颗粒尺寸对CoSb3电极电化学性能的影响

制备了颗粒尺寸不同的锂离子电池CoSb3电极材料，研究了颗粒尺寸对电极电化学性能的影响，结果表明，CoSb3的首次可逆容量从粗颗粒（约6μm）的385mAhg^-1提高到球磨粉（约100nm）的586mAhg^-1，微米尺寸CoSb3的首次不可逆容量主要是嵌锂时颗粒破碎失效引起的，而球磨纳米粉末的不可逆容量来源于锂的氧化反应和形成表面含锂化合物，球磨CoSb3的循环寿命低于期望值，但50次循环后的体积可逆容量仍比石墨负极材料高很多。     

硅酸盐玻璃中银纳米颗粒的原子状态

在硅酸盐玻璃中原位合成了平均颗粒尺寸为2．8nm、4．0nm和7．0nm的银纳米颗粒．使用银K-边X-射线吸收精细结构谱（XAFS）研究了纳米银颗粒的尺寸和玻璃基质对银原子状态和纳米银颗粒热膨胀系数的影响．结果表明,随着纳米银颗粒尺寸的减小,银原子的静态无序度增大,非和谐振动加剧．根据非和谐爱因斯坦模型和热力学微扰理论,计算了银纳米颗粒的线性膨胀系数．结果表明,纳米银颗粒越小,热膨胀系数越大．     

Dy1-xSrxFeO3的制备及其电磁吸收性能

采用传统固相法,制备了Dy1-xSrxFeO3(x=0、0.1、0.2、0.3、0.4)粉体,研究了其微波电磁性能。利用X射线衍射技术研究了其结构和相组成。利用扫描电镜观察粉体颗粒微观形貌。利用网络分析仪测试了其2～18GHz的电磁参数,并通过软件对其微波吸收性能进行了模拟,利用紫外-可见-红外分光光度计测量了其在930～1250nm波长区间的反射率。结果表明粉体为钙钛矿结构;当x=0.3,涂层厚度d=2.8mm时,在11GHz处吸收出现峰值,约为-20dB,2～18GHz范围内吸收>-10dB的频宽约为2.9GHz;当x=0.3时,粉末压片在950～1200nm波长区间的红外吸收性能最好,其反射率约为0.05%。     

壳-芯型复合陶瓷材料的制备及其电磁特性

为了提高吸波剂对电磁波的吸收性能, 采用溶胶-凝胶法制备了表面包覆有一定厚度的炭黑薄膜的钛酸钡复合粒子. 并利用XRD和TEM方法对其形貌结构进行了分析; 同时研究了复合粒子的导电性能、电磁参数以及对电磁波的吸收性能. 结果表明: 钛酸钡颗粒的直径在50～70nm之间, 包覆层厚度为10～20nm. 包覆工艺显著改善了材料的导电性能并提高了介电常数, 而且随着复合粒子在吸波材料基体中的含量不同, 对电磁波的吸收性能也有着不同的影响: 当吸收材料中复合粒子含量达到或超过20wt%时, 复合粒子明显改善了吸收材料对电磁波的吸收性能.     

纳米抗菌包装材料的开发与应用（一）

纳米颗粒通常是指颗粒尺寸介于原子与物质之间的一类粉末，这类尺寸大于原子簇（cluster），小于通常的微粉，一般在1～100nm之间。显然，纳米颗粒是肉眼和在一般显微镜下看不列的微小粒子。众所周知，一般烟尘颗粒尺寸为数微米，可见光波长尺寸为400～760hm。可见，纳米颗粒的尺寸比可见光波长还短，与病毒的尺寸相当。这样小的物质颗粒只能用高倍电子显微镜进行观测。     

