Danggui Shaoyao powder improves hepatic lipid metabolism in atherosclerosis mice via PPARγ-LXRα-ABCA1 pathway regulation

Objective:To observe the effects of Danggui Shaoyao powder(DSP)on hepatic lipid metabolism and further explore its mechanism of action by peroxisome proliferator-activated receptor(PPARγ)-liver X receptor(LXRα)-adenosine triphosphate(ATP)-binding cassette transporter A1(ABCA1)pathway regulation.Methods: Eight C57BL/6J male mice were selected as the control group,and 24 ApoE^(−/−)male mice were randomly divided into the atherosclerosis model(AS)group,atorvastatin calcium(AC)group,and DSP group(n=8 each group).To establish an AS model,ApoE^(−/−)mice were fed a high-fat diet for 16 weeks.Pathologic changes in the aortic vasculature and liver were identified using Oil Red O staining.Triglyceride(TG),cholesterol(TC),and low-density lipoprotein cholesterol(LDL-C)levels were determined in the livers using a single-reagent GPO-PAP method.Fluorescence quantitative polymerase chain reaction and western blot were used to observe and evaluate the mRNA and protein expression of the PPARγ-LXRα-ABCA1 intermediates in the liver.Results: After 16 weeks of a high-fat diet,ApoE^(−/−)mice showed more Oil Red O staining in the aorta and liver compared to the CONT group.Compared to the AS group,the DSP and AC treatment reduced aortic plaque and hepatic lipid deposition to varying degrees.Furthermore,DSP significantly reduced the hepatic lipid area in ApoE^(−/−)mice(P<.001)and decreased the levels of TG,TC,and LDL-C in liver(P<.001,P=.027,P<.001,respectively).DSP also significantly increased the levels of PPARγ,LXRα,ABCA1,and ABCG1 mRNA expression,as well as the PPARγ,LXRα,ABCA1,and ABCG1 protein expression in liver.Conclusion: DSP improved hepatic lipid metabolism via PPARγ-LXRα-ABCA1 pathway modulation for AS treatment.

光镍协同催化合成对甲氧基苯丙酮

光-镍协同催化反应是一种新兴的合成方法,具有产率高、条件温和、适用范围广等多种优点。我们以可持续发展理念为出发点,利用常见的工业原料芳香羧酸化合物和乙烯在温和的反应条件下高效合成了高附加值的芳基酮类化合物。该反应是第一例在空气氛围下光镍协同催化的芳基羧酸和工业气体乙烯的反应。这种方法实现了资源高效利用,操作简单,易于学生掌握,填补了基础有机化学实验教学中光化学反应相关内容的空白,具有重要的应用价值和教学价值。

Pressure-induced structural,electronic,and superconducting phase transitions in TaSe_(3)

TaSe_(3)has garnered significant research interests due to its unique quasi-one-dimensional crystal structure,which gives rise to distinctive properties.Using crystal structure search and first-principles calculations,we systematically investigated the pressure-induced structural and electronic phase transitions of quasi-one-dimensional TaSe_(3)up to 100 GPa.In addition to the ambient pressure phase(P2_(1)/m-I),we identified three high-pressure phases:P2_(1)/m-II,Pnma,and Pmma.For the P2_(1)/m-I phase,the inclusion of spin-orbit coupling(SOC)results in significant SOC splitting and changes in the band inversion characteristics.Furthermore,band structure calculations for the three high-pressure phases indicate metallic natures,and the electron localization function suggests ionic bonding between Ta and Se atoms.Our electron-phonon coupling calculations reveal a superconducting critical temperature of approximately 6.4 K for the Pmma phase at 100 GPa.This study provides valuable insights into the high-pressure electronic behavior of quasi-one-dimensional TaSe_(3).

