Electrode structure enabling dendrite inhibition for high cycle stability quasi-solid-state lithium metal batteries

Lithium(Li)metal batteries(LMBs)are widely regarded as the ultimate choice for the next generation of high-energy–density batteries.However,the uncontrollable growth of Li dendrites formed by inhomogeneous deposition seriously hinders its commercialization.Although many studies have achieved significant results in inhibiting the formation of Li dendrites,it is still impossible to eradicate them completely.Therefore,regulating the deposition behavior,such as the growth direction of unevenly deposited Li,is preferable to unilaterally suppressing them in some cases.Here we report a structured anode that can confine the deposited Li within holes and tune it to become vertical-up/horizontal-centripetal mixed growth mode by optimizing the electric field/Li^(+)concentration gradient.The Li^(+) adsorbed by the poly(amic acid)(PAA)insulating layer coated on the anode surface can form the Li^(+)concentration gradient pointing to the center of the hole.Combined with the special electric field formed by the hole structure,it is favorable for the Li^(+)to move into the vertically arrayed holes and simultaneously deposit on the bottom and walls.Furthermore,both in-situ and ex-situ observations confirm that the growth mode is changed and the Li deposition morphology is denser,which can greatly delay capacity fading and prolong cycle life in both liquid and quasi-solid-state LMBs.All the results show that the novel anode provides a new perspective for deep research into solid-state LMBs.

A UV cross-linked gel polymer electrolyte enabling high-rate and high voltage window for quasi-solid-state supercapacitors

Serving as a promising alternative to liquid electrolyte in the application of portable and wearable devices,gel polymer electrolytes(GPEs)are expected to obtain more preferable properties rather than just be satisfied with the merits of high safety and deformability.Here,an easy-operated method is employed to fabricate cross-linked composite polymer membranes used for GPEs assisted by UV irradiation,in which N-doped carbon quantum dots(N-CQDs)and TiO2are introduced as photocatalysts and additives to improve the performances of GPEs.Specifically,N-CQDs participate as a cross-linker to construct the inner porous structure,and TiO2nanoparticles serve as a stabilizer to improve the electrochemical stability of GPEs under high voltage(3.5 V).The excellent thermal and mechanical stability of the membrane fabricated in this work guarantee the safety of the supercapacitors(SCs).This GPE based SC not only exhibits prominent rate performance(105%capacitance retention at the current density of 40A g^(-1))and cyclic stability(85%at 1 A g^(-1)under 3.5 V after 20,000 cycles),but also displays remarkable energy density(42.88 Wh kg^(-1))with high power density(19.3 k W kg^(-1)).Moreover,the superior rate and cycling performances of the as-prepared GPE based flexible SCs under flat and bending state confirm the feasibility of its application in flexible energy storage devices.

A Trusted Multi-Task Distribution Mechanism for Internet of Vehicles Based on Smart Contract

In this paper,a trusted multi-task distribution mechanism for Internet of Vehicles based on smart contract is proposed to improve the security and efficiency for the task distribution in Internet of Vehicles.Firstly,a three-tier trusted multi-task distribution framework is presented based on smart contract.The smart contract will be triggered by the task request.As the important part of the smart contract,the task distribution algorithm is stored on the blockchain and run automatically.In the process of the task distribution,the cost of the task distribution and the system stability play a critical role.Therefore,the task distribution problem is formulated to minimize the cost of the task distribution whilst maintaining the stability of the system based on Lyapunov theorem.Unfortunately,this problem is a mixed integer nonlinear programming problem with NP-hard characteristics.To tackle this,the optimization problem is decomposed into two sub problems of computing resource allocation and task distribution decision,and an effective task distribution algorithm is proposed.Simulation results show that the proposed algorithm can effectively improves system performance.

