Thermal energy storage(TES)is a key technology for renewable energy utilization and the improvement of the energy efficiency of heat processes.Sectors include industrial process heat and conventional and renewable pow...Thermal energy storage(TES)is a key technology for renewable energy utilization and the improvement of the energy efficiency of heat processes.Sectors include industrial process heat and conventional and renewable power generation.TES systems correct the mismatch between supply and demand of thermal energy.In the medium to high temperature range(100~1000℃),only limited storage technology is commercially available and a strong effort is needed to develop a range of storage technologies which are efficient and economical for the very specific requirements of the different application sectors.At the DLR's Institute of Technical Thermodynamics,the complete spectrum of high temperature storage technologies,from various types of sensible over latent heat to thermochemical heat storages are being developed.Different concepts are proposed depending on the heat transfer fluid(synthetic oil,water/steam,molten salt,air)and the required temperature range.The aim is the development of cost effective,efficient and reliable thermal storage systems.Research focuses on characterization of storage materials,enhancement of internal heat transfer,design of innovative storage concepts and modelling of storage components and systems.Demonstration of the storage technology takes place from laboratory scale to field testing(5 kW^1 MW).The paper gives an overview on DLR's current developments.展开更多
BACKGROUND A man experienced multiple episodes of macroscopic hematuria following nocturnal exercise.Urinary stones and tumors were considered the two most likely causes.The patient had two hobbies:Consuming health ca...BACKGROUND A man experienced multiple episodes of macroscopic hematuria following nocturnal exercise.Urinary stones and tumors were considered the two most likely causes.The patient had two hobbies:Consuming health care products in large quantities and engaging in late-night running.CASE SUMMARY Health care products contain a large amount of calcium phosphate,and we hypothesize that this could induce the formation of small phosphate stones.After exercise,the urinary system is abraded,resulting in bleeding.The patient was advised to stop using the health care products.Consequently,the aforementioned symptoms disappeared immediately.However,the patient resumed the above two habits one year later;correspondingly,the macroscopic hematuria reap-peared.CONCLUSION This finding further confirmed the above inference and allowed for a new avenue to determine the cause of the patient’s hematuria.展开更多
BACKGROUND Research on gastrointestinal mucosal adenocarcinoma(GMA)is limited and controversial,and there is no reference tool for predicting postoperative survival.AIM To investigate the prognosis of GMA and develop ...BACKGROUND Research on gastrointestinal mucosal adenocarcinoma(GMA)is limited and controversial,and there is no reference tool for predicting postoperative survival.AIM To investigate the prognosis of GMA and develop predictive model.METHODS From the Surveillance,Epidemiology,and End Results database,we collected clinical information on patients with GMA.After random sampling,the patients were divided into the discovery(70%of the total,for model training),validation(20%,for model evaluation),and completely blind test cohorts(10%,for further model evaluation).The main assessment metric was the area under the receiver operating characteristic curve(AUC).All collected clinical features were used for Cox proportional hazard regression analysis to determine factors influencing GMA’s prognosis.RESULTS This model had an AUC of 0.7433[95% confidence intervals(95%CI):0.7424-0.7442]in the discovery cohort,0.7244(GMA:0.7234-0.7254)in the validation cohort,and 0.7388(95%CI:0.7378-0.7398)in the test cohort.We packaged it into Windows software for doctors’use and uploaded it.Mucinous gastric adenocarcinoma had the worst prognosis,and these were protective factors of GMA:Regional nodes examined[hazard ratio(HR):0.98,95%CI:0.97-0.98,P<0.001]and chemotherapy(HR:0.62,95%CI:0.58-0.66,P<0.001).CONCLUSION The deep learning-based tool developed can accurately predict the overall survival of patients with GMA postoperatively.Combining surgery,chemotherapy,and adequate lymph node dissection during surgery can improve patient outcomes.展开更多
Titanium(Ti)alloys are widely used in high-tech fields like aerospace and biomedical engineering.Laser additive manufacturing(LAM),as an innovative technology,is the key driver for the development of Ti alloys.Despite...Titanium(Ti)alloys are widely used in high-tech fields like aerospace and biomedical engineering.Laser additive manufacturing(LAM),as an innovative technology,is the key driver for the development of Ti alloys.Despite the significant advancements in LAM of Ti alloys,there remain challenges that need further research and development efforts.To recap the potential of LAM high-performance Ti alloy,this article systematically reviews LAM Ti alloys with up-to-date information on process,materials,and properties.Several feasible solutions to advance LAM Ti alloys are reviewed,including intelligent process parameters optimization,LAM process innovation with auxiliary fields and novel Ti alloys customization for LAM.The auxiliary energy fields(e.g.thermal,acoustic,mechanical deformation and magnetic fields)can affect the melt pool dynamics and solidification behaviour during LAM of Ti alloys,altering microstructures and mechanical performances.Different kinds of novel Ti alloys customized for LAM,like peritecticα-Ti,eutectoid(α+β)-Ti,hybrid(α+β)-Ti,isomorphousβ-Ti and eutecticβ-Ti alloys are reviewed in detail.Furthermore,machine learning in accelerating the LAM process optimization and new materials development is also outlooked.This review summarizes the material properties and performance envelops and benchmarks the research achievements in LAM of Ti alloys.In addition,the perspectives and further trends in LAM of Ti alloys are also highlighted.展开更多
