In situ Hydrothermal Oxidation of Ternary FeCoNi Alloy Electrode for Overall Water Splitting

Exploring noble metal-free catalyst materials for high efficient electrochemical water splitting to produce hydrogen is strongly desired for renewable energy development.In this article,a novel bifunctional catalytic electrode of insitu-grown type for alkaline water splitting based on FeCoNi alloy substrate has been successfully prepared via a facile one-step hydrothermal oxidation route in an alkaline hydrogen peroxide medium.It shows that the matrix alloy with the atom ratio 4∶3∶3 of Fe∶Co∶Ni can obtain the best catalytic performance when hydrothermally treated at 180℃for 18 h in the solution containing 1.8 M hydrogen peroxide and 3.6 M sodium hydroxide.The as-prepared Fe_(0.4)Co_(0.3)Ni_(0.3)-1.8 electrode exhibits small overpotentials of only 184 and 175 mV at electrolysis current density of 10 mA cm^(-2)for alkaline OER and HER processes,respectively.The overall water splitting at electrolysis current density of 10 mA cm^(-2)can be stably delivered at a low cell voltage of 1.62 V.These characteristics including the large specific surface area,the high surface nickel content,the abundant catalyst species,the balanced distribution between bivalent and trivalent metal ions,and the strong binding of in-situ naturally growed catalytic layer to matrix are responsible for the prominent catalytic performance of the Fe_(0.4)Co_(0.3)Ni_(0.3)-1.8 electrode,which can act as a possible replacement for expensive noble metal-based materials.

Oxygen migration triggering molybdenum exposure in oxygen vacancy-rich ultra-thin Bi_(2)MoO_(6) nanoflakes: Dual binding sites governing selective CO_(2) reduction into liquid hydrocarbons

Oxygen vacancy plays vital roles in regulating the electronic and charge distribution of the oxygen deficient materials.Herein,abundant oxygen vacancies are created during assembling the two-dimensional(2D)ultra-thin Bi_(2)MoO_(6) nanoflakes into three dimensional(3D)Bi_(2)MoO_(6) nanospheres,resulting in significantly improved performance for photocatalytical conversion of CO_(2) into liquid hydrocarbons.The increased performance is contributed by two primary sites,namely the abundant oxygen vacancy and the exposed molybdenum(Mo)atom induced by oxygen-migration,as revealed by the theoretical calculation.The oxygen vacancy(Ov)and uncovered Mo atom serving as dual binding sites for trapping CO_(2) molecules render the synchronous fixation-reduction process,resulting in the decline of activation energy for CO_(2) reduction from 2.15 eV on bulk Bi_(2)MoO_(6) to 1.42 eV on Ov-rich Bi_(2)MoO_(6).Such a striking decrease in the activation energy induces the efficient selective generation of liquid hydrocarbons,especially the methanol(C_(2)H_(5) OH)and ethanol(CH_(3) OH).The yields of CH_(3) OH and C_(2)H_(5) OH over the optimal Ov-Bi_(2)MoO_(6) is high up to 106.5 and 10.3μmol g^(-1) respectively,greatly outperforming that on the Bulk-Bi_(2)MoO_(6).

Co_(2)P nanorods with exposure of high-index facets for efficient photochemical reduction of CO_(2)by promoting the directional transfer of electrons

Herein,Co_(2)P nanorods(NRs)with exposure to high-index facets(HIFs)were prepared by a special assembly-calcination method using thioacetamide(TAA)as a structure-directing reagent.The analysis of adsorption energies of S atoms on different facets as well as the surface energies of Co_(2)P indicate that the HIFs become more stable after adsorbing S atoms.With rich unsaturated sites on HIFs,the photochemical reduction rate of CO_(2)over Co_(2)P NRs is 14.5 mmol h^(-1)g^(-1)for the production of CO within 3 h.The analysis of electron transfer,bond lengths,bond angles and adsorption energies indicate that the CO_(2)molecules are more easily adsorbed and activated on the HIFs.The free energy calculations and d band theory demonstrate that the HIFs are conducive to reducing the formation energy barriers as well as improving the stability of the intermediate^(*)COOH,then enhancing the catalytic performance of CO_(2)reduction.

