Synthesis and photoluminescence properties of Eu(pzc)3(phen) and Eu(mpzc)3(phen)

Novel europium(III) complexes, (2-pyrazinecarboxylato)(phenanthroline) europium(III) [Eu(pzc)₃(phen)] and (5-methyl-2-pyrazinecarboxylato) (phenanthroline)europium(III) [Eu(mpzc)₃(phen)] have been designed and synthesized. These complexes were characterized by FT-IR, UV-Vis, and X-ray photoelectron spectroscopy. Photoluminescence (PL) studies showed that the two complexes emitted remarkably red luminescence. When powder samples of Eu(pzc)₃(phen) and Eu(mpzc)₃(phen) were examined using time-resolved spectroscopic analysis, the luminescence lifetimes were found to be 1.05 and 2.36 ms, respectively. Thermogravimetric analysis showed that the europium complexes possessed good thermal stability up to 345–350 °C.     

Mg61Cu28Gd11和(Mg0.61Cu0.28Gd0.11)99.5Sb0.5非晶合金的晶化动力学和腐蚀行为（英文）

研究0.5%(摩尔分数)Sb的引入对Mg61Cu28Gd11块体非晶合金性能的影响。利用差热扫描量热仪测试样品的晶化动力学。结果表明:在等时加热的过程中,非晶合金的玻璃转变温度、起始晶化和峰值晶化温度都表现出对加热速率强的依赖性。基于Oawza方法可以确定非晶合金的起始晶化和峰值晶化激活能。Vogel-Fulcher-Tamman公式分析表明:含Sb元素的非晶合金具有更高的强度系数和更长的延迟时间。采用电化学极化和失重测试方法研究2种玻璃合金的腐蚀行为。与基体非晶合金相比,添加微量Sb降低了非晶合金的在含Cl-的碱性溶液中的钝化电流密度和腐蚀速率,表现出相比基体合金更为优越的耐蚀性。最后基于"点缺陷模型"进一步分析微量Sb元素对基体合金耐蚀性能的影响机理。     

机械合金化法制备的Mn15Bi34Te51和La15Bi34Te51热电材料

用机械合金化法制备了Mn15Bi34Te51和La15Bi34Te51合金，XRD分析表明Mn15Bi34Te51和La15Bi34Te51分别在真空球磨150h和100h后实现合金化，La15Bi34Te51在真空球磨150h后形成了纳米结构的合金，镧原子的加入有助于Bi2Te3基合金的晶粒细化及非晶化。对La15Bi34Te51合金的XRD结构分析表明镧原子有可能进入了Bi2Te3层状结构的Te-Te原子层间。La15Bi34Te51合金Seebeck系数的测量表明当晶粒尺寸减小到纳米尺寸时，载流子散射机制有可能发生改变，导致了Seebeck系数的大幅上升。     

Formation and Structural Evolution of Fe_(72.5)B_(15.6)Si_(7.8)Nb_(1.7)Zr_(1.7)Cu_(0.7) Nanocrystalline Alloy

A 2.5-mm Fe_(72.5)B_(15.6)Si_(7.8)Nb_(1.7)Zr_(1.7)Cu_(0.7) glassy rod was successfully fabricated using copper mold casting.The introduction of Cu resulted in the formation of large quantities of a-Fe nanoparticles embedded in the glassy matrix after isothermal annealing.The Fe_(72.5)B_(15.6)Si_(7.8)Nb_(1.7)Zr_(1.7)Cu_(0.7) nanocrystalline alloy exhibited high saturation magnetization(～1.26 T) and a low coercive force(～0.8 A/m) after annealing at 833 K for 15 min due to the precipitation of ～15-nm-sized a-Fe nanoparticles in the glassy matrix.The structural evolution of the FeBSiNbZrCu amorphous alloy during the annealing process was discussed using a dual-cluster model.     