Repairs of corroded high-pressure pipelines are essential for fluids transportation under high pressure.One of the methods used in their repairs is the use of layered composites.The composite used must have the necess...Repairs of corroded high-pressure pipelines are essential for fluids transportation under high pressure.One of the methods used in their repairs is the use of layered composites.The composite used must have the necessary strength.Therefore,the experiments and analytical solutions presented in this paper are performed according to the relevant standards and codes,including ASME PCC-2,ASME B31.8S,ASME B31.4,ISO 24817 and ASME B31.G.In addition,the experimental tests are replicated numerically using the finite element method.Setting the strain gauges at different distances from the defect location,can reduce the nonlinear effects,deformation,and fluctuations due to the high pressure.The direct relationship between the depth of an axial defect and the stress concentration is observed at the inner side edges of the defect.Composite reparation reduces the non-linearities related to the sharp variation of the geometry and a more reliable numerical simulation could be performed.展开更多
Objective:To validate the 8 th edition of the American Joint Committee on Cancer(AJCC)staging system for pancreatic ductal adenocarcinoma(PDAC)in a Chinese cohort of radically resected patients and to develop a refine...Objective:To validate the 8 th edition of the American Joint Committee on Cancer(AJCC)staging system for pancreatic ductal adenocarcinoma(PDAC)in a Chinese cohort of radically resected patients and to develop a refined staging system for PDAC.Methods:Data were collected from the China Pancreas Data Center(CPDC)for patients with resected PDAC in 2016 and 2017,and cancer-specific survival(CSS)was evaluated using the Kaplan-Meier method and log-rank test.Univariate and multivariate analyses based on Cox regression were performed to identify prognostic factors.The recursive partitioning analysis(RPA),Kaplan-Meier method,and log-rank test were performed on the training dataset to generate a proposed modification for the 8 th TNM staging system utilizing the preoperative carbohydrate antigen(CA)19-9 level.Validation was performed for both staging systems in the validation cohort.Results:A total of 1,676 PDAC patients were retrieved,and the median CSS was significantly different between the 8 th TNM groupings,with no significant difference in survival between stage IB and IIA.The analysis of T and N stages demonstrated a better prognostic value in the N category.Multivariate analysis showed that the preoperative serum CA19-9 level was the strongest prognostic indicator among all the independent risk factors.All patients with CA19-9>500 U/mL had similar survival,and we proposed a new staging system by combining IB and IIA and stratifying all patients with high CA19-9 into stage III.The modified staging system had a better performance for predicting CSS than the 8 th AJCC staging scheme.Conclusions:The 8 th AJCC staging system for PDAC is suitable for a Chinese cohort of resected patients,and the N category has a better prognostic value than the T category.Our modified staging system has superior accuracy in predicting survival than the 8 th AJCC TNM staging system.展开更多
Proton conducting ceramic cells(PCCs)are an attractive emerging technology operating in the intermediate temperature range of 500 to 700℃.In this work,we evaluate the production of hydrogen at intermediate temperatur...Proton conducting ceramic cells(PCCs)are an attractive emerging technology operating in the intermediate temperature range of 500 to 700℃.In this work,we evaluate the production of hydrogen at intermediate temperatures by proton conducting ceramic cell electrolysis(PCCEL).We demonstrate a highperformance steam electrolysis owing to a composite positrode based on BaGd_(0.8)La_(0.2)Co_(2)O_(6-δ)(BGLC1082)and BaZr0.5Ce0.4Y0.1O3-δ(BZCY541).The high reliability of PCCEL is demonstrated for 1680 h at a current density as high as-0.8 A cm^(-2)close to the thermoneutral cell voltage at 600℃.The electrolysis cell showed a specific energy consumption ranging from 54 to 66 kW h kg^(-1)that is comparable to state-of-the-art low temperature electrolysis technologies,while showing hydrogen production rates systematically higher than commercial solid oxide ceramic cells(SOCs).Compared to SOCs,the results verified the higher performances of PCCs at the relevant operating temperatures,due to the lower activation energy for proton transfer comparing with oxygen ion conduction.However,because of the p-type electronic conduction in protonic ceramics,the energy conversion rate of PCCs is relatively lower in steam electrolysis.The faradaic efficiency of the PCC in electrolysis mode can be increased at lower operating temperatures and in endothermic conditions,making PCCEL a technology of choice to valorize high temperature waste heat from industrial processes into hydrogen.To increase the faradaic efficiency by optimizing the materials,the cell design,or the operating strategy is a key challenge to address for future developments of PCCEL in order to achieve even more superior techno-economic merits.展开更多
