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Influence of introducing Zr,Ti,Nb and Ce elements on externally solidified crystals and mechanical properties of high-pressure die-casting Al–Si alloy
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作者 Junjie Li Wenbo Yu +5 位作者 Zhenyu Sun Weichen Zheng Liangwei Zhang Yanling Xue Wenning Liu Shoumei Xiong 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS 2025年第1期147-153,共7页
High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress aro... High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile industry.Mg can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated die-castings.Herein,the development of non-heat treatment Al alloys is becoming the hot topic.In addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of castings.To achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of Zr,Ti,Nb,and Ce.Their influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic simulation.Our results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased porosity.Meanwhile,large-sized Al_3(Zr,Ti)phases formed and degraded the mechanical properties.Subsequent introduction of Ce resulted in the poisoning effect and reduced mechanical properties. 展开更多
关键词 aluminium alloy high-pressure die-casting externally solidified crystals non-heat treatment
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Effect of external and internal cues on core muscle activation during the Sahrmann five-level core stability test
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作者 Skyla Stifter Jessie McCaffrey +2 位作者 Tyler Nichols Ayse Ozcan Edeer Justine Ward 《World Journal of Methodology》 2025年第1期95-104,共10页
BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of cor... BACKGROUND Pain in the back or pelvis or fear of back pain may affect the timing or cocontraction of the core muscles.In both static and dynamic movements,the Sahrmann core stability test provides an assessment of core muscle activation and a person's ability to stabilize the lumbopelvic complex.Preparatory cues and images can be used to increase the activation of these muscles.To attain optimal movement patterns,it will be necessary to determine what cueing will give the most effective results for core stability.AIM To investigate the effects of external and internal cues on core muscle activation during the Sahrmann five-level core stability test.METHODS Total 68 participants(21.83±3.47 years)were randomly allocated to an external(n=35)or internal cue group(n=33).Participants performed the Sahrmann fivelevel core stability test without a cue as baseline and the five-level stability exercises with an internal or external cue.External cue group received a pressure biofeedback unit(PBU),and the internal cue group received an audio cue.A Delsys Trigno^(TM)surface electromyography unit was used for muscle activation from the rectus abdominis,external oblique,and transverse abdominis/internal oblique muscles.RESULTS Linear mixed effects model analysis showed that cueing had a significant effect on core muscle activation(P=0.001);however,there was no significant difference between cue types(internal or external)(P=0.130).CONCLUSION Both external and internal cueing have significant effects on core muscle activation during the Sahrmann five-level core stability test and the PBU does not create higher muscle activation than internal cueing. 展开更多
关键词 external cue Internal cue Muscle activation Core muscles Lumbopelvic stability Pressure biofeedback unit
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Innovation in Chinese Agribusinesses: Internal Resources and External Networks
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作者 Danhong Chen David Abler +1 位作者 Xia Gao Qijie Gao 《Journal of Agricultural Science and Technology(B)》 2013年第9期635-647,共13页
The existing literature on innovation concentrates mostly on large industrial firms and high-technology industries, whereas, little attention has been given to agribusiness. Empirical evidence regarding the driving fo... The existing literature on innovation concentrates mostly on large industrial firms and high-technology industries, whereas, little attention has been given to agribusiness. Empirical evidence regarding the driving forces behind innovation in agribusinesses in developing countries, China in particular is scarce. This paper helps fill that void. It develops a framework in which innovation results from synergies between internal resources and external networks. This paper applies and tests the framework using 2003-2005 data from a panel survey of 32 leading agribusiness firms in Shandong Province, China. The empirical results indicate the importance of internal resources, external networks and the synergies between them. We find that R&D expenditures and the number of technical employees are internal resources that are both important to product innovation. Surprisingly, management quality is negatively related to the possession of a unique technology and new products as a proportion of all products. It is possible that management quality is associated with more formalization and rigidity in decision-making, hindering creativity and lengthening the new product development cycle. In order to develop innovative products, our results suggest that investing in R&D and hiring more technical staff may be more effective approaches than spending on managerial talent. 展开更多
关键词 Chinese agribusiness external networks internal resources product innovation synergies.