The role of Toll-like receptors in non-infectious lung injury

The role of Toll-like receptors （TLRs） in pathogen recognition has been expeditiously advanced in recent years. However, investigations into the function of TLRs in non-infectious tissue injury have just begun. Previously, we and others have demonstrated that fragmented hyaluronan （HA） accumulates during tissue injury. CD44 is required to clear HA during tissue injury, and impaired clearance of HA results in unremitting inflammation. Additionally, fragmented HA stimulates the expression of inflammatory genes by inflammatory cells at the injury site. Recently, we identified that HA fragments require both TLR2 and TLR4 to stimulate mouse macrophages to produce inflammatory chemokines and cytokines. In a non-infectious lung injury model, mice deficient in both TLR2 and TLR4 show an impaired transepithelial migration of inflammatory cells, increased tissue injury, elevated lung epithelial cell apoptosis, and decreased survival. Lung epithelial cell overexpression of high molecular mass HA protected mice against acute lung injury and apoptosis, in part through TLR-dependent basal activation of NF-κB. The exaggerated injury in TLR2 and TLR4 deficient mice appears to be due to impaired HA-TLR interactions on epithelial cells. These studies identify that host matrix component HA and TLR interactions provide signals that initiate inflammatory responses, maintain epithelial cell integrity, and promote recovery from acute lung injury.

Research Progress of Drug Therapy for Diabetes

Diabetes is mainly a series of symptoms of glucose metabolism disorder caused by relative or absolute insufficiencies of insulin.Most patients are accompanied by protein,fat,water and electrolyte disorders,including diabetes type 1 and diabetes type 2,of which diabetes type 2 accounts for more than 90%.The incidence rate of diabetes is high,the course of disease is long,and it is difficult to cure.Most patients need long-term medication.This study analyzed the clinical manifestations and predisposing factors of diabetes,and explored the progress of drug treatment of diabetes,which is summarized as follows.

Lignin derived multi-doped(N, S, Cl) carbon materials as excellent electrocatalyst for oxygen reduction reaction in proton exchange membrane fuel cells

Nowadays,hierarchically macro-/meso-/microporous 3D carbon materials have been paid more attention due to their imaginative application potential in specific electrochemistry.Here,we report a dualtemplate strategy using eutectic NaCl/ZnCl2 melt as airtight and swelling agent to obtain 3D mesoporous skeleton structured carbon from renewable lignin.The prepared lignin-derived biocarbon material(LN-3-1)has a high specific surface area(1289 m^2 g^-1),a large pore volume(2.80 cm^3 g^-1),and a well-connected and stable structure.LN-3-1 exhibits extremely high activity and stability in acidic medium for oxygen reduction reaction(ORR),superior to Pt/C catalyst and most non noble-metal catalysts reported in recent literatures.The prepared carbon material was used as a cathode catalyst to assemble a H2-O2 single fuel cell,and its excellent catalytic performance has been confirmed with the maximum power density of 779 mW cm^-2,which is one of the highest power densities among non-metallic catalysts so far.Density functional theory(DFT)calculations indicate that the synergy of chlorine and nitrogen reconciles the intermediate adsorption energies,leading to an appropriate theoretical ORR onset potential.We develop a cost-effective and highly efficient method to prepare biocarbon catalyst for ORR in proton-exchange membrane fuel cells.

Transient thermo-mechanical analysis for bimorph soft robot based on thermally responsive liquid crystal elastomers

Thermally responsive liquid crystal elastomers (LCEs) hold great promise in applications of soft robots and actuators because of the induced size and shape change with temperature. Experiments have successfully demonstrated that the LCE based bimorphs can be effective soft robots once integrated with soft sensors and thermal actuators. Here, we present an analytical transient thermo-mechanical model for a bimorph structure based soft robot, which consists of a strip of LCE and a thermal inert polymer actuated by an ultra-thin stretchable open-mesh shaped heater to mimic the unique locomotion behaviors of an inchworm. The coupled mechanical and thermal analysis based on the thermo-mechanical theory is carried out to underpin the transient bending behavior, and a systematic understanding is therefore achieved. The key analytical results reveal that the thickness and the modulus ratio of the LCE and the inert polymer layer dominate the transient bending deformation. The analytical results will not only render fundamental understanding of the actuation of bimorph structures, but also facilitate the rational design of soft robotics.

