The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods t...The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods to address the cooling challenge for high-power devices in DCs.Hybrid nanofluid(HNF)has the advantages of high thermal conductivity and good rheological properties.This study summarizes the numerical investigations of HNFs in mini/micro heat sinks,including the numerical methods,hydrothermal characteristics,and enhanced heat transfer technologies.The innovations of this paper include:(1)the characteristics,applicable conditions,and scenarios of each theoretical method and numerical method are clarified;(2)the molecular dynamics(MD)simulation can reveal the synergy effect,micro motion,and agglomeration morphology of different nanoparticles.Machine learning(ML)presents a feasiblemethod for parameter prediction,which provides the opportunity for the intelligent regulation of the thermal performance of HNFs;(3)the HNFs flowboiling and the synergy of passive and active technologies may further improve the overall efficiency of liquid cooling systems in DCs.This review provides valuable insights and references for exploring the multi-phase flow and heat transport mechanisms of HNFs,and promoting the practical application of HNFs in chip-level liquid cooling in DCs.展开更多
Most data centers currently tap into existing power grids to draw the immense amount of electricity they need to operate.But many of the data centers that Google(Mountain View,CA,USA)plans to open in the next few year...Most data centers currently tap into existing power grids to draw the immense amount of electricity they need to operate.But many of the data centers that Google(Mountain View,CA,USA)plans to open in the next few years will boast their own power plants,an arrangement known as colocation[1].Under an agreement announced in December 2024,the company will site data centers in industrial parks where its partner Intersect Power of Houston,TX,USA,has installed clean power facilities[1,2].The first of these complexes is scheduled to come online in 2026[1].展开更多
In the last two decades,seismic resilience(SR)has been developed as a main concept for the assessment of the structural vulnerabilities of buildings and city centres.In particular,historical centers consist of adjacen...In the last two decades,seismic resilience(SR)has been developed as a main concept for the assessment of the structural vulnerabilities of buildings and city centres.In particular,historical centers consist of adjacent buildings organized in blocks with common characteristics and similar typologies.The paper proposes a meth-odology to quantify SR for urban regions,by overcoming the state of the art studies that focus on assessing the SR for singular buildings.In this regard,the presented methodology may calculate the SR of blocks of buildings for the assessment of recovery investments of historical city centers.The main idea is to assess the level of vulnerability by accurate 3D surveys and visual inspections in order to select empirical fragility curves.The proposed methodology was herein applied to the city center of San Marino,designated by UNESCO as a world heritage site.展开更多
The negatively charged nitrogen vacancy(NV^(−))center ensemble in as-grown chemical vapor deposition(CVD)diamond is a promising candidate for quantum sensing due to its long coherence time and excellent optical proper...The negatively charged nitrogen vacancy(NV^(−))center ensemble in as-grown chemical vapor deposition(CVD)diamond is a promising candidate for quantum sensing due to its long coherence time and excellent optical properties.However,achieving a high concentration of NV^(−)centers in as-grown CVD diamond remains a critical challenge,which constrains the performance of NV^(−)based sensors.In this study,we observe that NV^(−)center formation efficiency is significantly enhanced during the initial growth phase,with a coherence time T_(2)^(*)of 1.1μs.These findings demonstrate that high-concentration NV^(−)centers can be achieved in as-grown diamonds,greatly enhancing their utility in high-performance magnetometers and quantum sensing.展开更多
Single negatively charged nitrogen vacancy(NV-)centers in diamond have emerged as promising platforms for quantum information science,where long coherence times are essential for advancing quantum technologies.However...Single negatively charged nitrogen vacancy(NV-)centers in diamond have emerged as promising platforms for quantum information science,where long coherence times are essential for advancing quantum technologies.However,traditional fabrication methods often introduce lattice damage during the irradiation process used to create vacancies,significantly impairing the spin coherence properties of NV-centers.展开更多
The properties and creation of optical centers in diamond are essential for applications in quantum technology.Here,we study the photoluminescence(PL)spectroscopy behavior at low temperatures of diamond subjected to e...The properties and creation of optical centers in diamond are essential for applications in quantum technology.Here,we study the photoluminescence(PL)spectroscopy behavior at low temperatures of diamond subjected to electron irradiation and annealing heat treatment.Through temperature variation testing,it was found that the NVcenter intensity of diamond with a nitrogen content of 150 ppm before treatment is insensitive to the experimental temperature,but significantly increases with decreasing temperature after treatment,showing sensitivity to temperature.In addition,the H3 center also shows an increasing trend with decreasing temperature.The results of annealing diamond with a nitrogen content of 730 ppm showed that even at a low temperature of 93 K,no NV^(-)centers were detected,but there were a large number of Ni-N related centers,especially NE8 centers.Our findings can promote a deeper understanding of the behavioral characteristics of HPHT-diamond optical centers in low-temperature environments.展开更多
The collaborative development of future learning centers in engineering university is a crucial component of integrating education,technology,and talent development.Its essence lies in cultivating top-notch innovative...The collaborative development of future learning centers in engineering university is a crucial component of integrating education,technology,and talent development.Its essence lies in cultivating top-notch innovative engineering talents with both scientific and technological literacy and humanistic feelings for the great rejuvenation of the Chinese nation through a historical narrative and a deep understanding of engineering talent cultivation in China.By tracing back to the formation of educator Mei Yiqi’s engineering intentions,the integration of engineering knowledge,and the history of engineering education governance,this paper proposes the key to the collaborative development of future learning centers in engineering university in the era of artificial intelligence.Firstly,it is necessary to update educational concepts and view learners as dynamically self-empowered individuals with plural existences.Secondly,attention should be paid to dynamic knowledge of possibilities,and cross-subject and interdisciplinary cognition and reflection should be carried out based on the types of engineering knowledge.Thirdly,it is essential to establish an engineering talent cultivation model with problem-guided knowledge learning as the core.With the support of digital network platforms and artificial intelligence technology,an infinite link of ideas and knowledge can be established through comprehensive textual methods,constructing learners’own“infinite library”and a spiritual world that is proactive,creative,and cultural.展开更多