The Nb-Rb (Niobium-Rubidium) and Rb-V (Rubidium-Vanadium) systems

This work was performed in the Ames Laboratory, which is operated by Iowa State University for the U.S. Department of Energy and was supported by Department of Energy funds through the Joint Program on Critical Compilation of Physical and Chemical Data coordinated through the Office of Standard Reference Data, National Institute of Standards and Technology. Literature searched through 1984. Professor Smith is ASM/NIST Data Program Category Editor for binary vanadium alloys and Co-Category Editor for binary niobium alloys.     

Ti_(0.44)Al_(0.56)N和Cr_(0.42)Al_(0.58)N涂层的结构与热性能研究

TiAlN和CrAlN涂层是目前切削刀具应用最为广泛的涂层材料。本研究借助阴极弧蒸发技术在低合金钢、钨片和Al2O3刚玉片上制备了Al含量接近的Ti_(0.44)Al_(0.56)N和Cr_(0.42)Al_(0.58)N涂层,采用扫描量热仪(DSC)、扫描电子显微镜(SEM)、X射线能量色散谱仪(EDX)、X射线衍射仪(XRD)和纳米压痕仪对比研究其结构、力学性能、热稳定性及抗氧化性能。结果表明:Ti_(0.44)Al_(0.56)N和Cr_(0.42)Al_(0.58)N涂层均为单相面心立方结构,其硬度分别为30.1±0.4 GPa和30.2±0.7 GPa;Ti_(0.44)Al_(0.56)N涂层在退火过程中会产生时效硬化效应而呈现更好的热稳定性,900℃时为32.4±0.7 GPa;在1 100℃退火后,Ti_(0.44)Al_(0.56)N和Cr_(0.42)Al_(0.58)N涂层的硬度分别降至27.8±0.8 GPa和22.6±0.4 GPa;Cr_(0.42)Al_(0.58)N涂层则具有更优异的抗氧化性能,Cr_(0.42)Al_(0.58)N涂层在1 000℃氧化10 h后,氧化层的厚度仅为0.17μm,而Ti_(0.44)Al_(0.56)N涂层在900℃氧化10 h后已完全氧化。     

氢化脱氢钕铁硼微观组织结构的变化

采用SEM和XRD对Nd13Fe81.5B5.5合金氢化-歧化-脱氢过程中相结构和组织形貌的变化进行了观测分析，结果表明：非受热的Nd13Fe81.5B5.5合金的吸氢只能在富钕相的品界上进行，吸氢的过程伴随着热量的释放。加热后的Nd13Fe81.5B5.5合金吸氢不仪沿着Nd13Fe81.5B5.5富钕相品界进行，而且也能在其品格内进行。合金吸氢后牛成物丰相为NdH2.9和α-Fe，还有微量的Fe2B和Fe2Nd，吸氢的过程伴随着大量热的释放，Nd13Fe81.5B5.5合金的吸氢温度为700℃，在730℃～800℃的范围内脱氢，在此工艺条件下，能获得高质量的氢化物。     

混合稀土贮氢合金(Ml)_x(Ni_(3.8)Co_(0.75)Mn_(0.4)Ti_(0.05))相结构与性能的研究

对 (Ml) x(Ni3.8Co0 .75Mn Ti0 .0 5)合金 (x =0 .90～ 1 .1 0 )的相结构 ,热力学性能及合金电极的充放电性能进行了研究。结果表明 :在 x <1 .0 0的成分范围内 ,合金保持单一的 La Ni5相 ;当 x≥ 1 .0 0时 ,合金中析出多种第二相 ,且总量随 x的增加而增多。随着 x的增加 ,合金的晶胞体积及氢化物生成焓 (-ΔH )增大 ,吸放氢平台压力降低 ,宽度增加。合金的最大放电容量在 x =1 .0 0 时达到最大值 (30 7.7m Ah/g)。x <1 .0 0 合金的循环稳定性优于 x≥ 1 .0 0 合金。     

Corrosion behavior of Cr electrodeposited from Cr(VI) and Cr(III)-baths using direct (DCD) and pulse electrodeposition (PED) techniques

A comparison was made between the electrochemical corrosion behaviors of chromium deposited from hexavalent [Cr(VI)] and trivalent [Cr(III)] chromium baths using direct current (DCD) and pulse electro deposited (PED) techniques. Chromium coatings were deposited on mild-steel (MS) substrate. The corrosion behavior of both DCD and PED chromium from Cr(VI) and Cr(III)-baths in 3.5%NaCl solution was studied using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results indicated that PED chromium from Cr(VI) and Cr(III)-baths have higher charge-transfer resistance R_ct and very low I_corr than that of DCD chromium on mild-steel substrate.     

