Improved continuous precipitation kinetics and tensile properties of extruded AZ80 alloy through {10-12} twin formation

This study investigates the effect of {10-12} deformation twins on the continuous precipitation behavior of an extruded Mg-8.0Al-0.5Zn-0.2Mn(AZ80) alloy during aging. The extruded AZ80 alloy is compressed along the transverse direction to introduce {10-12} twins,followed by an aging treatment at 300 ℃. The extruded material exhibits a twin-free microstructure with low internal strain energy, whereas the pre-twinned material possesses abundant {10-12} twins and has high internal strain energy. The aging results reveal that the peak-aging time of the pre-twinned material(1 h) is one-eighth of that of the extruded material(8 h). Although Mg_(17)Al_(12) continuous precipitates(CPs)are observed in both the peak-aged materials, these CPs are much smaller and more densely distributed in the pre-twinned material despite the significantly shorter aging time. The CPs size in the peak-aged materials increases in the following order: twinned region in the pre-twinned material(0.47 μm) < residual matrix region in the pre-twinned material(1.71 μm) < matrix region in the extruded material(2.55 μm).Moreover, the CPs number density in the twinned region of the pre-twinned material is approximately 11 times higher than that in the matrix region of the extruded material. The peak-aged pre-twinned material exhibits significantly higher tensile strength and ductility than the peak-aged extruded material. These results demonstrate that the formation of {10-12} twins in the extruded AZ80 alloy substantially accelerates the static precipitation of CPs during aging at 300 ℃ and improves the tensile properties of the peak-aged material.

Improvement of 6–15 Day Precipitation Forecasts Using a Time-Lagged Ensemble Method

A time-lagged ensemble method is used to improve 6-15 day precipitation forecasts from the Beijing Climate Center Atmospheric General Circulation Model,version 2.0.1.The approach averages the deterministic predictions of precipitation from the most recent model run and from earlier runs,all at the same forecast valid time.This lagged average forecast （LAF） method assigns equal weight to each ensemble member and produces a forecast by taking the ensemble mean.Our analyses of the Equitable Threat Score,the Hanssen and Kuipers Score,and the frequency bias indicate that the LAF using five members at time-lagged intervals of 6 h improves 6-15 day forecasts of precipitation frequency above 1 mm d-1 and 5 mm d-1 in many regions of China,and is more effective than the LAF method with selection of the time-lagged interval of 12 or 24 h between ensemble members.In particular,significant improvements are seen over regions where the frequencies of rainfall days are higher than about 40％-50％ in the summer season; these regions include northeastern and central to southern China,and the southeastem Tibetan Plateau.

酪蛋白磷酸肽-钙螯合物的分级、表征及持钙特性

利用酪蛋白磷酸肽螯合钙离子的特性,以钙离子浓度为尺度,分级制取不同钙螯合能力的CPPs,同时提高其纯度。以酪蛋白的胰蛋白酶酶解产物为原料,通过逐级增加Ca^(2+)添加量,在终浓度为55%(v/v)的乙醇溶液中分级沉淀出三个酪蛋白磷酸肽-钙螯合物级分(CPP1-Ca、CPP2-Ca和CPP3-Ca),并利用PBS脱钙得到三个级分相应的酪蛋白磷酸肽(CPP1、CPP2和CPP3)。以传统钙乙醇沉淀法得到的肽钙螯合物(CPP-Ca)为对照,分析并对比三个酪蛋白磷酸肽-钙螯合物级分的理化性质以及持钙特性。结果表明,三个酪蛋白磷酸肽-钙螯合物级分中,CPP3-Ca含有最高的纯度和钙螯合量,分别为89.42%和69.59 mg/g,明显高于未分级CPP-Ca的83.77%和55.05 mg/g。氨基酸组成及N/P(摩尔比)分析发现CPP3-Ca含有更高磷酸丝氨酸基团,进而能够结合更多的Ca^(2+)。不同酪蛋白磷酸肽级分持钙能力分析结果显示CPP3能够更好地延迟和阻止磷酸钙沉淀的形成,具有更高的持钙能力。同时CPP3-Ca在模拟肠道环境中具有更高的钙溶解度,表明分级后的酪蛋白磷酸肽-钙螯合物的体外生物利用度提高。

