形状记忆合金变刚度软作动器设计

软体材料作动器具有良好的目标抓取适应性,为实现软作动器结构的轻量化,保证抓取与承载能力,采用形状记忆合金丝作为驱动元件,设计出一种可变刚度的软作动器。首先,基于形状记忆合金(shape memory alloy,简称SMA)一维本构关系建立了作动器的弯曲变形力学模型;其次,通过实验对力与变形之间的关系进行了验证,弯曲变形与理论结果一致;最后,通过回弹结构的动力学设计,使得该作动器能够在恢复阶段快速回到初始形态。实验结果显示,加热用于变刚度的形状记忆合金丝可显著提升作动器的负载能力,从而达到变刚度的效果。

在线广告竞争面临敏感时刻 微软作梗谷歌难吞DoubleClick

微软咬定谷歌并购的弱点不放,而后者也不可能轻言放弃。Dou- bleClick并不是两强争夺的最后目标,完善自己的广告市场布局。

微软作出战略调整首次推出平板电脑

微软公司6月中旬在洛杉矶发布了自己的平板电脑产品Surface。微软试水平板电脑市场，被认为是增强与苹果等对手竞争的重大战略调整。

螺旋布设光纤光栅的软体操作器形状传感方法

为实现微创手术软体操作器弯曲伸缩运动时的形状测量,提出一种螺旋布设光纤光栅形状传感方法。不同于传统的直线形布设方法,螺旋形布设方法可以防止软体操作器弯曲伸缩运动时,光纤光栅的折断、脱胶现象发生。理论分析了螺旋布设光纤光栅的传感原理及弯曲变形的重构算法;制备了光纤光栅沿螺旋形布设在软体操作器表面的试样;搭建了软体操作器弯曲变形的实验系统;实验分析了软体操作器在不同弯曲状态下,螺旋布设光纤光栅中心波长漂移量与弯曲角度间的变化规律,并重构出软体操作器的变形形状。实验结果表明:螺旋布设光纤光栅在软体操作器中不同位置的灵敏度最大为7.1pm/(°),软体操作器弯曲角度实际测量值与理论重构值间的最大误差不足4.29%。螺旋形光纤传感方法可用于软体操作器形状传感与重构。

螺旋型光纤传感软体操作臂状态测量及特性分析

微创手术软体操作臂是微创外科和机器人领域的科学前沿和研究热点,对提升微创手术水平至关重要。现有视觉、电子和光电等传感方法尚未解决软体操作臂的状态测量问题,以直线型布设在软体操作臂中的光纤传感器,在柔性操作臂伸展和弯曲等运动时存在易断裂和可重复性差等问题,未能实现手术操作臂的闭环控制,限制了其手术应用。为此,提出了一种基于螺旋型光纤传感的软体操作臂状态测量方法,并对其传感特性进行了研究。不同于直线布设光纤的传感方法,螺旋型布设光纤的传感方法可以实现可伸缩软体操作臂的测量,防止光纤在软体操作臂中的错位,满足可伸缩弯曲软体操作臂的测量需求。通过理论分析气动驱动软体操作臂伸缩和弯曲的运动特性,利用光纤上刻写的布拉格光栅传感点,建立软体操作臂中螺旋型光纤光栅的传感模型,推导出光纤光栅中心波长漂移量和软体操作臂弯曲曲率之间的关系。最后,为了验证螺旋型光纤光栅在软体操作臂中的传感性能,对其传感灵敏度和稳定性等进行了实验测试。实验结果表明:提出的螺旋型光纤传感方法可实现操作臂伸长10%、弯曲角度达到180°时的状态测量,且操作臂理论弯曲角度和光纤传感的误差最大为9%,传感灵敏度可达12.55 pm/(°),满足软体操作臂伸缩和各向弯曲操作时的测量需求。

发挥文化软作用 提高安全执行力——“优秀企业安全文化建设策划”介绍

要改变人的不安全行为，最有效的手段是安全文化建设。中国安科院理论与法规标准研究所研究的“优秀企业安全文化建设策划”项目，为企业建设安全文化、提高安全执行力，提供了一个好的途径。

软体操作器结构设计及植入式光纤传感方法

为解决微创手术软体机器人的形状实时监测问题,将刻有三个光纤布拉格光栅的单根光纤植入软体操作器中,利用其研究柔性硅胶软体操作器光纤传感和三维形状重构方法。进行了软体操作器的结构设计及模型建立,并对光纤光栅波长漂移量和软体操作器弯曲曲率之间的关系进行了理论分析;通过实验验证了软体操作器结构设计及其模型建立的有效性,测试了软体操作器不同弯曲状态下三个FBG传感器的反射谱特征及其变化规律;通过分析三个FBG传感器的中心波长漂移量,利用线性插值算法计算出软体操作器在不同弯曲状态下的曲率等参数,并结合曲线拟合方法实现软体操作器的三维形状重构。实验结果表明:植入式光纤光栅传感方法可以实现硅胶软体手术操作器的三维形状传感,在微创外科手术领域具有广阔的应用前景。

