At the township level,combining Voronoi diagram and breaking point theory,this paper divides township grade system and its scope of influence in Dafang County of Guizhou Province,and discusses the grade system from sm...At the township level,combining Voronoi diagram and breaking point theory,this paper divides township grade system and its scope of influence in Dafang County of Guizhou Province,and discusses the grade system from small scale perspective.Results show that Dafang County takes Dafang Town as the center,Dashi Town in the north and Shachang Township in the east as auxiliary part,Sanyuan Township,Zhuyuan Township,Babao Township,Pudi Township,Lihua Township,and Dingxin Township as cooperative part,to drive development of 36 townships in Dafang County.Thus,it basically reflects township grade of Dafang County,accords with current development situation,provides certain reference value for system planning and economic zoning of small scale regions,and it is able to improve the accuracy of scope division by completing attribute data and revision of many methods.展开更多
Objective:To evaluate the methodological quality of the systematic reviews(SRs)of acupuncture and moxibustion for chronic constipation and rate the evidence bodies of their Meta-analysis.Methods:We searched MEDLINE,EM...Objective:To evaluate the methodological quality of the systematic reviews(SRs)of acupuncture and moxibustion for chronic constipation and rate the evidence bodies of their Meta-analysis.Methods:We searched MEDLINE,EMBASE,Chinese Biomedical Literature Database(CBM),the China National Knowledge Infrastructure(CNKI),the VIP Database and the WanFang Database.Systematic Aseviews and Meta-analysis of all Randomized Controlled Trials(RCTs)of acupuncture and moxibustion for chronic constipation were included.Data from the included studies were extracted by two independent reviewers and were re-evaluated with AMSTAR 2 and Grades of Recommendation,Assessment,Development,and Evaluation(GRADE).Results:We included 12 SRs/Meta-analysis with only one conducted outside China.Evaluated with AMSTAR 2,methodology of one SR was of medium quality,methodologies of 7 SRs were of low quality,and methodologies of 4 SRs were of critical low quality.Among 54 outcome measures screened from included SRs,7 outcome measures introduced evidence bodies of moderate quality,22 outcome measures were of low quality and 25 outcome measures were of very low quality.No high level of quality was awarded to any evidence body.Conclusion:Overall,the quality level of SR/Meta-analysis of acupuncture/moxibustion for chronic constipation is low.The SRs/Meta-analysis of acupuncture/moxibustion for chronic constipation can be used for guideline formulation and clinical decision making by taking into account the experience of clinical experts,patients'preference,medical policies and other factors.展开更多
目的:系统评价培土生金中药联合西医常规疗法治疗支气管哮喘缓解期肺脾两虚证的疗效以及证据质量,为临床决策及疾病指南制订提供循证依据。方法:检索中国知网(CNKI)、万方数据库(Wangfang)、Pubmed、Web of Science等8大中英文数据库,由...目的:系统评价培土生金中药联合西医常规疗法治疗支气管哮喘缓解期肺脾两虚证的疗效以及证据质量,为临床决策及疾病指南制订提供循证依据。方法:检索中国知网(CNKI)、万方数据库(Wangfang)、Pubmed、Web of Science等8大中英文数据库,由2名研究者独立进行文献筛选、信息提取、偏倚风险评估及方法学质量评价,并对纳入研究的总有效率、中医证候积分、第一秒用力呼气容积(FEV1)、第一秒用力呼气容积/用力肺活量(FEV1/FVC)、哮喘控制测试(ACT)评分等结局指标进行Meta分析,最终依照GRADE评估证据质量。结果:共纳入14项研究,合计1263例患者。结果显示:(1)培土生金中药联合常规西医疗法可有效改善患者总有效率,降低患者中医证候积分,改善患者FEV1水平、FEV1/FVC及ACT评分。(2)总有效率证据质量较优,可信度高,其余指标证据质量较低,尚待更多高质量的研究支持以提升证据级别。结论:培土生金中药联合西医常规疗法治疗支气管哮喘缓解期肺脾两虚证优于单用西医常规治疗,且在总有效率上证据质量较高,具有一定的循证学意义。展开更多
With the continuous advancement of the internationalization of higher education in China,the Grade Point Average(GPA)has become a primary indicator for evaluating academic performance in universities,playing a positiv...With the continuous advancement of the internationalization of higher education in China,the Grade Point Average(GPA)has become a primary indicator for evaluating academic performance in universities,playing a positive role in educational management.However,as it is closely tied to students’immediate interests,such as awards,exemptions from entrance exams for postgraduate recommendations,and domestic or international further education,certain new issues have emerged in its practical application.These problems have hindered the effective functioning of the GPA system,attracting widespread attention.This paper examines the origin,connotation,and theoretical assumptions of the GPA system,discusses its positive functions and existing challenges,and proposes recommendations for further improving academic evaluation.展开更多
Purpose:This study aims to address the lack of a unified grading framework in Chinese reading by proposing a comprehensive model integrating linguistic complexity and reading experience,to evaluate the difficulty leve...Purpose:This study aims to address the lack of a unified grading framework in Chinese reading by proposing a comprehensive model integrating linguistic complexity and reading experience,to evaluate the difficulty level of Chinese books.Design/methodology/approach:We utilized the Probabilistic Fuzzy Linguistic Technique(PFLT)for subjective indicators related to reading experience.Combined with collected objective indicators data,the Entropy Weight Method(EWM)is used for objective weight allocation,and Tomada De Decisão Interativa Multicritério(TODIM)is applied for multi-criteria decision-making.Findings:The results demonstrate that the proposed framework significantly enhances the alignment between text complexity and reader engagement,achieving a high consistency with authoritative benchmarks.Research limitations:The study may be limited by the scope of subjective and objective indicators used;further validation with more diverse data sources could strengthen generalizability.Practical implications:This approach shows promise in advancing the standardization and objectivity of Chinese reading grading systems,with potential applications in educational and publishing contexts.Originality/value:This study offers a structured evaluation model that incorporates both linguistic complexity and experiential factors,providing a novel and comprehensive method for assessing Chinese text difficulty.展开更多
