基于CFD的具有首翼的新型飞翔形式AUV升力和阻力估计:对阻力极曲线和推力估计的见解

To achieve hydrodynamic design excellence in Autonomous Underwater Vehicles(AUVs)largely depends on the accurate prediction of lift and drag forces.The study presents Computational Fluid Dynamics(CFD)-based lift and drag estimations of a novel torpedo-shaped flight-style AUV with bow-wings.The horizontal bow-wings are provided to accommodate the electromagnetic arrays used to perform the cable detection and tracking operations near the seabed.The hydrodynamic performance of the AUV due to addition of these horizontal bow-wings is required to be investigated,particularly at the initial design stage.Hence,CFD techniques are employed to compute the lift and drag forces observed by the flight-style AUV,maneuvering underwater at different angles of attack and varying speeds.The Reynolds-Averaged Navier-Stokes Equations(RANSE)closure is achieved by employing the modified k-ϵ model and Two-Scale Wall Function(2-SWF)approach is used for boundary layer treatment.Further,the study also highlights the unique mesh refinement and solution-adaptive meshing techniques to perform the CFD simulations in Solidworks Flow Simulation(SWFS)environment.The drag polar curve for flight-style AUV with and without bow-wings is generated using the computed lift and drag coefficients.The curve provided essential insights for achieving hydrodynamically efficient and optimized AUV design.From the drag polar curve,it is revealed that due to horizontal bow-wings,the flight-style AUV is capable to generate higher lift with less drag and thus,it gives better lift-to-drag ratio compared to the AUV without bow-wings.Moreover,simulated results of axial drag observed by the AUV have also been compared with free-running experimental results and are found in good agreement.

Tumor-derived DEFB1 induces immune tolerance by inhibiting maturation of dendritic cell and impairing CD8+T cell function in esophageal squamous cell carcinoma

Objective:CD8+T cells are the key effector cells in the anti-tumor immune response.The mechanism underlying the infiltration of CD8+T cells in esophageal squamous cell carcinoma(ESCC)has not been clearly elucidated.Methods:Fresh ESCC tissues were collected and grouped according to the infiltration density of CD8+T cells.After the transcriptome sequencing on these samples and the combined analyses with The Cancer Genome Atlas(TCGA)ESCC data,a secreted protein DEFB1 was selected to explore its potential role in the infiltration of CD8+T cells.Bioinformatics analyses,histological verification and in vitro experiments were then performed.Results:DEFB1 was highly expressed in ESCC,and the high expression of DEFB1 was an independent risk factor for overall survival.Since the up-regulation or down-regulation of DEFB1 did not affect the proliferation,migration and apoptosis of ESCC cells,we speculated that the oncogenic effect of DEFB1 was achieved by regulating microenvironmental characteristics.Bioinformatics analyses suggested that DEFB1 might play a major role in the inflammatory response and anti-tumor immune response,and correlate to the infiltration of immature dendritic cell(imDC)in ESCC.Histological analyses further confirmed that there were less CD8+T cells infiltrated,less CD83+mature DC(mDC)infiltrated and more CD1a+imDC infiltrated in those ESCC samples with high expression of DEFB1.After the treatment with recombinant DEFB1 protein,the maturation of DC was hindered significantly,followed by the impairment of the killing effects of T cells in both 2D and 3D culture in vitro.Conclusions:Tumor-derived DEFB1 can inhibit the maturation of DC and weaken the function of CD8+T cells,accounting for the immune tolerance in ESCC.The role of DEFB1 in ESCC deserves further exploration.

