Effect of Sintering Temperature and Zinc Content on Some Properties of Li-Zn Ferrites

Li-Zn mixed ferrites with composition formula ZnxLi0.5-x/2Fe2.5-x/2O4 (0.2≤x≤0.8) were prepared by the usual ceramic method in 1000~1150℃. The effects of Zn substitution and sintering temperature on the formation, densification, microstructure and a.c. electrical conductivity have been studied. Under the effect of changing the firing temperature and Zn content, high sintered Li-Zn ferrite bodies are achieved. More fine structure bodies having high electrical resistance are obtained at high Zn content

Effect of zinc powder content on tribological behaviors of brake friction materials

Brake friction materials with different zinc powder contents(0,2,4,6,8 wt.%)were fabricated via powder metallurgy method.The results indicate that with the increasing zinc powder content,the density and thermal conductivity of the materials gradually increase,while the hardness decreases monotonously.With increasing zinc powder content,the curve of the nominal friction coefficient shows fluctuating trend but the lowest friction coefficient also shows an increase.However,the wear rate and braking noise of the friction material monotonously decrease with increasing zinc content.This effect may be attributed to the transformation of the tribological mechanism from adhesive wear and abrasive wear to adhesive wear.The brake friction material with 4 wt.%zinc powder exhibits both the best tribological and noise performance.

Effects of Different Nitrogen Fertilizer Levels and Native Soil Properties on Rice Grain Fe, Zn and Protein Contents

Deposition of protein and metal ions （Fe, Zn） in rice grains is a complex polygenic trait showing considerable environmental effect. To analyze the effect of nitrogen application levels and native soil properties on rice grain protein, iron （Fe） and zinc （Zn） contents, 32 rice genotypes were grown at three different locations each under 80 and 120 kg/hm2 nitrogen fertilizer applications. In treatments with nitrogen fertilizer application, the brown rice grain protein content （GPC） increased significantly （1.1% to 7.0%） under higher nitrogen fertilizer application （120 kg/hm2） whereas grain Fe/Zn contents showed non-significant effect of nitrogen application level, thus suggesting that the rate of uptake and translocation of macro-elements does not influence the uptake and translocation of micro-elements. The pH, organic matter content and inherent Fe/Zn levels of native soil showed significant effects on grain Fe and Zn contents of all the rice genotypes. Grain Zn content of almost all the tested rice genotypes was found to increase at Location III having loamy soil texture, neutral pH value （pH 6.83） and higher organic matter content than the other two locations （Locations I and II）, indicating significant influence of native soil properties on brown rice grain Zn content while grain Fe content showed significant genotype × environment interaction effect. Genotypic difference was found to be the most significant factor to affect grain Fe/Zn contents in all the tested rice genotypes, indicating that although native soil properties influence phyto-availability of micronutrients and consequently influencing absorption, translocation and grain deposition of Fe/Zn ions, yet genetic makeup of a plant determines its response to varied soil conditions and other external factors. Two indica rice genotypes R-RF-31 （27.62 μg/g grain Zn content and 7.80% GPC） and R1033-968-2-1 （30.05 μg/g grain Zn content and 8.47% GPC） were identified as high grain Zn and moderate GPC rice genotypes. These results indicate that soil property and organic matter content increase the availability of Fe and Zn in rhizosphere, which in turn enhances the uptake, translocation and redistribution of Fe/Zn into rice grains.

Reduced nitrogen availability during growth improves quality in red oak lettuce leaves by minimizing nitrate content, and increasing antioxidant capacity and leaf mineral content

Overuse of N in lettuce production can lead to environmental problems caused by leaching and the accumulation of harmful nitrates in edible tissues. This study investigated the effect of applied nitrogen (N) concentrations between 40 and 2400 mg·L–1 on growth, nitrate accumulation, mineral leaf content, and antioxidant capacity in Oak Leaf lettuce cv. “Shiraz” grown under hydroponic conditions in Australia. Yield (g FW) increased with nitrogen (N) application rate up to 1200 mg·L–1, as did leaf N content, while C:N declined. Nitrogen Utilization Efficiency (NUtE) increased rapidly from 40 to 75 mg·L–1 applied N, leveling at 150 mg·L–1 with no subsequent effect of N concentrations between 400 and 2400 mg·L–1. Nitrate content rose significantly with increased N, particularly at 1200 and 2400 mg·L–1. Leaf total plant phenolic content (TPP) and antioxidant capacity (measured by ferric reducing antioxidant power—FRAP) were both maximal at 75 and 400 mg·L–1 applied N, while highest oxygen radical absorption capacity (ORAC) values were found in leaves supplied with low N (40 to 400 mg·L–1). Applied N as calcium nitrate also significantly affected leaf mineral content as B, Mg, Mn, and Zn significantly decreased with increasing N. These results indicate that N applications of 1200 mg·L–1 or higher can result in reduced antioxidant capacity and mineral content in lettuce leaves.

