A high-entropy-designed cathode with V^(5+)-V^(2+) multi-redox for high energy density sodium-ion batteries

Na_(3)V_(2)(PO_(4))_(3)(NVP)is gifted with fast Na^(+)conductive NASICON structure.But it still suffers from low electronic conductivity and inadequate energy density.Herein,a high-entropy modification strategy is realized by doping V^(3+)site with Ga^(3+)/Cr^(3+)/Al^(3+)/Fe^(3+)/In^(3+)simultaneously(i.e.Na_(3)V_(2-x)(GaCrAlFeIn)_x(PO_(4))_(3);x=0,0.04,0.06,and 0.08)to stimulate the V^(5+)■V^(2+)reversible multi-electron redox.Such configuration high-entropy can effectively suppress the structural collapse,enhance the redox reversibility in high working voltage(4.0 V),and optimize the electronic induced effect.The in-situ X-ray powder diffraction and in-situ electrochemical impedance spectroscopy tests efficaciously confirm the robust structu ral recovery and far lower polarization throughout an entire charge-discharge cycle during 1.6-4.3 V,respectively.Moreover,the density functional theory calculations clarify the stronger metallicity of high-entropy electrode than the bare that is derived from the more mobile free electrons surrounding the vicinity of Fermi level.By grace of high-entropy design and multi-electron transfer reactions,the optimal Na_(3)V_(1.7)(GaCrAlFeIn)_(0.06)(PO_(4))_(3)can exhibit perfect cycling/rate performances(90.97%@5000 cycles@30 C;112 mA h g^(-1)@10 C and 109 mA h g^(-1)@30 C,2.0-4.3 V).Furthermore,it can supply ultra-high185 mA h g^(-1)capacity with fa ntastic energy density(522 W h kg^(-1))in half-cells(1.4-4.3 V),and competitive capacity(121 mA h g^(-1))as well as energy density(402 W h kg^(-1))in full-cells(1.6-4.1 V),demonstrating enormous application potential for sodium-ion batteries.

PPP项目失败的组态研究——基于30个案例的清晰集定性比较分析

相较于计划经济时期的“命令-控制”模式和转型时期的“委托-代理”模式,以PPP为代表的公私部门合作“契约模式”是新时代一种新型的公共治理模式,然而由于存在不同层次、不同角度的问题,PPP项目在实施过程中容易出现“1+1<2”的失败情况。论文以30个典型PPP项目失败案例为研究对象,采用定性比较分析方法对PPP项目失败的类型及其前因条件的交互作用进行实证检验,结果显示PPP项目失败存在七类主要组态模式,并且各个组态构型呈现出非均匀分布,特别是由于我国是一个发展中国家,PPP失败中的政策法律层面的制度试错风险较高。论文丰富发展了PPP项目的相关理论,并对如何应对PPP项目失败提出了相应的建议和措施。

Structure and cavitation erosion behavior of HVOF sprayed multi-dimensional WC-10Co4Cr coating

A new kind of multi-dimensional WC-10Co4Cr coating which is composed of nano,submicron,micron WC grains and CoCr alloy,was developed by high velocity oxy-fuel(HVOF)spraying.Porosity,microhardness,fracture toughness and cavitation erosion resistance of the multi-dimensional coating were investigated in comparison with the bimodal and nanostructured WC?10Co4Cr coatings.Moreover,the cavitation erosion behavior and mechanism of the multi-dimensional coating were explored.Results show that HVOF sprayed multi-dimensional WC-10Co4Cr coating possesses low porosity(≤0.32%)and high fracture toughness without obvious nano WC decarburization during spraying.Furthermore,it is discovered that the multi-dimensional WC-10Co4Cr coating exhibits the best cavitation erosion resistance which is enhanced by approximately 28%and 34%,respectively,compared with the nanostructured and bimodal coatings in fresh water.The superior cavitation resistance of multi-dimensional WC-10Co4Cr coating may originate from the unique micro?nano structure and excellent properties,which can effectively obstruct the formation and propagation of cavitation erosion cracks.