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Mechanical Performance of Bio-inspired Bidirectional Corrugated Sandwich Pressure Shell Under External Hydrostatic Pressure 被引量:1
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作者 ZHANG Yi CHEN Yue +1 位作者 YUN Lai LIANG Xu 《China Ocean Engineering》 SCIE EI CSCD 2024年第2期297-312,共16页
This paper aims to enhance the compression capacity of underwater cylindrical shells by adopting the corrugated sandwich structure of cuttlebone.The cuttlebone suffers uniaxial external compression,while underwater cy... This paper aims to enhance the compression capacity of underwater cylindrical shells by adopting the corrugated sandwich structure of cuttlebone.The cuttlebone suffers uniaxial external compression,while underwater cylindrical shells are in a biaxial compressive stress state.To suit the biaxial compressive stress state,a novel bidirectional corrugated sandwich structure is proposed to improve the bearing capacity of cylindrical shells.The static and buckling analysis for the sandwich shell and the unstiffened cylindrical shell with the same volume-weight ratio are studied by numerical simulation.It is indicated that the proposed sandwich shell can effectively reduce the ratio between circumferential and axial stress from 2 to 1.25 and improve the critical buckling load by about 1.63 times.Numerical simulation shows that optimizing and adjusting the structural parameters could significantly improve the advantage of the sandwich shell.Then,the hydrostatic pressure tests for shell models fabricated by 3D printing are carried out.According to the experimental results,the overall failure position of the sandwich shell is at the center part of the sandwich shell.It has been found the average critical load of the proposed sandwich shell models exceeds two times that of the unstiffened shell models.Hence,the proposed bio-inspired bidirectional corrugated sandwich structure can significantly enhance the pressure resistance capability of cylindrical shells. 展开更多
关键词 bio-inspiration bidirectional corrugation sandwich shell external pressure BUCKLING
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Effects of vacancy and external electric field on the electronic properties of the MoSi_(2)N_(4)/graphene heterostructure 被引量:1
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作者 梁前 罗祥燕 +3 位作者 钱国林 王远帆 梁永超 谢泉 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第3期542-550,共9页
Recently,the newly synthesized septuple-atomic layer two-dimensional(2D)material MoSi_(2)N_(4)(MSN)has attracted attention worldwide.Our work delves into the effect of vacancies and external electric fields on the ele... Recently,the newly synthesized septuple-atomic layer two-dimensional(2D)material MoSi_(2)N_(4)(MSN)has attracted attention worldwide.Our work delves into the effect of vacancies and external electric fields on the electronic properties of the MSN/graphene(Gr)heterostructure using first-principles calculation.We find that four types of defective structures,N-in,N-out,Si and Mo vacancy defects of monolayer MSN and MSN/Gr heterostructure are stable in air.Moreover,vacancy defects can effectively modulate the charge transfer at the interface of the MSN/Gr heterostructure as well as the work function of the pristine monolayer MSN and MSN/Gr heterostructure.Finally,the application of an external electric field enables the dynamic switching between n-type and p-type Schottky contacts.Our work may offer the possibility of exceeding the capabilities of conventional Schottky diodes based on MSN/Gr heterostructures. 展开更多
关键词 MoSi_(2)N_(4) vacancy defects external electric field Schottky contacts
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Unraveling the efficacy network: A network meta-analysis of adjuvant external beam radiation therapy methods after hepatectomy 被引量:1
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作者 Gao-Yuan Yang Zhi-Wei He +7 位作者 Yong-Chang Tang Feng Yuan Ming-Bo Cao Yu-Peng Ren Yu-Xuan Li Xiao-Rui Su Zhi-Cheng Yao Mei-Hai Deng 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第1期205-214,共10页
BACKGROUND Primary liver cancer is a malignant tumor with a high recurrence rate that significantly affects patient prognosis.Postoperative adjuvant external radiation therapy(RT)has been shown to effectively prevent ... BACKGROUND Primary liver cancer is a malignant tumor with a high recurrence rate that significantly affects patient prognosis.Postoperative adjuvant external radiation therapy(RT)has been shown to effectively prevent recurrence after liver cancer resection.However,there are multiple RT techniques available,and the differ-ential effects of these techniques in preventing postoperative liver cancer re-currence require further investigation.AIM To assess the advantages and disadvantages of various adjuvant external RT methods after liver resection based on overall survival(OS)and disease-free survival(DFS)and to determine the optimal strategy.METHODS This study involved network meta-analyses and followed the PRISMA guidelines.The data of qualified studies published before July 10,2023,were collected from PubMed,Embase,the Web of Science,and the Cochrane Library.We included relevant studies on postoperative external beam RT after liver resection that had OS and DFS as the primary endpoints.The magnitudes of the effects were determined using risk