Microstructure and electrochemical properties of La_(0.8-x)MM_xMg_(0.2)Ni_(3.1)Co_(0.3)Al_(0.1)(x=0,0.1,0.2,0.3)alloys

The present study aims to improve electrochemical properties of the La-Mg-Ni-based hydrogen storage alloys through partial substitution for La by mischmetal(MM).The La_(0.8-x)MM_xMg_(0.2)Ni_(3.1)Co_(0.3)Al_(0.1)(x=0,0.1,0.2,0.3)alloys were prepared by inductive melting,and their phase structures and electrochemical properties were studied by X-ray diffraction(XRD),scanning electron microscope(SEM),energy-dispersive X-ray spectrometry(EDX)and electrochemical tests.Results show that the alloys mainly consist of La_2Ni_7-type phase,La_5Ni_(19)-type phase,LaNi_5-type phase and LaNi_3-type phase.The addition of MM does not change the phase compositions,while it leads to more uniform phase distribution and obviously promotes the formation of La_2Ni_7-type phase which possesses favorable electrochemical properties.Electrochemical studies indicate that the substitution for La by MM could effectively improve the high rate dischargeability(HRD)of the alloy electrode,and the optimal value of HRD_(1500)(HRD at 1500 mA·g~(-1))increases from 40.63%(x=0)to 60.55%(x=0.3).Although the activation properties of the alloy electrodes keep almost unchanged,both the maximum discharge capacity(C_(max))and the cycling stability are significantly improved by MM addition.     

Electric transport mechanism and magnetoresistance of La_(0.80)Sr_(0.15)Ag_(0.05)MnO_3/x(CuO)

The samples of La0.80Sr0.15Ag0.05 Mn O3/x(Cu O)(x = 0, 0.05, 0.10, 0.15, 0.20) were prepared by the solid-state reaction method, and the structure of the samples was detected by X-ray diffraction(XRD), scanning electron microscope(SEM) equipped with energy dispersive spectroscopy(EDS), electric transport mechanism, and magnetoresistance enhancement, and the temperature stability of magnetoresistance of the samples was studied through resistivity–temperature(q-T) curves, q-T fitted curves, and magnetoresistance–temperature(MR-T) curves.The results indicate that q-T data can be fitted by the formula q = q0 AT2 very well, and the electric transport mechanism of all the samples in metal-like area is the scattering of single magneton upon spin electron; the magnetoresistance of composite samples is far larger than that of the original material, and the MR peak value of the sample with x = 0.20 is nearly 4 times as large as that of the sample with x = 0; composite samples have comparatively good temperature stability of magnetoresistance in the temperature range of 200–260 K, and the magnetoresistance of the sample with x = 0.15 almost does not change with temperature and keeps at(5.03 ± 0.20) % in the temperature range of 210–260 K.     

Hydrogen storage properties of as-cast and annealed low-Co La_(1.8)Ti_(0.2)MgNi_(8.9)Co_(0.1) alloys

Low-Co La_(1.8)Ti_(0.2)MgNi_(8.9)Co_(0.1) alloys were prepared by magnetic levitation melting followed by annealing treatment. The effect of annealing on the hydrogen storage properties of the alloys was investigated systematically by X-ray diffraction(XRD), pressure-composition isotherm(PCI), and electrochemical measurements. The results show that all samples contain LaNi_5 and LaMg_2Ni_9 phases. LaCo_5 phase appears at 1,000 ℃. The enthalpy change of all hydrides is close to -30.6kJ·mol~(-1)H_2 of LaNi_5 compound. Annealing not only increases hydrogen capacity and improves cycling stability but also decreases plateau pressure at 800 and 900 ℃. After annealing, the contraction of cell volume and the increase of hydride stability cause the high rate dischargeability to reduce slightly. The optimum alloy is found to be one annealed at 900 ℃, with its hydrogen capacity reaching up to 1.53 wt%, and discharge capacity remaining 225.1mAh·g~(-1) after 140 charge–discharge cycles.     