MoO_(x) nanoclusters on Mo-doped TiO_(2) nanosheets with enhanced singlet oxygen generation and sulfide conversion abilities for photocatalytic aerobic oxidative desulfurization

Photocatalytic aerobic oxidation desulfurization(PAODS)is a promising and sustainable alternative to conventional,energyintensive desulfurization techniques for petroleum products.However,its development is greatly plagued by the low capability in generating highly reactive oxygen species and sluggish kinetics of sulfide oxidation of reported photocatalysts.Here we report a class of MoO_(x)nanocluster decorated on ultrathin Mo-doped TiO_(2)nanosheet(MoO_(x)/MoTiO)catalyst for efficiently facilitating the photocatalytic aerobic oxidation of sulfides.We demonstrate that MoO_(x)/MoTiO can not only promote the generation of highly reactive singlet oxygen(^(1)O_(2))but also enhance the aerobic conversion of sulfides,which leads to a record dibenzothiophene oxidation activity of 3.90 mmol g^(-1)h^(-1).The multiple experimental characterizations and density functional theory calculations collectively reveal that the doped-Mo sites can interact with the photogenerated excitons,enabling directly energy transfer generation of^(1)O_(2)through a new exciton modulation mechanism,and the coordination unsaturated MoO_(x)clusters play the role of co-catalyst to enhance the separation of charge carriers,and effectively catalyze the reaction between sulfides and1O_(2)to form sulfones.

A lightweight and high compressive resistance thermal insulation material with dual-network structure

Ceramic fibrous aerogels are highly desirable for thermal management materials due to their high porosity,excellent elasticity,thermal conductivity,and good thermal resistance.However,the fabrication of nanofibrous aerogel with super-elasticity and good shape retention at the same time has remained challenging.To meet the requirements,a novel anisotropy nanofibrous-granular aerogel with a quasi-layered multi-arch-like and hierarchical-cellular structure is designed and prepared by vacuum-filtration-assisted freeze-drying and sintering.The quasi-layered multi-arch and flexible nanofibers endowed the aerogels with excellent mechanical robustness(ultimate stress up to 60 kPa with strain 60%)and super-elasticity with recoverable compression strain up to 60%.The introduced SiO_(2) aerogel nanoparticles and nanofibers are assembled into an arch-like structure and become the connection point of adjacent nanofibers,which endows low thermal conductivity(0.024 mW/(m·K))of composite aerogel.This novel strategy provides a fresh perspective for the preparation of nanofibrous aerogel with robust mechanical in thermal insulation and other fields.

Top priority current path between SiC particles during ultra-high temperature flash sintering: Presence of PyC “bridges”

Flash sintering(FS)is a novel technique for rapidly densifying silicon carbide(SiC)ceramics.This work achieved a rapid sintering of SiC ceramics by the utilization of ultra-high temperature flash sintering within 60 s.Pyrolysis carbon(PyC)“bridges”were constructed between SiC particles through the carbonisation of phenolic resin,providing a large number of current channels.The incubation time of the flash sintering process was significantly reduced,and the sintering difference between the centre and the edge regions of the ceramics was minimized,with an average particle size of the centre region and edge region being 12.31 and 9.02μm,respectively.The results showed that the porosity of the SiC ceramics after the flash sintering was reduced to 14.79% with PyC“bridges”introduced,and the Vickers hardness reached 19.62 GPa.PyC“bridges”gradually evolved from amorphous eddy current carbon to oriented graphite carbon,indicating that the ultra-high temperature environment in which the sample was located during the flash sintering was successfully constructed.Ultra-high temperature flash sintering of SiC is expected to be applied to the local repair of matrix damage in SiC ceramic matrix composites.

产业政策如何影响企业规模分布——基于资源配置视角的实证分析

产业政策对经济运行的影响机制历来存在较大争议。本文利用1998-2007年中国规模以上工业企业数据库和各省份政府五年规划的匹配数据,从微观企业资源配置视角考察产业政策影响企业规模分布的作用机制。研究发现:(1)在中国微观企业普遍存在资本投入不足与劳动投入过度的背景下,产业政策的实施缓解了企业的资本投入不足,同时抑制了劳动投入过度。政府补贴、税收优惠和信贷支持三类产业政策都显著抑制了企业劳动要素投入过度的扭曲,但税收优惠并未缓解企业资本投入不足的扭曲。(2)产业政策的实施通过资源配置渠道总体上促进了企业的规模提升,其中对大企业规模提升作用更为显著。产业政策实施带来的竞争效应,会淘汰部分小企业,但这一效应居次要地位。本文的研究对于理解产业政策经济影响的作用机制提供了新视角。