With the development of artificial intelligence,remote sensing scene interpretation task has attracted extensive attention,which mainly includes scene classification,target detection,hyperspectral classification,and m...With the development of artificial intelligence,remote sensing scene interpretation task has attracted extensive attention,which mainly includes scene classification,target detection,hyperspectral classification,and multi‐modal analysis.The remote sensing scene interpretation has effectively promoted the development of the Earth observation field.It was the intention for this Special Issue to serve as a platform for the publication of the most recent research concepts from remote sensing image.展开更多
BACKGROUND As left bundle branch pacing(LBBP)is more like physiological pacing,LBBP has emerged as a novel pacing strategy that uses the native conduction system to improve ventricular synchronization with stable paci...BACKGROUND As left bundle branch pacing(LBBP)is more like physiological pacing,LBBP has emerged as a novel pacing strategy that uses the native conduction system to improve ventricular synchronization with stable pacing parameters.LBBP has been revealed associated with a significantly reduced risk of new-onset atrial fibrillation and heart failure compared with conventional permanent pacemaker implantation.CASE SUMMARY A 64-year-old man was admitted with a 24-h history of chest distress and shortness of breath,which continued unabated.The patient had no symptoms of chest pain,dizziness,syncope,nausea nor vomiting.There were no abnormalities found in routine examinations after admission.Twelve-lead electrocardiogram presented a result of 2:1 atrioventricular block.Coronary angiography was performed the next day and no abnormality was found.Finally,the patient agreed to received LBBP and signed the informed consent.During the process of withdrawing the Medtronic Model 3830 lead into sheath,we found the lead helix was wrapped around the chordae tendineae of the septal valve of tricuspid.Attempts to rotate the 3830 lead failed to release the lead helix from the chordae tendineae,and ultimately we used radiofrequency ablation to ablate the wrapped chordae tendineae.CONCLUSION Radiofrequency ablation effectively solved this problem without complications.It is an effective and reliable method to resolve lead winding chordae.展开更多
This paper presents a comprehensive experimental study on the effect of extreme waves on a LNG carrier.The LNG carrier model was equipped with a variety of sensors to measure motions,green water height on deck as well...This paper presents a comprehensive experimental study on the effect of extreme waves on a LNG carrier.The LNG carrier model was equipped with a variety of sensors to measure motions,green water height on deck as well as local and global loads.Experiments in transient wave packets provided the general performance in waves in terms of response amplitude operators and were accompanied by tests in regular waves with two different wave steepness.These tests allowed detailed insights into the nonlinear behavior of the vertical wave bending moment in steep waves showing that green water on deck can contribute to a decrease of vertical wave bending moment.Afterwards,systematic model tests in irregular waves were performed to provide the basis for statistical analysis.It is shown that the generalized extreme value distribution model is suitable for the estimation of the extreme peak values of motions and loads.Finally,model tests in tailored extreme wave sequences were conducted comparing the results with the statistical analysis.For this purpose,analytical breather solutions of the nonlinear Schrödinger equation were applied to generate tailored extreme waves of certain critical wave lengths in terms of ship response.Besides these design extreme waves,the LGN carrier was also investigated in the model scale reproduction of the real-world Draupner wave.By comparing the motions,vertical wave bending moment,green water column and slamming pressures it is concluded that the breather solutions are a powerful and efficient tool for the generation of design extreme waves of certain critical wave lengths for wave/structure investigations on different subjects.展开更多
Tianwen-1 is China's first independent interplanetary exploration mission,targeting Mars,and includes orbiting,landing,and rover phases.Similar to previous Mars missions,the Tianwen-1 orbiter was designed for pola...Tianwen-1 is China's first independent interplanetary exploration mission,targeting Mars,and includes orbiting,landing,and rover phases.Similar to previous Mars missions,the Tianwen-1 orbiter was designed for polar orbits during the scientific mission period but has an exceptional eccentricity of approximately 0.59.We provide the first independent eight-degree Martian gravity field model in this paper,which was developed exclusively by a team working in China with our independent software as well,based on about two months of radiometric Doppler and range data from only the Tianwen-1 mission.This model is independent from the models created by the groups at NASA Jet Propulsion Laboratory and Goddard Space Flight Center in the United States,as well as the Centre National d'Etudes Spatiales in France.Furthermore,in order to optimize the engineering and scientific benefits,we proposed a number of potential orbits for the extended Tianwen-1 mission.In order to solve a higher-degree independent Mars gravity field model,the viability of modifying the perigee height was investigated,with the priority considerations of fuel savings and implementation hazards being controlled.展开更多
