Surface Patterning of Metal Zinc Electrode with an In‑Region Zincophilic Interface for High‑Rate and Long‑Cycle‑Life Zinc Metal Anode

The undesirable dendrite growth induced by non-planar zinc(Zn)deposition and low Coulombic efficiency resulting from severe side reactions have been long-standing challenges for metallic Zn anodes and substantially impede the practical application of rechargeable aqueous Zn metal batteries(ZMBs).Herein,we present a strategy for achieving a high-rate and long-cycle-life Zn metal anode by patterning Zn foil surfaces and endowing a Zn-Indium(Zn-In)interface in the microchannels.The accumulation of electrons in the microchannel and the zincophilicity of the Zn-In interface promote preferential heteroepitaxial Zn deposition in the microchannel region and enhance the tolerance of the electrode at high current densities.Meanwhile,electron aggregation accelerates the dissolution of non-(002)plane Zn atoms on the array surface,thereby directing the subsequent homoepitaxial Zn deposition on the array surface.Consequently,the planar dendrite-free Zn deposition and long-term cycling stability are achieved(5,050 h at 10.0 mA cm^(−2) and 27,000 cycles at 20.0 mA cm^(−2)).Furthermore,a Zn/I_(2) full cell assembled by pairing with such an anode can maintain good stability for 3,500 cycles at 5.0 C,demonstrating the application potential of the as-prepared ZnIn anode for high-performance aqueous ZMBs.

Transport patterns and numerical simulation of heavy metal pollutants in soils of lead–zinc ore mines

Exploring transport patterns of soil contaminants is essential for solving the problem of heavy metal contamination in mine soils.In this study,contamination of Pb,Zn,and Cd in the mountain soils of the lead–zinc ore mines in Ganxi Township,Hengdong County,Hunan Province,China was investigated,and their transport patterns were further explored using a soil-column model and numerical simulation techniques.In total,111 mine soil samples were collected and placed into six experimental soil columns.By controlling the water flow,a control soil column group(CK),two mixed soil columns X1 with daily water flows of 1 and 5 L,and three mixed soil columns X3 with daily water flows of 2,3,and 4 L were evaluated.The results showed that the residual fraction of Pb accounted for 71.93%of the content on average,whereas the exchangeable fractions of Zn,Cd,and Fe-Mn oxide-bound fractions of Zn and Cd accounted for 28.60%,31.07%,and 43.2%and 53.54%of the content,respectively.Pb,Zn,and Cd in the soils of the CK,X1,and X3 groups mainly were accumulated at a depth from approximately 0 to 20 cm,and the content at this depth accounted for 60.09%of that at a 0~40 cm depth.The soil at a depth range of 0~10 cm was most seriously contaminated,and the proportion of content was 32.39%of that at a 0~40 cm depth.Numerical simulation showed that on the 5 th day,the pollutant transport range was 0~24 cm,and on the 9 th day,the pollutant transport range exceeded 40 cm.On the 15 th day,the transport capacity of pollutants at depths of 0~40 cm was close to the stable state,but the soil at a depth of 0~10 cm was still heavily polluted.These results reflect the transport pattern of heavy metal pollutants in the soil of lead–zinc ore mines and may provide a reliable scientific support for the prevention of heavy metal contamination in mine environments.

Distribution Pattern of Heavy Metals in the Surface Sediments of the Jiaozhou Bay

Grain size analysis and chemical analysis of heavy metals are made for 312 surface samples of the Jiaozhou Bay. Nineteen samples of the waste water taken from the sewage discharge outlets along the eastern coast of the bay are also analyzed for heavy metals. Results show that heavy metals are richer in the east and poorer in the west of the bay. Sedimentary dynamic studies reveal that the distribution of heavy metals in the surface sediments of the Jiaozhou Bay is under the control of hydrodynamics.

Self-Healing Liquid Metal Magnetic Hydrogels for Smart Feedback Sensors and High-Performance Electromagnetic Shielding

Hydrogels exhibit potential applications in smart wearable devices because of their exceptional sensitivity to various external stimuli.However,their applications are limited by challenges in terms of issues in biocompatibility,custom shape,and self-healing.Herein,a conductive,stretchable,adaptable,self-healing,and biocompatible liquid metal GaInSn/Ni-based composite hydrogel is developed by incorporating a magnetic liquid metal into the hydrogel framework through crosslinking polyvinyl alcohol(PVA)with sodium tetraborate.The excellent stretchability and fast self-healing capability of the PVA/liquid metal hydrogel are derived from its abundant hydrogen binding sites and liquid metal fusion.Significantly,owing to the magnetic constituent,the PVA/liquid metal hydrogel can be guided remotely using an external magnetic field to a specific position to repair the broken wires with no need for manual operation.The composite hydrogel also exhibits sensitive deformation responses and can be used as a strain sensor to monitor various body motions.Additionally,the multifunctional hydrogel displays absorption-dominated electromagnetic interference(EMI)shielding properties.The total shielding performance of the composite hydrogel increases to~62.5 dB from~31.8 dB of the pure PVA hydrogel at the thickness of 3.0 mm.The proposed bioinspired multifunctional magnetic hydrogel demonstrates substantial application potential in the field of intelligent wearable devices.