Impact of Different Zinc Application Methods on Yield and Yield Components of Various Wheat (<i>Triticum aestivum</i>L.) Cultivars

To evaluate the impact of different zinc application methods on yield and yield components of various wheat cultivars, a field experiment was carried out at Student’s Farm, Department of Agronomy, University of Agriculture Faisalabad, during winter 2014-2015. The experiment was laid out in RCBD (Randomized Complete Block Design) with factorial arrangement. In this experiment, all the treatments were replicated three times, using the net plot size of 1.8 m × 5.0 m. The experiment comprised of two factors. Factor A consists of two varieties: Faisalabad-2008 and Punjab-2011. While, Factor B consists of different methods of zinc application, control, zinc application in soil before planting 23 kg·ha-1, zinc foliar application, 4% ZnSO4 solution at two stages (tillering and stem elongation stage). The data regarding different parameters were collected and analyzed from the crop using standard procedures. Regarding the impact of zinc application method maximum plant height at maturity (103.6 cm), total number of tillers (564.67 m-2), spike length (10.83 cm), number of spikelets spike-1 (19.50), number of grains spike-1 (50.36), 1000-grain weight (34.16 g), biological yield (11.93 t·ha-1), grain yield (6.00 t·ha-1) and harvest index (39.25%) were recorded in treatment where zinc was applied both in the soil before planting and by foliar application on later growth stages. Similarly, grain zinc contents (33.11 mg·kg-1), grain protein contents (10.1%) and grain carbohydrate contents (64.23%) were also observed in the treatment where zinc was applied both in the soil before planting and by foliar application on later growth stages, which is better than all other treatments. In case of wheat varieties, Faisalabad-2008 performed better than Punjab-2011, with maximum method maximum total number of tillers (460.67 m-2), spike length (9.70 cm), number of grains spike-1 (48.80), 1000-grain weight (33.81 g), biological yield (10.32 t·ha-1), grain yield (5.0 t·ha-1) and harvest index (33.93%). It is concluded that sowing of wheat cultivar Faisalabad-2008 + application of zinc in soil before planting with foliar application at later stages (tillering and stem elongation stage) of wheat could give better results in terms of yield.

用电位滴定法测定含锌硫化活性剂中锌含量

将含锌硫化活性剂直接溶解于盐酸溶液中,以乙二胺四乙酸二钠为滴定剂、铜离子选择电极为指示电极、银/氯化银为参比电极,采用电位滴定法测定含锌硫化活性剂中的锌含量。研究表明,硫酸铜的加入可增大滴定曲线的突跃范围,且铜离子选择电极在pH值为10的缓冲体系中灵敏度较高。采用电位滴定法测定2种含锌硫化活性剂中的锌离子含量及其回收率,并与原子发射光谱法进行比较,结果表明该两种硫化活性剂中锌离子含量回收率分别为100.13%和99.32%,且两种测试方法所得结果无明显差异,采用电位滴定法测定标准溶液中的锌离子含量并进行统计检验,结果显示测试值与标准值无明显差异,说明采用电位滴定法测定含锌硫化活性剂中锌含量可行有效。同时测定了混炼橡胶中硫化活性剂的锌离子含量,结果与理论计算值相近,故该方法同样适用于混炼橡胶中锌离子含量的测定。

络合滴定法测定复方乳酸依沙吖啶软膏中氧化锌的含量

目的:建立复方乳酸依沙吖啶软膏中氧化锌含量的测定方法。方法:采用络合滴定法对同一批次复方乳酸依沙吖啶软膏供试品进行氧化锌含量测定,对其专属性、线性范围、精密度、准确度实验结果进行数据分析,以判断方法的适用性。结果:本实验方法专属性良好,氧化锌在6.0~56.5 mg质量范围内线性关系良好,线性方程Y=0.245196X+0.050564(r=0.9994);氧化锌检出限为0.13 mg,定量限为0.43 mg;精密度实验氧化锌重复性实验相对标准偏差(RSD)为1.5%(n=6),氧化锌中间精密度RSD为1.3%(n=12);所有加标水平氧化锌平均回收率为100.3%(RSD=2.7%)。结论:该方法简单、快速,测定结果均符合《中华人民共和国药典》2020年版四部通则9101要求,适用于复方乳酸依沙吖啶软膏中氧化锌的含量测定。

