Corrosion resistance of cerium-doped zinc calcium phosphate chemical conversion coatings on AZ31 magnesium alloy

Zinc calcium phosphate （Zn-Ca-P） coating and cerium-doped zinc calcium phosphate （Zn-Ca-Ce-P） coating were prepared on AZ31 magnesium alloy. The chemical compositions, morphologies and corrosion resistance of coatings were investigated through energy-dispersive X-ray spectroscopy （EDS）, X-ray photoelectron spectroscopy （XPS）, X-ray diffraction （XRD）, electron probe micro-analysis （EPMA） and scanning electron microscopy （SEM） together with hydrogen volumetric and electrochemical tests. The results indicate that both coatings predominately contain crystalline hopeite （Zn3（PO4）2·4H2O）, Mg3（PO4）2 and Ca3（PO4）2, and traces of non-crystalline MgF2 and CaF2. The Zn-Ca-Ce-P coating is more compact than the Zn-Ca-P coating due to the formation of CePO4, and displays better corrosion resistance than the Zn-Ca-P coating. Both coatings protect the AZ31 Mg substrate only during an initial immersion period. The micro-galvanic corrosion between the coatings and their substrates leads to an increase of hydrogen evolution rate （HER） with extending the immersion time. The addition of Ce promotes the homogenous distribution of Ca and formation of hopeite. The Zn-Ca-Ce-P coating has the potential for the primer coating on magnesium alloys.

Spectral Properties and Sensitization of Ce^(3+) and Eu^(2+) Codoped Calcium Zinc Chlorosilicate

The Ce^3+ and Eu^2+ ions codoped calcium zinc chlorosilicate Ca_8Zn(SiO_4)_4Cl_2 phosphors have been synthesized for the first time. The diffuse reflection, excitation and emission spectra of Ca_8Zn(SiO_4)_4Cl_2∶Ce^3+, Eu^2+ have been measured at room temperature. The luminescence sensitizaiton of Eu^2+ by Ce^3+ inCa_8Zn(SiO_4)_4Cl_2∶Ce^3+, Eu^2+ has been expounded under the excitation of ultraviolet light and the efficient nonradiative energy transfer from Ce^3+ to Eu^2+ in this system is confirmed.

Leaching of lead from zinc leach residue in acidic calcium chloride aqueous solution

A process with potentially reduced environmental impacts and occupational hazards of lead-bearing zinc plant residue was studied to achieve a higher recovery of lead via a cost-effective and environmentally friendly process. This paper describes an optimization study on the leaching of lead from zinc leach residue using acidic calcium chloride aqueous solution. Six main process conditions, i.e., the solution pH value, stirring rate, concentration of CaC12 aqueous solution, liquid-to-solid （L/S） ratio, leaching temperature, and leaching time, were inves- tigated. The microstructure and components of the residue and tailing were characterized using scanning electron microscopy （SEM） and X-ray diffraction （XRD）. On the basis of experimental results, the optimum reaction conditions were determined to be a solution pH value of 1, a stirring rate of 500 r·min-1, a CaC12 aqueous solution concentration of 400 g·L-1, a liquid-to-solid mass ratio of 7：1, a leaching tempera- ture of 80℃, and a leaching time of 45 min. The leaching rate of lead under these conditions reached 93.79%, with an iron dissolution rate of 19.28%. Silica did not take part in the chemical reaction during the leaching process and was accumulated in the residue.

Effects of Copper-Zinc Alloy Doped with Rare Earth Elements on Crystal of Calcium Carbonate

A copper-zinc alloy doped with rare earth elements was prepared and the mechanism was demonstrated in a simulating boiler and circulating cooling water with rigidity 1 mmol·L-1. The polar curve and scale inhibiting ability of the alloy was tested by a corrosion measurement system and a scale inhibition evaluation system, respectively. Scale samples were characterized with SEM and XRD. It is found that the transfer of cations could be promoted by doping with proper rare earth elements, and the corrosion potentials descend by 25～126 mV. The results indicated that the copper-zinc alloy doped with rare earth elements has higher scale inhibiting ability of CaCO3. The growth of calcite was affected by zinc ions dissolved because of primary battery reaction, and the transition of calcium carbonate from aragonite to calcite was hampered resulting in the proportion of aragonite to calcite is changed from 1.7∶1 to 2.7∶1.

