Anomalous bond lengthening in compressed magnetic doped semiconductor Ba(Zn_(0.95)Mn_(0.05))_(2)As_(2)

Applying pressure has been evidenced as an effective method to control the properties of semiconductors,owing to its capability to modify the band configuration around Fermi energy.Correspondingly,structural evolutions under external pres-sures are required to analyze the mechanisms.Herein high-pressure structure of a magnetic doped semiconductor Ba(Zn_(0.95)Mn_(0.05))_(2)As_(2)is studied with combination of in-situ synchrotron X-ray diffractions and diamond anvil cells.The materials become ferromagnetic with Curie temperature of 105 K after further 20%K doping.The title material undergoes an isostruc-tural phase transition at around 19 GPa.Below the transition pressure,it is remarkable to find lengthening of Zn/Mn-As bond within Zn/MnAs layers,since chemical bonds are generally shortened with applying pressures.Accompanied with the bond stretch,interlayer As-As distances become shorter and the As-As dimers form after the phase transition.With further compres-sion,Zn/Mn-As bond becomes shortened due to the recovery of isotropic compression on the Zn/MnAs layers.

原位电化学扫描探针显微镜技术在电催化领域的应用进展

在电化学界面,电催化过程通常包括电子转移、吸附和脱附、静电相互作用、溶剂化及去溶剂化等多步过程,深入理解电催化反应机理极具挑战性.对纳米结构电化学界面(电极)处电催化过程的深入理解十分有助于阐明电催化反应机理和设计高性能电催化剂材料.电催化活性通常与电催化剂表面局域化的活性位点密切有关.在反应条件下,电催化反应过程的研究极大依赖于高分辨表征技术.经典的宏观电化学表征方法仅可以提供不同界面位点的平均信息,很难分辨一些特殊结构位点(如缺陷、晶界、边缘位点)的相关重要电化学信息.原位电化学扫描探针显微镜技术,包括电化学扫描隧道显微镜(EC-STM)、电化学原子力显微镜(EC-AFM)、扫描电化学显微镜(SECM)及扫描电化学池显微镜(SECCM),能够在纳米及原子尺度研究电催化反应过程,弥补了宏观表征方法的不足,为探究构效关系和解析电催化反应机理提供了机遇.本文介绍了各种扫描显微技术的基本原理、特点及优劣势,并且概述了各项技术在电催化领域研究的重大进展.EC-STM和EC-AFM能够原位表征电催化过程中的纳米尺度表面结构演变及吸附/脱附过程,但无法直接测量局部电化学活性(法拉第电流).通过SECM和SECCM可以检测微区电化学信号,并获得电化学通量和电化学反应动力学信息,可作为EC-STM和EC-AFM的补充技术.结合二者的优势,进一步介绍了双探针结合技术(SECM-AFM,SECM-STM,SECM-SICM及SECM-SECCM)的原理和关键电催化应用.随后,从揭示构效关系、结构演变/稳定性、反应物或中间物的吸附、反应路径和选择性等角度,总结了这些原位电化学扫描探针显微镜技术在电催化领域(析氢反应、氢氧化反应、析氧反应、氧还原反应及CO_(2)还原反应)的最新研究进展.最后,对原位电化学扫描探针显微镜技术在电催化领域研究的挑战及未来发展进行了展望.

Colossal negative magnetoresistance in spin glass Na(Zn,Mn)Sb

We report the study of magnetic and transport properties of polycrystalline and single crystal Na(Zn,Mn)Sb,a new member of“111”type of diluted magnetic materials.The material crystallizes into Cu2Sb-type structure which is isostructural to“111”type Fe-based superconductors.With suitable carrier and spin doping,the Na(Zn,Mn)Sb establishes spin-glass ordering with freezing temperature(Tf)below 15 K.Despite lack of long-range ferromagnetic ordering,Na(Zn,Mn)Sb single crystal still shows sizeable anomalous Hall effect below Tf.Carrier concentration determined by Hall effect measurements is over 1019 cm-3.More significantly,we observe colossal negative magnetoresistance(MR≡[ρ(H)−ρ(0)]/ρ(0))of-94%in the single crystal sample.