超声乳化白内障摘出联合CTR植入治疗高度近视并发白内障

目的:探究超声乳化白内障摘出联合囊袋张力环(CTR)植入治疗高度近视并发白内障患者的疗效,并分析其安全性。方法:回顾性分析我院186例186眼行超声乳化白内障摘出+人工晶状体(IOL)植入治疗的高度近视并发白内障患者临床资料,其中98例98眼联合CTR植入治疗(联合组),88例88眼未联合CTR植入治疗(对照组)。记录两组术前,术后1、3、6mo时最佳矫正视力(BCVA,LogMAR)、视觉质量[高阶像差的均方根值(RMS)]、角膜内皮细胞密度,评估术后1、3、6mo时前囊口面积、IOL倾斜角变化情况,并比较两组术后前囊膜混浊、后囊膜混浊、囊袋收缩综合征等并发症发生情况差异。结果:两组BCVA具有交互效应(P<0.05),两组术后BCVA值均较术前降低(P<0.05),且联合组术后BCVA值均低于对照组(P<0.05)。两组总高阶像差RMS具有交互效应(P<0.05),两组术后总高阶像差RMS均较术前升高(P<0.05),且联合组术后总高阶像差RMS均低于对照组(P<0.05)。两组术后前囊口面积具有交互效应(P<0.05),组内均随术后时间的延长而降低(P<0.05),且联合组术后3、6mo时均高于对照组(P<0.05)。两组术后IOL倾斜角具有交互效应(P<0.05),组内均随术后时间的延长而升高(P<0.05),且联合组术后3、6mo时均低于对照组(P<0.05)。两组术后角膜内皮细胞密度均较术前降低(P<0.05),但并无交互效应(P>0.05)。结论:超声乳化白内障摘出+IOL植入+CTR植入术可改善高度近视并发白内障患者视觉功能,术后并发症少,疗效及安全性良好。

A Fast Multi-tasking Solution: NMF-Theoretic Co-clustering for Gear Fault Diagnosis under Variable Working Conditions

Most gear fault diagnosis(GFD)approaches su er from ine ciency when facing with multiple varying working conditions at the same time.In this paper,a non-negative matrix factorization(NMF)-theoretic co-clustering strategy is proposed specially to classify more than one task at the same time using the high dimension matrix,aiming to o er a fast multi-tasking solution.The short-time Fourier transform(STFT)is first used to obtain the time-frequency features from the gear vibration signal.Then,the optimal clustering numbers are estimated using the Bayesian information criterion(BIC)theory,which possesses the simultaneous assessment capability,compared with traditional validity indexes.Subsequently,the classical/modified NMF-based co-clustering methods are carried out to obtain the classification results in both row and column tasks.Finally,the parameters involved in BIC and NMF algorithms are determined using the gradient ascent(GA)strategy in order to achieve reliable diagnostic results.The Spectra Quest’s Drivetrain Dynamics Simulator gear data sets were analyzed to verify the e ectiveness of the proposed approach.

New approach based on continuum damage mechanics with simple parameter identification to fretting fatigue life prediction

A new continuum damage mechanics model for fretting fatigue life prediction is established. In this model, the damage evolution rate is described by two kinds of quantities. One is associated with the cyclic stress characteristics obtained by the finite element （FE） analysis, and the other is associated with the material fatigue property identified from the fatigue test data of standard specimens. The wear is modeled by the energy wear law to simulate the contact geometry evolution. A two-dimensional （2D） plane strain FE implementation of the damage mechanics model and the energy wear model is presented in the platform of ABAQUS to simulate the evolutions of the fatigue damage and the wear scar. The effect of the specimen thickness is also investigated. The predicted results of the crack initiation site and the fretting fatigue life agree well with available experimental data. Comparisons are made with the critical plane Smith- Watson-Topper （SWT） method.

通过电沉积及氟硅烷改性而成的三维铜镍复合超疏水表面

将Cu-Ni微纳米颗粒电沉积在铝基底上,通过1H、1H、2H、2H-全氟癸基三甲氧基硅烷(FAS-17)对其进行修饰,制备了超双疏(SAP)表面.采用扫描电子显微镜、X射线衍射、能量色散X射线光谱和傅里叶变换红外光谱对其形貌和化学成分进行了研究.结果表明,SAP表面具有三维微纳结构,最大水接触角160.0°,油接触角151.6°.进一步测试了SAP表面的机械强度和化学稳定性,结果显示该SAP表面具有优良的耐磨性、耐酸耐碱性能、自洁性和防污性能.