ratios with 95%confidential intervals.The results were analyzed using R software and STATA software.RESULTS A total of 12 studies,including 1265 patients with hepatocellular carcinoma(HCC)after liver resection,were included in this study.There was no significant heterogeneity in the direct paired comparisons,and there were no significant differences in the inclusion or exclusion criteria,intervention measures,or outcome indicators,meeting the assumptions of heterogeneity and transitivity.OS analysis revealed that patients who underwent stereotactic body radiotherapy(SBRT)after resection had longer OS than those who underwent intensity modulated radiotherapy(IMRT)or 3-dimensional conformal RT(3D-CRT).DFS analysis revealed that patients who underwent 3D-CRT after resection had the longest DFS.Patients who underwent IMRT after resection had longer OS than those who underwent 3D-CRT and longer DFS than those who underwent SBRT.CONCLUSION HCC patients who undergo liver cancer resection must consider distinct advantages and disadvantages when choosing between SBRT and 3D-CRT.IMRT,a RT technique that is associated with longer OS than 3D-CRT and longer DFS than SBRT,may be a preferred option. 展开更多
关键词 Primary liver cancer Hepatocellular carcinoma Network meta-analysis external beam radiation therapy Stereotactic body radiotherapy Intensity modulated radiotherapy
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Mapping and resource evaluation of deep high-temperature geothermal resources in the Jiyang Depression,China
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作者 Shaozheng Wang Yaoqi Zhou +5 位作者 Xin Zhang Yangzhou Wang Yonghong Yang Yuehan Shang Yang Chen Xiaoxin Shi 《Energy Geoscience》 EI 2024年第4期142-155,共14页
In China,geothermal resource utilization has mainly focused on resources at shallow and medium depths.Yet,the exploration of deep,high-temperature geothermal resources holds significant importance for achieving the“d... In China,geothermal resource utilization has mainly focused on resources at shallow and medium depths.Yet,the exploration of deep,high-temperature geothermal resources holds significant importance for achieving the“dual carbon”goals and the transition of energy structure.The Jiyang Depression in the Bohai Bay Basin has vast potential for deep,high-temperature geothermal resources.By analyzing data from 2187 wells with temperature logs and 270 locations for temperature measurement in deep strata,we mapped the geothermal field of shallow to medium-deep layers in the Jiyang Depression using ArcGIS and predicted the temperatures of deep layers with a burial depth of 4000 m.Through stochastic modeling and numerical simulation,a reservoir attribute parameter database for favorable deep,high-temperature geothermal areas was developed,systematically characterizing the spatial distribution of geothermal resources within a play fairway of 139.5 km2 and estimating the exploitable deep geothermal resource potential by using the heat storage method and Monte Carlo data analysis.The study reveals that the Fan 54 well block in the Boxing-Jijia region is of prime significance to develop deep,high-temperature geothermal resources in the Jiyang Depression.Strata from the Cenozoic to the Upper Paleozoic are identified as effective cap layers for these deep geothermal resources.The Lower Paleozoic capable of effectively storing thermal energy and possessing an exploitable resource volume up to 127 million tons of standard coal,is identified as a target system for the development of deep high-temperature geothermal resources,providing significant insights for the efficient development of geothermal resources in the Jiyang Depression. 展开更多
关键词 Deep high-temperature geothermal resource Geological modeling Resource assessment Lower Paleozoic Jiyang Depression
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Effect of external magnetic field on the instability of THz plasma waves in nanoscale graphene field-effect transistors
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作者 张丽萍 孙宗耀 +1 位作者 李佳妮 苏俊燕 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期683-689,共7页
The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas w... The instability of plasma waves in the channel of field-effect transistors will cause the electromagnetic waves with THz frequency.Based on a self-consistent quantum hydrodynamic model,the instability of THz plasmas waves in the channel of graphene field-effect transistors has been investigated with external magnetic field and quantum effects.We analyzed the influence of weak magnetic fields,quantum effects,device size,and temperature on the instability of plasma waves under asymmetric boundary conditions numerically.The results show that the magnetic fields,quantum effects,and the thickness of the dielectric layer between the gate and the channel can increase the radiation frequency.Additionally,we observed that increase in temperature leads to a decrease in both oscillation frequency and instability increment.The numerical results and accompanying images obtained from our simulations provide support for the above conclusions. 展开更多
关键词 graphene field-effect transistors external magnetic field radiation frequency instability increment
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Adaptive Nonlinear PD Controller of Two-Wheeled Self-Balancing Robot with External Force
