过量重金属元素对动物生理毒性及作用机制的研究进展

饲料中重金属元素添加不当或过度使用会对动物生理健康造成极大的危害。过量重金属元素可对动物的机体组织、免疫系统、繁殖能力与生产性能产生负面影响。过量重金属元素的毒性主要表现为改变动物体内信号通路、诱发机体氧化应激以及对动物神经产生损伤。文章旨在分析过量重金属对动物健康的影响,探讨过量重金属的毒性作用及机制,为实际生产提供参考。

The application of metal-organic frameworks and their derivatives for lithium-ion capacitors

There is an urgent need for lithium-ion capacitors(LICs)that have both high energy and high power densities to meet the continuously growing energy storage demands.LICs effectively balance the high energy density of traditional rechargeable batteries with the superior power density and long life of supercapacitors(SCs).Nevertheless,the development of LICs is still hampered by limited kinetic processes and capacity mismatch between the cathode and anode.Metal-organic frameworks(MOFs)and their derivatives have received significant attention because of their extensive specific surface area,different pore structures and topologies,and customizable functional sites,making them compelling candidate materials for achieving high-performance LICs.MOF-derived carbons,known for their exceptional electronic conductivity and large surface area,provide improved charge storage and rapid ion transport.MOF-derived transition metal oxides contribute to high specific capacities and improved electrochemical stability.Additionally,MOF-derived metal compounds/carbons provide combined effects that increase both the capacitive and Faradaic reactions,leading to a superior overall performance.The review begins with an overview of the fundamental principles of LICs,followed by an exploration of synthesis strategies and ligand selection for MOF-based composite materials.It then analyzes the advantages of original MOFs and their derived materials,such as carbon materials and metal compounds,in enhancing LIC performance.Finally,the review discusses the major challenges faced by MOFs and their derivatives in LIC applications and offers future research directions and recommendations.

浅谈非整比化合物

金属过量、金属短缺缺陷。

Species Transformation of Trace Elements and Their Distribution Prediction in Dyestuff Residue Incineration

The release of heavy metals from the combustion of hazardous wastes is an environmental issue of in-creasing concern.The species transformation characteristics of toxic heavy metals and their distribution are consid-ered to be a complex problem of mechanism.The behavior of hazardous dyestuff residue is investigated in a tubular furnace under the general condition of hazardous waste pyrolysis and gasfication.Data interpretation has been aided by parallel theoretical study based on a thermodynamic equilibrium model based on the principle of Gibbs free en-ergy minimization.The results show that Ni,Zn,Mn,and Cr are more enriched in dyestuff residue incineration than other heavy metals(Hg,As,and Se)subjected to volatilization.The thermodynamic model calculation is used for explaining the experiment data at 800℃ and analyzing species transformation of heavy metals.These results of species transformation are used to predict the distribution and emission characteristics of trace elements.Although most trace element predictions are validated by the measurements,cautions are in order due to the complexity of incineration systems.

巧解天平平衡题“量递增法”

笔者根据自己的实践，总结出解天平平衡题的一种方法“量递增法”。例１：在天平的两个托盘上各放一个盛有Ａｍｏｌ硫酸的烧杯，调节天平使其平衡，然后，在一个烧杯里加入Ｍｇ铁粉，另一个烧杯里加入Ｎｇ镁粉，充分反应后，天平仍保持平衡，请用代数式表示Ｍ、Ｎ、Ａ之间...

Structural Evolution and Electronic Properties of Au2Gen-/0（n=1-8） Clusters: Anion Photoelectron Spectroscopy and Theoretical Calculations

Investigating the structures and properties of Au-Ge mixed clusters can give insight into the microscopic mechanisms in gold-catalyzed Ge films and can also provide valuable information for the production of germanium-based functional materials. In this work, size-selected anion photoelectron spectroscopy and theoretical calculations were used to explore the structural evolution and electronic properties of Au2Gen^-/0 (n=1-8) clusters. It is found that the two Au atoms in Au2Gen^-/0 (n=1-8) showed high coordination numbers and weak aurophilic interactions. The global minima of Au2Gen- anions and Au2Gen neutrals are in spin doublet and singlet states, respectively. Au2Gen- anions and Au2Gen neutrals showed similar structural features, except for Au2Ge4^-/0 and Au2Ge5^-/0. The C2v symmetric V-shaped structure is observed for Au2Ge1^-/0, while Au2Ge2^-/0 has a C2v symmetric dibridged structure. Au2Ge3^-/0 can be viewed as the two Au atoms attached to different Ge-Ge bonds of Ge3 triangle. Au2Ge4- has two Au atoms edge-capping Ge4 tetrahedron, while Au2Ge4 neutral adopts a C2v symmetric double Au atoms face-capping Ge4 rhombus. Au2Ge5-8^-/0 show triangular, tetragonal, and pentagonal prism-based geometries. Au2Ge6 adopts a C2v symmetric tetragonal prism structure and exhibits σ plus π double bonding characters.

