Metal-free two-dimensional phosphorene-based electrocatalyst with covalent P-N heterointerfacial reconstruction for electrolyte-lean lithium-sulfur batteries

The use of lithium-sulfur batteries under high sulfur loading and low electrolyte concentrations is severely restricted by the detrimental shuttling behavior of polysulfides and the sluggish kinetics in redox processes.Two-dimensional(2D)few layered black phosphorus with fully exposed atoms and high sulfur affinity can be potential lithium-sulfur battery electrocatalysts,which,however,have limitations of restricted catalytic activity and poor electrochemical/chemical stability.To resolve these issues,we developed a multifunctional metal-free catalyst by covalently bonding few layered black phosphorus nanosheets with nitrogen-doped carbon-coated multiwalled carbon nanotubes(denoted c-FBP-NC).The experimental characterizations and theoretical calculations show that the formed polarized P-N covalent bonds in c-FBP-NC can efficiently regulate electron transfer from NC to FBP and significantly promote the capture and catalysis of lithium polysulfides,thus alleviating the shuttle effect.Meanwhile,the robust 1D-2D interwoven structure with large surface area and high porosity allows strong physical confinement and fast mass transfer.Impressively,with c-FBP-NC as the sulfur host,the battery shows a high areal capacity of 7.69 mAh cm^(−2) under high sulfur loading of 8.74 mg cm^(−2) and a low electrolyte/sulfur ratio of 5.7μL mg^(−1).Moreover,the assembled pouch cell with sulfur loading of 4 mg cm^(−2) and an electrolyte/sulfur ratio of 3.5μL mg^(−1) shows good rate capability and outstanding cyclability.This work proposes an interfacial and electronic structure engineering strategy for fast and durable sulfur electrochemistry,demonstrating great potential in lithium-sulfur batteries.

Effect of nano-CaO particle on the microstructure,mechanical properties and corrosion behavior of lean Mg-1Zn alloy

The effects of nano-CaO contents on the microstructure,mechanical properties and corrosion resistance of lean Mg-1Zn alloy were investigated.The results showed that the addition of nano-CaO significantly refined the grain size and improved mechanical properties of the Mg-1Zn alloy.At the same time,CaO reacted with molten Mg in situ to form nano-MgO,whose corrosion product in SBF solution was the same with the degradation product of Mg matrix,resulting in the enhanced compactness of the Mg(OH)_(2) layer and reduced corrosion rate of matrix.The Mg-1Zn alloy had lower corrosion resistance due to excessively large grain size and shedding of corrosion products.The composite with 0.5 wt.%CaO had the best corrosion resistance with a weight loss of 9.875 mg·y^(-1)·mm^(-2)due to the small number of Ca_(2)Mg_(6)Zn_(3) phase and suitable grain size.While for composites with high content of CaO(0.7 wt.%and 1.0 wt.%),they had lower corrosion resistance due to the coexistence of large number of Ca_(2)Mg_(6)Zn_(3) and Mg_(2)Ca at grain boundaries,especially for 1.0 wt.%CaO composite,resulting from the strong micro-galvanic corrosion.

Update in lean metabolic dysfunction-associated steatotic liver disease

BACKGROUND A new nomenclature consensus has emerged for liver diseases that were previously known as non-alcoholic fatty liver disease(NAFLD)and metabolic dysfunction-associated fatty liver disease(MAFLD).They are now defined as metabolic dysfunction-associated steatotic liver disease(MASLD),which includes cardiometabolic criteria in adults.This condition,extensively studied in obese or overweight patients,constitutes around 30%of the population,with a steady increase worldwide.Lean patients account for approximately 10%-15%of the MASLD population.However,the pathogenesis is complex and is not well understood.AIM To systematically review the literature on the diagnosis,pathogenesis,characteristics,and prognosis in lean MASLD patients and provide an interpretation of these new criteria.METHODS We conducted a comprehensive database search on PubMed and Google Scholar between January 2012 and September 2023,specifically focusing on lean NAFLD,MAFLD,or MASLD patients.We include original articles with patients aged 18 years or older,with a lean body mass index categorized according to the World Health Organization criteria,using a cutoff of 25 kg/m2 for the general population and 23 kg/m2 for the Asian population.RESULTS We include 85 studies in our analysis.Our findings revealed that,for lean NAFLD patients,the prevalence rate varied widely,ranging from 3.8%to 34.1%.The precise pathogenesis mechanism remained elusive,with associations found in genetic variants,epigenetic modifications,and adaptative metabolic response.Common risk factors included metabolic syndrome,hypertension,and type 2 diabetes mellitus,but their prevalence varied based on the comparison group involving lean patients.Regarding non-invasive tools,Fibrosis-4 index outperformed the NAFLD fibrosis score in lean patients.Lifestyle modifications aided in reducing hepatic steatosis and improving cardiometabolic profiles,with some medications showing efficacy to a lesser extent.However,lean NAFLD patients exhibited a worse prognosis compared to the obese or overweight counterpart.CONCLUSION MASLD is a complex disease comprising epigenetic,genetic,and metabolic factors in its pathogenesis.Results vary across populations,gender,and age.Limited data exists on clinical practice guidelines for lean patients.Future studies employing this new nomenclature can contribute to standardizing and generalizing results among lean patients with steatotic liver disease.