金桔精油通过抑制p38 MAPK和NF-κB信号通路减轻脂多糖诱导的小鼠急性肺损伤（英文）

目的:探讨金桔精油(KEO)对脂多糖(LPS)诱导的急性肺损伤(ALI)小鼠的保护作用及机制。方法:将72例昆明雄性小鼠随机分为6组:对照组、LPS组、地塞米松(DXMS)组、低剂量KEO(KEOL)组、中剂量KEO(KEOM)组和高剂量KEO(KEOH)组,每组12只。连续灌胃给药7d后,除对照组外,其他各组小鼠均通过腹腔注射LPS(10mg/kg)复制ALI模型。计算肺湿重与体重的比值(LW/BW)。光镜下观察肺组织病理学改变。采用免疫组织化学染色法检测肺组织中肿瘤坏死因子(TNF)-α和连接蛋白(Cx)-43的表达,酶联免疫吸附试验(ELISA)法检测血清白细胞介素(IL)-1β和IL-6水平,Western blotting法测定核因子(NF)-κB p65、IκBα、p38丝裂原活化蛋白激酶(MAPK)磷酸化水平及诱导型一氧化氮合酶(iNOS)和环氧合酶(COX)-2蛋白表达量。结果:KEO预处理可显著改善LPS诱导的肺组织病理学改变。与LPS组相比,KEOM和KEOH组LW/BW比值、TNF-α、Cx-43、COX-2和iNOS蛋白表达量以及血清IL-6和IL-1β水平均明显降低(均P<0.05)。同时,不同剂量KEO组磷酸化(p)-p38,p-p65和p-IκBα表达下调(P<0.05),以KEOH组最为显著。结论:KEO对LPS诱导的小鼠ALI有保护作用,其机制可能与阻断p38MAPK和NF-κB信号通路和减轻炎症反应有关。

过渡金属单原子功能化碳载体促进碱性氢电催化反应动力学

碱性阴离子膜燃料电池和电解水制氢技术对氢能的高效循环利用非常关键.然而,碱性条件下析氢反应(HER)和氢氧化反应(HOR)动力学缓慢,大大降低了燃料电池和电解池的能量转换效率.因此,开发综合性能优异的电催化剂以提高碱性环境下HER和HOR动力学至关重要.传统电催化剂的一个典型设计思路是将活性材料负载于具有高导电性和大比表面积的碳载体上.一般来说,碳载体能够促进活性材料的均匀分散并显著增加其催化活性位点的暴露,但是碳载体本身往往很难参与电催化反应,导致复合催化剂活性位点单一,不利于高效催化涉及较多中间体的复杂反应(碱性条件下的HOR和HER).另一方面,当前电催化剂研究通常局限于调控活性材料和载体的界面结构或者专注于调控活性材料本征结构,对催化剂载体进行调控并作为助催化剂的研究尚不多见.本文采用过渡金属单原子对碳载体进行功能化及电子结构调控,并研究此类碳载体在碱性HER和HOR反应中的助催化作用.合成了一系列金属单原子修饰的碳载体M-N-C(过渡金属包括Mn,Fe,Co,Ni,Cu,Mo,Ag),并系统研究了M-N-C在Pt电催化HOR和HER中的作用.结果表明,过渡金属单原子修饰的碳载体的催化促进作用与过渡金属的电负性以及3d轨道电子填充度密切相关.一方面,不同过渡金属M与氧的亲和力不同,并可以通过界面M–O–Pt键调节Pt的电子结构.过渡金属电负性越小,Pt表面的电子密度则越大,有助于加速Had在Pt表面的结合/解离步骤,因此提升了HOR和HER反应速率.另一方面,过渡金属的3d轨道未填充程度越高,则越有利于增强其与氧2p轨道的耦合作用,所形成的M-N4结构对于水分子和OH_(ad)的吸附也大大增强,最终通过促进Volmer步骤加快氢的电催化反应速率.结果显示,除Cu和Ag单原子修饰的碳载体之外,其它几种过渡金属功能化的碳载体均能够通过促进Volmer反应步骤以加快碱性条件下Pt的HOR和HER电催化反应速率,其中效果最为显著的是锰单原子修饰的碳载体.Mn-N-C/Pt(1.48 mA cm_(Pt)^(–2))的质量比交换电流密度比商业化20%Pt/C(0.26 mA cm_(Pt)^(–2))提高了约4.7倍.综上所述,本工作证明了开发多功能碳载体用于异相催化反应的重要性,并且为未来开发高效电催化剂提供了新的思路.