哌柏西利联合内分泌治疗对78例激素受体阳性HER-2阴性晚期乳腺癌的疗效观察

目的:分析哌柏西利联合内分泌治疗的激素受体(hormone receptor,HR)阳性、HER-2阴性晚期乳腺癌临床疗效。方法:回顾性分析2018年9月至2019年12月78例于天津医科大学肿瘤医院行哌柏西利联合内分泌治疗HR阳性、HER-2阴性晚期乳腺癌患者的临床资料,并对其疗效与安全性进行分析。结果:78例患者的中位年龄为58岁,中位无进展生存期(progression-free survival,PFS)为7个月,总体客观缓解率(objective response rate,ORR)为36.7%(22/60),临床获益率(clinical benefit rate,CBR)为73.3%(44/60)。既往使用解救治疗<2线和≥2线的ORR分别为71.4%(20/28)和6.3%(2/32),两者比较差异具有统计学意义(P<0.001)。采用Cox比例风险回归模型多因素分析显示,转移部位数目、既往解救治疗线数和是否行解救化疗是哌柏西利联合内分泌治疗疗效的独立影响因素。不良事件中的中性粒细胞减少为96.2%(75/78)最常见,3~4级占62.8%(49/78),14.1%(11/78)患者因3~4级的白细胞减少/中性粒细胞减少而调整用药剂量。最常见的非血液学不良事件是乏力,占23.1%(18/78)。不良事件引起的停药发生率为7.7%(6/78)。结论:哌柏西利联合内分泌治疗更适合既往解救治疗线数少、未行解救化疗的患者,较后线使用有更好的疗效,且不良事件可控。

EHF通过抑制Wnt/β-catenin通路活性下调胰腺癌细胞的干性

目的:探索E26转化特异性同源因子(E26 transformation-specific homologous factor,EHF)调控胰腺癌细胞干性的机制。方法:通过生信分析寻找介导EHF调控胰腺癌干性的信号通路。利用Western blot及RT-qPCR技术验证胰腺癌细胞中EHF表达与目标干性通路活性的相关性。利用ChIP及双荧光素酶实验验证EHF对靶基因的调控作用。阻断通路活性后,利用功能学实验分析目标通路在EHF调控胰腺癌细胞干性过程中的作用。结果:生信分析发现Wnt/β-catenin通路参与EHF对胰腺癌干性的调控。构建EHF稳定过表达及稳定降表达的胰腺癌细胞系,通过Western blot及RT-qPCR技术证实胰腺癌细胞EHF的表达与Wnt/β-catenin通路的活性呈负相关,差异均具有统计学意义(均P<0.01)。EHF可通过结合β-catenin的启动子区直接抑制β-catenin的转录。通过流式细胞术、悬浮成球及软琼脂克隆形成实验证明,在利用XAV939阻断Wnt/β-catenin通路的活性后,由EHF敲低所引起的胰腺癌细胞干性上调可被有效抑制,差异均具有统计学差异(均P<0.01)。结论:EHF通过抑制Wnt/β-catenin通路活性下调胰腺癌细胞的干性,靶向Wnt/β-catenin通路的小分子抑制剂有潜力成为治疗胰腺癌的药物。

Achieving Fuzzy Matching Data Sharing for Secure Cloud-Edge Communication

In this paper,we propose a novel fuzzy matching data sharing scheme named FADS for cloudedge communications.FADS allows users to specify their access policies,and enables receivers to obtain the data transmitted by the senders if and only if the two sides meet their defined certain policies simultaneously.Specifically,we first formalize the definition and security models of fuzzy matching data sharing in cloud-edge environments.Then,we construct a concrete instantiation by pairing-based cryptosystem and the privacy-preserving set intersection on attribute sets from both sides to construct a concurrent matching over the policies.If the matching succeeds,the data can be decrypted.Otherwise,nothing will be revealed.In addition,FADS allows users to dynamically specify the policy for each time,which is an urgent demand in practice.A thorough security analysis demonstrates that FADS is of provable security under indistinguishable chosen ciphertext attack(IND-CCA)in random oracle model against probabilistic polynomial-time(PPT)adversary,and the desirable security properties of privacy and authenticity are achieved.Extensive experiments provide evidence that FADS is with acceptable efficiency.

