Heavy metal pollution assessment in marine sediments in the Northwest coast of Sabah,Malaysia

Heavy metal contents along the Northwest coast of Sabah were determined to interpret the pollution level in the marine sediment. The metal abundance is regulated by the physico-chemical properties such as the average sediment pH(7.82, 9.00 and 8.99), organic matter(0.62%, 1.60%, and 2.27%), moisture content(25.00%, 29.70%, and 15.00%) and sandy texture in Kota Belud, Kudat and Mantanani Island,respectively. The major elements show Ca>Fe>Mg>Al>Mn for all study sites, while the heavy metals show Ni>Cr>Zn>Cu>Co>Pb, Cr>Ni>Zn>Cu>Pb>Co and Zn>Pb>Cr>Ni, for Kota Belud, Kudat and Mantanani Island, respectively. The pollution degree of heavy metals was evaluated by using the Sediment Quality Assessment(SQA). The SQA parameters indicated none to moderate pollution in Kota Belud that shows Class 0, Class 1 and Class 2 pollution. The parameters also indicated none to low pollution in Kudat and Mantanani Island that show only Class 0 pollution. The enrichment factor(EF) suggested minor to moderately severe metal enrichment by anthropogenic sources in Kota Belud, whereas only minor enrichment in Kudat and Mantanani Island. The modified pollution degree(MCD<1.5) and pollution load index(0 PLI<1) indicating only low pollution level in the marine sediments for all study sites. The objectives of this study are:(1) to determine the physico-chemical parameters of sediments,(2) interpret the heavy metal contents and(3) evaluate the sediment quality.

Effects of Alloying Elements on the Microstructures and Mechanical Properties of Heavy Section Ductile Cast Iron

The effects of alloying elements on the as-cast microstructures and mechanical properties of heavy section ductile cast iron were investigated to develop press die material having high strength and high ductility. Measurements of ultimate tensile strength, 0.2% proof strength, elongation and unnotched Charpy impact energy are presented as a function of alloy amounts within 0.25 to 0.75 wt pct range. Hardness is measured on the broken tensile specimens. The small additions of Mo, Cu, Ni and Cr changed the as-cast mechanical properties owing to the different as-cast matrix microstructures. The ferrite matrix of Mo and Ni alloyed cast iron exhibits low strength and hardness as well as high elongation and impact energy. The increase in Mo and Ni contents developed some fractions of pearlite structures near the austenite eutectic cell boundaries, which caused the elongation and impact energy to drop in a small range. Adding Cu and Cr elements rapidly changed the ferrite matrix into pearlite matrix, so strength and hardness were significantly increased. As more Mo and Cr were added, the size and fraction of primary carbides in the eutectic cell boundaries increased through the segregation of these elements into the intercellular boundaries.

Determination of wholesome elements and heavy metals in safflower(Carthamus tinctorius L.)from Xinjiang and Henan by ICP-MS/ICP-AES

An inductively coupled plasma mass spectrometry （ICP-MS） or inductively coupled plasma atomic emission spectrometry （ICP-AES） was developed to determine 19 elements in safflower, a traditional Chinese medicinal herb from Xinjiang Autonomous Region and Henan Province of China. Totally 19 elements in safflower included heavy metals, i.e. As, Cd, Cu, Hg and Pb, and wholesome elements, i.e. Al, Ca, Co, Cr, Fe, Mg, Mn, Mo, Ni, P, Se, Sr, V and Zn. The results showed that the concentrations of heavy metals in safflower samples were both low, all of which met the national hygiene standards except for Pb in Xinjiang sample. Meanwhile, the distribution tendency of elements in the two samples was similar, which indicated that the plant might absorb given elements in a proportional way. The method can be used for the quality control of elements in safflower, and it provides a way for the determination of the contents of safflower from Xinjiang and Henan.