Review of Metal AM Simulation Validation Techniques

Due to the complexity of metal AM （additive manufacturing）, it can require many trial runs to obtain processing parameters which produce a quality build. Because of this trial and error process, the drive for simulations of AM has grown significantly. A simulation only becomes useful to researchers if it can be shown that it is a true representation of the physical process being simulated. Each process being simulated has a different method of validation to show it is an accurate representation of the process. This paper explores the various methodologies for validation of laser-based metal AM simulations, focusing mainly on the modeling of the thermal processes and other characteristics derived from the thermal history. It will identify and explain the various validation techniques used, specifically looking at the frequency of reported use of each technique.

Heat and Radiation Generation during Hydrogenation of CH Compound

Securing new sources of energy has become a major concern, because fossil fuels are expected to be depleted within several decades. In some of the major wars of the 20th century, control of oil was either a proximate cause or a decisive factor in the outcome. Especially in Japan and Germany, a great deal of research was devoted to making liquid fuels from coal. In one such experiment, a large amount of excess heat was observed. The present study was devoted to replicating and controlling that excess heat effect. The reactant is phenanthrene, a heavy oil fraction, which is subjected to high pressure and high heat in the presence of a metal catalyst. This results in the production of excess heat and strong penetrating electromagnetic radiation. After the reaction, an analysis of residual gas reveals a variety of hydrocarbons, but it seems unlikely that these products can explain the excess heat. Most of them form endothermically, and furthermore heat production reached 60 W. Overall heat production exceeded any conceivable chemical reaction by two orders of magnitude.

Fungal Absorption and Tolerance of Heavy Metals

Soil, water, sediments and air are frequently contaminated with heavy metals. In Saudi Arabia, heavy metals contamination may result from petroleum and mining operations, refining ores, sludge, waste treatment, electrical equipment, paints, alloys, pesticides, batteries and fuel transportation. Microbial processes lead to appreciable and even complete remediation of heavy metals contaminated environments. The chief ways, by which such remediation may be accomplished, include biosorption, bioaugmentation, bioventing, biostimulation, bioaccumulation, biosolubilization, bioreduction, bioprecipitation, mineralization and methylation. Other technologies and methods are fully developed and now are being used in practice, such as heavy metals nanotechnology bioremediation. An area of fungal biotechnology currently in vogue is the use of fungal biornass to absorb metal ions from contaminated solutions. Such biological approaches of metal ions recovery can be used to clean up polluted effluents or to recover precious metal ions from solutions. The present review provides information on fungal bioremediation of heavy metal contamination for use in future studies in Saudi Arabia as well as in the Arabian Gulf Region.

NiMoCo layered double hydroxides for electrocatalyst and supercapacitor electrode

Non-noble-metal electrode materials with high durability and efficiency have become the frontiers of energy conversion and storage fields.However,conventional electrode materials often show high overpotential and low conductivity.To solve this problem,we fabricate a NiMoxCo2−x layered double hydroxide(LDH)/Ni foam(NF)product through a facile hydrothermal route.The as-prepared NiMo-Co-LDH/NF catalyst possesses an overpotential of 123 mV for hydrogen evolution reaction(HER)at 10 mA cm^−2 and 279 mV for oxygen evolution reaction(OER)at 20 mA cm^−2.The as obtained product exhibits excellent overall water splitting performances.Meanwhile,as the electrode material for supercapacitor,it delivers high specific capacitance and excellent cyclic performance.The asymmetric supercapacitor assembled with NiMoCo-LDH/NF//active carbon exhibits 93%of its initial capacity after 8000 cycles.

Geostatistical Assessment of Pb,Zn and Cd Contamination in Near-Surface Soils of the Urban-Mining Transitional Region of Isfahan,Iran

Due to the lack of regulation and environmental education and awareness, Sepahanshahr located in vicinity of Isfahan City, central Iran, is now a rapid growing residential area suffering from the considerable consequences of poorly regulated mining activities operating in its vicinity. A survey was carried out on soil Pb, Zn and Cd concentrations around Sepahanshahr Town to explore the spatial structure of Pb, Zn and Cd distribution and to map their concentrations using geostatistical techniques. 100 near-surface soil samples were collected and analyzed for Pb, Zn and Cd and some related soil physical and chemical variables such as pH, organic matter content, electrical conductivity, and clay, silt and sand contents. The variography results showed a strong spatial dependency in heavy metals concentration due to the dilution effects of natural factors including atmospheric dispersion and precipitation. The almost same range values calculated for both In-transformed Pb and sand data suggested presence of spatial co-regionalization. However, In-transformed Zn data showed a shorter spatial dependency among the three tested heavy metals. Kriged maps of all three heavy metals showed a strong gradient of contamination around the three mining sites activating in the area. The results of this study provide insight into identification of the extent and spatial variability of Pb, Zn and Cd pollution in the mining sites and surrounding urban areas.