To the Editor:Hematopoietic cell transplantation(HCT)is a vital modality to cure severe hematological disorders.[1]Global or regional summarized data of HCT are annually reported by the Chinese Blood and Marrow Transp...To the Editor:Hematopoietic cell transplantation(HCT)is a vital modality to cure severe hematological disorders.[1]Global or regional summarized data of HCT are annually reported by the Chinese Blood and Marrow Transplantation Registry Group(CBMTRG),European Society for Blood and Marrow Transplantation(EBMT)and Center for International Blood and Marrow Transplant Research(CIBMTR).It is shown that the number of transplants is continuously increasing,particularly in China in recent years.[2]Since the donor accessibility is significantly addressed by the well-established protocol of haplo-identical HCT(haplo-HCT).展开更多
Concentrated solar power(CSP)plants with thermal energy storage(TES)system are emerging as one kind of the most promising power plants in the future renewable energy system,since they can supply dispatchable and low-c...Concentrated solar power(CSP)plants with thermal energy storage(TES)system are emerging as one kind of the most promising power plants in the future renewable energy system,since they can supply dispatchable and low-cost electricity with abundant but intermittent solar energy.In order to significantly reduce the levelized cost of electricity(LCOE)of the present commercial CSP plants,the next generation CSP technology with higher process temperature and energy efficiency is being developed.The TES system in the next generation CSP plants works with new TES materials at higher temperatures(>565℃)compared to that with the commercial nitrate salt mixtures.This paper reviews recent progressin research and development of the next generation CSP and TES technology.Emphasis is given on theadvanced'TES technology based on molten chloride salt mixtures such as MgCl_(2)/NaCl/KCl which hassimilar thermo-physical properties as the commercial nitrate salt mixtures,higher thermal stability(>800℃),and lower costs(<0.35USD·kg^(-1)).Recent progress in the selection/optimization of chloridesalts,determination of molten chloride salt properties,and corrosion control of construction materials(eg.,alloys)in molten chlorides is reviewed.展开更多
AIM To explore the association between Helicobacter pylori(H. pylori) infection and obesity/weight gain in a Chinese population.METHODS Our primary outcome was the change in body mass index(BMI). The generalized linea...AIM To explore the association between Helicobacter pylori(H. pylori) infection and obesity/weight gain in a Chinese population.METHODS Our primary outcome was the change in body mass index(BMI). The generalized linear models were used to explore the association between H. pylori infection and the change of BMI, and the logistic regression models were used to explore the association between H. pylori infection and obesity.RESULTS A total of 3039 subjects were recruited and analyzed, of which 12.8% were obese. The prevalence of H. pylori infection was 53.9%(1639/3039) overall and 54.6%(212/388) in the obese subjects. The change of BMI in the H. pylori(+) group was not significantly higher than that in the H. pylori(-) group after adjustment for potential confounding factors [RR = 0.988, 95%CI:0.924-1.057, P = 0.729]. The prevalence of obesity decreased 1.1% in the H. pylori(+) group and 0.5% in the H. pylori(-) group. The RR of H. pylori infection for obesity was 0.831(95%CI: 0.577-1.197, P = 0.321) after the adjustment.CONCLUSION H. pylori infection was not associated with overweight/obesity observed from the retrospective study in this Chinese population.展开更多
The analysis centers of the Multi-GNSS Pilot Project of the International GNSS Service provide orbit and clock products for the global navigation satellite systems(GNSSs)Global Positioning System(GPS),GLONASS,Galileo,...The analysis centers of the Multi-GNSS Pilot Project of the International GNSS Service provide orbit and clock products for the global navigation satellite systems(GNSSs)Global Positioning System(GPS),GLONASS,Galileo,and BeiDou,as well as for the Japanese regional Quasi-Zenith Satellite System(QZSS).Due to improved solar radiation pressure modeling and other more sophisticated models,the consistency of these products has improved in recent years.The current orbit consistency between different analysis centers is on the level of a few centimeters for GPS,around one decimeter for GLONASS and Galileo,a few decimeters for BeiDou-2,and several decimeters for QZSS.The clock consistency is about 2 cm for GPS,5 cm for GLONASS and Galileo,and 10 cm for BeiDou-2.In terms of carrier phase modeling error for precise point positioning,the various products exhibit consistencies of 2–3 cm for GPS,6–14 cm for GLONASS,3–10 cm for Galileo,and 10–17 cm for BeiDou-2.展开更多
