新型涡轮叶片冷却技术换热特性实验研究

通过实验研究了一种新型涡轮叶片冷却技术（Thermal driving in high centrifugal field，TDHCF）的换热特性。该技术主要利用高彻体力场下微小封闭循环通道内流体的热驱动运动来达到高效换热的目的。实验中分别采用了液态H2O和氟利昂R12为热驱动介质，分析了离心力场下热驱动运动的流动规律和换热特性，讨论了TDHCF技术的总平均换热效果KH随旋转速度和热流密度的变化规律。研究发现：离心力场下，采用不同的流体作为热驱动介质所形成的热驱动运动规律相同，温度分布也基本类似，均是随着转速和热流密度的增加，热驱动运动强度提高，平均换热系数随之变大。研究结果表明：旋转速度、热流密度以及热驱动介质的热物性均影响了TDHCF所最终能达到的换热效果，其中旋转速度的影响尤为显著；在热流密度或转速不变的情况下，以液态氟利昂R12为热驱动介质，TDHCF可以达到更高的强化换热效果。与常规的气冷技术相比，采用TDHCF可以有效地提高换热效果。     

A形排架杆件内力简化计算法

提出了一种计算A形排架杆件轴力的通用公式，应用此公式可避免求解各结点的静力平衡方程组，直接计算任意杆件的轴力．     

多功能脚踏式机具的驱动机构设计

就我省山区和丘陵地区广大农村在农业生产和部分农产品加工所需的人力多功能机具的驱动机构从理论方面进行了分析，并对该机构的基本形式和最佳工况以及曲柄的最佳位置进行了分析，提出了驱动机构的设计基本要求，推出了驱动机构各构件的设计计算公式，为人力多功能机具设计打下了理论基础。     

Investigation of the immediate analgesic effects of extracorporeal shock wave therapy for treatment of navicular disease in horses

OBJECTIVES: To measure the acute analgesic properties of extracorporeal shock wave therapy (ESWT) in horses with navicular disease using objective ground reaction forces (GRF). STUDY DESIGN: Prospective study. ANIMALS: Nine client-owned horses with unilateral forelimb lameness caused by navicular disease. METHODS: Horses were trotted at 3 m/s over a force plate to record pre-treatment GRF of the lame and contra-lateral forelimbs. After ESWT of the lame limb, applied with a radial unit to each of the frog and heel bulb areas with 1500 pulses at 4 bar and 10 Hz, GRF measurements were repeated at 15 minutes and 24-hour intervals for 7 days. From the 5 trials recorded at each time, peak vertical force (PVF) was calculated and averaged. Data were compared between limbs and over time using a 2-way repeated-measures ANOVA. RESULTS: Mean (+/-SD) PVF was significantly different between lame (day 1; 4339+/-626 N) and contra-lateral (day 1; 5236+/-515 N) limbs pre-treatment (P<.05). After ESWT treatment, this difference remained unchanged at 15 minutes and from days 1 to 7. To confirm navicular disease, palmar digital analgesia significantly reduced the lameness (lame 5144+/-430 N; contralateral 5082+/-586 N; P>.05). CONCLUSIONS: Single ESWT treatment applied in this manner does not influence lameness in horses with navicular disease. CLINICAL RELEVANCE: Although many equine regulatory commissions currently ban the use of ESWT before competition, our results suggest that such regulations may be unfounded. Further research is required to determine the long-term analgesic properties of this frequently used treatment modality in equine athletes.     

Accuracy and optimization of force platform gait analysis in Labradors with cranial cruciate disease evaluated at a walking gait

OBJECTIVE: To determine the combination of ground reaction forces (GRFs) that best discriminates between lame and non-lame dogs. To compare the sensitivity of force platform gait analysis and visual observation at detecting gait abnormalities in Labradors after surgery for rupture of the cranial cruciate ligament (CCL). ANIMALS: All dogs were adult Labrador Retrievers: 17 free of orthopedic and neurologic abnormalities, 100 with unilateral CCL rupture, and 131 studied 6 months after surgery for unilateral CCL injury, 15 with observable lameness. PROCEDURE: Dogs were walked over a force platform with GRF recorded during the stance phase. Analytic properties of force platform gait analysis were calculated for several combinations of forces. The probability of visual observation detecting a gait abnormality was compared with that of force platform gait analysis. RESULTS: We determined that a combination of peak vertical force (PVF) and falling slope were optimal for discriminating sound and lame Labradors. After surgery, many dogs (75%) with no observable lameness failed to achieve GRFs consistent with sound Labradors. CONCLUSION: A force platform is an accurate method of assessing lameness in Labradors with CCL rupture and is more sensitive than visual observation. Assessing lameness with a combination of GRFs is better than using univariate GRFs. CLINICAL RELEVANCE: Therapies for stifle lameness can be accurately and objectively evaluated using 2 vertical ground reaction forces obtained from a force platform.     