Lithium–oxygen (air) batteries (state-of-the-art and perspectives)

Functional bases of power sources of Li–O₂ type have been considered. Particular attention has been devoted to the Li–O₂ system with liquid aprotic electrolyte as the most promising version of a rechargeable Li–O₂ cell. The current status of research on the design of the principal components of Li–O₂ battery represented by catalytically active and patterned materials, as well as binders for the formation of positive electrode, solvents and electrolytes, and separation membranes has been characterized. Insights into the mechanisms of the reactions that occur during discharge and recharge have been challenged and the factors that restrict cycling and discharge capacity of Li–O₂ cell have been considered. Top-priority scientific and technological problems of the design of Li–O₂ battery, which is competitive with respect to lithium-ion batteries, have been stated.     

固溶处理对(Mg_(96.5)Zn_(1.5)Er_2)_(99.82)Zr_(0.18)合金组织和硬度的影响

采用光学金相显微镜、SEM、EBSD、DTA分析以及硬度等试验手段,研究了固溶处理对(Mg_(96.5)Zn_(1.5)Er_2)_(99.82)Zr_(0.18)合金组织和力学性能的影响。结果表明,合金铸态及热处理态的微观组织均由α-Mg、X相和(Mg,Zn)_xEr相组成,对铸态的(Mg_(96.5)Zn_(1.5)Er_2)_(99.82)Zr_(0.18)合金进行固溶处理后,(Mg,Zn)_xEr相转变成弥散分布的X相。晶粒尺寸随着固溶时间和温度的增加而变大。与铸态相比,合金热处理后的硬度没有发生太大变化。     

Crystallization Behavior of Metallic GlassCo_（65．1）Fe_（4．7）Ni_（4．6）Si_（10．2）B_（15．4）

ＣｒｙｓｔａｌｌｉｚａｔｉｏｎＢｅｈａｖｉｏｒｏｆＭｅｔａｌｌｉｃＧｌａｓｓＣｏ＿（６５．１）Ｆｅ＿（４．７）Ｎｉ＿（４．６）Ｓｉ＿（１０．２）Ｂ＿（１５．４）ＬｉＺｏｎｇｑｕａｎ；ＱｉｎＹｏｎｇａｎｄＨｅＹｉｚｈｅｎ（李宗全），（秦勇）（何怡贞）（...     

Ti_3Si_(0.6)Al_(0.6)C_(1.98)陶瓷的制备与性能研究

采用原位热压工艺制备了高纯Ti_3Si_0.6Al_0.6C_1.98陶瓷,并测试了性能.以单质的Ti、Si、Al和石墨粉为原料,摩尔比Ti:Si:Al:C=3:0.6:0.6:1.98,在1500 ℃,30 MPa压力下保温1 h,高纯Ar气保护,制备试样的主要物相为Ti_3Si_0.6Al_0.6C_1.98.制备的Ti_3Si_0.6Al_0.6C_1.98陶瓷的密度为(4.43±0.23) g/cm~3,电阻率为(0.31±0.01)μΩ·m,抗弯强度为(245.46±22.04) MPa,维氏硬度为(2.91±0.32) GPa, 断裂韧性为(5.63±0.39) MPa·m~(1/2).Ti_3Si_0.6Al_0.6C_1.98陶瓷中晶粒以板状晶为主,晶粒层状结构明显,断口形貌显示主要为穿晶断裂,晶粒的分层断裂、微裂纹的偏转桥接及滑移使材料具有独特的压痕特征.     