Effect of Dachaihu decoction on non-alcoholic fatty liver disease model rats induced by a high-fat high-sugar diet

Objective:To establish an animal model consistent with the occurrence and development of non-alcoholic fatty liver disease(NAFLD)with which to assess the effects of a classical traditional Chinese medicine formula known as Dachaihu Decoction(DD)on NAFLD.Methods:Sixty rats were randomized into four groups:control,model,pioglitazone hydrochloride(PH)and DD in equal.NAFLD was produced via administration of a high-fat high-sugar diet for 16 weeks in all but the control group.From the 13th week,a solution of PH or DD prepared with water was delivered via intragastric administration to the PH and DD groups;the remaining two groups received an equivalent volume of distilled water.Twelve hours from the last administration,we selected eight rats from each group in random.After anesthetization,the abdominal aorta blood and liver tissues were collected.The morphological changes were observed and the levels of alanine aminotransferase(ALT),aspartate aminotransferase(AST),total cholesterol(TC),triglyceride(TG),low-density lipoprotein cholesterol(LDL-C),highdensity lipoprotein cholesterol(HDL-C),fasting plasma glucose(FBG),transforming growth factor-β1(TGF-β1),tumor necrosis factor-α(TNF-α),toll-like receptor-4(TLR4),and nuclear factor-kappa B(NF-κB)were tested.Results:Compared with the control group,the levels of serum ALT,AST,TC,TG,LDL-C and FBG,and TGF-β1,TNF-α,TLR4,NF-κB in the model group all showed significant increases(P<.01).Compared with the model group,these same indicators in the PH and DD groups all showed remarkable decreases(P<.05).Conclusion:The efficacy of DD in NAFLD rats was shown to be effectively equivalent to that of PH,with demonstrated effects of DD that included reductions in hepatic steatosis and serum and hepatic lipid levels,and lowered blood glucose levels.We deduce that DD has an inhibitory effect on NAFLD induced by a high-fat high-sugar diet in rats.

A multicenter randomized, double-blind, placebo-controlled trial to evaluate the safety and efficacy of rhubarb in treating acute exacerbation of chronic obstructive pulmonary disease of the syndrome type phlegm-heat obstructing the lungs

Objective:To observe the clinical efficacy and safety of oral administration of the traditional Chinese herb rhubarb to treat acute exacerbation of chronic obstructive pulmonary disease(AECOPD).Method:This was a multicenter randomized double-blinded placebo controlled study that took place in 7 provinces of China that enrolled 244 patients(aged 18e80 years)who had acute exacerbation of COPD with the traditional Chinese syndrome pattern of phlegm-heat obstructing lung.Participants were divided into experimental and control groups.The experimental group received 4.5 g of rhubarb granules twice daily and the control group received placebo granules.Both groups also received conventional Western therapy consisting of oxygen therapy,an antibiotic,expectorant,and a bronchodilator.Treatment lasted 10 days.Symptom scores for cough,sputum volume and color,wheezing and chest tightness before treatment and on days 3,5,7,and 10 during the treatment were recorded.Lung function,arterial blood gas and levels of serum inflammatory factors,interleukin-4(IL-4),interleukin-8(IL-8),and interleukin-10(IL-10)and tumor necrosis factor-alpha(TNF-a),before and after treatment were measured.Results:The sample size of the full analysis set(FAS)was 244 participants,and the sample size of per protocol set(PPS)was 235.Following 10 days’treatment,symptom scores of the experimental group were markedly lower than those of the placebo group(FAS:mean difference
1.67,95%CI:e2.66 to
0.69,P Z 0.001;PPS:mean difference
1.55,95%CI:
2.56 to
0.54,P Z 0.003).Lung function in the experimental group was significantly higher than in the placebo group(FEV1,FAS:mean difference 0.12,95%CI:0.06 to 0.18;P<0.001;PPS:mean difference 0.12,95%CI 0.05 to 0.18;P<0.001.FVC:FAS:mean difference 0.16,95%CI:0.06 to 0.26;P Z 0.002;PPS:mean difference 0.16,95%CI 0.05 to 0.26;P Z 0.003.FEV1%,FAS:mean difference 5.95,95%CI:3.36 to 8.53;P<0.001;PPS:mean difference 5.92,95%CI 3.28 to 8.56;P<0.001.).PaO2,PaCO2,as well as serum inflammatory factors were also improved when compared to the placebo group.There were no significant differences in the incidence rate of adverse reaction between the two groups.Conclusions:Compared with placebo,rhubarb granules significantly reduced symptom scores,improved blood oxygen level,controlled systemic inflammatory response,without significant adverse effects.Thus,rhubarb may be a beneficial adjuvant method for treating the phlegm-heat obstructing the lung syndrome pattern of AECOPD.

