Development of a new method for analyzing free aluminum ions(Al^(3+)) in seafood using HPLC-ICP-MS

This paper presents a novel method for simultaneous online examination of free aluminum ions(Al3+)in seafood,using solidphase extraction and high-performance liquid chromatography online with inductively coupled plasma mass spectrometry(SPEHPLC-ICP-MS),without post-column reaction.The optimum conditions for chromatographic separation of Al3+were achieved using an IonPac CS5A analytical column with an IonPac CG5A guard column.The mobile phase consisted of 0.040 mol/L LiOH,0.0060 mol/L 2,6-pyridinedicarboxylic acid,and 0.090 mol/L CH3COOH(pH 4.7).The free Al3+ions in seafood were extracted by shaking with the mobile phase at 70°C for 2 h.SPE was conducted using an Oasis MCX,3cc/60 mg,30μm column,which was activated and equilibrated with 2 mL of methanol and 4 mL of deionized water before use.HCl(0.075 mol/L,2 mL)was used to wash inorganic Al from the SPE column.The standard recoveries of Al3+were all above 89%and the relative standard deviations were all below 5%.The proposed method was successfully used for the examination of Al3+in seafood samples,and the results were similar to those obtained using the static equilibrium method.

Process for improving the ladle free- opening rate for high aluminum steel in continuous casting

Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1.6% to 2.45% ,which is significantly higher than other types of steel. According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company, previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are：sand material, accessories baking, ladle nozzle cleaning, the process and amount of adding sand, and the rate of argon stirring during refining. Therefore, improving the ladle filler sand quality, baking all of the raw materials, controlling the addition of ladle filler sand, cleaning the ladle nozzle, and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel.

Forms of free aluminum in soils

The study on the forms and transformations of aluminum in soils has received great at-tention at home and abroad with recognized significanee of the exploitation and utilizationof acidic soils and of the acidification of soils and the associated environmnts caused byacidic deposition. Free iron and aluminum oxides are the most important clay oxides insoils. The study on their forms, transformations and funtions appears to be the front andfocus in the microscopic field of soil science. The research into iron oxides started

Solvent-free preparation of arylaminotetrazole derivatives using aluminum(Ⅲ) hydrogensulfate as an effective catalyst

An efficient and simple method for the preparation of 5-arylamino-1H-tetrazole and 1-aryl-5-amino-1H-tetrazole derivatives is reported using aluminum（Ⅲ） hydrogensulfate（Al（HSO4）3） as an effective heterogeneous catalyst from secondary arylcyanamides. Generally,when the substitution in arylcyanamide is strongly electron-withdrawing the position of equilibrium would shift toward the isomer of 1-aryl-5-amino-1H-tetrazole（B） and as the electron-donating of substituent increased,the position of equilibrium is shifted toward the isomer of 5-arylamino-1H-tetrazole（A）.The present methodology offers several advantages,such as excellent yields,short reaction times,easy work-up and greener conditions.

Deformation behavior of A6063 tube with initial thickness deviation in free hydraulic bulging

Experiment on seamless tubes of aluminum alloy A6063 with initial thickness deviation of 0-20% was conducted through a free hydraulic bulging with tube ends free. The influence of initial thickness deviation on the cross-section profile, thickness distribution, maximum internal pressure and maximum radial expansion was investigated. FEM simulation was also performed in order to examine and help explaining the experimental results. The results indicate that the internal pressure and maximum internal pressure appear to be little influenced by the initial thickness deviation, and that the cross-section profile of the bulged tube changes diversely and can not be a perfect circle. The results also suggest that the increase in initial thickness deviation may lead to a remarkable decrease in maximum radial expansion, and a rapid increase in thickness deviation and the center eccentricity of the inner and outer profiles.

