Determination of Standard Molar Enthalpies of Formation of Complexes of Rare Earth Bromides with Glycine

ＤｅｔｅｒｍｉｎａｔｉｏｎｏｆＳｔａｎｄａｒｄＭｏｌａｒＥｎｔｈａｌｐｉｅｓｏｆＦｏｒｍａｔｉｏｎｏｆＣｏｍｐｌｅｘｅｓｏｆＲａｒｅＥａｒｔｈＢｒｏｍｉｄｅｓｗｉｔｈＧｌｙｃｉｎｅＳｕｎＴｏｎｇｓｈａｎ（孙同山），ＷａｎｇＦｅｎｇｌｉａｎ（王凤廉），...     

Determination of Crystal Structure of Britholite-Y

ＤｅｔｅｒｍｉｎａｔｉｏｎｏｆＣｒｙｓｔａｌＳｔｒｕｃｔｕｒｅｏｆＢｒｉｔｈｏｌｉｔｅ－ＹＺｈａｎｇＪｉａｎ－Ｈｏｎｇ；（张建洪）；ＦａｎｇＺｅ；（方泽）；ＬｉａｏＬｉ－Ｂｉｎｇ；（廖立兵）（ＣｈｉｎａＵｎｉｖｅｒｓｉｔｙｏｆＧｅｏｓｃｉｅｎｃｅｓ，...     

Standard Enthalpies of Formation of Solid Complexes of Lanthanide Nitrates with Alanine

Ｇｒｅａｔｉｎｔｅｒｅｓｔｈａｓｂｅｅｎａｒｏｕｓｅｄｉｎｔｈｅｓｔｕｄｙｏｆｃｏｍｐｌｅｘｅｓｏｆｒａｒｅｅａｒｔｈｓａｌｔｓｗｉｔｈａｍｉｎｏａｃｉｄｓｂｅｃａｕｓｅｒａｒｅｅａｒｔｈｉｏｎｓｐｏｓｓｅｓｓｓｏｍｅｓｐｅｃｉａｌｆｕｎｃｔｉｏｎｓｉｎｂｉｏｃｈｅｍｉｓｔｒｙ .Ｔｈｅｙｃａｎｂｅｕｓｅｄａｓａｐｒｏｂｅｔｏｌａｂｅｌｔｈｅｃａｌｃｉｕｍｉｏｎ .Ｍｏｒｅｏｖｅｒ,ａｍｉｎｏａｃｉｄｓａｒｅｔｈｅｓｔｒｕｃｔｕｒｅｕｎｉｔｏｆｐｒｏｔｅｉｎｓ .Ｇａｏａｎｄｃｏｗｏｒｋｅｒｓｒｅｃｅ…     

of tend

on transplant are as follows: autologous tendon, allogeneic tendon, artificial tendon and tissue engineered tendon. Recently, studies on allogeneic tendon are more and more favorable. In late 1980s, establishment and development of tissue engineering bring a new way for repairing de     

ARefined Model of Three-roller Elastoplastic Asym-metrical Pre-bending of Plate

The geometry of plate after edge pre-bending mode is compared with that after roll-bending mode and the relationship among edge pre-bending angle, pre-bending edge length, and cylindrical desired radius is presented for a three-roller plate bender with bottom rollers adjustable horizontally. The analytical moment-curvature model and springhaek model for pure bending are established, assuming that the stress-strain relationship of material is linear, and the material is in plain strain and yields according to Mises yield criterion. The mathematical model for three- roller edge pre-bending of plate is developed considering the effect of pre-bending edge length, bottom roller radius, friction between plate and roller, etc. The plate tensile test and plate bending test are done and the numerical results agree well with the test data. The results are shown graphically and analyzed in the following aspects： （1） the error between numerical results and test data of top roiler force; （2） the influence of bottom roller radius, relative curva- ture, and bending arc length on springback angle; （3） the relationship between springhack ratio and edge pre-ben- ding angle.     