Near-Real-Time Carbon Emission Accounting Technology Toward Carbon Neutrality

Climate change is the greatest environmental threat to humans and the planet in the 21st century.Global anthropogenic greenhouse gas emissions are one of the main causes of the increasing number of extreme climate events.Cumulative carbon dioxide(CO_(2))emissions showed a linear relationship with cumulative temperature rise since the pre-industrial stage,and this accounts for approximately 80%of the total anthropogenic greenhouse gases.Therefore,accurate and reliable carbon emission data are the foundation and scientific basis for most emission reduction policymaking and target setting.Currently,China has made clear the ambitious goal of achieving the peak of carbon emissions by 2030 and achieving carbon neutrality by 2060.The development of a finer-grained spatiotemporal carbon emission database is urgently needed to achieve more accurate carbon emission monitoring for continuous implementation and the iterative improvement of emission reduction policies.Near-real-time carbon emission monitoring is not only a major national demand but also a scientific question at the frontier of this discipline.This article reviews existing annual-based carbon accounting methods,with a focus on the newly developed real-time carbon emission technology and its current application trends.We also present a framework for the latest near-real-time carbon emission accounting technology that can be widely used.The development of relevant data and methods will provide strong database support to the policymaking for China’s“carbon neutrality”strategy.Finally,this article provides an outlook on the future of real-time carbon emission monitoring technology.

Structure elucidation,immunomodulatory activity,antitumor activity and its molecular mechanism of a novel polysaccharide from Boletus reticulatus Schaeff

A new water-soluble heteropolysaccharide with a molecular weight of 15 k Da was isolated from the fruiting bodies of Boletus reticulatus Schaeff.Structural characterization results revealed that B.reticulatus Schaeff polysaccharide(BRS-X)had a backbone of 1,6-linkedα-D-galactose and 1,2,6-linkedα-D-galactose which branches were mainly composed of a terminal 4-linkedβ-D-glucose and the ratio of D-galactose and D-glucose was 5:1.Bioactivity assays indicated that BRS-X displayed a strong proliferative activity in T cells and B cells and promoted the secretion of immunoglobulin G(Ig G),Ig E,Ig D and Ig M.In addition,BRS-X could facilitate the proliferation and phagocytosis of RAW264.7 cells and could significantly inhibit the growth of tumors in S180-bearing mice.The results of transcriptome sequencing analysis illustrated that total 46 genes enriched in MAPK and total 34 genes enriched in PI3 K/Akt signaling pathways in BRS-X group.The protein VEGF and VEGFR expression were significantly reduced under the treatment with BRS-X.These findings provide a scientific basis for the edible and medicinal value of BRS-X.

Effect of Jianweiyuyang granule on gastric ulcer recurrence and expression of VEGF mRNA in the healing process of gastric ulcer in rats

AIM: To investigate the effect of Jianweiyuyang (JWYY)granule on gastric ulcer recurrence and its mechanism in the treatment of gastric ulcer in rats.METHODS: Gastric ulcer in rats was induced according to Okeba's method with minor modification and the recurrence model was induced by IL-1β. The expression of vascular endothelial growth factor mRNA (VEGF mRNA) was examined by reverse transcription polymerase chain reaction in gastric ulcer and microvessel density (MVD) adjacent to the ulcer margin was examined by immunohistochemistry.RESULTS: MVD was higher in the JWYY treatment group (14.0±2.62) compared with the normal, model and ranitidine treatment groups (2.2±0.84, 8.8±0.97, 10.4±0.97) in rats (P＜0.01). The expression level of VEGF mRNA in gastric tissues during the healing process of JWYY treatment group rats significantly increased compared with other groups (normal group: 0.190±0.019, model group: 0.642±0.034,ranitidine group: 0.790±0.037, P＜0.01).CONCLUSION: JWYY granules can stimulate angiogenesis and enhance the expression of VEGF mRNA in gastric ulcer rats. This might be the mechanism for JWYY accelerating the ulcer healing, and preventing the recurrence of gastric ulcer.

