共混聚合物单离子导体的导电性与传质机理研究

本文研究了聚甲基丙烯酸乙基磺酸锂/聚(甲基丙烯酸齐聚氧化乙烯醋一丙烯酰胺)/二甲基多缩乙二醇共混聚合物单离子导体导电性和传质机理。用极化反转法测定了共混物的离子淌度。在25℃,该共混物单离子导体电导率和锂离子淌度分别为5.2×10~(-6)s·cm~(-1)和3.0×10~(-8)cm~2·V~(-1)·s~(-1)。由离子淌度计算得到50℃时锂离子扩散系数和迁移数分别为4.2×10~(-9)cm~2·s~(-1)和0.994。实验结果证实该共混物是一种单阳离子导体,是通过热活化跳跃机制完成阳离子传质过程的.     

β因子校正法测定Pb-Cu、Bi-Cu合金表面张力

采用座滴法技术,通过“软件化”的自编 B-A 表和相应的β因子校正法程序,测定了 Pb-Cu,Bi-Cu 合金的表面张力。测定结果表明:Pb-7%wtCu 的元合金在850℃、900℃;Bi-26%Cu 二元合金在850℃的表面张力值分别为408×10~(-3)N·m~(-1)、427×10~(-3)N·m~(-1)以及343×10~(-3)N·m~(-1)。分析和讨论了测量与计算过程中的影响因素。     

金属—PAN—S配合物的极谱研究——Ⅱ:Fe~(3+)—PAN—S—TEA—NH_3·H_2O—NH_4Cl体系配合吸附波

在NH_3·H_2O—NH_4Cl—三乙醇胺底液中Fe(Ⅲ)与PAN—S产生一灵敏的配合吸附波,峰电位在—0.50伏(vs.SCE)。峰电位与铁离子浓度在2.8×10~8～3.4×10~(-6)mol/L范围内线性良好,检出下限可达2.8×10~(-8)mol/L。该法用于乳粉、头发、血清等样品的测定,结果满意。     

日本东北金属生产的镧塔耐特(Lanfhanet)永磁合金

日本东北金属是在日本最早(1969年6月)研究以钐为主要成分的稀土-钴金属间化合物永磁—镧塔耐特合金的。大量生产的有最大磁能积为8×10~6高·奥的镧塔耐特8和最大磁能积为10×10~6高·奧的镧塔耐特10。在电子钟、拾声器、微型马达和电子仪表等中的应用得到好评。其特性如表所列。     

聚酰亚胺箔式电阻应变片的制造

聚酰亚胺箔式电阻应变片在国外已经普遍作为高精密级电阻应变片使用。这是因为用作应变片基底材料的聚酰亚胺粘合剂具有以下几个特性: 1.优良的电性能:体积电阻1.4×10~(16)欧姆·厘米,表面电阻2.8×10~(14)欧姆,介电常数3.34,介电损耗1.44×10~(-2),因此有很高的绝缘电阻。 2.很好的粘接性能。即使在250℃高温下     

Pd-Au系新型无磁艾林瓦型合金“Pallagold”

一、前言 Kesterr和Koch与Danneker在测定退火Pd的弹性模量E的温度变化时,发现在500℃附近,温度系数e比较小,而常温下的e值分别为-9×10~(-5)和-8×10~(-5)左右。其后Rayne制备了Pd单晶并在-268.9°～26.1℃温域内测Pd单晶的E值     

异鼠李素的电化学行为及其测定

采用循环伏安法研究异鼠李素在电极上的电化学行为,建立差示脉冲伏安法测定其含量的电化学分析新方法。在pH 4.0醋酸盐缓冲液中,氧化峰电流与异鼠李素浓度在2.0×10~(-7)～1.2×10~(-6)mol·L~(-1)范围内呈良好的线性关系,检测限为3.0×10~(-8)mol·L~(-1)。玻碳电极可有效消除样品中其它组分对异鼠李素测定的干扰,已成功用于实际样品中异鼠李素含量的直接测定。该方法灵敏度高、检测范围宽,结果令人满意。     

使用Fabry—Perot干涉腔稳频的GaAlAs激光器(英文)

