperature homeostasis caused by time-restricted feeding

The suprachiasmatic nucleus(SCN)is the master circadian pacemaker that drives body temperature rhythm.Time-restricted feeding(TRF)has potential as a preventative or therapeutic approach against many diseases.The potential side effects of TRF remain unknown.Here we show that daily 4-h TRF treatment in mice can severely impair body temperature homeostasis and can result in lethality.Nearly half of the mice died at 21℃,and all mice died at 18℃during 4-h TRF.This effect was modulated by the circadian clock and was associated with severe hypothermia due to loss of body temperature homeostasis.Remarkably,disrupting the circadian clock by SCN lesions or constant light rescued lethality during TRF.Analysis of circadian gene expression in the dorsomedial hypothalamus(DMH)demonstrated that TRF reprograms rhythmic transcriptome in DMH and suppresses expression of genes,such as Ccr5 and Calcrl,which are involved in thermoregulation.Together,our results demonstrated a potent effect of TRF on body temperature homeostasis and the role of SCN function in this process.Our results further suggested that circadian arrhythmicity can have potential beneficial effects under certain stress conditions.

Active steering control strategy for articulated vehicles

To improve maneuverability and stability of articulated vehicles, we design an active steering controller, including tractor and trailer controllers, based on linear quadratic regulator(LQR) theory. First, a three-degree-of-freedom(3-DOF) model of the tractor-trailer with steered trailer axles is built. The simulated annealing particle swarm optimization(SAPSO) algorithm is applied to identify the key parameters of the model under specified vehicle speed and steering wheel angle. Thus, the key parameters of the simplified model can be obtained according to the vehicle conditions using an online look-up table and interpolation. Simulation results show that vehicle parameter outputs of the simplified model and Truck Sim agree well, thus providing the ideal reference yaw rate for the controller. Then the active steering controller of the tractor and trailer based on LQR is designed to follow the desired yaw rate and minimize their side-slip angle of the center of gravity(CG) at the same time. Finally, simulation tests at both low speed and high speed are conducted based on the Truck Sim-Simulink program. The results show significant effects on the active steering controller on improving maneuverability at low speed and lateral stability at high speed for the articulated vehicle. The control strategy is applicable for steering not only along gentle curves but also along sharp curves.