Model Parameter Transfer for Gear Fault Diagnosis under Varying Working Conditions

Gear fault diagnosis technologies have received rapid development and been effectively implemented in many engineering applications.However,the various working conditions would degrade the diagnostic performance and make gear fault diagnosis(GFD)more and more challenging.In this paper,a novel model parameter transfer(NMPT)is proposed to boost the performance of GFD under varying working conditions.Based on the previous transfer strategy that controls empirical risk of source domain,this method further integrates the superiorities of multi-task learning with the idea of transfer learning(TL)to acquire transferable knowledge by minimizing the discrepancies of separating hyperplanes between one specific working condition(target domain)and another(source domain),and then transferring both commonality and specialty parameters over tasks to make use of source domain samples to assist target GFD task when sufficient labeled samples from target domain are unavailable.For NMPT implementation,insufficient target domain features and abundant source domain features with supervised information are fed into NMPT model to train a robust classifier for target GFD task.Related experiments prove that NMPT is expected to be a valuable technology to boost practical GFD performance under various working conditions.The proposed methods provides a transfer learning-based framework to handle the problem of insufficient training samples in target task caused by variable operation conditions.

China-invented vaccines against vacdnepreventable diseases for Belt&Road countries

Vaccine is a principal and highly cost-effective medical method on controlling infectious diseases and improving population health.Various vaccines are eagerly needed in the low-income countries along the Belt&Road.With the good quality to reach WHO prequalification standard,and the abundant capacity to fulfill the demand from market abroad,upon the platform of China-proposed"the Belt&Road Initiative",the vaccines manufactured in China are exporting to countries worldwide.The independent innovative vaccines'R&D system,which fruited a series of innovative infectious diseases vaccines(EV71 vaccine,sIPV,HEV,Ebola vaccine,etc.)to be launched in Chinese market,indicates that China has developed rapidly from"a great vaccine-production country"to"a powerful vaccine-innovation country".The implementation of National Innovation-driven Development Strategy would further push forward the developm ent and internationalization process of Chinese innovative vaccines.Therefore,the China-invented vaccines will make an important role in the prevention and control of infectious disease in various countries and become one of the most powerful weapons in fighting the global epidemic event in the future.

计及磨损的电连接器插拔力分析

电连接器在工程中使用量大,接触失效情况严重,一旦发生失效则有可能影响设备的正常使用甚至毁坏设备.针对电连接器接触失效占比率较高,且磨损对插拔力的影响规律未知等问题,本文以国产某型号电连接器为研究对象,建立电连接器的等效有限元模型,使用自适应网格技术和耗散能磨损模型进行磨损模拟,获得不同插拔次数下接触表面的磨损形貌,讨论不同插拔次数下磨损程度对电连接器插拔力的影响.结果表明,随着插拔次数的增加,电连接器表面的磨损会逐渐严重,插拔力的波动现象也会更加明显,且磨损对电连接器的拔出力影响较插入力更明显.

Effective and selective electrocatalytic nitrate reduction to ammonia on urchin-like and defect-enriched titanium oxide microparticles

This work reported a facile approach to surface oxygen vacancy(O_(v))-enriched urchin-like TiO_(2) microparticles(U-TiO_(2)),which were highly effective and durable in catalyzing selective nitrate reduction to ammonia(NOgRR),Specifically,the U-TiO_(2)delivered a mass activity of 1.15 min^(-1)mg^(-1)calyst.a low yield of toxic NO_(2)^(-)-N intermediate(≤0.4mg/L)and an exceptional high NH_(3)^(-)-N selectivity of 98.1%in treating 22.5 mg/L of NO_(3)^(-)-N under a potential of-0.60V vs.RHE,outperforming most of the reported oxidebased catalysts.When comparing the performance of U-TiO_(2)with that of the solid amorphous TiO_(2) counterpart(A-TiO_(2))that had close particle size but more O_(v) on surfaces,we identified that the O_(v) was the reactive sites,but rather than its content,the NO_(3)RR kinetics were primarily limited by the electron and mass transfer at U-TiO_(2)/water interfaces.Accordingly,the superior performance of U-TiO_(2)to A-TiO_(2)could be ascribed to the hierarchical urchin-like structure in U-TiO_(2).The in-situ DEMS test revealed that the NO_(3)RR on U-TiO_(2)followed a pathway of ^(*)NO_(3)^(-)→^(*)NO_(2)^(-)→^(*)NO→^(*)N→^(*)NH^(-)→^(*)NH_(2)→^(*)NH_(3).We also demonstrated that the U-TiO_(2) could keep its robust performance under a wide NO_(3)^(-)-N concentration range and in the presence of some co-existing ions(such as Ca^(2+),Cl^(-),Mg^(2+)).However,the presence of humic acid and CO_(3)^(2-) in water slowed down the NO_(3)RR on U-TiO_(2).This work provides a more fundamental insight into the O_(v)-driven NO_(3)RR process on TiO_(2),which should benefit for the development of eficient TiO_(2)-based catalvsts.