Effect of "Jia Wei Fo Shou San" on Erythrocyte Membrane Calcium,Zinc Concentration in Pregnant Rats with Asymmetrical Intrauterine Growth Retardation Induced by Passive Smoking

Using experimental model of pregnant rats with asymmetrical intrauterine fetal growth retardation induced by passive smoking, the effects of natural herb 'Jia Wei Fo Shou San' on erythrocyte membrane calcium, zinc concentration were observed by atomic absorption spectrophotometry. The results showed that the mean fetal birth weight, zinc concentration of erythrocyte membrane were found to be decreased in the model group as compared with the control group (P＜0. 01, P＜0. 01). On the other hand, the element of calcium onto erythrocyte membrane were higher in model group than that in control group(P＜0. 05). These changes were significantly mild in the treated group and were similar to those of the control group (P＜0.05). Furthermore,our findings indicated that the zinc concentration of erythrocyte membrane seems to be positively correlated with the birth weight(P＜0. 01). Calcium composition of red cell membrane showed a significant negative relation to the birth weight (P＜0.05). Our results provided an experimental evidence that normal concentrations of calcium and zinc onto erythrocyte play an important part in fetal growth. One of the mechanisms of 'Jia Wei Fo Shou San' in improving fetal growth may have something to do with modulation of erythrocyte calcium,zinc element,thereby protecting bio-functions of erythrocyte and promoting blood circulation.

Effects of pH value of reaction solution on structure and electrochemical performance of calcium-containing active material of secondary zinc electrodes

The calcium-containing active material of secondary alkaline zinc electrodes was prepared by a chemical coprecipitation method and characterized by scanning electron microscopy(SEM) and X-ray diffractometry(XRD). Their electrochemical performance was tested by the Galvanstatic charge-discharge method. The experimental results show that the sample synthesized at pH=11.15 has a typical calcium zincate crystal. The zinc electrode using this sample as active material shows higher discharge capacity, more negative discharge plateau potential and longer cycle lifetime.

THE EFFECT OF STATUS OF ZINC, CALCIUM ON GROWTH OF CHILDREN AGED 3～6 YEARS IN XI'AN AND ANALYSIS OF EFFECTIVENESS OF ZINC SUPPLEMEINT

In this study the correlation of heights and weights of 456 healthy children in xi'an aged 3 to 6 years with concentrations of serum zinc, calcium was investigated. The results showed that the concentrations of serum zinc and calcium in the three groups with heights (weights) <x, <x - sand < x - 2s were significantly lower than those in the group with heights (weights) ≥x (P <0. 01). Heights- weights and level of serum calcium of 156 zinc deficient children were lower than those of the children with normal zinc. After zinc supplement, heights and weights of children rapidly increased (P < 0. 01) and calcium level significantly rose (P < 0. 01), with the increase in serum zinc- It is suggested that the deficiency of Zn in children in Xi'an is considerably common and the preschool children with poor growth should be supplemented by zinc

THE STUDY ON THE CHANGES OF ZINC, COPPER, CALCIUM AND MAGNESIUM IN PLASMA AND ERYTHROCYTES DURING CARDIOPULMONARY BYPASS

Objective To study the changes and their influence factors involved of zinc, copper, calcium and magnesium in plasma and erythrocytes during cardiopulmonary bypass(CPB). Methods Zinc, copper, calcium and magnesium values in plasma and erythrocytes were measured by atomic absorption spectrophotometer during CPB. Results Zinc and copper levels in plasma were significantly elevated above preinduction level before perfusion, but calcium and magnesium levels did not change significantly; zinc, copper and calcium levels in plasma were significantly below preoperation level during CPB, but magnesium level in plasma was significantly increased above preoperation; zinc level in plasma was increased to preoperation level after CPB and began to decrease again at 8 hours after CPB, copper level in plasma was increased to preoperation level at 20 hours after CPB, calcium in plasma was increased significantly from beginning to 8 hours after CPB, magnesium level in plasma was decreased to preoperation level at 8 hours afterCPB. Concentration of zinc , copper, calcium and magnesium in erythrocytes did not change significantly. Conclusion During CPB, the changes of zinc, copper, calcium and magnesium had relation to hemodilution, operative wound, carrier protein, stress and component of priming solution and cardioplegic solution, but no relation to transfer from plasma erythrocytes. The results indicate that it is beneficial to patient's recovery to supplement zinc, copper, calcium and magnesium properly by different ways during cardiac perioperation.

