金属热防护系统多层隔热材料的传热分析及参数优化     

闫长海  曲寿江  孟松鹤  陈贵清  杜善义  刘国仟 《勤云标准版测试》2006,(4):257-263

采用能量平衡方程和离散坐标法近似地建立了金属热防护系统多层隔热材料的一维稳态传热的数学模型，并利用遗传算法和纤维隔热材料的有效导热系数试验数据求解传热反问题，从而得到了模型中的纤维隔热材料的辐射衰减系数、反照率和隔热屏表面辐射发射系数。最后，由实验测得了多层隔热材料的有效导热系数，验证了采用优化参数后，多层隔热材料的传热模型的正确性。  相似文献   

不同钠浓度对白三叶草和多年生黑麦草生长的影响     

彭克勤  胡笃敬 《湖南农业大学学报(自然科学版)》1993,(2)

白三叶草对Na 的反应比多年生黑麦草敏感.培养液中的Na 浓度从0.1mmol/L 增至0.5mmol/L 时,其干物质生产下降37%;增至2.5mmol/L 时,干重下降49%,而多年生黑麦草的干重仅降低6%.2种牧草的Na 含量均随培养液Na 浓度的增加而提高,K 含量未受影响.白三叶草的Na 含量低于多年生黑麦草,而K 含量高于多年生黑麦草.试验结果暗示,白三叶草对K 的选择吸收能力较多年生黑麦草强,但耐盐能力较差,生态适应性不如多年生黑麦草广.  相似文献   

某些阳离子在大豆胞囊线虫生防系统中的作用   总被引：2，自引：0，他引：2  

邢丽娟  陈大力  刘维志  段玉玺 《中国生物防治》2002,18(1):1-5

室内测定了不同浓度的 6种阳离子 :钼、硼、锌、铜、锰和铁对大豆胞囊线虫卵的孵化、大豆种子发芽和根系生长 ,以及对线虫生防菌———厚垣轮枝菌菌丝生长的影响。结果发现 ,在供试所有浓度下 ,铜、锰和铁明显抑制大豆胞囊线虫的卵孵化 ,锌具明显刺激作用 ;在供试浓度水平较低时 ,铜、锰和铁对大豆种子发芽及根系生长有轻微抑制 ,锰的抑制较为明显 ,但均不影响进一步发育 ;在供试浓度较低时 ,铜、锰和铁对厚垣轮枝菌菌丝生长无任何影响。铜可作为线虫生防制剂的添加剂。  相似文献   

Removal of a metallic foreign body from the tongue of three horses     

M. Blatter  M. Thunig  F. Kretschmar  A. B. M. Rijkenhuizen 《Equine Veterinary Education》2021,33(4):e97-e103

The objective of this case report is to describe the diagnostic and surgical techniques for removal of a metallic foreign body in the tongue of three adult horses. The three horses were presented for evaluation and treatment of dysphagia and marked hypersalivation of 3–5 days duration. Radiographs of the head revealed the presence of a metallic foreign body in the tongue of each horse. The foreign bodies could be precisely localised under general anaesthesia using palpation and lingual ultrasonography and/or lingual radiography in combination with a forceps as a marker. The foreign bodies were successfully removed using laparoscopic instruments creating minimal soft tissue trauma. The use of long (43 cm) small laparoscopic (5 mm) instruments enabled good visualisation of the surgical field, providing optimal conditions for successful minimally invasive surgical treatment of horses with foreign bodies in the tongue. The three horses made uneventful recoveries and 12 months after surgery were eating normally and could be ridden with a bit as per usual routine. It was concluded that using long laparoscopic instruments in combination with palpation, ultrasonography and/or radiography allowed removal of the foreign body creating minimal soft tissue trauma and allowing optimal conditions for a fast recovery.  相似文献   

Hydrolysis and Condensation of Silane Agent for Metallic Surface Treatment   总被引：1，自引：0，他引：1  