Self-organized pattern on the surface of a metal anode in low-pressure DC discharge

Self-organization phenomena on the surface of a metal electrode in low-pressure DC discharge is studied. In this paper, we carry out laboratory investigations of self-organization in a lowpressure test platform for 100–200 mm rod-plane gaps with a needle tip, conical tip and hemispherical tip within 1–10 k Pa. The factors influencing the pattern profile are the pressure value, gap length and shape of the electrode, and a variety of pattern structures are observed by changing these factors. With increasing pressure, first the pattern diameter increases and then decreases. With the needle tip, layer structure, single-ring structure and double-ring structure are displayed successively with increasing pressure. With the conical tip, the ring-like structure gradually forms separate spots with increasing pressure. With the hemispherical tip, there are anode spots inside the ring structure. With the increase of gap length, the diameter of the selforganized pattern increases and the profile of the pattern changes. The development process of the pattern contains three key stages： pattern enlargement, pattern stabilization and pattern shrink.

Bayesian decision-based pattern recognition on spectrum signal of metal transfer modes

A software system of pattern recognition on spectrum signal of metal transfer mode has been developed using Visual Basic under Windows environment. On the basis of the coincidence relation between the spectrum signal and metal transfer mode, according to the geometrical pattern feature of the spectrum signal, several key characteristic parameters are extracted. The correspondent recognition function and a minimum distance classifier have been constructed based on Bayesian decision theory. The results show that using this system, the metal transfer mode of MIG, MAG, CO2 welding can be recognized automatically which provides the basis for automatically controlling of the metal gas arc welding metal transfer.

Evaluation of the Marginal Adaptation in Metal Crowns Using CAD/CAM and Manual Wax Patterns

The aim of this study is to evaluate the maximum and minimum distances between the model and the cast crown of three techniques using Scanning Electron Microscopy (SEM). Three technique groups were used for this study: group A (control), traditional manual wax patterns;group B, dipping wax patterns;group C, resin patterns made with CAD/CAM. For each group, 10 samples were made using the same model, and then metal cast. Marginal accuracies of the samples were evaluated by performing gap measurements using SEM with a magnification of 1200× (minimum distance). The data were statistically analyzed using the one-way analysis of variance (ANOVA) at the 0.05 significance level. The average (standard deviation) of the minimum distance [μm] was 22.5 (12.1), 9.9 (4.3), and 14.7 (6.6), in groups A, B, and C, respectively. The average standard deviation of gap area [μm2] was 21667.2 (3476.4), 9906.4 (1512.1), and 16048.8 (8123). In the minimum distance comparison, groups A and B (p = 0.006) showed statistically significant results. In the gap area comparison, there was no statistical significance among groups A, B, and C (p = 0.174). The marginal adaptations of all three techniques were within a reported clinically acceptable range of margin.

Reconstruction Parameters of Local Scattering Sources of a Metallic Strip from the Backscattering Pattern

In this paper, it is proved the ability of quantity reconstruction, amplitudes and coordinates of metallic strip local scattering sources from the backscattering pattern. They are performed as the results of numerical solution for the infinite perfect conducting strip in case of E-polarization of the incident plane electromagnetic wave. In this case it is necessary to fulfill the following conditions. The local sources amplitudes should be the same order, in transverse and longitudinal directions the local sources should be separated into distances more than apparatus resolution, and the object maximum size does not have to be more than approximately 50λ. It was shown the limit and ability of the further development of the offered method.

The Morphology of Patterning with Pseudoplastic Metal Nanoparticle Fluids during Heat Treatment

A pseudoplastic metal nanoparticle fluid （PMNF） is used in nanoimprint to fabricate semiconductors and func- tional devices. The evaporation of the solvent and the sintering of the Au PMNF are investigated. The key parameters, which influence the morphology of patterning, such as the radius of metal particles, the concentra- tion of metal particles, the Hamaker constant of the solvent, viscosity of the fluids and the evaporation velocity, are analyzed. Based on a two-sphere sintering model, the equations are derived, which represent the relationships between the relative shrinkage and radius of the metal particles, sintering temperature and time. The optimal parameters for the heat treatment are provided in nanoimprint.