Force plate analysis before and after dorsal decompression for treatment of degenerative lumbosacral stenosis in dogs

OBJECTIVE: Using force plate analysis (FPA), determine ground reaction forces in dogs with degenerative lumbosacral stenosis (DLS) and evaluate the effects of lumbosacral decompressive surgery. STUDY DESIGN: Prospective clinical study. ANIMALS: Twelve dogs with DLS. METHODS: DLS was diagnosed by clinical signs, radiography, computed tomography, and/or magnetic resonance imaging. FPA was performed before surgery, and 3 days, 6 weeks, and 6 months after surgery. The mean peak braking (Fy+), peak propulsive (Fy-), and peak vertical (Fz+) forces of 8 consecutive strides were determined. The ratio between the total Fy- of the pelvic limbs and the total Fy- of the thoracic limbs (P/TFy-), reflecting the distribution of Fy-, was analyzed to evaluate any changes in locomotion pattern postoperatively. Ground reaction force data for DLS dogs were compared with data derived from 24 healthy dogs (control). RESULTS: In dogs with DLS, the propulsive forces (Fy-) of the pelvic limbs were significantly smaller than those of controls. P/TFy- was significantly smaller in dogs with DLS than in control dogs, and increased during the follow-up period, reaching normal values 6 months after surgery. CONCLUSIONS: Cauda equina compression in dogs with DLS decreases the propulsive force of the pelvic limbs and surgical treatment restores the propulsive force of the pelvic limbs in a 6-month period. CLINICAL RELEVANCE: In dogs with DLS, FPA is an effective method in evaluating the response to surgical treatment. Normal propulsive force in the pelvic limbs was restored during 6 months after decompressive surgery.     

重庆市巴南区农村居民点用地变化的驱动机制

为揭示农村居民点用地变化驱动机制,为政府决策提供科学依据,以西南丘陵地区为研究对象,利用Logistic回归模型和多元线性回归模型对巴南区农户居民点用地变化进行了相关分析。结果表明:显著影响农户"是否新辟地基建房"的因素包括:"风水"心理、自然灾害、宅基地来源和交通条件;显著影响农户"新辟地基建房占地面积"的因素包括:家庭常住人口数量、宅基地来源、农村税费改革、农村宅基地政策法规的认知。对两者影响最显著的都为宅基地来源因素。由此可见,荒地或闲置用地为新辟地基建房的主要用地来源,且相对其他用地来源建房占地面积较大。因此,在保护耕地不被占用的同时,政府应控制荒地或闲置用地建房超占现象,从而保护潜在的耕地来源。     

耕地变化与人文驱动因素分析——以会宁县为例

对会宁县耕地变化与人文驱动因素进行了研究,结果表明:2000～2009年会宁县耕地面积变化表现波动性中的下降,上升—平稳—下降—平稳特征显著。但在各个乡镇的表现态势不一致,利用ArcGis生成耕地相对变化率空间分布图,发现变化率在0.59～0.75的区域是耕地面积减少最为明显的区域,主要有会师镇;变化率在1.40～1.56的区域是耕地面积增加最为明显的区域,变化除了一部分自然和政策的因素外,主要受人口和经济增长影响。     

基于PERCLOS的疲劳驾驶检测系统的实现

本文阐述了PERCLOS测评驾驶疲劳的机理.介绍了疲劳识别的算法,该系统首先利用肤色模型粗略检测出人脸区域,并根据驾驶员面部几何特征,准确定位出眼睛;然后根据眼睛区域白色像素的多少及闭眼持续时间对驾驶员状态做出判断;最后应用Microsoft Visual C++6.0在Windows XP操作平台上,对疲劳检测判定进行实现.实验表明:该系统可以准确定位眼睛并判定驾驶员疲劳状态,其准确率为94.44％.     

公路建设项目生态损益驱动研究

生态损益驱动过程是生态补偿价值核算和定价研究的基础,明确生态损益过程寻找驱动来源并度量其生态影响,确定驱动源与生态影响变化关系,可为生态补偿主客体划分和价值核算提供理论和计算依据.从公路建设行为的岩土过程、景观过程及运营过程3个方面从时间和空间角度,系统分析建设期、运营期的公路建设行为影响源及生态影响,构建生态损益驱动特征的量化分析方法与模型及其公路建设项目生态损益的驱动网络,可为公路建设项目生态补偿定价及价值核算研究提供理论支撑.