XU Yi  TANG Shou yuan  TENG Yi  ZHANG Xiao feng 《保鲜与加工》2002,(10):72-74

Novel surface treatment technique by silane film is developing for metallic anti corrosion and coat improvement. The key points, hydrolysis and condensation, for the stability of the Silane agent(SA) solution is investigated, and the effective factors of stability for silane agent solution and the relative rule are discussed. It is found that stability of SA solution is related to the temperature, pH, solvents, SA concentration and additive by studying the state of the solution and the conductivity-time curve of SA solution. Meanwhile, controlling factors and improving methods for SA stability are proposed to guide the practical application of metallic surface anti-corrosion treatment by SA.  相似文献   

A New Method for Parameterized Design of Metallic Doors and Windows     

SONG Yu chuan  YAN Chun ping  LIU Fei  LIU Wan qi 《保鲜与加工》2001,(4):36-39

According to the graphics characteristics of metallic doors & windows design and based on the research of graphics dimension restriction problems. This paper provides a new method for parameterized design of metallic doors & windows in virtue of expression solution. In this method, the restrictions of graphic elements have been changed into the parameter expressions of sizes and positions of graphic elements. Through the calculation of such expressions, the parameter driven method has been reached. Thus the parameterization of graphics can be easier and quicker than before. It can be used to setup the open parameterized graphics libraries.  相似文献   

水化学分析方法在水电工程勘探中   总被引：2，自引：0，他引：2  

韩冬梅  梁杏  张晓伦 《中国农村水利水电》2004,(12):110-113

水电工程有限的勘察及水文地质钻探仅能获取少量水文地质信息，而在工程勘察特别是平硐中，易取得出水点的水样，通过水化学分析可以获得更多的水文地质资料。通过对四川省自一里水电站平硐出水点水化学样的系列采集和测试，运用水化学成分离子比例分析法、灰色关联分析法和D、18O同位素分析等多种方法提取了平硐区水文地质信息，分析了山区平硐裂隙水的来源、补给高度及岩层渗透性等水文地质特征，探讨了水化学分析方法在分析水电工程水文地质条件中的应用。  相似文献   

Diagnosis and Management of Nasopharyngeal Stenosis     

《Veterinary Clinics of North America: Small Animal Practice》2016,46(4):677-689

  相似文献   

云栖竹径公园空气负离子生态效益评价     

黄旸钧  秦登  张协腾  方莉  蒋文伟 《中国园艺文摘》2013,(6):70-71

以杭州市云栖竹径公园典型植物群落毛竹纯林、常绿阔叶林及毛竹、枫香混交林为研究对象,研究3种不同植物群落空气负离子变化及其与气象因子之间的关系。研究结果表明,不同植物群落空气负离子浓度大小排序为毛竹林>毛竹+枫香混交林>常绿阔叶林,毛竹纯林具有更加强的环境气候调节效应,在改善城市气候方面发挥着重要的作用。  相似文献   

Selenium desorption from Ca‐Kaolinite     

《Communications in Soil Science and Plant Analysis》2012,43(7):771-779

Abstract

Toxic selenium (Se) concentrations were found recently in shallow groundwater in the west side of the San Joaquin Valley in California. The objective of the present work was to evaluate whether excessive leaching, variations in pH, and the presence of competing ions may contribute to Se solubilization and accumulation in the drainage water.

Selenium desorption from a Ca‐Kaolinite suspension deviated considerably from the corresponding adsorption isotherm. Raising the suspension pH from 5.6 to 8.7 resulted in the release of all the Se present in the system into the solution phase. Decreasing the pH from 5.6 to 3.6, reduced Se and Se concentrations in the solution by a factor of 3 and 2, respectively. When adding P at a 10:1 P‐to‐total Se molar ratio, Se and Se concentrations in the solution increased from 1.5 to 2.3 and from 2.4 to 2.6 pM, respectivley. Sulfate ions at the same, or higher, molar ratios had no apparent effect on Se solubilization.  相似文献