A new rhombohedral phase and its 48 variants inβtitanium alloy

A new rhombohedral phase(termed R′)in a solution-aging-treated titanium alloy(Ti-4.5Al-6.5Mo-2Cr-2Nb-1V-1Sn-1Zr,wt.%)was identified.Its accurate Bravais lattice parameters were determined by a novel unit cell reconstruction method based on conventional selected-area electron diffraction(SAED)technique.The orientation relationship between R'phase and BCC phase was revealed.The results show that the R′phase is found to have 48crystallographically equivalent variants,resulting in rather complicated SAED patterns with high-order reflections.A series of in-situ SAED patterns were taken along both low-and high-index zone axes,and all weak and strong reflections arising from the 48 variants were properly explained and directly assigned with self-consistent Miller indices,confirming the presence of the rhombohedral phase.Additionally,some criteria were also proposed for evaluating the indexed results,which together with the Bravais lattice reconstruction method shed light on the microstructure characterization of even unknown phases in other alloys.

Corrosion behavior of 2A97 Al-Cu-Li alloys in different thermomechanical conditions by quasi-in-situ analysis

As a promising material in the aircraft industry,2A97 Al-Cu-Li alloy exhibits high corrosion susceptibility that may limit its application.In the present work,to illustrate the influences of precipitate and grain-stored energy on localized corrosion evolution in 2A97 Al-Cu-Li alloy,cold working and artificial aging were carried out to produce 2A97 Al-Cu-Li alloys under different thermomechanical conditions.Quasi-in-situ analysis,traditional immersion test and electrochemical measurement were then conducted to examine the corrosion behavior of 2A97 alloys.It is revealed that precipitate significantly affects Cu enrichment at corrosion fronts,which determines corrosion susceptibility of alloys,whereas grain-stored energy distribution is closely associated with localized corrosion propagation.It is also indicated that quasi-in-situ analysis exhibits a consistent corrosion evolution with traditional immersion tests,which is regarded as a proper method to explore localized corrosion mechanisms by providing local microstructural information with enhanced time and spatial resolutions.

金天格胶囊治疗原发性骨质疏松症前瞻性多中心随机双盲对照临床试验

目的评价金天格胶囊(主要成分为人工虎骨粉)治疗原发性骨质疏松症的临床疗效和安全性。方法采用前瞻性分层区组随机方法、双盲双模拟、阳性药平行对照临床研究方法,纳入11家医院471例原发性骨质疏松受试者,以3∶1比例随机分配至试验组和对照组,其中试验组356例,对照组115例。试验组口服金天格胶囊1.2 g/次,3次/d,骨疏康胶囊模拟剂1.28 g/次,2次/d;对照组口服金天格胶囊模拟剂1.2 g/次,3次/d,骨疏康胶囊1.28 g/次,2次/d。两组用药疗程均为24周,干预48周电话随访。干预12周和24周分别评价中医证候积分,以其作为主要结局指标并评价临床疗效;以疼痛VAS评分、单项症状评分和骨密度指改善情况作为次要结局指标。安全性评价包括试验期间骨折发生率,血常规、尿常规、便常规、肝肾功能、心电图等安生性指标。结果(1)试验组12周的总有效率为64.61%(230/356),高于对照组的总有效率50.44%(58/115),差异有统计学意义(χ^(2)=11.580,P=0.000);试验组24周的总有效率为84.55%(301/356),高于对照组的总有效率71.30%(82/115),差异有统计学意义(χ^(2)=13.114,P=0.000);(2)两组24周的中医症状积分均较治疗前降低,差异有统计学意义(W=-26974.5,2775.00;P=0.000,0.000);试验组24周中医症状积分较基线下降的差值大于对照组的差值,差异有统计学意义(Z=2.656,P=0.008);(3)试验组24周腰背疼痛、腰膝酸软无力症状改善优于对照组(χ^(2)=9.940,χ^(2)=10.004;P=0.002,P=0.002),两组24周下肢抽筋、步履艰难和持重困难症状改善差异无统计学意义(χ^(2)=1.501,χ^(2)=3.035,χ^(2)=0.619;P=0.221,P=0.082,P=0.432);(4)试验组24周疼痛VAS评分明显低于对照组,差异有统计学意义(Z=2.644,P=0.008);(5)试验组24周骨密度改善的总有效率为91.98%(298/324),高于对照组的总有效率75.23%(82/109),差异有统计学意义(χ^(2)=17.020,P=0.000);试验组24周腰椎L2、腰椎L3、腰椎L4、腰椎L2-4骨密度较基线提高值明显高于对照组,差异有统计学意义(Z=-2.139,Z=-3.161,Z=-2.157,Z=-3.562;P=0.032,P=0.002,P=0.031,P=0.000),两组24周股骨颈(左)、股骨颈(右)骨密度较基线提高值无统计学意义(Z=-0.131,Z=-0.419;P=0.896,P=0.675);(6)两组不良反应发生率差异无统计学意义(P>0.05),两组患者用药及随访期间均未出现严重不良事件、无骨折情况发生。结论金天格胶囊能改善原发性骨质疏松患者中医证候总体疗效,尤其在改善腰背疼痛、腰膝酸软无力症状方面具有优势,同时能减轻疼痛程度,增加骨密度,并且安全性较好。

