Palladium-assisted Metal Patterning on Polyimide Surfaces

A novel method of patterning high precision copper conductive micropatterns on flexible polymer substrate(polyimide)is developed.We utilized the coordination effect between palladium salts and pyridine structures to fix the palladium chloride(PdCl_(2))on the surface of polymer film while the 2,6-dimethylpyridine structures formed in the specific areas under ultraviolet light guaranteed the resolution of final patterns.Simultaneous thermal reduction of PdCl_(2) on the surface can be achieved in the process of thermal cyclization of the polymer substrate.As a consequence,the obtained polyimide(PI)film can be patterned with conductive copper micropatterns directly by electroless plating.In particular,we accomplished the deposition of high precision copper pattern with a minimum line width of 50μm and minimum line spacing of 20μm on PI thin films(thickness~10μm)by electroless plating.The prepared conductive copper micropatterns exhibit a low resistivity of 1.78μΩ·cm the same as the pure block copper.And the relationship between the structures of the polymer chains and the physical properties of polymer substrates,such as the dimensional stability,mechanical and dielectric properties were also discussed in detail.This simple and novel method of patterning metal on the polymer surface does not need to achieve the catalytic metal adhesion required for electroless plating at the cost of destroying the substrate surface and avoiding the introduction of unstable interlayers.This patterning method is compatible with the current roll-to-roll production process and can be used to develop high-performance micro-integrated circuits.

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-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.

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.

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.

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.

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。

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。

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.

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。

禹州煤田煤下铝本溪组铝土矿伴生关键金属研究

通过对河南省禹州煤田煤下铝预、普、详查三个阶段的勘查,发现铝土矿中广泛富集锂、镓、稀土等关键金属,通过对神垕-梁北矿段IZK17012钻孔本溪组地层重采样和分析,对本溪组含铝岩系的地质特征及其中富集的关键金属研究,总结了关键金属的富集特征。研究结果表明,关键金属Li、Ga、W、U和REE表现出不同程度的富集,指示不同类型的铝土岩均具有较大的资源潜力和经济价值。总体而言,禹州煤田本溪组含铝岩系中关键金属Li、Ga、W、U、REE的资源潜力及潜在经济价值巨大,后续应加强铝土矿综合利用,提高其综合利用率,实现铝土矿中伴生关键金属的系统评价及开发利用。

金属地质矿产勘查中的区域成矿规律研究

随着全球经济的不断发展和各国工业化水平的提高,金属矿产资源需求正在日益增长。为了满足不断增长的资源需求,全球范围内的金属地质勘查工作正在广泛开展,以寻找更多的潜在矿产资源。区域成矿规律研究是金属地质勘查中至关重要的环节之一,对于找矿突破、提高资源勘查效率具有重要意义。

基于物质来源解析的汕头市土壤重金属环境容量研究

大多数研究评价土壤环境容量时忽略了重金属来源的影响,而基于物质来源解析探讨土壤重金属环境容量,能更好地评估区域环境容量特征及其动态变化原因,对有效防控、预警和治理重金属污染具有重要意义。汕头市是广东省的经济特区之一,拥有较高的工业化和城市化水平,土壤重金属污染不容忽视,而目前区域环境容量状况尚不明确。因此本研究以汕头市表层土壤为研究对象,采集了511件土壤样品,以进行土壤环境容量研究。基于GIS技术和地统计学方法,我们采用富集因子法评估研究区土壤重金属富集程度,运用主成分分析和相关性分析方法判断土壤重金属来源,根据综合指数法分析土壤重金属的环境容量特征以及各环境容量指数空间分布规律。结果表明:汕头市表层土壤As、Cd、Cr、Cu、Hg、Ni、Pb和Zn的含量分别为4.84(0.23~119.4)、0.14(0.013~4.94)、36.05(2.2~109.1)、19.08(2.9~453.1)、0.18(0.008~1.394)、13.29(3.7~229.6)、51.73(9.9~1000)和79.83(9.2~309.5)mg/kg。除土壤Pb整体为中度富集,研究区其他土壤重金属整体为轻度富集。主成分分析结果表明:5个主成分来源分别为自然和农业混合源、农业和工业混合源、工业来源、采矿来源和石材开采来源。土壤重金属静态环境容量大小排序为Zn>Cr>Ni>Pb>Cu>As>Hg>Cd。土壤重金属综合环境容量为中等容量水平,受地质背景的影响,但盐鸿镇、贵屿镇和陈店镇等区域由于综合人类活动导致重金属环境容量普遍较低,存在一定风险。本研究结果可为汕头市预警和管控土壤重金属污染,修复和治理污染土壤,提高环境容量和土壤质量提供科学参考依据。