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作者 Van-Truong Nguyen Dai-Nhan Duong +3 位作者 Dinh-Hieu Phan Thanh-Lam Bui Xiem HoangVan Phan Xuan Tan 《Computers, Materials & Continua》 SCIE EI 2024年第11期2337-2356,共20页
This paper proposes an adaptive nonlinear proportional-derivative(ANPD)controller for a two-wheeled self-balancing robot(TWSB)modeled by the Lagrange equation with external forces.The proposed control scheme is design... This paper proposes an adaptive nonlinear proportional-derivative(ANPD)controller for a two-wheeled self-balancing robot(TWSB)modeled by the Lagrange equation with external forces.The proposed control scheme is designed based on the combination of a nonlinear proportional-derivative(NPD)controller and a genetic algorithm,in which the proportional-derivative(PD)parameters are updated online based on the tracking error and the preset error threshold.In addition,the genetic algorithm is employed to adaptively select initial controller parameters,contributing to system stability and improved control accuracy.The proposed controller is basic in design yet simple to implement.The ANPD controller has the advantage of being computationally lightweight and providing high robustness against external forces.The stability of the closed-loop system is rigorously analyzed and verified using Lyapunov theory,providing theoretical assurance of its robustness.Simulations and experimental results show that the TWSB robot with the proposed ANPD controller achieves quick balance and tracks target values with very small errors,demonstrating the effectiveness and performance of the proposed controller.The proposed ANPD controller demonstrates significant improvements in balancing and tracking performance for two-wheeled self-balancing robots,which has great applicability in the field of robot control systems.This represents a promising solution for applications requiring precise and stable motion control under varying external conditions. 展开更多
关键词 Two-wheeled self-balancing robot nonlinear PD control external force genetic algorithm
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An externally perceivable smart leaky-wave antenna based on spoof surface plasmon polaritons
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作者 Weihan Li Jia Chen +6 位作者 Shizhao Gao Lingyun Niu Jiaxuan Wei Ruosong Sun Yaqi Wei Wenxuan Tang Tie Jun Cui 《Opto-Electronic Advances》 SCIE EI CAS CSCD 2024年第9期5-20,共16页
Smart antennas have received great attention for their potentials to enable communication and perception functions at the same time.However,realizing the function synthesis remains an open challenge,and most existing ... Smart antennas have received great attention for their potentials to enable communication and perception functions at the same time.However,realizing the function synthesis remains an open challenge,and most existing system solutions are limited to narrow operating bands and high complexity and cost.Here,we propose an externally perceivable leakywave antenna(LWA)based on spoof surface plasmon polaritons(SSPPs),which can realize adaptive real-time switching between the“radiating”and“non-radiating”states and beam tracking at different frequencies.With the assistance of computer vision,the smart SSPP-LWA is able to detect the external target user or jammer,and intelligently track the target by self-adjusting the operating frequency.The proposed scheme helps to reduce the power consumption through dynamically controlling the radiating state of the antenna,and improve spectrum utilization and avoid spectrum conflicts through intelligently deciding the radiating frequency.On the other hand,it is also helpful for the physical layer communication security through switching the antenna working state according to the presence of the target and target beam tracking in real time.In addition,the proposed smart antenna can be generalized to other metamaterial systems and could be a candidate for synaesthesia integration in future smart antenna systems. 展开更多
关键词 smart antenna external perception spoof surface plasmon polaritons computer vision aids
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Practical Use of the Subjective Mathematical Model of Bayes and Its External Validation in Dental Medicine & Dentistry
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作者 Muyembi Muinaminayi Pierre Kayembe Mwimbi David +9 位作者 Nyimi Boshabu Fidèle Panoumvita Kapamona Junior Nsudila Mpoyi Monique Tubanza Mulongo Simplot Sekele Issouradi-Bourley Jean-Paul Mantshumba Milolo Augustin Kalala Kazadi Em Mabela Rosti Munyanga Mukongo Sylvain Dan Wang 《Open Journal of Statistics》 2024年第5期553-575,共23页
