强流回旋加速器综合试验装置的磁场测量与垫补

强流回旋加速器综合试验装置的主体是一台紧凑型回旋加速器,加速器主磁铁材料的不均匀性,磁铁加工和安装的非理想因素将引起中心平面的磁场的非理想分布,因此有必要对其中心平面的磁场进行测量和垫补.本文主要讲述该综合试验装置的霍尔感应磁场测量系统的设计和使用;通过磁场测量数据分析进行镶条的再加工,最终实现对等时性磁场和束流的纵向聚焦的垫补;研究与实践了一种对磁场一次谐波进行垫补的方法,垫补的结果满足了设计的要求.     

Nonlinear stress and deformation analysis of thin current-carrying strip-shells

The problems of nonlinear deformation of a thin current-carrying shell under the coupled action of an unsteady electromagnetic field and a mechanical field are studied. The nonlinear magneto-elastic kinetic equations, the physical equations, the geometric equations, the electrodynamics equations, and the expressions of Lorentz force of a thin current-carrying shell under the action of a coupled field are given. Normal Cauchy form nonlinear differential equations, which include ten basic unknown functions in all, are obtained by the variable replacement method. Using the difference and quasilinearization methods, the nonlinear magneto-elastic equations are reduced to a sequence of quasilinear differential equations, which can be solved by the method of discrete orthogonalization. Numerical solutions for the stresses and deformations in the thin current-carrying strip-shell with two simply supported edges are obtained by considering a specific example. The results that the stresses and deformations in a thin current-carrying strip-shell with two simply supported edges change with variation of the electromagnetic parameters are discussed, through a special case. It is shown that the deformations of the shell can be controlled by changing the electromagnetic parameters Published in Prikladnaya Mekhanika, Vol. 43, No. 9, pp. 130–144, September 2007.     

碳包覆改性制备高倍率性能的锂离子电池正极材料LiNi1/3Co1/3Mn1/3O2

采用碳酸盐共沉淀-高温固相法制备了一系列表面碳包覆改性（w=1.0%,2.0%,3.0%）的LiNi_1/3Co_1/3Mn_1/3O₂正极材料,借助X射线衍射（XRD）分析、扫描电镜（SEM）、透射电镜（TEM）、电化学阻抗谱（EIS）和恒电流充放电测试等表征手段对材料的晶体结构、微观形貌和电化学性能进行了较系统的研究。结果表明,碳成功地包覆在了材料颗粒的表面,碳包覆改性后的材料具有良好的α-NaFeO₂结构（空间群为R3m）,且随着包碳量的增加,一次颗粒平均尺寸逐渐增大（从177 nm增至209 nm）。表面的无定形碳层可以提高材料的电子导电率,减少电极材料与电解液的副反应,故而碳包覆材料的电化学性能都有了一定程度提升。包覆碳量为2.0%的样品高倍率和长循环性能最好,在2.7~4.3 V,1C下循环100次后,容量保持率为93%;在0.1C、0.2C、0.5C、1C、3C、5C、10C和20C时的放电比容量分别为：155、148、145、138、127、116、104和96 mAh·g^-1。在超高倍率50C（9 A·g^-1）时,其放电比容量还能达到62 mAh·g^-1（原始LiNi_1/3Co_1/3Mn_1/3O₂材料仅为30 mAh·g^-1）,倍率性能十分优异。     

加速溶剂萃取凝胶色谱净化气相色谱-质谱联用测定土壤中多环芳烃

土壤样品经过加速溶剂萃取仪与凝胶色谱净化浓缩提纯处理后,用气相色谱-质谱联用仪测定土壤中多环芳烃。     

Solvent-dependent luminescent Cu(I) framework based on 5-(4-pyridyl)tetrazole

A new Cu(Ι) coordination compound, Cu₄(L)₄·2EtOH (1), has been obtained from the solvothermal reaction of CuBr, HL (L=5-(4-pyridyl) tetrazole), EtOH and NH₃·H₂O. The structure determination reveals that 1 has a 2D network, where each Cu(I) atom adopts a trigonal coordination mode. The 2D networks stacked in an ABAB sequence through the π–π interaction to form a 3D supramolecular framework, giving a 1D channel along the b-axis. The TGA and powder XRD measurements reveal that the framework is stable after removal of the guest molecules. Gas (N₂) adsorption measurement was carried out for the framework. Framework 1 shows II sorption profile with N₂, which indicates that N₂ molecules cannot diffuse into the micropore and only surface adsorption occurs. The photoluminescent research shows that compound 1 displays an interesting solvent-dependent luminescence.     

