两轮自平衡机器人

针对于现在流行的两轮自平衡车,设计了一个与其原理相似的研究性两轮自平衡机器人系统。该系统以瑞萨RL78/G13单片机为主控制器,通过MPU6050陀螺仪采集加速度和角速度数据,采用软件滤波和四元素融合算法得到机器人姿态,最后利用PID控制算法计算电机的PWM值以控制电机的合理转动,使机器人保持平衡和运行。     

基于CAN协议的多电机控制

根据CAN总线的技术规范,编制CAN总线高层通信协议,实现对电机群的协同控制。该电机群控制系统以STM32ARM为运动控制器,以四个电机为控制对象,各电机控制模块之间通过CAN总线实现通信。以两个电机为控制对像的模拟测试结果表明,编制的CAN总线的高层通信协议简单可靠,且系统的同步性和稳定性都较好。     

基于CAN协议的多电机控制

根据CAN总线的技术规范,编制CAN总线高层通信协议,实现对电机群的协同控制。该电机群控制系统以STM32ARM为运动控制器,以四个电机为控制对象,各电机控制模块之间通过CAN总线实现通信。以两个电机为控制对像的模拟测试结果表明,编制的CAN总线的高层通信协议简单可靠,且系统的同步性和稳定性都较好。     

基于GUI/Simulink的起落架收放控制逻辑联合建模与仿真研究

以某型飞机起落架收放控制系统收放控制逻辑为对象,建立Matlab GUI(graphic user interface)和Simulink联合仿真模型,与单独采用Simulink建模相比,联合仿真模型具有显示直观、便于测试分析等优点。仿真结果表明,联合仿真模型能够实现不同测试方案的快速测试、仿真结果对比分析及记录,能够完成起落架收放控制逻辑的全数字仿真需求,为起落架收放控制逻辑的验证分析提供有力的支持。     

山西·吉县试验成功半自动果园防雹网

正本刊讯日前,吉县壶口建筑公司第四分公司研制的屋脊型半自动果园防雹网试验成功。屋脊型半自动果园防雹网采用屋脊型结构,利用屋脊型两侧斜面,减少阳光照射量,同时能够有效卸载冰雹,减少了防雹网承重压力,延长防雹网使用寿命。防雹网通过联动定滑轮组、紧缆机、钢缆等一系列机械结构,使整个防雹网的收放仅两人即可操作完成,且收放速度快,操作方便,有效节省了防雹网的收放时间和成本。     

基于STM32的两轮自平衡遥控小车设计

两轮自平衡小车作为一种新型的交通工具,其驾驶的方式新颖,深受年轻一族喜爱,且由于是采用的电力驱动,属于清洁能源,对于缓解日益严重的大气污染、能源危机和交通拥堵问题,是一种比较好的解决方式,同时由于两轮自平衡小车的结构不稳定性,给控制的算法提出了很大的挑战,同时由于这个原因平衡车也成为了一种检验控制算法的良好平台。本平衡车使用STM32单片机作为控制核心,通过电机编码器与陀螺仪实时获得小车速度与姿态数据,运用PID控制算法使得小车能够保持平衡。     

探讨刮板输送链运动特性的改善方法

<正> 目前,粮食和饲料加工厂中所用的刮板输送机多采用电动机一摆线针轮减速器一套筒滚子链传动的动力传动系统,如图1。电动机与摆线针轮减速器直联。链传动分别与摆线针轮减速器及刮板输送机相连.两个链轮分别装在摆线针轮减速器的输出轴及刮板输送     

养蛋鸡在未来一年有钱可赚

<正>眼下,鸡蛋价格终于走出困境,养殖户们也终于可以舒一口气了。这一轮涨价能到怎样一个价位?能维待多长时间?笔者个人认为,直到明年10月底,养鸡户们都有望处在赢利期。鸡蛋价格高低关键取决于供求关系。去年10月份以来,鸡蛋价格经历了两次成本线以下的低潮,第一次是今年     

圆、方坯抛丸机抛头电机变频改造

圆、方坯抛丸机是利用抛丸工艺清除圆钢、方钢等件表面氧化皮和钢材因轧制而形成的表面鳞层。抛丸机的4台主抛头电机原来采用接触器星三角启动控制模式,在生产实践过程中接触器以及电机损坏频繁故障率较高,更换电机比较费时费力,导致维修工作量很大增加了维护成本。现改用变频器替代原来的接触器控制模式后,故障率减小,运行效率提高,电耗降低。     

基于凸极效应的混合动力车用IPMSM无传感器控制的设计

本文提出了一个集中绕组式IPMSM的设计。该设计基于凸极特性的无传感器控制,采用高频信号注入法。充分考虑到交叉耦合磁饱和和空间谐波,利用有限元理论检测无传感器驱动的可行域。可靠性通过使用两个原型来予以验证。然后,验证IPM电机结构对可行域的影响。最后,建立设计指导以获得合适的电机结构。所提出的设计的有效性通过基于MATLAB/SIMULINK的动态仿真器进行验证。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

Evaluation of serum concentrations of biomarkers of skeletal metabolism and results of radiography as indicators of severity of osteochondrosis in foals

OBJECTIVE: To determine whether serum concentrations of biomarkers of skeletal metabolism can, in conjunction with radiographic evaluation, indicate severity of osteochondrosis in developing horses. ANIMALS: 43 Dutch Warmblood foals with varying severity of osteochondrosis. PROCEDURE: 24 foals were monitored for 5 months and 19 foals were monitored for 11 months. Monthly radiographs of femoropatellar-femorotibial and tibio-tarsal joints were graded for osteochondral abnormalities. Serial blood samples were assayed for 8 cartilage and bone biomarkers. At the end of the monitoring period, foals were examined for macroscopic osteochondrosis lesions. RESULTS: Temporal relationships were evident between certain serum biomarkers and osteochondrosis severity in foals during their first year. Biomarkers of collagen degradation (collagenase-generated neoepitopes of type-II collagen fragments, type-I and -II collagen fragments [COL2-3/4C(short)], and cross-linked telopeptide fragments of type-I collagen) and bone mineralization (osteocalcin) were positive indicators of osteochondrosis severity at 5 months of age. In foals with lesions at 11 months of age, osteochondrosis severity correlated negatively with COL2-3/4C(short) and osteocalcin and positively with C-propeptide of type-II procollagen (CPII), a collagen synthesis marker. Radiographic grading of osteochondrosis lesions significantly correlated with macroscopic osteochondrosis severity score at both ages and was strongest when combined with osteocalcin at 5 months and CPII at 11 months. CONCLUSIONS AND CLINICAL RELEVANCE: The ability of serum biomarkers to indicate osteochondrosis severity appears to depend on stage of disease and is strengthened with radiography. In older foals with more permanent lesions, osteochondrosis severity is significantly related to biomarker concentrations of decreased bone formation and increased cartilage synthesis.