Analysis of the relationship between postoperative ophthalmic complications and dialysis time of prekidney transplantation

AIM: To determine the influence of the dialysis time before kidney transplantation on postoperative ophthalmic complications. METHODS: One hundred and eighty three patients who were given the follow-up after kidney transplantation were selected, including 124 males and 59 females. The dialysis time before kidney transplantation was (2.9 +/- 2.1) years. Among them, there were 93 cases having cadaveric renal transplantation and 90 cases having living relative renal transplantation. The conditions of ophthalmic complications in all the patients after kidney transplantation were investigated and the incidence rate on ophthalmic complications having different dialysis time before kidney transplantation was given Chi-square test and Chi-square linear trend test. RESULTS: Among 183 patients with kidney transplantation, 95 patients (51.9%) had at least one ophthalmic complication and the rest 88 patients (48.1%) had no significant abnormality at the eye region. The most common ophthalmic complications were pinguecula/conjunctival degeneration (31 cases), the following was caligo lentis (24 cases). The main manifestations were grayish white granule and plaque turbidity occurred in posterior capsule at the posterior pole of crystaline lens. The angulus iridocornealis of 5 patients (5.3%) with cataract and glaucoma were all open-angle through the detection by gonioscope. Through visual field examination, there were 2 patients with paracentral scotoma, 2 patients with arcuate scotoma and one case with nasal step. CONCLUSION: The experiments verify that the incidence of glaucomawas relates to the dialysis time before kidney transplantation, and the incidence rate might be higher if the dialysis time is longer.

Recent advances in the electrochemistry of layered post-transition metal chalcogenide nanomaterials for hydrogen evolution reaction

Layered two-dimensional(2 D)materials have received tremendous attention due to their unique physical and chemical properties when downsized to single or few layers.Several types of layered materials,especially transition metal dichalcogenides(TMDs)have been demonstrated to be good electrode materials due to their interesting physical and chemical properties.Apart from TMDs,post-transition metal chalcogenides(PTMCs)recently have emerged as a family of important semiconducting materials for electrochemical studies.PTMCs are layered materials which are composed of post-transition metals raging from main group IIIA to group VA(Ga,In,Ge,Sn,Sb and Bi)and group VI chalcogen atoms(S,selenium(Se)and tellurium(Te)).Although a large number of literatures have reviewed the electrochemical and electrocatalytic applications of TMDs,less attention has been focused on PTMCs.In this review,we focus our attention on PTMCs with the aim to provide a summary to describe their fundamental electrochemical properties and electrocatalytic activity towards hydrogen evolution reaction(HER).The characteristic chemical compositions and crystal structures of PTMCs are firstly discussed,which are different from TMDs.Then,inherent electrochemistry of PTMCs is discussed to unveil the well-defined redox behaviors of PTMCs,which could potentially affect their efficiency when applied as electrode materials.Following,we focus our attention on electrocatalytic activity of PTMCs towards HER including novel synthetic strategies developed for the optimization of their HER activity.This review ends with the perspectives for the future research direction in the field of PTMC based electrocatalysts.

A Universal Atomic Substitution Conversion Strategy Towards Synthesis of Large‑Size Ultrathin Nonlayered Two‑Dimensional Materials

Nonlayered two-dimensional(2D)materials have attracted increasing attention,due to novel physical properties,unique surface structure,and high compatibility with microfabrication technique.However,owing to the inherent strong covalent bonds,the direct synthesis of 2D planar structure from nonlayered materials,especially for the realization of large-size ultrathin 2D nonlayered materials,is still a huge challenge.Here,a general atomic substitution conversion strategy is proposed to synthesize large-size,ultrathin nonlayered 2D materials.Taking nonlayered CdS as a typical example,large-size ultrathin nonlayered CdS single-crystalline flakes are successfully achieved via a facile low-temperature chemical sulfurization method,where pre-grown layered CdI2 flakes are employed as the precursor via a simple hot plate assisted vertical vapor deposition method.The size and thickness of CdS flakes can be controlled by the CdI2 precursor.The growth mechanism is ascribed to the chemical substitution reaction from I to S atoms between CdI2 and CdS,which has been evidenced by experiments and theoretical calculations.The atomic substitution conversion strategy demonstrates that the existing 2D layered materials can serve as the precursor for difficult-to-synthesize nonlayered 2D materials,providing a bridge between layered and nonlayered materials,meanwhile realizing the fabrication of large-size ultrathin nonlayered 2D materials.