GaAlAs激光器的激射频率被锁定于Fabry-Perot干涉腔上。在锁定之后其激射频率的涨落已被大大地降低。所测得的频率稳定度(对Fabry-Perot干涉腔中心频率的跟踪稳定度)如下:其中第1个稳频系统为5×10~(-12)(1s)、1.5×10~(-12)(10s)、1.2×10~(-12)(100s);而第2个稳频系统为8×10~(-12)(1s)、2×10~(-12)(10s)、1.8×10~(-12)(100s)。     

反相高效液相色谱法同时测定洁康舒洗剂中三组分的含量

建立反相高效液相色谱法同时测定洁康舒洗剂中大黄酸、大黄素和大黄酚含量的方法。采用反相高效液相色谱法。symmctry C18柱(3.9×150mm,5μm)流动相为甲醇—水—磷酸(80:20:0.1);流速为1.0mL·min-1;检测波长为432nm。大黄酸、大黄素和大黄酚的回归方程分别为:C1=7.3159×10-1+1.8966×10-5A,r=9994,C2=1.0513+1.5680×10-5A,r=0.9999C3=1.2260-1.4684×10-5A,r=0.9999三者分别在7.60~38.0μg·mL-1、1.75~8.75μg·mL-1、2.4~12.OOμg·mL-1范围内呈线性关系。平均回收率和RSD分别为98.02%、96.63%、97.05%和1.78%、1.20%、1.15%。该方法操作简便,测定结果准确可靠,可用于测定洁康舒洗剂中大黄酸、大黄素和大黄酚的含量。     

锑掺杂二氧化锡薄膜的导电机理及其理论电导率

归纳总结了锑掺杂二气化锡(ATO)的导电机理,晶格的氧缺位、5价Sb杂质在SnO_2禁带形成施主能级并向导带提供n-型载流于是ATO导电的两种主要机理。从材料的电导率公式出发,定性分析了二氧化锡中掺杂锑的含量存在理论最佳值,根据已有模型计算证明了锑掺杂二氧化锡电导率存在理论上限。掺杂二氧化锡中锑的最佳理论含量为1.49％(质量分数),锑掺杂二氧化锡理论电导率最高为0.2×10~4(Ω·cm)~(-1),氧空位对ATO电导率的贡献为0.1392×10~4(n·cm)~(-1),大于掺杂电子对ATO电导率的贡献(0.061×10~4(Ω·cm)~(-1))。     

Estimation on Magnetic Refrigeration Material （Gd1-xREx）5Si4 （RE=Dy, Ho）

A systematic (Gd1-xREx)5Si4 (RE=Dy, Ho) alloys are investigated to estimate their magnetocaloric effect.The Curie points of (Gd1-xREx)Si4 alloys can tunable from 266 K to 336 K when RE=Dy, Ho; x=0～0.35 and 0～0.15, respectively, and decrease nearly linearly with increasing x. These alloys keep orthorhombic structures Ge5Sm4 and exhibit second order transition when they experience in a change magnetic field at about Curie when magnetic field changes 0～2 T. The adiabatic temperatures changes (△Tad) of these alloys at Curie points are larger than 1 K in a field change 0～1.4 T, the curve of △Tad is wide as that of Gd. The relative cooling power is about 0.8～0.9 J/cm3 when field changes 0～2 T, 55% of that of Gd. Comparing with Gd5(Si1-xGex)4, these alloys do not contain expensive element Ge, so that their cost are lower than the former. Because they could work at temperature region 260～340 K due to their Curie points can be tuned, which is an advantage comparing with Gd, these alloys are potential magnetic refrigerants working in a magnetic refrigerator with a low magnetic field at room temperatures.     

A constitutive model for fcc crystals with application to polycrystalline OFHC copper

Based on the results of a series of experiments on commercially pure OFHC copper (an fcc polycrystal), a physically based, rate- and temperature-dependent constitutive model is proposed for fcc single crystals. Using this constitutive model and the Taylor averaging method, numerical calculations are performed to simulate the experimental results for polycrystalline OFHC copper. The model calculation is based on a new efficient algorithm which has been successfully used to simulate the flow stress of polycrystalline tantalum over broad ranges of temperature, strain rate, and strain (Nemat-Nasser, S., Okinaka, T., Ni, L., 1998. J. Mech. Phys. Solids 46, 1009). The model effectively simulates a large body of experimental data, over a broad range of strain rates (0.001–8000 s⁻¹), and temperatures (77–1096 K), with strains close to 100%. Few adjustable constitutive parameters of the model are fixed at the outset for a given material. All other involved constitutive parameters are estimated based on the crystal structure and the physics of the plastic flow.     

