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51.
沙漠用仿驼蹄橡胶轮胎的设计与试验研究   总被引:9,自引:6,他引:3  
研制沙漠轮胎是开发沙漠车辆的关键技术之一。根据仿生学原理,建立仿驼蹄轮胎原理模型并首次研制了仿驼蹄轮胎橡胶模型。进行仿驼蹄橡胶轮胎的参数设计,并在室内沙槽模拟台对仿驼蹄轮胎橡胶模型进行了试验研究。研究结果表明,仿驼蹄轮胎橡胶模型具有较高的沙地通过性。  相似文献   
52.
Computed tomography (CT) was performed on 12 Finnhorse cadaver forefeet with known radiographic changes in the navicular bone (poor corticomedullary junction, irregular appearance of the flexor central eminence, uneven or unequal thickness of the flexor cortex, and/or irregular outline of the proximal or distal flexor margin). The purpose was to confirm the radiographic findings and to investigate if further information of the flexor aspect of the bone could be gained with CT. In CT, the midsagittal outline as well as the internal structure of the bones varied greatly. Different combinations of trabecular and compact bone were seen within the flexor central eminence. Lucencies within the compact bone were commonly present in the proximal half of the eminence, but in five bones lucencies were also identified in the distal half. Due to partial overlapping of the bone and varying bony composition of the eminence, accurate radiographic evaluation of the shape and internal structure of the flexor central eminence was often found to be difficult. The flexor cortex usually appeared to be thinner in CT than in conventional radiographs. Medullary sclerosis and poor flexor corticomedullary junction were commonly overinterpreted radiographically. New bone formation on the proximal flexor margin of the navicular bone was generally visualized in radiographs, but CT allowed also the evaluation of the internal structure of the bone. In one navicular bone, an avulsion fragment on the distal flexor margin was seen in CT images; radiographically this fragment could not be visualized. It was concluded that the flexor aspect of the navicular bone may be difficult to assess reliably with conventional radiography.  相似文献   
53.
羊腐蹄病主要是导致蹄部发生化脓、溃疡,出现跛行,呈现出发病率较高,感染性很快的特点。本文主要以一起羊腐蹄病的诊断与治疗为重点进行报告,较为详细地介绍了综合防治措施,旨在引导广大养殖者借鉴参考,做好该病的防治工作,减少养殖经济损失。  相似文献   
54.
用猪抗口蹄疫病毒IgG制备荧光抗体,检测口蹄疫病毒感染BHK-21细胞中的病毒抗原,结果表明,该方法可以检出口蹄疫病毒感染BHK-21细胞中的病毒抗原,荧光抗体的工作浓度确定为1:40,且这种荧光能被FMDV阳性血清特异性地抑制。用制备的荧光抗体检测感染口蹄疫病毒CS株和LB株的BHK~21细胞抹片和飞片,结果均为阳性,空白对照均为阴性。对于低代次的分离毒,即使感染细胞产生明显的CPE,采用反向间接血凝试验也不能检出收获细胞液中的病毒抗原,本试验弥补了这一缺陷。采用直接荧光抗体法可确定病毒在感染细胞中增殖的位置,可作为兽医临床诊断方法之一。  相似文献   
55.
裸岩石砾地客土土体结构对水肥渗漏的影响   总被引:4,自引:0,他引:4  
针对裸岩石砾地利用客土法整治后新增耕地存在失水失肥的现象,以秦岭北麓某荒石滩新增耕地客土耕层作为模拟研究对象,将供试土壤以不同容重分层填装试验土柱,并对其进行了水分入渗试验,分析了裸岩石砾地人为耕作层结构的水分、养分渗漏特征。通过对5种耕作层结构的模拟渗漏试验,结果表明:(1)人为耕层土壤初始渗漏能力和渗漏速率与模拟心土层容重呈负相关关系,其入渗过程可用修正后的Kostiakov入渗模型进行模拟;(2)心土层土壤容重对累积入渗量、入渗速率及养分流失量均有较大影响,并呈负相关关系;(3)分析养分总渗漏量显示,存在一个最优耕层结构,在此耕层结构具有较好的保肥效果。通过综合分析水肥渗漏状况,确定最优耕层结构自下而上容重分别为1.5,1.3,1.2g/cm3。  相似文献   
56.