共沉淀法合成ZnFe_2O_4纳米颗粒及其电磁性能研究

采用共沉淀法制备出尖晶石型ZnFe2O4纳米颗粒,通过透射电子显微镜(TEM)、X射线衍射仪(XRD)、振动样品磁强计(VSM)和矢量网络分析仪分析样品的表面形貌、晶体结构、化学成分、磁化性能和电磁性能。研究结果表明,前驱体混合物的焙烧温度为500℃时得到ZnFe2O4纳米颗粒,尺寸在14~17nm范围内,粒度分布均匀,为单晶立方结构;当焙烧温度为500~800℃时,样品表现出亚铁磁性,随着焙烧温度升高,颗粒尺寸增大,离子的倒反系数减小,饱和磁化强度降低;所选样品在2~18GHz频率范围内多次出现损耗峰,介质在松弛极化和色散过程中,将电场能转化为热能而耗散掉,从而获得良好的电磁性能。所用方法工艺简单,设备成本低。     

淀粉基碳包覆铁纳米胶囊的合成及其磁学性能

以淀粉为碳源，通过热解炭化铁／淀粉复合物，成功制备出碳包覆铁（Fe@C）纳米胶囊。在这一过程中淀粉有双重作用，既是碳源又是铁纳米颗粒的稳定剂。采用透射电镜、X射线衍射及振动样品磁强计研究了（Fe@C）纳米胶囊的结构和磁学性能。发现Fe@C纳米胶囊具有完美的铁核（bcc-Fe）／碳壳（石墨层片）包覆结构，其尺寸介于30nm～40nm之间；Fe@C纳米胶囊在室温下有低的剩磁比（Mr／Ms=0．11），表明它在室温下具有超顺磁性。     

Fe3O4包覆碳纳米管软磁性纳米复合微粒的制备及性能

用水解沉淀法在碳纳米管（CNTs）外包覆Fe3O4，制备了CNTs／Fe3O4纳米复合磁性微粒，借助透射电镜、振动探针式磁强计和外加磁场黏度计对其微观形貌、静态磁性能、沉降稳定性和磁流变性能进行了研究。结果表明：Fe3O4在碳纳米管（直径约20nm）表面形成了紧密的包覆层，微粒呈一维纳米管状结构，平均管径约60nm，平均表观密度为1．8g／cm^3，为传统磁流变液中所用铁粉等软磁性颗粒密度的四分之一。复合微粒的磁滞回线与Fe3O4纳米颗粒较为相似，具有较好的软磁性，其饱和磁感应强度（Bs）为0．21T，矫顽力（以）为7．67kA／m，用该软磁性复合微粒配制的磁流变液具有良好的沉降稳定性和磁流变特性。     

Y2O3∶Eu$1纳米晶的尺寸调控与发光性能研究

以尿素为沉淀剂,柠檬酸为表面活性剂,通过水热法得到了非晶态的水合硝酸氧钇前驱体,进一步烧结处理后生成了立方相Y2 O3纳米晶．利用X－射线衍射（ XRD）、扫描电镜（ SEM）、透射电镜（ TEM）、红外光谱（ FTIR）和荧光光谱（ PL）分别对所得样品的相结构、形貌粒度、表面结构以及发光性能进行研究．结果表明：当烧结温度从600℃升高到900℃,Y2 O3∶Eu3＋纳米颗粒的结晶性增强,并实现了粒径调控,由13．0 nm增加至27．9 nm．随着Y2 O3∶Eu3＋纳米颗粒尺寸的增加,比表面积减小会导致发光离子附近的表面晶格缺陷降低,同时纳米晶表面吸附水、硝酸根以及柠檬酸根等杂质离子逐渐被去除,减少了荧光猝灭中心,从而有利于增强荧光发射强度以及延长荧光寿命．     

纳米晶粒PLT（28）薄膜的制备和性能研究

本文首先报道了纳米晶粒ＰＬＴ（２８）薄膜的制备，并研究其微结构、铁电、电光性能，讨论不同热处理条件对薄膜微结构的影响，以及晶粒尺寸与电光性能的关系。     

Microstructure and optical properties of plasmapolymer thin films with embedded silver nanoparticles

Plasmapolymer thin films with embedded silver nanoparticles were deposited by simultaneous plasma polymerization and metal evaporation. The particle size and shape were determined by transmission electron microscopy (TEM) and analysed by optical image processing. The optical properties in the UV/ VIS/NIR spectral region were determined by the plasma resonance absorption of the silver particles. Transmittance spectra were calculated with the Bergman effective medium theory and compared with experimental spectra.     