The Enlightenment on Urban Ecological Construction by Research Progress of Sponge City in China Based on Literature Analysis

To quantitatively analyze main figure,field,agency and level of sponge city research in China,and clear research focus and hot spot in each year,by using the Full Text Database of Chinese Sci-tech Periodicals and other retrieval tools,the statistics and analysis of 3152 research literatures on sponge city published in domestic academic journals of 2004-2016 are conducted based on bibliometrics. It is found that since the concept of " sponge city" was firstly proposed in 2012,development research of sponge city involves 40 subject fields and is mainly published in 32 kinds of journals,which is dominated by natural science research( 1427 literatures). Researchers are mainly from each college and university,some design institutes and Chinese Academy of Sciences. The research could play certain guidance significance for further research and construction of ecological city construction in China.

Leisure Agriculture Based on Cultural Resources of Sani People in Yunnan

Through exploring the material and nonmaterial cultural resources in leisure agriculture of Sani People in Shilin of Yunnan Province,this paper introduced festivals,marriage,traditional clothing,and food culture of Sani People,and present the long history and brilliant culture of Sani People. These culture resources could be used to expand the cultural aspects of leisure agriculture,to solve the problems of low participation and less distinct characteristics. This study can provide a reference for building the high-end leisure agriculture with distinct characteristics of Yunnan Province,to form a new growth point for regional growth.

Therapeutic Effect and Mechanism of Jipei Dilong Ointment on Acute Soft Tissue Injury in Rats

[Objectives]This study was conducted to observe the therapeutic effect of Jipei Dilong Ointment on rats with acute soft tissue injury caused by heavy objects and to explore its action mechanism.[Methods]Thirty six rats were randomly divided into six groups(control group,model group,high-dose Jipei Dilong Ointment group(JP-H),medium-dose Jipei Dilong Ointment group(JP-M),low-dose Jipei Dilong Ointment group(JP-L)and diclofenac group).Except for the Control group,other groups were subjected to modeling of acute soft tissue injury by the weight impact method.All administration was performed once a day for nine consecutive days.The local appearance score and activity disorder score were determined after soft tissue injury in rats.HE staining was used to detect the pathological changes of injured soft tissues in rats.RT-PCR was used to detect the relative mRNA expressions of Bax,Bcl-2,MMP-9 and TIMP-1 in injured soft tissues of rats.Western Blot was used to detect the protein expressions of MMP-9,TIMP-1,TLR4,MyD88 and NF-κB p65 in injured soft tissues of rats.Results were statistically analyzed.[Results]Compared with the model group,Jipei Dilong Ointment could significantly improve the appearance symptoms such as swelling and ecchymosis in the injured area and the movement function of the affected limb(P<0.05).It could also improve the infiltration of inflammatory cells and widening of the intermuscular space caused by injury.Among them,the JP-H group and the diclofenac group had more significant curative effects.After 9 d of administration,each administration group could significantly up-regulate the ratio of Bcl-2/Bax mRNA expression level(P<0.05 or P<0.01),and the ratio of MMP-9/TIMP-1 mRNA expression level showed a downward trend(P>0.05).The expression level of NF-κB p65 protein in each administration group was significantly decreased(P<0.01).The protein expression levels of TLR4 and MyD88 and the ratio of MMP-9/TIMP-1 protein expression level in each administration group decreased to varying degrees.Among them,the JP-H group and diclofenac group significantly decreased(P<0.05).[Conclusions]Jipei Dilong Ointment has the functions of relieving pain,swelling and inflammation.It could improve the local appearance,functional activity and tissue morphology of affected limbs in rats,and has a therapeutic effect on acute soft tissue injury in rats.Its mechanism of action might be related to the inhibition of TLR4/MyD88/NF-κB p65 signaling pathway and the regulation of Bcl-2/Bax and MMP-9/TIMP-1 balance.