In this paper,we develop an inexact symmetric proximal alternating direction method of multipliers(ISPADMM)with two convex combinations(ISPADMM-tcc)for solving two-block separable convex optimization problems with lin...In this paper,we develop an inexact symmetric proximal alternating direction method of multipliers(ISPADMM)with two convex combinations(ISPADMM-tcc)for solving two-block separable convex optimization problems with linear equality constraints.Specifically,the convex combination technique is incorporated into the proximal centers of both subproblems.We then approximately solve these two subproblems based on relative error criteria.The global convergence,and O(1/N)ergodic sublinear convergence rate measured by the function value residual and constraint violation are established under some mild conditions,where N denotes the number of iterations.Finally,numerical experiments on solving the l1-regularized analysis sparse recovery and the elastic net regularization regression problems illustrate the feasibility and effectiveness of the proposed method.展开更多
Despite extensive investigation into various electrocatalysts to enhance the progressive redox transformations of sulfur species in Li-S batteries(LSBs),their catalytic abilities are often hindered by suboptimal adsor...Despite extensive investigation into various electrocatalysts to enhance the progressive redox transformations of sulfur species in Li-S batteries(LSBs),their catalytic abilities are often hindered by suboptimal adsorption-desorption dynamics and slow charge transfer.Herein,a representative Co_(0.1)Mo_(0.9)P/MXene heterostructure electrocatalyst with optimal p-band centers and interfacial charge redistribution is engineered as a model to expedite bidirectional redox kinetics of sulfur via appropriate Co doping and built-in electric field(BIEF)effect.Theoretical and experimental results corroborate that the optimal Co-doping level and BIEF heterostructure ad-justs the p-band center of active phosphorus sites in Co_(0.1)Mo_(0.9)P/MXene to optimize the adsorption properties and catalytic performance of sulfur species,the BIEF between Co_(0.1)Mo_(0.9)P and MXene significantly decreases the activation energy as well as Gibbs free energy of rate-determining step,accelerates interfacial electron/Li-transfer rate during cycling,thereby accelerating dual-directional sulfur catalytic conversion rate in LSBs.Consequently,the S/Co_(0.1)Mo_(0.9)P/MXene cathode attains a large initial capacity of 1357 mAh g^(-1)at 0.2 C and a 500-cycle long stability(0.071%decay rate per cycle)at 0.5 C.Impressively,the high-loading S/Co_(0.1)Mo_(0.9)P/MXene cathode(sulfur loading:5.2 mg cm^(-2))also presents a remarkable initial areal capacity(6.5 mAh cm^(-2))with superior cycling stability under lean electrolyte(4.8μL mg_(sulfur)^(-1))conditions,and its Li-S pouch cell delivers a high capacity of 1029.4 mAh g^(-1).This study enhances the comprehension of catalyst effect in Li-S chemistry and provides important guidelines for designing effective dual-directional Li-S catalysts.展开更多
The development of robust and active oxygen evolution reaction(OER)electrocatalysts is urgently desirable for the widespread implementation of proton exchange membrane water electrolyzers(PEMWE),yet remains a critical...The development of robust and active oxygen evolution reaction(OER)electrocatalysts is urgently desirable for the widespread implementation of proton exchange membrane water electrolyzers(PEMWE),yet remains a critical challenge.We propose a catalyst named U-IrRuO_(x)@IrRu(where“U”denotes“ultrathin”),which features a spontaneously formed amorphous oxide shell that synergistically optimizes the electronic structure and corrosion resistance.Combined experimental and theoretical studies reveal that the oxyphilic Ru-induced electronic modulation weakens Ir-O binding strength,thereby accelerating the rate-determining step of ^(*)OOH formation.In addition,the metallic alloy core functions as an electron reservoir,suppressing excessive oxidation of active sites while ensuring high conductivity.Due to these attributes,the U-IrRuO_(x)@IrRu demonstrates a low overpotential of 230 mV at 10 mA cm^(-2),outperforming commercial IrO_(2)(CM)by 65 mV.When integrated into a PEMWE with an ultra-low Ir loading of 0.25 mg_(Ir)cm^(-2),it delivers an industrial current density of 2 A cm^(-2)at 1.74 V and 3 A cm^(-2)at 1.836 V,surpassing the U.S.Department of Energy(DOE)2025 target.More impressively,the U-IrRuOx@IrRubased electrolyzer can stably operate for over 550 h,with an extremely low decay rate of 7.52μV h^(-1),corresponding to a predicted lifespan of 23,000 h with 90%performance retention.展开更多
BACKGROUND Renal cell carcinoma(RCC)is treated with surgical resection as the gold standard,as it is notoriously resistant to systemic therapy.Advancements with targeted therapies contribute to declining mortality,but...BACKGROUND Renal cell carcinoma(RCC)is treated with surgical resection as the gold standard,as it is notoriously resistant to systemic therapy.Advancements with targeted therapies contribute to declining mortality,but metastatic RCC(mRCC)survival remains poor.One possible factor is treatment at academic centers,which employ advanced providers and novel therapies.This study compared outcomes of mRCC in patients treated at academic/research facilities compared to those treated at non-academic centers.AIM To compare survival outcomes of mRCC and their various etiologies between academic and non-academic centers.METHODS The National Cancer Database was used to identify mRCC patients including all histology subtypes and stage IV disease.Descriptive statistics and Kaplan-Meier curves measured survival outcomes for user file facility types sorted into a binary academic/research and non-academic research variable.Multivariate logistic regression and Cox proportional hazard testing generated odds ratio and hazard ratio.Data was analyzed using Statistical Package for the Social Sciences version 29.0 using a significance level of P<0.05.RESULTS Overall,academic facility patients experienced greater 5-year and 10-year overall survival than non-academic facility patients.Treatment at non-academic facilities was associated with increased odds of death that persisted even after controlling for age,tumor size,sex,and distance traveled to treatment center.In comparison,nonacademic facility patients also experienced greater risk of hazard.CONCLUSION Patients with mRCC treated at academic/research facilities experienced increased survival compared to patients treated at non-academic facilities,were more likely to be younger,carry private insurance,and come from a large metropolitan area.They also were significantly more likely to receive surgery and adjuvant immunotherapy.展开更多