A multi-effect distillation technology for seawater desalination driven by tidal energy and low grade energy is presented.In the system,tidal energy is utilized to supply power instead of coventional electric pumps du...A multi-effect distillation technology for seawater desalination driven by tidal energy and low grade energy is presented.In the system,tidal energy is utilized to supply power instead of coventional electric pumps during the operation,resulting in the decrease of dependence on steady electric power supply and a reduction in the running costs.According to the technological principle,a testing unit is designed and built.The effects of the feed seawater temperature and the heat source temperature on the unit performance are tested and analyzed.The experimental results show that the fresh water output is 27 kg/h when the heating water temperature is 65 ℃ and the absolute pressure is 25 kPa.The experimental and theoretical analysis results indicate that the appropriate heating water temperature is a key factor in ensuring the steady operation of the system.展开更多
The 3-dimensional couple equations of magneto-electro-elastic structures are derived under Hamiltonian system based on the Hamilton principle. The problem of single sort of variables is converted into the problem of d...The 3-dimensional couple equations of magneto-electro-elastic structures are derived under Hamiltonian system based on the Hamilton principle. The problem of single sort of variables is converted into the problem of double sorts of variables, and the Hamilton canonical equations are established. The 3-dimensional problem of magneto-electro-elastic structure which is investigated in Euclidean space commonly is converted into symplectic system. At the same time the Lagrange system is converted into Hamiltonian system. As an example, the dynamic characteristics of the simply supported functionally graded magneto-electro-elastic material （FGMM） plate and pipe are investigated. Finally, the problem is solved by symplectic algorithm. The results show that the physical quantities of displacement, electric potential and magnetic potential etc. change continuously at the interfaces between layers under the transverse pressure while some other physical quantities such as the stress, electric and magnetic displacement are not continuous. The dynamic stiffness is increased by the piezoelectric effect while decreased by the piezomagnetic effect.展开更多
The thermal stresses relaxation of Ni/NiFe2O4 system functionally graded cermet inert anode for aluminum electrolysis was optimally designed. The transient thermal stresses of the inert anode under complex boundary co...The thermal stresses relaxation of Ni/NiFe2O4 system functionally graded cermet inert anode for aluminum electrolysis was optimally designed. The transient thermal stresses of the inert anode under complex boundary condition during high-temp （955℃） electrolysis were calculated using the finite-element software ANSYS, the influence of different parameters on the distribution of the thermal stresses were analyzed. The results showed that, during the process of thermal shock, the thermal hoop tensile stress on the surface of the anode is very large, which is possibly the major cause of anode crack; when the radius of the anode is between 0.05-0.15m, a range that can be realized by recent manufacturing technology, the optimum composition distribution exponent p is 0.25; The hoop tensile stresses reduce with the decrease of anode scale and also decrease with the decrease of the convection coefficient between the electrolyte and the anode.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)is a frequent cause of cancer related death globally.Neutrophil to lymphocyte ratio(NLR)and albumin bilirubin(ALBI)grade are emerging prognostic indicators in HCC.AIM To study p...BACKGROUND Hepatocellular carcinoma(HCC)is a frequent cause of cancer related death globally.Neutrophil to lymphocyte ratio(NLR)and albumin bilirubin(ALBI)grade are emerging prognostic indicators in HCC.AIM To study published literature of NLR and ALBI over the last five years,and to validate NLR and ALBI locally in our centre as indicators of HCC survival.METHODS A systematic review of the published literature on PubMed of NLR and ALBI in HCC over the last five years.The search followed the guidelines of the preferred reporting items for systematic reviews and meta-analyses.Additionally,we also investigated HCC cases between December 2013 and December 2018 in our centre.RESULTS There were 54 studies describing the relation between HCC and NLR and 95 studies describing the relation between HCC and ALBI grade over the last five years.Our local cohort of patients showed NLR to have a significant negative relationship to survival(P=0.011).There was also significant inverse relationship between the size of the largest HCC nodule and survival(P=0.009).Median survival with alpha fetoprotein(AFP)<10 KU/L was 20 mo and with AFP>10 KU/L was 5 mo.We found that AFP was inversely related to survival,this relationship was not statically significant(P=0.132).Mean survival for ALBI grade 1 was 37.7 mo,ALBI grade 2 was 13.4 months and ALBI grade 3 was 4.5mo.ALBI grades performed better than Child Turcotte Pugh score in detecting death from HCC.CONCLUSION NLR and ALBI grade in HCC predict survival better than the conventional alpha fetoprotein.ALBI grade performs better than Child Turcotte Pugh score.These markers are done as part of routine clinical care and in cases of normal alpha fetoprotein,these markers could give a better understanding of the patient disease progression.NLR and ALBI grade could have a role in modified easier to learn staging and prognostic systems for HCC.展开更多