Protective Effect and Molecular Mechanism of Shui People's Classic Prescription Jipei Dilong Ointment on Osteoarthritis in Rats

[Objectives]To explore the protective effect and molecular mechanism of Shui People s Classic Prescription Jipei Dilong Ointment on knee osteoarthritis in rats.[Methods]72 SPF male SD rats were divided into control group,model group,Jipei Dilong Ointment high,medium and low dose groups,and positive drug Diclofenac group,with 12 rats in each group.Except the control group,all other groups were injected with 0.2 mL of 2%papain and 0.3%L-cysteine mixture into knee joint cavity to establish osteoarthritis model,while the control group was injected with the same amount of normal saline.The Lequesne MG score was used to determine the success of the model.After successful modeling,external administration was given for 4 weeks.The histopathological changes in articular cartilage and synovium were observed by HE staining;the levels of TNF-α,IL-1βand COX-2 in serum were detected by ELISA,and the relative expression of MMP-9 and TIMP-1 mRNA in cartilage was detected by qRT-PCR;the relative expression of MMP-9,TIMP-1,TLR4,MyD88 and NF-κB in rat cartilage was detected by Western-blot.[Results]Compared with the model group,Jipei Dilong Ointment could significantly reduce the Lequesne MG score and Mankin s score of arthritic rats(P<0.01);significantly improve the pathological changes in articular cartilage and synovium,reduce tissue edema,necrosis,inflammatory cell infiltration and fibrous tissue proliferation;reduce the expression of MMP-9 mRNA(P<0.01)in different degrees and increase the expression of TIMP-1 mRNA(P<0.01);reduce the relative expression of MMP-9,TLR4,MyD88 and NF-κB protein in different degrees(P<0.01),and significantly increase the relative expression of TIMP-1 protein in cartilage(P<0.01).[Conclusions]Jipei Dilong Ointment can improve the joint injury of osteoarthritis rats,and the mechanism may be related to the regulation of TLR4/MyD88/NF-κB signaling pathway and the ratio of MMP-9/TIMP-1.

MoS_(2)-g-C_(3)N_(4)纳米基气凝胶制备及其光热协同光催化净化染料废水

将界面太阳能水蒸发技术与光催化降解过程耦合被视为解决能源和环境问题的有效策略,但开发具有光热与催化协同效应的双功能蒸发器仍然具有挑战性.本文构建了MoS_(2)-g-C_(3)N_(4)(MG)异质结并将其负载于气凝胶上制备了一系列双功能的MoS_(2)-g-C_(3)N_(4)(MG)气凝胶蒸发器.这些MG气凝胶具有高比表面积、有效光吸收和高光催化活性,表现出优异的光热转换性能和光催化降解能力.MG气凝胶大的比表面积和丰富的孔隙结构不仅有利于水的渗透和蒸发焓的降低,还有利于有机污染物的吸附降解.其中,基于MG-0.4构筑的蒸发器具有1.72 kg m^(-2)h^(-1)的高水蒸发效率,同时表现出显著的罗丹明B降解效率(90.1%).这项工作为解决淡水短缺和水污染控制问题提供了一个新方法.

Functional characterization,structural basis,and protein engineering of a rare flavonoid 2′-O-glycosyltransferase from Scutellaria baicalensis

Glycosylation is an important post-modification reaction in plant secondary metabolism,and contributes to structural diversity of bioactive natural products.In plants,glycosylation is usually catalyzed by UDP-glycosyltransferases.Flavonoid 2′-O-glycosides are rare glycosides.However,no UGTs have been reported,thus far,to specifically catalyze 2′-O-glycosylation of flavonoids.In this work,UGT71AP2 was identified from the medicinal plant Scutellaria baicalensis as the first flavonoid 2′-O-glycosyltransferase.It could preferentially transfer a glycosyl moiety to 2′-hydroxy of at least nine flavonoids to yield six new compounds.Some of the 2′-O-glycosides showed noticeable inhibitory activities against cyclooxygenase 2.The crystal structure of UGT71AP2(2.15Å)was solved,and mechanisms of its regio-selectivity was interpreted by pKa calculations,molecular docking,MD simulation,MM/GBSA binding free energy,QM/MM,and hydrogen‒deuterium exchange mass spectrometry analysis.Through structure-guided rational design,we obtained the L138T/V179D/M180T mutant with remarkably enhanced regio-selectivity(the ratio of 7-O-glycosylation byproducts decreased from 48%to 4%)and catalytic efficiency of 2′-O-glycosylation(kcat/Km,0.23 L/(s·μmol),12-fold higher than the native).Moreover,UGT71AP2 also possesses moderate UDP-dependent de-glycosylation activity,and is a dual function glycosyltransferase.This work provides an efficient biocatalyst and sets a good example for protein engineering to optimize enzyme catalytic features through rational design.