Data centers operate as physical digital infrastructure for generating,storing,computing,transmitting,and utilizing massive data and information,constituting the backbone of the flourishing digital economy across the ...Data centers operate as physical digital infrastructure for generating,storing,computing,transmitting,and utilizing massive data and information,constituting the backbone of the flourishing digital economy across the world.Given the lack of a consistent analysis for studying the locational factors of data centers and empirical deficiencies in longitudinal investigations on spatial dynamics of heterogeneous data centers,this paper develops a comprehensive analytical framework to examine the dynamic geographies and locational factors of techno-environmentally heterogeneous data centers across Chinese cities in the period of 2006–2021.First,we develop a“supply-demand-environment trinity”analytical framework as well as an accompanying evaluation indicator system with Chinese characteristics.Second,the dynamic geographies of data centers in Chinese cities over the last decades are characterized as spatial polarization in economically leading urban agglomerations alongside persistent interregional gaps across eastern,central,and western regions.Data centers present dual spatial expansion trajectories featuring outward radiation from eastern core urban agglomerations to adjacent peripheries and leapfrog diffusion to strategic central and western digital infrastructural hubs.Third,it is empirically verified that data center construction in Chinese cities over the last decades has been jointly influenced by supply-,demand-,and environment-side locational factors,echoing the efficacy of the trinity analytical framework.Overall,our findings demonstrate the temporal variance,contextual contingency,and attribute-based differentiation of locational factors underlying techno-environmentally heterogeneous data centers in Chinese cities.展开更多
The rapidly growing seaweed farming contributes to food,feed,biofuel,and biochemicals,with Indonesia being the largest exporter of raw seaweed(53.35%)but low in carrageenan derivative products(4.49%).Sustainable farmi...The rapidly growing seaweed farming contributes to food,feed,biofuel,and biochemicals,with Indonesia being the largest exporter of raw seaweed(53.35%)but low in carrageenan derivative products(4.49%).Sustainable farming supports SDG 13 and SDG 14 through emission reduction,marine ecosystem conservation,and increased biodiversity.However,its supply chain faces challenges in raw material availability,such as fluctuating harvests,inconsistent quality,limited logistics infrastructure,and market price volatility.Therefore,good environmental management is needed to optimize raw materials in carrageenan production through resource efficiency,environmentally friendly products,environmental regulations,and market and stakeholder awareness.This study identifies factors in the environment-based supply chain that influence the development of carrageenan production centers and analyzes their ecological impacts using quantitative SEM analysis.SEM analysis reveals that resource efficiency,waste management,environmental regulations,and stakeholder awareness and commitment are the main influencing factors.shows significant factors including raw material efficiency,waste management,and environmental regulations.Environmentally based supply chain integration for the development of carrageenan production center areas can be done by;focusing on sustainability and minimal environmental impact,support for achieving SDG 12,13,and 14,strategies for sustainable raw material management,circular economy,sustainability certification,renewable energy and environmentally friendly technology,and stakeholder collaboration and awareness.展开更多
Serpentine structured Co_(3)Si_(2)O_(5)(OH)_(4) is inexpensive,chemically stable,and electrochemically active in oxygen evolution reactions(OER).However,the OER activity of Co_(3)Si_(2)O_(5)(OH)_(4) materials is still...Serpentine structured Co_(3)Si_(2)O_(5)(OH)_(4) is inexpensive,chemically stable,and electrochemically active in oxygen evolution reactions(OER).However,the OER activity of Co_(3)Si_(2)O_(5)(OH)_(4) materials is still unfavorable due to the low active sites.Here,Mn^(2+)-doped Co_(3)Si_(2)O_(5)(OH)_(4) serpentine nanosheets with tuned d-band centers are achieved for efficient oxygen evolution in alkaline and neutral electrolytes.The Co_(x)Mn_(3−x)Si_(2)O_(5)(OH)_(4) serpentine nanosheets are synthesized by a simple hydrothermal method.The optimized Co_(2.4)Mn_(0.6)Si_(2)O_(5)(OH)_(4) serpentine nanosheets showed favorable OER overpotentials as well as stable durability in KOH solution and phosphate buffer solution,which were superior to most of the Co-based and Mn-based OER electrocatalysts.The in situ Raman spectroscopy shows that the materials are kept well in the electrochemical OER environments.Further density functional theory shows that the d-band center of Co_(x)Mn_(3−x)Si_(2)O_(5)(OH)_(4) serpentine nanosheets is shifted more upward in comparison with pristine Co_(3)Si_(2)O_(5)(OH)_(4).The changes in the d-band center increase the adsorption of intermediates,optimize the reaction steps,and lower the energy barriers of the OER.That is the main reason for the OER enhancement Mn^(2+)-doped Co_(3)Si_(2)O_(5)(OH)_(4).This work gives an efficient strategy to design cheap and stable electrocatalytic materials for OER in a broad pH environment.展开更多
With the advent of the digital economy,there has been a rapid proliferation of small-scale Internet data centers(SIDCs).By leveraging their spatiotemporal load regulation potential through data workload balancing,aggr...With the advent of the digital economy,there has been a rapid proliferation of small-scale Internet data centers(SIDCs).By leveraging their spatiotemporal load regulation potential through data workload balancing,aggregated SIDCs have emerged as promising demand response(DR)resources for future power distribution systems.This paper presents an innovative framework for assessing capacity value(CV)by aggregating SIDCs participating in DR programs(SIDC-DR).Initially,we delineate the concept of CV tailored for aggregated SIDC scenarios and establish a metric for the assessment.Considering the effects of the data load dynamics,equipment constraints,and user behavior,we developed a sophisticated DR model for aggregated SIDCs using a data network aggregation method.Unlike existing studies,the proposed model captures the uncertainties associated with end tenant decisions to opt into an SIDC-DR program by utilizing a novel uncertainty modeling approach called Z-number formulation.This approach accounts for both the uncertainty in user participation intentions and the reliability of basic information during the DR process,enabling high-resolution profiling of the SIDC-DR potential in the CV evaluation.Simulation results from numerical studies conducted on a modified IEEE-33 node distribution system confirmed the effectiveness of the proposed approach and highlighted the potential benefits of SIDC-DR utilization in the efficient operation of future power systems.展开更多
