小径材六棱柱体精准成型机的设计

为合理开发利用我国丰富的小径材资源,提高其利用效率,研究设计了小径材六棱柱精准成型机。该成型机主要由工作台、侧面压紧机构、送料机构、切削机构以及床身等部分组成,可用来对小六棱柱体毛坯件进行精准成型加工,得到尺寸精度高、表面质量好的小六棱柱体,为生产大断面六棱柱体集成材提供原材料,满足生产大断面六棱柱体集成材需要。     

南方红壤侵蚀区芒萁散布与坡位的关系——以朱溪小流域为例

以朱溪小流域来油坑野外试验场作为研究区,以实时动态差分仪(Real-time kinematic,RTK)进行微地形实地测量,生成高精度DEM和芒萁分布区,提取研究区微观地形坡位因子,对坡度图和芒萁分布图进行空间叠加,分析坡位对芒萁散布的影响.结果表明,①芒萁散布明显地表现为高度集中于沟谷、低坡和高坡,中坡和平坡地区也少量存在,沟脊不存在或者零星地出现.低坡占41.68％,沟谷30.52％,高坡占17.48％,平坡、中坡和沟脊所占面积最小,均不足5％.②坡位引起水肥变化,导致芒萁在不同坡位上的分布比例不均.③微观地形的研究在实际水土流失区治理中具有重要的意义.     

初创小微企业资金管理绩效影响因素实证研究

依据湖南省229家初创小微企业的调研数据，考量社会资本、政策支持对初创小微企业资金管理绩效的影响。实证表明：社会资本显著影响初创小微企业资金管理绩效；政策支持在社会资本与资金管理绩效中起调节作用，拥有良好政策支持的初创小微企业资金筹集管理绩效与运营管理绩效显著优于缺少政策支持的企业。初创小微型企业应不断丰富自身社会资本，积极利用政府提供的有利环境，提高资金管理绩效。     

EVALUATION OF TWO OBJECTIVE METHODS TO OPTIMIZE KVP AND PERSONNEL EXPOSURE USING A DIGITAL INDIRECT FLAT PANEL DETECTOR AND SIMULATED VETERINARY PATIENTS

It is important to optimize digital radiographic technique settings for small animal imaging in order to maximize image quality while minimizing radiation exposure to personnel. The purpose of this study was to evaluate two objective methods for determining optimal kVp values for an indirect flat panel digital detector. One method considered both image quality and personnel exposure as endpoints and one considered only image quality. Phantoms simulated veterinary patients of varying thicknesses with lesions of varying sizes. Phantoms were exposed to a range of kVp values (60, 81, 100, and 121), using different mAs settings for each phantom. Additionally, all phantoms were exposed to a standard test exposure of 100 kVp/2.5 mAs. Scattered radiation was recorded and used as a measure of personnel exposure. When personnel exposure was considered, a figure of merit was calculated as an endpoint of optimization. The optimal kVp value for each phantom was determined based on the highest signal difference‐to‐noise ratio with or without inclusion of the figure of merit. When personnel exposure was not considered, increasing kVp resulted in higher signal difference‐to‐noise ratios and personnel exposure increased when both patient thickness and kVp increased. Findings indicated that a single standard technique of 100 kVp/2.5 mAs was only optimal for most medium‐sized patients. Images of thinner patients should be made with a lower kVp. Very large patients require a higher kVp than 100 regardless of the optimization method used. Personnel exposure from optimized techniques was low and not expected to exceed annual occupational dose limits.     

中小城镇园林规划常见问题及改进建议

针对当前一些中小城镇园林规划中出现的问题,提出改进措施:立足当地,进行科学系统规划;因地制宜,突出地方特色;注重生态,保护生物多样性;加强全过程监理和后续管理。     

Life‐history differences of juvenile Chinook salmon Oncorhynchus tshawytscha across rearing locations in the Shasta River,California

Salmon from different locations in a watershed can have different life histories. It is often unclear to what extent this variation is a response to the current environmental conditions an individual experiences as opposed to local‐scale genetic adaptation or the environment experienced early in development. We used a mark–recapture transplant experiment in the Shasta River, CA, to test whether life‐history traits of juvenile Chinook salmon Oncorhynchus tshawytscha varied among locations, and whether individuals could adopt a new life history upon encountering new habitat type. The Shasta River, a Klamath River tributary, has two Chinook salmon spawning and juvenile rearing areas, a lower basin canyon (river km 0–12) and upper basin spring complex (river km 40–56), characterised by dramatically different in‐stream habitats. In 2012 and 2013, we created three experimental groups: (i) fish caught, tagged and released in the upper basin; (ii) fish caught at the river mouth (confluence with the Klamath River, river km 0), tagged and released in the upper basin; and (iii) fish caught at the river mouth, tagged and released in the lower basin. Fish released in the upper basin outmigrated later and at a larger size than those released in the lower basin. The traits of fish transplanted to the upper basin were similar to fish originating in the upper basin. Chinook salmon juvenile life‐history traits reflected habitat conditions fish experienced rather than those where they originated, indicating that habitat modification or transportation to new habitats can rapidly alter the life‐history composition of populations.     

Effects of Temperature Changes on the Contractility of Isolated Small Intestinal Smooth Muscle in Rabbits

In order to explore the influence of temperature changes on animal digestive tract smooth muscle,the contractility of isolated rabbit small intestine (duodenum,jejunum and ileum) were measured at different temperatures (39→32℃,32→39℃,39→42℃ and 42→39℃) using the biological signal processing system.The results showed that the contraction frequency of duodenum and jejunum was positively correlated with temperature changes between 39 and 32℃,while the amplitude and tension of duodenum were negatively correlated with temperature changes.Only the contraction frequency of ileum was positively correlated with temperature changes between 39 and 32℃.Changes of frequency,amplitude and tension of duodenum between 39 and 42℃ were similar with those changes between 39 and 32℃.However,the contraction of jejunum and ileum was irregular.When the temperature was decreased from 42 to 39℃,the contraction of small intestine could not return to the condition in 39℃.The results suggested that the optimal bath temperature was 37℃ in contraction test of rabbit small intestine in vitro,and the present results could be referenced to explore the disorder of gastrointestinal movement due to the change of environment temperature in animals.     

彭阳县农业综合开发小流域综合治理成效及对策

分析了彭阳县农业综合开发小流域综合治理存在的问题及取得的成效,总结了其成功的经验,并提出对策,以期为该县农业综合开发小流域综合治理提供参考。     

小断面盾构隧道塌方清理方案

针对小断面盾构隧道直径小、无法采用大型机械设备挖掘清理的实际情况,借鉴盾构机泥水加压平衡模式原理,以某小断面盾构隧道塌方清理为工程背景,探讨了小断面盾构隧道塌方清理技术,制定了用水搅拌淤砂后由泵抽吸至地面泥水分离设备,析出淤砂后的水再返回隧道循环使用的清理方案,包括竖井抽水、隧道排水、隧道上下行段排砂以及设置隧道口安全门等措施.该技术适用于固体颗粒分布不均匀,固相含量较高的清理物,以及环境湿度95％、温度-20～50℃的工况,人工与补水需求量低,对于类似空间受限环境下的清理作业,具有较强的适用性和借鉴性.