Stream sediment geochemistry remains a versatile tool in exploration especially in regions where knowledge of the primary mineralization is lacking and the exploration activities are still at reconnaissance stage. In ...Stream sediment geochemistry remains a versatile tool in exploration especially in regions where knowledge of the primary mineralization is lacking and the exploration activities are still at reconnaissance stage. In this study, we investigate the concentrations of gold and associated elements in stream sediment samples from the Vaimba-Lidi drainage system in northern Cameroon;a relatively remote area where alluvial gold is worked locally, and exploration activities are at early stage. The main river and its principal first and second order tributaries were sampled, panned for gold grain recovery and the 100 μm size fraction analyzed for Au by fire assay with Ni finish. A suite of other elements were analyzed for by inductively coupled plasma mass spectrometry (ICP-MS). Gold grades estimated by the panning and weighing technique rarely exceed1 g/t while the Au concentrations from chemical analysis range from 3.0 to 354.0 ppm. The spatial distribution of gold and all the other elements are presented as point symbol maps and the data analyzed using multivariate statistics. From the principal component analysis (PCA), the As-Mo-W-Ag as well as the Au-Zn factors point to the presence of primary hydrothermal gold-sulphide mineralization in the area and this can be further investigated. These results highlight the importance of multielement analysis and multivariate statistical interpretation of sediment geochemical data in inferring the nature of the underlying primary mineralization in any region.展开更多
Coal has often been regarded as a problem additive to solve and improve the surface finish of iron castings,but at the same time causes other issues such as increased loss on ignition,total fines and moisture in syste...Coal has often been regarded as a problem additive to solve and improve the surface finish of iron castings,but at the same time causes other issues such as increased loss on ignition,total fines and moisture in system sands.Although many altermatives have been tried,there is no real substitute for thw all round properties of this wonderful natural resource.With the correct choice of coal,the combination of low ash,high volatile and swell index properties coupled with the key element of grading size,ensures castings are produced free from metal penetration and surface related problems.By careful selection,safe handling and processing coal continues to offer a good simple cost effective solution.Coal is subject to regulations in storage,processing and transportation and then further subjected to safe handling and use by the foundry.Despite these handicaps,it is still economical to the end user and modern processing and grading methods ensure it is used in the optimum condition to help produce quality castings.展开更多
In this work,a novel approach of leaching valuable metals,such as niobium,yttrium and cerium,from a niobium-bearing ore of low grade by roasting KHSO_(4)-H_(2)SO_(4)system was experimentally studied.Through the work,t...In this work,a novel approach of leaching valuable metals,such as niobium,yttrium and cerium,from a niobium-bearing ore of low grade by roasting KHSO_(4)-H_(2)SO_(4)system was experimentally studied.Through the work,the effects of roasting temperature,roasting time,mass ratio of agents to ore and the types of leaching agents on the extraction of Nb,Y and Ce were investigated,and the roasting KHSO_(4)-H_(2)SO_(4)-ore system was thought as an effective method to extract these valuable metals.It was found that the recovery of Nb,Y and Ce can,respectively,reach 90.20%,97.22%and 98.41%in condition of roasting temperature of 300℃,roasting time of 2 h,mass ratio of KHSO_(4)-to-H_(2)SO_(4)to ore of 0.5:1:1,particle size of-74 lm(~95%),leaching solution of oxalic acid(30 g·L^(-1)),leaching temperature of 90℃and leaching liquid-to-solid ratio of 5:1.The leaching kinetics of the calcined Nb-bearing ore in oxalic acid solution was successfully modeled by chemical reaction model,and the apparent activity energy was obtained to be14.16 kJ·mol^(-1).The results generated from this work will provide the fundamentals for extracting Nb,Y and Ce from a niobium-bearing ore of low grade and have potential applications value in future.展开更多
In patients with high grade gliomas (HGGs), progression after treatment can be difficult to diagnose due to treatment-related effects, which overlap in appearance with tumour progression on conventional magnetic reson...In patients with high grade gliomas (HGGs), progression after treatment can be difficult to diagnose due to treatment-related effects, which overlap in appearance with tumour progression on conventional magnetic resonance imaging (MRI) sequences. Specialised imaging methods have been studied for this purpose, though most institutions currently use histopathology or clinicoradiological follow-up for diagnosis. This publication aims to review the evidence for perfusion MRI techniques. The databases of Pubmed, MEDLINE, EMBASE and Scopus were searched using combinations of the subject headings high grade glioma and MRI perfusion. 