Influence of lanthanum on enhancement of mechanical and electrical properties of Cu-Al_2O_3 composites

Two kinds of Cu-Al_2O_3 composites(with and without La) were prepared via mechanical alloying-spark plasma sintering(MA-SPS) method. Microstructure, mechanical properties and electrical resistivity were investigated systematically using metallography, scanning electron microscopy, transmission electron microscopy, mechanical and electrical properties testing. The results indicate that an appropriate amount of La can homogenize the distribution of Al_2O_3. As such, yield strength, ultimate tensile strength and elongation of Cu-Al_2O_3-La are greatly increased. Some semi-coherent interface between Cu and Al_2O_3 is found, which means a low interface energy. The grain shape of Cu changes to irregular band with the addition of La. This change results in a density decrease of grain boundary and reduces electrical resistance. Lanthanum may exist in the form of La_2O_3.     

Influence of TiN dopant on microstructure of TiB2 ceramic sintered by spark plasma

In this study, the impact of TiN as a sintering aid on the relative density and microstructure of TiB₂ ceramic was investigated. Monolithic TiB₂ and TiB₂ doped with 5?wt% TiN were sintered at 1900?°C for 7?min dwell time under the pressure of 40?MPa by spark plasma. The addition of TiN affected the microstructure of TiB₂-based sample considerably depicting the finer grains in the as-sintered ceramic. X-ray diffraction evaluation indicated that no interaction occurred between the initial materials. However, detail investigation by the map analysis and energy dispersive spectroscopy results revealed the formation of in-situ nano-sized hBN secondary phase in the TiN-doped TiB₂. In addition, TiN played a remarkable role on increasing the relative density of TiN-doped TiB₂ ceramic producing a nearly fully dense ceramic with relative density of 99.9% in comparison with the monolithic ceramic having 96.7% relative density.     

电感耦合等离子体原子发射光谱法测定钒钛磁铁矿中锌

钒钛磁铁矿中含有一定量的锌,在高炉冶炼过程中,锌被还原成金属锌,而金属锌会侵蚀炉体的耐火材料,因此在钒钛磁铁矿冶炼中锌是一种有害元素,需要对进入炉体中锌的含量进行严格控制。试样采用盐酸-硝酸-氢氟酸-高氯酸体系溶解,选择Zn 206.200nm作为分析谱线,采用基体匹配法绘制校准曲线消除基体效应的影响,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钒钛磁铁矿中锌。锌含量为0.01%~0.05%(质量分数)时与其发射强度呈线性,相关系数为0.9999;方法检出限为0.0030μg/mL。按照实验方法测定两个钒钛磁铁矿样品中锌,结果的相对标准偏差(RSD,n=10)小于1%;加标回收率为98%~102%。     

电感耦合等离子体原子发射光谱法在钒钛磁铁矿中钒化学物相分析中的应用

钒钛磁铁矿中钒的化学物相分析一般测定硫化物中钒、钛磁铁矿中钒、硅酸盐中钒和钛铁矿中钒共4项。其中硫化物中钒利用强氧化剂分离,钛磁铁矿中钒利用其强磁性磁选分离,硅酸盐中钒利用氟化铵-硝酸分离,最后从残渣中得到钛铁矿中钒,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钒。试验对钒钛磁铁矿中钒的相态划分进行了统一,对各相态浸取溶剂进行选择及优化,确定分析谱线并计算检出限。按照实验方法测定3个矿区钒钛磁铁矿中总量钒和各相态钒,总量钒和钛磁铁矿中钒的测定结果与分光光度法测定值相一致;各相态钒测定结果的相对标准偏差(RSD,n=12)大部分在5%以内。各相态钒加和与总量钒进行比较,相对偏差在5%以内,满足《地质矿产实验室测试质量管理规范》要求。     

电感耦合等离子体原子发射光谱法测定钛及钛合金中铬和铜

铬、铜含量影响钛及钛合金组织结构和性能,须对其准确测定。采用硫酸-硝酸溶样体系溶解样品,选择Cr 267.716nm、Cu 327.393nm为分析线并采用两点校正法扣除背景,使用钛基体匹配的方法绘制校准曲线,使用电感耦合等离子体原子发射光谱法(ICP-AES)测定钛及钛合金中铬和铜。方法中各元素校准曲线线性良好,相关系数均大于0.999;检出限为0.04~6.0μg/g。按照实验方法测定3个钛及钛合金样品中铬和铜,结果的相对标准偏差(RSD,n=10)小于5%。按照实验方法测定5个钛合金标准物质中铬和铜,测定结果与认定值相吻合,分析误差在实验室允许的误差范围内。     

Cathode plasma electrolytic deposition of Al2O3 coatings doped with SiC particles

Semiconductor particles doped Al₂O₃ coatings were prepared by cathode plasma electrolytic deposition in Al(NO₃)₃ electrolyte dispersed with SiC micro- and nano-particles (average particle sizes of 0.5–1.7?µm and 40?nm respectively). The effects of the concentrations and particle sizes of the SiC on the microstructures and tribological performances of the composite coatings were studied. In comparison with the case of dispersing with SiC microparticles, the dispersion of SiC nanoparticles in the coatings was more uniform. When the concentration of SiC nanoparticles was 5?g/L, the surface roughness of the composite coating was reduced by 63%, compared with that of the unmodified coating. Friction results demonstrated that the addition of 5?g/L SiC nanoparticles reduced the friction coefficient from 0.60 to 0.38 and decreased the wear volume under dry friction. The current density and bath voltage were measured to analyze the effects of SiC particles on the deposition process. The results showed that the SiC particles could alter the electrical behavior of the coatings during the deposition process, weaken the bombardment of the plasma, and improve the structures of the coatings.     