Price linkage between Chinese and international nonferrous metals commodity markets based on VAR-DCC-GARCH models

Using VAR-DCC-GARCH model,the literature on commodity price was extended by exploring the co-movement between Chinese nonferrous metal prices and global nonferrous metal prices represented by the nonferrous metal prices from London Metal Exchange(LME).The results show that LME nonferrous metals prices still have a greater impact on Chinese nonferrous metals prices.However,the impact of Chinese nonferrous metals prices on LME nonferrous metals prices is still weak except for lead price.The co-movement of nonferrous metal prices between LME and China presents hysteretic nature,and it lasts for 7-8trading days.Furthermore,the co-movement between LME nonferrous metals prices and Chinese nonferrous metals prices has the characteristics of time-varying,and the correlation of lead prices between LME and China is the more stable than all other nonferrous metals prices.

Applications of nonferrous metal price volatility to prediction of China's stock market

The aim of the present work is to examine whether the price volatility of nonferrous metal futures can be used to predict the aggregate stock market returns in China. During a sample period from January of 2004 to December of 2011, empirical results show that the price volatility of basic nonferrous metals is a good predictor of value-weighted stock portfolio at various horizons in both in-sample and out-of-sample regressions. The predictive power of metal copper volatility is greater than that of aluminum. The results are robust to alternative measurements of variables and econometric approaches. After controlling several well-known macro pricing variables, the predictive power of copper volatility declines but remains statistically significant. Since the predictability exists only during our sample period, we conjecture that the stock market predictability by metal price volatility is partly driven by commodity financialization.

Dynamic interacting relationships among international oil prices, macroeconomic variables and precious metal prices

From the perspective of long-term and short-term, the methods of TY causality test, generalized impulse response function, variance decomposition were used to investigate the impacts of international oil prices and macroeconomic variables on Chinese gold, silver and platinum prices, but also the feedback effects of Chinese precious metal prices under this impact. The results show that international oil prices play an important role in precious metal price variation both in long-term and short-term, and exchange rate only has an effect in short-term, while interest rate is ineffective in predicting precious metal prices. In addition, precious metal prices have some feedback effects on international oil prices and interest rate in short-term.

Numerical analysis of coupled finite element with element-free Galerkin in sheet flexible-die forming

A numerical method for coupled deformation between sheet metal and flexible-die was proposed. Based on the updated Lagrangian （UL） formulation, the elastoplastic deformation of sheet metal was analyzed with finite element method （FEM） and the bulk deformation of flexible-die was analyzed with element-free Galerkin method （EFGM）. The frictional contact between sheet metal and flexible-die was treated by the penalty function method. The sheet elastic flexible-die bulging process was analyzed with the FEM-EFGM program for coupled deformation between sheet metal and bulk flexible-die, called CDSB-FEM-EFGM for short. Compared with finite element code DEFORM-2D and experiment results, the CDSB-FEM-EFGM program is feasible. This method provides a suitable numerical method to analyze sheet flexible-die forming.