41 articles fulfilled the inclusion criteria. Dynamic Susceptibility Contrast (DSC) MRI was the most extensively studied, with several studies achieving high sensitivities and specificities. Other techniques exhibiting potential include Dynamic Contrast Enhanced (DCE) MRI, Arterial Spin Labelling (ASL). However, these techniques are not widely used or available for clinical practice. Composite measures combining results from multiple techniques tended to achieve higher accuracies. Some publications compared processing software used or looked at machine learning with relative success. An issue common to the literature is the lack of standardisation in the reference standard and acquisition/processing methods. Furthermore, many had small sample sizes, and further consideration needs to be given with regards to timing of imaging, and treatment regimens received in such studies.展开更多
Wrinkles in flat graded elastic layers have been recently described as a timevarying Hamiltonian system by the energy method.Cylindrical core/shell structures can also undergo surface instabilities under the external ...Wrinkles in flat graded elastic layers have been recently described as a timevarying Hamiltonian system by the energy method.Cylindrical core/shell structures can also undergo surface instabilities under the external pressure.In this study,we show that by treating the radial direction as a pseudo-time variable,the graded core/shell system with radially decaying elastic properties can also be described within the symplectic framework.In combination with the shell buckling equation,the present paper addresses the surface wrinkling of graded core/shell structures subjected to the uniform external pressure by solving a series of ordinary differential equations with varying coefficients.Three representative gradient distributions are showcased,and the predicted critical pressure and critical wave number are verified by finite element simulations.The symplectic framework provides an efficient and accurate approach to understand the surface instability and morphological evolution in curved biological tissues and engineered structures.展开更多
By virtue of a complete set of two displacement potentials,an analytical derivation of the elastostatic Green’s functions of an exponentially graded transversely isotropic substrate–coating system is presented.Three...By virtue of a complete set of two displacement potentials,an analytical derivation of the elastostatic Green’s functions of an exponentially graded transversely isotropic substrate–coating system is presented.Three-dimensional point–load and patch–load Green’s functions for stresses and displacements are given in line-integral representations.The formulation includes a complete set of transformed stress–potential and displacement–potential relations,with utilizing Fourier series and Hankel transforms.As illustrations,the present Green’s functions are degenerated to the special cases such as an exponentially graded half-space and a homogeneous two-layered half-space Green’s functions.Because of complicated integrand functions,the integrals are evaluated numerically and for numerical computation of the integrals,a robust and effective methodology is laid out which gives the necessary account of the presence of singularities of integration.Comparisons of the existing numerical solutions for homogeneous two-layered isotropic and transversely isotropic half-spaces are made to confirm the accuracy of the present solutions.Some typical numerical examples are also given to show the general features of the exponentially graded two-layered half-space Green’s functions that the effect of degree of variation of material properties will be recognized.展开更多
We consider the large time behavior of a non-autonomous third grade fluid sys- tem, which could be viewed as a perturbation of the classical Navier-Stokes system. Under proper assumptions, we firstly prove that the fa...We consider the large time behavior of a non-autonomous third grade fluid sys- tem, which could be viewed as a perturbation of the classical Navier-Stokes system. Under proper assumptions, we firstly prove that the family of processes generated by the problem ad- mits a uniform attractor in the natural phase space. Then we prove the upper-semicontinuity of the uniform attractor when the perturbation tends to zero.展开更多
This paper reports that SiO2 is selected to fabricate broadband antireflection （AR） coatings on fused silica substrate by using glancing angle deposition and physical vapour deposition. Through accurate control of t...This paper reports that SiO2 is selected to fabricate broadband antireflection （AR） coatings on fused silica substrate by using glancing angle deposition and physical vapour deposition. Through accurate control of the graded index of the SiO2 layer, transmittance of thc graded broadband AR coating can achieve an average value of 98% across a spectral range of 300-1850 nm. Moreover, a laser-induced damage threshold measurement of the fabricated AR coating is performed by using a one-on-one protocol according to ISOl1254-1, resulting in an average damage threshold of 17.2 J/cm2.展开更多