Objective: Our study aims to validate the subjective Bayes mathematical model using the mathematical model of logistic regression. Expert systems are being utilized increasingly in medical fields for the purposes of a... Objective: Our study aims to validate the subjective Bayes mathematical model using the mathematical model of logistic regression. Expert systems are being utilized increasingly in medical fields for the purposes of assisting diagnosis and treatment planning in Dentistry. Existing systems used few symptoms for dental diagnosis. In Dentistry, few symptoms are not enough for diagnosis. In this research, a conditional probability model (Bayes rule) was developed with increased number of symptoms associated with a disease for diagnosis. A test set of recurrent cases was then used to test the diagnostic capacity of the system. The generated diagnosis matched that of the human experts. The system was also tested for its capacity to handle uncommon dental diseases and the system portrayed useful potential. Method: The study used the Subjective Mathematical Bayes Model (SBM) approach and employed Logistic Regression Mathematical Model (LMR) techniques. The external validation of the subjective mathematical Bayes model (MSB) concerns the real cases of 625 patients who developed alveolar osteitis (OA). We propose strategies for reproducibility and reporting standards, outlining an updated WAMBS (when to Worry and how to Avoid the Misuse of Bayesian Statistics) checklist. Finally, we outline the impact of Bayesian analysis Logistic Regression Mathematical Model (LMR) techniques and on artificial intelligence, a major goal in the next decade. Results: The internal validation had identified seven (7) etiological factors of OA, which will be compared to the cases of MRL, for the external validation which retained six (6) etiological factors of OA. The experts in the internal validation of the MSB had generated 40 cases of OA and a COP of (0.5), which will be compared to the MRL that collected 625 real cases of OA to produce a Cop of (0.6) in the external validation, which discriminates between healthy patients (Se) and sick patients (Sp). Compared to real cases and the logistic regression model, the Bayesian model is efficient and its validity is established. 展开更多
关键词 external Validation-MSB-MRL Mathematical Model
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Effect of slow shot speed on externally solidified crystal,porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy
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作者 Wen-ning Liu Wei Zhang +6 位作者 Peng-yue Wang Yi-xian Liu Xiang-yi Jiao Ao-xiang Wan Cheng-gang Wang Guo-dong Tong Shou-mei Xiong 《China Foundry》 SCIE EI CAS CSCD 2024年第1期11-19,共9页
The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron mi... The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron microscopy(SEM)and laboratory computed tomography(CT).Results showed that the newly developed AlSi9MnMoV alloy exhibited improved mechanical properties when compared to the AlSi10MnMg alloy.The AlSi9MnMoV alloy,which was designed with trace multicomponent additions,displays a notable grain refining effect in comparison to the AlSi10MnMg alloy.Refining elements Ti,Zr,V,Nb,B promote heterogeneous nucleation and reduce the grain size of primaryα-Al.At a lower slow shot speed,the large ESCs are easier to form and gather,developing into the dendrite net and net-shrinkage.With an increase in slow shot speed,the size and number of ESCs and porosities significantly reduce.In addition,the distribution of ESCs is more dispersed and the net-shrinkage disappears.The tensile property is greatly improved by adopting a higher slow shot speed.The ultimate tensile strength is enhanced from 260.31 MPa to 290.31 MPa(increased by 11.52%),and the elongation is enhanced from 3.72%to 6.34%(increased by 70.52%). 展开更多
关键词 hypoeutectic Al-Si alloy high pressure die casting POROSITY externally solidified crystal tensile property
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Ethics of Human Resources Management in the Cameroonian Health System, Medical Nomadism and the Ineffectiveness of the Fight against High Blood Pressure
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作者 Jean Ndibi Abanda Anicet Onana Akoa +2 位作者 Désiré Tchoffo Ulrich Dama Pierre Yassa Yoniene 《Health》 2024年第1期9-21,共13页
Context/objectives: The fight against Chronic Non-Communicable Diseases (NCDs) is a long-term undertaking, which requires available, motivated and well-managed human resources (HR). The administrative management of sk... Context/objectives: The fight against Chronic Non-Communicable Diseases (NCDs) is a long-term undertaking, which requires available, motivated and well-managed human resources (HR). The administrative management of skills on both qualitative and quantitative levels is one of the essential functions of a health system. To better implement policies of fight against High Blood Pressure (HBP) and other chronic diseases, it is important to establish strategies to retain health personnel. This loyalty requires favorable working conditions and consideration of the contribution-reward couple. Good working conditions are likely to reduce the phenomenon of medical nomadism;conversely, poor HR management can contribute to their exodus towards exotic “green pastures”, thus leading to an additional crisis in the Cameroonian health system. The fight against HBP is a complex, multifaceted and multifactorial reality that requires appropriate management model for all types of resources mainly HR. The main objective of this research is to show the impact of poor management of human resources in Cameroon health system on medical nomadism and the ineffectiveness of the fight against High Blood Pressure. Method: A cross-sectional descriptive survey among five hundred (500) health facilities in the center region of Cameroon has been conducted. A stratified probabilistic technique has been used, and the number of health facilities to be surveyed has been determined using the “sample size estimation table” of Depelteau. The physical questionnaires have been printed and then distributed to data collectors. After data collection, the latter were grouped during processing in Excel sheets. The Chi-square test was used for data with a qualitative value and that of Kolmogorov-Sminorf for data with a quantitative value to assess the normality and reliability of data. The Crochach’s Alpha reliability test allowed us to have a summary of the means and variances and then to search for intragroup correlations between variables. Descriptive analysis was possible with the XLSTAT 2016 software. Results: 43.60% of Health Facilities (HF) managers were unqualified. 