MoS_(2)-In与MoS_(2)-Au异质结界面构型对势垒影响研究

文章采用第一性原理计算方法对比研究单层二硫化钼(MoS 2)与In、Au形成的异质结的界面构型对界面势垒的影响。能带结构和束缚能计算表明,MoS_(2)-In和MoS_(2)-Au异质结是范德华接触;由于界面In原子d轨道和Au原子s轨道电子态空间分布各向异性和各向同性,界面势垒对构型表现出不同的依赖性;MoS_(2)-In和MoS_(2)-Au异质结的界面势垒明显偏离Schottky-Mott定则的预测值,电子密度差分结果分析证明,界面电荷转移形成的偶极层是势垒偏离的主要原因。研究结果表明,通过界面构型调控偶极层是调控MoS_(2)-In和MoS_(2)-Au范德华异质结界面势垒的一种新方法。

TiN/γ-Fe interface orientation relationship and formation mechanism of TiN precipitates in Mn18Cr2 steel

A Mn18Cr2 steel containing TiN precipitates was fabricated by vacuum induction melting.The morphology of TiN precipitates and the interface orientation relationship between TiN and γ-Fe were characterized by means of SEM,TEM and SAED,and the formation mechanism of TiN precipitates in Mn18Cr2 steel was clarified.Results show that the TiN precipitates are more likely to exhibit a cubic-shaped morphology and form both within the grain and at the grain boundary of γ-Fe.The interface orientation relationship between TiN and γ-Fe is determined as follows:(100)_(TiN)//■_(γ-Fe),■_(TiN)//■_(γ-Fe).Because of the smallest interfacialmisfit,the secondary close-packed lane {100} of TiN preferentially combines with the close-packed plane {111} of γ-Fe during the precipitation in order to minimize the interface energy.After nucleation,the TiN precipitates exhibit cubic appearance due to the fact that the TiN has a FCC structure with rock salt type structure.This study provides reference for the material design of the austenitic high-manganese steels with excellent yield strength.

Imaging the crystal orientation of 2D transition metal dichalcogenides using polarization-resolved second-harmonic generation

We use laser-scanning nonlinear imaging microscopy in atomically thin transition metal dichalcogenides(TMDs)to reveal information on the crystalline orientation distribution,within the 2D lattice.In particular,we perform polarization-resolved second-harmonic generation(PSHG)imaging in a stationary,raster-scanned chemical vapor deposition(CVD)-grown WS2 flake,in order to obtain with high precision a spatially resolved map of the orientation of its main crystallographic axis(armchair orientation).By fitting the experimental PSHG images of sub-micron resolution into a generalized nonlinear model,we are able to determine the armchair orientation for every pixel of the image of the 2D material,with further improved resolution.This pixel-wise mapping of the armchair orientation of 2D WS2 allows us to distinguish between different domains,reveal fine structure,and estimate the crystal orientation variability,which can be used as a unique crystal quality marker over large areas.The necessity and superiority of a polarization-resolved analysis over intensity-only measurements is experimentally demonstrated,while the advantages of PSHG over other techniques are analysed and discussed.

Orientation dependence of elastic properties in orthorhombic Ca_3Mn_2O_7

Elastic properties are important in fundamental understanding of multiferroic materials. However, up to now, there is no work about anisotropy of elastic properties in orthorhombic Ca_3Mn_2O_7. In this study, using coordinate transformation method, we investigated basic elastic parameters(elastic constants c'_(ij)) and engineering elastic parameters(Young's modulus E, Poisson's ratio v, and the rigidity modulus G') of orthorhombic Ca_3Mn_2O_7 along arbitrary orientations. The detailed anisotropic characteristics of these parameters were presented. The results reveal the orientation related elastic properties in mm2 point group orthorhombic Ca_3Mn_2O_7.

MORPHOLOGY AND ORIENTATION CHARACTERISTICS OF DIRECTIONALLY SOLIDIFIED α(A1)-Mg_2Si EUTECTIC

Dependence of the morphology of α(Al)-Mg2Si eutectic on the solidification velocity, and its orientation characteristics were investigated by thermoanalysis, directional solidification and electron diffraction techniques in this study.The eutectic morphology transformed from lamellae to rods with the increasing of the solidification velocity. Simultaneously, the orientation relationship changed from (100)Mg2Si/(100)Al;[110]Mg2si/[110]al to (011)Mg2si/(121)Al;[111]Mg2Si/[111]Al and (010)Mg2Si/(110)Al; [100]Mg2Si/[111]Al. Transformation of the eutectic morphology was related to the change of the preferred orientation of phase Mg2si.