Effect of ephedrine hydrochloride on regulation of body fluid metabolism and AQP1 and AQP2 in a rabbit model of mechanical ventilation

Objective:Ephedrine hydrochloride(EH)is a major component from Ephedra sinica STAPF,which is used as a traditional Chinese herbal medicine.This study was designed to investigate the effect of EH on water metabolism and further explore the relevant signaling pathway of body fluid regulation in“lung governing regulation of water passage”using a rabbit model of mechanical ventilation.The molecular mechanism of the EH effect in the kidney was also investigated.Methods:Rabbits were randomly divided into a control group,model group,EH group,and dexmedetomidine hydrochloride(DH)group.Urine volume was measured by the intubation method and pathologic changes in lung and renal tissue were measured by hematoxylin and eosin staining.Nitric oxide(NO)production in lung,serum,and kidney were analyzed using chemical methods.An ELISA was used to analyze angiotensin II(Ang II),antidiuretic hormone(ADH),prostaglandin E2(PGE2),atrial natriuretic peptide(ANP),and endothelin-1(ET-1)levels in the lung,serum,and kidney.Aquaporin-1(AQP1)and aquaporin-2(AQP2)mRNA and protein expression in the kidney was determined using qRT-PCR and immunohistochemistry.Results:EH significantly inhibited the decrease in the total urine volume in the third and fourth stages,and displayed significant regulatory effects on NO,Ang II,ADH,PGE2,ANP,and ET-1 in serum,lung,and renal tissues compared with the model group.In the kidney,AQP1 and AQP2 mRNA and protein expression in the EH group were remarkably downregulated compared with the model group.Conclusion:EH exerted a regulatory effect on water metabolism by diffusing the lung and increased urine volume in the rabbit model,which was consistent with the decrease in kidney AQP1 and AQP2 expression levels that led to an increase in urine volume.EH could assist with DH to exert a protective effect on the clinical application of mechanical ventilation.

Application of geophysical well logs in solving geologic issues:Past,present and future prospect

Geophysical well logs are widely used in geological fields,however,there are considerable incompatibilities existing in solving geological issues using well log data.This review critically fills the gaps between geology and geophysical well logs,as assessed from peer reviewed papers and from the authors’personal experiences,in the particular goal of solving geological issues using geophysical well logs.The origin and history of geophysical logging are summarized.Next follows a review of the state of knowledge for geophysical well logs in terms of type of specifications,vertical resolution,depth of investigations and demonstrated applications.Then the current status and advances in applications of geophysical well logs in fields of structural geology,sedimentary geology and petroleum geology are discussed.Well logs are used in structural and sedimentary geology in terms of structure detection,in situ stress evaluation,sedimentary characterization,sequence stratigraphy division and fracture prediction.Well logs can also be applied in petroleum geology fields of optimizing sweet spots for hydraulic fracturing in unconventional oil and gas resource.Geophysical well logs are extending their application in other fields of geosciences,and geological issues will be efficiently solved via well logs with the improvements of advanced well log suits.Further work is required in order to improve accuracy and diminish uncertainties by introducing artificial intelligence.This review provides a systematic and clear descriptions of the applications of geophysical well log data along with examples of how the data is displayed and processed for solving geologic problems.