叶面喷施锌肥对小豆产量及籽粒锌含量的影响

为促进黑龙江省小豆产业提质增效,以龙红豆4号和冀红352为试验材料,分别于2022和2023年进行硫酸锌施用浓度和施用次数效果试验。2022年,设置5个ZnSO4浓度(质量百分数为0%,0.1%,0.2%,0.3%和0.4%),在结荚期进行叶面喷施处理,研究其对小豆产量因子及籽粒锌含量的影响,并筛选出最佳施用浓度(0.3%)。2023年,在结荚初期、结荚中期、结荚初期+结荚中期,进行叶面喷施0.3%的ZnSO4筛选出最佳喷施次数。2年研究结果表明,喷施外源ZnSO4可提高小豆单株有效荚数、单株粒重和百粒重。喷施0.3%的硫酸锌最为适宜,能有效提高小豆百粒重和籽粒锌含量,分别较CK提高6.68%~9.97%和16.17%~25.33%;在结荚初期+结荚中期叶面喷施2次浓度为0.3%的外源ZnSO4可显著提高小豆籽粒锌含量,龙红豆4号和冀红352较对照分别提高33.33%和48.16%,喷施2次与喷施1次相比,显著提高了冀红352的单株产量。

内蒙古某含碳高硫锌锡矿石选矿试验研究

内蒙古某含碳高硫锌锡矿石锌品位1.02%、锡品位0.86%,硫和碳含量分别为14.02%、1.68%。矿石矿物组成较复杂,主要有用矿物为闪锌矿、锡石和黄铁矿,脉石矿物主要为石英、绿泥石和绢云母等。为确定矿石合理的开发利用工艺,采用预先脱碳—浮重联合工艺流程开展选矿试验研究。结果表明,矿石经预先脱碳、1粗1扫1精锌硫混选、1粗1扫3精锌硫分离浮选流程处理,闭路试验可得到Zn品位为45.16%、Zn回收率为71.19%的锌精矿,S品位为46.92%、S回收率81.91%的硫精矿;浮选尾矿采用摇床重选,经粗选、精选、复选和中矿再选,可获得Sn品位45.52%、Sn回收率81.99%的锡精矿,以及Sn品位3.13%、Sn回收率11.09%的锡中矿。所设计试验流程较好地解决了矿石中有机碳对浮选的不利影响,综合回收了有价矿物,可为同类矿石的开发利用提供理论借鉴。

火焰原子吸收光谱测定葡萄糖酸锌口服液中锌含量

“火焰原子吸收光谱”是本科生仪器分析实验教学中的重要实验之一。原子吸收光谱用于实际样品中某一特定元素的定量测定,具有测定准确度高、精密度高和选择性好等优点。葡萄糖酸锌口服液是生活中常见的口服补锌类非处方药,通过本科生自主实验,建立火焰原子吸收实验方法,测定葡萄糖酸锌口服液中锌含量,方法简便、易于操作。通过该自主实验,培养学生利用课堂所学理论知识解决实际问题的能力,实现“学以致用,用以促学”的育人目标。