A Study of Structure, Thermal and Mechanical Properties of Free Machining Al-Zn-Sn-Bi Alloys Rapidly Solidified from Molten State

The objective of our study is to investigate the effect of rapid solidification technology using melt spun process from melt on environmentally free machining Al-0.1Zn alloys with tin-bismuth as free machining constituents. The main purpose of rapid solidification from melt is to have a high strength and thermal stability. Structural and thermal properties have been investigated by x-ray diffraction (XRD), scanning electron microscope (SEM) and differential scanning calorimetry (DSC) techniques. Tensile test machine is used to study the mechanical properties such as ultimate tensile strength, elastic constants, yield strength and critical shear stress for free machining alloys. We find?the best free machining aluminum alloy that has excellent machinability qualities is Al-0.1Zn-0.5Sn-0.54Bi melt spun alloy because it offers excellent mechanical properties. The highest values of tensile strength (431.5 MPa), yield strength (393.9 MPa), fracture strength (431.6 Mpa), toughness (15.8 × 106?J/m3) generated from Al-0.1Zn-0.5Sn-0.54Bi alloy to meet the needs of free machining aluminum alloy applications.

Effect of step-quenching on microstructure of aluminum alloy 7055

The effect of step-quenching on the microstructure of aluminum alloy 7055 after artificial aging was studied by hardness testing and transmission electron microscopy (TEM). Step-quenching leads to decomposition of solid solution and heterogeneous precipitation of equilibrium phase mainly on dispersoids and at grain boundaries; thus lower hardness after aging. Prolonging isothermal holding at 415 ℃ results in coarser and more spaced η phase particles at grain boundaries with wider precipitates free zone, and lower density of larger η′ hardening precipitates inside grains after aging. Isothermal holding at 355 ℃ results in heterogeneous precipitation of η phase both on dispersoids and at grain boundaries. Isothermal holding at 235 ℃ results in heterogeneous precipitation of η phase first, and then S phase. Precipitates free zones are created around these coarse η and S phase particles after aging. Prolonging isothermal holding at these two temperatures leads to fewer η′ hardening precipitates inside grains, larger and more spaced η phase particles at grain boundaries and wider grain boundary precipitates free zone after aging.

基于Label-free技术的高州油茶铝胁迫蛋白质组学研究

【目的】南方地区拥有大面积的酸性红壤,导致土壤中铝元素多以离子的形式溶出,严重抑制油茶的生长及高产。研究采用Label-free技术探究高州油茶在铝胁迫下的蛋白质组学响应,为揭示高州油茶应答铝胁迫的分子响应机制奠定了理论基础。【方法】以高州油茶两年生实生苗为试验材料,测定不同浓度铝处理条件下高州油茶叶片部分代谢指标及抗氧化生理相关指标,同时比较对照组(CK)和4 mmol/L铝处理组(GZ4)差异蛋白质的表达。【结果】生理试验结果表明,不同浓度铝胁迫下油茶幼苗都会发生氧化胁迫导致细胞活性氧(ROS)积累,2 mmol/L铝浓度下油茶叶片通过增加渗透调节物质含量和增强多种抗氧化酶活性以清除细胞活性氧,使细胞免受氧化胁迫的损害;而4 mmol/L铝浓度下叶片丙二醛(MDA)含量和脯氨酸(PRO)含量明显升高,积累的活性氧超出了自身所能清除的范围,叶片可溶性糖含量和可溶性蛋白含量显著减少,抗氧化酶活性均有不同程度减弱,油茶正常的生理功能受到抑制。蛋白质组学数据表明,CK组和GZ4组共鉴定到4282个蛋白质,与CK组相比,GZ4处理组有207个蛋白质的表达丰度显著增加,129个蛋白质的表达丰度显著降低。差异表达蛋白质的通路富集和蛋白质互作网络分析结果表明,4 mmol/L铝胁迫下高州油茶主要通过提高谷胱甘肽代谢,增强细胞清除活性氧和自由基负离子的能力缓解铝胁迫造成的氧化损伤;4 mmol/L铝浓度下高州油茶蛋白质合成和光合作用受到明显抑制,抗氧化酶活性减弱可能与细胞供能能力不足有关。【结论】铝胁迫下高州油茶主要通过能量及碳水化合物代谢、氨基酸合成及代谢、生物碱合成、蛋白质加工、卟啉和叶绿素代谢等代谢途径抵抗铝毒。