Advances in new generation diluted magnetic semiconductors with independent spin and charge doping

As one branch of spintronics, diluted magnetic semiconductors (DMSs) are extensively investigated due to their fundamental significance and potential application in modern information society. The classical materials (Ga,Mn)As of III-V group based DMSs has been well studied for its high compatibility with the high-mobility semiconductor GaAs. But the Curie temperature in (Ga,Mn)As film is still far below room temperature because the spin & charge doping is bundled to the same element that makes the fabrication very difficult. Alternatively, the discovery of a new generation DMSs with independent spin and charge doping, such as (Ba,K)(Zn,Mn)2As2 (briefly named BZA), attracted considerable attention due to their unique advantages in physical properties and heterojunction fabrication. In this review we focus on this series of new DMSs including (I) materials in terms of three types of new DMSs, i.e. the "111","122" and "1111" system;(II) the physical properties of BZA;(III) single crystals & prototype device based on BZA. The prospective of new type of DMSs with independent spin and charge doping is briefly discussed.

siRNA沉默STAT5对食管癌EC9706细胞增殖、凋亡和侵袭的影响(英文)

Objective:The aim of the study was to explore the effect of STAT5 silenced by siRNA on proliferation,apoptosis and invasion of esophageal carcinoma cell line EC9706.Methods:The siRNA vectors aiming to STAT5 gene were constructed.STAT5 siRNA was transfected into EC9706 cells by Lipofectamine TM 2000.Changes of STAT5,Bcl-2 and Cyclin D1 were analyzed by Western blot and RT-PCR.Effect of STAT5 siRNA on EC9706 cells proliferation was determined by MTT.Effects of STAT5 siRNA on EC9706 cells cycle and apoptosis were detected by the flow cytometry.Boyden chamber was used to evaluate the invasion and metastasis capabilities of EC9706 cells.Results:The double strands oligonucleotide of siRNA aiming to STAT5 was successfully cloned into the pRNAT-U6.1 vector,and the target sequence was coincide with the design.RT-PCR and Western blotting detection demonstrated that the expression levels of STAT5,Bcl-2 and Cyclin D1 genes were obviously decreased in EC9706 cells transfected with STAT5 targeting siRNA expression vectors.STAT5 siRNA could suppress the proliferation of EC9706 cells.The proportions of S and G2/M periods frequency were significantly decreased (P < 0.05),and the proportion of G0/G1 period frequency was significantly increased (P < 0.05).The average amount of cells penetrating Matrigel was significantly decreased (P < 0.05).Silencing the STAT5 induced the apoptosis of esophageal carcinoma cell line EC9706 (P < 0.01).Conclusion:STAT5 silenced by siRNA of esophageal carcinoma cell line EC9706 could induce the apoptosis.And it could suppress the proliferation,invasion and metastasis of tumor cells.

RNAi抑制Bmi-1基因表达对Jurkat细胞的影响(英文)

Objective: The aim of our study was to investigate the effects of down-regulation Bmi-1 by RNA interference (RNAi) in T Lymphocytic leukemia Jurkat cells. Methods: Two complementary oligonucleotide strands were synthesized based on the siRNA sequence targeting Bmi-1 gene. After annealing, siRNA strands were recombined into the pRNAT-U6.2 vector, and then DNA sequencing was carried out following transformation and amplification. The recombinant was transfected into Jurkat cells with liposomes. Positive colonies were obtained through G418 selection. The mRNA and protein expressions of Bmi-1 were detected by RT-PCR and Western-blot, respectively. Effects of Bmi-1 silence on cell proliferation, cell cycle and cell aging of Jurkat cells were detected by MTT assay, flow cytometry, colony formation assay and SA-β-Gal staining, respectively. Results: The siRNA recombinant targeting Bmi-1 gene was successfully constructed. All three siRNA recombinants could significantly inhibit the expression of Bmi-1. The siRNA targeting 825nt-843nt (GACCAGACCACTACT GAAT) has the strongest inhibitory effect on Bmi-1 expression, with almost complete inhibition on Bmi-1 mRNA and protein expressions. Compared with the non-transfection group and the empty vector group, growth velocity and colony formation ability were significantly decreased, while the proportion of cells in G1 phase and the percentage of senile cells were signifi-cantly increased in highly transfected group (P < 0.05). Conclusion: Down-regulation Bmi-1 by RNA interference (RNAi) could significantly inhibit the growth of Jurkat cells in vitro.