兼顾江汉平原水稻产量和品质提高的优化施锌量研究

在大田条件下,以4个水稻品种(立香85、象牙香占、合两优927、昌两优8号)为试验材料,通过基施锌肥研究不同施锌量[0 kg/hm^(2)(CK)、7.5 kg/hm^(2)(Zn1)、15 kg/hm^(2)(Zn2)、30 kg/hm^(2)(Zn3)]下水稻产量、品质的变化,为江汉平原优质稻锌肥施用提供理论依据。结果表明,施锌可以显著提高水稻产量,且水稻产量随着施锌量的增加呈先上升后降低的趋势,总体上以Zn2处理最高,Zn1处理次之。立香85、合两优927、昌两优8号以Zn2处理产量最高;象牙香占以Zn1处理产量最高,Zn2处理次之。施锌处理产量较CK增加了8.1%~28.8%。施锌对稻米加工品质有明显的改善作用,整体以Zn1和Zn2处理下糙米率、精米率、整精米率较高。不同施锌处理下直链淀粉含量因品种而异,其中,立香85以Zn1处理最高,昌两优8号以Zn2处理最高,象牙香占和合两优927以Zn3处理最高。对于淀粉RVA谱特征值,立香85、象牙香占、昌两优8号均以Zn1处理崩解值最高;消减值表现为立香85和合两优927在CK下最低,象牙香占和昌两优8号在Zn1处理下最低。各品种粗蛋白含量随施锌量的增加呈先升高后降低的趋势,其中,立香85、合两优927均以Zn1处理粗蛋白含量最高,象牙香占和昌两优8号均以Zn2处理粗蛋白含量最高。总体上,清蛋白、球蛋白和醇溶蛋白含量均以Zn2处理最高,谷蛋白含量以Zn1处理最高。糙米、精米锌含量也随着施锌量的增加呈现先增加后降低的趋势。其中,立香85、合两优927均以Zn1处理糙米锌含量最高,分别为23.1、19.8 mg/kg;象牙香占和昌两优8号均以Zn2处理最高,分别为20.0、17.7mg/kg。各品种糙米锌含量均大于精米锌含量。综合水稻产量、品质等多方面因素来看,江汉平原施锌处理以Zn1—Zn2为优,施锌量为7.5~15 kg/hm^(2)。

EDTA滴定法准确测定钢铁除锈废酸中锌离子含量

针对钢铁除锈的废酸综合利用过程中锌离子含量不能准确测定的问题,本文提出了一种利用pH控制沉降铁离子,采用EDTA滴定法准确测定钢铁除锈废酸中的锌离子含量的方法,并通过多项式拟合,得到锌离子含量的拟合曲线的回归方程。研究分析了Fe^(3+)、Fe^(2+)对测量结果的影响,提出了解决方法,同时发现加入聚丙烯酰胺(PAM)做絮凝剂可加快Fe^(3+)的沉降。本方法可为此类废酸的综合利用提供检测依据。

蓖麻油酸锌中锌含量测定方法的研究

如今,蓖麻油酸锌作为一种高效环保的新型除臭材料而被广泛应用,其中锌含量的高低会直接影响蓖麻油酸锌的除臭效果。然而,蓖麻油酸锌中锌含量的测定还没有国家标准,相关的文献报道以及实验研究也较少。为此,开展铬黑T指示剂EDTA络合滴定法、二甲酚橙指示剂EDTA络合滴定法以及火焰原子吸收光谱法测定蓖麻油酸锌中锌含量的对比研究实验,并分析EDTA络合滴定法测定蓖麻油酸锌中锌含量的关键影响因素。研究结果表明,两种EDTA络合滴定法与火焰原子吸收光谱法的测定结果较为相近,方法的准确度及适用性都较好,但火焰原子吸收光谱法不适用于大规模生产样品的分析,两种EDTA络合滴定法操作简便快捷且经济,更能满足实际检测需求。

小麦富锌育种的发展现状及研究趋势

本文总结分析了农田土壤锌含量分布现状、锌对小麦籽粒营养品质的影响、小麦对锌的吸收积累特性以及小麦籽粒锌营养强化途径等。土壤中锌含量的分布特征与地形地貌、地质构造和生态环境等密切相关,部分小麦主产区的土壤中锌含量较低。锌是一种重要的微量元素,对小麦籽粒淀粉和蛋白质含量均有影响,一般被植物根系吸收后,在根部压力或蒸腾作用下被输送到地上部,或者被横向输送到韧皮部,由韧皮部进行向上或向下的运输,再被运输到各组织和器官中。小麦锌强化途径包括遗传改良育种、农艺改良和生物技术应用等。研究结果为小麦富锌育种提供了一些新的思路。

汉中市土壤有效锌的含量分布及影响因素分析

针对汉中市农业生产中存在施肥措施不当,致使部分地方土壤微量元素养分供给能力失衡,限制了水稻、玉米等粮食作物产量的提升等问题。本研究在汉中市11个县区共采集土壤样品6142个,采用DTPA浸提-原子吸收分光光度计测定法统计分析了土壤有效锌的含量和分布。结果表明:汉中市土壤有效锌含量主要分布在0.51~1.0 mg/kg和1.01~1.5 mg/kg这2个区间,占总量的34.80%和30.80%,而有效锌含量低于1.5 mg/kg的土壤样品占总量的78.3%,即汉中市78.3%的土壤有效锌含量处于中等水平以下,47.4%的土壤有效锌含量处于低和很低的水平。水稻、玉米产区土壤有效锌平均含量为1.11 mg/kg,其中水稻耕作区为1.15 mg/kg,玉米耕作区为1.07 mg/kg。水稻耕作区土壤有效锌含量高于玉米耕作区,略高于平均值。土壤中有效锌含量与土壤pH、土壤有机质含量及土壤有效磷含量都呈现负相关。综上所述,汉中市耕作土壤有效锌总体能够满足作物生长的需求,但在部分缺锌地区,建议加强锌肥、有机肥的施用,减少土壤缺锌对作物的影响。