82.20% of HF managers have staff in a situation of professional insecurity. They are mainly contractual (49.00), decision-making agents (24.40%), casual agents (08.80). The proportion of unstable personnel is average of 22.00% and very unstable, 12.00%. 展开更多
关键词 ETHICS Human resources Management Cameroonian Health System Medical Nomadism Ineffectiveness High Blood Pressure
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Critical issues in the characteristics and assessment of China's water resources
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作者 Yu-hong Fei Su-hua Meng +2 位作者 Ya-song Li Peng-wei Zhang Xi-lin Bao 《Journal of Groundwater Science and Engineering》 2024年第4期463-474,共12页
This study provides a comprehensive analysis of the concepts and assessment processes of water resources in China,focusing on the characteristics of water resources and variations in water cycle fluxes.It reveals that... This study provides a comprehensive analysis of the concepts and assessment processes of water resources in China,focusing on the characteristics of water resources and variations in water cycle fluxes.It reveals that the distribution of water resources in China is uneven,with more south and less north,and human activities have led to a decline in water resources,particularly in northern arid and semi-arid regions.Further analysis shows that duplicated measurements of surface water and groundwater significantly affect water balance calculation and water resource assessments,serving as a crucial factor guiding water resource development and utilization.The study also finds that consistency correction of runoff series is insufficient to meet the requirements of accurate water resource assessment.It is urgent to strengthen fundamental research in hydrology and hydrogeology,and to establish a dynamic assessment system for the efficient management and rational use of surface water and groundwater in the current changing environment. 展开更多
关键词 Surface water resources Groundwater resources Assessment concepts Duplicated measurement Restoration measurement
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Comparison of the effect of different external electrodes on discharge plasma-assisted diffusion flame stabilization
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作者 Siyin ZHOU Xiang LIU +1 位作者 Wansheng NIE Shuhui YUAN 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第10期123-132,共10页
To optimize the design of plasma injectors,the influence of different external electrodes on plasma-assisted flame stabilization was assessed by using a nonequilibrium plasma injector flame control setup.The electrica... To optimize the design of plasma injectors,the influence of different external electrodes on plasma-assisted flame stabilization was assessed by using a nonequilibrium plasma injector flame control setup.The electrical characteristics of the injector,flame structure parameters,flame intensity,discharge power,and cost-to-effectiveness ratio under different external electrodes(four mesh electrodes and one copper foil electrode)were analyzed using electrical and optical methods.The results show that reducing the mesh size of the external electrode leads to a decrease in breakdown voltage.Compared with a ceramic dielectric barrier-based injector,an injector with a quartz dielectric barrier produces a higher breakdown voltage under the same conditions.For the same actuation voltage,the discharge current increases as the mesh size of the external electrode decreases,and combustion is enhanced by the discharge plasma;therefore,it is better to adopt a smaller mesh hole size to realize good flame stabilization under a lower actuation voltage.However,under the studied working conditions,reducing the mesh hole size of the external electrode increases the cost-to-effectiveness ratio of plasma injector-based flame stabilization.Thus,considering the cost-to-effectiveness ratio and the weight of the injector,an external electrode with a larger mesh hole size should be chosen,which contradicts the above rule. 展开更多
关键词 flame stabilization alternating current driven dielectric barrier discharge plasma injector plasma-assisted combustion external electrode
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Knowledge mapping of research on sustainable utilization of landscape resources:a case study of Guilin National Innovation Demonstration Zone for sustainable development in China
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作者 Xiuxiu Gao Yang Li +1 位作者 Yijue Li Zheng He 《Chinese Journal of Population,Resources and Environment》 2024年第3期326-333,共8页