Multi-time Scale Analysis of the Precipitation Series in Chengde City in Recent 58 Years

[ Objective] The research aimed to analyze variation rule of the precipitation series in Chengde City in recent 58 years. [Method] Mexi- can hat wavelet was used to analyze multi-scale characteristics of the monthly precipitation data in Chengde from 1951 to 2008. We revealed multi- time-scale complex structure of the precipitation change in Chengde, analyzed change cycles and mutation points of the precipitation series under different time scales, and identified primary period in each series. [ Result]There were high/low value centers of the precipitation under interdec- adal scale （more than 10 years）. Under interannual scale （below 10 years）, oscillation was complex and variable, but 4-year scale had obvious high-frequency oscillation. Wavelet variance analysis verified existence of the 4-year precipitation cycle, and M - K test also confirmed conclusions of the wavelet analysis. [ Conclusion] We could judge from alternating wet and dry conditions that the wet year decreased significantly, and the cur- rent Drecioitation was still less than normal.

A new synthetic chelating collector for the flotation of oxidized-lead mineral

A new synthetic reagent DPTUHP [diphenyl α-（3-phenylthioureido） hexylpbosphonate] containing a hydrocarbon chain nonpolar group, a thioureido, and a phosphonate easter chelating group, has proven to be an effective collector for the flotation of cerussite mineral. The synthetic method utilized the Mannich-type reaction of an N-monosubstituted thiourea, an aldehyde, and triphenyl phosphate in glacial acetic acid solution. The experimental results of flotation of the cerussite mineral show that the collector has stronger collecting ability and higher selectivity in a neutral and a slightly alkaline medium, especially in the pulp of pH=8. Using the measurements by infrared spectroscopy （IR） and X-ray photoelectron spectroscopy （XPS） of the cerussite mineral, the collector, as well as the cerussite treated with the collector, the flotation mechanism of cerussite has been discussed. It is concluded that the adsorption of collector on cerussite is a chemical adsorption through the electron donor atoms of the collector chelating the Pb （ Ⅱ ） of cerussite to form chelate.

重金属絮凝剂DTAPAM去除水中Cu-EDTA的条件优化和机理

工业含Cu废水中常含有配位剂EDTA,可与Cu(Ⅱ)配位后形成稳定的可溶性配合物Cu-EDTA,致使废水中的Cu(Ⅱ)较难被除去.为了将含Cu-EDTA废水中的Cu(Ⅱ)得以有效去除,采用二硫代羧基化胺甲基聚丙烯酰胺(DTAPAM)作为重金属絮凝剂,以Cu-EDTA为处理对象,研究了絮凝水力条件、DTAPAM投加量、pH值、EDTA浓度、Cu(Ⅱ)初始浓度对DTAPAM去除Cu-EDTA性能的影响,确定了Cu(Ⅱ)的最佳去除条件;并利用紫外-可见吸收光谱、红外光谱、扫描电镜及能谱分析等表征方法探究了DTAPAM去除Cu-EDTA的机理.结果表明,最佳絮凝水力条件为快搅时间2min、快搅速度160r/min、慢搅时间20min、慢搅速度50r/min;当pH值为5.0~7.0时,DTAPAM对Cu(Ⅱ)初始浓度为25mg/L的含Cu-EDTA水样的去除性能均较好,且在pH值为7.0时Cu(Ⅱ)的去除效果最好,最高去除率可达99.07%;当体系中EDTA与Cu(Ⅱ)配位比为1:1时,DTAPAM对不同Cu(Ⅱ)初始浓度的含Cu-EDTA水样均具有理想的去除效果.表征结果显示,DTAPAM高分子链中的二硫代羧基(—CSS-)与水样中Cu(Ⅱ)发生了螯合反应;pH值为2.0~9.0时,DTAPAM-Cu螯合稳定常数的对数值介于13.09~13.71.DTAPAM处理含Cu-EDTA水样时,DTAPAM先与EDTA发生配位竞争作用,将Cu-EDTA中的Cu(Ⅱ)解络出与之发生螯合反应生成絮体沉淀物,絮体间发生以吸附架桥和网捕卷扫为主的絮凝作用,促进絮体的沉降,提高了Cu(Ⅱ)的去除.