光催化酰基自由基与缺电子1,3-二烯的选择性1,6-加成反应实现羧酸的脱氧烯丙基化

缺电子1,3-二烯类化合物在有机合成和材料科学领域具有重要应用.由于共轭效应的影响,该类化合物的化学转化不同于普通烯烃.一方面,1,3-二烯有多个反应位点,可以合成结构多样化的有机化合物,但另一方面,多反应位点的存在会使其面临1,4-/1,6-区域选择性和Z/E立体选择性的难题.由于电子效应通过共轭π体系的传导差异,使得羰基1,3-二烯的δ位反应活性比β位低,因此1,6-加成反应较难发生.虽然过渡金属催化和有机催化方法的开发在一定程度上解决了1,6-加成选择性的问题,但使用温和的、易得的亲核体实现1,3-二烯的1,6-加成仍是一个难题.近年来,可见光驱动的光氧化还原催化提供了温和的自由基生成条件.一系列自由基前体被应用于不饱和羰基化合物的1,4-加成反应.然而,亲核碳自由基在1,6-加成反应中的应用非常少见,这是因为反应过程中生成的烯丙基自由基中间体容易进一步与二烯反应,发生聚合竞争反应.酰基自由基在有机转化中发挥了重要作用,基于前期本课题组在此方面的工作进展,本文利用可见光与有机膦的协同作用生成酰基自由基,通过酰基自由基对羰基1,3-二烯的1,6-共轭加成反应,实现了芳香羧酸的烯丙基化.经过对膦试剂、碱和反应溶剂等反应条件的筛选和优化,以86%的收率得到目标产物.随后,在此温和条件下对反应适用性进行考察,该反应对各种吸电子和给电子的邻、间、对位取代的芳香羧酸都具有很好的兼容性,各种官能团取代的(杂)芳香羧酸和环烯基甲酸与不同类型的羰基1,3-二烯均能顺利反应,以高达96%的收率高选择性地获得了一系列E构型的不饱和1,6-二羰基化合物.对于环酮缺电子二烯,利用该策略能够高选择性地合成共轭环烯酮.另外,将反应规模扩大至5 mmol时,反应收率几乎不受影响,成功实现了克级制备.自由基捕获实验表明酰基自由基参与了该反应.循环伏安法实验表明三(4-甲氧基苯基)膦能够很容易被失电子的光催化剂氧化,形成三芳基膦阳离子自由基,从而诱导羧酸脱氧.Stern-Volmer猝灭实验验证了激发态的光催化剂与羰基1,3-二烯的单电子转移过程,羰基1,3-二烯被还原为自由基阴离子中间体.酰基自由基能够迅速与其偶联生成阴离子中间体,随后经过质子化和异构化得到目标产物.综上,本文丰富了可见光催化芳香羧酸的脱氧官能团化反应类型,并为羰基1,3-二烯的转化提供了新的策略,为1,6-二羰基化合物的高效合成提供了一种新方法.