Structure of Micro-nano WC-10Co4Cr Coating and Cavitation Erosion Resistance in NaCl Solution

Cavitation erosion （CE） is the predominant cause for the failure of overflow components in fluid machinery. Advanced coatings have provided an effective solution to cavitation erosion due to the rapid development of surface engineering techniques. However, the influence of coating structures on CE resistance has not been sys- tematically studied. To better understand their relationship, micro-nano and conventional WC-10Co4Cr cermet coat- ings are deposited by high velocity oxygen fuel spray- ing（HVOF）, and their microstructures are analyzed by OM, SEM and XRD. Meanwhile, characterizations of mechan- ical and electrochemical properties of the coatings are carried out, as well as the coatings＇ resistance to CE in 3.5 wt % NaC1 solution, and the cavitation mechanisms are explored. Results show that micro-nano WC-10Co4Cr coating possesses dense microstructure, excellent mechanical and electrochemical properties, with very low porosity of 0.26 4-0.07% and extraordinary fracture toughness of 5.58 4-0.51 MPa.m1/2. Moreover, the CE resistance of micro-nano coating is enhanced above 50% than conventional coating at the steady CE period in 3.5 wt % NaC1 solution. The superior CE resistance of micro- nano WC-10Co4Cr coating may originate from the unique micro-nano structure and properties, which can effectively obstruct the formation and propagation of CE crack. Thus,a new method is proposed to enhance the CE resistance of WC-10Co4Cr coating by manipulating the microstructure.

NMR STUDIES ON THE WEAK INTERACTION OF FOUR-MONONUCLEOTIDES WITH TRYPTAMIDE AND LEUCINAMIDE

NMR spectroscopy analysis was introduced to investigate the weak interaction of four 5'—mononucleotides with tryptamide and leucinamide. Assuming a 1∶1 complex formation, the association constants were determined by nonlinear regression analysis. The association affinity of 4 mononucleotides with tryptamide decreased in the order: G>A>C>U, indicating that purine bases stack more strongly with tryptamide than pyrimidine bases. But with leucinamide the affinity decreases in the order: G>C>A=U, suggesting an amino acid—anticodonic preferential interaction. The implication of the present data to the origin of genetic code was briefly discussed.

初中物理虚像概念教学刍议

由实际光线形成的、能呈现在光屏上的像是实像;不是由实际光线形成的、不能在光屏上呈现只能用眼睛直接看到的像称为虚像。实践表明,较多的初中学生对“虚像不是由实际光线形成的”这一表述感到不可理解。本文希望通过虚像概念教学的分析研究,从学生思维角度和科学认知规律出发,总结出有效的虚像概念教学方法,提出教学改进策略。

具有泛化访花者的海芋特化传粉系统

特化传粉系统通常被认为是一种高效的植物与传粉者互作的关系,但即使是高度特化的花朵也经常接受非传粉者的访问。当前的特化传粉系统研究主要关注于植物与特定传粉者的相互作用,往往忽视了其他访花者的潜在影响。海芋(Alocasia odora)与芋果蝇属(Colocasiomyia)物种是典型的高度特化传粉互惠关系,但海芋花序仍存在许多其他的访花者类群,它们对传粉过程的影响尚不清楚。通过访花者筛除实验,本研究证实了海芋的授粉过程必须有海芋果蝇(C.alocasia)或异海芋果蝇(C.xenalocasiae)的参与。除此以外,海芋花序上还观察到包括露尾甲科、蜜蜂科、隐翅虫科和跗线螨科等类群的访花者,共计10种。繁育系统实验表明,海芋的自交不亲和性是由空间和时间上的雌雄分离造成的。因此,尽管其他访花者未直接对海芋结实率做出贡献,但它们对花粉和雄花不育区分泌物报酬的取食行为仍可能整体上减少了有效花粉资源,并与传粉者竞争报酬资源,进而间接影响有效传粉者的传粉行为。本研究为特化传粉理论提供了新视角,未来研究应更全面考虑访花者的整体作用。

Preparation and properties of ZrO_(2)-strengthened porous mullite insulation materials using Y_(2)O_(3) additive

ZrO_(2)-strengthened porous mullite insulation materials were prepared by foaming technology utilizing ZrSiO_(4) and Al_(2)O_(3) as primary materials and Y_(2)O_(3) as an additive.The effects of Y_(2)O_(3) contents on the phase composition,microstructure,mechanical properties,and heat conductivity of the porous mullite insulation materials were investigated.A suitable Y_(2)O_(3) content could promote phase transition of monoclinic ZrO_(2)(m-ZrO_(2))to tetragonal ZrO_(2)(t-ZrO_(2)),reduce pore size,and improve the strengths of as-prepared specimens.The cold crushing strength and bending strength of as-prepared specimens with a 119µm spherical pore size using 6 wt.%Y_(2)O_(3) were 35.2 and 13.0 MPa,respectively,with a heat conductivity being only 0.248 W/(m K).