A new receiver clock model to enhance BDS-3 real-time PPP time transfer with the PPP-B2b service

A new Precise Point Positioning(PPP)service,called the PPP-B2b service,has been implemented in the BeiDou-3 Navigation Satellite System(BDS-3),which brings new opportunities for time transfer.However,the solution using the traditional PPP method with the PPP-B2b correction still absorbs some unknown errors and needs reconverging when there exist abnormal data.We developed a new receiver clock model to improve PPP time transfer using the PPP-B2b correction.The traditional PPP time transfers using PPP-B2b with BDS-3,Global Positioning System(GPS),and BDS-3/GPS(Scheme1)are compared with the corresponding time transfer with the proposed clock model(Scheme2).The results show that GPS-only PPP is not recommended because of low accuracy of 2 ns.BDS-3 or BDS-3/GPS PPP time transfers in Scheme1 can realize about 0.2 ns accuracy.When the new clock model is applied,the accuracy can be improved by up to 45%and 39.8%for BDS-3 and BDS-3/GPS PPP,respectively.The proposed clock model can signifcantly improve the short-term frequency stability by 57.4%,but less for the long-term stability.

One step hot-pressing method for hybrid Li metal anode of solid-state lithium metal batteries

Safety issues induced by infinite anode volume change and uncontrolled lithium(Li)dendrite growth have become the biggest obstacle to the practical application of Li metal batteries.In addition,the tra-ditional rolling method makes it difficult to manufacture thin Li foil with high mechanical strength and low Li content.Herein,a three-dimensional(3D)lithophilic carbon paper/copper(Cu)current collector hybrid anode with ultra-low Li metal content is prepared by a hot-pressing method.The highly re-versible and stable lithiophilic layer LiC_(x) formed in situ by heating/pressing treatment provides abun-dant nucleation sites and reduces the Li nucleation overpotential,thereby effectively suppressing Li den-drite growth.Moreover,the volume change and pulverization problems of Li metal anode during depo-sition/stripping also can be accommodated by the 3D skeleton.The optimization effect has been directly confirmed by in-situ optical and ex-situ scanning electron microscope observation.Therefore,highly sta-ble performance(158.4 mA h g^(-1) at 2 C after 200 cycles with a capacity retention of 95.24%)in Li@LCP-Cu||NCM811 coin cell can be achieved.Furthermore,the solid-state battery assembled with the hybrid anode,poly(vinylidene fluoride)(PVDF)-based polymer electrolyte and polyethylene oxide(PEO)interface functional layer also exhibits the best electrochemical and safety performance,which also proves that the Li@LCP-Cu anode has great potential for application in solid-state batteries.