The enantioselective separation of racemate,particularly those containing C(sp^(3))-H bonds knowns for their high bond dissociation energies and significant polarity,presents a significant challenge in pharmaceutical ...The enantioselective separation of racemate,particularly those containing C(sp^(3))-H bonds knowns for their high bond dissociation energies and significant polarity,presents a significant challenge in pharmaceutical synthesis.Recent advances have witnessed the fusion of photocatalysis with hydrogen atom transfer(HAT)methodologies,marking a notable trend in synthesis of chiral molecules.This technique uses the excitation of a catalyst to activate substrates,enabling the selective isomerization of chiral centers containing C(sp^(3))configurations.This process distinctively facilitates the direct activation of the C(sp^(3))-H bond in targeted reagents.This review systematically discusses the photocatalytic isomerization of various chiral molecule featuring C(sp^(3))-H centers,capable of undergoing deracemization through two primary HAT mechanisms:direct and indirect pathways.From the perspective of synthetic organic chemistry,this field has progressed towards the development of isomerization strategies for molecules that incorporate an activating group at theα-position adjacent to the C(sp^(3))chiral center.Moreover,it covers methodologies applicable to molecules characterized by specific C-C and C-S bond configurations.The integration of photocatalysis with HAT technology thus provides valuable strategies for the synthesis of enantiopure compounds with enhanced selectivity and efficiency.展开更多
The rapid advancement of artificial intelligence(AI)has significantly increased the computational load on data centers.AI-related computational activities consume considerable electricity and result in substantial car...The rapid advancement of artificial intelligence(AI)has significantly increased the computational load on data centers.AI-related computational activities consume considerable electricity and result in substantial carbon emissions.To mitigate these emissions,future data centers should be strategically planned and operated to fully utilize renewable energy resources while meeting growing computational demands.This paper aims to investigate how much carbon emission reduction can be achieved by using a carbonoriented demand response to guide the optimal planning and operation of data centers.A carbon-oriented data center planning model is proposed that considers the carbon-oriented demand response of the AI load.In the planning model,future operation simulations comprehensively coordinate the temporal‒spatial flexibility of computational loads and the quality of service(QoS).An empirical study based on the proposed models is conducted on real-world data from China.The results from the empirical analysis show that newly constructed data centers are recommended to be built in Gansu Province,Ningxia Hui Autonomous Region,Sichuan Province,Inner Mongolia Autonomous Region,and Qinghai Province,accounting for 57%of the total national increase in server capacity.33%of the computational load from Eastern China should be transferred to the West,which could reduce the overall load carbon emissions by 26%.展开更多
In this paper we shall extend the paper [1] to a separate Taylor's Theorem with respect to a lot of centers, namely Newton's Theorem Of a lot of centers. From it we obtain the analogous results in the paper [2...In this paper we shall extend the paper [1] to a separate Taylor's Theorem with respect to a lot of centers, namely Newton's Theorem Of a lot of centers. From it we obtain the analogous results in the paper [2]. namely an interpolation formula of the difference of higher order. Finally we give their applications.展开更多
A survey of language training centers(LTCs)in Dalian,China was conducted,to ascertain the strengths and weaknesses,or the differentiating factors,of such centers.The survey was undertaken to understand the current lan...A survey of language training centers(LTCs)in Dalian,China was conducted,to ascertain the strengths and weaknesses,or the differentiating factors,of such centers.The survey was undertaken to understand the current landscape of after-school institutes in the region,particularly those that offer training in English as a second/foreign language.The information uncovered by the research is considered beneficial not only to entrepreneurs who may wish to be involved in this industry,but also to college English majors who may wish to teach at an LTC.展开更多
The increasing globalization of the Chinese economy has been enabled by both Chinese financial institutions operating globally as well as international firms operating within China. In geographical terms, this has bee...The increasing globalization of the Chinese economy has been enabled by both Chinese financial institutions operating globally as well as international firms operating within China. In geographical terms, this has been organized through a number of strategic cities serving as gateways for the exchange of financial functions, products and practices between China and the global economy. Drawing on location data of financial service firms in China listed on stock exchanges in Shenzhen, Shanghai and Hong Kong, this paper shows that Chinese financial firms are expanding globally and how Chinese financial centers are positioned and connected in the urban networks shaped by these financial service firms. It is found that Hong Kong, China, holds strategic positions in the integration of Chinese cities into global financial center networks, and that establishing a foothold in global financial centers such as New York and London has been a priority for Chinese financial institutions. The increasing capital flows directed by Chinese financial institutionssuggests a shifting global financial geography, with numerous Chinese cities playing increasingly important roles within global financial center networks.展开更多
基金funded by the Science and Technology Project of Tianjin(No.24YDTPJC00680)the National Natural Science Foundation of China(No.52406191).