Optimization for epitaxial fabrication of infinite-layer nickelate superconductors

The discovery of nickelates superconductor creates exciting opportunities to unconventional superconductivity. However, its synthesis is challenging and only a few groups worldwide can obtain samples with zero-resistance. This problem becomes the major barrier for this field. From plume dynamics perspective, we found the synthesis of superconducting nickelates is a complex process and the challenge is twofold, i.e., how to stabilize an ideal infinite-layer structure Nd_(0.8)Sr_(0.2)NiO_(2), and then how to make Nd_(0.8)Sr_(0.2)NiO_(2) superconducting? The competition between perovskite Nd_(0.8)Sr_(0.2)NiO_(3) and Ruddlesden−Popper defect phase is crucial for obtaining infinite-layer structure. Due to inequivalent angular distributions of condensate during laser ablation, the laser energy density is critical to obtain phase-pure Nd_(0.8)Sr_(0.2)NiO_(3). However, for obtaining superconductivity, both laser energy density and substrate temperature are very important. We also demonstrate the superconducting Nd_(0.8)Sr_(0.2)NiO_(2) epitaxial film is very stable in ambient conditions up to 512 days. Our results provide important insights for fabrication of superconducting infinite-layer nickelates towards future device applications.

含钛高炉渣的碳化产物对水泥砂浆强度及电阻率的影响

以攀枝花钢铁公司生产的高钛型高炉渣的碳化产物(碳化渣)取代标准砂为集料制备了水泥砂浆。采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对高钛型碳化渣进行了成分、物相和形貌表征;测试了不同碳化渣含量下水泥砂浆的抗压强度和电阻率,探讨了不同碳化渣取代量对水泥砂浆电阻率的影响机制。研究结果表明,含有碳化渣的水泥砂浆的强度满足建筑水泥砂浆的要求;在潮湿状态下,碳化渣的引入无法降低28 d龄期水泥砂浆的电阻率;在干燥状态下,当碳化渣的取代量达到60%以上时,水泥砂浆的电阻率可低于标准水泥砂浆,且最低可下降87.5%。高钛型碳化渣可作为导电集料的候选材料用于制备面向建筑加热采暖用的水泥基复合导电材料。

Aerosol scattering coefficients and major chemical compositions of fine particles observed at a rural site in the central Pearl River Delta,South China

During November–December 2010 aerosol scattering coefficients were monitored using a single-waved （525 nm） Nephelometer at a regional monitoring station in the central Pearl River Delta region and 24-hr fine particle （PM 2.5） samples were also collected during the period using quartz filters for the analysis of major chemical components including organic carbon （OC）,elemental carbon （EC）,sulfate,nitrate and ammonium.In average,these five components accounted for about 85% of PM 2.5 mass and contributed 42% （OC）,19% （SO 4 2 -）,12% （NO 3 -）,8.4% （NH 4＋） and 3.7% （EC）,to PM 2.5 mass.A relatively higher mass scattering efficiency of 5.3 m 2/g was obtained for fine particles based on the linear regression between scattering coefficients and PM 2.5 mass concentrations.Chemical extinction budget based on IMPROVE approach revealed that ammonium sulfate,particulate organic matter,ammonium nitrate and EC in average contributed about 32%,28%,20% and 6% to the light extinction coefficients,respectively.

