Absolute dielectronic recombination rate coefficients of highly charged ions at the storage ring CSRm and CSRe

Dielectronic recombination(DR)is one of the dominant electron-ion recombination mechanisms for most highly charged ions(HCIs)in cosmic plasmas,and thus,it determines the charge state distribution and ionization balance therein.To reliably interpret spectra from cosmic sources and model the astrophysical plasmas,precise DR rate coefficients are required to build up an accurate understanding of the ionization balance of the sources.The main cooler storage ring(CSRm)and the experimental cooler storage ring(CSRe)at the Heavy-Ion Research Facility in Lanzhou(HIRFL)are both equipped with electron cooling devices,which provide an excellent experimental platform for electron-ion collision studies for HCIs.Here,the status of the DR experiments at the HIRFL-CSR is outlined,and the DR measurements with Na-like Kr25^(+)ions at the CSRm and CSRe are taken as examples.In addition,the plasma recombination rate coefficients for Ar12^(+),14^(+),Ca14^(+),16^(+),17^(+),Ni19^(+),and Kr25^(+)ions obtained at the HIRFL-CSR are provided.All the data presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00113.00092.

A Study on the Chess Culture of Ethnic Minority Groups in Gansu Province

As a region inhabited by large populations of ethnic minority groups, Gansu province boasts rich ethnic cultural resources which reflect traditional culture and intangible cultural heritage that had taken shape thousands of years ago. Among these are various ethnic folk chess games. They are time-honored with many types such as the “Fang” chess of the Hui ethnic group, the “Jiu” chess of the Tibetans, the “King and Ministers” chess, the Mongolian chess, the Mongolian military chess, etc. These games embody distinctive ethnic and regional characteristics, as well as the cultural elements of a particular ethnic minority group. It is of great significance, therefore, to study the ethnic chess by collecting, documenting and comparing different types of related chess. The paper explores ways to standardize, protect and promote them scientifically in joint efforts, and draws a conclusion that examining their significance in the present era and the ethnic characteristics is the key to understanding the profound culture behind the chess.

新型冠状病毒肺炎疫情的分级管控对非洲猪瘟防控的启发

新型冠状病毒肺炎疫情传播之快、范围之广,深深地让人们感到震惊,我国防疫工作取得重大阶段性进展,但国外的疫情还在形成蔓延之势。在防控阶段,检测、隔离、诊疗措施的到位是很关键的,对阻断传播、救治患者将带来极大的帮助,对照我国养猪业的猪病防控,其有不少可借鉴之处,如对疫情的分级管理。1第一级--确诊群体新型冠状病毒肺炎疫情的确诊患者以及医护人员、疾控管理人员等,需对其进行重点关注。

Countermeasures and Recommendations for High Quality Development of Tan Sheep Industry in Ningxia

Tan sheep industry is a characteristic and superior agricultural industry in Ningxia,and it is also an enriching industry that helps in poverty alleviation and increases farmers’income.The local government has been committing to building the"Yanchi Tan Sheep"brand and has made remarkable achievements.In order to explore the resource efficiency and quality of Tan sheep industry,the current situations and advantages of brand development,this paper made an empirical research through field investigations.The research was mainly concentrated on breeding scale,industrial integration,brand building,breeding benefits,and policy support.After a comprehensive evaluation,it came up with the recommendation that the Tan sheep industry should take the high-quality,high-end and green development road.

Solvent Effects on Preparation of Pd-Based Catalysts: Influence on Properties of Palladium and Its Catalytic Activity for Benzyl Alcohol Oxidation

Solvent effects are important for the solution preparation of nanoscale metal materials, in which the sizes and properties of the nanomaterials are greatly influenced by the solvents. In this study, a series of Pd/XC-72 catalysts were synthesized by a facile solvothermal method in solvents with different numbers of hydroxyl groups, including ethanol, ethylene glycol, and glycerine. The as-prepared catalysts Pd/XC-72(EA), Pd/XC-72(EG) and Pd/XC-72(GI) were characterized by XRD, TEM, TGA, ICP-MS and multipoint nitrogen adsorption-desorption experiments. It was found that Pd/XC-72(GI) had the highest metallic dispersion and the smallest particle size (4.9 nm). Furthermore, Pd/XC-72(GI) exhibited the best catalytic performance for solvent-free selective oxidation of benzyl alcohol while the catalytic activities of Pd/XC-72 catalysts decreased in the order: Pd/XC-72(GI) > Pd/XC-72(EG) > Pd/XC-72(EA).

