纳米晶软磁合金中的结构对技术磁性的影响——Ⅱ.磁弹耦合作用

对磁弹耦合在决定纳米晶软磁合金宏观磁性中的作用进行了探讨,高场磁化规律以及正电子湮没测量表明:对Fe_73.5Cu₁Nb₃Si_13.5B₉合金,准位错偶极子造成的应力场对畴壁的钉扎效应是造成纳米晶软磁合金矫顽力的重要原因;结构缺陷造成的应力场与磁致伸缩的耦合作用对纳米晶软磁性能有重要的影响.在结构各向异性和磁弹耦合能共同作用下可解释纳米晶合金表现出最佳软磁性能.     

Si1－xGex/Si量子阱发光材料的分子束外延生长及其结构研究

采用固源Si分子束外延,在较高的生长温度于Si(100)衬底上制备出Si1－xGex/Si量子阱发光材料。发光样品的质量和特性通过卢瑟福背散射、X射线双晶衍射及光致发光评估。背散射实验中观察到应变超晶格的反常沟道效应;X射线分析表明材料的生长是共度的、无应力释放的,结晶完整性好。低温光致发光主要是外延合金量子阱中带边激子的无声发射和横光学声子参与的激子复合。并讨论了生长温度对量于阱发光的影响。     

NaNO3掺杂Y2O3材料的制备及电流变性质

利用NaCO3和Y（NO3）3做主要原料，合成了一系列用稀土氧化物（Y2O3）作为基础材料的新型电流变材料——NaNO3掺杂Y2O3材料。对于这些材料的介电性质、微观结构和电流变性能的研究结果表明，NaNO3的掺杂可以明显地提高Y2O3材料的电流变活性。材料在二甲基硅油中的悬浮液的剪切应力随NaNO3在Y2O3中的掺杂程度有明显变化，当Na／Y（物质的量的比）为0．6时材料的电流变性能最好，     

Dextran-modified iron oxide nanoparticles

Dextran-modified iron oxide nanoparticles were prepared by precipitation of Fe（Ⅱ） and Fe（Ⅲ） salts with ammonium hydroxide by two methods. Iron oxide was precipitated either in the presence of dextran solution, or the dextran solution was added after precipitation. In the second method, the iron oxide particle size and size distribution could be controlled depending on the concentration of dextran in the solution. The nanoparticles were characterized by size-exclusion chromatography, transmission electron microscopy and dynamic light scattering. Optimal conditions for preparation of stable iron oxide colloid particles were determined, The dextran/iron oxide ratio 0-0,16 used in precipitation of iron salts can be recommended for synthesis of nanoparticles suitable for biomedical applications, as the colloid does not contain excess dextran and does not coagulate.     

Nd：YVO4晶体α向生长研究

采用固-液两相混合，使Nd2o3、Y2O3和V2O5在近常温条件下初步合成Nd：YVO4多晶原料，降低固相合成反应温度，减少V2O5在多晶原料制备过程中的挥发。讨论了α方向V单晶生长条件，采用提拉法，以(100)方向进行单晶生长，得到一系列掺杂浓度的Nd：YVO4单晶。     

Measurement of the Distribution of Magnetic Field in Gyrotron of ECRH System on HL-2A Tokamak

In ECRH system of HL-2A tokamak, we chose a new type of gyrotron imported from Russia. We finished the installation and testing last year with the help of Russian experts. We got a lot of useful data and satisfying results after our experiments with the operating of gyrotron.     

当△=AC—B^2=0时,对二元函数极值的探讨

设二元函数f(x,y)有稳定点P(x_0,y_0),并设f_(xx)(x_0,y_0)=A,f″_(xy)(x_0,y_0)=B,f″_(yy)(x_0,y_0)=C,△=AC-B~。当△=AC-B~2=0时,f(x,y)在点P(x_0,y_0)处是否有极值的问题,一般教科书都未进行过具体地讨论,本文对这一问题进行了初步地探     

Effects of Substrate Temperature on Helium Content and Microstructure of Nanocrystalline Titanium Films

Helium-charged nanocrystalline titanium films have been deposited by HeAr magnetron co-sputtering. The effects of substrate temperature on the helium content and microstructure of the nanocrystalline titanium films have been studied. The results indicate that helium atoms with a high concentration are evenly incorporated in the deposited titanium films. When the substrate temperature increases from 60℃ to 350℃ while the other deposition＇parameters are fixed, the helium content decreases gradually from 38.6 at.% to 9.2at.%, which proves that nanocrystalline Ti films have a great helium storage capacity. The 20 angle of the Bragg peak of （002） crystal planes of the He-charged Ti film shifts to a lower angle and that of （100） crystal plane is unchanged as compared with that of the pure Ti film, which indicates that the lattice parameter c increases and a keeps at the primitive value. The grain refining and helium damage result in the diffraction peak broadening.     

聚二甲基二烯丙基氯化铵的合成,表征及抗菌性能

65％的二甲基二烯丙基氯化铵（DADMAC）单体水溶液通过自由基聚合得到分子量约为5000的聚二甲基二烯丙基氯化铵（PDADMAC）均聚物。用红外光谱，核磁共振，X射线衍射仪，粘度法和扫描电镜对PDADMAC进行结构分析和表征。合成聚合物的抗霉菌实验表明，PDADMAC对多种霉菌有抑制作用，具有较宽的抑菌谱；抗细菌实验表明，PDADMAC对金黄色葡萄球菌，大肠杆菌，枯草芽孢杆菌具有不同程度的抑制作用。     

关于局部对称空间中2-调和子流形

本文研究局部对称完备黎曼流形中的紧致2－调和子流形，得到了这类流形第二基本模式长平方的Pinching定理及推广的J．Simons型积分不等式。