RNAi干扰食管癌EC9706细胞MTA1基因表达对侵袭和迁移的影响(英文)

Objective: To observe the effect of MTA1 gene silencing by RNA interference on invasion and migration of esophageal carcinoma 9706 cells. Methods: siRNA expression vector targeting MTA1 gene was transfected into EC9706 cells by Lipofectamine method. MTA1 mRNA and protein expressions were detected through quantitative RT-PCR and Western Blot, respectively. The invasion and migration of EC9706 cells were evaluated by scrape wound healing assay and cell invasion assay in vitro. Results: MTA1 gene expression decreased significantly. The scrape wound of EC9706 cells healed more slowly and the cell population that cut through Matrigel were less in the EC9706 cells transfected with siRNA expression vector than non-transfected EC9706 cells and EC9706 cells transfected with blank vector (P < 0.05). Conclusion: MTA1 gene silencing by RNAi can inhibit the invasion and migration of esophageal carcinoma effectively. It is supposed that MTA1 gene may be a prospective molecule target in tumor therapy.

过表达人血管生成素样蛋白4对食管癌EC9706细胞生长的影响(英文)

Objective:The aim of the study was to construct the eukaryotic expression vector of human angiopoietin-like protein 4(ANGPTL4) and observe the effect of ANGPTL4 overexpression on the growth of esophageal carcinoma EC9706 cells.Methods:Total RNA was extracted from normal hepatic tissue,and ANGPTL4 cDNA was amplified by RT-PCR.The PCR product was doubly digested by XbaI and SalI,and then recombined into eukaryotic expression vector.Then,pIRES-GFP-ANGPTL4 was obtained by G418 selection,then pIRES-GFP-ANGPTL4 and pIRES-GFP were transfected into EC9706 cells with lipidosome-packaged method.Meanwhile,the transfected cells were selected by G418,and then stable transfected cell lines were obtained.ANGPTL4 mRNA levels,the cell cycles and growth curves of EC9706 cells in experiment group(transfected with pIRES-GFP-ANGPTL4),empty vector group(transfected with pIRES-GFP) and blank control group(EC9706 cells without transfection) were detected with RT-PCR,flow cytometry and MTT methods,respectively.Results:Eukaryotic ANGPTL4 expression vector pIRES-GFP-ANGPTL4 was successfully constructed.The ANGPTL4 mRNA level(0.21 ± 0.03) in experiment group was significantly higher than that of the empty vector group(0.04 ± 0.008) and the blank control group(0.05 ± 0.007),with significant differences(P < 0.01).The proportion of cells in S phase in experiment group was significantly different with those of the other two groups(P < 0.05).The cell growth of EC9706 cells in experiment group was slower than those of the other two groups.From the third day,the differences began to be significant.Conclusion:ANGPTL4 overexpression in esophageal carcinoma EC9706 cells could inhibit the growth of EC9706 cells.

CEA siRNA载体的构建和转染人食管癌EC9706细胞的沉默作用(英文)

Objective: To construct the small interfering RNA (siRNA) expression vector of carcino-embryonic antigen (CEA) and inhibit the expression of CEA in EC9706 cells by RNA interference. Methods: Two pairs of oligonucleotide sequences were designed and synthesized according to the encoding sequence of mRNA of CEA. The annealed oligonucleotide frag-ments were cloned into pRNAT-U6.2 expression vector and identified by sequencing. The recombinant plasmid pRNAT-U6.2-CEA was transfected into EC9706 cells. The expression of CEA in the stable transfected cells was assayed by real time PCR and Western blot. Results: DNA sequencing showed that the oligonucleotide fragments were correctly inserted into pRNAT-U6.2 vector, and CEA expression in the transfected cells was down-regulated significantly by pRNAT-U6.2-CEA at both the mRNA and protein levels. Conclusion: The siRNA expression vector of CEA is successfully constructed and inhibits CEA expression in EC9706 cells. This facilitates further studies of the function of CEA at the molecular level.