Heavy ion and X-ray irradiation alter the cytoskeleton and cytomechanics of cortical neurons

Heavy ion beams with high linear energy transfer exhibit more beneifcial physical and biological performance than conventional X-rays, thus improving the potential of this type of radiotherapy in the treatment of cancer. However, these two radiotherapy modalities both cause inevitable brain injury. The objective of this study was to evaluate the effects of heavy ion and X-ray irra-diation on the cytoskeleton and cytomechanical properties of rat cortical neurons, as well as to determine the potential mechanism of neuronal injury after irradiation. Cortical neurons from 30 new-born mice were irradiated with heavy ion beams at a single dose of 2 Gy and X-rays at a single dose of 4 Gy;subsequent evaluation of their effects were carried out at 24 hours after irradiation. An immunolfuorescence assay showed that after irradiation with both the heavy ion beam and X-rays, the number of primary neurons was signiifcantly decreased, and there was ev-idence of apoptosis. Radiation-induced neuronal injury was more apparent after X-irradiation. Under atomic force microscopy, the neuronal membrane appeared rough and neuronal rigidity had increased. These cell changes were more apparent following exposure to X-rays. Our ifnd-ings indicated that damage caused by heavy ion and X-ray irradiation resulted in the structural distortion and rearrangement of the cytoskeleton, and affected the cytomechanical properties of the cortical neurons. Moreover, this radiation injury to normal neurons was much severer after irradiation with X-rays than after heavy ion beam irradiation.

All-electron ZORA triple zeta basis sets for the elements Cs-La and Hf-Rn

Segmented all-electron basis set of triple zeta valence quality plus polarization functions(TZP)for the elements of the fifth row to be used together with the zero-order regular approximation(ZORA)is carefully constructed.To correctly describe electrons distant from atomic nuclei,the basis set is augmented with diffuse functions giving rise to a set designated as ATZP-ZORA.At the ZORA-B3LYP theoretical level,these sets are used to calculate the ionization energy and mean dipole polarizability of some atoms,bond length,dissociation energy,and harmonic vibrational frequency of diatomic molecules.Then,these results are compared with the theoretical and experimental data found in the literature.Even considering that our sets are relatively compact,they are sufficiently accurate and reliable to perform property calculations involving simultaneously electrons from the inner shell and outer shell.The performances of the ZORA and second-order Douglas-Kroll-Hess Hamiltonians are evaluated and the results are also discussed.

All-electron basis sets for H to Xe specific for ZORA calculations:Applications in atoms and molecules

A segmented basis set of quadruple zeta valence quality plus polarization functions(QZP)for H through Xe was developed to be used in conjunction with the ZORA Hamiltonian.This set was augmented with diffuse functions to describe electrons farther away from the nuclei adequately.Using the ZORA-CCSD(T)/QZP-ZORA theoretical model,atomic ionization energies and bond lengths,harmonic vibrational frequencies,and atomization energies of some molecules were calculated.The addition of core-valence corrections has been shown to improve the agreement between theoretical and experimental results for molecular properties.For atomization energies,a similar observation emerges when considering spin-orbit couplings.With the augmented QZP-ZORA set,static mean dipole polarizabilities of a set of atoms were calculated and compared with previously published recommended and experimental values.Performance evaluations of the ZORA and Douglas–Kroll–Hess Hamiltonians were made for each property studied.

Recent Progress in Radiative-Rate Determination of Some Heavy Ions (Xe⁹⁺, Xe¹⁰⁺, Lu³⁺, Hf⁴⁺, Ta⁵⁺) of Interest in Fusion

This paper presents a review about the radiative properties (transition probabilities and oscillator strengths) of two xenon ions (Xe9+, Xe10+) and three members of Er I isoelectronic sequence (Lu3+, Hf4+, Ta5+) of interest in controlled thermonuclear fusion, including our recent theoretical data obtained using two independent theoretical atomic structure computational approaches (semi-empirical Hartree-Fock with relativistic corrections method (HFR) and the ab initio multiconfiguration Dirac-Hartree-Fock (MCDHF)). The tables, from the second one, summarize the recommended data expected to be useful for plasma modelling in fusion.