LettuceGDB:The community database for lettuce genetics and omics

As a globally popular leafy vegetable and a representative plant of the Asteraceae family,lettuce has great economic and academic significance.In the last decade,high-throughput sequencing,phenotyping,and other multi-omics data in lettuce have accumulated on a large scale,thus increasing the demand for an integrative lettuce database.Here,we report the establishment of a comprehensive lettuce database,LettuceGDB(https://www.lettucegdb.com/).As an omics data hub,the current LettuceGDB includes two reference genomes with detailed annotations;re-sequencing data from over 1000 lettuce varieties;a collection of more than 1300 worldwide germplasms and millions of accompanying phenotypic records obtained with manual and cutting-edge phenomics technologies;re-analyses of 256 RNA sequencing datasets;a complete miRNAome;extensive metabolite information for representative varieties and wild relatives;epigenetic data on the genome-wide chromatin accessibility landscape;and various lettuce research papers published in the last decade.Five hierarchically accessible functions(Genome,Genotype,Germplasm,Phenotype,and O-Omics)have been developed with a user-friendly interface to enable convenient data access.Eight built-in tools(Assembly Converter,Search Gene,BLAST,JBrowse,Primer Design,Gene Annotation,Tissue Expression,Literature,and Data)are available for data downloading and browsing,functional gene exploration,and experimental practice.A community forum is also available for information sharing,and a summary of current research progress on different aspects of lettuce is included.We believe that LettuceGDB can be a comprehensive functional database amenable to data mining and database-driven exploration,useful for both scientific research and lettuce breeding.

工娱活动联合日间康复技术用于精神分裂症缓解期的效果观察

目的:观察工娱活动联合日间康复技术用于精神分裂症缓解期的治疗效果。方法:前瞻性选取2018年9月至2020年4月绍兴市第七人民医院收治的处于精神分裂症缓解期患者218例进行研究,将218例精神分裂症患者根据简单随机分组法分为观察组(109例)和对照组(109例),两组患者均采用常规药物治疗,对照组在此基础上采用日间康复技术治疗,观察组在对照组的基础上联合工娱活动治疗。治疗12周后,比较两组患者的治疗效果、阳性与阴性症状量表(PANSS)和蒙特利尔认知评估量表(MoCA)评分。结果:治疗12周后,观察组总有效率为91.74%,高于对照组的77.06%(χ^(2)=8.92,P<0.05);观察组的PANSS评分为(33.12±4.19)分,明显低于治疗前的(40.54±5.32)分(t=11.44,P<0.05),对照组的PANSS评分为(35.02±4.33)分,明显低于治疗前的(40.54±5.32)分(t=8.55,P<0.05),且观察组治疗后PANSS评分低于对照组(t=3.29,P<0.05);观察组的MoCA评分为(27.14±2.89)分,明显高于治疗前的(23.39±2.48)分(t=10.28,P<0.05),对照组的MoCA评分为(26.02±2.73)分,明显高于治疗前的(23.41±2.56)分(t=7.28,P<0.05),且观察组治疗后MoCA评分高于对照组(t=2.94,P<0.05)。结论:工娱活动联合日间康复技术治疗缓解期精神分裂症的疗效显著,可明显改善患者的精神症状和认知功能。

Ultrathin Al2O3-coated reduced graphene oxide membrane for stable lithium metal anode

Lithium （Li） metal has been considered as the most attractive anode materials for Li-ion batteries （LIBs） due to its high theoretic specific capacity. The formation of unstable solid electrolyte interphase （SEI） and dendritic Li on the metal anode, however, hindered its practical application. Herein, to address the issues, a Li-free electrode with ultrathin Al2O3 coated on reduced graphene oxide （rGO） membrane that covers a Cu foil current collector was developed. The composite electrode exhibits excellent interfacial protection of lithium metal deposited between Cu foil and rGO electrochemically. Firstly, it affords good Li^＋ permeability from the electrolyte. Secondly, the ultrathin Al2O3 has sufficient mechanical strength to inhibit the penetration of Li dendrite. Li metal was observed uniformly deposited between rGO membrane and Cu collector, and stable cycle performance of Li plating/stripping with Coulombic efficiency of ~ 91.75% at the lOOth cycle is achieved in organic carbonate electrolyte without any additives.

An Overview of Contour Detection Approaches

Object contour plays an important role in fields such as semantic segmentation and image classification. However, the extraction of contour is a difficult task, especially when the contour is incomplete or unclosed. In this paper, the existing contour detection approaches are reviewed and roughly divided into three categories： pixel-based, edge-based, and region-based. In addition, since the traditional contour detection approaches have achieved a high degree of sophistication, the deep convolutional neural networks （DCNNs） have good performance in image recognition, therefore, the DCNNs based contour detection approaches are also covered in this paper. Moreover, the future development of contour detection is analyzed and predicted.

