Formation Model of Alumina in the Course of Directed Oxidation of Aluminum Magnesium Alloy

By analyzing the characteristics of magnesium volatilization and linear growth kinetic of Al/ Al_2O_(3 )in directed oxidation of Al-Mg alloy, as the formation process of MgO is considered to be the process of which Al_2O_(3)dissolved in the scale MgO and MgO is partially n-type oxide, formation condition of Al_2O_(3)is established easily in the coure of oxidation. Volatilization of magnesium is to promote the growth of p-type MgO in the surface layer and the formation of Al_2O_(3 )in the inner layer of n-type MgO, and to promote the transformation of MgO toMgAl_2O_(4).MgAl_2O_(4)plays an important role in the formation process of Al_2O_(3), growth stress between MgO and MgAl_2O_(4)cause the formation of cavity in the MgAl_2O_(4 )and aluminum alloy melts is easier to transfer to oxidation front by means of this cavity. The transformation velocity ofMgO to MgAl_2O_(4 )depends on growth kinetic of Al_2O_(3),the faster transformation velocity of MgO to MgAl_2O_(4)is main reason that growth kinetic of Al/Al_2O_(3)transformation exhibits linear relationship.     

The Calculation of Section of Al2O3-CaO-SiO2 System and Its Verification

The basic phase is selected according to the measured phase diagram, two isothermal sections and two vertical sections of the Al 2O 3-CaO-SiO 2 ternary system are calculated using FACT software. The sections in the same conditions are described through the measured phase diagram. Because of the complexity of this ternary system, there is a large difference between the measured and the calculated phase diagram. It is necessary for FACT to ameliorate the calculation model and perfect the database in calculating oxide system which the interaction is strong. For this kind system, the isothermal section and vertical section should be founded through the experiment result and referencing the calculated phase diagram at the same time.     

Formation of Zinc Oxide in the Course of Directed Nitriding With Aluminum Zinc Alloy

ZnO is formed in the course of directed nitriding with Al-Zn alloy, and that the effect of zinc and magnesium on the directed nitriding process is big different. The long fibers which diameter are far less than one micrometer, short bar-like and tetrapod-like zinc oxide is obtained. The three important stages of initial growth kinetic of ZnO approving ZnO have growth mechanism of VS, they are stage of accelerating, linear and parabola, are discovered. Experimental results show that the volatilization of zinc play a very important role in the growth of ZnO,the growth of ZnO is controlled by the diffusion of zinc in the Al-Zn alloy , and the morphologies of ZnO is depend on the saturation level of the vapour.     

中国食品中重金属危害现状及检测技术研究

食品重金属污染一直是影响中国食品质量的主要因素之一,为了保证食品的质量安全,中国制定了食品中污染物限量标准。对中国主要食品中重金属限量标准以及重金属污染情况和常规检测方法进行了介绍,并且对快速检测食品中重金属的技术包括试剂比色检测法,重金属快速检测试纸法,电化学技术快速检测法和酶抑制法进行了简述。最后从严格控制重金属源头,加强治理;加强快速检测技术和方法的研究;政府管理部门应加强监管力度;引入食品重金属风险评估体系等四方面提出了建议,旨在为中国食品重金属的检测、监督和管理等提供参考。     

Al2O3含量对烧结初始液流动行为的影响

在铁矿粉烧结过程中,初始液相流动行为是烧结矿固结效果的重要影响因素。采用微型烧结法,探讨了Al2O3含量对初始液相流动行为的影响,并通过对初始液相微观结构的解析,揭示了Al2O3含量对初始液相气孔分布和结构的影响规律。实验结果表明,初始液相的流动性指数随着Al2O3含量提高而降低。水淬试样的XRD实验结果结果证实,Al2O3含量的增加提高了复合铁酸钙的稳定性,降低了初始液相的流动能力。此外,初始液相流动性亦会对气孔性质产生影响。高Al2O3初始液相中气孔结构不规则程度提高,且小于50 μm气孔数目也随之增多。     

Research of Al2O3 influences on the abrasion resistance of E-coatings on magnesium alloy

The cathodic electrodeposition coatings(E-coatings) with silane modifying ceramics are prepared on magnesium alloy for improving the abrasion resistance of organic E-coating. Hardness, adhesion, corrosion resistance, circle-drawing method and abrasion resistance are evaluated by pencil hardness, UMT abrasion test system, and Machu test. The results show that the abrasion resistance and hardness of E-coatings are enhanced by adding Al2O3 ceramic powders. Meanwhile, corrosion resistance and adhesion of E-coatings remain unchanged.     