Effects of Land Use on Heavy Metal Accumulation in Soils and Sources Analysis

Heavy metal accumulation and its influential factors were studied in the different land use soils, which would provide a theoretical basis for controlling the content of heavy metals in soils. To identify the effects of land use on the accumulation of heavy metals in soils, 148 soil samples were collected from four land use patterns including greenhouse field, uncovered vegetable field, maize field, and forest field in Siping area of Jilin Province, China, and Cr, Ni, Cu, As, Cd, Pb, and Zn contents of those samples were determined with ICP and ICP-Mass. The result showed that there was a rather large difference in effects of the accumulation of Cr, Ni, Cu, As, Cd, and Zn in soils under different land use patterns, except Pb. Based on the assessment which compared with background concentrations in soil, the higher accumulation of heavy metals was found in greenhouse and uncovered vegetable field, much less in maize field and forest field. The mean contents of heavy metals in soils from high to low were arranged in order of greenhouse field, uncovered vegetable field, maize field, and forest field. Cd and Cu had relatively serious accumulation in soils compared to Cr, Ni, As, and Zn. The mean content of Cd in greenhouse field was 0.467 mg kg-x,which exceeded the grade II of the Chinese Soil Quality Criterion GB15618-1995 （6.5 〈pH〈7.5） for Cd standard of 0.3 mg kg^-1, while it was 5.2 times of Cd standard in the forest fields. The mean contents ofCr, Ni, Cu, As, Pb, and Zn in soils under four land use patterns were lower than the grade II of the Chinese Soil Quality Criterion. Compared with the soil cultivated years, the agricultural chemical compounds and manures application, especially the quality and quantity of applied fertilizer was one of the main reasons for leading to different accumulation of heavy metals in soils under the studied land use patterns. The accumulation of heavy metals, such as Cr, Ni, Cu, As, Cd, and Zn in soils was significantly affected by land use patterns, among them the accumulation of heavy metals in greenhouse soils was higher than others. It is suggested that the application of chemical fertilizer, organic fertilizer, and pesticides with high contents of heavy metals should be avoided to prevent the accumulation of heavy metal and keep high quality soils for sustainable use.

Plastic flow pattern and its effect in friction stir welding of A2024 and A1060

During the friction stir welding (FSW), the property of the welding joint is highly affected by the plastic and viscous flow behavior of the softened material. The flow pattern of the welded material was examined through observing the microstrucrural distribution of friction stir welded joints between dissimilar 2024 and 1060 aluminum alloy. The experimental results show that the flow patterns of material at different locations in the weld are different and can be divided into four layers along the thickness direction: surface flow layer influenced by the shoulder of the tool, in which the material tends to flow as integrity; horizontal flow layer influenced by the surface flow layer, in which the material of surface flow layer enters and flows forwards under the advancing force of the tool; vertical flow layer (plastic flow area induced by stirring of the pin), in which the flow pattern is complex and onion rings can often be observed; unstirred bottom layer because of the length of the pin being shorter than the thickness of the plates. The effect of plastic flow on welding quality was further investigated. The study suggests that welding quantity is significantly influenced by the flow pattern and defects always appear in horizontally lamellar flow region because of the complex flow pattern.

Effect of carbon addition on microstructure and mechanical properties of Ti-based bulk metallic glass forming alloys

A kind of novel Ti-based composites was developed by introducing different amounts of carbon element to the Ti50Cu23Ni20Sn7 bulk metallic glass forming alloys. The thermal stability and microstructural evolution of the composites were investigated. Room temperature compression tests reveal that the composite samples with 1% and 3%（mass fraction） carbon additions have higher fracture strength and obvious plastic strain of 2195MPa, 3.1% and 1913MPa, 1.3% respectively, compared with those of the corresponding carbon-free Ti50Ni20Cu23Sn7 alloys. The deformation mechanisms of the composites with improved mechanical properties were also discussed.

Charging for the waste dumping of open-pit metal mines

Based on the externality theory and the environmental value theory, the hypothesis of charging for waste dumping of open-pit metal mines was put forth. The charging methods were designed according to the characteristics of waste dumping of openpit metal mines, including charging based on the dumping amount of the total waste, multi-charging factors, exceeding standard punishment charging, and so on. The main charging parameter is based on the dumping area rather than the total amount of waste dumping. The charging model of waste dumping of open-pit mines was formulated, and the charging rate was divided into two parts, i.e., the standard charging rate and the differential charging rate. The standard charging rate was derived using the equilibrium dynamic model, whereas the differential one was obtained by establishing the fuzzy synthesized evaluation model.

Heavy Metals Contents of Municipal Solid Waste Dumpsites in Potiskum, Yobe State Nigeria

The concentrations of As, Cd, Cr, Cu, Ni, Pb, Fe and Zn in selected dumpsites in Potiskum were determined with Buck Scientific 210VGB Atomic Absorption Spectrometer (AAS) AVG 210. One-way ANOVA was deployed at p < 0.05 level of significance for obtained triplicate values. It was found that the concentration (mg·kg-1) of studied heavy metals in Potiskum dumpsites ranged from 0.108 ± 0.02 - 262.536 ± 0.68 with pattern of accumulation Pb (262.536 ± 0.02) > Zn (183.369 ± 0.58) > Fe (159.453 ± 0.50) > Cu (111.382 ± 0.62) > Cr (43.523 ± 0.36) > Ni (6.419 ± 0.26) > Cd (0.679 ± 0.01) > As (0.108 ± 0.02) mg·kg-1. The concentrations of As, Cr, Ni, Fe and Zn fell below the WHO standards while those of Pb, Cd and Cu were above set limits by WHO. High acidity corresponds markedly with high levels of Cd, Cu, Cr and Zn and requires urgent attention as this trend is capable of groundwater contamination that will cause public health concern in affected areas.

Effects of Planting Methods on Levels of Common Pesticides and Heavy Metals in Dendrobium officinale

The levels of common pesticides and heavy metals in Dendrobium officinale grown from 2012 to 2014 were measured, and three planting methods were used in 2014. The quality of plant husbandry improved during the study period. Thirteen types of pesticides were detected in D. officinale grown in 2014 and antimicrobials, including carbendazim, difenoconazole and azoxystrobin, were evident in 61.53% of plants. These three pesticides constituted 72.33% of all the antimicrobials detected. Planting methods affected the levels of pesticides and heavy metals. Trellising in plastic sheds was optimal, being associated with the lowest amounts of both pesticides and heavy metals. Both cadmium（Cd） and lead（Pb） levels were high in treed plants, whereas Cr, As and Cu levels were the highest in potted plants.