聚氨酯合成革柔软工艺的研究

在试验的基础上,论述了制造柔软、舒适手感合成革的主要工艺措施,指出了PUR树脂的选择和机械作软是其最主要的工艺控制。

自传感介电弹性体执行器的动力学设计及应用

本文提出了一种传感与作动一体化的介电弹性体(DE)软执行器,可用于薄膜结构形面变形的同步测量和控制.首先,建立DE软执行器电致驱动过程的动力学模型,描述其力电耦合行为.其次,通过开展动态作动实验,辨识该动力学模型的参数.第三,分析不同参数对作动器动态响应的影响,以理解其基本动力学特性.第四,建立DE软执行器自传感过程的简化电路模型,并对其电学参数与位移之间的关系进行实验标定.最后,开展平面薄膜结构的形面位移自适应调整实验,并设计相应的控制策略.实验结果表明,该DE软执行器在作动和传感方面均具有较高精度.因此,其在构建高精度空间薄膜天线方面具有较好的应用前景.

ZERO-CURRENT AND ZERO-VOLTAGE SWITCHING PWM BOOST FULL-BRIDGE CON VERTER

This paper proposes a zer o current and zero voltage switching (ZCZVS) PWM Boost full bridge (FB) conve rter. With series inductors, the leading switches can realize zero current swit ching (ZCS) in a wide load range using the energy of the output capacitor. Ma king use of parasitic capacitors of the lagging switches and parallel auxiliary i nductance with the primary winding of the transformer, the lagging switches can realize zero voltage switching (ZVS) under any load. Compared with the ZCS PWM Boost FB converter, the new converter has no current duty cycle loss. Operat ional principle and parameter design are analyzed. Experimental results verify the effectiveness of the proposed converter.

绳驱动软体操作臂的建模与控制技术研究

研究了一款绳驱动软体操作臂的建模与控制技术。基于分段恒曲率模型,研究了驱动空间与关节空间之间、关节空间与任务空间之间的映射和逆映射关系。使用MATLAB软件进行了软体操作臂的工作空间分析和运动性能仿真。根据运动学原理,搭建实验样机平台,通过伺服电机控制驱动绳的长度。在样机平台上进行了软体操作臂的运动控制实验,结果显示分段恒曲率模型不足以准确地控制软体操作臂。在单变量条件下和多变量条件下,分别使用曲线拟合和BP神经网络的方法,对软体操作臂的运动进行了补偿控制。

Antagonistical Mode of Pichia membranefaciens to Rhizopus stolonifer in Wounds of Peach Fruit

膜醭毕赤酵母 (PichiamembranefaciensHansen)是本实验室从果实上分离获得的一种能有效防治桃果实采后软腐病的拮抗菌。本文将P .membranefaciens与葡枝根霉 (Rhizopusstolonifer)在桃果实伤口部位共培养 2 4h后 ,用扫描电子显微镜观测了它们的拮抗作用。结果表明 ,在有病原菌的地方聚集了大量的酵母拮抗菌 ,而且拮抗菌紧密地吸附在病原菌的菌丝体上。结合以前的研究结果可以推断 ,P .membranefaciens主要通过与病原菌进行营养和空间的竞争 ,紧密地吸附在病原菌菌丝体上分泌能降解病原菌细胞壁的水解酶 (如几丁质酶和 β_1,3_葡聚糖酶 ) ,并可能诱导寄主产生抗性 ,从而抑制桃软腐病的发生。

Flow behaviour constitutive model of CuCrZr alloy and 35CrMo steel based on dynamic recrystallization softening effect under elevated temperature

In order to study the effect of dynamic recrystallization on the metal flow behavior during thermal deformation,the elevated temperature compression experiments of CuCrZr alloy and 35CrMo steel are carried out using Gleeble-3810 thermal simulator.It is proved that the samples underwent obvious dynamic recrystallization behavior during thermal deformation by microstructure observation of deformed specimens.The size of recrystallized grains increases as the temperature improved and the strain rate decreased.Meanwhile,the net softening rate caused by dynamic recrystallization is determined based on the stress-dislocation relationship.It can be found that the value of net softening rate increases quadratically as the Z parameter decreases,and the dynamic recrystallization net softening rate of CuCrZr alloy and 35CrMo steel are calculated to be 21.9%and 29.8%,respectively.Based on the dynamic recrystallization softening effect proposed,the novel elevated temperature flow constitutive models of two different alloys are proposed,and the related parameters are well defined and solved in detail.The predicted values of the obtained models are agreed well with the experimental values.