电感耦合等离子体原子发射光谱法测定土壤中8种组分

为满足土地质量调查的需求,实现土壤中多组分的同时消解及准确测定,提高大批量样品的分析效率,建立了土壤样品经高压密闭消解后,采用电感耦合等离子体原子发射光谱法(ICP-AES)测定K₂O、Na₂O、CaO、MgO、Ba、Mn、Cu、Zn的方法。通过对消解体系、酸用量、消解温度等方面的考察,确定最佳实验条件;并对待测液中共存元素Al、Fe的干扰进行探讨,两者均不干扰测定。各组分校准曲线线性相关系数均大于0.999;检出限为0.01~10μg/g。实验方法用于测定土壤标准样品GBW07385、GBW07386、GBW07388中K₂O、Na₂O、CaO、MgO、Ba、Mn、Cu、Zn,测定结果的相对标准偏差(RSD,n=12)为1.1%~4.3%,相对误差RE为-4.0%~4.6%。采用实验方法对土壤实际样品中K₂O、Na₂O、CaO、MgO、Ba、Mn、Cu、Zn进行测定,结果的RSD(n=6)为1.2%~4.6%;并与地矿行业标准方法DZ/T 0279.2—2016测定结果进行比对,测得结果基本一致。     

Cold plasma processing of milk and dairy products

BackgroundThermal pasteurization and sterilization are predominantly used in the dairy industry due to their efficacy in improving the product safety and shelf life. However, heat treatment can cause undesirable protein denaturation, non-enzymatic browning, loss of vitamins and volatile flavor compounds, freezing point depression, and flavour changes. Cold plasma is a non-thermal technology that has gained attention in recent years as a potential alternative method for chemical and thermal disinfection in foods using ambient or moderate temperatures and short treatment times.Scope and approachThis review aims to describe the fundamentals, parameters, and technology on cold plasma, discussing the critical processing factors involved in this technology. Also, it describes the mechanisms of microbial inactivation and provides an overview of the effects of non-thermal plasma on the quality of dairy products, considering a physicochemical, sensory and microbiology perspective.Key findings and conclusionsCold plasma uses less aggressive mechanisms of action to the milk matrix when compared to the techniques currently used, and has shown an excellent performance on the elimination of pathogenic and spoilage microorganisms besides maintaining, in many cases, the nutritional, functional, and sensory characteristics of the product.     

Embedded Metal Oxide Plasmonics Using Local Plasma Oxidation of AZO for Planar Metasurfaces

New methods for achieving high-quality conducting oxide metasurfaces are of great importance for a range of emerging applications from infrared thermal control coatings to epsilon-near-zero nonlinear optics. This work demonstrates the viability of plasma patterning as a technique to selectively and locally modulate the carrier density in planar Al-doped ZnO (AZO) metasurfaces without any associated topographical surface profile. This technique stands in strong contrast to conventional physical patterning which results in nonplanar textured surfaces. The approach can open up a new route to form novel photonic devices with planar metasurfaces, for example, antireflective coatings and multi-layer devices. To demonstrate the performance of the carrier-modulated AZO metasurfaces, two types of devices are realized using the demonstrated plasma patterning. A metasurface optical solar reflector is shown to produce infrared emissivity equivalent to a conventional etched design. Second, a multiband metasurface is achieved by integrating a Au visible-range metasurface on top of the planar AZO infrared metasurface. Independent control of spectral bands without significant cross-talk between infrared and visible functionalities is achieved. Local carrier tuning of conducting oxide films offers a conceptually new approach for oxide-based photonics and nanoelectronics and opens up new routes for integrated planar metasurfaces in optical technology.     

Growth Performance,Carcass Characteristics,Fatty Acid Composition,and Blood Biochemical Parameters of Lamb Fed Diet with the Addition of Lingonberry Leaves and Oak Bark

The aim of the study is to determine the effect of natural additives supplemented to the lamb diet on lamb performance, fatty acid (FA) composition of edible parts of lambs, and biochemical plasma indices. The study is carried out on 18 male lambs, allocated to three groups in a randomized complete block design. Control animals (CON) are fed a basic diet, while the experimental lambs additionally receive lingonberry leaves (VVI) or oak bark (QUE) (10 g d^?1), as a different source of tannins. Supplementing lambs with the VVI diet decreases fat content in the longissimus dorsi muscle (MLD). The VVI diet decreases monounsaturated fatty acid (MUFA) concentration (including C18:1 cis‐9) in the MLD, increases the proportion of C16:0, C16:1, C17:1, and C22:6 n‐3 in the semitendinosus muscle, as well as increases the n‐6/n‐3 ratio and thrombogenic index in the liver. The addition of QUE to lamb diets decreases C17:1 concentration and increases the content of C18:1 trans‐11 in the MLD. Tannins‐enriched diets increase low density lipoprotein concentrations in the blood plasma. The VVI diet increases the activity of alkaline phosphatase, while QUE supplementation decreases gamma‐glutamyl transferase activity in blood plasma. Modifications of FA composition in lamb tissues may suggest an indirect effect of tannins on FA ruminal biohydrogenation. Practical Applications: The use of VVI and QUE in lamb nutrition as natural resources is of a great interest to scientists. The present study shows that primarily VVI addition to lamb diets affects the quality of meat, due to higher proportion of catechin than QUE. Decreased concentration of fat, as well as increased proportion of C22:6 n‐3 and desirable fatty acids (including MUFA, polyunsaturated fatty acid, C18:0) after VVI supplementation increases health‐promoting properties of lamb meat and is related to humans. However, the presence of biologically active substances (tannins) in the examined additives makes it necessary to further research and discover their full potential in many areas.