In this paper,a multiscale model is developed for the mass functionally graded(FG)beam-fluid system to investigate its static and dynamic responses based on 3D printed porous beam free vibration tests,which are determ...In this paper,a multiscale model is developed for the mass functionally graded(FG)beam-fluid system to investigate its static and dynamic responses based on 3D printed porous beam free vibration tests,which are determined by two aspects.At the microstructural level,the gradient variation is realized by arbitrary distribution of matrix pores,and the effective moduli under specific distribution are obtained using the micromechanics homogenization theory.In the meantime,at the structural level,the mechanical responses of FG porous beams subjected to mass loading are considered in a static fluid environment.Then,the explicit expressions of local finite-element(FE)expressions corresponding to the static and dynamic responses are given in the appendices.The present results are validated against numerical and experimental results from the literature and mechanical tests of 3D printed structures,with good agreement generally obtained,giving credence to the present model.On this basis,a comprehensive parametric study is carried out,with a particular focus on the effects of boundary conditions,fluid density,and slenderness ratio on the bending and vibration of FG beams with several different gradations.展开更多
The availability of automated evaluation methodologies that may reliably be used for determining students’ scholastic performance through assigning letter grades are of utmost practical importance to educators, stude...The availability of automated evaluation methodologies that may reliably be used for determining students’ scholastic performance through assigning letter grades are of utmost practical importance to educators, students, and do invariably have pivotal values to all stakeholders of the academic process. In particular, educators use letter grades as quantification metrics to monitor students’ intellectual progress within a framework of clearly specified learning objectives of a course. To students grades may be used as predictive measures and motivating drives for success in a study field. However due to numerous objective and subjective variables that may by be accounted for in a methodological process of assigning students’ grades, and since such a process is often tainted with personal philosophy and human psychology factors, it is essential that educators exercise extra care in maximizing positive account of all objective factors and minimizing negative ramifications of subjectively fuzzy factors. To this end, and in an attempt to make assigning students’ grades more reliable for assessing true-level of mastering specified learning outcomes, this paper will: i) provide a literature review on previous works on the most common methods that have traditionally been in use for assigning students’ grades, and a short account of the virtues and/or vices of such methods, and ii) present a user-friendly computer code that may be easily adapted for the purpose of assigning students’ grades. This would relieve educators from the overwhelming concerns associated with mechanistic aspects of determining educational metrics, and it would allow them to have more time and focus to obtain reliable assessments of true-level of students’ mastery of learning outcomes by accounting for all possible evaluation components.展开更多
基金Supported the Project for Revision of Overall Land Use Plan for Dafang County(Guizhou University[2009]HT1226)Construction of Graphics Library for Dafang County([2011]1201)
文摘At the township level,combining Voronoi diagram and breaking point theory,this paper divides township grade system and its scope of influence in Dafang County of Guizhou Province,and discusses the grade system from small scale perspective.Results show that Dafang County takes Dafang Town as the center,Dashi Town in the north and Shachang Township in the east as auxiliary part,Sanyuan Township,Zhuyuan Township,Babao Township,Pudi Township,Lihua Township,and Dingxin Township as cooperative part,to drive development of 36 townships in Dafang County.Thus,it basically reflects township grade of Dafang County,accords with current development situation,provides certain reference value for system planning and economic zoning of small scale regions,and it is able to improve the accuracy of scope division by completing attribute data and revision of many methods.
基金Ministry of Science and Technology of the People's Republic of China,"Development of International Clinical Practice Guideline,Technical Operation Standard and Service Standard of Acupuncture and Moxibustion".Granting number:2019YFC1712200。
文摘Objective:To evaluate the methodological quality of the systematic reviews(SRs)of acupuncture and moxibustion for chronic constipation and rate the evidence bodies of their Meta-analysis.Methods:We searched MEDLINE,EMBASE,Chinese Biomedical Literature Database(CBM),the China National Knowledge Infrastructure(CNKI),the VIP Database and the WanFang Database.Systematic Aseviews and Meta-analysis of all Randomized Controlled Trials(RCTs)of acupuncture and moxibustion for chronic constipation were included.Data from the included studies were extracted by two independent reviewers and were re-evaluated with AMSTAR 2 and Grades of Recommendation,Assessment,Development,and Evaluation(GRADE).Results:We included 12 SRs/Meta-analysis with only one conducted outside China.Evaluated with AMSTAR 2,methodology of one SR was of medium quality,methodologies of 7 SRs were of low quality,and methodologies of 4 SRs were of critical low quality.Among 54 outcome measures screened from included SRs,7 outcome measures introduced evidence bodies of moderate quality,22 outcome measures were of low quality and 25 outcome measures were of very low quality.No high level of quality was awarded to any evidence body.Conclusion:Overall,the quality level of SR/Meta-analysis of acupuncture/moxibustion for chronic constipation is low.The SRs/Meta-analysis of acupuncture/moxibustion for chronic constipation can be used for guideline formulation and clinical decision making by taking into account the experience of clinical experts,patients'preference,medical policies and other factors.