A NEW DAMAGE MECHANICS BASED APPROACH TO FATIGUE LIFE PREDICTION AND ITS ENGINEERING APPLICATION

An approach based on continuum damage mechanics to fatigue life prediction for structures is proposed. A new fatigue damage evolution equation is developed, in which the pa- rameters are obtained in a simple way with reference to the experimental results of fatigue tests on standard specimens. With the utilization of APDL language on the ANSYS platform, a finite element implementation is presented to perform coupling operation on damage evolution of mate- rial and stress redistribution. The fatigue lives of some notched specimens and a Pitch-change-link are predicted by using the above approach. The calculated results are validated with experimental data.

Effects of disinfection efficiency on microbial communities and corrosion processes in drinking water distribution systems simulated with actual running conditions

The effects of disinfection efficiency on microbial communities and the corrosion of cast iron pipes in drinking water distribution systems(DWDSs) were studied.Two annular reactors(ARs) that simulated actual running conditions with UV/Cl2 disinfection and chlorination alone were used.High chlorine consumption and corrosion rate were found in the AR with UV/Cl2.According to functional genes and pyrosequencing tests, a high percentage of iron recycling bacteria was detected within the biofilm of the AR with Cl2 at early running stage, whereas siderophore-producing bacteria were dominant in the biofilm of the AR with UV/Cl2.At the early running stage, the sequential use of UV light and an initial high chlorine dosage suppressed the biomass and iron-recycling bacteria in both bulk water and biofilms, thereby forming less protective scales against further corrosion, which enhanced chlorine consumption.Non-metric multidimensional scaling analysis showed that the bacterial communities in the ARs shaped from within rather than being imported by influents.These results indicate that the initial high disinfection efficiency within the distribution system had not contributed to the accumulation of iron-recycling bacteria at the early running stages.This study offer certain implications for controlling corrosion and water quality in DWDSs.

Occurrence and risk assessment of typical PPCPs and biodegradation pathway of ribavirin in wastewater treatment plants

A large number of pharmaceuticals and personal care products(PPCPs)persist in wastewater,and the consumption of PPCPs for COVID-19 control and prevention has sharply increased during the pandemic.This study investigated the occurrence,removal efficiency,and risk assessment of six typical PPCPs commonly used in China in two wastewater treatment plants(WWTPs).Ribavirin(RBV)is an effective pharmaceutical for severely ill patients with COVID-19,and the possible biodegradation pathway of RBV by activated sludge was discovered.The experimental results showed that PPCPs were detected in two WWTPs with a detection rate of 100%and concentrations ranging between 612 and 2323 ng L^(-1).The detection frequency and concentrations of RBV were substantially higher,with a maximum concentration of 314 ng L^(-1).Relatively high pollution loads were found for the following PPCPs from influent:ibuprofen>ranitidine hydrochloride>RBV>ampicillin sodium>clozapine>sulfamethoxazole.The removal efficiency of PPCPs was closely related to adsorption and biodegradation in activated sludge,and the moving bed biofilm reactor(MBBR)had a higher removal capacity than the anoxic-anaerobic-anoxicoxic(AAAO)process.The removal efficiencies of sulfamethoxazole,ampicillin sodium,ibuprofen,and clozapine ranged from 92.21%to 97.86%in MBBR process and were relatively low,from 61.82%to 97.62%in AAAO process,and the removal of RBV and ranitidine hydrochloride were lower than 42.96%in both MBBR and AAAO processes.The discrepancy in removal efficiency is caused by temperature,hydrophilicity,and hydrophobicity of the compound,and acidity and alkalinity.The transformation products of RBV in activated sludge were detected and identified,and the biodegradation process of RBV could be speculated as follows:first breaks into TCONH_(2) and an oxygen-containing five-membered heterocyclic ring under the nucleosidase reaction,and then TCONH_(2) is finally formed into TCOOH through amide hydrolysis.Aquatic ecological risks based on risk quotient(RQ)assessment showed that PPCPs had high and medium risks in the influent,and the RQ values were all reduced after MBBR and AAAO treatment.Ranitidine hydrochloride and clozapine still showed high and medium risks in the effluent,respectively,and thus presented potential risks to the aquatic ecosystem.