Worldwide interest has increasingly focused on the sustainable utilization of landscape as a resource in urban areas,emphasizing its ecological,cultural and social significance.This study examines Guilin City,China,as... Worldwide interest has increasingly focused on the sustainable utilization of landscape as a resource in urban areas,emphasizing its ecological,cultural and social significance.This study examines Guilin City,China,as a representative case study due to its rich landscape resources and status as a national innovation demonstration zone for implementing the 2030 Agenda for Sustainable Development.This study uses bibliometric visualization tools like CiteSpace and VOSviewer to analyze research trends from 1980 to 2021 in the Chinese Academic Journal Network Publishing Database(CNKI).The results show increasing academic interest over three stages:initiation(1982-1997),exploration(1998-2004),and diversified development(2005-2021).Contributions are predominantly from local academic and tourism sectors,indicating a strong regional influence;however,relatively weak interinstitutional collaboration occurs,suggesting potential for more integrated research efforts.Primary research is also concentrated within economic disciplines,particularly tourism-related ones.The evolution of research frontiers reveals three main paths:urban development strategies,industrial economic theories and empirical validation,and ecosystem analysis and evaluation.A multidisciplinary approach and stronger collaborative efforts are crucial to enhance research on ecological values and empirical models while supporting evidence-based urban development strategies in Guilin City and comparable cities globally. 展开更多
关键词 Sustainable development Landscape resources Bibliometric analysis Knowledge mapping
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Joint Allocation of Computing and Connectivity Resources in Survivable Inter-Datacenter Elastic Optical Networks
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作者 Yang Tao Li Yang Chen Xue 《China Communications》 SCIE CSCD 2024年第8期172-181,共10页
Inter-datacenter elastic optical networks(EON)need to provide the service for the requests of cloud computing that require not only connectivity and computing resources but also network survivability.In this paper,to ... Inter-datacenter elastic optical networks(EON)need to provide the service for the requests of cloud computing that require not only connectivity and computing resources but also network survivability.In this paper,to realize joint allocation of computing and connectivity resources in survivable inter-datacenter EONs,a survivable routing,modulation level,spectrum,and computing resource allocation algorithm(SRMLSCRA)algorithm and three datacenter selection strategies,i.e.Computing Resource First(CRF),Shortest Path First(SPF)and Random Destination(RD),are proposed for different scenarios.Unicast and manycast are applied to the communication of computing requests,and the routing strategies are calculated respectively.Simulation results show that SRMLCRA-CRF can serve the largest amount of protected computing tasks,and the requested calculation blocking probability is reduced by 29.2%,28.3%and 30.5%compared with SRMLSCRA-SPF,SRMLSCRA-RD and the benchmark EPS-RMSA algorithms respectively.Therefore,it is more applicable to the networks with huge calculations.Besides,SRMLSCRA-SPF consumes the least spectrum,thereby exhibiting its suitability for scenarios where the amount of calculation is small and communication resources are scarce.The results demonstrate that the proposed methods realize the joint allocation of computing and connectivity resources,and could provide efficient protection for services under single-link failure and occupy less spectrum. 展开更多
关键词 computing and connectivity interdatacenter networks joint resource allocation service protection
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Analysis of the Variability of the Characteristics of Water Resources in the Diani Watershed: Case of the Silissou District
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作者 Mohamed Pivi Traore Amadou Lamarana Bah +1 位作者 Mohamed Ansoumane Camara Mamby Keita 《Journal of Energy and Power Engineering》 CAS 2024年第3期119-126,共8页
This study aims to analyze the spatio-temporal variability of the characteristics of water resources in the Diani watershed,located in the southeast of the Republic of Guinea.The objective is to assess the availabilit... This study aims to analyze the spatio-temporal variability of the characteristics of water resources in the Diani watershed,located in the southeast of the Republic of Guinea.The objective is to assess the availability and quantity of water for sustainable management of this essential resource.The results obtained show a slight variability of hydro-climatic parameters.The most remarkable wet periods by their intensity of(1982-1998)and(2005-2012)are moderate and that of 1986-1990 is extremely severe during which they are felt on all the stations of the South of Guinea.In addition,the dry years,the end of 1970 and 1980 to 1987 recognized by the WMO(World Meteorological Organization)as drought years were highlighted in the Diani watershed in the South of the Republic of Guinea. 展开更多
关键词 VARIABILITY CHARACTERISTICS resources water
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Linking 24-h Movement Behavior Guidelines to Cognitive Difficulties,Internalizing and Externalizing Problems in Preterm Youth