Excellent complete conversion activity for methane and CO of Pd/TiO_2-Zr_(0.5)Al_(0.5)O_(1.75) catalyst used in lean-burn natural gas vehicles

Palladium catalysts are supported on TiO2, ZrO2, A12O3, Zro.sAlo.501.75 and TiO2-Zro.sAlo.501.75 prepared by co-precipitation method, re- spectively. Catalytic activities for methane and CO oxidation are evaluated in a gas mixture that simulated the exhaust from lean-burn natural gas vehicles （NGVs）. Pd/TiO2-Zro.sAlo.501.75 performs the best catalytic activity among the tested five catalysts. For CH4, the light-off temperature （Tso） is 254 ℃, and the complete conversion temperature （Tgo） is 280 ℃; for CO, Tso is 84 ℃, and Tgo was 96 ℃. Various techniques, including N2 adsorption-desorption, X-ray diffraction （XRD）, H2-temperature-programmed reduction （H2-TPR）, X-ray photoelec- tron spectroscopy （XPS）, and scanning electron microscopy （SEM） are employed to characterize the effect of supports on the physicochemical properties of prepared catalysts. N2 adsorption-desorption and SEM show that TiO2-Zro.5Al0.501.75 expresses uniform nano-particles and large meso-pore diameters of 26 nm. H2-TPR and XRD indicate that PdO is well dispersed on the supports and strongly interacted with each other. The results of XPS show that the electron density around PdO and the proportion of active oxygen on TiO2-Zro.sAl0.501.75 are maxima among the five supports.

Effect of cobalt oxide on performance of Pd catalysts for lean-burn natural gas vehicles in the presence and absence of water vapor

Pd-based catalysts modified by cobalt were prepared by co-impregnation and sequential impregnation methods,and characterized by X-ray powder diffraction （XRD）,N2 adsorption/desorption （Brunauer-Emmet-Teller method）,CO-chemisorption and X-ray photoelectron spectroscopy （XPS）.The activity of Pd catalysts was tested in the simulated exhaust gas from lean-burn natural gas vehicles.The effect of Co on the performance of water poisoning resistance for Pd catalysts was estimated in the simulated exhaust gas with and without the presence of water vapor.It was found that the effect of Co significantly depended on the preparation process.PdCo/La-Al2O3 catalyst prepared by co-impregnation exhibited better water-resistant performance.The results of XPS indicated that both CoAl2O4 and Co3O4 were present in the Pd catalysts modified by Co.For the catalyst prepared by sequential impregnation method,the ratio of CoAl2O4/Co3O4 was higher than that of the catalyst prepared by co-impregnation method.It could be concluded that Co3O4 played an important role in improving water-resistant performance.

Pd catalysts supported on modified Zr_(0.5)Al_(0.5)O_(1.75) used for lean-burn natural gas vehicles exhaust purification