Iodine-doped bridged phthalocyaninatoiron(II) and -ruthenium(II) compounds

Phthalocyaninatoiron(II) and -ruthenium(II) compounds [R_mPcML]n(M = Fe, Ru) with different bridging ligands L = 1,4-diisocyanobenzene (1,4-dib), 1,4-dicyanobenzene (dcb), 4,4′-diisocyanobiphenyl (dibph) and 4,4′-bipyridylacetylene (bpyac), 2,3,5,6-tetramethyldiisocyanobenzene (Me₄dib), 2,3,5,6-tetrachlorodiisocyanobenzene (Cl₄dib) and 1,3-diisocyanobenzene (1,3-dib) are reacted with iodine using different doping procedures. Except for the perchlorocomplexes 8a and 17a, stable compounds [R_mPcMLI_y]_n are formed, which were characterized by thermogravimetric measurements, infrared, resonance-Raman and ⁵⁷Fe-Mössbauer spectroscopy. An increasing dopant level of iodine causes a continuous increase in electronic conductivity of the compounds [R_mPcMLI_y]_n, which, in spite of their comparatively large inter-ring distances, exhibit room-temperature powder conductivities in the range σ_RT = 10⁻² -10⁻¹ S/cm.     

RESISTIVITY ANOMALY IN METALLIC GLASSES(Fe_(1-x)Co_x)_(78)Si_(9.5)B_(12.5)

用四端引线法测量了4.2K到室温的非晶态(Fe_(1-x)Co_x)_(18)Si_(9.5)B_(12.5)(x=0—1.0)合金的电阻率。结果表明,x=0—1.0的所有样品都出现了电阻率与温度关系的极小值。电阻率极小值温度T_(min)随Co含量x的增加而增加,在x=0.9时出现极大值。在T_(min)温度以下,电阻率与温度关系符合-lnT规律。x=0.5—1.0的样品,电阻率与-lnT关系出现两个斜率。在T_(min)温度以上,约100K以下电阻率符合T~2规律,在约100K以上电阻率则按T~(3/2)规律变化。实验结果表明,约在9.5K和100K温区,电阻率与温度关系可近似表达为:ρ/ρ_(min)=ρ_0+AlnT+BT~2。显现类Kondo型电阻极小。电阻率的T~2关系来源于电子-声子散射。     

双(二甲氧基苯基膦)二氯化钯(Ⅱ)的合成及化学结构表征

以氯亚钯酸钠、双甲氧基苯基膦酸盐为起始原料,通过配位取代反应合成了大配体C-C偶联催化剂双(二甲氧基苯基磷)二氯化钯(Ⅱ)(Pd Cl2[P(OMe)2Ph]2)。优化的一步合成条件为:在氩气保护下,向双甲氧基苯基膦酸盐的四氢呋喃溶液中滴加0.5倍摩尔分数的氯亚钯酸钠水溶液,50℃反应得到配合物,产率为96.5%。采用核磁共振(1H NMR)及单晶X射线衍射(XRD)对产物化学结构进行测定和解析。1H NMR显示,2个苯环及4个甲氧基上的氢核信号的化学位移、峰面积与目标化合物对应一致;单晶XRD确定其晶体为单斜晶系空间群为C2/c,获得了相应的键长和键角参数。     

STRUCTURAL RELAXATION OF AMORPHOUS ALLOYS Fe_(77.8)Si_(7.5)B_(14.7) AND Fe_(78.5)Si_(8.9)B_(12.6)

<正> 本文用Mossbauer技术结合DTA和电阻分析,对两种非晶态合金(Ⅰ)Fe_(77.8)Si_(7.5)B_(14.7)和(Ⅱ)Fe_(78.5)Si_(8.9)B_(12.6)的结构弛豫进行了研究。 Ⅰ和Ⅱ两种非晶态合金的DTA曲线如图1,晶化开始温度分别为530和500℃,晶化前均出现较长的放热峰,预示其结构弛豫过程中可能发生某种结构变化。