水平连续铸钢凝固过程数值模拟     

刘金水  蒋冰 《湖南农业大学学报(自然科学版)》1995,22(3)

本文在分析水平连铸传热特征的基础上，给出了一维情况下，计算结晶器出口处铸坯凝固层厚度的解析式，建立了计及轴向传热的连续坯凝固模拟模型。进行了连续坯二维传热的凝固数值模拟，其模拟结果与实验结果吻合较好，具有普遍应用价值。  相似文献   

Surgical treatment of a complicated distal tibia epiphyseal Salter–Harris type I fracture in a yearling     

A. C. Noguera Cender  C. J. Lischer  K. Mählmann 《Equine Veterinary Education》2021,33(5):e155-e160

This article describes the management of a complicated distal epiphyseal Salter–Harris type I fracture of the left tibia in a yearling horse. Closed reduction and internal fixation was attempted in the first surgery using tension band wires. Due to fracture instability 2 weeks after surgery, a full-limb transfixation pin cast was applied to the tibia and maintained for 7 weeks to prevent further fracture displacement and to achieve axial alignment. The full-limb cast was maintained for a total of 12 weeks, including the time with the transfixation pin cast. Cast sores and tendon laxity resolved without further complications. Ten months after the first surgery, the fracture had radiographically healed, and the horse was sound at the walk and trot in a straight line.  相似文献   

Ultrastructural impairment of islet microvascular endothelial cells in STZ-induced type 1 diabetic mice     

ZHANG Xu  LIU Ming-ming  CHENG Ming  XU Jin  WANG Shu-he  WANG Hui  REN Ya-li  XIU Rui-juan  WANG Su-xia 《园艺学报》2015,31(8):1520

AIM: To investigate the ultrastructural changes of islet microvascular endothelial cells in STZ-induced type 1 diabetic mice. METHODS: BALB/c mice were randomly divided into diabetic group and control group. The expression of insulin and platelet-endothelial cell adhesion molecule-1 (CD31) in islet microvessels was detected by immunohistochemical staining. The ultrastructural changes of islet β cells and islet microvessels were observed under transmission electron microscope. RESULTS: Compared with control group, the number of islet β cells, ratio of β cells/α cells, average number of secretory granules in β cells and insulin expression area per islet in diabetic group were significantly decreased (P<0.01). Besides, diabetic group had fewer microvessels with lower expression of CD31 (P<0.01). Mitochondria in islet microvascular endothelial cells and pericytes in diabetic group were swelling. The basement membrane of islet microvessels became thicker in diabetic group (P<0.01). CONCLUSION: Islet microvascular endothelial cells were impaired in type 1 diabetic mice.  相似文献   

白口铸铁机械性能研究及在农机制造中的应用(I)     

刘锷  肖于德  邱立春 《农机化研究》2007,(6)

为了提高白口铸铁的冲击韧性等机械性能,扩大其在农机具上的应用范围,采用BZ变质剂对白口铸铁进行变质浇铸,并研究了变质剂对白口铸铁中碳化物的断网效果。试验结果表明,变质剂对于含碳量在3.2%以下、含铬量在12%以下的白口铸铁具有较好的断网效果。  相似文献   

农业机械铸铁基件裂纹的修复技术     

苏炳玲  宋金虎 《农业装备与车辆工程》2007,(12):60-63

通过对焊修方法的选取和工艺的分析，提出解决农业机械铸铁基件的修复方法。  相似文献   

Research Advances in Escherichia coli K1 Penetration Across Blood-brain Barrier     

LING Chen  ZHANG Qi-wen  SONG Kang  JIANG Jian-jun  YAN Gen-qiang 《中国畜牧兽医》2017,44(3):686-691

E.coli K1 strain is a representative strain of neonatal sepsis and meningitis, which causes disease by blood circulation to the brain. The molecular mechanism of E.coli K1 that adhering and invading the brain microvascular endothelial cells (BMECs) and cross the blood brain barrier (BBB) has been focused on by many scholars. In this review, we focused on the gene regulation mechanisms and signaling pathway of E.coli K1 crossing the blood brain barrier to understand the molecular mechanism of the infection caused by E.coli and provide reference for prevention and treatment programs.  相似文献   

等温淬火球墨铸铁的热处理及应用   总被引：1，自引：0，他引：1  

李佐锋 《农业装备与车辆工程》2007,(6):11-13

探索了等温淬火球墨铸铁的生产工艺,分析了原料化学成分的选择,及铸造工艺中的熔炼、球化和孕育处理、浇注温度对制取球墨铸铁的影响;在获得基体组织合理的球墨铸铁的前提下,重点分析了热处理工艺中的奥氏体化温度、等温淬火温度和时间对ADI组织及性能的影响,通过实验及分析,确定了制取理想ADI的最佳热处理工艺。  相似文献   

烟后稻抛栽育秧技术研究与应用     

官贵德 《福建稻麦科技》2014,(2):1-4

通过不同的软盘、育秧方式、播种密度、施氮量、化控次数等烟后稻抛栽育秧试验和多年试验示范结果,提出"选盘、旱育、稀播、适氮、化控"等烟后稻抛栽育秧关键技术。通过生产验证表明,应用该育秧关键技术,不仅能解决烟后种植中迟熟超级稻品种抛栽出现长秧龄、育壮秧难、产量不高等问题,还能有效提高烟后茬超级稻产量水平。  相似文献   

灰口铸铁电弧热焊法补焊工艺的研究     

王泽荫  马云  李宗义 《湖南农机》2014,(8)

文章分析了灰口铸铁的焊接性和常用的焊接方法,阐述了电弧热焊法对灰口铸铁进行补焊时的焊接工艺。  相似文献   

免耕抛栽水稻源库特性研究   总被引：3，自引：0，他引：3  

韦善清  徐世宏  李如平  郎宁  江立庚  董登峰  张平刚  陈念平  秦华东  陆福勇 《中国农学通报》2005,21(9):237-241

近些年来,水稻免耕抛秧栽培在中国广西等部分地区发展迅速。为了探讨免耕抛栽水稻产量形成特点,以金优253(OryzasativaL.)为试验材料,以常耕抛栽水稻为对照,从叶面积大小、剑叶光合速率与衰老、库的大小及源库比率等方面研究了免耕抛栽水稻的源库特性。结果表明,免耕抛栽水稻早、晚季产量分别为5.97t/hm2和7.53t/hm2,常耕抛栽水稻分别为6.19t/hm2和7.63t/hm2,其产量差异在早季和晚季均不显著。与常耕抛栽水稻相比,免耕抛栽水稻的每穗总粒数和单位面积上的总粒数较多,各生育期的叶面积指数较大,灌浆期剑叶光合速率、蒸腾速率、气孔导度、叶绿素含量较高,而过氧化物酶和过氧化氢酶活性及丙二醛的含量较低,在生理上存在一定的优势。但是,免耕抛栽水稻的源库协调能力较差,粒叶比和结实率下降,致使免耕抛栽水稻在产量上表现出一定的劣势。免耕抛栽水稻粒叶比和结实率的下降是由于其生产的干物质更多地分配在叶片中、贮藏在茎鞘中的干物质在抽穗后向穗部运转的能力较差造成的。  相似文献