目的 研究中医体质类型与糖尿病足溃疡(diabetic foot ulcers,DFU)的相关性,为糖尿病足溃疡的防治提供新思路。方法 随机收集住院2型糖尿病足溃疡患者73例,采用标准化的中医体质量表判定患者体质类型,并进行身高、体质量、血糖、血脂等指标的测量和观察记录伤口愈合速率、愈合时间、预后结局等情况。分析中医体质对2型糖尿病足溃疡伤口愈合的影响。结果 DFU患者以痰湿质、血瘀质和湿热质为多。其中血瘀质相对其他两种体质足溃疡程度较重,湿热质感染程度较重。湿热质的年龄最低,血瘀质相对年龄偏大。痰湿质的身体质量指数(BMI)最大,糖尿病病程最短(P<0.05)。血瘀质伤口愈合速率和时间较慢(P<0.05)。结论 痰湿质、血瘀质和湿热质是2型糖尿病足溃疡的高危体质,不同DFU患者临床特征不同,血瘀质的伤口愈合较慢,提示不同体质下DFU的预防及治疗应有侧重。  相似文献   
57.
针对地下水资源可持续利用与表生生态协调发展的问题,在对天山北麓野外调查及已有研究结果分析的基础上得出细土平原区生态水位埋深为3~6 m。应用数值模拟技术对现状及调整开采布局后地下水位引起的表生生态效应进行对比,结果表明:现状地下水资源开发布局不仅易诱发表生生态负效应,而且造成了水资源浪费;通过调控地下水状态可以实现地下水资源可持续利用与表生生态协调发展的目的,并确定了不同地貌单元地下水开采阈值即山前戈壁带、细土平原区和沙漠边缘分别为7.3亿m3/a,16.4亿m3/a和2.4亿m3/a。  相似文献   
58.
腐蹄病(foot rot)是侵害反刍动物趾间皮肤及深层软组织为主的,严重影响奶牛生产性能和产奶质量的一种常见疾病。由于传统的灭活菌苗具有免疫效果差、副反应严重及大量生产困难等缺点,使腐蹄病基因工程疫苗的研究成为热点。笔者对坏死杆菌白细胞毒素作为腐蹄病亚单位疫苗候选抗原研究的最新进展进行综述,希望为腐蹄病亚单位疫苗的研究提供参考。  相似文献   
59.
Reasons for performing study: Lameness associated with lesions of the deep digital flexor tendon (DDFT) in the digit is now recognised as an important cause of lameness, but there is currently limited information about the pathological nature of the lesions. Objectives: To compare: signal intensity changes on magnetic resonance images with histopathology; and histopathological changes in the DDFT from horses with no history of foot‐related lameness (Group C) and horses with lesions of the DDFT confirmed using magnetic resonance imaging (MRI) (Group D). Methods: Transverse sections of the DDFT were harvested from 3 sites in all horses: 1) immediately proximal to the navicular bursa (E1); 2) at the level of the navicular bone (E2); and 3) close to the tendon's insertion (E3). If lesions were identified at E1 or had been identified further proximally using MRI, additional sections were obtained until, in most cases, the proximal limit of the lesion was identified. All DDFTs were graded histopathologically using predefined criteria. The MR images were reviewed to determine the location and sequences in which increased signal intensity was seen. Results: No haemorrhage or inflammatory cell infiltration was seen in any horse. At level E 1 , septal thickening, ghosting of blood vessels and blood vessel occlusion were common in Group D, but were not seen in Group C. Less commonly, there was core necrosis, only seen in Group D. At level E 2 , septal and vascular changes were most obvious in Group D. Core necrosis, dorsal splitting, crevicing and fibrillation were seen only in Group D. Septal and vascular changes were present in both Groups C and D at level E 3 , but fibrocartilaginous metaplasia, splitting, crevicing and fibrillation, or core necrosis or fibroplasia were seen only in Group D. Core lesions in Group D often extended proximal to E 1 , and ranged in length from 0.5–13 cm. Core necrosis was generally associated with increased signal intensity in fat suppressed images. Conclusions: Lesions of the DDFT in the digit appear to be primarily degenerative, and may be a sequel to vascular compromise. Increased signal intensity on fat suppressed MR images is not necessarily associated with frank fluid or evidence of inflammation, but may reflect major matrix changes in the tendon. Potential relevance: Further information about the causes of these lesions is required to develop preventative strategies.  相似文献   
60.
将70头30日龄仔猪随机分成7组,每组10头,在口蹄疫免疫过程中按1%添加剂量使用中草药复方制剂,Ⅰ、Ⅱ、Ⅲ组分别在免疫前5天、3天、当天开始连续饲喂3天,Ⅳ、Ⅴ、Ⅵ组分别在免疫前5天、3天、当天饲喂1天。对照组(Ⅶ组)不喂药。分别于免疫前一天和免疫后14d、21d、28d和二免后28d,采血检测NK细胞数量。结果表明:投药组NK细胞数量均高于对照组,Ⅰ、Ⅱ、Ⅲ组NK细胞数量高于Ⅳ、Ⅴ、Ⅵ组,Ⅱ组NK细胞数量最高,其中Ⅰ、Ⅱ、Ⅲ组与对照组差异显著(P<0.05),Ⅳ、Ⅴ、Ⅵ组与对照组差异不显著(P>0.05)。  相似文献   
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