MXene ink hosting zinc anode for high performance aqueous zinc metal batteries

Despite the safety,low cost,and high theoretical capacity(820 mA h g^(-1))of Zn metal anodes,the practical application of aqueous Zn metal batteries remains a critical challenge due to the Zn dendrite growth,corrosion,and hydrogen evolution reaction.Herein,we demonstrate the MXene ink hosting Zn metal anodes(MX@Zn)for high-performance and patternable Zn metal full batteries.The as-designed MX@Zn electrode is more facile and reversible than bare Zn and CC@Zn,as verified by better cyclic stability and lower overpotentials of symmetric cells with the plating capacity of 0.05 mA h cm^(-2)at 0.1 m A cm^(-2)and of 1 m A h cm^(-2)at 1 m A cm^(-2).The MX@Zn|MnO_(2)full cells deliver a high specific capacity of 281.9 m A h g^(-1),91.5%of the theoretical capacity,achieving 50%capacity retention from 60 mA g^(-1)to 300 mA g^(-1)and 79.7%of initial capacity after 200 cycles.Moreover,the patterned devices based on the MX@Zn electrode achieve high energy and power densities of 348.57 Wh kg^(-1)and 1556 W kg^(-1),respectively,along with a capacity retention of 64%and Coulombic efficiency of 99%over 500 cycles.The high performance of MX@Zn is attributed to the high electrical conductivity and hydrophilicity of MXene and rapid ion diffusion through the 3D interconnected porous channels.

Melting of electronic/excitonic crystals in 2D semiconductor moirépatterns:A perspective from the Lindemann criterion

Using the Lindemann criterion,we analyzed the quantum and thermal melting of electronic/excitonic crystals recently discovered in two-dimensional(2D)semiconductor moirépatterns.We show that the finite 2D screening of the atomically thin material can suppress(enhance)the inter-site Coulomb(dipolar)interaction strength,thus inhibits(facilitates)the formation of the electronic(excitonic)crystal.Meanwhile,a strong enough moiréconfinement is found to be essential for realizing the crystal phase with a wavelength near 10 nm or shorter.From the calculated Lindemann ratio which quantifies the fluctuation of the site displacement,we estimate that the crystal will melt into a liquid above a critical temperature ranging from several tens Kelvin to above 100 K(depending on the system parameters).

全球镉资源现状与贸易格局分析

镉作为一种稀散金属,既是传统工业中重要的原料,又是对战略新兴产业发展至关重要的新型材料。本文围绕全球镉资源的分布、生产、消费、价格及回收利用等基本情况进行了论述,并采用复杂网络方法探讨了全球镉资源贸易格局。研究发现全球镉储量和产量虽然分布集中,但储产分离现象较为显著,中国在全球镉储量和产量方面占据首位。全球镉产量受环境保护政策的影响增速缓慢,作为全球第一产镉大国,近年来中国镉产量占全球产量的40%左右。全球镉消费结构从电池、颜料、稳定剂、涂料等传统领域向珠宝合金、太阳能薄膜、红外设备和核工业等战略新兴产业延伸。消费国家也从比利时、日本等发达国家向印度、中国转移,近年来中国镉消费量一直位居全球首位。镉价格近年来逐步上涨,主要受碲化镉太阳能电池等战略新兴产业需求增加的影响。尽管镍镉电池的回收率较高,但随着替代品的出现,部分镉产品可能会从回收循环中消失。受其环境污染特性的限制,预计未来镉在传统领域的消费占比将进一步降低。全球参与镉贸易的国家呈下降趋势,但处于网络之中的贸易量相对增加,主要进出口国家集中度较高。贸易地位从比利时、法国、中国、德国等国家逐渐向中国、韩国、日本、印度等亚洲国家转变,其中印度作为新兴的镉贸易国,对全球镉贸易格局将产生重要影响。

全球金属镓、锗贸易网络格局演变与供应危机传播研究

镓和锗是广泛应用于高新技术领域的重要战略资源。为了估测原产地发生供应危机对全球各国造成的影响,选取了2002—2022年金属镓、锗的贸易数据,运用贸易网络分析方法探究全球金属镓、锗贸易网络格局演变;建立级联失效(雪崩)模型,确立参数r_(1)=r_(2)=7,模拟2022年不同爆发源供应危机传播状况。研究发现:从全球贸易格局演变来看,金属镓、锗贸易规模和贸易平均度上升,亚洲国家与美国的贸易依赖关系有所减弱,南美洲对美国消费市场的贸易依赖指数增强;从网络供应危机传播来看,中国危机传播规模最大,传播轮次最多,美国和德国次之;在未锻轧金属镓、锗产品的贸易中,美国不会受中国供应危机的直接影响,而是通过比利时和瑞士受到间接影响。