基于甘蔗耕地黏土离散元参数标定的流变模型构建

针对华南宿根甘蔗的耕地土壤因多级复合团聚显现的逐层异构黏重性,为表征其特异性流变行为,该研究通过重黏土的离散元参数标定,构建团粒几何、力学属性多层演变的非匀质耕层模型,进而分析仿生壁板的推进阻力。结合休止角与三轴压缩试验及仿真结果,JKR表面能、恢复系数与动摩擦因数是影响重黏土流变响应的显著因子,不同耕层间参数差异明显。蕴含团粒级配分布、本征接触属性与黏聚特性的离散元模型具有表征多耕层复合流变性能的能力,通过三轴力学试验验证得到的本构响应偏差低于9.27%。采用该模型计算出的仿生耕作壁板推进阻力与土槽实测推进阻力之间的相对误差仅8.3%,表明对机具—土料互作关系的预测有效且较准确。研究结果可为触土部件适应性设计与动力学优化提供数据支持和模型参考。

土壤化学性质对土壤及宝坻大蒜鳞茎中重金属元素含量的影响

为了解土壤化学性质对土壤和植物系统中重金属元素迁移和积累的影响,以天津宝坻大蒜种植区为例,通过对土壤中pH、阳离子交换量、有机质、阴离子、SiO_(2)含量的测定以及对土壤和大蒜中重金属元素Cr、Cu、Ni、Pb、Zn、Cd、As、Hg含量的分析,将所得数据利用SPSS进行相关性分析和多元回归分析。结果表明:Ni在表层土、深层土、鳞茎、植株四类介质中呈显著正相关,Cu在表层土、鳞茎、植株三类介质中呈显著正相关,Cr、Cd在表层土、深层土两类介质中呈显著正相关,Zn、As在鳞茎、植株两类介质中呈显著正相关。这表明以上元素在不同介质间的转化运移存在密切联系。土壤pH、SiO_(2)含量等因素对大蒜鳞茎中Cu、Cd的吸收和积累具有显著的影响,硫酸根离子(SO_(4)^(2-))对土壤和大蒜系统中As、Cu、Ni、Zn有明显的调控作用。综上,本研究为农业管理和环境保护提供了重要的参考信息。

原子吸收光谱分析法检测复方龙血竭胶囊中重金属含量

目的:为检测复方龙血竭胶囊中重金属残留量。方法:采用原子吸收分光光度法测定复方龙血竭胶囊中的Pb、Cd、Cu、As、Hg含量,并利用标准曲线测定3个批次复方龙血竭胶囊中重金属的含量。结果:复方龙血竭胶囊中Pb、Cd、Cu、As含量分别为0.23、0.32、0.51 mg/kg;0.05、0.08、0.06 mg/kg;0.05、0.04、0.04 mg/kg;0.26、0.58、0.40 mg/kg;0.01、0.02、0.03 mg/kg;Hg元素含量未检出。结论:复方龙血竭胶囊中Pb、Cd、Cu、As、Hg等5种重金属含量均符合2020版《中国药典》标准要求,安全性较好。

原子吸收光谱分析法检测虎力散胶囊中重金属含量

为了检测虎力散胶囊中重金属残留量,采用原子吸收分光光度法测定虎力散胶囊中的Pb、Cd、Cu、As、Hg,并利用标准曲线法计算3个不同批次虎力散胶囊中重金属的含量。测定结果得到,虎力散胶囊中Pb、Cd、Cu、As、Hg含量分别为1.59、1.95、1.66mg/kg;0.19、0.28、0.17mg/kg;0.21、0.32、0.22mg/kg;0.64、0.38、0.41mg/kg;0.01、0.02、0.03 mg/kg,虎力散胶囊中Pb、Cd、Cu、As、Hg等5种重金属含量均符合2020版《中国药典》标准要求,安全性较好。

Growth, Metabolism and Yield of Rice Cultivated in Soils Amended with Fly Ash and Cyanobacteria and Metal Loads in Plant Parts