原子吸收火焰法测定消朦片中葡萄糖酸锌含量

目的建立测定消朦片中葡萄糖酸锌含量的原子吸收火焰法。方法测定波长为213.9 nm,狭缝宽度为0.2 nm,锌灯空心阴极灯电流为5.0 mA,氘灯背景校正。结果葡萄糖酸锌质量浓度在2.784~13.920 mg/L范围内与吸光度线性关系良好(r=0.9997,n=5);精密度、稳定性、重复性试验结果的RSD均不超过1.0%;平均加样回收率为100.22%,RSD为1.29%(n=9);含量测定中,该法检测结果的RSD明显优于标准中的紫外分光光度法。结论该方法操作简便,重复性好,精密度高,结果准确,可用于消朦片的质量控制。

探讨ICP-AES法在测定多金属矿石银铅锌含量中的应用

多金属矿石是工业和技术发展的重要资源,其中铜、铅、锌的含量对于矿石的价值和加工过程具有重要影响。传统的元素分析方法往往费时、复杂,难以应对复杂矿石样品的分析需求。感应耦合等离子体原子发射光谱法(ICP-AES)以其高灵敏度、快速响应和准确度高的特点,为多元素同时分析提供了有效手段。本文旨在探究ICP-AES在多金属矿石中铜、铅、锌含量测定中的应用效果,通过优化样品处理方法和分析流程,旨在提高分析的准确性和可靠性。

高分散性活性剂SA-800在胎面胶中的应用

研究高分散性活性剂SA-800(简称SA-800)等氧化锌含量(简称等锌)或减氧化锌含量(简称减锌)替代普通氧化锌在胎面胶中的应用。结果表明:SA-800等锌替代普通氧化锌时,胎面胶的焦烧时间和正硫化时间延长,加工安全性好,其他性能基本相当,可在丁苯橡胶/顺丁橡胶/白炭黑胎面胶和天然橡胶/炭黑胎面胶中替代普通氧化锌;SA-800减锌替代普通氧化锌时,胎面胶的焦烧时间和正硫化时间与等锌替代时相比略有缩短,仍长于普通氧化锌胎面胶,其他性能变化不大,且与普通氧化锌胎面胶基本相当。使用SA-800可实现锌减量的目的。

低锌高炉灰选锌与铁炭分离可行性研究

为提高唐山某低锌高炉灰的综合利用率,达到入窑锌粉锌品位6%左右的要求,进行了旋流器分级分选+螺旋分选机分选试验。试验结果表明:①锌品位1.75%的高炉灰经1粗1精两段旋流器分级分选,最终可获得锌品位分别为5.96%、6.27%,锌回收率分别为47.10%和44.21%的锌粉。②对产率15%左右的二段旋流器底流采用螺旋分选机分离铁、炭,螺旋分选机内圈产品铁品位分别为47.76%、48.98%,可作为低品位铁产品,或并入底流1一并开展后续选铁试验;螺旋分选机中圈和外圈产品铁品位在34%左右,热量值在2500 cal/kg左右,铁品位和热量均不高,且粒度较细,处理难度大,没有再处理或作为单独产品的意义。研究确定了较理想的锌回收工艺,可作为开发利用依据。

基于ICP-AES的岩石中锌元素含量分析与特征研究

锌作为地壳中常见的元素之一,其在地球科学中的分布和行为长期以来一直是研究的焦点。锌的地球化学特性使其在多种地质过程中扮演重要角色,同时也是许多生态系统和工业应用中的关键元素。随着分析技术的发展,ICP-AES已成为分析岩石中微量元素含量的主要方法之一。该技术以其高灵敏度、准确性和多元素分析能力,为研究岩石中锌元素含量提供了强有力的工具。本文利用ICP-AES技术系统地分析了不同类型岩石中的锌元素含量,并探讨其地质意义。