Composite supports Zr0.5Al0.5O1.75 modified by metal oxides, such as La2O3, ZnO, Y2O3 or BaO, were prepared by co-precipitation method, and palladium catalysts supported on the modified composite supports were prepared by impregnation method. Their properties were characterized by X-ray diffraction （XRD）, NH3 temperature-programmed desorption （NH3-TPD）, He temperature-programmed reduction （He-TPR）, N2 adsorption/desorption, and CO-chemisorption. The catalytic activity and the resistance to water poisoning of the prepared Pd catalysts were tested in a simulated exhaust gas from lean-burn natural gas vehicles with and without water vapor. The results demonstrated that the modified supports had an apparent effect on the performance of Pd catalysts, compared with the Pd catalyst supported on the unmodified ZrA1. The addition of ZnO or Y203 promoted the conversion of CH4. In the absence of water vapor, Pd/ZnZrA1 exhibited the best activity for CH4 conversion with the light-off temperature （Tso） of 275 ℃ and the complete conversion temperature （T90） of 314 ℃, respectively. However, in the presence of water vapor, Pd/YZrA1 was the best one over which the light-off temperature （Tso） of methane was 339 ℃ and the complete conversion temperature （T90） was 371 ℃. These results indicated that Pd catalyst supported on the modified composite ZrA1 support showed excellent catalytic activity at low temperature and high resistance to H20 poisoning for the exhaust purification of lean-burn natural gas vehicles.

Boosting Lean Electrolyte Lithium-Sulfur Battery Performance with Transition Metals: A Comprehensive Review

Lithium–sulfur(Li–S) batteries have received widespread attention, and lean electrolyte Li–S batteries have attracted additional interest because of their higher energy densities. This review systematically analyzes the effect of the electrolyte-to-sulfur(E/S) ratios on battery energy density and the challenges for sulfur reduction reactions(SRR) under lean electrolyte conditions. Accordingly, we review the use of various polar transition metal sulfur hosts as corresponding solutions to facilitate SRR kinetics at low E/S ratios(< 10 μL mg~(-1)), and the strengths and limitations of different transition metal compounds are presented and discussed from a fundamental perspective. Subsequently, three promising strategies for sulfur hosts that act as anchors and catalysts are proposed to boost lean electrolyte Li–S battery performance. Finally, an outlook is provided to guide future research on high energy density Li–S batteries.

基于Lean管理理念的门诊医疗服务质量提升研究

目的分析在Lean管理理念基础上实施门诊护理管理对门诊医疗服务质量提升的影响。方法选取2021年1月—2022年12月在南京医科大学附属逸夫医院门诊工作的34名护理人员作为研究对象,2021年1—12月实施常规管理(实施前组),2022年1—12月实施Lean管理理念(实施后组)。比较实施前后护理质量、不良事件发生率及交接班质量评分。结果实施后组护理质量评分高于实施前组,差异有统计学意义(P<0.05)。实施后组护理差错、缺陷、纠纷发生率均低于实施前组,差异有统计学意义(P均<0.05)。实施后组护理人员交接班质量评分高于实施后组,差异有统计学意义(P<0.05)。结论Lean管理理念在门诊护理管理中的应用能有效提升护理质量,降低护理差错发生率,减少护患纠纷和投诉发生率,对提升门诊医疗服务质量具有积极意义。

回流区稳定燃烧的近熄火特性理论分析

基于火焰稳定在回流区剪切层中的假设,建立了预混火焰近贫燃熄火极限特性的理论分析模型.一旦火焰稳定在剪切层中,由于剪切层同时从两侧卷吸流体,所以进入火焰的流体将是自由流与回流区流体的混合物.如果是贫燃火焰,回流区流体由燃烧产物和多余的氧化剂组成而没有燃料,因此进入剪切层火焰的混合物当量比将低于自由流的当量比.如此一来,即使自由来流是可燃的,剪切层中混合物的当量比也可能超出可燃极限.分析表明,对于回流区稳定的贫燃火焰,进入剪切层火焰的混合物有效当量比将低于自由来流的当量比.根据理论分析建立了近贫燃熄火极限的回流区稳定燃烧模式图,其中涉及4个参数:自由来流当量比、剪切层卷吸比、吹熄极限和再点火极限.分析揭示出4种可能的燃烧模式:超稳定火焰、亚稳定火焰、振荡火焰和熄火.特别地,在参数空间发现了一个振荡区,它可能为近吹熄火焰引入一种新的固有不稳定性机制.在这种机制中,剪切层中的当量比振荡实际上是由燃烧过程本身驱动的,因为火焰的位置/振荡影响着进入回流区的流体成分进而影响剪切层中的当量比.因此,当量比振荡与燃烧过程之间的反馈循环由于周期性的火焰吹熄和闪回/再稳定而得以封闭.