Structural changes and volatility correlation in nonferrous metal market

The GARCH and DCC-GARCH models are used to study the volatility aggregation and dynamic relevance of China’s three kinds of nonferrous metals （copper, aluminum and zinc） pricesincorporating structural changes. The results show that copper, aluminum and zinc returns have many structure breaks points, and nonferrous metals have the greatvolatilityrisk during financial crisis. From the resultsof GARCH with and without structural changes,it isfoundthat the volatility clustering of single nonferrous metal is overvalued when ignoring the structural mutation, and the return of aluminum isthe most overvalued, indicating that aluminum market is more susceptible to external shock.Furthermore,it is also foundthatdynamic volatility correlation exists in the three prices of nonferrous metals, and the structural changes have no significant effect on the volatility correlation of thethree nonferrous metals.

Precipitation hardening behavior of dilute binary Al-Yb alloy

The precipitation hardening behavior in dilute Al-Yb alloys upon annealing at different temperatures was investigated to shed light on the mechanism of micro-alloying element in aluminum alloys. When aging at different temperatures, the samples showed their corresponding peak hardness in the range of 400-416 MPa due to the precipitation of Al3Yb with L 12 crystal structure. The coarsening kinetics of the Al3Yb precipitates obeyed the LSW theory, which indicated that the coarsening process was controlled by the diffusion of Yb. The coherence between Al3Yb particles and matrix was maintained until the particle size reached 11 nm. When the particle size increased to about 2 nm, the shearing mechanism started to change to Orowan mechanism.

High Pressure Phase Stability of Ti with Self-consistent ab initio Lattice Dynamics Approach

The traditional quasiharmonic approximation cannot predict the phase diagram of Ti accu- rately, due to the well-known soften phonon modes of the β-Ti. By means of self-consistent ab initio lattice dynamics （SCAILD） method, in which the effects of phonon-phonon in- teractions are considered, the phonon dispersion relations at finite temperature for Ti are calculated. From the phonon dispersions, we extrapolat the acoustic velocities and harmonic elastic constants. The dynamical stable regions and phase diagram of Ti are also predicted successfully. The results show that SCAILD method can be designed to work for strongly anharmonic systems where the QHA fails.

故乡的竹林

记忆中．故乡最美的要数老屋边的一片竹林。村子三面是山。竹林便藏在一面山的底下。挨挨挤挤直到村子的出口处。

Carbon supported IrM(M= Fe,Ni,Co) alloy nanoparticles for the catalysis of hydrogen oxidation in acidic and alkaline medium

We studied the alloying effect in lr-based alloys on the catalysis of the hydrogen oxidation reaction （HOP,） in both acidic and alkaline medium. IrFe, lrNi and IrCo alloy catalysts with nanoparticle size of 〈S nm were obtained by our solvent-vaporization plus hydrogen reduction method. The second metal played an important role in tuning the crystal structure and surface electronic structure of the Ir-based alloy catalyst. Among the lrFe, IrCo and lrNi alloy catalysts, Ni induced a mid-sized contrac- tion of the lr lattice, and gave the best HOR activity in both acidic and alkaline medium. In acidic medium, the weakening of the Ir-Had interaction caused by the electronic effect of M （M = Fe, Ni, Co） alloying is responsible for the enhancement of HOR activity. The oxophilic effect of the catalytic metal surface, which affects OHad adsorption and desorption and surface Had coverage, has a large impact on the HOR activity in the case of alkaline medium,

金城集团新品迭出

继今年3月份金城铃木公司推出JC125-17C、GF125等五款新车型之后,8月18日,金城集团再度推出三款新车,JC125T-10“金王子”、JC125T-8“金格格”两款踏板车和JC125-17A“风啸”骑式车,吸引了全国各地摩托车经销商的广泛关注。 JC125T-10“金王子”和JC125T-8“金格格”是金城集团具有自主知识产权的新一代产品,它们做工精细,刚柔并济,代表着金城的形象和实力。

Alloy gene Gibbs energy partition function and equilibrium holographic network phase diagrams of AuCu_3-type sublattice system