Intrinsic magnetic topological materials

Topological states of matter possess bulk electronic structures categorized by topological invariants and edge/surface states due to the bulk-boundary correspondence. Topological materials hold great potential in the development of dissipationless spintronics, information storage and quantum computation, particularly if combined with magnetic order intrinsically or extrinsically. Here, we review the recent progress in the exploration of intrinsic magnetic topological materials, including but not limited to magnetic topological insulators, magnetic topological metals, and magnetic Weyl semimetals. We pay special attention to their characteristic band features such as the gap of topological surface state, gapped Dirac cone induced by magnetization (either bulk or surface), Weyl nodal point/line and Fermi arc, as well as the exotic transport responses resulting from such band features. We conclude with a brief envision for experimental explorations of new physics or effects by incorporating other orders in intrinsic magnetic topological materials.

Magnetic beads-based multicolor colorimetric immunoassay for ultrasensitive detection of aflatoxin B_(1)

Aflatoxin B_(1)(AFB_(1))is one of the most toxic,mutagenic and carcinogenic mycotoxin,widely exists in contaminated food,grains and feedstuff products.In this study,a novel magnetic beads multicolor colorimetric immunoassay(MBMCIA)based on Au@Ag nanorods(Au@Ag NRs)is proposed to visual detect ultralow concentration of AFB_(1)with high-resolution by the naked-eye.To design the MBMCIA system,AFB_(1)-BSA conjugates were first coated on the surface of magnetic beads(MBs),then alkaline phosphatase(ALP)as a bridge between immunoassay a nd color reaction was used for catalytic hydrolysis of ascorbic acid-phosphate to generate reductive ascorbic acid.Finally,the yielded ascorbic acid could reduce silver ions to grow a silver coating on the surface of gold nanorods to generate Au@Ag NRs,which leads to the bule-shifted longitudinal absorption peak of Au NRs,accompanying with a series of perceptible color change.Under the optimal conditions,the proposed MBMCIA exhibited go od sensitivity and specificity for the detection of AFB_(1)with the detection limit as low as 5.7 pg/mL Meanwhile,the MBMCIA was also applied for the analysis of AFB_(1)in spiked wheat samples,the obtained recoveries range from 99.1%to 104.3%with relative standard deviation(RSD)less than 7.05%were acceptable.The proposed MBMCIA integrates separated,enriched,anti-interfe rence and signal read-out into one,which opens up a new avenue for an on-site visual food safety inspection or environmental monitoring.

Integrated river basin management in rapidly urbanizing areas:a case of Shenzhen,China

The rapid urbanization of China is causing a burden on their water resources and hindering their sustainable development.This paper analyzes effective methods to integrated river basin management(IRBM)using Longgang River basin of Shenzhen as an example,which is the city with the fastest rate of urbanization in China and even the whole world.Over the past 20 years,China has undergone a population boom due to the increase of immigrant workers and rapid development of laborintensive industries,which led to the sharp increase of water consumption and sewage discharge.However,the construction of the water infrastructure is still lagging far behind the environmental and social development,with only 32.7%of sewage in the district being treated.Currently,every water quality indicator of the Longgang River basin was unable to meet the required corresponding environmental standards,which further aggravated the water shortages of the region.Thus,an analytical framework is proposed to address the IRBM of the study area.The problems with the current management system include the lack of decentralization in decision-making,lack of enforcement with redundant plans,weak management capacity,financial inadequacy,and a poor system of stakeholder participation.In light of the principles of IRBM and the situation of the region,corresponding measures are put forward,including an increase of power given to sub-district offices,fewer but more feasible plans,capacity building among stakeholders,a combination of planning and marketing for overcoming financial inadequacy,and profound reform in the public participation system.The framework and institutional suggestions could inform similar processes in other representative river basins.

Spherical to truncated octahedral shape transformation of palladium nanocrystals driven by e-beam in aqueous solution

The crystallographic shapes of nano crystals play critical roles in determi ning their physical and chemical properties.Liquid phase synthesis serves as one of the most importa nt approaches for preparing shape-controlled nano crystals,therefore,understa nding the formation mecha nisms of the thermod yn amic equilibrium structures of nano crystals in liquid soluti on is importa nt.Using in situ liquid cell tran smissi on electron microscopy(TEM),we observe for the first time the shape transformation of individual palladium nanocrystals from energy unfavored spherical shapes into equilibrium truncated octahedrons in aqueous solution.Via quantitative analysis of the shape evolution dynamics of an individual Pd nano crystal,we find that about 10%of nano crystal atoms were relocated during the shape tran sformation.The mass tran sport is attributed to the synergetic effect of electron beam irradiation and water environment.