Extraction of transient signal from GPS position time series by employing ICA

Transient deformation,such as post-seismic slip,slow slip and pre-seismic slip events,is a limited lowfrequency deformation that can last for hours to months,in contrast to a sudden slip on a fault caused by earthquakes.Continuous Global Positioning System(CGPS),one of the most common geodetic techniques for continuously monitoring crustal deformation,is capable of capturing transient deformation signals.A critical point in characterizing transient deformation signals is the development of extracting and deciphering transient deformation signals from a huge and messy data set of position time series.Principal Component Analysis(PCA),one of the data-driven methods,has been employed to derive transient deformation signals from position time series combing with Kalman filtering.Independent Component Analysis(ICA)performs well in recovering and separating the sources of observed data,however,it is rarely used in extracting transient deformation signals.We aim to decompose the transient deformation signals from the daily GPS observation deployed in Akutan Island from 2007 to 2015 with the ICA method and obtain the spatiotemporal responses to the source signals of transient deformation.Our results indicate that ICA method can also characterize effectively transient deformation signals spatially and temporally.Additionally,the independent relationship between sources obtained by ICA allows for flexibility in linearly combining different sources.

Fast Segmentation Method of Sonar Images for Jacket Installation Environment

It has remained a hard nut for years to segment sonar images of jacket installation environment,most of which are noisy images with inevitable blur after noise reduction.For the purpose of solutions to this problem,a fast segmen-tation algorithm is proposed on the basis of the gray value characteristics of sonar images.This algorithm is endowed with the advantage in no need of segmentation thresholds.To realize this goal,we follow the undermentioned steps:first,calcu-late the gray matrix of the fuzzy image background.After adjusting the gray value,the image is divided into three regions:background region,buffer region and target regions.Afterfiltering,we reset the pixels with gray value lower than 255 to binarize images and eliminate most artifacts.Finally,the remaining noise is removed by morphological processing.The simulation results of several sonar images show that the algorithm can segment the fuzzy sonar images quickly and effectively.Thus,the stable and feasible method is testified.

Design of advanced porous silver powder with high-sintering activity to improve silicon solar cells

Silver(Ag)paste is widely used in semiconductor metallization,especially in silicon solar cells.Ag powder is the material with the highest proportion in Ag paste.The morphology and structure of Ag powder are crucial which determine its characteristics,especially for the sintering activity.In this work,a simple method was developed to synthesize a type of microcrystalline spherical Ag particles(SP-A)with internal pores and the structural changes and sintering behavior were thoroughly studied by combining ultra-small-angle X-ray scattering(USAXS),small-angle X-ray scattering(SAXS),in-situ heating X-ray diffraction(XRD),focused ion beam(FIB),and thermal analysis measurement.Due to the unique internal pores,the grain size of SP-A is smaller,and the coefficient of thermal expansion(CTE)is higher than that of traditional solid Ag particles.As a result,the sintering activity of SP-A is excellent,which can form a denser sintered body and form silver nanoparticles at the Ag–Si interface to improve silver silicon contact.Polycrystalline silicon solar cell built with SP-A obtained a low series resistance(Rs)and a high photoelectric conversion efficiency(PCE)of 19.26%.These fill a gap in Ag particle structure research,which is significant for the development of high-performance electronic Ag particles and efficient semiconductor devices.

Recent progress on the applications of micro/nanofibers in ultrafast optics

Ultrafast fiber lasers are indispensable components in the field of ultrafast optics,and their continuous performance advancements are driving the progress of this exciting discipline.Micro/Nanofibers(MNFs)possess unique properties,such as a large fractional evanescent field,flexible and controllable dispersion,and high nonlinearity,making them highly valuable for generating ultrashort pulses.Particularly,in tasks involving mode-locking and dispersion and nonlinearity management,MNFs provide an excellent platform for investigating intriguing nonlinear dynamics and related phenomena,thereby promoting the advancement of ultrafast fiber lasers.In this paper,we present an introduction to the mode evolution and characteristics of MNFs followed by a comprehensive review of recent advances in using MNFs for ultrafast optics applications including evanescent field modulation and control,dispersion and nonlinear management techniques,and nonlinear dynamical phenomenon exploration.Finally,we discuss the potential application prospects of MNFs in the realm of ultrafast optics.