Physical Virology: Direct Measurement of Phage phi29 Stiffness Provides Evidence of Internal Pressure (Small 15/2012)

A 3D AFM topography rendition of a phage phi29 (red) adsorbed on mica (blue) is shown by P. J. de Pablo and coworkers, where part of the viral DNA (yellow) has been ejected through the tail. The phi29 bacteriophage translocates part of its DNA into the host by releasing the elastic energy arising from the internal pressure created during the DNA-packing process. Pushing with the AFM tip on the phage enables the direct measurement of the stiffness to estimate its internal pressure, just as a tyre may be pressed with fingers.     

Coagulation characteristics of titanium (Ti) salt coagulant compared with aluminum (Al) and iron (Fe) salts

In this study, the performance of titanium tetrachloride (TiCl(4)) coagulation and flocculation is compared with commonly used coagulants such as aluminum sulfate (Al(2)(SO(4))(3)), polyaluminum chloride (PACl), iron chloride (FeCl(3)), and polyferric sulfate (PFS) in terms of water quality parameters and floc properties. TiCl(4) flocculation achieved higher removal of UV(254) (98%), dissolved organic carbon (DOC) (84%) and turbidity (93%) than other conventional coagulants. Charge neutralization and physical entrapment of colloids within coagulant precipitates and adsorption, seemed to play a significant role during TiCl(4) flocculation, while the main mechanism for conventional coagulants was bridge-aggregation and adsorption. The aggregated flocs after TiCl(4) flocculation showed the fastest growth rate compared to the other coagulants, with the largest floc size (801 μm) occurring within 8 min. The floc strength factor of PACl, Al(2)(SO(4))(3), PFS, FeCl(3) and TiCl(4) was 34, 30, 29, 26 and 29, respectively, while the floc recovery factor of the TiCl(4) coagulant was the lowest. Based on the results of the above study, it is concluded that the TiCl(4) flocculation can reduce the hydraulic retention time of slow and rapid mixing, however, careful handling of sludge is required due to the low recoverability of the aggregated floc.     

工艺参数对Ar~+改性无氧铜表面形貌及二次电子发射的影响

为了降低材料的二次电子发射系数,本文对高导电无氧铜(OFHC,简称无氧铜)进行离子束表面改性处理,并研究其最优工艺条件,重点考查了温度、时间等工艺参数对表面形貌以及二次电子发射系数(δ)的影响。利用扫描电镜、能谱仪等对表面形貌及成分进行分析并在此基础上对改性后样品的表面形貌形成机理进行了初步探讨。实验得出最佳工艺为:在600℃下离子束改性处理1 h。该参数下处理的无氧铜样品的二次电子发射系数降低63.5%。     

Modelling of strain hardening and microstructural evolution in equal channel angular extrusion

Strain hardening as well as crystallographic texture development is studied in polycrystalline OFHC Cu subjected to equal channel angular extrusion (ECAE) up to four passes. The experiments have been carried out at room temperature in a 90° die, following Route A processing. Texture development was followed using pole figures and hardening was measured by Vickers hardness testing. The self-consistent viscoplastic polycrystal plasticity model in its isotropic version [Acta Met. Mater. 42 (1994) 2453] was used for modelling the evolution of the texture. A previously proposed strain-hardening model [J. Eng. Mater. Techn. 124 (2002) 71], based on the dislocation cell structure of the material, was incorporated into the polycrystal model to predict the hardening behaviour. For the passage of the material in the ECAE die, the recently proposed flow line model was employed [Adv. Eng. Mater. 5 (2003) 308]. The experimental textures as well as the hardening curves are qualitatively reproduced by this modelling and an important effect of the varying strain rate within the ECAE die on hardening has been found.     