Role of ammonia in forming secondary aerosols from gasoline vehicle exhaust

Ammonia(NH3) plays vital roles in new particle formation and atmospheric chemistry. Although previous studies have revealed that it also influences the formation of secondary organic aerosols(SOA) from ozonolysis of biogenic and anthropogenic volatile organic compounds(VOCs), the influence of NH3 on particle formation from complex mixtures such as vehicle exhausts is still poorly understood. Here we directly introduced gasoline vehicles exhausts(GVE) into a smog chamber with NH3 absorbed by denuders to examine the role of NH3 in particle formation from GVE. We found that removing NH3 from GVE would greatly suppress the formation and growth of particles. Adding NH3 into the reactor after 3 h photo-oxidation of GVE, the particle number concentration and mass concentrations jumped explosively to much higher levels, indicating that the numbers and mass of particles might be enhanced when aged vehicle exhausts are transported to rural areas and mixed with NH3-rich plumes. We also found that the presence of NH3 had no significant influence on SOA formation from GVE. Very similar oxygen to carbon(O:C) and hydrogen to carbon(H:C) ratios resolved by aerosol mass spectrometer with and without NH3 indicated that the presence of NH3 also had no impact on the average carbon oxidation state of SOA from GVE.

Oleic Acid and Eicosapentaenoic Acid Reverse Palmitic Acid-induced Insulin Resistance in Human HepG2 Cells via the Reactive Oxygen Species/JUN Pathway

Oleic acid(OA),a monounsaturated fatty acid(MUFA),has previously been shown to reverse saturated fatty acid palmitic acid(PA)-induced hepatic insulin resistance(IR).However,its underlying molecular mechanism is unclear.In addition,previous studies have shown that eicosapentaenoic acid(EPA),aω-3 polyunsaturated fatty acid(PUFA),reverses PA-induced muscle IR,but whether EPA plays the same role in hepatic IR and its possible mechanism involved need to be further clarified.Here,we confirmed that EPA reversed PA-induced IR in HepG2 cells and compared the proteomic changes in HepG2 cells after treatment with different free fatty acids(FFAs).A total of 234 proteins were determined to be differentially expressed after PA+OA treatment.Their functions were mainly related to responses to stress and endogenous stimuli,lipid metabolic process,and protein binding.For PA+EPA treatment,the PA-induced expression changes of 1326 proteins could be reversed by EPA,415 of which were mitochondrial proteins,with most of the functional proteins involved in oxidative phosphorylation(OXPHOS)and tricarboxylic acid(TCA)cycle.Mechanistic studies revealed that the protein encoded by JUN and reactive oxygen species(ROS)play a role in OA-and EPA-reversed PA-induced IR,respectively.EPA and OA alleviated PA-induced abnormal adenosine triphosphate(ATP)production,ROS generation,and calcium(Ca^(2+))content.Importantly,H_(2)O_(2)-activated production of ROS increased the protein expression of JUN,further resulting in IR in HepG2 cells.Taken together,we demonstrate that ROS/JUN is a common response pathway employed by HepG2 cells toward FFA-regulated IR.

Humidity and PM_(2.5) composition determine atmospheric light extinction in the arid region of northwest China

Atmospheric visibility can directly reflect the air quality.In this study,we measured watersoluble ions(WSIs),organic and element carbon(OC and EC)in PM 2.5 from September 2017 to August 2018 in Urumqi,NW China.The results show that SO4^2-,NO 3^(-)and NH4^(+)were the major WSIs,together accounting for 7.32%-84.12%of PM 2.5 mass.Total carbon(TC=OC+EC)accounted for 12.12%of PM 2.5 mass on average.And OC/EC>2 indicated the formation of secondary organic carbon(SOC).The levels of SO4^2-,NO3^(-)and NH4^(+)in low visibility days were much higher than those in high visibility days.Relative humidity(RH)played a key role in affecting visibility.The extinction coefficient(b ext)that estimated via Koschmieder formula with visibility was the highest in winter(1441.05±739.95 Mm-1),and the lowest in summer(128.58±58.00 Mm^(-)1).The b ext that estimated via IMPROVE formula with PM 2.5 chemical component was mainly contributed by(NH 4)2 SO4 and NH4 NO3.The b ext values calculated by both approaches presented a good correlation with each other(R^2=0.87).Multiple linear regression(MLR)method was further employed to reconstruct the empirical regression model of visibility as a function of PM 2.5 chemical components,NO_(2) and RH.The results of source apportionment by Positive Matrix Factorization(PMF)model showed that residential coal combustion and vehicle emissions were the major sources of b ext.