A grasping force control strategy is proposed in order to complete various fine manipulations by using anthropomorphic prosthetic hand.The position-based impedance control and force-tracking impedance control are used...A grasping force control strategy is proposed in order to complete various fine manipulations by using anthropomorphic prosthetic hand.The position-based impedance control and force-tracking impedance control are used in free and constraint spaces,respectively.The fuzzy observer is adopted in transition in order to switch control mode.Two control modes use one position-based impedance controller.In order to achieve grasping force track,reference force is added to the impedance controller in the constraint space.Trajectory tracking in free space and torque tracking in constrained space are realized,and reliability of mode switch and stability of system are achieved.An adaptive sliding mode friction compensation method is proposed.This method makes use of terminal sliding mode idea to design sliding mode function,which makes the tracking error converge to zero in finite time and avoids the problem of conventional sliding surface that tracking error cannot converge to zero.Based on the characteristic of the exponential form friction,the sliding mode control law including the estimation of friction parameter is obtained through terminal sliding mode idea,and the online parameter update laws are obtained based on Lyapunov stability theorem.The experiments on the HIT Prosthetic Hand IV are carried out to evaluate the grasping force control strategy,and the experiment results verify the effectiveness of this control strategy.展开更多
基金funded through the basic DLR funding of the Helmholtz AssociationSpecific support for several projects was given by the German Federal Ministry of Economics and Technology and the German Federal Ministry for the Environment,Nature Conservation and Nuclear SafetyThe CellFlux project is funded by E.ON AG as part of the International Research Initiative.Responsibility for the content of this publication lieswith the authors
文摘Thermal energy storage(TES)is a key technology for renewable energy utilization and the improvement of the energy efficiency of heat processes.Sectors include industrial process heat and conventional and renewable power generation.TES systems correct the mismatch between supply and demand of thermal energy.In the medium to high temperature range(100~1000℃),only limited storage technology is commercially available and a strong effort is needed to develop a range of storage technologies which are efficient and economical for the very specific requirements of the different application sectors.At the DLR's Institute of Technical Thermodynamics,the complete spectrum of high temperature storage technologies,from various types of sensible over latent heat to thermochemical heat storages are being developed.Different concepts are proposed depending on the heat transfer fluid(synthetic oil,water/steam,molten salt,air)and the required temperature range.The aim is the development of cost effective,efficient and reliable thermal storage systems.Research focuses on characterization of storage materials,enhancement of internal heat transfer,design of innovative storage concepts and modelling of storage components and systems.Demonstration of the storage technology takes place from laboratory scale to field testing(5 kW^1 MW).The paper gives an overview on DLR's current developments.
文摘BACKGROUND A man experienced multiple episodes of macroscopic hematuria following nocturnal exercise.Urinary stones and tumors were considered the two most likely causes.The patient had two hobbies:Consuming health care products in large quantities and engaging in late-night running.CASE SUMMARY Health care products contain a large amount of calcium phosphate,and we hypothesize that this could induce the formation of small phosphate stones.After exercise,the urinary system is abraded,resulting in bleeding.The patient was advised to stop using the health care products.Consequently,the aforementioned symptoms disappeared immediately.However,the patient resumed the above two habits one year later;correspondingly,the macroscopic hematuria reap-peared.CONCLUSION This finding further confirmed the above inference and allowed for a new avenue to determine the cause of the patient’s hematuria.
文摘BACKGROUND Research on gastrointestinal mucosal adenocarcinoma(GMA)is limited and controversial,and there is no reference tool for predicting postoperative survival.AIM To investigate the prognosis of GMA and develop predictive model.METHODS From the Surveillance,Epidemiology,and End Results database,we collected clinical information on patients with GMA.After random sampling,the patients were divided into the discovery(70%of the total,for model training),validation(20%,for model evaluation),and completely blind test cohorts(10%,for further model evaluation).The main assessment metric was the area under the receiver operating characteristic curve(AUC).All collected clinical features were used for Cox proportional hazard regression analysis to determine factors influencing GMA’s prognosis.RESULTS This model had an AUC of 0.7433[95% confidence intervals(95%CI):0.7424-0.7442]in the discovery cohort,0.7244(GMA:0.7234-0.7254)in the validation cohort,and 0.7388(95%CI:0.7378-0.7398)in the test cohort.We packaged it into Windows software for doctors’use and uploaded it.Mucinous gastric adenocarcinoma had the worst prognosis,and these were protective factors of GMA:Regional nodes examined[hazard ratio(HR):0.98,95%CI:0.97-0.98,P<0.001]and chemotherapy(HR:0.62,95%CI:0.58-0.66,P<0.001).CONCLUSION The deep learning-based tool developed can accurately predict the overall survival of patients with GMA postoperatively.Combining surgery,chemotherapy,and adequate lymph node dissection during surgery can improve patient outcomes.