Laboratory investigation of a new scale inhibitor for preventing calcium carbonate precipitation in oil reservoirs and production equipment

The formation of mineral scale is a complex problem during the oilfield operations. Scale inhibitors are widely used to prevent salt precipitation within reservoirs, in downhole equipment, and in production facilities. The scale inhibitors not only must have high effectiveness to prevent scale formation, but also have good adsorption- desorption characteristics, which determine the operation duration of the scale inhibitors. This work is focused on the development of a new scale inhibitor for preventing cal- cium carbonate formation in three different synthetic for- mation waters. Scale inhibition efficiency, optical density of the solution, induction time of calcium carbonate for- mation, corrosion activity, and adsorption-desorption ability were investigated for the developed scale inhibitor. The optimum concentration of hydrochloric acid in the inhibitor was determined by surface tension measurement on the boundary layer between oil and the aqueous scale inhibitor solution. The results show that the optimum mass percentage of 5 % hydrochloric acid solution in the inhi- bitor was in the range of 8 % to 10 %. The new scale inhibitor had high efficiency at a concentration of 30 mg/L. The results indicate that the induction period for calcium carbonate nucleation in the presence of the new inhibitor was about 3.5 times longer than the value in the absence of the inhibitors. During the desorption process at reservoir conditions, the number of pore volumes injected into the carbonate core for the developed inhibitor was significantly greater than the volume of a tested industrial inhibitor, showing better adsorption/desorption capacity.

CaCl_2螯合沉淀-Fenton氧化联合处理HEDP镀铜废水

采用CaCl2螯合沉淀-Fenton氧化联合处理湖南湘潭某机械厂1-羟基乙叉-1,1-二膦酸(HEDP)镀铜废水,研究了螯合剂CaCl2投加量、反应pH、反应时间,Fenton反应pH、反应时间、H2O2用量、[Fe2+]/[H2O2]比值等对处理效果的影响。结果表明,CaCl2螯合沉淀-Fenton氧化联合方法能有效处理HEDP镀铜废水,在优化反应条件下,COD、TP和Cu2+去除率分别达到95.8%、99.8%和99.87%,出水基本达到电镀污染物排放标准(GB21900-2008)要求。

氧化-螯合沉淀法处理碱性锌镍合金电镀废水

在pH=8~13的条件下,用双氧水破坏碱性锌镍合金电镀废水中的羟基羧酸类配位剂。接着调节废水的pH至4.5~5.5,令脂肪族多胺类配位剂的配位能力降低。然后加焦亚硫酸钠还原废水中残留的双氧水,再以二甲基二硫代氨基甲酸钠螯合沉淀锌和镍离子。当电镀废水中脂肪族多胺的质量浓度不高于于2.5 g/L时,锌和镍的出水浓度满足GB 21900–2008《电镀污染物排放标准》的"表2"要求;当脂肪族多胺低于0.5 g/L时,锌和镍的出水浓度满足GB 21900–2008的"表3"要求。

某电镀园区络合态锌镍废水处理工艺改造

[目的]电镀废水中的锌离子和镍离子一般以稳定的络合态形式存在,处理难度大。某电镀园区络合态废水的原处理工艺为一级氧化破络沉淀+二级螯合沉淀,处理后出水的镍、锌不能稳定达标。[方法]将该园区的废水处理工艺改为一级脱氮破络沉淀+二级螯合沉淀。[结果]改造后,出水的总镍和总锌均能稳定满足GB 21900-2008标准中“表3”的要求,同时吨水运行成本相比于改造前降低了约30元,一年可为园区节约72万元,实现了降本增效的目的。[结论]改造工艺运行稳定,处理效果佳,具有良好的环境效益和经济效益。

Mn-SOD的纯化方法研究

以嗜热芽孢杆菌B．S110-2所产Mn-SOD为研究对象,对其纯化方法进行了研究,用碱处理的方法替代了 传统的硫酸铵分级沉淀蛋白的方法;通过对金属螯合层析中二价金属离子的选择及洗脱液pH的选择,初步建立了一套 适合分离纯化Mn-SOD的金属螯合层析体系,为实际生物产品的分离奠定了基础。

Relationship of microstructure transformation and hardening behavior of type 17-4 PH stainless steel