环形光子晶体光纤中涡旋光的传输特性研究

由于涡旋光具有轨道角动量,将它应用于光纤通信领域可以有效提高信息传输速率.设计了一种环形光子晶体光纤,利用COMSOL Multiphysics软件对其涡旋光TE01,HE±21和TM01模式特性进行模拟计算,它们之间有效折射率差分别为4.59×10~(-4)和3.62×10~(-4);其中,TE01模式的涡旋光在入射光波长范围为1650—1950 nm时,色散值在44.18—45.83 ps·nm~(-1)·km~(-1)之间平坦;入射光波长在1550 nm时,TE01模式的涡旋光的非线性系数为1.37 W~(-1)·km~(-1).该结构的光子晶体光纤的涡旋光具有损耗小、色散平坦等特性,对光纤中传输涡旋光、将涡旋光应用于超连续谱等方面的研究具有重要意义.     

纳米金刚石的分散、修饰及载药应用研究

纳米金刚石(nanodiamond,ND)作为一种重要的碳纳米材料,具有表面易修饰、比表面积大、生物毒性低以及物理化学稳定性好等特点,使其在生物医学领域具有独特的优势.本文通过对ND进行分散和化学修饰得到了分散性良好的羧基化纳米金刚石(ND-COOH),并通过透射电子显微镜、X-射线衍射、傅里叶变换红外谱仪等手段对其形貌和结构进行了表征分析.ND-COOH在水溶液中水解后呈现出较高的负电位,致使其可以通过静电相互作用吸附带正电的抗癌药物盐酸阿霉素(dox),且对阿霉素的负载量可达325μg/mg.由于ND-COOH与dox之间通过带负电的羧酸根与带正电的质子化氨基结合,因此在H~+浓度较高的酸性溶液中,药物复合体ND-dox呈现出显著的p H值依赖药物释放特性,在p H值为5.0的磷酸盐缓冲液中药物释放率达到85%,而在p H值为7.4的PBS中药物释放率低于40%.此外,ND-COOH和ND-dox的细胞毒性和体外细胞杀伤能力结果表明,ND-COOH在0—150μg/m L范围内对细胞活性没有明显抑制,而ND装载药物dox后的ND-dox对SGC-7901胃癌细胞活性则表现出显著的抑制作用,表明ND-COOH作为药物载体具有较低的生物毒性,而负载药物后则对肿瘤细胞具有较强的杀伤能力.通过对ND进行简单的分散和表面改性,使ND具备良好的药物装载和独特的p H值依赖药物释放特性,这对于促进纳米金刚石在药物载体方面的应用具有重要的借鉴意义.     

Numerical simulation of stress field for laser thermal loading on piston

To investigate the laser thermal loading on diesel engine piston, the employed Gaussian laser beam was transformed into concentric multi-circular patterns of specific intensity distributions with the aid of diffractive optical elements (DOEs), the time duration of laser thermal loading was controlled by computer with air cooling on the top surface of piston, and water cooling of oil tunnel and bottom surface of piston. Numerical simulation model of stress field of laser thermal action was established with the consideration of experimental conditions and the temperature dependent of thermal physical properties of the piston materials. Results show that the stress fluctuation rate at the concave pit site of top surface of piston is larger than that of laser irradiated region due to concave pit region near oil tunnel. Meanwhile, the regions of concave pit, oil tunnel and inner chamber near the top surface of piston are most vulnerable sites to form thermal cracks due to their direct contact with the cooling medium. Results of experimental and numerical simulation have good agreement, which validates the numerical simulation mode.     

纳米SnO2的水热合成

以ＳｎＣｌ４．５Ｈ２Ｏ为原料，用水热法制备了粒度均匀的纳米ＳｎＯ２微粉，研究了反应温度，介质的酸度和反应物浓度等因素对ＳｎＯ２微晶形成，粒子尺寸及产率的影响。Ｘ射线物相分析表明，在酸性介质中，不同温度（１２０～２２０℃）下所形成的产物都是四方晶系ＳｎＯ２，适当降低反应介质的酸度有得于ＳｎＯ２粒子尺寸的减小和产率的提高，随反应温度升高，ＳｎＯ２粒子逐渐长大，当ｐＨ＝１．４５时，粒子的平均尺寸由大约２     

新型三组元喷嘴雾化特性研究

设计了新型三组元喷嘴,由两级离心内喷嘴和内混式外喷嘴装配为同轴式结构,通过燃料在内混腔里形成的两相流对液氧进行雾化。试验结果表明,上排孔进氧的双组元工况雾化质量高;三组元工况时存在两种雾化机理,并有较高雾化质量。