Analysis of the Specific Features of Wear of the Working Rolls of the Finishing Group of Stands Under Conditions of the 1950 Mill at the Casting-Rolling Complex of the “VMZ” JSC

Metallurgist - We present the analysis of the mechanism of in-service wear of the working rolls of wide-band rolling mills on an example of a 1950 mill from the casting-rolling complex of the...     

Performance of Low Fluoride Dephosphorization Slag of Hot Metal

 The purpose of this study is decreasing content of CaF2 in dephosphorization slag. The dephosphorization effects with CaF2 replaced by B2O3 were investigated. The dephosphorization experiments were carried at 1450℃ in air atmosphere. The results show that the melting points and dephosphorization ratios change little when B2O3 replaced CaF2. The dephosphorization ratios which are all greater than 80% and melting points can meet the requirement of hot metal pretreatment. Because of the change of alkalinity caused by B2O3, the oxidation of slag increases with increasing of B2O3 contents. It is beneficial to pre-dephosphorization. As a result, for decreasing its pollution, CaF2 can be replaced by B2O3 to dispose fluoride-free pre-dephosphorization slag.     

Investigation of Crystallization Incorporation of Er-implanted Silicon

ＩｎｖｅｓｔｉｇａｔｉｏｎｏｆＣｒｙｓｔａｌｌｉｚａｔｉｏｎＩｎｃｏｒｐｏｒａｔｉｏｎｏｆＥｒ－ｉｍｐｌａｎｔｅｄＳｉｌｉｃｏｎＷａｎＹａ（万亚）；ＬｉＤａｉｑｉｎｇ（李岱青）（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＹａｎｔａｉＴｅａｃｈｅｒｓ...     

Effects of Electromagnetic Stirring on Solidification of Metal Foams

Metal foams are usually used as light structural/functional materials.The nucleation,evolution and the solidification behavior of the metal foams can be influenced by the stirring mode and the foaming parameters.In this paper,the effects of electromagnetic stirring on metal foaming process were investigated.Comparative tests were carried out and the optimized parameters of the stirring modes were discussed.The stirring effects of the spiral electromagnetic field are better than the travelling wave electromagnetic field.The effects of the spiral electromagnetic-mechanical combined stirring are better than the situations of the single electromagnetic stirring or the single mechanical stirring.     

Effect of Morphology of Instantaneous Inoculant on Inoculated Result of Melted Iron

In 192 2 ,AmericanMeehanappliedthefirstpatentforinoculatedcastiron .Nowtherearemorethan 10 0 0kindsofinoculantsintheworld .Thein oculationmeansthatsomematerialisputintomeltedirontocausesome physicalandchemicalchangeswhicharedifferentfromthosecausedbythealloyingelementinthecastiron .Intheearlydays ,themaincontentofinoculantwassilicon ,andsoonafterwardscalcium ,aluminium ,barium ,strontiumandmanga nese ,etcwereincluded .In 196 1,ceriumwasintro ducedintoinoculant .Nowtheinoculantsarewidelyappli…     

Microstructure and electrochemical characteristics of La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-x（V0.81Fe0.19）x hydrogen storage alloys

Microstructure and electrochemical characteristics of La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-x(V0.81Fe0.19)x hydrogen storage alloys were investigated. XRD indicated that La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-x(V0.81Fe0.19)x alloys consisted of a single phase with CaCu5-type structure, and the lattice parameter a and cell volume V increased with increasing x value. The maximum discharge capacity first increased from 319.0 (x=0) to 324.0 mAh/g (x=0.05), and then decreased to 307.0 mAh/g (x=0.20). The high-rate dischargeability at the discharge current density of 1200 mA/g first increased from 52.1% (x=0) to 59.1% (x=0.15), and then decreased to 55.4% (x=0.20). The hydrogen diffusion in the bulky alloy was responsible for the high-rate dischargeability. Cycling stability first increased with increasing x from 0 to 0.10 and then decreased when x increased to 0.20, which was resulted from the synthesized effect of the improvement of the pulverization resistance and the decrease of corrosion resistance.     