硫酸铝型无氟无碱液体速凝剂的制备

以硫酸铝和二乙醇胺为主要原料,将乙二醇、三乙醇胺作为辅料进行性能调节,通过优化各组分的用量,制备了一种新型无氟无碱液体速凝剂。使用基准水泥,对速凝剂的凝结时间和1d抗压强度进行了测定。结果显示,速凝剂掺量为7%时,4’12’’时达到初凝,9’23’’时达到终凝;1d的抗折强度和抗压强度分别为3.22MPa和12.39MPa。同时,该液体速凝剂对几种工程水泥也表现出了良好的适应性。

铝合金细化剂细化行为研究现状与展望

晶粒细化处理能够显著改善铝合金的综合性能,对拓展其应用领域意义重大。本文基于异质形核,探讨了点阵错配模型、边边匹配模型以及自由生长模型,肯定了边边匹配模型在筛选潜在晶粒细化剂方面的高效性;根据自由生长模型关于异质相尺寸、形态、分布等对晶粒细化效果影响的理论研究,归纳了物理、化学方法调控第二相进而优化细化效果的研究进展,并且对第二相尺寸影响细化效果的原因进行了理论阐述,最后对优化晶粒细化剂的方向做了展望。

制坯方法对大型铝合金锻件变形均匀性的影响规律

目的解决大型铝合金自由锻拔长制坯组织均匀性差、部分区域力学性能不达标的问题。方法提出了用于对称拔长方法的斜面型拔长砧,该砧两侧均设计为带有一定角度的斜面结构,使拔长进给过程中交界区域形成变形过渡区,在拔长时实现交界区变形的连续性。通过有限元模拟,将该方法与传统非对称拔长以及进给量和压下量组合成不同工艺方案进行比较研究,获得了不同方案拔长对锻坯变形均匀性的影响规律。结果在传统非对称拔长方法下,减小进给量和压下量后,在一定程度上可以提高变形的均匀性,锻坯的等效应变均方差由0.710降为0.633,纵向应变均方差由0.180降为0.162;采用近“V”型斜面拔长砧对称拔长法后,锻坯的等效应变均方差进一步下降为0.605,纵向应变均方差下降为0.098。结论经生产试制可知,采用斜面拔长砧对称拔长法可以大幅度提高拔长坯料的变形均匀性,且纵向的提升效果更为显著。

6063铝合金中性无铬转化膜制备及膜层性能分析

目的提高铝合金微小器件的耐蚀性,开发一种条件温和可控的转化膜成膜工艺。方法采用中性无铬转化工艺,在6063铝合金表面制备转化膜。通过研究NaF、NH_(4)HF_(2)、KMnO_(4)、十二烷基硫酸钠(SDS)和没食子酸等几种添加剂对转化膜外观与耐蚀性的影响,确定NH_(4)HF_(2)为最佳添加剂。采用电化学方法分析膜层的耐蚀性,用SEM和EDS分析表面形貌及元素组成,并采用XRD和XPS表征膜层晶态结构和化合物组成。基于检测结果,简要分析转化膜的成膜过程。结果最终得到了中性转化处理的最佳成膜工艺为EDTA-2Na8.0g/L,单宁酸1.0g/L,Na_(2)WO_(4)6.0g/L,H_(2)ZrF_(6)4.0g/L,NH_(4)HF_(2)3.0g/L,pH6.6,成膜温度为30℃,成膜时间为15 min。该工艺所制备的转化膜外观致密均匀,颜色为浅黄色。电化学测试结果表明,转化膜具有良好耐蚀性,自腐蚀电流密度由基体铝合金的16.22µA/cm^(2)下降为转化处理后的0.87µA/cm^(2)。EDS能谱分析结果表明,膜层主要由Al、C、F、O、Na、Zr和W元素组成。XRD结果显示,膜层中含有Na_(3)AlF_(6)晶体。XPS分析结果表明,膜层中还含有Al_(2)O_(3)、AlF_(3)、WO_(3)、ZrF_(4)以及金属有机络合物。结论采用中性转化处理工艺,可以在6063铝合金表面制备有色均匀、耐蚀性良好的转化膜,膜层主要由Al的难溶化合物组成。