Laser Polarization Orientations in(e,2e)Reactions in Atoms

Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted （e, 2e） collisions for hydrogen and helium targets. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing the Volkov solutions in both the initial and final channels. Detailed calculations of the scattering amplitudes are performed using the Sturmian basis expansion. The state of the ejected electron is described by a Coulomb-Volkov wave function. Two geometries are investigated in which the laser polarization vector is either parallel to the incident momentum of the projectile or parallel to the momentum transfer. Our numerical results show that, in the low energy range, these two laser polarization orientations give the same shape and the same order of magnitude of laser-assisted ionization cross sections of helium and hydrogen targets.

磁控溅射与硫化热处理制备β-In_2S_3薄膜及光电性能

采用磁控溅射预制In薄膜和硫化热处理工艺制备了性能优良的β-In2S3 薄膜.应用XRD、拉曼光谱仪及UV-Vis测试仪对薄膜的品质进行了分析,并测试了薄膜的光学与电学性能.结果表明,溅射功率和硫化热处理温度是影响薄膜品质的主要因素,比较合适的溅射功率为100-140W,硫化热处理温度为450℃,过高的热处理温度容易在薄膜中形成缺陷,在薄膜生长过程中容易产生In5S4 杂相,相比之下,溅射气体压强对薄膜品质的影响较小,溅射气体压强可选择在0.4-0.6Pa.光学与电学性能测试结果指出,得到的β-In2S3 薄膜具有良好的光谱透过率,属n型半导体,可用于太阳能电池缓冲层.

磁控溅射与硫化热处理制备β-In2S3薄膜

采用磁控溅射预制In薄膜和硫化热处理工艺制备了性能优良的β一In2S3薄膜,应用XRD、拉曼光谱仪及UV一Vis测试对薄膜的品质进行了分析,并测试了薄膜的光学与电学性能, 结果表明,溅射功率对薄膜的结晶性能影响较大,比较合适的溅射功率为100W和140W.此外,硫化热处理温度对薄膜的品质影响也很大,比较合适的热处理温度范围为450.相比之下,溅射气体压强对薄膜品质的影响小一些,溅射气体压强可选择在04一0.6Pa.光学与电学性能测试结果指出,得到的β一In2S3薄膜品质较好,光谱透过率高,属n型半导体,可用于太阳能电池缓冲层.

高能球磨对Ag-SnO_2-In_2O_3合金材料性能的影响

以未球磨与球磨条件下制备的Ag-SnO_2-In_2O_3电接触材料为研究对象,采用宏观性能与微观组织结构对比分析的研究方法,通过XRD、OA、SEM、EDS等分析手段,系统研究了不同高能球磨参数对Ag-SnO_2-In_2O_3材料性能的影响。结果表明:Ag-SnO_2-In_2O_3粉末在球磨过程中经磨球冲击、摩擦、剪切和压缩后表面氧化膜破碎,露出了高Ag含量的表面,增加了烧结时Ag-Ag接触面积,进而显著提高烧结坯的致密度、抗弯强度等力学性能。优化的球磨工艺参数为:球磨转速300r/min,球磨时间30min,球料比为10∶1。

基于Gaofen-2影像和面向对象的椰子林分类研究

椰子是重要的热带经济作物,海南椰子种植面积占全国的90%以上。快速获取椰子种植面积及其空间分布信息对热带作物产业规划具有十分重要的作用。本研究基于国产Gaofen-2高分辨率卫星影像,以文昌市东郊镇为试验区,开展椰子林遥感分类研究。基于最优分割尺度的面向对象分类方法,选取4个光谱特征、5个植被指数和32个纹理特征为辅助参量,构建了4种不同的面向对象分类组合(光谱特征、光谱特征+纹理特征组合、光谱特征+植被指数组合、光谱特征+纹理特征+植被指数特征组合)进行椰子林分类提取,并与基于像元的椰子林分类结果进行对比分析。结果表明:(1)仅采用基于像元分类方法,椰子林的总体分类精度(overall accuracy,OA)和用户精度(user’s accuracy,UA)分别达到87.05%和85.21%。(2)相比基于像元分类,4种面向对象分类组合的OA值提高了5.51%~8.72%。(3)光谱特征和纹理特征组合提取椰子林分类结果最优,OA值和UA值分别达到95.77%和97.15%;光谱特征和植被指数的组合也得到了较好的分类结果,OA值和UA值分别为94.88%和94.42%;所有的光谱特征、植被指数和纹理特征全部参与分类得到的OA值和UA值分别为94.67%和94.17%,低于仅使用光谱特征或者植被指数的组合。综上,国产高分辨率Gaofen-2影像在椰子林遥感精准识别中具有很大的潜力,结合纹理特征的面向对象分类方法可以更准确地提取椰子林分类信息,研究结果可为多云多雨地区大尺度椰子林遥感识别提供技术参考。