Mn^(2+)-activated calcium fluoride nanoprobes for time-resolved photoluminescence biosensing

Time-resolved (TR)photoluminescence (PL) technique has shown great promise in ultrasensitive biodetection and high-resolution bioimaging.Hitherto,almost all the TRPL bioprobes are based on the parity-forbidden f→f transition of lanthanide ions.Herein,we report TRPL biosensing by taking advantage of the d→d transition of transition metal (TM)Mn^2+ ion.We demonstrate that the Forster resonance energy transfer (FRET)signal can be distinguished from that of radiative reabsorption process through measuring the PL lifetime of Mn^2+,thus establishing a reliable method for Mn^2+ in homogeneous TR-FRET biodetection.We also demonstrate the biotin receptor-targeted cancer cell imaging by utilizing biotinylated CaF2:Ce,Mn nanoprobes.Furthermore,we show in a proof-of-concept experiment the appli- cation of the long-lived PL of Mn^2+ for TRPL bioimaging through the burst shot with a cell phone.These findings provide a general approach for exploiting the long-lived PL of TM ions for TRPL biosensing,thereby opening up a new avenue for the exploration of novel and versatile applications of TM ions.

Bowl-shaped NiCo2O4 nanosheet clusters as electrode materials for high-performance asymmetric supercapacitors

The development of transition metal oxidebased electrode materials with proper controlled structures is highly desirable for high-performance supercapacitors.However,it remains a major challenge.Here,we present the first synthesis of bowl-like Ni Co2O4nanosheet clusters through a simple soft template guided hydrothermal strategy.The resulting bowl-like clusters consist of numerous Ni Co2O4nanosheets with an average thickness of 19 nm and possess a mean diameter of 1μm along with a specific surface area of40 m2g^-1.Remarkably,serving as an electrode material in a three-electrode system,the bowl-like Ni Co2O4nanosheet clusters exhibit a high specific capacity of 1068 F g^-1at a current density of 1 A g^-1and excellent cycling stability with90%capacitance retention after 5000 charge-discharge cycles.Meanwhile,an asymmetric supercapacitor(ASC)assembled with the Ni Co2O4clusters and activated carbon(AC)as the two electrodes exhibits a high specific capacitance of 129 F g^-1at 1 A g^-1,along with a high energy density of 33 W h kg^-1at a power density of 0.66 k W kg^-1.Such performance is superior to those of many commercial supercapacitors.This study opens a new avenue for the construction of ordered complex particles with controlled architectures for energy storage and conversion applications.

我国叠氮化钠生产应用及市场需求

叠氮化钠为无色六方形晶体,溶于水和液氨,微溶于乙醇,不溶于乙醚,加热到410℃时分解成金属钠和氮气。 工业化生产方法主要有以下两种。①金属钠法:该法以过量金属钠和液氨反应,先制取氨基钠,然后在液氨介质中,用氧化氮与氨基钠反应得叠氮化钠。

Direct vapor phase growth process and robust photoluminescence properties of large area MoS2 layers

There has been growing research interest in the use of molybdenum disulfide in the fields of optoelectronics and energy harvesting devices, by virtue of its indirect-to-direct band gap tunability. However, obtaining large area thin films of MoS2 for future device applications still remains a challenge. In the present study, the amounts of the precursors （S and MOO3） were varied systematically in order to optimize the growth of highly crystalline and large area MoS2 layers by the chemical vapor deposition method. Careful control of the amounts of precursors was found to the key factor in the synthesis of large area highly crystalline flakes. The thickness of the layers was confirmed by Raman spectroscopy and atomic force microscopy. The optical properties and chemical composition were studied by photoluminescence （PL） and X-ray photoelectron spectroscopy. The emergence of strong direct excitonic emissions at 1.82 eV （A-exciton, with a normalized PL intensity of -55 × 10^3） and 1.98 eV （B-exciton, with a normalized PL intensity of -5 × 10^3） of the sample at room temperature clearly indicates the high luminescence quantum efficiency. The mobility of the films was found to be 0.09 cm^2/（V.s） at room temperature. This study provides a method for the controlled synthesis of high-quality two-dimensional （2D） transition metal dichalcogenide materials, useful for applications in nanodevices, optoelectronics and solar energv conversion.

Revealing interfacial space charge storage of Li^(+)/Na^(+)/K^(+)by operando magnetometry

Interfacial space charge storage between ionic and electronic conductor is a promising scheme to further improve energy and power density of alkali metal ion batteries(AMIBs).However,the general behavior of space charge storage in AMIBs has been less investigated experimentally,mostly due to the complicated electrochemical behavior and lack of proper characterization techniques.Here,we use operando magnetometry to verify that in FeSe_(2)AMIBs,abundant Li^(+)/Na^(+)/K^(+)(M^(+))can be stored at M_(2)Se phase while electrons accumulate at Fe nanoparticles,forming interfacial space charge layers.Magnetic and dynamics tests further demonstrate that with increasing ionic radius from Li^(+),Na^(+)to K^(+),the reaction kinetics can be hindered,resulting in limited Fe formation and reduced space charge storage capacity.This work lays solid foundation for studying the complex interfacial effect in electrochemical processes and designing advanced energy storage devices with substantial capacity and considerable power density.