成膜温度对无铬达克罗涂层结构组成和耐蚀性的影响

[目的]温度对水性无铬达克罗涂层成膜机制的影响尚不明确。[方法]采用KH560硅烷偶联剂作为成膜物,钼酸盐作为钝化剂,片状锌、铝粉作为牺牲阳极组分,制备出一种水性无铬达克罗涂料。采用扫描电镜(SEM)、能谱(EDS)、X射线衍射(XRD)、中性盐雾试验、电化学测量等手段对不同温度(240~600℃)下成膜后涂层的表面形貌、相组成及耐蚀性进行表征与分析。[结果]成膜温度为330℃和390℃时,涂层微观结构最佳,片状锌、铝粉层层叠加,且表面光滑平整,无明显缺陷,经720 h中性盐雾试验后无红锈。成膜温度为330℃时,涂层的腐蚀电流密度最小,极化电阻最大,表现出优异的防护性能。[结论]成膜温度太高或太低都不利于获得耐蚀性良好的无铬达克罗涂层。

甲酸铝改性硫酸铝基无碱液体速凝剂对水泥性能的影响

采用甲酸铝对硫酸铝基无碱液体速凝剂进行改性,并测试了甲酸铝改性后的无碱液体速凝剂性能指标。采用XRD、SEM、TG-DTG和水化热分析表征手段分析了甲酸铝改性硫酸铝基无碱液体速凝剂对水泥水化过程的作用机制。结果表明:随着硫酸铝基无碱液体速凝剂中甲酸铝掺量的增加,水泥的快凝效果和强度均呈先增大后减小的趋势;当改性组分甲酸铝掺量为1%(以硫酸铝质量百分比计)时,掺8%改性硫酸铝基无碱液体速凝剂的水泥初凝时间为2 min 39 s,终凝时间为5 min 33 s,1 d抗压强度为13.2 MPa,28 d抗压强度为49.6 MPa,28 d抗压强度比为114%,90 d抗压强度保留率为123%,满足《喷射混凝土用速凝剂》(GB/T 35159—2017)标准的技术指标要求。当改性组分甲酸铝掺量超过1%时,生成的大量AFt会抑制水泥中C_(3)S的水化反应,导致水泥早期和后期强度降低。

3种免热处理压铸铝合金对模具钢的侵蚀性研究

通过将模具钢浸入熔融铝合金液中并进行动态旋转熔损试验,研究了3种大型一体压铸用免热处理铝合金材料对2种典型压铸模具钢的侵蚀作用。结果表明:经20 min旋转熔损试验后,1#铝合金液中的模具钢表面侵蚀面积最小、质量损失最小、对模具钢的侵蚀最轻,因此,3种免热处理压铸铝合金中,1#铝合金的粘模倾向最小。应用新型免热处理材料时,应选择与该免热处理材料粘模适配性好的模具材料,以获得最小的侵蚀质量损失,保证模具寿命。