基于取向纤维基底和图案化双相金属层的高灵敏应变传感器

为了提高液态金属基应变传感器的灵敏度,研究了一种高灵敏度、可拉伸的应变传感器,该传感器由取向的静电纺热塑性聚氨酯纤维基底和图案化双相金属传感层构成。以液态金属Galinstan为“岛”,固体金属银为“海”,构建了图案化双相金属传感层。银“海”可阻止连续的液态金属导电路径的形成,基于银导电区域的裂纹扩展机制,传感器的灵敏度显著提高。此外,纤维取向(水平或垂直)削弱了在受力时纤维的重新排列,增强了传感层的变形。结果表明,对于单一液态金属层或Ag层组成的传感器,基底纤维垂直取向与随机排列比较,灵敏度分别提高1.09倍和33.19倍。最终制成的基于垂直取向纤维基底和图案化双相金属层的应变传感器具有超高的灵敏度(灵敏度系数高达952.20)和宽传感范围(高达59.33%)。这种设计有望在可穿戴设备中显示良好的应用潜力。

黔西上二叠统煤系关键金属富集层时空分布及地质控制因素

黔西晚二叠世煤系关键金属元素富集层在垂向上叠置分布,但其在地层中的时空分布规律尚不清楚。详细研究关键金属富集层的时空分布规律可以预测其分布特征及了解该时期富集成矿规律与地质事件的联系。本文分析了煤系关键金属富集层的地球化学特征及垂向分布规律,探讨了其形成的地质控制因素。结果表明煤系Ga-Zr-Nb-REY关键金属富集层为自然伽马高异常岩层,具有低Sr/Ba、较高的Rb/Sr和CIAcorr值,以及相对较高的V/Ni和V/(V+Ni),表明在气候相对炎热、海平面仍相对较低时期形成于水体相对较深的缺氧环境中。根据富集层垂向分布特征总结了6种Ga-Zr-Nb-REY富集层沉积序列及3种Li富集层沉积序列,其中Ga-Zr-Nb-REY富集层垂向分布特征表明富集层在沉积旋回内处于相对一致的层位。M2井长兴组的Li富集层在垂向上有显著的旋回性。Ga-Zr-Nb-REY关键金属富集层为含板内火山灰层,其垂向叠置规律及关键金属元素含量受板内火山活动规律及强度控制。古地理格局控制了沉积物在地表遭受淋滤作用的强度,经历较弱或未经历淋滤作用的含板内火山灰层具有关键金属元素富集的特征。弱水动力条件利于火山灰的保存,局限环境可能是形成Li富集层的重要原因。在热液流体的影响下形成了黔西地区偶现的Li、Ti富集层。这种富集成矿规律及分布模式可以有效地预测关键金属元素富集层位的时空分布规律。

一种基于正面对准的CMUT制备工艺

基于晶圆键合的电容式微机械超声换能器(CMUT)制备工艺凭借其对膜厚控制度高、制备过程简单且良品率高等优势,是当前CMUT的主要制备工艺之一。分析了上电极位置准确性对CMUT发射声压的影响,结合薄膜透光率和光刻机正面对准精度高的特点,提出了一种基于正面对准的CMUT制备工艺并完成了CMUT阵列的制备。制备过程中通过两种开窗工艺获得正面对准标记,通过正面对准的方式实现上电极金属图形化,提高了上电极金属制备的可重复性和准确性。挑选制备好的CMUT阵列进行了一致性测试,经测试其接收灵敏度在-207.30~-208.01 dB以内,表明基于此工艺制备的CMUT阵列具有很好的一致性,为后续大规模批量制备用于无损检测和超声医疗成像的CMUT器件奠定了基础。

Fabrication of patterned transparent conductive glass via laser metal transfer for efficient electrical heating and antibacteria

Vapor deposition and three-dimensional(3D)printing technology are considered to be conventional methods to achieve patterned metal film preparation through the assistance of masks and high temperature.Therefore,there are still some challenges in fabricating metal films in template-free and normal temperature environment.In this work,we report a flexible and rapid laser metal transfer(LMT)technique for fabricating the various metal films(Cu,Ni,Sn,Al,Fe,and Ag)with different patterns without templates on arbitrary substrates(glass,polyimide(PI)films,and aluminum nitride(AlN)ceramic).Especially,the obtained transparent conductive glass displays high transmittance(more than 90%)and adjustable resistances(≈5Ω).According to the Joule effect,the interface resistance between Cu particles and copper oxide coating produces the high temperature approximately 280℃ at 2 V in a short time(≈60 s)and remains stable at 120℃ over 12 h.At last,the multifunctional glass with Cu patterns also shows excellent bactericidal activity(≈95%).This work demonstrates that laser metal transfer is an exceeding effective means of fabricating the micro/nano structures with potential applications in functional devices.