基金financially supported by the Young Individual Research Grants(Grant No:M22K3c0097)Singapore RIE 2025 plan and Singapore Aerospace Programme Cycle 16(Grant No:M2215a0073)led by C Tan+2 种基金supported by the Singapore A*STAR Career Development Funds(Grant No:C210812047)the National Natural Science Foundation of China(52174361 and 52374385)the support by US NSF DMR-2104933。
文摘Titanium(Ti)alloys are widely used in high-tech fields like aerospace and biomedical engineering.Laser additive manufacturing(LAM),as an innovative technology,is the key driver for the development of Ti alloys.Despite the significant advancements in LAM of Ti alloys,there remain challenges that need further research and development efforts.To recap the potential of LAM high-performance Ti alloy,this article systematically reviews LAM Ti alloys with up-to-date information on process,materials,and properties.Several feasible solutions to advance LAM Ti alloys are reviewed,including intelligent process parameters optimization,LAM process innovation with auxiliary fields and novel Ti alloys customization for LAM.The auxiliary energy fields(e.g.thermal,acoustic,mechanical deformation and magnetic fields)can affect the melt pool dynamics and solidification behaviour during LAM of Ti alloys,altering microstructures and mechanical performances.Different kinds of novel Ti alloys customized for LAM,like peritecticα-Ti,eutectoid(α+β)-Ti,hybrid(α+β)-Ti,isomorphousβ-Ti and eutecticβ-Ti alloys are reviewed in detail.Furthermore,machine learning in accelerating the LAM process optimization and new materials development is also outlooked.This review summarizes the material properties and performance envelops and benchmarks the research achievements in LAM of Ti alloys.In addition,the perspectives and further trends in LAM of Ti alloys are also highlighted.
文摘Repairs of corroded high-pressure pipelines are essential for fluids transportation under high pressure.One of the methods used in their repairs is the use of layered composites.The composite used must have the necessary strength.Therefore,the experiments and analytical solutions presented in this paper are performed according to the relevant standards and codes,including ASME PCC-2,ASME B31.8S,ASME B31.4,ISO 24817 and ASME B31.G.In addition,the experimental tests are replicated numerically using the finite element method.Setting the strain gauges at different distances from the defect location,can reduce the nonlinear effects,deformation,and fluctuations due to the high pressure.The direct relationship between the depth of an axial defect and the stress concentration is observed at the inner side edges of the defect.Composite reparation reduces the non-linearities related to the sharp variation of the geometry and a more reliable numerical simulation could be performed.
基金supported by grants from the National Natural Science Foundation of China(No.81672353 and 81871954)。
文摘Objective:To validate the 8 th edition of the American Joint Committee on Cancer(AJCC)staging system for pancreatic ductal adenocarcinoma(PDAC)in a Chinese cohort of radically resected patients and to develop a refined staging system for PDAC.Methods:Data were collected from the China Pancreas Data Center(CPDC)for patients with resected PDAC in 2016 and 2017,and cancer-specific survival(CSS)was evaluated using the Kaplan-Meier method and log-rank test.Univariate and multivariate analyses based on Cox regression were performed to identify prognostic factors.The recursive partitioning analysis(RPA),Kaplan-Meier method,and log-rank test were performed on the training dataset to generate a proposed modification for the 8 th TNM staging system utilizing the preoperative carbohydrate antigen(CA)19-9 level.Validation was performed for both staging systems in the validation cohort.Results:A total of 1,676 PDAC patients were retrieved,and the median CSS was significantly different between the 8 th TNM groupings,with no significant difference in survival between stage IB and IIA.The analysis of T and N stages demonstrated a better prognostic value in the N category.Multivariate analysis showed that the preoperative serum CA19-9 level was the strongest prognostic indicator among all the independent risk factors.All patients with CA19-9>500 U/mL had similar survival,and we proposed a new staging system by combining IB and IIA and stratifying all patients with high CA19-9 into stage III.The modified staging system had a better performance for predicting CSS than the 8 th AJCC staging scheme.Conclusions:The 8 th AJCC staging system for PDAC is suitable for a Chinese cohort of resected patients,and the N category has a better prognostic value than the T category.Our modified staging system has superior accuracy in predicting survival than the 8 th AJCC TNM staging system.
基金The China Scholarship Council is acknowledged for the doctoral scholarship of Haoyu Zheng(201806160173)The German Federal Ministry for Education and Research is acknowledged for funding via the Project ARCADE(03SF0580A)。
文摘Proton conducting ceramic cells(PCCs)are an attractive emerging technology operating in the intermediate temperature range of 500 to 700℃.In this work,we evaluate the production of hydrogen at intermediate temperatures by proton conducting ceramic cell electrolysis(PCCEL).We demonstrate a highperformance steam electrolysis owing to a composite positrode based on BaGd_(0.8)La_(0.2)Co_(2)O_(6-δ)(BGLC1082)and BaZr0.5Ce0.4Y0.1O3-δ(BZCY541).The high reliability of PCCEL is demonstrated for 1680 h at a current density as high as-0.8 A cm^(-2)close to the thermoneutral cell voltage at 600℃.The electrolysis cell showed a specific energy consumption ranging from 54 to 66 kW h kg^(-1)that is comparable to state-of-the-art low temperature electrolysis technologies,while showing hydrogen production rates systematically higher than commercial solid oxide ceramic cells(SOCs).Compared to SOCs,the results verified the higher performances of PCCs at the relevant operating temperatures,due to the lower activation energy for proton transfer comparing with oxygen ion conduction.However,because of the p-type electronic conduction in protonic ceramics,the energy conversion rate of PCCs is relatively lower in steam electrolysis.The faradaic efficiency of the PCC in electrolysis mode can be increased at lower operating temperatures and in endothermic conditions,making PCCEL a technology of choice to valorize high temperature waste heat from industrial processes into hydrogen.To increase the faradaic efficiency by optimizing the materials,the cell design,or the operating strategy is a key challenge to address for future developments of PCCEL in order to achieve even more superior techno-economic merits.
