硼对培养大鼠肾细胞和人羊膜细胞内氟含量的影响

通过动物实验和人群观察结果证实,硼进入人体与氟结合形成氟硼酸根随尿排出,减轻氟负荷。通过体外实验,首次发现2．2mmol四硼酸钠在2－3h内可降低6．0mmol氟化钠暴露下的WISH人羊膜细胞和大鼠肾细胞内的氟含量,这可能是硼拮抗氟的细胞毒作用的重要途径之一。根据不同情况下培养细胞内和培养液中氟含量的测定结果,推测硼可直接降低细胞膜对氟离子的通透性,从而减少完整细胞内的氟含量,增加机体的耐氟力,减轻氟毒性。     

GH128铸态合金中硼的分布

采用高分辨率的径迹显微照相技术,研究了GH128铸态合金中硼的偏析和在均匀化、正火、调质热处理过程中硼分布的变化,并且分析了硼含量、加入稀土元素以及合金中Mo等元素对硼分布的影响．硼在铸态合金中有明显的偏析现象,并随着硼含量的增加而偏析加剧,经过常规的均匀化处理之后,铸态合金中硼分布状态受Mo偏析的影响非常显著．在一定的条件下,硼相沿着奥氏体的特定结晶学平面析出,或结晶界形成粗大连续网状的硼相,从而导致沿晶界的脆性断裂,实验表明稀土元素有保护硼的良好作用．     

三氟化硼乙醚溶液催化的内酯化反应:合成4-Aryl-2-phenyl-4,6-dihydrofuro[3,4-c]furan-6-ones

在三氟化硼乙醚溶液催化下 ,羟基酸 (5 Phenylfuran 4 arylcarbinol 3 carboxylicAcids)以较好的收率转化为内酯 (4 Aryl 2 phenyl 4 ,6 dihydrofuro[3,4 c]furan 6 ones) .     

热压微晶碳化硼材料研磨面白斑成因探析

热压微晶碳化硼材料是用于宇航控制系统的材料 ,对其可靠性要求极高 .有些热压微晶碳化硼材料研磨面上有宏观可见的白色斑点 ,这是一种异常现象 .通过对白色区形貌和成分的分析 ,认为白斑是在磨削过程中形成的基体表面剥落 ,剥落区凹凸不平造成反光强度不同 ,因而在宏观上呈现为白色 .白斑区成分是正常的碳化硼相 ,并非夹杂有外来物质 ,并提出了消除这一现象的可能途径     

温度场数值模拟在低铬硼铸球工艺中的应用

利用温度场数值模拟对低铬硼铸球的凝固过程进行了计算·在研究铸球凝固过程温度分布规律的基础上,改进了铸造工艺,消除了缩孔等缺陷·经落球冲击疲劳寿命试验机测定,直径127铸球落球次数>8000次·     

屈服强度800 MPa的低碳微合金钢

研究了不同成分特征的含锰含碳微合金钢通过控轧控冷后回火的组织与力学性能,Mn含量为1．7％－2．3％的试验钢轧后经快冷和中温回火获得了高强度和一定的塑性、韧性,其中含0．06％,2．3％Mn,0．21％Al和微量Nb,Ti,B的快冷回火钢屈服强度（σ0．2）超过800MPa,延伸率大于4％。室温冲击韧性134－174．5J／cm^2,－40℃冲击韧性为103－110J／cm^2,具有由变形奥氏体转变成的细小贝氏体组织。     

Effect of dislocation configuration on non-equilibrium boron segregation during cooling

Different densities and configurations of crystal defects were obtained in an austenitic Fe-30%Ni alloy and an ultra low carbon bainitic (ULCB) alloy by undergoing different deformations and annealing treatments at high temperatures. Boron segregation on grain boundaries and subgrain boundaries during air-cooling were revealed by means of the particle tracking autoradiography technique. It is found that non-equilibrium segregation is resisted indeformed grains after recovery and polygonization, boron-depleted zones seem to be quite clear inrecrystallized grains than those in deformed original grains during cooling. Subgrain boundaries andpolygonized dislocation cells have a significant effect on non-equilibrium boron segregation duringthe air-cooling. The results implicates that dislocation configuration is a more important factor affecting boron segregation at grain boundaries rather that the density of defects itself in thegrain.     

B对冷轧IF钢板焊接疲劳性能的影响

对比研究了B对Ti添加和Ti、Nb复合添加的冷轧IF钢板经电阻焊接前后的显微组织和疲劳性能的影响·结果表明,B可以细化这两种IF钢的退火组织和焊接热影响区组织,改善晶界结合强度,提高焊接疲劳强度·疲劳断口分析结果表明,IF钢焊后表现为沿晶断裂特征,B可使IF钢断裂特征得以改善,由沿晶断裂转变成穿晶断裂     

导电氮化硼热压炉微机控制系统

将STD总线工业控制机用于控制和管理导电氮化硼在高温高压下的生产过程,可以达到降低电耗21％和提高产品合格率的目的,使导电氮化硼生产的工艺条件和生产状况得到明显改善。     

STUDY FOR INCREASING ACCURACY OF INTERNAL CYLINDRICAL GRINDING

Internal cylindrical grinding is much more difficult than other grindings, because of its lowproductivity and poor quality, e. g. taper often occurs in hole after grinding, which has an effect onthe service life of the workpiece. It is a pity that internal cylindrical grinding is rarely studied. Inthis paper. aimed at the above conditions, factors affecting the accuracy of internal cylindricalgrinding are theoretically analyzed. The roller shell of the ring spinning frame(as mass part)aretaken as an example, of which internal cylindrical grinding tests are made. Tests show that thetheory conforms with practice.