4 ) doping cou1d res tra in par t ic1es " growing , the samples ' s ize became 1ess wi th surface coat ing , and pre - - treatment temperature for the dry - - ge1 of samples for coating was not suitable if it was too high . 5 ) the samples with pd doping had better sens it ivi ty and se1ect ivi ty 晶粒度较大的sno _ 2样品在室温至15k的温度范围内，表现为半导体特性； 7 )掺杂使样品电阻增大，在一定温度下出现了半导体-绝缘体的转变，并且表面包覆样品的转变温度比均匀掺杂样品高。
In our experiments , we prepared mnzn ferrite powders using sol - gel auto - combustion successfully . their crystalline structure and phase are discussed by x - ray diffraction instruction . in order to know of them more exactly , we also took transmission electronic photography ( tem ) of the powders , and measured the magnetic properties of many mnzn ferrites 实验中，我们对用sol - gel法制备出软磁锰锌铁氧体粉的晶粒度及物相进行了x射线衍射( xrd )的测试分析，同时运用透射电镜( tem )对粉料进行形貌观测，系统地测量了大量mnzn铁氧体实验样品的磁性能。
Coarse - grained impact resistant grades for mining , working of stones and rock , building , mineral oil industry , percussion and hammer drill tips , inserts for mining cutters , chisels , asphalt cutters , picks , inserts for concrete - working , hammer cheeks rolls , hot wire rolling , ball pressure dies , brake blocks 粗晶粒度的抗冲击牌号，适用于采矿工业、采石、建筑、石油钻探工业、钻头和锤头、矿刀的衬垫、凿子、沥青切刀、风镐、混凝土制造的衬垫、锤子的滚轴、热轧轧辊、子弹压力冲模、刹车片。
Using sncl4 - 5h2o and sbcl3 as precursors , antimony doped tin oxide particles with good electrical properties have been prepared by hydrothermal synthesis . the optimal conditions of this synthesis process were as following : doping ratio was 11 % ; reaction temperature was 180 ; reaction time was 2h ; the temperature and time of calcinations is 700 and 2h . the size of ato particles obtained is about 20nm , and its resistance can reach 0 . 2 , under 0 . 2mpa pressure 在掺杂浓度为11 ，水热反应温度为180 ，反应压力1mpa ，反应时间2h ，热处理温度为700 ，热处理时间2h的实验条件下制备的ato粉体，性能达到最佳，晶粒度在20个nm左右，在0 . 2mpa压力下粉体电阻值为0 . 2 。
Due to the rapid heating rate , the time for wire stayed in high temperature zone is very short and no enough time for grain grows largely , hence the structure size of continuously induction heated wire is smaller than that of conventional heated wire and grain size is 2 to 4 level higher . due to the fine grain size , the induction heat oil tempered spring wire can acquire more reasonable comprehensive mechanical properties under same strength 可见，由于加热快，在高温停留时间短，组织晶粒来不及长大，因此，连续感应加热钢丝的组织晶粒尺寸比一般加热小，晶粒度高2 - 4级。由于组织晶粒尺寸细小，因此，感应加热油淬火-回火钢丝，在同样强度下，具有更高的综合b力学性能。