Dielectric and pyroelectric properties of Ba-modified lead lanthanum zirconate stannate titanate ceramics

(Pb_0.97−xLa_0.02Ba_x)(Zr_0.75Sn_0.12Ti_0.13)O₃ ceramics in the composition range 0.1 ≤ x ≤ 0.16 were prepared by conventional solid state reaction process. On increasing Ba content from 0.1 to 0.16 mol, the specimens underwent phase transition from the first order to the second order and the Curie temperature decreased from 85 to 35 °C. With x = 0.16, the specimen showed good pyroelectric properties for practical applications. When a 500 V/mm dc bias field was applied, the specimen showed the maximum pyroelectric coefficient of 5800 μC/m² K and figure of merit of 58 × 10⁻⁵ Pa^−0.5 at Curie temperature.     

Engineering properties of concrete containing natural zeolite as supplementary cementitious material: Strength,toughness, durability,and hygrothermal performance

A complex analysis of engineering properties of concrete containing natural zeolite as supplementary cementitious material in the blended Portland-cement based binder in an amount of up to 60% by mass is presented. The studied parameters include basic physical characteristics, mechanical and fracture–mechanics properties, durability characteristics, and hygric and thermal properties. Experimental results show that 20% zeolite content in the blended binder is the most suitable option. For this cement replacement level the compressive strength, bending strength, effective fracture toughness, effective toughness, and specific fracture energy are only slightly worse than for the reference Portland-cement concrete. The frost resistance, de-icing salt resistance, and chemical resistance to MgCl₂, NH₄Cl, Na₂SO₄, and HCl are improved. The hygrothermal performance of hardened mixes containing 20% natural zeolite, as assessed using the measured values of water absorption coefficient, water vapor diffusion coefficient, water vapor sorption isotherms, thermal conductivity, and specific heat capacity, is satisfactory.     

基于第一性原理研究Heusler合金Fe2CuGa的结构和性能

采用基于密度泛函理论的第一性原理,系统研究了Heusler合金Fe2CuGa的结构、磁性、弹性性能和电子性质.计算结果表明:立方相的基态结构是铁磁态的Hg2CuTi结构.立方到四方的相变几乎是体积不变的,这是形状记忆合金的特性.奥氏体和马氏体的磁矩分别是4.48和4.56μB/f.u..另外,预测了Fe2CuGa的弹性系数.Fe2CuGa的立方结构在力学上是不稳定的而四方结构是稳定的.根据体模量和剪切模量的比值,发现Fe2CuGa在本质上是可延展的.利用态密度的方法解释了Fe2CuGa马氏体相变的来源.     

Preparation and characterization of organic pigments and their fluorescence properties depending on bulk structure

Fluorescent pigments, based on the optical or electrooptical properties of dyes, are the main component in fluorescent coatings and inks. In this study, three kinds of dyes (Rhodamine B, Light Green SF Yellowish, Coumarin) with four different ratios (2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%) were employed as luminophor, and the melamine-formaldehyde (MF) resin was used as curing resin to prepare fluorescent pigments in different color. Fourier transform infrared spectroscopy and X-ray diffractometry were carried out to analyze the structure of the fluorescent pigments. Scanning electron microscopy and particle size distribution were used to present the morphology of fluorescent pigments. UV–vis and fluorescence spectrum were used to demonstrate the optical properties. It can be concluded that, coumarin pigments possessed consecutive structure in MF resin while rhodamine B might be the best for the preparation of printing inks among the three kinds of dyes from the view of particle size. The TG results presented that all the pigments showed good thermal stability, which might possess potential application in high speed printing industry.     