The relationship between the microstructure transformation of type 17-4 PH stainless steel and the aging hardening behavior was investigated. The results showed that, when 17-4 PH stainless steel aging at 595℃, the bulk hardness of samples attains its peak value （42.5 HRC） for about 20 min, and then decreases at all time. TEM revealed the microstructure corresponding with peak hardness is that the fine spheroid-shape copper with the fcc crystal structure and the fiber-shape secondary carbide M23C6 precipitated from the lath martensite matrix. Both precipitations of copper and M23C6 are the reasons for strengthening of the alloy at this temperature. With the extension of holding time at this temperature, the copper and secondary carbide grow and lose the coherent relationship with the matrix, so the bulk hardness of samples decreases.

重金属捕捉剂DTC-3去除化学镍实验研究

选用三乙烯四胺为原料制备重金属捕捉剂DTC-3,处理深圳某电镀企业废水中的化学镍,研究了DTC-3投加量、pH值、反应时间以及絮凝剂FeSO_(4)投加量等因素对Ni^(2+)去除效果的影响。实验结果表明:在pH值调到9,DTC-3投加量为100 mg/L,搅拌反应15 min,FeSO_(4)投加量为80 mg/L时,残留Ni^(2+)浓度从3.86 mg/L降到0.43 mg/L,去除率高达88.86%,达到电镀污染物排放标准(GB 21900-2008)中表2要求,同时,经对比,除化学镍效果优于某市售重捕剂CL-30,可见DTC-3具有较好的应用前景。

通过螯合镍提高从Zn-Ni硫酸盐溶液中水解沉淀锌的选择性（英文）

研究锌/镍摩尔比为20:1的锌-镍硫酸盐溶液中锌的选择性沉淀过程。将0.5 mol/L NaOH溶液滴加到含0、0.01、0.02、0.03和0.04mol/L乙二胺四乙酸盐(EDTA)作为螯合剂的锌-镍硫酸盐溶液中。利用Visual MINTEQ软件进行沉淀途径的平衡分析。平衡分析结果表明,少量EDTA的存在可以防止镍在碱性条件下沉淀,而对锌的沉淀没有任何不利影响。鉴于此,溶液中仅存在0.03 mol/L EDTA、pH=9.0时,锌的沉淀率超过90%,沉淀产物中Zn含量约为50%,而Ni含量仅为0.11%。为了更完全地分离锌和镍,沉淀后继续搅拌120min。沉淀产物的X射线衍射分析表明,沉淀相为Zn_4(OH)_6SO_4·4H_2O。

中和沉淀-树脂吸附法回收高铁低铜废水中的铜

采用中和沉淀-树脂吸附法回收处理高铁低铜废水中的铜资源,考察了pH值、不同工艺优化对铜铁分离的影响,树脂选型、解析剂浓度、吸附流速等对树脂吸附解析的影响。结果表明:在中和沉淀优化的最佳条件下铁去除率为99.94%,铜损失率为21.11%,采用CN27螯合树脂、解析剂为8wt%硫酸、吸附解析流速为3BV/h条件下,树脂最大吸附时间为9d,Cu^2+最大吸附量23.47mg/mL,以出水Cu^2+浓度0.5mg/L为穿透点,穿透吸附时间为4d,Cu^2+穿透吸附量15.10mg/mL。树脂解析总时长为160min,总解析率达到99.72%。铜资源综合回收率为78.42%。

Direct Synthesis of Al_2O_3-modified Li(Ni_(0.5)Co_(0.2)Mn_(0.3))O_2 Cathode Materials for Lithium Ion Batteries

To improve the cyclic stability at high temperature and thermal stability, the spherical Al2O3-modified Li（Ni0.5Co0.2Mn0.3）O2 was synthesized by a modified co-precipitation method, and the physical and electrochemical properties were studied. The TEM images showed that Li（Ni0.5Co0.2Mn0.3）O2 was modified successfully with nano-Al2O3. The discharge capacity retention of Al2O3-modified Li（Ni0.5Co0.2Mn0.3）O2 maintained about 99% after 200 cycles at high temperature（55 ℃）, while that of the bare one was only 86%. Also, unlike bare Li（Ni0.5Co0.2Mn0.3）O2, the Al2O3-modified material cathode exhibited good thermal stability.