非洲猪瘟病毒的生物学特性与疫苗研制的难点

非洲猪瘟(African swine fever,ASF)是由非洲猪瘟病毒(African swine fever virus,ASFV)引起的一种猪烈性传染病,是全球养猪业的"头号杀手",强毒株引发的超急性和急性感染死率高达100%。2018年8月ASF首次传入我国,截止2019年6月6日,已有32个省份累计暴发137起疫情,给我国社会、经济构成巨大威胁。ASF疫苗的研制始于20世纪60年代,但均以失败而告终,其主要原因是对ASFV生物学特性缺乏深入的研究。有效控制当前ASF疫情扩散、研制安全有效的疫苗将是我国面临的巨大挑战。本文对ASFV形态与基本结构、传播途径、致病机制、基因组及编码蛋白、入侵机制、免疫逃逸等生物学特性进行了概述,并分析了当前疫苗研制面临的难点,以期为我国有效控制ASF疫情及病原研究提供参考。

Effect of Tangnaikang on TGF-β_1-induced transdifferentiation of human renal tubular epithelial HK-2 cells

OBJECTIVE： To explore the function of Tangnai- kang （TNK） in the prevention and treatment of re- nal interstitial fibrosis through transdifferentiation of the human renal tubular epithelial cell line HK-2 induced bytransforming growth factor-β1 （TGF-β1）. METHODS： HK-2 cells cultured in dulbecco＇s modi- fied eagle medium/F12 （1：1） with 10% fetal calf se- rum were divided into six groups： blank control group, TGF-β1 group （TGF-β1 10 ng/mL）, serum con- trol group （TGF-β1 10 ng/mL ＋ 10% serum）, treat- ment group 1 （TGF-β1 10 ng/mL ＋ 5% TNK serum）, treatment group 2 （TGF-β1 10 ng/mL＋10% TNK se-rum）, and treatment group 3 （TGF-β1 10 ng/mL＋ 20% TNK serum）. Cell proliferation was detected by 4,5-Dimethylthiazol-2-yl）-2,5-diphenyltetrazoliu m bromide assay. Expression of a-smooth muscle ac- tin （a-SMA） and E-cadherin were observed by im- munohistochemical assay. The contents of collagen Ⅰ （Col Ⅰ）, collagen Ⅲ（ColⅢ）, and fibronectin （FN） in the culture medium supernatant were detected by ELISA. RESULTS： E-cadherin was expressed and α-SMA was not expressed in normal HK-2 cells. In HK-2 cells cultured with TGF-β1, α-SMA expression signifi- cantly increased, HK-2 cells significantly proliferat- ed, and secretion of Col Ⅰ, Col Ⅲ, and FN significantly increased compared with the blank control group （all P〈0.05）. In the HK-2 cells cultured with TGF-β1 and TNK serum, the expression of α-SMA signifi- cantly decreased, the expression of E-cadherin sig- nificantly increased, and the cell proliferation and the secretion of Col Ⅰ, Col Ⅲ and FN were significant- ly inhibited compared with the TGF-β1 group （all P〈 0.05. CONCLUSION： TNK can inhibit cell proliferation and reduce secretion of Col Ⅰ, Col Ⅲ, and FN.This in- dicates that TNK can inhibit transdifferentiation of human renal tubular epithelial cells induced by TGF-β1, with the effect of preventing and treating renal interstitial fibrosis.

THz trapped ion model and THz spectroscopy detection of potassium channels

Advanced molecular dynamics(MD)simulation and infrared(IR)spectroscopy have been widely adopted to reveal the detailed dynamic process of high-speed selective permeability of potassium channels.Yet these MD simulations cannot avoid the choice of empirical molecular force fields and high transmembrane voltages(as driving electric fields for ions)far exceeding physiological levels.Moreover,the IR spectroscopy method usually requires isotope labels for carbonyl groups of the channels,which may change the original permeation process.Here,we build the terahertz(THz)trapped ion model for the selectivity filter(SF)of potassium channels KcsA based on the density functional theory(DFT)calculation of ion potentials.In this model,the zero-point energy of trapped ions and quantum tunneling effect provide the physical basis for near diffusion limited permeation rates of ions and explain the high driving electric field in MD simulations.Quantitative calculations of zero-point energy and tunneling probability show that the quantum effect assisted knock-on mechanism may help to realize the physiological functions of potassium channels.Furthermore,based on the trapped ion model,we calculated the ion decoherence timescale under the influence of protein environmental noise.We use the quantum optics method to describe the interaction between THz waves and the trapped ion.Then the novel THz spectroscopy approaches through the THz resonance fluorescence and the intense field non-resonant effect are presented theoretically.These are expected to be isotope label-free detective methods of the rapid ion permeation dynamics.