文摘目的:系统评价培土生金中药联合西医常规疗法治疗支气管哮喘缓解期肺脾两虚证的疗效以及证据质量,为临床决策及疾病指南制订提供循证依据。方法:检索中国知网(CNKI)、万方数据库(Wangfang)、Pubmed、Web of Science等8大中英文数据库,由2名研究者独立进行文献筛选、信息提取、偏倚风险评估及方法学质量评价,并对纳入研究的总有效率、中医证候积分、第一秒用力呼气容积(FEV1)、第一秒用力呼气容积/用力肺活量(FEV1/FVC)、哮喘控制测试(ACT)评分等结局指标进行Meta分析,最终依照GRADE评估证据质量。结果:共纳入14项研究,合计1263例患者。结果显示:(1)培土生金中药联合常规西医疗法可有效改善患者总有效率,降低患者中医证候积分,改善患者FEV1水平、FEV1/FVC及ACT评分。(2)总有效率证据质量较优,可信度高,其余指标证据质量较低,尚待更多高质量的研究支持以提升证据级别。结论:培土生金中药联合西医常规疗法治疗支气管哮喘缓解期肺脾两虚证优于单用西医常规治疗,且在总有效率上证据质量较高,具有一定的循证学意义。
文摘With the continuous advancement of the internationalization of higher education in China,the Grade Point Average(GPA)has become a primary indicator for evaluating academic performance in universities,playing a positive role in educational management.However,as it is closely tied to students’immediate interests,such as awards,exemptions from entrance exams for postgraduate recommendations,and domestic or international further education,certain new issues have emerged in its practical application.These problems have hindered the effective functioning of the GPA system,attracting widespread attention.This paper examines the origin,connotation,and theoretical assumptions of the GPA system,discusses its positive functions and existing challenges,and proposes recommendations for further improving academic evaluation.
基金supported by the Humanities and Social Sciences Cultivation Fund Project of the USST(Grant No.24SKPY04)the China Youth and Children Research Association(Grant No.2023B18).
文摘Purpose:This study aims to address the lack of a unified grading framework in Chinese reading by proposing a comprehensive model integrating linguistic complexity and reading experience,to evaluate the difficulty level of Chinese books.Design/methodology/approach:We utilized the Probabilistic Fuzzy Linguistic Technique(PFLT)for subjective indicators related to reading experience.Combined with collected objective indicators data,the Entropy Weight Method(EWM)is used for objective weight allocation,and Tomada De Decisão Interativa Multicritério(TODIM)is applied for multi-criteria decision-making.Findings:The results demonstrate that the proposed framework significantly enhances the alignment between text complexity and reader engagement,achieving a high consistency with authoritative benchmarks.Research limitations:The study may be limited by the scope of subjective and objective indicators used;further validation with more diverse data sources could strengthen generalizability.Practical implications:This approach shows promise in advancing the standardization and objectivity of Chinese reading grading systems,with potential applications in educational and publishing contexts.Originality/value:This study offers a structured evaluation model that incorporates both linguistic complexity and experiential factors,providing a novel and comprehensive method for assessing Chinese text difficulty.
基金The Key Basic Program of Science and Technology Commission of Shanghai Municipality(No.08110511700)the ShanghaiLeading Academic Discipline Program(No.S30503)
文摘A multi-effect distillation technology for seawater desalination driven by tidal energy and low grade energy is presented.In the system,tidal energy is utilized to supply power instead of coventional electric pumps during the operation,resulting in the decrease of dependence on steady electric power supply and a reduction in the running costs.According to the technological principle,a testing unit is designed and built.The effects of the feed seawater temperature and the heat source temperature on the unit performance are tested and analyzed.The experimental results show that the fresh water output is 27 kg/h when the heating water temperature is 65 ℃ and the absolute pressure is 25 kPa.The experimental and theoretical analysis results indicate that the appropriate heating water temperature is a key factor in ensuring the steady operation of the system.