Scrutinizing the facile growth of β-Ag_(2)Se fine films

Silver selenide thin film is one of the best candidates for thermoelectric devices.In the previous report,we demonstrated that high-performanced[201]orientedβ-Ag_(2)Se thin films can be prepared by direct metal surface element reaction(DMSER)solution selenization in a really short time at room temperature.However,the underlying mechanism of the fast reaction process were not discussed in depth.Herein,based on hard soft acid base(HASB)theory and strong oxidation,we further explored the possible reaction mechanism of the in-situ growth ofβ-Ag_(2)Se thin films as the function of the reaction time.The time-dependent experimental results showed that the formation of theβ-Ag_(2)Se on elemental Ag precursor(∼690nm thick)in Se/Na_(2)S precursor solution is in a growth driven mode with no obvious orientation or growth rate selections to the elemental Ag precursors.Our investigations provide a prerequisite for the further preparation of thermoelectric materials with excellent properties.

基于细胞仿生矿化合成纳米材料及其应用

近年来,随着纳米科学技术的发展,纳米材料的"绿色合成方法"研究显得愈发重要。基于细胞活体及其分泌物模拟生物矿化合成纳米材料已成为绿色合成纳米材料的研究前沿。该方法具有操作简单、安全经济和环境友好等优点,合成得到的纳米材料具有良好的分散性、稳定性和特殊的性能。该方法得到的纳米材料已在化学、材料学、生物医学等领域展现出了广泛的应用前景,引起了人们的极大关注。本文综述了应用细菌、真菌、植物及人体细胞等活体细胞或分泌物仿生矿化合成各种形貌及不同尺寸的无机纳米结构材料的研究进展;着重评述了纳米材料的仿生矿化合成方法、合成机制以及应用研究现状与前景,并对纳米材料基于细胞合成技术的发展趋势进行了展望。

部分国家跨境服务增值税政策研究

随着跨境服务贸易的迅猛发展,对跨境服务的增值税重复征税和非故意双重不征税问题日益凸显,完善相关增值税制度是很多国家亟需解决的问题。本文在借鉴OECD关于跨境服务增值税政策的最新研究成果及部分国家实践的基础上,提出对完善我国跨境服务贸易增值税政策的建议。

Ligand-mediated contaminant degradation by bare and carboxymethyl cellulose-coated bimetallic palladium-zero valent iron nanoparticles in high salinity environments

The application of nanoscale zero-valent iron(nZVI) for the degradation of contaminants has been extensively investigated, however, few studies have focused on degradation in high salinity environments. In this study, the ability of bare and carboxymethyl cellulose(CMC)-coated bimetallic Pd-nZVI particles to degrade 33′44′-tetrachlorobiphenyl in high saline water(SW) is examined with particular attention given to the effects of ethylenediaminetetraacetic acid(EDTA) on the rate of degradation. EDTA enhances the reactivity of Pd-nZVI in SW, with evidence provided to link this to the removal of the passivating layer. Additionally, a conceptual model is proposed which provides a quantitative description of the removal of these iron oxide layers in the presence of EDTA. An optimum EDTA to bare Pd-nZVI molar ratio of 0.1 exists, with insufficient EDTA unable to remove the passivating layer whilst excess EDTA results in Fe loss and enhanced agglomeration due to magnetic attraction of the bare Fe(0) particles. In contrast, CMCcoating of Pd-nZVI assemblages actually impedes degradation, despite the coated particles displaying a smaller average size compared to uncoated particles, with even the presence of EDTA in this case not significantly improving degradation. The reduced reactivity in the presence of CMC is primarily attributed to the effect of CMC on the association of Pd with nZVI particles. In particular, the presence of CMC reduced the total amount of Pd incorporated with the stabilized particles compared to the non-stabilized particles.Additionally, the presence of CMC results in less Pd present in its reactive zero-valent oxidation state.

氧空位超薄Co2AlO4纳米片的合成及其增强电催化氧析出反应（英文）

本文报道了通过脱合金和后续退火工艺合成一种新型超薄二维尖晶石结构的Co2Al O4纳米片.通过温和的溶剂热还原法将氧空位缺陷引入Co2Al O4纳米片中,使得电化学表面积增大,活性位密度变高,钴原子得到电子而产生更多的空轨道.这些空轨道有利于接受水分子中氧原子的孤对电子,促进水分子的活化.含有氧空位的超薄Co2Al O4纳米片在10 m A cm^-2时的过电位为280 m V,塔菲尔斜率为70.98 m V dec^-1.此外,其在碱性溶液中也表现出显著的稳定性,并且优于多数已报道的Co3O4电催化剂.该工作为制备高效的可持续新能源材料提供了新思路.