A study on hydrogen storage and electrochemical properties of La_（0.55）Pr_（0.05）Nd_（0.15）Mg_（0.25）Ni_（3.5） （Co_（0.5）Al_（0.5））_x （x=0.0, 0.1, 0.3, 0.5） alloys

The La0.55Pr0.05Nd0.15Mg0.25Ni3.5(Co0.5Al0.5)x(x=0.0, 0.1, 0.3, 0.5) alloys were prepared by magnetic levitation melting under an Ar atmosphere, and the effects of Co and Al on the hydrogen storage and electrochemical properties were systematically investigated by pressure composition isotherms, cyclic voltammetry, Tafel polarization and electrochemical impedance spectroscopy testing. The results showed that the alloy phases were mainly consisted of (La,Pr)(Ni,Co)5, LaMg2Ni9, (La,Nd)2Ni7 and LaNi3 phases, and the cell volumes of (La,Pr)(Ni,Co)5, LaMg2Ni9, (La,Nd)2Ni7 and LaNi3 phases expanded with Co and Al element added. The hydrogen storage capacity initially increased from 1.36 (x=0) to 1.47 wt.% (x=0.3) and then decreased to 1.22 wt.% (x=0.5). The discharge capacity retention and cycle stability of the alloy electrodes were improved with the increase of Co and Al contents. The La0.55Pr0.05Nd0.15Mg0.25Ni3.5(Co0.5Al0.5)0.3 alloy electrode possessed better electrochemical kinetic characteristic.     

Electrochemical properties of cobalt-free La0.80Mg0.20Ni2.85Al0.11M0.53 （M=Ni, Si, Cr, Cu, Fe） alloys

In order to investigate the effect of different B-site additions on phase structure and electrochemical properties of cobalt-free La-Mg-Ni based alloys, La0.80Mg0.20Ni2.85Al0.11M0.53 (M=Ni, Si, Cr, Cu, Fe) hydrogen storage alloys were prepared and studied systemati-cally. X-ray powder diffraction showed that the alloys consisted mainly of LaNi3 phase and LaNi5 phase except that Cr addition caused a minor Cr phase. Electrochemical testing indicated that alloys with additional Ni, Cr, Cu or Fe were activated within only 1-2 cycles, while that with Si addition needed 4 cycles. Adding Si, Cu and Fe increased cycling stability of La-Mg-Ni based alloys. However, maximum discharge capacity decreased from 362 mAh/g to 215 mAh/g in the order of Ni>Fe>Cu>Cr>Si. In addition, electrochemical kinetics of alloy electrodes was also researched by measuring high rate discharge ability (HRD), hydrogen diffusion coefficient (D) and limiting current density (IL).     

Study on structure and electrochemical properties of the （LaGdMg）Ni3.35-xCoxAl0.15（x=0-2.0） hydrogen storage alloys

Hydrogen storage alloys(LaGdMg)Ni3.35-xCoxAl0.15(x=0,0.1,0.3,0.5,1.0,1.5,2.0) were prepared by induction melting followed by annealing treatment in argon atmosphere.The effects of partly replacing Ni by Co element in(LaGdMg)Ni3.35Al0.15 on the phase structure and electrochemical properties of(LaGdMg)Ni3.35-xCoxAl0.15 alloys were investigated.Structure analysis showed that the alloys consisted of Ce2Ni7-type(Gd2Co7-type),CaCu5-type,Pr5Co19-type,PuNi3-type phase structure.The addition of Co element obviously reduced the contents of CaCu5-type phase and increased the contents of Ce2Ni7-type phase.However,Pr5Co19-type and CaCu5-type phase obviously increased with the high content of Co.Rietveld analysis showed that the c-axis lattice parameters and cell volumes of the component phases increased with increasing Co content.The electrochemical measurements showed that as the Co content increased,the maximum discharge capacity and the cyclic stability of the annealed alloys both first increased then decreased.The(LaGdMg)Ni3.05Co0.3Al0.15 alloy electrode exhibited the maximum discharge capacity(392.92 mAh/g),and the(LaGdMg)Ni1.85Co1.0Al0.15 alloy electrode showed the best cyclic stability(S100=96.1%).     