文摘The 3-dimensional couple equations of magneto-electro-elastic structures are derived under Hamiltonian system based on the Hamilton principle. The problem of single sort of variables is converted into the problem of double sorts of variables, and the Hamilton canonical equations are established. The 3-dimensional problem of magneto-electro-elastic structure which is investigated in Euclidean space commonly is converted into symplectic system. At the same time the Lagrange system is converted into Hamiltonian system. As an example, the dynamic characteristics of the simply supported functionally graded magneto-electro-elastic material （FGMM） plate and pipe are investigated. Finally, the problem is solved by symplectic algorithm. The results show that the physical quantities of displacement, electric potential and magnetic potential etc. change continuously at the interfaces between layers under the transverse pressure while some other physical quantities such as the stress, electric and magnetic displacement are not continuous. The dynamic stiffness is increased by the piezoelectric effect while decreased by the piezomagnetic effect.
基金This work was supported by the National Basic Research Program of China(No.2005CB623703)National Natural Science Foundation(No.5047405I)+1 种基金Hunan Provincial Natural Science Foundation of China(No.03JJY3080)Trans-Century Excellent Persons Cultivation Project of Ministry of Education of China(in 2002).
文摘The thermal stresses relaxation of Ni/NiFe2O4 system functionally graded cermet inert anode for aluminum electrolysis was optimally designed. The transient thermal stresses of the inert anode under complex boundary condition during high-temp （955℃） electrolysis were calculated using the finite-element software ANSYS, the influence of different parameters on the distribution of the thermal stresses were analyzed. The results showed that, during the process of thermal shock, the thermal hoop tensile stress on the surface of the anode is very large, which is possibly the major cause of anode crack; when the radius of the anode is between 0.05-0.15m, a range that can be realized by recent manufacturing technology, the optimum composition distribution exponent p is 0.25; The hoop tensile stresses reduce with the decrease of anode scale and also decrease with the decrease of the convection coefficient between the electrolyte and the anode.
文摘BACKGROUND Hepatocellular carcinoma(HCC)is a frequent cause of cancer related death globally.Neutrophil to lymphocyte ratio(NLR)and albumin bilirubin(ALBI)grade are emerging prognostic indicators in HCC.AIM To study published literature of NLR and ALBI over the last five years,and to validate NLR and ALBI locally in our centre as indicators of HCC survival.METHODS A systematic review of the published literature on PubMed of NLR and ALBI in HCC over the last five years.The search followed the guidelines of the preferred reporting items for systematic reviews and meta-analyses.Additionally,we also investigated HCC cases between December 2013 and December 2018 in our centre.RESULTS There were 54 studies describing the relation between HCC and NLR and 95 studies describing the relation between HCC and ALBI grade over the last five years.Our local cohort of patients showed NLR to have a significant negative relationship to survival(P=0.011).There was also significant inverse relationship between the size of the largest HCC nodule and survival(P=0.009).Median survival with alpha fetoprotein(AFP)<10 KU/L was 20 mo and with AFP>10 KU/L was 5 mo.We found that AFP was inversely related to survival,this relationship was not statically significant(P=0.132).Mean survival for ALBI grade 1 was 37.7 mo,ALBI grade 2 was 13.4 months and ALBI grade 3 was 4.5mo.ALBI grades performed better than Child Turcotte Pugh score in detecting death from HCC.CONCLUSION NLR and ALBI grade in HCC predict survival better than the conventional alpha fetoprotein.ALBI grade performs better than Child Turcotte Pugh score.These markers are done as part of routine clinical care and in cases of normal alpha fetoprotein,these markers could give a better understanding of the patient disease progression.NLR and ALBI grade could have a role in modified easier to learn staging and prognostic systems for HCC.
文摘Stream sediment geochemistry remains a versatile tool in exploration especially in regions where knowledge of the primary mineralization is lacking and the exploration activities are still at reconnaissance stage. In this study, we investigate the concentrations of gold and associated elements in stream sediment samples from the Vaimba-Lidi drainage system in northern Cameroon;a relatively remote area where alluvial gold is worked locally, and exploration activities are at early stage. The main river and its principal first and second order tributaries were sampled, panned for gold grain recovery and the 100 μm size fraction analyzed for Au by fire assay with Ni finish. A suite of other elements were analyzed for by inductively coupled plasma mass spectrometry (ICP-MS). Gold grades estimated by the panning and weighing technique rarely exceed1 g/t while the Au concentrations from chemical analysis range from 3.0 to 354.0 ppm. The spatial distribution of gold and all the other elements are presented as point symbol maps and the data analyzed using multivariate statistics. From the principal component analysis (PCA), the As-Mo-W-Ag as well as the Au-Zn factors point to the presence of primary hydrothermal gold-sulphide mineralization in the area and this can be further investigated. These results highlight the importance of multielement analysis and multivariate statistical interpretation of sediment geochemical data in inferring the nature of the underlying primary mineralization in any region.
