ZnS：Tb／SiO2核壳结构纳米晶的光学性质

用微乳液法合成了ZnS：Tb／SiO2核壳结构纳米晶,并通过X射线粉末衍射（XRD）、透射电子显微镜（TEM）、荧光光谱等手段对产物的结构、尺寸、形貌、荧光特性进行了表征。结果表明,ZnS：Tb纳米晶的粒径为3nm,ZnS：Tb／SiO2核壳结构纳米晶的粒径为5nm左右,这样就得出壳的厚度约为1nm。在ZnS：Tb／SiO2核壳结构纳米晶的发射光谱上可以观察到有5个发射峰为460、489、544、584和620nm,分别对应ZnS基质的发光和Tb^3＋离子的^5D4→^7F6、^5D4→^7F5、^5D4→^7F4、^5D4→^7F3跃迁。     

混凝沉淀处理含镉废水的效果及其作用机理初探

混凝沉淀工艺处理含镉废水,使处理后水体的镉浓度达到《污水综合排放标准》GB 8978—1996的0.1 mg/L排放.实验研究不同絮凝剂、絮凝剂投加量和初始pH对去除镉的影响,另对混凝沉淀后的絮体进行X射线衍射分析.结果表明无机高聚物的絮凝剂和初始pH为9的溶液对镉的去除效果较好.随着聚合氯化铝（PACI）投加量增加,当PACI盐基度为67%时,镉的去除效果明显增加.X射线衍射分析絮体中镉的结合形式主要为氢氧化镉和碳酸镉.     

Compositional complexity dependence of dislocation density and mechanical properties in high entropy alloy systems

This study focuses on a quantitative analysis of dislocation accumulation after cold plastic deformation and mechanical properties of FeNiCoCrMn and TiNbHfTaZr high entropy alloys (HEAs) which are single phase fcc and bcc solid solutions, respectively. In order to study the role of compositional complexity from unary to quinary compositions on dislocation accumulation and mechanical properties after plastic deformation, the single solid solution phase forming sub-alloys of the two HEAs were investigated. All studied samples revealed a large plastic deformability under cold-rotary swaging process by 85–90% area reduction without intermediate annealing. The dislocation density of all studied samples, determined by Williamson-Hall method on synchrotron X-ray diffraction patterns, were between 10¹⁴ - 10¹⁵ m⁻² dependent on the alloy composition. The level of dislocation density after plastic deformation is not only affected by the number of constituent element but the lattice distortion and intrinsic properties in terms of stacking fault energy, modulus misfit, and melting point also impact the dislocation storage. The level of dislocation density determines the level of mechanical properties because of a resistance to dislocation motions. The hardness and yield compressive strength of the studied samples are proportional to the level of dislocation density.     

碳化硅空间用反射镜坯体残余应力的研究

采用反应烧结工艺制备了碳化硅空间用反射镜坯体.通过X射线衍射方法,测定了碳化硅空间用反射镜坯体的残余应力.结果表明,反射镜坯体镜面存在较大的残余应力,测量值具有一定的随机性,测量误差与测量值具有一定的相关性.采用有限单元法计算了反射镜坯体的热残余应力,通过对比验证了测试结果可靠性.     

[Zn(IBG)(H2O)3]·2H2O配合物的合成、结构和热稳定性研究

合成了化合物[Zn(IBG)(H2O)3].2H2O(H2IBG=1,3-苯二甲酰二甘氨酸),并通过X射线衍射对其单晶结构进行了测定.该结构属于正交晶系,空间群C222(1),分子量Mr=431.65,晶胞参数a=0.693 01(14)nm,b=0.772 56(14)nm,c=23.006 4(6)nm,V=1.609 61nm3,Z=4,Dc=1.781g.cm-3,F(000)=888.0.由于分子内和分子间氢键,使得分子结构更趋稳定.通过红外光谱(IR)、热重分析及XRD对化合物进行了表征.     

化学沉淀法和溶胶- 凝胶法制备纳米二氧化钛及其抑菌性的研究

用化学沉淀法和溶胶-凝胶法制备纳米二氧化钛颗粒;利用X射线衍射和紫外-可见光吸收光谱分析法,重点研究氨水浓度和煅烧温度对二氧化钛纳米晶生长及其光学性质的影响.结果表明:氨水浓度的上升有利于纳米晶粒径的下降;煅烧温度的上升能促进结晶度的上升,同时煅烧温度和结晶度对粒径也有影响.随着粒径的下降,纳米晶的光吸收边蓝移.在得到颗粒的各项性质参数后,实验验证了普通日光灯下纳米二氧化钛颗粒的光催化抑菌性能.     

用Gd2O3和B4C制备GdB6过程中的化学反应

研究了Gd2O3与B4C在碳管炉中,Ar气氛下制备GdB6过程中的化学反应.XRD和TG-DTA实验研究结果表明:在367~458℃期间,主要是样品中残留的杂质C和O2发生反应;800~1 200℃时,Gd2O3与B4C生成GdBO3,GdBC和B;并同时存在GdBO3,GdBC与B4C生成GdB4;Gd2O3与B4C生成GdB6.随温度升高,GdB4生成反应速度加快.1 470℃时,GdB4和B反应生成GdB6,GdB6的生成率随反应时间延长而增加,6 h时生成率达到了97.8%.     

纳米Zn粉氧化行为的研究

以电弧法制备的纳米Zn粉为原料,采用在空气中露置的方法对其进行氧化,利用X射线（XRD）、透射电镜（TEM）、扫描电镜（SEM）及能谱研究了纳米Zn粉氧化后的形貌、显微结构、含氧量和氧原子的位置,比较了氧化与未氧化的纳米Zn粉中氧含量随时间的变化情况。     

Structural, electrical, dielectric and magnetic properties of Mn-Nd substituted CoFeO3 nano sized multiferroics

A series of Mn x Co_(1-x) Fe_(1-y) Nd_yO_3(where x=0.0–1.0 y=0.0–0.1) multiferroic nanocrystals was synthesized via sol-gel auto-combustion technique. The structure was confirmed by X-ray diffraction(XRD)while morphology was investigated by scanning electron microscopy(SEM). The electrical resistivity was observed to increase from 2.14 * 10~7 to 8.77 * 10~9 Ω-cm and activation energy was found to increase from 0.64 to 0.75 e V, while the drift mobility decreased from 4.75 * 10~(-13) to 1.27 * 10~(-15)cm~2V~(-1)S~(-1) by the substitution of Mn and Nd contents. The dielectric constant, dielectric loss and dielectric loss factor decrease with frequency and Mn-Nd contents. The saturation magnetization was increased from 34 to 70 emu g~(-1) while the coercivity decreased from 705 to 262 Oe with the increase of substituents.The increase in electrical resistivity and saturation magnetization while decrease in dielectric parameters and coercivity make these nanomaterials suitable for applications in microwave devices and longitudinal magnetic recording media.     

ZrO2(3Y)增韧增强WC-20%Co金属陶瓷复合材料

采用热等静压真空烧结工艺制备了不同含量ZrO2(3Y)/WC-20%Co金属陶瓷复合材料.对复合材料进行了硬度、抗弯强度和冲击韧性等力学性能测试,用扫描电子显微镜(SEM)分析了微观组织及冲击断口成分,用X射线衍射定量分析计算了力学性能试验前后t→m相变量.实验表明:ZrO2(3Y)在WC-20%Co基体中呈球形,均匀分布在Co相和WC相中,该复合材料抗弯强度和冲击韧性明显提高,硬度指标提高不明显.