Phase Transformation of Amorphous Calcium Carbonate to Single-Crystalline Aragonite with Macroscopic Layered Structure in the Presence of Egg White Protein and Zinc Ion

Highly oriented calcium carbonate lamellas are exquisite structure produced by biomineralization. Strategies mimicking nature have been developed to synthesize inorganic materials with excellent structures and optimal properties. In our strategy, egg white protein and zinc ion were employed in the solution to induce the crystallization of calcium carbonate, resulting in the macroscopic aragonite laminate with an average length of 1.5 mm, which was comprised of single-crystalline tablets. During the crystallization at initial stage, it was found that the particles displayed the characteristics of amorphous calcium carbonate, which was then transformed into the sophisticated structured aragonite through a multistage assembly process. The rebuilt nacre structure in vitro was achieved owing to the synergistic effects of egg white protein and zinc ion.

白云石可控碳化联产氢氧化镁和碳酸钙及其改性

综合利用白云石开发出高端产品及其技术成为当前研究者关注的焦点。本文通过可控碳化法进行白云石联产制备了高附加值的氢氧化镁和碳酸钙并对其进行改性研究。分别考察了碳化终点pH、温度、二氧化碳流速对产物晶型、粒径、形貌的影响以及硬脂酸锌的添加量、搅拌转速、改性时间、改性温度对产物改性效果的影响。结果表明,当碳化反应终点pH控制为10.5时,生成产物为碳酸钙和氢氧化镁混合物,且得率最高;最优的碳化反应条件为温度20℃、二氧化碳流速1L/min,生成的氢氧化镁和碳酸钙平均粒径为190.4nm;得到的产物氢氧化镁和碳酸钙最优的改性条件为硬脂酸锌添加量1.0%、搅拌转速600r/min、改性时间60min、改性温度50℃,得到改性的氢氧化镁及碳酸钙的活化度为95.8%,吸油值为41.2g/100g。

血清25-羟基维生素D、钙、锌水平与儿童生长发育的关系

目的观察儿童血清25-羟基维生素D钙、锌水平,并探析3项指标与儿童生长发育的关系。方法将2021年1月至2022年12月于自贡市妇幼保健院接受治疗的98例生长发育迟缓患儿纳入生长发育迟缓组,另取同期于该院体检的80例生长发育正常的儿童为生长发育正常组,对比2组血清25-羟基维生素D钙、锌水平及其他临床资料,分析血清25-羟基维生素D钙、锌水平与生长发育的关系。结果生长发育迟缓组身长/身高、体重、钙、锌、25-羟基维生素D水平低于生长发育正常组(P<0.05);经点二列相关性分析结果显示,钙、锌、25-羟基维生素D水平与儿童生长发育迟缓呈负相关(r<0,P<0.05);建立Logistic回归模型,结果显示,身长/身高(95%CI:0.673~0.824)、体重(95%CI:0.477~0.717)、钙(95%CI:0.127~0.467)、锌(95%CI:0.140~0.571)、25-羟基维生素D(95%CI:0.130~0.461)水平是儿童生长发育的保护因素(OR<1,P<0.05);绘制ROC曲线,结果显示,钙、锌、25-羟基维生素D水平对儿童生长发育具有一定预测价值(AUC=0.601、0.627、0.667),3项指标并联预测价值更高(AUC=0.808)。结论儿童生长发育状况与血清25-羟基维生素D钙、锌水平密切相关,临床应动态监测血清25-羟基维生素D钙、锌水平变化,有助于早期预测儿童生长发育状况。