La0.8Mg0.2(Ni2.7Co0.6Al0.1Mn0.1)x贮氢合金的电化学性能分析

采用恒电位法、EIS分析及双电极系统对La0.8Mg0.2(Ni2.7Co0.6Al0.1Mn0.1)x(x=0.9～1.10)系列合金进行电化学性能分析。结果表明,x=1.05的合金具有较好的自放电性能(CR=97.3%),而x=1.10的合金有较高的电化学容量(369 mAh.g-1)。合金电极的电化学阻抗谱(EIS)表明,随着化学计量比x的增大,合金电极的电荷迁移电阻先减小后增大,动力学性能先增强后减弱。线性极化测试表明,随着化学计量比x的增大,合金电极表面的电化学反应速率先增大后减小。通过合金电极阳极电流对时间响应的半对数曲线计算的氢扩散系数D随着化学计量比x的增大先增大后降低,说明合金内部的氢扩散能力先增强后降低。     

Co含量对La0.55Pr0.05Nd0.15Mg0.25Ni3.5-xCoxAl0.25（x=0～0.4）储氢合金电极性能的影响

采用电磁感应悬浮炉制备La0.55Pr0.05Nd0.15Mg0.25Ni3.5-xCoxAl0.25(x=0,0.1,0.2,0.3,0.4)系列合金,研究Co含量对合金的相结构、吸放氢性能和电化学性能的影响。研究结果表明,该系列合金主要由LaNi5、Nd2Ni7相组成。当Co含量大于0.2时,合金中出现La2Ni7相。压强-吸氢量-温度(Pressure-Content-Temprature)测试显示在303 K温度下,合金具有良好的吸氢性能,当x=0.4时合金的最大吸氢量为1.29(质量分数,%)。电化学测试表明:随x值变化,合金电极的最大放电容量分别为340.0(x=0.0)、346.6(x=0.1)、370.0(x=0.2)、320.0(x=0.3)和346.6(mA.h)/g(x=0.4);随Co含量增加,合金电极容量保持率不断增加,高倍率放电性能先增加后减小,循环伏安曲线、氢在合金体中的扩散系数D共同反映了合金电极的动力学特性。     

(La_xNd_y)_(0.90)Mg_(0.10)Ni_(3.09)Mn_(0.12)Co_(0.60)Al_(0.13)贮氢合金自放电性能研究

为了提高La-Mg-Ni基贮氢合金的荷电保持率,本文研究了La/Nd比的变化对La-Mg-Ni基贮氢合金自放电性能的影响。随着Nd替代La量的增加,(LaxNdy)0.9Mg0.10Ni3.09Mn0.12Co0.60Al0.13(x/y=5,4,3,2,1)合金的荷电保持率先增大后减小,当x/y=4时,其荷电保持率达到最大值80.8%(318 K)。合金电极贮存后,FESEM-EDS和XRD分析表明,合金颗粒表面形成了Mg(OH)2和Nd(OH)3。P-C-T曲线和Tafel极化测试表明,随着Nd含量的增加,金属氢化物的稳定性呈现先增加后降低和腐蚀电流先减小后增大的规律。     

Structure and electrochemical hydrogen storage characteristics of Ce-Mg-Ni-based alloys synthesized by mechanical milling