改性氮化硼复合材料涂层制备高阻隔导热内衬纸

目的研究液态金属改性氮化硼对无铝内衬纸水蒸气透过性能和导热性能的影响。方法将氮化硼片通过液态金属改性后与聚乙烯醇复合制备功能涂层,涂敷到基纸表面,研究液态金属改性氮化硼的含量和涂层厚度对内衬纸的水蒸气阻隔性能和导热性的影响。结果液态金属改性解决了氮化硼片团聚和基体/填料界面缺陷问题,能够进一步延长水蒸气扩散路径,降低水蒸气透过率,涂层厚度增加进一步延长扩散路径和降低了水蒸气透过率。此外,液态金属改性提升了热导率并降低了弹性模量。结论文中使用功能涂层改善了传统无铝内衬纸的阻隔性和导热性,并降低了模量,有望给兼具柔性、阻隔性和凉感的纸张的制备提供借鉴。

不同Si含量对免热处理强化压铸铝硅合金组织和性能影响的研究

研究了不同Si含量对免热处理强化压铸铝硅合金组织性能影响。结果表明:Al-6%Si合金中的析出相主要沿晶界析出,分布不均匀。其形貌类似杆状,具有尖锐的棱角。随着Si含量提升,析出相所占比重显著上升,并且粒子尺寸增大,同时存有少量未充分溶解的粗大块状初晶硅。在铝硅合金中主要存在两种不同类型的析出相,一种是长针状AlSiFe相,另一种是明亮粗大块状AlSiMnFe相。长针状AlSiFe相具有较高的表面能,能够有足够的空位吸纳Mn原子,从而随着凝固过程进行自发转变为更稳定的块状AlSiMnFe相。在该过程中Mn元素被大量消耗,析出相粒子中的Mn/Fe值下降。随着Si含量的增加,试样的抗拉强度得到了显著提高,但是塑性和抗冲击性能并未协同提升。

硫酸铝型无碱速凝剂的合成及性能评价

喷射混凝土的凝结时间调节与早期强度发展和速凝剂的效能密不可分。本文通过甲酸、十八水硫酸铝、二乙醇胺、六水硝酸镁合成一种新型无碱液体速凝剂ALA,并对其促凝效能与作用机制进行研究。结果表明,ALA具有显著的促凝作用,随着ALA加量的增加,水泥砂浆的初终凝时间分别提前至4.6min和8.2min;ALA具有良好的温度适应性和外加剂相容性,与萘系/聚羧酸系减水剂协同作用时仍能发挥较好的促凝作用;ALA体系中引入的少量Mg^(2+),可与水泥水化产生的OH-结合并生成Mg(OH)_(2),这对固化水泥砂浆的体积收缩有一定的抑制作用;ALA中的Al^(3+)和SO_(4)^(2-)可在水化反应早期诱导大量钙矾石结晶沉积,以形成空间网络结构,促使水泥浆快速凝结。

铝鞣法的演变:从传统技术到绿色制革

铝鞣作为最古老的鞣法之一,一直被用于制革。近年来,由于制革行业面临着Cr(Ⅵ)和含铬固废带来的环境与健康风险,铝鞣法在生态皮革制造中再次被重点关注。本文全面综述了铝鞣技术的研究现状,具体包括铝单独鞣、植-铝结合鞣、铝与其他鞣剂结合鞣以及新型铝鞣技术;对未来铝鞣技术的发展方向进行了展望,有助于生态皮革制造技术的发展。

铝合金阳极氧化膜低温无镍封孔工艺及其封孔性能

为克服传统沸水封孔高能耗和镍盐封孔污染环境的不足,研制了一种无镍低温封孔工艺,其工艺为:锂盐20~30 g/L,氟锆酸盐3.0~5.0 g/L,表面活性剂1.0~2.0 g/L,有机添加剂N 2.0~4.0 mL/L,温度35~55℃,pH 5.0~5.4,封闭时间宜控制在2~3 min/μm。通过酸浸蚀失重试验和电化学试验法对封孔质量和封孔膜的耐蚀性进行评价。结果表明:采用配制的低温无镍封孔剂进行封闭,膜层酸浸蚀失重<30 mg·dm-2,电化学性能明显改善,其封孔效果优于沸水封孔,略差于常温镍盐封孔。