薏米多肽-钙、锌螯合物制备及结构表征

目的:制备1种薏米多肽-钙、锌螯合物并研究其结构。方法:利用枯草芽孢杆菌和嗜热链球菌混合发酵薏米,采用葡聚糖凝胶Sephadex G-15、反相高效液相色谱(RP-HPLC)分离纯化薏米发酵液得到薏米多肽(CSP),Tricine-十二烷基硫酸钠-聚丙烯酰胺凝胶(Tricine-SDS-PAGE)电泳检测其分子质量。以锌螯合率和钙螯合率为指标,在单因素实验的基础上,采用响应面试验优化薏米多肽-钙、锌螯合物(CSP-Ca-Zn)的制备工艺,采用紫外光谱、红外光谱和荧光光谱表征其结构。结果:薏米发酵液经Sephadex G-15分离得到4个峰,其中A3的钙、锌螯合率最高。RP-HPLC分离A3得到的CSP纯度达93.91%,其分子质量约7.8 ku。CSP与Ca-Zn螯合的最佳制备工艺为:CSP与钙、锌质量比4.4∶1,钙、锌质量比1∶1,pH 3.7,在此条件下,锌螯合率、钙螯合率分别达到52.63%和63.79%。CSP与钙、锌螯合的主要位点是氨基氮、羧酸基,其空间结构也发生改变。结论:所确定的螯合工艺条件使CSP同时螯合钙、锌两种金属,为薏米多肽新产品的开发提供了技术参考,为制作食源性有机钙、锌补充剂提供了新思路。

葡萄糖酸钙锌口服溶液中5-羟甲基糠醛含量测定方法研究

目的针对葡萄糖酸钙锌口服溶液中5-羟甲基糠醛(5-HMF)检查方法进行研究,建立干扰小、定量准确的测定方法。方法采用高效液相色谱法,C_(18)色谱柱(250 mm×4.6 mm,5μm);以0.05 mol/L磷酸二氢钾溶液(用磷酸调节pH值至3.5)为流动相A,乙腈为流动相B,梯度洗脱,流速1.0 ml/min,检测波长284 nm。结果5-羟甲基糠醛在0.001~2.067μg/ml范围内与峰面积呈良好的线性关系,线性相关系数r为0.9999;检测限为0.207 ng/ml,定量限为0.689 ng/ml;平均回收率为99.4%,RSD范围为0.5%(n=6)。结论本法可用于葡萄糖酸钙锌口服溶液中5-羟甲基糠醛的限量检查,可为该品种质量标准提升提供参考。

利用含锌工业固废制备高纯氧化锌的工艺研究

针对氧化锌尾矿和废弃水渣等工业固废中有价锌难以回收的问题,以当地工业含锌固废为原料,利用碳热还原氧化法,制备了高纯氧化锌微粉。通过HSC Chemistry进行热力学计算和试验研究结合的方式,分析了含锌废渣中硅酸锌与碳还原反应的热力学过程。讨论了配碳量、焙烧温度、焙烧时间以及CaF_(2)对硅酸锌还原过程锌产率的影响。结果表明,在以CaF_(2)为催化剂时,1000~1100℃催化效果最显著。得出最佳工艺条件:在温度为1100℃、保温时间40 min、碳含量20 wt%、CaF_(2)添加5 wt%的条件下锌产率(氧化锌回收率)为97.44%。对挥发产物进行结构和成分分析,其物相为六方纤锌矿结构的氧化锌晶体,粒度大小2~4μm,纯度达到了99.47%。

锌钙系复合磷化膜的制备及其对16Mn钢腐蚀防护性能的影响

通过磷酸盐沉淀结晶过程将聚四氟乙烯(PTFE)颗粒引入锌钙系磷化膜中获得锌钙系复合磷化膜,并研究PTFE颗粒分散液添加量和搅拌速度对锌钙系磷化膜的微观形貌、化学组成、PTFE颗粒含量、厚度以及对16Mn钢的腐蚀防护性能的影响。结果表明:改变PTFE颗粒分散液添加量或搅拌速度制备的不同锌钙系复合磷化膜晶粒大小较均匀,但是呈散乱无序状堆积,PTFE颗粒附着在晶粒表面并填补晶粒间孔洞,起到阻挡腐蚀介质并阻碍腐蚀反应的作用,明显提高锌钙系复合磷化膜的耐腐蚀性能。当搅拌速度为300 r/min时,添加25 mL/L PTFE颗粒分散液制备的锌钙系复合磷化膜晶粒表面附着较多PTFE颗粒,并且颗粒呈较均匀分散状态很好的填补晶粒间孔洞。该复合磷化膜含有Zn、Ca、P、O、C和F元素,PTFE颗粒的含量和厚度分别达到4.1%、12.4μm,具有最高的电荷转移电阻8528Ω·cm^(2)和低频阻抗值6015Ω·cm^(2),表现出优异的耐腐蚀性能,使16Mn钢的腐蚀防护性能明显优于常规锌钙系磷化膜。