基于服务贸易统计制度的跨境服务增值税政策研究

从服务贸易统计制度来看,服务进出口统计遵循"属人"原则,而增值税的消费地属性决定了其"属地"原则。因此,服务的出口和进口并不必然对应增值税退税和征税。本文基于《国际服务贸易统计手册》等服务贸易统计制度的视角,重新评析增值税消费地原则在服务贸易进出口中的适用范围。建议根据服务贸易进出口的具体模式,分别明确B2B、B2C服务贸易的增值税政策,在此基础上合理界定跨境服务出口零税率范围,并逐步加强跨境服务进口税收征管。

Iridium complex of porphycene:a new member of metalloporphycene

Iridium(Ⅲ)porphycene complex was synthesized and structurally characterized for the first time.The introduction of the posttransition iridium(Ⅲ)ion not only significantly enhances the absorption intensity at the end of visible region,but also displays efficient singlet oxygen quantum yield(76%),which is applicable for photodynamic therapy in living cells.

Highly-efficient photosensitizer based on AIEgen-decorated porphyrin for protein photocleaving

An AIEgen decorated porphyrin(TPETPyP)was easily obtained through a one-step reaction.The bulky TPE in TPETPyP greatly impeded the intermolecularπ-πstacking of the porphyrin core,which significantly suppressed aggregation-caused quenching(ACQ)effect of TPETPyP in aqueous solution.The four pyridinium salts formed in TPETPyP also render the whole molecule water solubility,which eliminated its aggregation.TPETPyP exhibited 1O2 quantum yield as high as 0.85 in PBS.Moreover,it also showed high binding affinity to proteins,the major biotarget of 1O2.The high 1O2 quantum yield plus the great binding ability of TPETPyP toward proteins makes it a highly-efficient protein photocleaving agent.Protein electrophoresis experiments demonstrated that TPETPyP can photocleave BSA upon visible light irradiation,indicating that TPETPyP can act as a promising photosensitizer(PS)in PDT.The work here will provide a facile strategy to utilize AIEgens modified traditional PSs for photodynamic therapy(PDT).

Bandgap opening in MoTe2 thin flakes induced by surface oxidation

Recently,the layered transition metal dichalcogenide 1T′-MoTe2 has generated considerable interest due to their superconducting and non-trivial topological properties.Here,we present a systematic study on 1T′-MoTe2 single-crystal and exfoliated thin-flakes by means of electrical transport,scanning tunnelling microscope(STM)measurements and band structure calculations.For a bulk sample,it exhibits large magneto-resistance(MR)and Shubnikov–de Hass oscillations inρxx and a series of Hall plateaus inρxy at low temperatures.Meanwhile,the MoTe2 thin films were intensively investigated with thickness dependence.For samples,without encapsulation,an apparent transition from the intrinsic metallic to insulating state is observed by reducing thickness.In such thin films,we also observed a suppression of the MR and weak anti-localization(WAL)effects.We attributed these effects to disorders originated from the extrinsic surface chemical reaction,which is consistent with the density functional theory(DFT)calculations and in-situ STM results.In contrast to samples without encapsulated protection,we discovered an interesting superconducting transition for those samples with hexagonal Boron Nitride(h-BN)film protection.Our results indicate that the metallic or superconducting behavior is its intrinsic state,and the insulating behavior is likely caused by surface oxidation in few layer 1T’-MoTe2 flakes.

Biomimetic Au nanodot synthesis using Escherichia coli secretion and interaction with α-ketoglutaric acid

Dear Editor,Gold nanostructures have distinctive physicochemical properties,such as quantum size effects,surface plasmon resonance(SPR),high catalytic activity,and self-assembly,so they are one of the most widely studied materials.Over the past few years,researchers have increasingly focused on a diverse range of biomedical applications of gold nanoparticles(AuNPs)for photothermal and targeted drug delivery treatment for cancer and as biodiagnostic probes(Rao and Cheetham,2001).However,conventional AuNP chemosynthesis involves hazardous chemicals and has a high cost.In addition,a lack of excellent monodispersion,water dispersibility,and biocompatibility limit applications in biology and medicine(Kumar et al.,2008).Therefore,a green chemistry strategy for fabricating eco-friendly,nontoxic,cost-effective AuNPs with good biocompatibility and functionality is required.