稀燃条件下掺烧乙醇重整气对直喷汽油机燃烧及碳烟排放影响的仿真研究

为解决直喷汽油机稀薄气体的燃烧及排放问题,采用掺烧乙醇重整气改善直喷汽油机的性能,并利用CONVERGE三维仿真技术从微观角度解释发动机的性能表现。结果表明,引入乙醇重整气可以改善缸内当量比分布,促进H基、OH基的生成,有助于燃烧的良好进行;随重整气掺混比的升高,HO_(2)和H_(2)O_(2)分布范围更广、浓度更高,在燃烧室内分层现象更加明显;随着重整气掺混比增加到20%,缸内碳烟的生成质量和数量密度峰值分别降低了90%和56.25%,直喷汽油机碳烟排放得到有效改善。

成果导向下“精益”教学资源库建设模式的构建与实践

针对高职专业教学资源库建设中资源与岗位对接度不够、资源利用率不高、学习达成度评价体系不全等问题,提出了一种成果导向下的“精益”建设模式。“精益”建设模式以成果为导向,反向设计资源模块,项目式串联建设可复用颗粒化资源,精准化设置学习目标达成评价体系,教师可以基于学情数据,利用资源库资源搭建在线课程,满足不同学习者的学习需求,实现分层次差异化教学。实践表明该模式能有效服务于专业人才培养需求,高效益建设资源库资源,提高学生学习达成度,更好的服务于教师的教学需求,为职业教育资源库提供了一种参考模式。

Design Strategies for Leaning-Type Arch Bridges

This paper presents a study on the design strategy of leaning-type arch bridges.The main characteristics of leaning-type arch bridges are first introduced;Kunshan Yufeng Bridge is taken as an example to discuss different aspects of a design strategy,which includes self-system optimization,selection of beam length and bridge deck position,and other aspects.This paper can be used as a reference to further improve and develop bridge design.

DIP医保支付方式改革下医院多维联动精益运营管理研究

按病种分值付费(Diagnosis-Intervention Packet,DIP)医保支付方式改革的实施与落地对医院运营管理模式造成深远影响,使得医院的运营方式和管理内涵急需适配与优化。深度剖析DIP医保支付方式对于医院运营管理造成的影响,分别从病种分值政策的实施、医保成本核算控制、医疗服务质量提升、医保事后分析、病种管理等多个维度,对全生命周期视角DIP医保支付方式改革下医院运营管理模式的构建策略进行有力探索,以期更好地促进医院健康持续发展。

Pd(111)与Pt(111)上NO氧化的第一性原理研究

随着排放法规的日益严格,发动机的氮氧化物(NO_(x))后处理已成为当今研究的重点问题.针对目前可有效降低稀燃汽油机NO_(x)的稀燃氮氧化物捕集器中铂(Pt)和钯(Pd)两种贵金属之间的替换问题,进行了密度泛函理论(density functional theory,DFT)计算研究.首先,对一氧化氮(NO)、氧气(O_(2))、二氧化氮(NO_(2))在两种催化剂(111)表面的吸附进行了研究,之后,在两催化剂表面对比研究了氧化过程中涉及的O_(2)解离与NO氧化两反应过程,揭示了NO在Pd与Pt催化剂上的氧化机理.结果显示:3种物质在催化剂表面的吸附强度为NO>O_(2)>NO_(2).氧覆盖度将会改变氮氧化物的最佳吸附构型,随着表面氧原子的增加NO会由三重空位式吸附转变为顶点吸附,NO_(2)会由μ-N,O-亚硝基吸附转变为硝基吸附.在O_(2)解离过程中Pt的催化能力优于Pd,但是两者对NO氧化的催化能力接近.在Pd和Pt表面反应限速步骤都是O_(2)的解离,Pd对O_(2)较弱的解离能力导致了其NO的转化效率低于Pt.氧覆盖度对氧化过程存在影响,通过电子结构分析发现,氧覆盖度的提升使催化剂与吸附物质之间的吸附能下降,这导致了反应由吸热变为放热,使催化可以自发进行.反应生成的NO_(2)需要1.00 eV以上的能量完成脱附,这在原子层面解释了NO_(2)对NO氧化反应的抑制作用.