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作者 Zhihui Cheng Ailikute Aikeremu +6 位作者 Yanping Gao Zhihao Zhang Anthony G.Delli Paoli Paolo Marcello Cunha Alyx Taylor Fabian Herold Liye Zou 《International Journal of Mental Health Promotion》 2024年第8期651-662,共12页
Background:Given the heightened risk of developmental challenges associated with preterm birth,it is crucial to explore interventions that may ameliorate potential adverse outcomes.This study aimed to examine whether ... Background:Given the heightened risk of developmental challenges associated with preterm birth,it is crucial to explore interventions that may ameliorate potential adverse outcomes.This study aimed to examine whether meeting the 24-h movement behavior(24-HMB)guidelines,which include recommendations on physical activity(PA),screen time(ST),and sleep(SL),is related to indicators of cognitive difficulties,internalizing problems(e.g.,depression and anxiety),and externalizing problems(e.g.,difficulties in making friends and arguing)in a sample of preterm youth(children and adolescents born preterm).Methods:In this cross-sectional study,data from 3410 preterm youth(aged 6 to 17 years)were included for data analyses.Multivariable logistic regression was used to investigate associations between meeting the 24-HMB guidelines and the above-mentioned health outcomes,while controlling for sociodemographic and health-related factors.Results:The prevalence of meeting 24-HMB guidelines varied across independent and integrated components of the 24-HMB guidelines.Meeting the ST guideline alone(p<0.05)and integrated guidelines(i.e.,ST+SL and ST+SL+PA)were associated with fewer cognitive difficulties and reduced internalizing and externalizing problems(p<0.05).Specifically,meeting the SL guideline alone and integrated guidelines(i.e.,SL+ST)were associated with lower odds of depression and anxiety(p<0.01).Additionally,meeting independent,and integrated(PA and/or ST)guidelines were associated with less pronounced difficulties in making friends and arguing(p<0.05).Meeting 24-HMB guidelines in an isolated and integrated manner are linked to better cognitive performance and fewer internalizing and externalizing problems in preterm youth.Conclusion:Results suggest that advocating for the implementation of the 24-HMB guidelines may reduce cognitive challenges and behavioral issues,which is of high relevance for improving public health.Future longitudinal studies in preterm youth should investigate how modifying specific 24-HMB behaviors,especially ST,influence cognitive difficulties,internalizing and externalizing problems in this vulnerable population. 展开更多
关键词 Cognitive difficulties externalizing problems internalizing problems physical activity preterm youth
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Spatial and Temporal Distribution Characteristics of Solar Energy Resources in Tibet
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作者 Yanbo Shen Yang Gao +3 位作者 Yueming Hu Xin Yao Wenzheng Yu Yubing Zhang 《Energy Engineering》 EI 2024年第1期43-57,共15页
The Tibet Plateau is one of the regions with the richest solar energy resources in the world.In the process of achieving carbon neutrality in China,the development and utilization of solar energy resources in the regi... The Tibet Plateau is one of the regions with the richest solar energy resources in the world.In the process of achieving carbon neutrality in China,the development and utilization of solar energy resources in the region will play an important role.In this study,the gridded solar resource data with 1km resolution in Tibet were obtained by spatial correction and downscaling of SMARTS model.On this basis,the spatial and temporal distribution characteristics of solar energy resources in the region in the past 30 years(1991–2020)are finely evaluated,and the annual global horizontal radiation resource is calculated.The results show that:1)The average annual global horizontal radiation amount in Tibet is 1816 kWh/m^(2).More than 60%of the area belongs to the“Most abundant”(GHI≥1750 kWh/m^(2))area of China’s solar energy resources category A,and nearly 40%belongs to the“Quite abundant”(1400≤GHI<1750)area of China’s solar energy resource category B.2)In space,the solar energy resources in Tibet increased gradually from north to south and from east to west.Lhasa,Central and Eastern Shigatse,Shannan,and Southwestern Ali are the most abundant cities,with a maximum annual radiation level of 2189 kWh/m2.3)In terms of time,the total horizontal radiation in Tibet was the highest in May and the lowest in December.74%of the total area belongs to the“Very stable”(R_(w)≥0.47)area of solar resource stability category A,and 26%belongs to the“stable”(0.36≤R_(w)<0.47)area of solar resource stability category B.Solar energy resources in the region show the characteristics of both strong and stable.Average solar energy resources in the region have shown a fluctuating downward trend over the past 30 years,with an average decline of about 12.86(kWh/m2)per decade.4)In terms of solar radiation resources reaching the earth’s surface,the theoretical total amount of annual horizontal radiation in Tibet is about 240.07 billion tons of standard coal or 222.91 billion kilowatts on average. 展开更多
关键词 TIBET solar resource spatiotemporal distribution
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