铝胁迫下大豆根尖细胞铝的微区分布与耐铝性分析

以浙春3号为实验材料, 利用透射电镜(TEM: Transmission Electron Microscope)-X-射线能谱(EDS: Energy Dispersive X-ray), 调查铝胁迫下大豆根尖铝的微区分布及耐铝性。结果表明,Al³⁺胁迫导致根尖细胞细胞壁不规则加厚, 线粒体数量增多, 核膜膨胀, 液泡中存在较多的电子致密沉淀物。90 mg L^-1 Al³⁺处理的根尖细胞内含物完全降解消失, 仅剩细胞壁。10 mg L^-1 Al³⁺处理的线粒体、细胞壁和液泡电子致密沉淀物中均检测到Al;随着Al³⁺处理浓度的增大, 各细胞器中Al的质量和原子数百分比逐渐增大。线粒体在60 和90 mg L^-1Al³⁺处理下, 液泡电子致密沉淀物在90 mg L^-1Al³⁺处理下,均未被检测出Al。在60 mg L^-1Al³⁺处理下唯一一次在细胞核中检测到Al。Al³⁺抑制了根系生长, 根系细胞中细胞壁的Al³⁺含量受影响最明显。P/Al在细胞壁和线粒体中的相对原子数随Al³⁺浓度的增大而下降。研究结果表明X–射线能谱对铝在亚显微结构上的定位是一种快速、有效的方法。铝最先积累在细胞壁上, 随Al³⁺处理浓度增大逐渐积累于部分细胞器和细胞核中, 且含量在细胞中的分布亦由外向里呈递减趁势。     

Analysis on the Bioleaching Mechanism of Heavy Metal in Sludge by Composite Thiobacillus

The variation of heavy metal speciation during the bioleaching of sludge were carried out. By virtue of heavy metal speciation transformation pattern, the transformation mechanism of heavy metal speciation during the bioleaching could be judged indirectly. The test results show that the bioleaching process of Cu, Ni, Cd are mainly dominated by direct mechanism, the bioleaching process of Zn is mainly dominated by indirect mechanism, and bioleaching process of Cr, Pb are mainly dominated by combined mechanism, while the chemical principle between Cr and Pb are different.     

CO2-O2混合喷吹对铁液中C、V元素氧化的影响

为了验证用CO2替代部分O2进行转炉氧化提钒的可行性,在实验室进行了CO2-O2混合喷吹提钒模拟实验。结果显示C的氧化量与C的氧化速率随CO2含量的增加而升高;V的氧化量随CO2含量的增加而降低,其中CO2含量为20%与纯O2对C、V的氧化量接近;纯O2喷吹时C的氧化量为34.56%,V的氧化量为96.85%;CO2含量为20%混合气体喷吹时C的氧化量为36.83%,V的氧化量为93.29%;以V的相对氧化量与C的相对氧化量的比值(ΔV/ΔC)来衡量提钒保碳能力,CO2含量为20%的最终ΔV/ΔC为5.96,CO2含量,40%、60%、80%的最终ΔV/ΔC均小于3.8;反应前期,V的氧化速率随CO2含量的增加而升高,反应后期V的氧化速率随CO2含量的增加而降低。     

复合岩体的TBM破岩机理数值模拟

为了指导TBM刀盘刀具的研制和不同地质条件下刀盘刀具的选型,TBM破岩机理的研究成为核心。在TBM滚刀的作用下,岩体中裂纹的生成、扩展和连接规律是深刻理解TBM破岩机理的前提,因此,TBM滚刀破岩机理的研究具有重要的工程应用价值。目前,TBM滚刀破岩机理的研究主要集中在单一岩体中,但在TBM施工过程中会遇到各种复杂的地质条件。笔者采用离散元方法,研究了复合岩体的破岩机理,复合岩体中岩片的形成不同于单一岩体,其裂纹的最终连接是由起裂于复合岩体交界面上的微裂纹的扩展,将两滚刀之间的赫兹裂纹连接,最终形成岩片。因此,在一定情况下复合岩体更有利于TBM隧道施工。     

Catalytic Performance of H3PW12O40-TiO2/bentonite in Photocatalytic Degradation of Methyl Orange

H3PW12O40Ti(OH)4 hydrogel was prepared by the sol-gel method, and then H3PW12O40TiO2/bentonite was prepared through the intercalation of H3PW12O40Ti(OH)4 into interlayer space. The characterization of XRD, SEM and EDS showed that H3PW12O40TiO2 species were successfully immobilized on bentonite, and the layer strucure of bentonite was changed. The discrete anatase TiO2 existed on the bentonite. H3PW12O40TiO2/bentonite was a composite material with the different particle size and th loose structure. The photocatalytic degradation of methyl orange showed that the photocatalytic activity of catalyst had been better by doping H3PW12O40, and the H3PW12O40/TiO2/bentonite had a wide applicable range of pH value. Moreover, H3PW12O40TiO2/bentonite had a good catalytic stability. Based on the results of characterization analysis and catalytic performance, the schematic procedure for the action mechanism of H3PW12O40TiO2/Bentonite in photocatalysis was presented.     