新疆大南湖煤田一井田煤中镓锗元素富集机理研究

大南湖煤田是我国重要的大型煤田,前人研究中发现大南湖煤田煤中关键金属有富集潜力,通过系统收集、梳理煤中关键金属方面的研究成果,结合部分测试数据,阐述了煤中镓、锗等关键金属元素在大南湖煤田的分布及富集机理,镓、锗元素均表现为顶底板含量较低,在中部煤层富集的现象。分析煤中镓锗含量与灰分产率、煤灰中Al_(2)O_(3)和Fe_(2)O_(3)的关系,认为研究区镓元素为无机矿物和有机质共同作用的复合成因,锗元素应当为风化搬运或地下水动力搬运周边物源进而形成,推测大南湖煤田中镓锗主要来自于南部的觉罗塔格造山带。

基于粒子群优化深度置信网络的气体绝缘金属封闭开关设备局部放电模式识别

气体绝缘金属封闭开关设备(gas insulated metal-enclosed switchgear,GIS)局部放电模式识别是其绝缘缺陷诊断和状态评估的重要部分,为实现放电类型的准确识别,提出了一种基于粒子群优化(particle swarm optimization,PSO)深度置信网络(deep belief network,DBN)的局部放电模式识别方法。该方法通过PSO算法对DBN网络的权值参数进行优化,提高网络对局部放电特征的学习能力。首先,选取现场多平台的4种GIS局部放电类型监测数据组成样本集,用于对所提方法进行分析;其次,用改进的PSO算法结合样本数据确定DBN网络的初始最优权值参数,建立初始DBN网络;然后,利用训练样本对初始DBN网络进行训练,得到局部放电识别模型。最后,基于渤海油田岸电海上动力平台GIS的局部放电数据,采用多种不同局部放电识别模型对数据样本进行算例分析,结果表明:所提的PSO-DBN模型可有效识别GIS设备局部放电类型,相较于传统的DBN网络、多层前馈神经网络(back propagation,BP)、支持向量机(support vector machine,SVM)和卷积神经网络(convolutional neural networks,CNN)具有更高的准确识别率。

基于模式识别的X射线荧光光谱法用于土壤重金属快速检测

土壤重金属的现场快速准确检测是实现土壤重金属污染防治的关键,便携式X射线荧光光谱仪可实现土壤中典型重金属的现场无损快速检测,且具有操作简单和无需消解处理的优势。基于该设备的X射线荧光光谱重金属分析方法受土壤基体效应影响严重,导致其检测准确度受限,需通过基体相似的标准样品进行校正,故将基于模式识别的基体成分分类方法和标准曲线法相结合,实现对土壤中典型重金属的精准分析。以我国砖红壤、水稻土、黑土、潮土、黄棕壤和黄红壤等6种典型土壤的X射线荧光光谱和重金属含量为数据集,采用5点3次窗口平滑、最大最小值归一化方法和主成分分析(PCA)对光谱数据进行处理,以PCA降维后的前5个主成分作为输入特征变量,土壤类别为标签,建立基于径向基函数(RBF)的支持向量机(SVM)模式识别模型,实现基体成分的相似性分类,模型的超参数优化采用角蜥蜴优化算法,优化后的核参数g为0.0381,惩罚因子c为7.8529,此时5折交叉验证正确率为100%。定量方法为标准曲线法,6类土壤中Cr的相关系数为0.9947~0.9993,Ni的相关系数为0.9868~0.9994,Cu的相关系数为0.9929~0.9999,Zn的相关系数为0.9841~0.9998,Pb的相关系数为0.9877~0.9996,As&Pb的相关系数为0.9613~0.9995,在同一基体下,重金属线性关系较佳。采用建立RBF-SVM模式识别模型对预测集24个样品进行预测,预测结果表明6类土壤的分类正确率为100%,未出现错误分类。根据分类结果,选择对应的标准曲线进行定量分析。结果表明Cr、Ni、Cu、Zn、Pb和As的预测平均相对误差分别为2.24%、3.66%、2.72%、2.15%、2.13%和5.55%,均低于6%。说明RBF-SVM模型结合标准曲线法对土壤中典型重金属的快速检测具有很好的适用性,有望用于实际土壤典型重金属的快速定量分析与检测。