环保钙/锌PVC热稳定剂的发展现状及应用

热稳定剂是聚氯乙烯(PVC)加工过程中重要的塑料助剂,可以抑制聚氯乙烯在高温下发生热降解,改善PVC热稳定性能。PVC是全球五大通用塑料之一,国内外对PVC的需求量逐渐增大,热稳定剂的消耗量随之增长,因此,低毒、无污染且高效环保的钙/锌热稳定剂成为研究热点。介绍了近年来国内外聚氯乙烯热稳定剂的发展现状,由于铅、镉盐类热稳定剂有毒,已被欧盟禁用,有机锡类热稳定剂价格昂贵,而环保钙/锌热稳定剂市场需求急剧增加。综述了钙/锌热稳定剂的研究现状,分析了环保热稳定剂对PVC的作用机理,提出了钙/锌热稳定剂市场应用前景和未来的发展重点及方向。

不同钙锌稳定剂搭配不同碳酸钙对管材颜色影响的研究

本文采用不同的钙锌稳定剂搭配不同的碳酸钙,探索其对管材颜色的影响。通过测试不同制品的色度值,得出以下结论:钙锌稳定剂底色是影响制品外观颜色的关键原因,当配方长期热稳定性满足生产需求时,优选底色偏白相的稳定剂,能得到色相较白的产品;碳酸钙底色是影响制品颜色的重要原因,优选底色呈现黄白相的碳酸钙来生产管材。

用于可见光降解甲基橙的ZnIn_(2)S_(4)/CaIn_(2)S_(4)光催化剂性能

采用一步水热法构建了ZnIn_(2)S_(4)/CaIn_(2)S_(4)(ZIS/CIS)异质结光催化剂。通过XRD、SEM、DRS、电化学测试等表征研究此异质结光催化剂的晶体结构、形貌、光学性质及光生载流子的分离效率,在模拟可见光下考察其对甲基橙的降解效率。实验结果表明,ZIS/CIS异质结材料对甲基橙的降解效果明显优于CIS和ZIS。ZIS摩尔分数为30%的复合样品具有最佳的甲基橙降解效率,60 min内达到95.54%,并且具有良好的稳定性。

葡萄糖酸钙锌联合维生素D治疗维生素D缺乏性佝偻病患儿的效果

目的:观察葡萄糖酸钙锌联合维生素D治疗维生素D缺乏性佝偻病患儿的效果。方法:选取2021年4月至2023年3月郑州市金水区总医院收治的72例维生素D缺乏性佝偻病患儿进行前瞻性研究,按照随机数字表法分为观察组与对照组各36例。对照组采用维生素D治疗,观察组在对照组基础上联合葡萄糖酸钙锌治疗,比较两组生长指标{血清骨碱性磷酸酶(BALP)、血清25-羟维生素D3[25-(OH)D3]、身高}水平、骨代谢指标[血清硬骨素(SOST)、抗酒石酸酸性磷酸酶5b(TRAP-5b)、Ⅰ型胶原交联羧基端肽(CTX-Ⅰ)、成纤维细胞生长因子23(FGF23)、粒细胞集落刺激因子(G-CSF)]和不良反应发生率。结果:治疗3、6个月后,观察组身高及25-(OH)D3、SOST、TRAP-5b、CTX-Ⅰ水平高于对照组,BALP、FGF-23、G-CSF水平低于对照组,差异均有统计学意义(P<0.05);两组不良反应发生率比较,差异无统计学意义(P>0.05)。结论:葡萄糖酸钙锌联合维生素D治疗维生素D缺乏性佝偻病患儿可改善其生长指标和骨代谢指标水平,效果优于单纯维生素D治疗。

湿法炼锌污酸处理中石膏渣减量化工艺探索

针对目前湿法炼锌中采用石灰中和法处理污酸产生的石膏渣量较大的问题,本文提出采用锌焙砂-碳酸钙两段中和法处理硫化后液的工艺并进行试验。该工艺通过锌焙砂中和部分酸,再采用碳酸钙进行中和,将氟除去的同时减少污酸石膏渣产量。实验结果表明,采用锌焙砂中和时,控制pH值为2.0~2.5,在温度35℃条件下中和1 h,沉降过滤后采用碳酸钙进行二段中和,控制终点pH为5.0~5.5,反应1 h,沉氟后液含氟量小于20 mg/L,沉氟率超过98%,产出石膏渣仅为传统石灰中和法所产石膏渣量的24.94%,溶液经过除氯后可返回湿法系统中。