文摘With the development of artificial intelligence,remote sensing scene interpretation task has attracted extensive attention,which mainly includes scene classification,target detection,hyperspectral classification,and multi‐modal analysis.The remote sensing scene interpretation has effectively promoted the development of the Earth observation field.It was the intention for this Special Issue to serve as a platform for the publication of the most recent research concepts from remote sensing image.
文摘BACKGROUND As left bundle branch pacing(LBBP)is more like physiological pacing,LBBP has emerged as a novel pacing strategy that uses the native conduction system to improve ventricular synchronization with stable pacing parameters.LBBP has been revealed associated with a significantly reduced risk of new-onset atrial fibrillation and heart failure compared with conventional permanent pacemaker implantation.CASE SUMMARY A 64-year-old man was admitted with a 24-h history of chest distress and shortness of breath,which continued unabated.The patient had no symptoms of chest pain,dizziness,syncope,nausea nor vomiting.There were no abnormalities found in routine examinations after admission.Twelve-lead electrocardiogram presented a result of 2:1 atrioventricular block.Coronary angiography was performed the next day and no abnormality was found.Finally,the patient agreed to received LBBP and signed the informed consent.During the process of withdrawing the Medtronic Model 3830 lead into sheath,we found the lead helix was wrapped around the chordae tendineae of the septal valve of tricuspid.Attempts to rotate the 3830 lead failed to release the lead helix from the chordae tendineae,and ultimately we used radiofrequency ablation to ablate the wrapped chordae tendineae.CONCLUSION Radiofrequency ablation effectively solved this problem without complications.It is an effective and reliable method to resolve lead winding chordae.
基金the experimental work performed during the project EXTREME SEASwhich was funded by the European Commissionunder the Grant agreement No. 234175
文摘This paper presents a comprehensive experimental study on the effect of extreme waves on a LNG carrier.The LNG carrier model was equipped with a variety of sensors to measure motions,green water height on deck as well as local and global loads.Experiments in transient wave packets provided the general performance in waves in terms of response amplitude operators and were accompanied by tests in regular waves with two different wave steepness.These tests allowed detailed insights into the nonlinear behavior of the vertical wave bending moment in steep waves showing that green water on deck can contribute to a decrease of vertical wave bending moment.Afterwards,systematic model tests in irregular waves were performed to provide the basis for statistical analysis.It is shown that the generalized extreme value distribution model is suitable for the estimation of the extreme peak values of motions and loads.Finally,model tests in tailored extreme wave sequences were conducted comparing the results with the statistical analysis.For this purpose,analytical breather solutions of the nonlinear Schrödinger equation were applied to generate tailored extreme waves of certain critical wave lengths in terms of ship response.Besides these design extreme waves,the LGN carrier was also investigated in the model scale reproduction of the real-world Draupner wave.By comparing the motions,vertical wave bending moment,green water column and slamming pressures it is concluded that the breather solutions are a powerful and efficient tool for the generation of design extreme waves of certain critical wave lengths for wave/structure investigations on different subjects.
基金supported by the National Natural Science Foundation of China(NSFC)under Nos.12203002 and 42241116Key Laboratory of Geospace Environment and Geodesy,Ministry of Education,Wuhan University under No.21-01-01funded by a DAR grant in planetology from the French Space Agency(CNES)。
文摘Tianwen-1 is China's first independent interplanetary exploration mission,targeting Mars,and includes orbiting,landing,and rover phases.Similar to previous Mars missions,the Tianwen-1 orbiter was designed for polar orbits during the scientific mission period but has an exceptional eccentricity of approximately 0.59.We provide the first independent eight-degree Martian gravity field model in this paper,which was developed exclusively by a team working in China with our independent software as well,based on about two months of radiometric Doppler and range data from only the Tianwen-1 mission.This model is independent from the models created by the groups at NASA Jet Propulsion Laboratory and Goddard Space Flight Center in the United States,as well as the Centre National d'Etudes Spatiales in France.Furthermore,in order to optimize the engineering and scientific benefits,we proposed a number of potential orbits for the extended Tianwen-1 mission.In order to solve a higher-degree independent Mars gravity field model,the viability of modifying the perigee height was investigated,with the priority considerations of fuel savings and implementation hazards being controlled.
文摘To the Editor:Hematopoietic cell transplantation(HCT)is a vital modality to cure severe hematological disorders.[1]Global or regional summarized data of HCT are annually reported by the Chinese Blood and Marrow Transplantation Registry Group(CBMTRG),European Society for Blood and Marrow Transplantation(EBMT)and Center for International Blood and Marrow Transplant Research(CIBMTR).It is shown that the number of transplants is continuously increasing,particularly in China in recent years.[2]Since the donor accessibility is significantly addressed by the well-established protocol of haplo-identical HCT(haplo-HCT).