露天采矿爆破振动监测与控制分析

随着中国社会的发展和科技的进步,中国对矿业的需求也不断增加,开采露天矿对爆破操作规范及要求极为严格。同时,如果爆破振动过大将会对临近的建筑物、高压线等设施造成一定的影响。因此,笔者对本次露天矿爆破进行振动检测,并对其结果进行控制和分析,以期为采场周边建筑物的安全防护提供科学依据。

Epitaxial interface stabilizing iridium dioxide toward the oxygen evolution reaction under high working potentials

Proton exchange membrane water electrolyzer(PEMWE)driven by renewable electricity is a promising technique toward green hydrogen production,but the corrosive environment and high working potential pose severe challenges for developing advanced electrocatalysts for the oxygen evolution reaction(OER).Although Ir-based materials possess relatively balanced activity and stability for the OER,their dissolution behavior cannot be neglected,in particular under high working potentials.In this work,iridium dioxide(IrO_(2))nanoparticles(NPs)were anchored on the surface of exfoliated h-boron nitride(BN)nanosheets(NSs)toward the OER reaction in acid media.Highly active Ir(V)species were stabilized by the epitaxial interface between IrO_(2)and h-BN,and therefore the IrO_(2)/BN delivered stable performance at increased working potentials,while the activity of bare IrO_(2)NPs without h-BN support decreased rapidly.Also,the smaller lattice spacing of h-BN induced compressive strain for IrO_(2),resulting in improved activity.Our results demonstrate the feasibility of stabilizing highly active Ir(V)species for the OER in acid media by constructing robust interface and provide new possibilities toward designing advanced heterostructured electrocatalysts.

A joint InSAR-GNSS workfow for correction and selection of interferograms to estimate high-resolution interseismic deformations

Knowledge of the spatial distribution of interseismic deformations is essential to better understand earthquake cycles.The existing methods for improving the reliability of the obtained deformations often rely on visual inspection and prior model corrections that are time-consuming,labor-intensive,and do not consider the spatial distribution of interseismic deformations.Interferometric Synthetic Aperture Radar(InSAR)data provides wide-scale coverage for interseismic deformation monitoring over a wide area.However,the interseismic signal featured as millimeter-scale and long-wave deformations is often contaminated with noise.In the present study,a new workfow to correct the interferometric phase and quantitatively select interferograms is proposed to improve the accuracy of interseismic deformation measurements.Initially,the Generic Atmospheric Correction Online Service(GACOS),Intermittent Code for Atmospheric Noise Depression through Iterative Stacking(I-CANDIS),and plate model are combined to correct the atmospheric screen and long-wave ramp phase.Subsequently,the Pearson’s Correlation Coefcient(PCC)between the interferometric phase and the Global Navigation Satellite System(GNSS)constrained interseismic model as well as the STandard Deviation(STD)of the interferometric phase are introduced as criteria to optimize the selection of interferograms.Finally,the intermittent stacking method is used to generate an average velocity map.A comprehensive test using Sentinel-1 images covering the Haiyuan Fault Zone validate the efectiveness of our workfow in measuring interseismic deformations.This demonstrates that the proposed joint InSAR-GNSS workfow can be extended to study the subtle interseismic deformations of major fault systems in Tibet and worldwide.