The removal efficiency of algal intracellular organic matter in Tai Lake by UV/immobilized TiO2

The immobilized TiO2 film loaded on fiberglass mesh is prepared by sol-gel method, and the analysis result of X-ray diffraction (XRD) shows that the crystalline phase is anatase. On the basis of UV/TiO2 system, the degradation results and effect factors of algal intracellular organic matter(IOM) in Tai Lake are studied. The results show that the degradation of IOM is much harder by photocatalytic oxidation in comparison with humic acid(HA). In 60 min, the IOM degradation of UV254 and DOC are 33.3% and 19.1%, but the HA solution are 96.6% and 57.3% respectively. The reason lies in that IOM is mainly comprised of macromolecular hydrophilic organic matter, containing more amino structures, while HA is strongly hydrophobic organic matter, containing more aromatic structures. Meanwhile, the degradation of IOM is improving as the increase of light intensity to a certain extent; the best degradation rate of IOM appears at pH=6.7.     

Determination of Adulteration Dye Auramine O in Gegen Qinlian Tablets by HPLC-MS/MS

[Objectives]This study aimed to establish a method for determination of adulteration dye auramine O in Gegen Qinlian tablets by HPLC-MS/MS.[Methods]The instrume...     

Vanadium extraction from molten vanadium slag with high contents of Ca and P by direct oxidation and adding Na2CO3 and water leaching method

The mineral phases of the clinker obtaining after oxidizing vanadium slag with high contents of Ca and P are analyzed by X-ray diffraction (XRD), and the experimental parameters of vanadium extraction are also investigated in this paper. The results show that V exists in the form of Na4V2O7, Na3VO4, Na1.33V2O5 and NaCaVO4 when the amount of added Na2CO3 is relatively small (35%). But, with the added Na2CO3 amount increasing, Na4V2O7 and NaCaVO4 react with Na2CO3, then change into Na3VO4. P in the clinker exists in the form of Na3PO4. The leaching rate of vanadium can reach above 90% under the conditions: added Na2CO3 amount of 40%, liquid to solid ratio of 5∶1 mL/g, leaching temperature of 90℃, leaching time of 4 min, stirring rate of 150 r/min. Therefore, the method of extracting vanadium from molten vanadium slag with high contents of Ca and P by direct oxidation and adding Na2CO3 and water leaching is feasible.     

Evaluation of F2 and F3 plants introgressed with QTLs for clubroot resistance in cabbage developed by using SCAR markers

Clubroot disease caused by Plasmodiophora brassicae is one of the major diseases of Brassica crops, often devastating to the cultivation of cruciferous crops in temperate regions. In a previous study (Moriguchi et al. 1999) identified three major quantitative trait loci (QTLs) for clubroot resistance, each in a separate linkage group, in a population derived from a cross between a clubroot‐susceptible inbred cabbage line, Y2A and a resistant inbred kale line, K269. In this study, the original random amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP) markers were converted into sequence‐characterized amplified region (SCAR) markers to facilitate large‐scale marker‐assisted screening of clubroot resistance in cabbage breeding. Of 15 RAPD markers closely linked to the three QTLs, nine SCARs were developed as dominant markers after cloning and sequencing. In addition, two RAPD markers were converted into co‐dominant cleaved amplified polymorphic sequence (CAPS) markers, and one RFLP marker out of three tested was converted to a dominant SCAR marker. The effect of selection for resistance by the improved markers was evaluated in progeny plants in the F2 and F3. A total of 138 F2 plants were genotyped with nine SCARs and 121 well‐distributed makers consisting of 98 RAPD, 19 RFLP, two isozymes, and two morphological markers in order to estimate the level of resistance and the proportion of undesirable alleles from the kale in non‐target areas in each of the F2 populations. An F2 plant, YK118, had kale alleles at QTL1, QTL3 and QTL9. Three F2 plants, namely, YK107, YK25 and YK51 had kale alleles at only QTL1, QTL3 and QTL9, respectively. These F2 plants were selected for their low proportion of alleles derived from kale in non‐target regions. YK118, like the resistant kale parent, expressed very high resistance to three field isolates of Plasmodiophora brassicae, whereas the mean disease index in the F2 and F3 plants carrying only single QTLs was intermediate. The QTLs showed no differential response to the isolates. These plants with improved resistance will be useful as parental inbred lines for F1 hybrids.     