集中管理模式下精益六西格玛管理法对优化医疗设备维修管理的价值研究

目的研究集中管理模式下精益六西格玛(lean six sigma,LSS)管理法在优化生命支持类医疗设备维修管理流程方面的应用价值。方法以输液泵和注射泵为例,运用LSS管理方法中的界定、测量、分析、改进和控制5个阶段流程对生命支持类医疗设备维修管理难点进行分析,采用组织系统模型流程管理及鱼骨图等方法,分析影响设备维修管理的关键环节,提出在集中管理模式中简化维修审批流程、建立集中管理设备维修和质量控制运行机制、规范设备消毒和检测制度等改进方案,对LSS管理方法实施前后输液泵和注射泵实际维修周期和维修费用进行比较。结果LSS管理方法实施后,输液泵和注射泵设备实际维修时长分别缩短至(6.75±1.81)d和(5.89±1.25)d,维修周期分别缩短26.87%和20.19%,差异有统计学意义(P<0.05);输液泵和注射泵每月单次维修费用分别降低至232.10[32.50,291.00]元和164.40[32.80,183.40]元,差异有统计学意义(P<0.05);月均维修费用分别降低至1217.00元和1426.75元,分别降低了16.54%和28.20%,达到了LSS管理方法的工作目标。结论本研究提出的LSS管理方法可以有效分析医疗设备维修管理中的难点,从而在集中管理模式下针对性优化管理流程,可有效提升设备维修效率,降低维修成本。

精益管理改进肝癌手术患者体温护理的实践与探讨

目的探讨肝癌手术中体温护理现状,利用精益管理方法降低术中患者低体温发生率。方法分析2021年3—12月精益管理实施前和2022年3—12月精益管理实施后肝癌手术患者低体温状况,比较精益管理实施前后肝癌手术患者低体温发生率。结果实施前肝癌患者术中低体温发生率1绿卡1黄卡8红卡。实施后为9绿卡1红卡,差异具有统计学意义(p<0.05)。结论肝癌手术中患者低体温的影响因素较多,精益管理能够对造成低体温的原因实施干预以降低其发生。

基于约束理论的公立医院固定资产精益管理研究——以宁夏R医院为例

目的为了解决公立医院固定资产管理中存在的“管不清、管不好、用不好,重采买,轻管理”等主要问题,对公立医院固定资产管理进行探索。方法以约束理论(theory of constraints,TOC)为核心指导思想,结合现状分析,借助问卷调查、实地调研等方式寻找公立医院固定资产管理问题的关键影响因素。结果以问题为导向,重点从完善制度流程、系统有效使用、管理队伍建设、健全绩效考核及创新工作机制“五个关键环节”入手,构建了公立医院固定资产精益管理体系,固定资产日常规范高效管理、制度体系不断健全、管理队伍初步建成、动态管理基本实现。结论医院探索固定资产全生命周期管理,可有效提高公立医院固定资产精细化管理水平,确保国有资产的安全完整和有效使用。

面向准时化生产的船体分段排产分析

针对国内某典型船厂存在的智能化程度低、作业方案可控性差和库存成本高等问题,以减少船体分段的库存时间、满足分段的开工时间限制和保证胎位负荷均衡为目标建立数学模型,并引入遗传算法解决此类NP-Hard问题。在算法运行过程中采用混沌映射、精英保留策略和自适应交叉变异算子增强算法的全局寻优性和收敛性。对某船厂的实际生产数据进行计算和对比分析,结果表明,采用改进算法所得结果比船厂排产计划库存时间更少,资源利用率更高,该算法有效。

基于质量指标的隧道围岩智能分级及精益建造研究

隧道工程围岩级别的准确判识是围岩稳定性评价及隧道开挖精益支护的基础。围岩质量指标是围岩级别评判的依据,由于围岩质量指标计算包括定性与定量因素,存在定性指标难以准确评定,围岩级别精准评价困难的问题。采用围岩质量指标分级法与机器学习算法融合构建围岩智能分级软件系统,量化分析围岩分级质量指标要素,数值法求解围岩质量指标,围岩级别判定卡采集围岩要素,卡片信息软件系统自动识读、自动分析,快速判定围岩级别,精准确定支护参数,动态优化原支护设计方案。研究成果在3项隧道工程中实践应用,实现隧道围岩精准分级、精益支护建造的目标。

卡片导航平衡控制系统性能仿真研究

为了减少装配作业车间内因物料齐套产生的等待浪费,使具有装配约束的关联零件加工进度得到有效协同,设计一类卡片导航平衡控制系统(control of balance by card-based navigation,COBACABANA)。其基于两类卡片循环回路实现任务投放与作业分派的可视化进度协同控制逻辑。本文详细介绍系统的运行机制和系统控制参量,通过构建一般化的装配作业车间仿真模型,探讨在不同装配关联度下各控制参量的性能变化。实验结果表明,COBACABANA系统性能良好,并且选择合适的控制参量就能够有效提升关联零件的进度协同性。