文摘Concentrated solar power(CSP)plants with thermal energy storage(TES)system are emerging as one kind of the most promising power plants in the future renewable energy system,since they can supply dispatchable and low-cost electricity with abundant but intermittent solar energy.In order to significantly reduce the levelized cost of electricity(LCOE)of the present commercial CSP plants,the next generation CSP technology with higher process temperature and energy efficiency is being developed.The TES system in the next generation CSP plants works with new TES materials at higher temperatures(>565℃)compared to that with the commercial nitrate salt mixtures.This paper reviews recent progressin research and development of the next generation CSP and TES technology.Emphasis is given on theadvanced'TES technology based on molten chloride salt mixtures such as MgCl_(2)/NaCl/KCl which hassimilar thermo-physical properties as the commercial nitrate salt mixtures,higher thermal stability(>800℃),and lower costs(<0.35USD·kg^(-1)).Recent progress in the selection/optimization of chloridesalts,determination of molten chloride salt properties,and corrosion control of construction materials(eg.,alloys)in molten chlorides is reviewed.
基金Supported by the State Key Laboratory of Pathogen and Biosecurity(Academy of Military Medical Science)No.SKLPBS1442the Youth Talent Support Program of the School of Public Health,Peking University
文摘AIM To explore the association between Helicobacter pylori(H. pylori) infection and obesity/weight gain in a Chinese population.METHODS Our primary outcome was the change in body mass index(BMI). The generalized linear models were used to explore the association between H. pylori infection and the change of BMI, and the logistic regression models were used to explore the association between H. pylori infection and obesity.RESULTS A total of 3039 subjects were recruited and analyzed, of which 12.8% were obese. The prevalence of H. pylori infection was 53.9%(1639/3039) overall and 54.6%(212/388) in the obese subjects. The change of BMI in the H. pylori(+) group was not significantly higher than that in the H. pylori(-) group after adjustment for potential confounding factors [RR = 0.988, 95%CI:0.924-1.057, P = 0.729]. The prevalence of obesity decreased 1.1% in the H. pylori(+) group and 0.5% in the H. pylori(-) group. The RR of H. pylori infection for obesity was 0.831(95%CI: 0.577-1.197, P = 0.321) after the adjustment.CONCLUSION H. pylori infection was not associated with overweight/obesity observed from the retrospective study in this Chinese population.
基金We would like to acknowledge the efforts of the MGEX station operators,data,and analysis centers,as well as the ILRS for providing SLR normal points.
文摘The analysis centers of the Multi-GNSS Pilot Project of the International GNSS Service provide orbit and clock products for the global navigation satellite systems(GNSSs)Global Positioning System(GPS),GLONASS,Galileo,and BeiDou,as well as for the Japanese regional Quasi-Zenith Satellite System(QZSS).Due to improved solar radiation pressure modeling and other more sophisticated models,the consistency of these products has improved in recent years.The current orbit consistency between different analysis centers is on the level of a few centimeters for GPS,around one decimeter for GLONASS and Galileo,a few decimeters for BeiDou-2,and several decimeters for QZSS.The clock consistency is about 2 cm for GPS,5 cm for GLONASS and Galileo,and 10 cm for BeiDou-2.In terms of carrier phase modeling error for precise point positioning,the various products exhibit consistencies of 2–3 cm for GPS,6–14 cm for GLONASS,3–10 cm for Galileo,and 10–17 cm for BeiDou-2.
基金Project(2009AA043803) supported by the National High Technology Research and Development Program of China Project (SKLRS200901B) supported by Self-Planned Task of State Key Laboratory of Robotics and System (Harbin Institute of Technology),ChinaProject (NCET-09-0056) supported by Program for New Century Excellent Talents in Universities of China
文摘A grasping force control strategy is proposed in order to complete various fine manipulations by using anthropomorphic prosthetic hand.The position-based impedance control and force-tracking impedance control are used in free and constraint spaces,respectively.The fuzzy observer is adopted in transition in order to switch control mode.Two control modes use one position-based impedance controller.In order to achieve grasping force track,reference force is added to the impedance controller in the constraint space.Trajectory tracking in free space and torque tracking in constrained space are realized,and reliability of mode switch and stability of system are achieved.An adaptive sliding mode friction compensation method is proposed.This method makes use of terminal sliding mode idea to design sliding mode function,which makes the tracking error converge to zero in finite time and avoids the problem of conventional sliding surface that tracking error cannot converge to zero.Based on the characteristic of the exponential form friction,the sliding mode control law including the estimation of friction parameter is obtained through terminal sliding mode idea,and the online parameter update laws are obtained based on Lyapunov stability theorem.The experiments on the HIT Prosthetic Hand IV are carried out to evaluate the grasping force control strategy,and the experiment results verify the effectiveness of this control strategy.