Soil amendment with fly ash（FA） and combined supplementation with N_2-fixing cyanobacteria masses as biofertilizer were done in field experiments with rice. Amendments with FA levels, 0, 0.5, 1.0, 2.0, 4.0, 8.0 and 10.0 kg/m2, caused increase in growth and yield of rice up to 8.0 kg/m2, monitored with several parameters. Pigment contents and enzyme activities of leaves were enhanced by FA, with the maximum level of FA at 10.0 kg/m2. Protein content of rice seeds was the highest in plants grown at FA level 4.0 kg/m2. Basic soil properties, p H value, percentage of silt, percentage of clay, water-holding capacity, electrical conductivity, cation exchange capacity, and organic carbon content increased due to the FA amendment. Parallel supplementation of FA amended plots with 1.0 kg/m2 N_2-fixing cyanobacteria mass caused further significant increments of the most soil properties, and rice growth and yield parameters. 1000-grain weight of rice plants grown at FA level 4.0 kg/m2 along with cyanobacteria supplementation was the maximum. Cyanobacteria supplementation caused increase of important basic properties of soil including the total N-content. Estimations of elemental content in soils and plant parts（root and seed） were done by the atomic absorption spectrophotometry. Accumulations of K, P, Fe and several plant micronutrients（Mn, Ni, Co, Zn and Cu） and toxic elements（Pb, Cr and Cd） increased in soils and plant parts as a function of the FA gradation, but Na content remained almost unchanged in soils and seeds. Supplementation of cyanobacteria had ameliorating effect on toxic metal contents of soils and plant parts. The FA level 4.0 kg/m2, with 1.0 kg/m2 cyanobacteria mass supplementation, could be taken ideal, since there would be recharging of the soil with essential micronutrients as well as toxic chemicals in comparative lesser proportions, and cyanobacteria mass would cause lessening toxic metal loads with usual N_2-fixation.

轧后控冷对重型H型钢组织和性能的影响

在重型H型钢生产中,轧制变形后的冷却过程是最终组织控制最为重要的途径。本文对重型H型钢轧后冷却过程进行有限元模拟和轧制实验研究。结果表明,采用轧后控冷工艺会在实验钢表面形成大量的回火索氏体;水冷时间从22 s增加到30 s,实验钢表面返温温度逐渐降低,回火组织层厚度增大,实验钢强韧性提高。当水冷时间为30 s时,返温温度达到650℃,在这个条件下实验钢获得最佳的力学性能。

高寒矿区人工建植草地和自然草皮移植生态修复效应

高寒高海拔矿山经过多年开采后生态系统破坏严重,生态修复困难重重,本文以地处青藏高原东南缘海拔高于4300 m的西藏某铜矿为例,探讨高海拔矿产开发工程人工建植和自然草皮移植生态修复效应。结果表明:1)高寒草甸矿区排土场采取生态修复后,人工建植草地草本层平均高度增加,植物盖度下降,植物丰富度指数、多样性指数和均匀度指数均降低,与天然植被相比,人工建植植被群落出现自我更新现象,移植自然草皮植被群落出现退化现象。2)高寒矿区天然草地土壤有机质、全氮、有效磷和速效钾含量较高,矿区生态修复后土壤中各养分含量指标下降。与天然草地相比,人工建植草地土壤有机质、全氮、有效磷和速效钾含量分别下降39.67%、31.56%、67.83%和14.40%,自然草皮移植草地土壤中各指标分别下降72.30%、72.29%、61.62%和6.77%。3)天然草地土壤为中性,矿区土壤重建生态修复后土壤呈碱性,人工建植草地和自然草皮移植草地土壤pH分别增加15.71%和11.43%。4)与天然草地相比,自然草皮移植草地土壤重金属汞(Hg)、砷(As)、铅(Pb)、锌(Zn)和镍(Ni)含量均显著增加,而人工建植草地各重金属元素含量没有显著变化,表明草皮移植生态修复措施,加大了土壤重金属元素污染的风险。