脉冲电流烧结Al2O3颗粒的广义热弹性分析

脉冲电流烧结过程的颈部形成机理,特别是非导电粉末材料,是需要着重研究的核心问题。以非导电Al₂O₃粉末为研究对象,引入L-S（Lord and Shulman）型广义热弹性方程,初步探究烧结初期非导电粉末颈部局部高温形成以及快速烧结机理。利用Comsol Multiphysics模拟得到脉冲电流烧结过程中颗粒内部的温度场和应力场分布以及烧结颈部的化学势和空位浓度变化规律。数值结果表明,热以波的形式在烧结颈部产生叠加,形成局部高温。化学势变化表明：烧结初期表面扩散占主要作用,空位浓度差的突变使烧结颈部产生局部空位浓度梯度,促进烧结颈长过程,缩短烧结时间。     

Effects of reduced nitrogen input on productivity and N2O emissions in a sugarcane/soybean intercropping system

A seven-year (2009–2015) continuous field experiment was established at the South China Agricultural University in order to identify the effects of sugarcane/soybean intercropping and reduced N rate on ecosystem productivity, yield stability, soil fertility, and N₂O emissions. The randomized block experiment was designed with four cropping patterns (sugarcane monocropping (MS), soybean monocropping (MB), sugarcane/soybean (1:1) intercropping (SB1), and sugarcane/soybean (1:2) intercropping (SB2)) and two rates of N fertilization (300 kg hm⁻² (N1, reduced rate) and 525 kg hm⁻² (N2, conventional rate)). The results showed that the land equivalent ratio (LER) of all intercropping systems was greater than 1 (between 1.10 and 1.84), and the SB2-N1 optimally improved the land utilization rate among all treatments. The cropping patterns and N applied rates had no significant effect on sugarcane yield. The soybean yield was influenced by different cropping patterns because of different planting densities (4, 8 and 16 rows of soybean were plant under SB1, SB2, and MB, respectively) and was adopted in this experiment. In addition, under the SB2 cropping pattern, the soybean yield at the reduced N application rate was higher than that at the conventional N application rate. Wricke’s ecovalence (W_i²), the sustainable yield index (SYI) and the coefficient of variation (CV) were used to evaluate yield stability. Different treatments had no significant effects on sugarcane yield stability, as demonstrated by three indicators (W_i², SYI and CV), which indicated that intercropping with soybean and reduced N rate had no effect on sugarcane yield. For soybeans, the value of W_i² demonstrated that the stability of the intercropping system was higher than its counterpart monocropping system, as SYI and CV values indicated that SB2 had higher stability than SB1. During seven years of experiments, there was no significant difference in the soil fertility between MS and SB patterns. The soybean monocropping had a higher available K, pH and lower available P content than sugarcane inter- and mono-cropping. Different cropping patterns had a slight impact on N₂O emissions and the greenhouse gas intensity (GHGI) value. Higher N input promoted N₂O emissions and increased GHGI values. In conclusion, the present study observed that a 40% reduced nitrogen input combined with intercropping soybeans could maintain sugarcane yield and soil sustainable utilization, and that higher N fertilizer additions induced negative impacts on greenhouse gases emissions. Sugarcane intercropping with soybeans can reduce chemical fertilizer input and simultaneously maintain crop productivity; thus, it can be considered to be a reasonable practice for field management.     

棉花S-腺苷蛋氨酸脱羧酶基因(GhSAMDC2/3/4)的克隆及其诱导表达分析

利用电子克隆结合RT-PCR技术克隆获得陆地棉(Gossypium hirsutum L.)S-腺苷蛋氨酸脱羧酶(S-adenosylmethionine decarboxylase,SAMDC)基因家族3个基因,分别命名为Gh SAMDC2、Gh SAMDC3和GhSAMDC4。序列分析显示,该基因c DNA包含的upstream ORF(u ORF)和main ORF(m ORF)为植物SAMDC基因特征ORF,其中m ORF长度分别为1068 bp、1110 bp和1032 bp,分别编码355、369和343个氨基酸。聚类分析表明,Gh SAMDC2/3蛋白与可可树(Theobroma cacao)SAMDC聚为一类,且Gh SAMDC2与GhSAMDC3蛋白亲缘关系最近;Gh SAMDC4与拟南芥At SAMDC4聚为一类。实时荧光定量PCR分析表明,Gh SAMDC2在茎中表达相对较高,随着纤维发育其表达量不断增加,在纤维发育后期其表达量达到最高;Gh SAMDC2/3/4在不同的胁迫条件下表现出不同的表达模式,Gh SAMDC2受低温和干旱胁迫诱导最强烈,Gh SAMDC3响应盐胁迫显著,Gh SAMDC4受ABA诱导强烈。上述结果为进一步研究棉花SAMDC基因功能奠定了一定基础。     

ZnONPs增敏流动注射化学发光法检测雨水中的H2O2

分析了我国茶叶安全现状,介绍了物联网、溯源系统、射频识别(RFID)技术以及茶叶物联网关键技术,通过RFID及物联网技术整合供应链数据,建立基于RFID及物联网技术的茶叶溯源系统,以实现对茶叶的规范和高效管理,为茶叶质量安全追溯体系的构建提供参考借鉴。