Synthesis of Agomelatine by One-pot Catalytic Hydrogenation and Acetylation with NiO

Nano-NiO and bulk NiO were prepared from Ni(AC)_2·4 H_2O by coordination precipitation using aqueous ammonia and by a solid state reaction, respectively. The nickel oxide particles were characterized by X-ray Diffraction(XRD) and scanning electron microscopy(SEM). The results indicate that nano-sized NiO has a crystal phase with a standard face-centered cubic lattice structure, with a mean particle diameter of about 10 nm. The evaluation of the activity of nickel oxide nanoparticles in the catalytic hydrogenation of 7-methoxy-1-naphthylacetonitrile was carried out. The results demonstrate the efficient synthesis of the title compound by a one-pot catalytic hydrogenation and acetylation with NiO. The NiO nanoparticles displayed superior catalytic activity in the synthesis of agomelatine in the one-pot reaction.The total yield of agomelatine is over 81.8% with a purity of 99.2%, as determined by HPLC. The structure of agomelatine was confirmed by IR, MS, and 1 H NMR analysis.

螯合沉淀法去除稀土冶炼废水中的重金属试验研究

研究了采用螯合沉淀法从稀土冶炼废水中去除铅、锌、镉等重金属,筛选了重金属螯合剂,并通过单因素和正交试验确定了影响重金属去除的主要因素及最佳工艺条件。结果表明:以二甲基二硫代氨基甲酸钠(福美钠)为螯合剂能有效去除稀土冶炼废水中的总铅、总锌、总镉;螯合剂用量对重金属去除率的影响最大,搅拌速度次之,反应时间、废水pH的影响较小;在废水pH=9.5、反应时间15 min、福美钠加入量30 mg/L、搅拌速度180 r/min条件下,经螯合沉淀处理的出水中ρ(∑Pb)<0.2 mg/L、ρ(∑Zn)<1.0 mg/L、ρ(∑Cd)<0.05 mg/L,符合排放标准要求。

Removal of Ni(Ⅱ) from strongly acidic wastewater by chelating precipitation and recovery of NiO from the precipitates

Strongly acidic wastewater produced in nonferrous metal smelting industries often contains high concentrations of Ni(Ⅱ), which is a valuable metal. In this study, the precipitation of Ni(Ⅱ) from strongly acidic wastewater using sodium dimethyldithiocarbamate(DDTC) as the precipitant was evaluated. The effects of various factors on precipitation were investigated, and the precipitation mechanism was also identified. Finally, the nickel in the precipitates was recovered following a pyrometallurgical method. The results show that, under optimised conditions(DDTC:Ni(Ⅱ) molar ratio = 4:1;temperature = 25 ℃), the Ni(Ⅱ) removal efficiency reached 99.3% after 10 min. In strongly acidic wastewater, the dithiocarbamate group of DDTC can react with Ni(Ⅱ) to form DDTC –Ni precipitates. Further recovery experiments revealed that high-purity Ni O can be obtained by the calcination of DDTC –Ni precipitates, with the nickel recovery efficiency reaching 98.2%. The gas released during the calcination process was composed of NO_(2), CS_(2), H_(2)O, CO_(2), and SO_(2). These results provide a basis for an effective Ni(Ⅱ) recovery method from strongly acidic wastewater.

螯合沉淀法处理电路板碱氨蚀刻废水

研究了环境友好型的有机硫螯合剂TMT处理电路板碱氨蚀刻废水的影响因素,用元素分析、红外与X衍射等手段表征了生成的沉淀产物,并对它的热分解性与在去离子水中的渗滤性作了初步探讨。结果表明,TMT能与铜离子强力螯合并沉淀,处理电路板碱氨蚀刻废水的效果好,废水的pH值为8,总铜的质量浓度为350.9mg/L,总氨质量浓度为349.4 mg/L,当TMT与Cu的量比为2.1:3时,上清液中残余铜的质量浓度为0.10 mg/L,铜去除率达99.97%。生成的沉淀物为非晶态的Cu3(C3N3S3)2.1.5H2O,它的热稳定性较高,在去离子水中渗滤出的饱和铜浓度很低,不会对环境造成二次污染。