Application of three-dimensional electron diffraction in structure determination of zeolites

Zeolites have received great attention due to their wide applications in various fields such as catalysis,adsorp-tion/separation,ion exchange,etc.Determining the atomic crystal structure of zeolites is crucial to understanding their functions and exploring their applications.Due to the difficulty of synthesizing large single crystals,the structures of many zeolites cannot be solved using conventional single-crystal X-ray diffraction(SCXRD)methods.Three-dimensional electron diffraction(3D ED)has witnessed rapid development during the past decade and has shown its powerful ability in the structure determination of zeolites.In this review,we will briefly introduce the history of 3D ED and summarize recent advances in the application of 3D ED for the analysis of zeolite structures,along with several typical examples in this research field.

Nonlinear encoding in diffractive information processing using linear optical materials

Nonlinear encoding of optical information can be achieved using various forms of data representation.Here,we analyze the performances of different nonlinear information encoding strategies that can be employed in diffractive optical processors based on linear materials and shed light on their utility and performance gaps compared to the state-of-the-art digital deep neural networks.For a comprehensive evaluation,we used different datasets to compare the statistical inference performance of simpler-to-implement nonlinear encoding strategies that involve,e.g.,phase encoding,against data repetition-based nonlinear encoding strategies.We show that data repetition within a diffractive volume(e.g.,through an optical cavity or cascaded introduction of the input data)causes the loss of the universal linear transformation capability of a diffractive optical processor.Therefore,data repetition-based diffractive blocks cannot provide optical analogs to fully connected or convolutional layers commonly employed in digital neural networks.However,they can still be effectively trained for specific inference tasks and achieve enhanced accuracy,benefiting from the nonlinear encoding of the input information.Our results also reveal that phase encoding of input information without data repetition provides a simpler nonlinear encoding strategy with comparable statistical inference accuracy to data repetition-based diffractive processors.Our analyses and conclusions would be of broad interest to explore the push-pull relationship between linear material-based diffractive optical systems and nonlinear encoding strategies in visual information processors.

A large eddy simulation of flows around an underwater vehicle model using an immersed boundary method

A large eddy simulation （LES） of the flows around an underwater vehicle model at intermediate Reynolds numbers is performed. The underwater vehicle model is taken as the DARPA SUBOFF with full appendages, where the Reynolds number based on the hull length is 1.0x 105, An immersed boundary method based on the moving-least-squares reconstruction is used to handle the complex geometric boundaries. The adaptive mesh refinement is utilized to resolve the flows near the hull, The parallel scalabilities of the flow solver are tested on meshes with the number of cells varying from 50 million to 3.2 billion, The parallel solver reaches nearly linear scalability for the flows around the underwater vehicle model, The present simulation captures the essential features of the vortex structures near the hull and in the wake, Both of the time-averaged pressure coefficients and srreamwise velocity profiles obtained from the LES are consistent with the characteristics of the flows pass an appended axisymmetric body. The code efficiency and its correct predictions on flow features allow us to perform the full-scale simulations on tens of thousands of cores with billions of grid points for higher-Reynolds-number flows around the underwater vehicles.

Metal-free carbocatalysis for electrochemical oxygen reduction reaction: Activity origin and mechanism

Although scientists have conducted long-term and extensive studies on oxygen reduction reaction(ORR)catalyzed by metal-free carbon materials,they mainly have focused on the preparation and properties of various doped carbon materials.There is still a lack of systematic scientific guidance on the relationship between the surface structure regulation and activity of carbon-based catalysts.In this review,some of electrochemical and computational fundamental concepts about ORR are concisely summarized.The effects of edge defect and nonmetallic doping of carbon materials on ORR behavior and mechanism have been reviewed,and activity origin identification and intermediate conversion mechanism have been discussed.The outlooks for future researches on metal-free ORR electrocatalysis are suggested.