文摘The growth of computing power in data centers(DCs)leads to an increase in energy consumption and noise pollution of air cooling systems.Chip-level cooling with high-efficiency coolant is one of the promising methods to address the cooling challenge for high-power devices in DCs.Hybrid nanofluid(HNF)has the advantages of high thermal conductivity and good rheological properties.This study summarizes the numerical investigations of HNFs in mini/micro heat sinks,including the numerical methods,hydrothermal characteristics,and enhanced heat transfer technologies.The innovations of this paper include:(1)the characteristics,applicable conditions,and scenarios of each theoretical method and numerical method are clarified;(2)the molecular dynamics(MD)simulation can reveal the synergy effect,micro motion,and agglomeration morphology of different nanoparticles.Machine learning(ML)presents a feasiblemethod for parameter prediction,which provides the opportunity for the intelligent regulation of the thermal performance of HNFs;(3)the HNFs flowboiling and the synergy of passive and active technologies may further improve the overall efficiency of liquid cooling systems in DCs.This review provides valuable insights and references for exploring the multi-phase flow and heat transport mechanisms of HNFs,and promoting the practical application of HNFs in chip-level liquid cooling in DCs.
文摘Most data centers currently tap into existing power grids to draw the immense amount of electricity they need to operate.But many of the data centers that Google(Mountain View,CA,USA)plans to open in the next few years will boast their own power plants,an arrangement known as colocation[1].Under an agreement announced in December 2024,the company will site data centers in industrial parks where its partner Intersect Power of Houston,TX,USA,has installed clean power facilities[1,2].The first of these complexes is scheduled to come online in 2026[1].
文摘In the last two decades,seismic resilience(SR)has been developed as a main concept for the assessment of the structural vulnerabilities of buildings and city centres.In particular,historical centers consist of adjacent buildings organized in blocks with common characteristics and similar typologies.The paper proposes a meth-odology to quantify SR for urban regions,by overcoming the state of the art studies that focus on assessing the SR for singular buildings.In this regard,the presented methodology may calculate the SR of blocks of buildings for the assessment of recovery investments of historical city centers.The main idea is to assess the level of vulnerability by accurate 3D surveys and visual inspections in order to select empirical fragility curves.The proposed methodology was herein applied to the city center of San Marino,designated by UNESCO as a world heritage site.
基金supported by the National Natural Science Foundation of China(Grant Nos.11374280 and 50772110).
文摘The negatively charged nitrogen vacancy(NV^(−))center ensemble in as-grown chemical vapor deposition(CVD)diamond is a promising candidate for quantum sensing due to its long coherence time and excellent optical properties.However,achieving a high concentration of NV^(−)centers in as-grown CVD diamond remains a critical challenge,which constrains the performance of NV^(−)based sensors.In this study,we observe that NV^(−)center formation efficiency is significantly enhanced during the initial growth phase,with a coherence time T_(2)^(*)of 1.1μs.These findings demonstrate that high-concentration NV^(−)centers can be achieved in as-grown diamonds,greatly enhancing their utility in high-performance magnetometers and quantum sensing.
基金supported by the National Natural Science Foundation of China(Grant Nos.112374012 and 11974208)Shandong Provincial Natural Science Foundation(Grant Nos.ZR2023JQ001 and tsqn202211128)。
文摘Single negatively charged nitrogen vacancy(NV-)centers in diamond have emerged as promising platforms for quantum information science,where long coherence times are essential for advancing quantum technologies.However,traditional fabrication methods often introduce lattice damage during the irradiation process used to create vacancies,significantly impairing the spin coherence properties of NV-centers.
基金supported by the National Natural Science Foundation of China(Grant Nos.12274373,12274372,and 12204259)the Natural Science Foundation of Henan Province(Grant No.242300421155)+2 种基金the Key Research Projects of Higher Education Institutions in Henan Province(Grant No.25A140008)the Science and Technology Base and Talent Project of Guangxi,China(Grant No.AD21220154)the Central Plains Science and Technology Innovation Youth Top Notch Talents.
文摘The properties and creation of optical centers in diamond are essential for applications in quantum technology.Here,we study the photoluminescence(PL)spectroscopy behavior at low temperatures of diamond subjected to electron irradiation and annealing heat treatment.Through temperature variation testing,it was found that the NVcenter intensity of diamond with a nitrogen content of 150 ppm before treatment is insensitive to the experimental temperature,but significantly increases with decreasing temperature after treatment,showing sensitivity to temperature.In addition,the H3 center also shows an increasing trend with decreasing temperature.The results of annealing diamond with a nitrogen content of 730 ppm showed that even at a low temperature of 93 K,no NV^(-)centers were detected,but there were a large number of Ni-N related centers,especially NE8 centers.Our findings can promote a deeper understanding of the behavioral characteristics of HPHT-diamond optical centers in low-temperature environments.