Effect of Initial Annealing Temperature on Microstructural Development and Microhardness in High‐Purity Copper Processed by High‐Pressure Torsion

The effect of the initial annealing temperature on the evolution of microstructure and microhardness in high purity OFHC Cu is investigated after processing by HPT. Disks of Cu are annealed for 1 h at two different annealing temperatures, 400 and 800 °C, and then processed by HPT at room temperature under a pressure of 6.0 GPa for 1/4, 1/2, 1, 5, and 10 turns. Samples are stored for 6 months after HPT processing to examine the self‐annealing effects. Electron backscattered diffraction (EBSD) measurements are recorded for each disk at three positions: center, mid‐radius, and near edge. Microhardness measurements are also recorded along the diameters of each disk. Both alloys show rapid hardening and then strain softening in the very early stages of straining due to self‐annealing with a clear delay in the onset of softening in the alloy initially annealed at 800 °C. This delay is due to the relatively larger initial grain size compared to the alloy initially annealed at 400 °C. The final microstructures consist of homogeneous fine grains having average sizes of ≈0.28 and ≈0.34 µm for the alloys initially annealed at 400 and 800 °C, respectively. A new model is proposed to describe the behavior of the hardness evolution by HPT in high purity OFHC Cu.     

圆柱壳体冲击平板靶的实验与数值研究

利用一级气炮进行了高导无氧铜(OFHC)圆柱壳冲击平板靶实验,对圆柱壳进行回收观测。采用Johnson-Cook(J-C)和Zerilli-Armstrong(Z-A)两种本构模型对实验进行了数值模拟,数值模拟与实验观测的壳体变形比较表明:采用J-C本构模型计算的结果与试验更接近。本构模型的影响是明显的,采用J-C本构模型和Z-A本构模型数值模拟的圆柱壳中的应变、速度以及吸能的历史有较大差异。     

Strain-hardening effects in bcc,fcc, and hcp metals loaded at very high rates

Plastic deformation in typical bcc, fcc and hcp metals has been studied as a function of initial impact energy (up to about 4200 J). Materials included 1100-F aluminium, 2024-T3 aluminium, lead, OFHC copper, type-200 nickel, columbium, tantalum, vanadium, molybdenum, and cadmium. Macroscopic deformation resulting from projectile impacts at velocities up to 8 km/sec was recorded by sub-microsecond photography and flash X-radiography. A correlation was established between homologous test temperature (T/T _m) and size of craters resulting from impact, as was a relationship between the relative increase in microhardness in the impact affected region beneath the target crater and impact stress over the square root of compressibility. The microstructures of impulse-loaded regions were correlated with the stress levels effecting them. Strain profiles beneath the impact position for the type-200 nickel were determined metallographically and correlated with microhardness profiles.     

Ionic-liquid-induced microfluidic reaction for water-soluble Ce(1 - x)Tb(x)F3 nanocrystal synthesis

Luminescent lanthanide nanocrystals (NCs) are proposed to be a promising new class of fluorescent labeling agents due to their attractive optical and chemical features including low toxicity, wide photoluminescence (PL) emission and high resistance to photobleaching. In this paper, an ionic-liquid-induced synthesis of Ce(1 - x)Tb(x)F(3) nanoparticle was investigated via utilizing a capillary microreactor. Ionic liquid-[bmim]BF(4) acts as both a fluoride source and stabilizing solvent during the reaction, which was shown to be a key factor that governs luminescence intensity of the obtained nanoparticles. The luminescent properties can be greatly improved by optimizing the volume percentage of [bmim]BF(4). Furthermore, the reaction temperature exerts an influence on the properties of the prepared samples. Experimental results show that the colloidal solutions of Tb(3+)-doped CeF(3) NCs exhibit the characteristic emission of Ce(3+) 5d-4f and Tb(3 + 5) D(4)-(7)F(J) (J = 6-3) transitions with (5)D(4)-(7)F(5) green emission at 542 nm as the strongest peak. The as-prepared samples are found dispersible in water with the quantum yield (in aqueous solution) as 12%, which indicates a potential application on biolabels, light-emitting diodes (LEDs) and redox luminescent switches.