The substituting Mg with Ni and milling as-cast alloy with Ni were adopted to obtain nanocrystalline/amorphous CeMgnNi+x wt.%Ni(x=100,200) alloys and promote the electrochemical hydrogen storage performances of CeMg_(12)-type alloys.Analyzing the structural features of the alloys provided a mechanism for ameliorating the electrochemical hydrogen storage properties.The electrochemical tests demonstrated that all the alloys just needed one cycle to be activated.Rising Ni proportion had an obvious role on charge-discharge reaction.The discharge capacities of the as-milled(60 h) alloys increased sharply from 182.0 mAh/gfor x=100 alloy to 1010.2 mAh/gfor x=200 alloy at current density of 60 mAh/g.Furthermore,milling time largely determined the performances of electrochemical reaction.The discharge capacity continued to grow along with prolonging milling time,while the cycle stability obviously decreased for x=100 alloy,and first declined and then augmented for the x=200 alloy with milling time extending.In addition,there was an optimal value with milling time varying for the high rate discharge abilities(HRD),which was 80.3%for x=100 alloys and 86.73%for x=200,respectively.     

La0.65RE0.10Mg0.25Ni3.5Si0.15(RE=La,Ce,Pr,Nd,Sm)储氢合金的电化学性能及EIS分析

通过感应熔炼制备La0.65RE0.10Mg0.25Ni3.55i0.15(RE =La,Ce,Pr,Nd,Sm)合金.采用X射线衍射方法分析了合金的相结构,研究了其电化学性能,并采用电化学阻抗谱分析了合金电极的放氢动力学特性.研究结果表明,合金是以LaNi5、LaNi3为主相的多相结构,同时合金中少量的Si元素与Mg和Ni元素形成了少量的Mg2 Si相和Ni2Si相.Ce,Pr,Nd,Sm部分替代La以后,合金的放电容量下降,Ce的替代使合金容量大幅度降低.对于本系列合金,La被其他稀土元素部分替代后,合金经过100次循环后的容量保持率略有下降,但除了Pr元素以外,变化值均较小.合金电极的电化学阻抗谱分析表明,中低频区的容抗弧半径依次为Ce ＞La＞ Nd ＞Sm ＞Pr,这表明采用Nd、Sm、Pr替代La后合金电极在碱液中放电过程电荷传递电阻Rct减小,即合金表面活性增加,但Ce替代却导致Ret急剧增大,这可能与Ce在碱液中易形成氧化物降低了合金的表面活性有关.     

Effect of Ni/（La＋Mg） Ratio on Structure and Electrochemical Performance of La-Mg-Ni Alloy System

As the alloy with the most suitable Ni/(La+ Mg) ratio has higher capacity and good cycle stability,theeffects of Ni/(La+Mg) ratios on the electrochemical performances of the La0.80 Mg0.20 Nix (x= 3.5 to 5.0) alloys have been investigated to find the most suitable Ni/(La+ Mg) ratio.The results of XRD and SEM observations show that the phase composition of the alloys varies with different Ni/(La+Mg) ratios.When Ni/(La+Mg) is notmore than 4.25,all the alloys contain LaNi5 and (La,Mg)2Ni7 phases,in addition,the LaMg and (La,Mg)Ni3 phases exist in the x=3.5 and 3.75 alloys,respectively.The LaMg2Ni9 phase exists in the x=4.25 alloy.There are the LaNi5 and LaMg2 Ni9 phases in the x= 4.5,4.75,and 5.0 alloys.The phase abundance and cell volume change with different Ni content.When the Ni/(La+Mg) ratio is not more than 4.25,the alloys possess excellent activation capability,however,the activation capabilities of the alloys decrease with a further increase in the Ni/(La+Mg)ratio.With increasing the Ni/(La+ Mg) ratio,the maximum discharge capacities,the medium voltages,and the cycle stabilities of the alloys first increase and then decrease.When the Ni/(La+Mg) ratio is 3.75,the corresponding alloyhas the maximum discharge capacity among all the alloys.However,the cycle stability of the Ni/(La+ Mg)= 4.0 alloy is better than that of the others.