Facile preparation of poly(vinyl alcohol) nanocomposites with pristine layered double hydroxides

In this paper, nano-sized Mg–Al layered double hydroxide (LDH) was synthesized by a fast nucleation and slow aging method. The structures of LDH were characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM) and photon correlation spectroscopy (PCS). Poly(vinyl alcohol) (PVA) nanocomposites with different LDH loadings were prepared by water solution casting method. TEM observations show that the LDH nanoplatelets are uniformly dispersed in the PVA matrix. Tensile tests indicate that the elastic modulus and the tensile strength of PVA are improved by about 15% and 54%, respectively, when incorporating with 2 wt% LDH. The improvement of mechanical properties of PVA can be attributed to fine dispersion of LDH, good compatibility and strong interaction between PVA and LDH. In addition, the presence of LDH decreases the decomposition rates at the second stage and improves the amount of residues of PVA. Meanwhile, the transparency of the nanocomposite films is maintained compared with neat PVA.     

Properties of high performance concrete containing fine-ground ceramics as supplementary cementitious material

This paper presents experimental work regarding the basic physical characteristics, mechanical and fracture-mechanics properties, durability characteristics, hydric and thermal properties of high performance concrete (HPC) with up to 60% of Portland cement replaced by fine-ground ceramics. Experimental results show that the amount of the ceramics in the mix is limited mainly by the resistance against de-icing salts which is found satisfactory only up to the cement replacement level of 10%. The mechanical and water transport properties are not significantly impaired by ceramic additions of up to 20%, whereas the effective fracture toughness, specific fracture energy, and chemical resistance (to MgCl₂, NH₄Cl, Na₂SO₄, HCl) are effectively maintained up to 40%. The frost resistance, water vapor transport and storage parameters and thermal properties are not significantly impaired even up to a 60% replacement level.     

Mechanochemical synthesis,structural, magnetic,optical and electrooptical properties of CuFeS2 nanoparticles

The rapid mechanochemical synthesis of nanocrystalline CuFeS₂ particles prepared by high-energy milling for 60?min in a planetary mill from copper, iron and sulphur elements is reported. The CuFeS₂ nanoparticles crystallize in tetragonal structure with mean crystallite size of about 38?±?1?nm determined by XRD analysis. HRTEM study also revealed the presence of nanocrystals with the size of 5–30?nm with the tendency to form agglomerates. The Raman spectrum confirms the chalcopyrite structure. Low temperature magnetic data for CuFeS₂ support the coexistence of antiferromagnetic and paramagnetic spin structure. Moreover, the hysteresis loops taken at temperatures from 5?K to 300?K revealed a presence of very small amount of ferromagnetic phase, which seems to be associated with the non-consumed elemental Fe in as-prepared nanoparticles. The optical band gap of CuFeS₂ nanoparticles has been detected to be 1.05?eV, larger than band gap of the bulk material. The wider gap possibly resulted from the nano-size effect. Photoresponses of CuFeS₂ nanoparticles were confirmed by I-V measurements under dark and light illumination. It was demonstrated that mechanochemical synthesis can be successfully employed in the one step preparation of nanocrystalline CuFeS₂ with good structural, magnetic, optical and electrooptical properties.     

X-cor夹层结构的力学性能试验研究

X-cor夹层结构比强度高,比刚度大,有望取代传统蜂窝夹层结构作为航空航天器的主承力结构材料。采用真空固化成型工艺,通过改变Z-pin的植入参数制备了X-cor夹层结构,研究了Z-pin植入角度、植入间距和直径对其平压、剪切和拉伸性能的影响。研究结果表明,Z-pin的植入参数对X-cor夹层结构的力学性能影响显著。随Z-pin植入角度的增加X-cor夹层结构的平压性能降低,剪切性能增强,拉伸模量减小,拉伸强度先增加后减小。随Z-pin植入间距和直径增加,X-cor夹层结构力学性能均增加。与泡沫夹层结构相比,X-cor夹层结构压缩、剪切和拉伸模量的测试值分别提高了1.26～5.15倍、2.50～13.56倍和1.90～2.71倍,压缩、剪切和拉伸测试值分别提高了1.63～9.20倍、1.28～2.03倍和1.01～2.30倍。