Simulation on dissolute and dust dispersion in comprehensive mechanized heading face with forced-exhaust ventilation

According to the characteristics of comprehensive mechanized heading face, established the mathematical model of single-phase air flow with κ-ε two equations model, and have established κ-ε-θ-κp mathematic model to solve two-phase flow of gas and particles in dust space with eulerian-eulerian method and eulerian-lagrangian method. Numerical solution of gas-particle two-phase flow was put forward based on collocated grid SIMPLE algorithm. Moreover, numerical simulation of dust concentration in fully mechanized caving face was carded out by using Fluent software. Finally, when in forced-exhaust ventilation circumstance, drawer type fan drum have less dust absorption, and most of dust spread to the other site; the dust concentration is inversely proportional to the distance from tunneling head, and the dust concentration has already diffused to decrease below 102 mg/m3 at the position ofx=12 m. Dust are more focused on relative side（in the range about y from 0 to 2 meter） of roadway space of press-ventilated fan drum, especially between tunneling place and drawer type fan drum; the roadway with road header have a higher dust concentration. These conclusions provide reliable theory basis for the dust prevention in comprehensive mechanized heading face.

Study on “triangle” water-inrush mode of strong water-guide collapse column

The water-inrush mechanism of strong water-guide collapse column in coal seam is studied based on the establishment of geological and mathematical models of "triangle" water-inrush mode. The geological background of Shuangliu mine is considered a prototype, similar simulation tests are adopted to analyze the water-inrush rules under this model, and the formation of water-guide channel and water-inrush process is investigated by examining the changes in rock resistivity. This work also uses the coupled cloud image derived from numerical simulation software to verify the results of simulation test. Results show that the numerical simulation of "triangle" water-inrush mode is consistent with the similar simulation. The "triangle" seepage area, which is located at the bottom of collapse columns and is connected to aquifer, is caused by the altered seepage direction and strengthened seepage actions after the overlapping of hydraulic transverse seepage in collapse column and hydraulic vertical seepage flow in aquifer. Under "triangle"water-inrush model, water-guide channel is formed by the communication between plastic failure zone of working face baseplate and"triangular" seepage area. Accordingly, the threatening water-inrush distance between working face and collapse column increases by 20 m compared with that of theoretical calculation.

Effect of Dissolved Organic Matter on Chlorotoluron Sorption and Desorption in Soils

A batch equilibrium techniques was used to examine the effect of dissolved organic matter （DOM） extracted from both non-treated sludge （NTS） and heat-expanded sludge （HES） on the sorption and desorption of chlorotoluron （3-（3-chloro-p-tolyl）-1,1-dimethylurea） in two types of soils, a yellow fluvo-aquic and a red soil from China. Without DOM,sorption of chlorotoluron was significantly greater （P 〈 0.05） in the red soil than in the yellow fluvo-aquic soil. However,with DOM the effect was dependent on the soil type and nature of DOM. Chlorotoluron sorption was lower in the yellow fluvo-aquic soil than in the red soil, suggesting that with the same DOM levels the yellow fluvo-aquic soil had a lower sorption capacity for this herbicide. Application of DOM from both NTS and HES led to a general decrease in sorption to the soils and an increase in desorption from the soils. Desorption of chlorotoluron also significantly increased （P 〈 0.05） with an increase in the DOM concentration. Additionally, for sorption and desorption, at each DOM treatment level the NTS treatments were significantly lower （P 〈 0.05） than the HES treatments. This implied that non-treated sludge had a greater effect on the sorption and desorption of chlorotoluron than heat-expanded sludge.

A Corpus-Based Analysis of the Animal Images in The Wind Among the Reeds

The Wind Among the Reeds, written from 1889 to 1939, is regarded as one of the most remarkable poetry collections of William Butler Yeats. It altogether includes 80 poems touching upon several themes such as love, religion, dignity, and life. Yeats is one of the most distinguished Irish poets throughout the world, whose works perfectly embody the incorporation of romanticism, modernism, and occultism. It is noteworthy that in some of his poems, animals are portrayed frequently or even taken as the title of a poem, such as bird, fish, swan and so on. Therefore, this essay attempts to study the meaning of animal images of this poetry anthology in terms of different writing phases of Yeats. Firstly, the author builds the corpus of The Wind Among the Reeds and employs corpus search software Ant Cone to check the number and distribution of the animal image. Next, the author focuses on certain prominent images and investigates them further by analyzing the concordance lines of them. Thirdly, according to the result of distribution information, the author also attaches importance to the phenomenon of image combination in the poetry and then explores its function and effect. To conclude, by exploring the animal image in The WindAmong the Reeds, a deeper understanding of the poetry and the writing style of the poet will be gained on another level. What is more, a more direct and objective data is provided through the method of corpus and its relevant software, thereupon a new research approach is introduced.