基于CDEM的天然气水合物沉积物水力压裂裂纹扩展数值模拟

目前,天然气水合物开采存在储层渗透率低和热传导导致生产效率低等问题.作为一种常规油气勘探中有效提高储层渗透率的技术,水力压裂有望用于改善天然气水合物储层的渗透率,提高采收效率.然而,有关含天然气水合物沉积物(GHBS)水力压裂应用的研究却很少.本文采用有限元和离散元耦合的连续离散元法(CDEM),对不同地层性质的天然气水合物沉积物(GHBS)的水力压裂过程进行了二维的数值模拟,研究了储层性质和压裂参数对GHBS中裂缝生成的影响.主要结论是,在本研究考虑的压裂参数和沉积物性质中,内摩擦角越小、注入流量越大对产生裂缝越有利;当饱和度和黏聚力处于适当范围时,最有利于产生裂缝;当各方向的地应力相等时,最有利于压裂产生裂缝,但最不利于主要裂缝向更远的方向延伸.

大气细颗粒物中环境持久性自由基的分子特征与形成机理的研究

Aerosol-bound organic radicals,including environmentally persistent free radicals(EPFRs),are key components that affect climate,air quality,and human health.While putative structures have been proposed,the molecular characteristics of EPFRs remain unknown.Here,we report a surrogate method to characterize EPFRs in real ambient samples using mass spectrometry.The method identifies chemically relevant oxygenated polycyclic aromatic hydrocarbons(OxPAH)that interconvert with oxygen-centered EPFR(OC-EPFR).We found OxPAH compounds most relevant to OC-EPFRs are structurally rich and diverse quinones,whose diversity is strongly associated with OC-EPFR levels.Both atmospheric oxidation and combustion contributed to OC-EPFR formation.Redundancy analysis and photochemical aging model show pyrolytic sources generated more oxidized OC-EPFRs than photolytic sources.Our study reveals the detailed molecular characteristics of OC-EPFRs and shows that oxidation states can be used to identify the origins of OC-EPFRs,offering a way to track the development and evolution of aerosol particles in the environment.

Decision Aid Model for Private-owned Electric Vehicles Participating in Frequency Regulation Ancillary Service Market

To reduce the difficulty and enhance the enthusiasm of private-owned electric vehicles(EVs) in participating in frequency regulation ancillary service market(FRASM), a decision aid model(DAM) is proposed. This paper presents three options for EV participating in FRASM, i. e., the base mode(BM), unidirectional charging mode(UCM), and bidirectional charging/discharging mode(BCDM), based on a reasonable simplification of users' participating willingness. In BM, individual EVs will not be involved in FRASM, and DAM will assist users to set the optimal charging schemes based on travel plans under the time-of-use(TOU) price. UCM and BCDM are two modes in which EVs can take part in FRASM. DAM can assist EV users to create their quotation plan, which includes hourly upper and lower reserve capabilities and regulation market mileage prices. In UCM and BCDM, the difference is that only the charging rate can be adjusted in the UCM, and the EVs in BCDM can not only charge but also discharge if necessary. DAM can estimate the expected revenue of all three modes, and EV users can make the final decision based on their preferences. Simulation results indicate that all the three modes of DAM can reduce the cost, while BCDM can get the maximum expected revenue.