High-throughput model-building and screening of zeolitic imidazolate frameworks for CO2 capture from flue gas

To find potential zeolitic imidazolate frameworks(ZIFs)for CO2 capture from flue gas,we built 169,898 ZIF models from 84,949 hypothetical zeolite networks.By calculating their lattice energies,accessible volumes to CO2,the isosteric adsorption heat(Qst)of H2 O,Henry’s constant ratio(SKH)of CO2/N2,percent regenerability(R%),CO2 working capacity(ΔNCO2),CO2/N2 adsorption selectivity(SCO2/N2))and adsorbent performance score(APS),we identi fied 49 hydrophobic ZIF structures that might outplay already-realised ZIFs built from the same imidazolate linkers for CO2 capture from flue gas.

Stress-induced phase transformation and phase boundary sliding in Ti: An atomically resolved in-situ analysis

In-situ tensile experiments on pure Ti were performed in a transmission electron microscope at room temperature.The dynamic process of stress-induced hexagonal closed-packed(hcp)to face-centered cu-bic(fcc)structural transformation ahead of a crack tip was captured at the atomic level.Intriguingly,a sliding behavior of the ensuing(0001)hcp/(1¯11)_(fcc) phase boundary was observed to further accommodate the plastic deformation until crack initiation.The sliding was accomplished via the successive conserva-tive glide of extended dislocations along the(0001)hcp/(1¯11)_(fcc) phase boundary.A molecular dynamics simulation was carried out to corroborate the experiments and the results confirm the new dislocation-mediated sliding mechanism.

Advanced municipal wastewater treatment and simultaneous energy/resource recovery via photo(electro)catalysis

Wastewater management and energy/resource recycling have been extensively investigated via photo(electro)catalysis.Although both operation processes are driven effectively by the same interfacial charge,each system is practiced separately since they require very different reaction conditions.In this review,we showcase the recent advancements in photo(electro)catalytic process that enables the wastewater treatment and simultaneous energy/resource recovery(WT-ERR).Various literatures based on photo(electro)catalysis for wastewater treatment coupled with CO_(2)conversion,H_(2)production and heavy metal recovery are summarized.Besides,the fundamentals of photo(electro)catalysis and the influencing factors in such synergistic process are also presented.The essential feature of the catalysis lies in effectively utilizing hole oxidation for pollutant degradation and electron reduction for energy/resource recovery.Although in its infancy,the reviewed technology provides new avenue for developing next-generation wastewater treatment process.Moreover,we expect that this review can stimulate intensive researches to rationally design photo(electro)catalytic systems for environmental remediation accompanied with energy and resource recovery.

Molecular simulations of host-guest interactions between zeolite framework STW and its organic structure-directing agents

Zeolites have been widely applied in many chemical processes owing to their featured microporous framework structures.Organic structure-directing agents(OSDAs) play an important role during of the formation of zeolite frameworks via non-bonding host-guest interactions.Understanding these interactions is crucial to the design of OSDAs and the synthesis of target zeolites.Here,we report a molecular simulation study in the host-guest interactions between zeolite framework STW and 21 alkylated imidazolium and pyrazolium cations that have been used as the OSDAs for the synthesis of STW-type zeolites.We find that OSDAs that have successfully directed the formation of STW exhibit stronger host-guest interactions than unsuccessful ones.Furthermore,we find all successful OSDAs possess relatively more negative atomic charges on nitrogen atoms and smaller dipole moments.According to this finding,we have designed seven new alkylated imidazolium and pyrazolium cations that may be suitable for zeolite STW,and verified their structure-directing capability by molecular simulation calculations.

Lipid lowering effects and safety of evolocumab in Chinese patients at very high cardiovascular risk:a single-center study

Low-density lipoprotein cholesterol(LDL-C)is an independent risk factor for atherosclerotic cardiovascular disease(ASCVD).Even after lipid-lowering therapy(LLT)with statins or statin–ezetimibe,a large proportion of patients at very high risk still do not reach the LDL-C targets(<1.4 mmol/L and≥50%reduction).[1,2]Proprotein convertase subtilisin/kexin type 9 inhibitor(PCSK9i)is recommended for patients at high or very high cardiovascular risk inwhom LDL-C reduction is not adequate with statin therapy or in those with statin intolerance.Limited data are available regarding the use of PCSK9i in China.

A high-isolation coupled-fed building block for metal-rimmed 5G smartphones

A dual-antenna building block with high isolation is presented for metal-rimmed fifth-generation(5G)smartphones.A coupled-fed loop antenna and a coupledfed slot antenna based on a simple T-slot etched on the ground plane are meticulously designed to form a compact building block.