微波消解-原子荧光法检测液奶中砷和汞样品前处理方法探究及应用

为准确检测牛奶中重金属含量,采用微波消解-原子荧光法检测牛奶中的重金属元素砷和汞,通过单因素和正交实验,以加标回收率为指标优化其检测方法,并对方法进行验证和应用。结果表明,砷和汞的最佳检测条件为还原剂硫脲的浓度为50 g/L、硼氢化钾-氢氧化钾的浓度15 g/L,氨基磺酸的添加量为2.5 mL,硝酸的添加量为5 mL、微波消解温度为195℃。砷和汞的检出限分别为0.01 mg/kg、0.003 mg/kg;标准曲线方程线性范围分别为0~10 ng/mL、0~1 ng/mL,相关系数分别为0.997、0.992;砷和汞的加标回收和质控样本的检测数据重现性RSD分别为0.11、0.18、3.82、4.29,精密度分别为0.59、0.56、3.28、4.32;一个季度砷、汞加标回收率和质控样本共检测48次,回收率分别为98.84%、99.23%,RSD为1.01、1.91。质控样本检测值偏差符合实验要求,RSD为2.79~3.80。回收率和质控值偏差均符合国家标准要求。成功建立同时检测砷和汞的便捷、准确灵敏的原子荧光检测方法,为监管食品受重金属污染奠定基础。

原子吸收光谱法在食品重金属元素检测中的应用

近年来,食品安全备受关注,特别是重金属元素对人体健康的潜在威胁引起了广泛关注。重金属元素如铅、镉、汞等在人体中长期积累可能导致慢性中毒,因此对食品中重金属元素进行快速、准确的检测显得尤为重要。原子吸收光谱法作为一种应用较广泛的食品检测分析技术,具有快速、准确、灵敏度高的特点。通过原子吸收光谱法,可以对食品样品中的微量重金属元素进行定量分析,为食品质量安全提供了有力的技术支持。因此,本文旨在探讨原子吸收光谱法在食品重金属元素检测中的应用,阐明该方法在食品安全监测中的重要作用,为食品安全领域的研究和实践提供有益参考。

微波消解-原子荧光光谱法测定铁皮石斛中的重金属元素

本文建立了微波消解-原子荧光光谱法测定铁皮石斛中重金属的分析方法。优化了微波消解条件,同时对方法学进行了验证。结果表明,消解剂为硝酸-盐酸混合酸,以5∶2(体积比)为最佳配比,砷、汞、铅线性范围分别为1.0~100.0μg·L^(-1)、0.4~10.0μg·L^(-1)、1.0~50.0μg·L^(-1),检出限分别为0.0162μg·mL^(-1)、0.0048μg·mL^(-1)、0.5311μg·mL^(-1),加标回收率为94.6%~109.7%。微波消解-原子荧光光谱法能够满足铁皮石斛中重金属含量的测定。

陈皮、淡竹叶等5种药材重金属含量分析

采用微波消解法处理竹叶青酒配方的5种中药材(陈皮、淡竹叶、檀香、栀子、当归),然后利用原子吸收光谱法和原子荧光光谱法测定这5种中药材铜、镉、铅、砷、汞元素的含量。结果表明,样品中5种重金属元素的含量均未超过《中国药典》2020版限量规定,各个元素线性相关性好,检出限低,准确度高。该方法可为药材中重金属元素的检测及公司产品生产原料的质量控制提供参考。

川贝母中重金属元素的测定方法研究

建立了微波消解-原子荧光光谱法测定川贝母中重金属的分析方法。考察了消解剂类型、用量以及载流酸度和还原剂浓度对测定结果的影响,最终确定硝酸-盐酸混合酸为消解剂,将其体积比(5∶2)作为最佳用量配比,载流浓度为5%,还原剂浓度为2%。实验结果表明,砷、汞、铅线性范围为1.0~100.0μg·L^(-1)、0.4~10.0μg·L^(-1)、1.0~50.0μg·L^(-1),检出限为0.0162μg·L^(-1)、0.0048μg·L^(-1)、0.5311μg·L^(-1),加标回收率在95.3%~107.7%,能够满足川贝母中重金属含量的测定。

一种快速测定土壤中重金属元素的方法确认

通过优化试验的关键步骤得到一种快速准确测定土壤中重金属元素铬、铅、镍、铜、锌的方法,对该方法进行确认。结果表明:采用该方法测定重金属元素的检出限为1.40~7.30 mg/kg,精密度为1.64%~5.10%,低浓度平均加标回收率为91.2%~106.4%,高浓度平均加标回收率为93.9%~108.6%。该方法检测效率高、精密度好、检出限低、回收率高,可用于土壤中重金属污染的监控与快速溯源。