Ruthenium-lead oxide for acidic oxygen evolution reaction in proton exchange membrane water electrolysis

Developing an active and stable anode catalyst for the proton exchange membrane water electrolyzer(PEM-WE)is a critical objective to enhance the economic viability of green hydrogen technology.However,the expensive iridium-based electrocatalyst remains the sole practical material with industrial-level stability for the acidic oxygen evolution reaction(OER)at the anode.Ruthenium-based catalysts have been proposed as more cost-effective alternatives with improved activity,though their stability requires enhancement.The current urgent goal is to reduce costs and noble metal loading of the OER catalyst while maintaining robust activity and stability.In this study,we design a Ru-based OER catalyst incorporating Pb as a supporting element.This electrocatalyst exhibits an OER overpotential of 201 mV at 10 mA·cm^(-2),simultaneously reducing Ru noble metal loading by~40%.Normalization of the electrochemically active surface area unveils improved intrinsic activity compared to the pristine RuO_(2) catalyst.During a practical stability test in a PEM-WE setup,our developed catalyst sustains stable performance over 300 h without notable degradation,underscoring its potential for future applications as a reliable anodic catalyst.

Hydrogen Peroxide Electrosynthesis in a Strong Acidic Environment Using Cationic Surfactants

The two-electron oxygen reduction reaction(2e^(−)-ORR)can be exploited for green production of hydrogen peroxide(H_(2)O_(2)),but it still suffers from low selectivity in an acidic electrolyte when using non-noble metal catalysts.Here,inspired by biology,we demonstrate a strategy that exploits the micellization of surfactant molecules to promote the H_(2)O_(2)selectivity of a low-cost carbon black catalyst in strong acid electrolytes.The surfactants near the electrode surface increase the oxygen solubility and transportation,and they provide a shielding effect that displaces protons from the electric double layer(EDL).Compared with the case of a pure acidic electrolyte,we find that,when a small number of surfactant molecules were added to the acid,the H_(2)O_(2)Faradaic efficiency(FE)was improved from 12%to 95%H_(2)O_(2)under 200 mA cm^(−2),suggesting an 8-fold improvement.Our in situ surface enhanced Raman spectroscopy(SERS)and optical microscopy(OM)studies suggest that,while the added surfactant reduces the electrode’s hydrophobicity,its micelle formation could promote the O_(2) gas transport and its hydrophobic tail could displace local protons under applied negative potentials during catalysis,which are responsible for the improved H_(2)O_(2)selectivity in strong acids.

Formation, Identification and Colour Grading of Nanhong Agates from the Southwestern of China

Nanhong agate is widely welcomed in China because of its bright red colour.The pursuit of the red agate is the inheritance of Chinese red agate culture,which can be dated back to more than 3000 years ago.Field survey showed Nanhong agate geographically distributed in Yunnan and Sichuan provinces,the Southwestern of China(Fig.1).Geologically,Nanhong agate can be either produced as fillers in cracks and pores of the Late Permian E’meishan basalts,or as pebbles in the Early Triassic conglomerates and mudstones.Petrographic analyses reveal the formation of agates could be linked to the alteration of basalts by the silicon releasing in the process of transformation from pyroxene to chlorite.The formation of Nanhong agates could have experienced multi-stage alterations and crystallizations,which are supported by the occurrence of multi-stage chlorites and different homogenization temperatures of fluid inclusions bearing in the coarse grained quartz.The Nanhong agates are characterized by diffusely distributed hematite and/or goethite,causing the red to reddish orange in colour.These iron oxides occurre as aggregates showing dominantly spherical shapes and minor visible ellipsoid,hemisphere,radial and veil shape,with a size generally between 1.20μm and 43.21μm.Raman spectra,scanning electron microscopy,and high resolution transmission electron microscopy confirmed the present of hematite with single hematite particles smaller than 100 nm.Wide market survey of the selling Nanhong agates presented the quantified colour parameters,including hue,saturation,and brightness,obeying normal distribution in the Hue-Saturation-Brightness(HSB)colour space.After standardization,the hue(H)of Nanhong agate is mainly distributed in a range between[3.20°,17.52°]at a 95%confidence level.The saturation(S)and brightness(B)are mainly within[63.82%,92.69%]and[42.97%,75.37%],respectively.The Nanhong agates could be statistically classified as different grades by the Two Step Cluster analysis,which is objective compared to subjective visual evaluation.Factors causing the colour difference of Nanhong agates are attributed to the colour properties and distribution characteristics of hematite and goethite.The hue of Nanhong agate is dependent on the colour of the impurity minerals,hematite or goethite.Saturation is affected by the area ratio of impurity minerals.As the area ratio of impurity minerals is both affected by the distribution density and the average particle size,the saturation of Nanhong agate is the largest when the average particle size is near 10μm.No obvious correlation is observed between the brightness of Nanhong agates and their related properties and characteristics.