基金2024 General Research Topic of the Chinese Society of Educational Development Strategy,“Research on the Collaborative Development of‘Future Learning Centers’in Engineering University under New Strategic Needs”(Project No.:ZLB20240820)。
文摘The collaborative development of future learning centers in engineering university is a crucial component of integrating education,technology,and talent development.Its essence lies in cultivating top-notch innovative engineering talents with both scientific and technological literacy and humanistic feelings for the great rejuvenation of the Chinese nation through a historical narrative and a deep understanding of engineering talent cultivation in China.By tracing back to the formation of educator Mei Yiqi’s engineering intentions,the integration of engineering knowledge,and the history of engineering education governance,this paper proposes the key to the collaborative development of future learning centers in engineering university in the era of artificial intelligence.Firstly,it is necessary to update educational concepts and view learners as dynamically self-empowered individuals with plural existences.Secondly,attention should be paid to dynamic knowledge of possibilities,and cross-subject and interdisciplinary cognition and reflection should be carried out based on the types of engineering knowledge.Thirdly,it is essential to establish an engineering talent cultivation model with problem-guided knowledge learning as the core.With the support of digital network platforms and artificial intelligence technology,an infinite link of ideas and knowledge can be established through comprehensive textual methods,constructing learners’own“infinite library”and a spiritual world that is proactive,creative,and cultural.
基金supported by the National Natural Science Foundation of China(12171106)the Guangxi Science and Technology Program(AD23023001)+4 种基金the Natural Science Foundation of Guangxi Province(2023GXNSFBA026029)the National Natural Science Foundation of China(12401403,12361063)the Research Project of Guangxi Minzu University(2022KJQD03)the Middle-aged and Young Teachers’Basic Ability Promotion Project of Guangxi Province(2023KY0168)the Xiangsihu Young Scholars Innovative Research Team of Guangxi Minzu University(2022GXUNXSHQN04).
文摘In this paper,we develop an inexact symmetric proximal alternating direction method of multipliers(ISPADMM)with two convex combinations(ISPADMM-tcc)for solving two-block separable convex optimization problems with linear equality constraints.Specifically,the convex combination technique is incorporated into the proximal centers of both subproblems.We then approximately solve these two subproblems based on relative error criteria.The global convergence,and O(1/N)ergodic sublinear convergence rate measured by the function value residual and constraint violation are established under some mild conditions,where N denotes the number of iterations.Finally,numerical experiments on solving the l1-regularized analysis sparse recovery and the elastic net regularization regression problems illustrate the feasibility and effectiveness of the proposed method.
基金supported by the National Natural Science Foundation of China(No.51972066)the Natural Science Foundation of Guangdong Province of China(No.2024A1515012499).
文摘Despite extensive investigation into various electrocatalysts to enhance the progressive redox transformations of sulfur species in Li-S batteries(LSBs),their catalytic abilities are often hindered by suboptimal adsorption-desorption dynamics and slow charge transfer.Herein,a representative Co_(0.1)Mo_(0.9)P/MXene heterostructure electrocatalyst with optimal p-band centers and interfacial charge redistribution is engineered as a model to expedite bidirectional redox kinetics of sulfur via appropriate Co doping and built-in electric field(BIEF)effect.Theoretical and experimental results corroborate that the optimal Co-doping level and BIEF heterostructure ad-justs the p-band center of active phosphorus sites in Co_(0.1)Mo_(0.9)P/MXene to optimize the adsorption properties and catalytic performance of sulfur species,the BIEF between Co_(0.1)Mo_(0.9)P and MXene significantly decreases the activation energy as well as Gibbs free energy of rate-determining step,accelerates interfacial electron/Li-transfer rate during cycling,thereby accelerating dual-directional sulfur catalytic conversion rate in LSBs.Consequently,the S/Co_(0.1)Mo_(0.9)P/MXene cathode attains a large initial capacity of 1357 mAh g^(-1)at 0.2 C and a 500-cycle long stability(0.071%decay rate per cycle)at 0.5 C.Impressively,the high-loading S/Co_(0.1)Mo_(0.9)P/MXene cathode(sulfur loading:5.2 mg cm^(-2))also presents a remarkable initial areal capacity(6.5 mAh cm^(-2))with superior cycling stability under lean electrolyte(4.8μL mg_(sulfur)^(-1))conditions,and its Li-S pouch cell delivers a high capacity of 1029.4 mAh g^(-1).This study enhances the comprehension of catalyst effect in Li-S chemistry and provides important guidelines for designing effective dual-directional Li-S catalysts.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA 0400301)the National Key R&D Program of China(No.2022YFB4002000)+3 种基金the National Natural Science Foundation of China(No.22232004)the Instrument Developing Project of the Chinese Academy of Sciencesthe Jilin Province Development and Reform Commission Program(2023C032-6)the Jilin Province Science and Technology Development Program(No.20240302002ZD,20240101019JC and 20210502002ZP)for financial support。
文摘The development of robust and active oxygen evolution reaction(OER)electrocatalysts is urgently desirable for the widespread implementation of proton exchange membrane water electrolyzers(PEMWE),yet remains a critical challenge.We propose a catalyst named U-IrRuO_(x)@IrRu(where“U”denotes“ultrathin”),which features a spontaneously formed amorphous oxide shell that synergistically optimizes the electronic structure and corrosion resistance.Combined experimental and theoretical studies reveal that the oxyphilic Ru-induced electronic modulation weakens Ir-O binding strength,thereby accelerating the rate-determining step of ^(*)OOH formation.In addition,the metallic alloy core functions as an electron reservoir,suppressing excessive oxidation of active sites while ensuring high conductivity.Due to these attributes,the U-IrRuO_(x)@IrRu demonstrates a low overpotential of 230 mV at 10 mA cm^(-2),outperforming commercial IrO_(2)(CM)by 65 mV.When integrated into a PEMWE with an ultra-low Ir loading of 0.25 mg_(Ir)cm^(-2),it delivers an industrial current density of 2 A cm^(-2)at 1.74 V and 3 A cm^(-2)at 1.836 V,surpassing the U.S.Department of Energy(DOE)2025 target.More impressively,the U-IrRuOx@IrRubased electrolyzer can stably operate for over 550 h,with an extremely low decay rate of 7.52μV h^(-1),corresponding to a predicted lifespan of 23,000 h with 90%performance retention.