Taking AuCu3-type sublattice system as an example, three discoveries have been presented: First, the third barrier hindering the progress in metal materials science is that researchers have got used to recognizing experimental phenomena of alloy phase transitions during extremely slow variation in temperature by equilibrium thinking mode and then taking erroneous knowledge of experimental phenomena as selected information for establishing Gibbs energy function and so-called equilibrium phase diagram. Second, the equilibrium holographic network phase diagrams of AuCu3-type sublattice system may be used to describe systematic correlativity of the composition?temperature-dependent alloy gene arranging structures and complete thermodynamic properties, and to be a standard for studying experimental subequilibrium order-disorder transition. Third, the equilibrium transition of each alloy is a homogeneous single-phase rather than a heterogeneous two-phase, and there exists a single-phase boundary curve without two-phase region of the ordered and disordered phases; the composition and temperature of the top point on the phase-boundary curve are far away from the ones of the critical point of the AuCu3 compound.

Alloy gene Gibbs energy partition function and equilibrium holographic network phase diagrams of Au_3Cu-type sublattice system

Taking Au3Cu-type sublattice system as an example, three discoveries have been presented. First, the fourth barrier to hinder the progress of metal materials science is that today’s researchers do not understand that the Gibbs energy function of an alloy phase should be derived from Gibbs energy partition function constructed of alloy gene sequence and their Gibbs energy sequence. Second, the six rules for establishing alloy gene Gibbs energy partition function have been discovered, and it has been specially proved that the probabilities of structure units occupied at the Gibbs energy levels in the degeneracy factor for calculating configuration entropy should be degenerated as ones of component atoms occupied at the lattice points. Third, the main characteristics unexpected by today’s researchers are as follows. There exists a single-phase boundary curve without two-phase region coexisting by the ordered and disordered phases. The composition and temperature of the top point on the phase-boundary curve are far away from those of the critical point of the Au3Cu compound; At 0 K, the composition of the lowest point on the composition-dependent Gibbs energy curve is notably deviated from that of the Au3Cu compounds. The theoretical limit composition range of long range ordered Au3Cu-type alloys is determined by the first jumping order degree.

Comparison between Sequential Gaussian Simulation and Kriging Interpolation on Soil Heavy Metal Pollution

[Objective] This study was to explore the difference of kriging interpolation and sequential Gaussian simulation on analyzing soil heavy metal pollution with a view to provide references for analyzing the heavy metal pollution of soil. [Method] The sampling data of soil copper from a county of Liaocheng, Shandong Province was set as the study objective. Kriging interpolation and sequential Gaussian simu- lation were used to simulate the spatial distribution of soil copper. And 30 sampling points were selected as the cross-validation data set to compare the two interpola- tion methods. [Result] Kriging method and Gaussian sequential simulation have their own advantages on simulating mean segment and extreme segment, therefore, re- searchers should choose the proper method based on the characteristics of test data and application purposes. [Conclusion] Analysis of soil heavy metal pollution is the prerequisite for soil management and ecological restoration. The result of this study is of important significance for choosing different interpolating and simulating methods to analyze soil heavy metal pollution based on different purposes.

金天格胶囊联合西药治疗强直性脊柱炎伴骨质疏松症40例临床观察

目的:观察金天格胶囊联合西药治疗强直性脊柱炎伴骨质疏松症患者的临床疗效及安全性。方法:将80例强直性脊柱炎伴骨质疏松症患者随机分为治疗组和对照组,每组40例。对照组给予沙利度胺、醋氯芬酸肠溶胶囊及维D钙咀嚼片治疗,治疗组在对照组的基础上予金天格胶囊治疗。2组疗程均为6个月。观察2组治疗前后骨密度、25羟基维生素D[25-(OH)D]、甲状旁腺激素(PTH)、疼痛视觉模拟评分法(VAS)评分、红细胞沉降率(ESR)、超敏C反应蛋白(hs-CRP)变化情况。结果:治疗后,2组骨密度、25-(OH)D、PTH、VAS评分、ESR、hs-CRP较治疗前均有显著改善(P<0.05);且治疗组优于对照组(P<0.05)。2组均未发现明显不良反应。结论:金天格胶囊联合西药治疗强直性脊柱炎伴骨质疏松症患者具有良好的抗骨质疏松、抗炎镇痛效果,安全性高。