Ferromagnetism at 230 K in(Ba_(0.7)K_(0.3))(Zn_(0.85)Mn_(0.15))_2As_2 diluted magnetic semiconductor

We report the ferromagnetism with Cure temperature Tcat 230 K in a new diluted magnetic semiconductor(DMS)(Ba0.7K0.3)(Zn0.85Mn0.15)2As2isostructural to ferropnictide 122 superconductors synthesized via low temperature sintering.Spin is doped by isovalence substitution of Mn2+for Zn2+,while charge is introduced by heterovalence substitution of K1+for Ba2+in(Ba0.7K0.3)(Zn0.85Mn0.15)2As2DMS,being different from(Ga,Mn)As where both spin&charge are induced simultaneously by heterovalence substation of Mn2+for Ga3+.The(Ba0.7K0.3)(Zn0.85Mn0.15)2As2DMS shows spontaneous magnetization following T3/2dependence expected for a homogeneous ferromagnet with saturation moment 1.0μB for each Mn atom.

界面工程构建用于碱性氢电催化反应的高性能异质结构电催化剂

提升碱性氢析出反应(HER)和氧化反应(HOR)的电催化动力学,是发展高性能碱性聚合物电解质膜水电解槽和燃料电池的关键.碱性HER和HOR涉及到多种中间物的吸附,反应动力学缓慢.利用界面工程构建异质结构电催化剂在这类反应中具有独特优势.一方面,不同的异质结构组分之间可能存在着协同效应,能够平衡多种中间物的吸附行为,从而显著加快反应动力学.另一方面,异质界面处的特殊结构及强相互作用,包括电子相互作用、晶格失配、以及界面化学键等,可以调控活性中心的电子结构,有效提高其本征催化活性.另外,界面限域效应有助于维持电催化剂的结构均一性和稳定性.本文主要评述界面工程构建用于碱性氢电催化反应的异质结构电催化剂的研究进展与现状,并展望未来的研究发展方向,为开发新一代高性能低成本电催化剂提供研究思路.

Homological Behavior of Relative Cotorsionfree and Cosyzygy Modules

As the dual of the Auslander transpose and the resulting k-torsionfree module,the cotranspose and k-cotorsionfree module with respect to a semidualizing bimodule have been introduced recently.In this paper we first investigate the relation between relative k-cotorsionfree modules and relative k-cosyzygy modules.Then we study the extension closure of these two classes of modules.

Orbital selection of the double [CuO2] layer compound Ca3Cu2O4Cl2

The discovery of high-temperature copper oxide superconductors(HTS)by Bednorz and Muller[1]in 1986 opened up a new field of superconductivity.Since then,several different families of materials have been discovered with greatly increased superconducting critical temperature(Tc)[2].Oxychloride cuprates,Can+1CunO2wCl2,are one such type of parent compound of high Tc cuprate superconductors.There are two members in this family known so far that can exist at ambient pressure:Ca2CuO2Cl2(single[Cu02]layer CCOC)and Ca3Cu2O4Cl2(double[CuO2]layer CCOC).Both are composed of a[CuO2]plane with the apical oxygen replaced by chlorine atoms.

Parameter influence law analysis and optimal design of a dual mass flywheel

The influence of the dynamic parameters of a dual mass flywheel(DMF)on its vibration reduction performance is analyzed,and several optimization algorithms are used to carry out multiobjective DMF optimization design.First,the vehicle powertrain system is modeled according to the parameter configuration of the test vehicle.The accuracy of the model is verified by comparing the simulation data with the test results.Then,the model is used to analyze the influence of the moment of inertia ratio,torsional stiffness,and damping in reducing DMF vibration.The speed fluctuation amplitude at the transmission input shaft and the natural frequency of the vehicle are taken as the optimization objectives.The passive selection method,multiobjective particle swarm optimization,and the nondominated sorting genetic algorithm based on an elite strategy are used to carry out DMF multiobjective optimization design.The advantages and disadvantages of these algorithms are evaluated,and the best optimization algorithm is selected.

焦炉气加氢脱硫催化剂的研究

以高浓度CO、CO_2焦炉气为原料,对催化剂CNDS-19分别进行了脱氧、脱烯烃、脱硫活性测试,并考察了催化剂抑制甲烷化副反应能力,确定了两段反应的实验条件,对催化剂CNDS-19进行了1000h寿命实验,结果表明:当一段反应温度260℃,空速2000h,二段反应温度360℃,空速1000h,压力2.5-2.8MPa时,催化剂加氢活性高,稳定性好,尾气噻吩含量始终维持在0.1ppm以下,总的碳基甲烷化率为1.94%。