文摘BACKGROUND Renal cell carcinoma(RCC)is treated with surgical resection as the gold standard,as it is notoriously resistant to systemic therapy.Advancements with targeted therapies contribute to declining mortality,but metastatic RCC(mRCC)survival remains poor.One possible factor is treatment at academic centers,which employ advanced providers and novel therapies.This study compared outcomes of mRCC in patients treated at academic/research facilities compared to those treated at non-academic centers.AIM To compare survival outcomes of mRCC and their various etiologies between academic and non-academic centers.METHODS The National Cancer Database was used to identify mRCC patients including all histology subtypes and stage IV disease.Descriptive statistics and Kaplan-Meier curves measured survival outcomes for user file facility types sorted into a binary academic/research and non-academic research variable.Multivariate logistic regression and Cox proportional hazard testing generated odds ratio and hazard ratio.Data was analyzed using Statistical Package for the Social Sciences version 29.0 using a significance level of P<0.05.RESULTS Overall,academic facility patients experienced greater 5-year and 10-year overall survival than non-academic facility patients.Treatment at non-academic facilities was associated with increased odds of death that persisted even after controlling for age,tumor size,sex,and distance traveled to treatment center.In comparison,nonacademic facility patients also experienced greater risk of hazard.CONCLUSION Patients with mRCC treated at academic/research facilities experienced increased survival compared to patients treated at non-academic facilities,were more likely to be younger,carry private insurance,and come from a large metropolitan area.They also were significantly more likely to receive surgery and adjuvant immunotherapy.
基金Major Program of National Social Science Foundation of China,No.21&ZD107。
文摘Data centers operate as physical digital infrastructure for generating,storing,computing,transmitting,and utilizing massive data and information,constituting the backbone of the flourishing digital economy across the world.Given the lack of a consistent analysis for studying the locational factors of data centers and empirical deficiencies in longitudinal investigations on spatial dynamics of heterogeneous data centers,this paper develops a comprehensive analytical framework to examine the dynamic geographies and locational factors of techno-environmentally heterogeneous data centers across Chinese cities in the period of 2006–2021.First,we develop a“supply-demand-environment trinity”analytical framework as well as an accompanying evaluation indicator system with Chinese characteristics.Second,the dynamic geographies of data centers in Chinese cities over the last decades are characterized as spatial polarization in economically leading urban agglomerations alongside persistent interregional gaps across eastern,central,and western regions.Data centers present dual spatial expansion trajectories featuring outward radiation from eastern core urban agglomerations to adjacent peripheries and leapfrog diffusion to strategic central and western digital infrastructural hubs.Third,it is empirically verified that data center construction in Chinese cities over the last decades has been jointly influenced by supply-,demand-,and environment-side locational factors,echoing the efficacy of the trinity analytical framework.Overall,our findings demonstrate the temporal variance,contextual contingency,and attribute-based differentiation of locational factors underlying techno-environmentally heterogeneous data centers in Chinese cities.
文摘The rapidly growing seaweed farming contributes to food,feed,biofuel,and biochemicals,with Indonesia being the largest exporter of raw seaweed(53.35%)but low in carrageenan derivative products(4.49%).Sustainable farming supports SDG 13 and SDG 14 through emission reduction,marine ecosystem conservation,and increased biodiversity.However,its supply chain faces challenges in raw material availability,such as fluctuating harvests,inconsistent quality,limited logistics infrastructure,and market price volatility.Therefore,good environmental management is needed to optimize raw materials in carrageenan production through resource efficiency,environmentally friendly products,environmental regulations,and market and stakeholder awareness.This study identifies factors in the environment-based supply chain that influence the development of carrageenan production centers and analyzes their ecological impacts using quantitative SEM analysis.SEM analysis reveals that resource efficiency,waste management,environmental regulations,and stakeholder awareness and commitment are the main influencing factors.shows significant factors including raw material efficiency,waste management,and environmental regulations.Environmentally based supply chain integration for the development of carrageenan production center areas can be done by;focusing on sustainability and minimal environmental impact,support for achieving SDG 12,13,and 14,strategies for sustainable raw material management,circular economy,sustainability certification,renewable energy and environmentally friendly technology,and stakeholder collaboration and awareness.
基金supported by the National Natural Science Foundation of China(No.22072183)the Natural Science Foundation of Hunan Province,China(No.2022JJ30690)the High Performance Computing Center of Central South University.
文摘Serpentine structured Co_(3)Si_(2)O_(5)(OH)_(4) is inexpensive,chemically stable,and electrochemically active in oxygen evolution reactions(OER).However,the OER activity of Co_(3)Si_(2)O_(5)(OH)_(4) materials is still unfavorable due to the low active sites.Here,Mn^(2+)-doped Co_(3)Si_(2)O_(5)(OH)_(4) serpentine nanosheets with tuned d-band centers are achieved for efficient oxygen evolution in alkaline and neutral electrolytes.The Co_(x)Mn_(3−x)Si_(2)O_(5)(OH)_(4) serpentine nanosheets are synthesized by a simple hydrothermal method.The optimized Co_(2.4)Mn_(0.6)Si_(2)O_(5)(OH)_(4) serpentine nanosheets showed favorable OER overpotentials as well as stable durability in KOH solution and phosphate buffer solution,which were superior to most of the Co-based and Mn-based OER electrocatalysts.The in situ Raman spectroscopy shows that the materials are kept well in the electrochemical OER environments.Further density functional theory shows that the d-band center of Co_(x)Mn_(3−x)Si_(2)O_(5)(OH)_(4) serpentine nanosheets is shifted more upward in comparison with pristine Co_(3)Si_(2)O_(5)(OH)_(4).The changes in the d-band center increase the adsorption of intermediates,optimize the reaction steps,and lower the energy barriers of the OER.That is the main reason for the OER enhancement Mn^(2+)-doped Co_(3)Si_(2)O_(5)(OH)_(4).This work gives an efficient strategy to design cheap and stable electrocatalytic materials for OER in a broad pH environment.