基于哨兵2号数据的撂荒地识别与分析——以甘肃省麦积区为例

以甘肃省麦积区为研究区域,采用哨兵2号遥感卫星数据,并基于面向对象的方法对该区域的撂荒地进行了识别,分类总体精度达到92%,Kappa系数为0.82。空间统计结果显示,麦积区的撂荒地面积为12600.31 hm^(2),占麦积区总面积的3.62%,占耕地总面积的22.02%。坡度分析和交通条件分析发现,地形因素和交通条件是导致撂荒的重要原因。对麦积区的撂荒地进行空间自相关分析发现,撂荒地存在显著的空间集聚特征。

Fe_2O_3-In_2O_3复合薄膜光波导传感元件检测二甲苯气体的研究

采用溶胶-凝胶法(sol-gel)制备出氧化铁-氧化铟复合材料,利用提拉法将复合材料固定在锡掺杂玻璃光波导表面研究出能够检测二甲苯气体的Fe2O3-In2O3复合薄膜/锡掺杂玻璃光波导气敏元件。将气敏元件固定在气体检测系统中对挥发性有机气体进行检测。实验结果表明,Fe2O3-In2O3复合薄膜/锡掺杂玻璃光波导气敏元件对二甲苯气体具有较好的响应,其响应浓度范围为1×10-3～1×10-5(V/V)。在常温下该敏感元件对于浓度为1×10-5(V/V)的二甲苯蒸汽有比较明显响应,其响应和恢复时间分别为5s和20s。Fe2O3-In2O3复合薄膜/锡掺杂玻璃光波导气敏元件具有灵敏度高、响应速度快、制作工艺简单和可逆性好等特点。

以目标管理为导向的健康教育 在初发2型糖尿病患者护理中的应用效果分析

目的:分析以目标管理为导向的健康教育在初发2型糖尿病患者护理中的应用价值。方法:抽取2022年1月—2023年6月于滨州市中心医院确诊的初发2型糖尿病74例作为观察样本,通过随机数字表法分为对照组、观察组,各37例。对照组采用常规护理,观察组在对照组基础上采用以目标管理为导向的健康教育。比较两组护理效果。结果:护理后,两组空腹血糖、餐后2 h血糖、糖化血红蛋白水平以及体质量指数下降,且观察组较对照组低(P<0.05)。护理后,两组饮食管理、运动锻炼、血糖监测、自我足部检查、遵医嘱用药评分升高,且观察组较对照组高(P<0.05)。护理后,两组躯体功能、物质生活、社会功能、心理职能评分升高,且观察组较对照组高(P<0.05)。结论:以目标管理为导向的健康教育在初发2型糖尿病患者护理中的应用价值较高,能够有效提升患者的自我管理能力以及生活质量,更好地控制其血糖水平。

UV-Enhanced Room Temperature Ozone Sensor Based on Hierarchical SnO_2-In_2O_3

SnO2-ln2O3 hierarchical microspheres were prepared by the hydrothermal and solvothermal method. The morphology, phase crystallinity of the obtained SnO2-In203 were measured by X-ray diffraetion（XRD）, scan electron microscopy（SEM）, respectively. A room temperature ozone sensor based on SnO2-In2O3 hierarchical microspheres was fabricated and investigated. The gas sensing properties of the sensor using SnO2-In2O3 strongly depended on the proportion of SnO2 and In2O3. The sensitivity and response/recovery speed were greatly enhanced by UV illumination. A gas sensing mechanism related to oxygen defect was suggested.

High temperature thermoelectric properties of highly c-axis oriented Bi_2Sr_2Co_2O_y thin films fabricated by pulsed laser deposition

High-temperature thermoelectric transport property measurements have been performed on the highly c-axis oriented Bi2Sr2Co20v thin films prepared by pulsed laser deposition on LaA1Oa （001）. Both the electric resistivity p and the seebeck coefficient S of the film exhibit an increasing trend with the temperature from 300 K-1000 K and reach up to 4.8 m. cm and 202 V/K at 980 K, resulting in a power factor of 0.85 mW/mK which are comparable to those of the single crystalline samples. A small polaron hopping conduction can be responsible for the conduction mechanism of the film at high temperature. The results demonstrate that the Bi2Sr2Co2Oy thin film has potential application has high temperature thin film thermoelectric devices,