Transition-metal doped edge sites in vertically aligned MoS2 catalysts for enhanced hydrogen evolution

Highly active and low-cost catalysts for electrochemical reactions such as the hydrogen evolution reaction （HER） are crucial for the development of efficient energy conversion and storage technologies. Theoretical simulations have been instrumental in revealing the correlations between the electronic structure of materials and their catalytic activity, and guide the prediction and development of improved catalysts. However, difficulties in accurately engineering the desired atomic sites lead to challenges in making direct comparisons between experi- mental and theoretical results. In MoS2, the Mo-edge has been demonstrated to be active for HER whereas the S-edge is inert. Using a computational descriptor- based approach, we predict that by incorporating transition metal atoms （Fe, Co, Ni, or Cu） the S-edge site should also become HER active. Vertically standing, edge-terminated MoS2 nanofilms provide a well-defined model system for verifying these predictions. The transition metal doped MoS2 nanofilms show an increase in exchange current densities by at least two-fold, in agreement with the theoretical calculations. This work opens up further opportunities for improving electrochemical catalysts by incorporating promoters into particular atomic sites, and for using well-defined systems in order to understand the origin of the promotion effects.

Engineering the surface of LiCoO2 electrodes using atomic layer deposition for stable high-voltage lithium ion batteries

Developing advanced technologies to stabilize positive electrodes of lithium ion batteries under high-voltage operation is becoming increasingly important,owing to the potential to achieve substantially enhanced energy density for applications such as portable electronics and electrical vehicles.Here,we deposited chemically inert and ionically conductive LiAlO2 interfacial layers on LiCoO2 electrodes using the atomic layer deposition technique.During prolonged cycling at high-voltage,the LiAlO2 coating not only prevented interfacial reactions between the LiCoO2 electrode and electrolyte,as confirmed by electrochemical impedance spectroscopy and Raman characterizations,but also allowed lithium ions to freely diffuse into LiCoO2 without sacrificing the power density.As a result,a capacity value close to 200 mA＆#183;h＆#183;g-1 was achieved for the LiCoO2 electrodes with commercial level loading densities,cycled at the cut-off potential of 4.6 V vs.Li＋/Li for 50 stable cycles;this represents a 40% capacity gain,compared with the values obtained for commercial samples cycled at the cut-off potential of 4.2 V vs.Li＋/Li.

Morphology and property investigation of primary particulate matter particles from different sources

Particulate matter （PM） pollution has become a major environmental concern in many developing countries. PM pollution control remains a great challenge owing to the complex sources and evolution processes of PM particles. There are two categories of PM, i.e., primary and secondary PM particles, and the primary PM emissions play a key role in the formation of PM pollution. Knowledge of primary PM particle compositions, sources, and evolution processes is of great importance to the effective control of PM pollution. In order to characterize PM particles effectively, their fundamental properties including the morphology, concentration distribution, surface chemistry, and composition must be systematically investigated. In this study, we collected and analyzed six types of PM10 and PM2.s particles from different sources using an in situ sampling approach. The concentration distributions of PM particles were analyzed and comparative analysis of the morphologies, distributions, capture mechanisms, and compositions of PM particles was conducted using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectroscopy. We found that there were significant differences in the structures, morphologies, and capture mechanisms of PM2.5 and PM10 particles. The systematic comparative investigation in this work will benefit the study of evolution processes and the effective control of PM pollution in the future.