基金supported in part by the National Natural Science Foundation of China under Grant 52177082in part by the Beijing Nova Program under Grant 20220484007.
文摘With the advent of the digital economy,there has been a rapid proliferation of small-scale Internet data centers(SIDCs).By leveraging their spatiotemporal load regulation potential through data workload balancing,aggregated SIDCs have emerged as promising demand response(DR)resources for future power distribution systems.This paper presents an innovative framework for assessing capacity value(CV)by aggregating SIDCs participating in DR programs(SIDC-DR).Initially,we delineate the concept of CV tailored for aggregated SIDC scenarios and establish a metric for the assessment.Considering the effects of the data load dynamics,equipment constraints,and user behavior,we developed a sophisticated DR model for aggregated SIDCs using a data network aggregation method.Unlike existing studies,the proposed model captures the uncertainties associated with end tenant decisions to opt into an SIDC-DR program by utilizing a novel uncertainty modeling approach called Z-number formulation.This approach accounts for both the uncertainty in user participation intentions and the reliability of basic information during the DR process,enabling high-resolution profiling of the SIDC-DR potential in the CV evaluation.Simulation results from numerical studies conducted on a modified IEEE-33 node distribution system confirmed the effectiveness of the proposed approach and highlighted the potential benefits of SIDC-DR utilization in the efficient operation of future power systems.
基金the National Natural Science Foundation of China(No.22072020)the Science Foundation of the Fujian Province(Nos.2022HZ027004,2022L3082,2021L3003,and 2019 J01203).
文摘The enantioselective separation of racemate,particularly those containing C(sp^(3))-H bonds knowns for their high bond dissociation energies and significant polarity,presents a significant challenge in pharmaceutical synthesis.Recent advances have witnessed the fusion of photocatalysis with hydrogen atom transfer(HAT)methodologies,marking a notable trend in synthesis of chiral molecules.This technique uses the excitation of a catalyst to activate substrates,enabling the selective isomerization of chiral centers containing C(sp^(3))configurations.This process distinctively facilitates the direct activation of the C(sp^(3))-H bond in targeted reagents.This review systematically discusses the photocatalytic isomerization of various chiral molecule featuring C(sp^(3))-H centers,capable of undergoing deracemization through two primary HAT mechanisms:direct and indirect pathways.From the perspective of synthetic organic chemistry,this field has progressed towards the development of isomerization strategies for molecules that incorporate an activating group at theα-position adjacent to the C(sp^(3))chiral center.Moreover,it covers methodologies applicable to molecules characterized by specific C-C and C-S bond configurations.The integration of photocatalysis with HAT technology thus provides valuable strategies for the synthesis of enantiopure compounds with enhanced selectivity and efficiency.
基金supported by the Scientific&Technical Project of the State Grid(5700--202490228A--1--1-ZN).
文摘The rapid advancement of artificial intelligence(AI)has significantly increased the computational load on data centers.AI-related computational activities consume considerable electricity and result in substantial carbon emissions.To mitigate these emissions,future data centers should be strategically planned and operated to fully utilize renewable energy resources while meeting growing computational demands.This paper aims to investigate how much carbon emission reduction can be achieved by using a carbonoriented demand response to guide the optimal planning and operation of data centers.A carbon-oriented data center planning model is proposed that considers the carbon-oriented demand response of the AI load.In the planning model,future operation simulations comprehensively coordinate the temporal‒spatial flexibility of computational loads and the quality of service(QoS).An empirical study based on the proposed models is conducted on real-world data from China.The results from the empirical analysis show that newly constructed data centers are recommended to be built in Gansu Province,Ningxia Hui Autonomous Region,Sichuan Province,Inner Mongolia Autonomous Region,and Qinghai Province,accounting for 57%of the total national increase in server capacity.33%of the computational load from Eastern China should be transferred to the West,which could reduce the overall load carbon emissions by 26%.
文摘In this paper we shall extend the paper [1] to a separate Taylor's Theorem with respect to a lot of centers, namely Newton's Theorem Of a lot of centers. From it we obtain the analogous results in the paper [2]. namely an interpolation formula of the difference of higher order. Finally we give their applications.
文摘A survey of language training centers(LTCs)in Dalian,China was conducted,to ascertain the strengths and weaknesses,or the differentiating factors,of such centers.The survey was undertaken to understand the current landscape of after-school institutes in the region,particularly those that offer training in English as a second/foreign language.The information uncovered by the research is considered beneficial not only to entrepreneurs who may wish to be involved in this industry,but also to college English majors who may wish to teach at an LTC.
基金Under the auspices of the National Natural Science Foundation of China(No.41201107)the Fundamental Research Funds for the Central Universities(No.2015KJJCB30)
文摘The increasing globalization of the Chinese economy has been enabled by both Chinese financial institutions operating globally as well as international firms operating within China. In geographical terms, this has been organized through a number of strategic cities serving as gateways for the exchange of financial functions, products and practices between China and the global economy. Drawing on location data of financial service firms in China listed on stock exchanges in Shenzhen, Shanghai and Hong Kong, this paper shows that Chinese financial firms are expanding globally and how Chinese financial centers are positioned and connected in the urban networks shaped by these financial service firms. It is found that Hong Kong, China, holds strategic positions in the integration of Chinese cities into global financial center networks, and that establishing a foothold in global financial centers such as New York and London has been a priority for Chinese financial institutions. The increasing capital flows directed by Chinese financial institutionssuggests a shifting global financial geography, with numerous Chinese cities playing increasingly important roles within global financial center networks.