50W800无取向硅钢中Al_(2)O_(3)和Al_(2)O_(3)-MnS夹杂物的腐蚀行为研究

采用无取向硅钢退火样进行原位腐蚀实验,对试样表面腐蚀形貌进行OM表征、SEM表征、EDS分析、拉曼光谱表征。结果表明,无取向硅钢的腐蚀源自夹杂物的局部腐蚀,其中包含金属氧化物夹杂Al_(2)O_(3)、金属氧硫化物夹杂Al_(2)O_(3)-MnS。无取向硅钢初期腐蚀时圆形锈斑内腐蚀产物主要为γ-FeOOH和α-Fe_(2)O_(3),且γ-FeOOH含量高于α-Fe_(2)O_(3)。随着腐蚀产物的颜色加深,α-Fe_(2)O_(3)含量逐渐增多。

h‑MoO_(3)/SiO_(2)催化合成季戊四醇异辛酸酯

采用固相研磨法,制备了一系列h-MoO_(3)/SiO_(2)催化剂,这些催化剂用于季戊四醇(PER)和异辛酸(i-EHA)反应,合成季戊四醇异辛酸酯(POE),并采用X射线衍射(XRD)、傅里叶红外光谱(FTIR)、X射线光电子能谱(XPS)、N2吸附-脱附、扫描电镜(SEM)、透射电镜(TEM)对催化剂进行表征测试。结果表明,h-MoO_(3)负载量为15%的(200)晶面择优取向的h-MoO_(3)/SiO_(2)是合成POE的优良催化剂。适宜的反应工艺条件(ni-EHA/nPER=4.3,mh-MoO_(3)/SiO_(2)/mPER=0.003,T=220℃,t=4 h)下,酯化率可达90.83%,POE的选择性可达100%。

Mg掺杂增强CuCrO_(2)陶瓷的电传导及各向异性

采用固相反应法制备了具有c轴择优的CuCr_(1-x)Mg_(x)O_(2)(x=0、0.005、0.010、0.020、0.030、0.040、0.050)系列多晶,分别从垂直和平行于压力的宏观面内方向和厚度方向研究Mg掺杂对CuCrO_(2)多晶微结构取向和电性能及各向异性的影响,探讨了Mg掺杂增强CuCrO_(2)陶瓷电导率各向异性的机制。当x≤0.030时,多晶为菱方R3m单相结构,随着掺杂量的增加,晶粒在面内充分长大,气孔和晶界减少,致密度逐渐提高,多晶呈现热激活半导体电输运行为;当x=0.030时,面内取向因子F((00l))达到最高值0.912,面内c轴择优取向远优于厚度方向,面内和厚度方向的CuCr_(1-x)Mg_(x)O_(2)多晶室温电阻率分别显著下降至1.80×10^(-3)和3.16×10^(-3)Ω·m,这是由于其结构各向异性的差异,热激活能均减小至0.03 eV,c轴择优取向对热激活能影响并不明显,最大载流子浓度比母相均增加3个量级,晶界缺陷更少,平均自由程增大,输运能力更强,电导率更高。实验表明最优掺杂量为x=0.030,当掺杂量x高于0.030时,出现MgCr_(2)O_(4)尖晶石杂相,样品的微观结构和电输运性能变差。

基于目标导向的护理干预结合回授法对初诊2型糖尿病肾病患者自我管理能力及负性情绪的回顾性分析

目的分析基于目标导向的护理干预结合回授法在初诊2型糖尿病肾病患者中的应用价值。方法回顾性选取2022年6月—2023年6月枣庄市立医院收治的98例2型糖尿病肾病患者的临床资料,根据护理方法的不同分为两组,各49例。对照组实施常规护理,研究组实施基于目标导向的护理干预结合回授法。干预前及干预3个月,检测两组空腹血糖(fasting plasma glucose,FPG)、餐后2 h血糖(2-hour postprandial plasma glucose,2 hPG)水平,同时对比自我管理行为量表(Summary of Diabetes Self-Care Activities,SDSCA)、汉密尔顿焦虑量表及汉密尔顿抑郁量表评分。结果干预3个月,研究组FPG及2 hPG水平、负性情绪评分均低于对照组,SDSCA评分高于对照组,差异有统计学意义(P均<0.05)。结论初诊2型糖尿病肾病患者实施基于目标导向的护理干预结合回授法,能够提高患者自我管理能力,降低血糖水平,并改善负性情绪。

F^(-)掺杂ZrO_(2)粉体的水热合成及光催化性研究

采用水热合成法以HF为矿化剂制备了具有较高光催化性的F-掺杂ZrO_(2)纳米材料,系统研究F-对ZrO_(2)纳米粉体相组成、形貌、晶体生长及光催化性能的影响。结果表明:F^(-)的引入促进四方相ZrO_(2)向单斜相的相转化。矿化剂HF掺杂浓度的增加,促进单斜相ZrO_(2)初始生长基元晶粒的生长以及二次颗粒的长大。F^(-)在ZrO_(2){001}晶面上的吸附使ZrO_(2)的初始棒状晶粒趋向于沿[001]方向生长,同时也促进棒状晶粒在{001}晶面定向附生形成纺锤状三维颗粒。在60 min的光照条件下,所有F^(-)掺杂的ZrO_(2)粉末对甲基橙的降解效率均可达到80%以上。0.04 F/ZrO_(2)催化剂的光催化性能最高,在60 min内甲基橙的降解率可达91.7%。