文摘Coal has often been regarded as a problem additive to solve and improve the surface finish of iron castings,but at the same time causes other issues such as increased loss on ignition,total fines and moisture in system sands.Although many altermatives have been tried,there is no real substitute for thw all round properties of this wonderful natural resource.With the correct choice of coal,the combination of low ash,high volatile and swell index properties coupled with the key element of grading size,ensures castings are produced free from metal penetration and surface related problems.By careful selection,safe handling and processing coal continues to offer a good simple cost effective solution.Coal is subject to regulations in storage,processing and transportation and then further subjected to safe handling and use by the foundry.Despite these handicaps,it is still economical to the end user and modern processing and grading methods ensure it is used in the optimum condition to help produce quality castings.
文摘In this work,a novel approach of leaching valuable metals,such as niobium,yttrium and cerium,from a niobium-bearing ore of low grade by roasting KHSO_(4)-H_(2)SO_(4)system was experimentally studied.Through the work,the effects of roasting temperature,roasting time,mass ratio of agents to ore and the types of leaching agents on the extraction of Nb,Y and Ce were investigated,and the roasting KHSO_(4)-H_(2)SO_(4)-ore system was thought as an effective method to extract these valuable metals.It was found that the recovery of Nb,Y and Ce can,respectively,reach 90.20%,97.22%and 98.41%in condition of roasting temperature of 300℃,roasting time of 2 h,mass ratio of KHSO_(4)-to-H_(2)SO_(4)to ore of 0.5:1:1,particle size of-74 lm(~95%),leaching solution of oxalic acid(30 g·L^(-1)),leaching temperature of 90℃and leaching liquid-to-solid ratio of 5:1.The leaching kinetics of the calcined Nb-bearing ore in oxalic acid solution was successfully modeled by chemical reaction model,and the apparent activity energy was obtained to be14.16 kJ·mol^(-1).The results generated from this work will provide the fundamentals for extracting Nb,Y and Ce from a niobium-bearing ore of low grade and have potential applications value in future.
文摘In patients with high grade gliomas (HGGs), progression after treatment can be difficult to diagnose due to treatment-related effects, which overlap in appearance with tumour progression on conventional magnetic resonance imaging (MRI) sequences. Specialised imaging methods have been studied for this purpose, though most institutions currently use histopathology or clinicoradiological follow-up for diagnosis. This publication aims to review the evidence for perfusion MRI techniques. The databases of Pubmed, MEDLINE, EMBASE and Scopus were searched using combinations of the subject headings high grade glioma and MRI perfusion. 41 articles fulfilled the inclusion criteria. Dynamic Susceptibility Contrast (DSC) MRI was the most extensively studied, with several studies achieving high sensitivities and specificities. Other techniques exhibiting potential include Dynamic Contrast Enhanced (DCE) MRI, Arterial Spin Labelling (ASL). However, these techniques are not widely used or available for clinical practice. Composite measures combining results from multiple techniques tended to achieve higher accuracies. Some publications compared processing software used or looked at machine learning with relative success. An issue common to the literature is the lack of standardisation in the reference standard and acquisition/processing methods. Furthermore, many had small sample sizes, and further consideration needs to be given with regards to timing of imaging, and treatment regimens received in such studies.
基金Project supported by the National Natural Science Foundation of China(No.11972259)。
文摘Wrinkles in flat graded elastic layers have been recently described as a timevarying Hamiltonian system by the energy method.Cylindrical core/shell structures can also undergo surface instabilities under the external pressure.In this study,we show that by treating the radial direction as a pseudo-time variable,the graded core/shell system with radially decaying elastic properties can also be described within the symplectic framework.In combination with the shell buckling equation,the present paper addresses the surface wrinkling of graded core/shell structures subjected to the uniform external pressure by solving a series of ordinary differential equations with varying coefficients.Three representative gradient distributions are showcased,and the predicted critical pressure and critical wave number are verified by finite element simulations.The symplectic framework provides an efficient and accurate approach to understand the surface instability and morphological evolution in curved biological tissues and engineered structures.
文摘By virtue of a complete set of two displacement potentials,an analytical derivation of the elastostatic Green’s functions of an exponentially graded transversely isotropic substrate–coating system is presented.Three-dimensional point–load and patch–load Green’s functions for stresses and displacements are given in line-integral representations.The formulation includes a complete set of transformed stress–potential and displacement–potential relations,with utilizing Fourier series and Hankel transforms.As illustrations,the present Green’s functions are degenerated to the special cases such as an exponentially graded half-space and a homogeneous two-layered half-space Green’s functions.Because of complicated integrand functions,the integrals are evaluated numerically and for numerical computation of the integrals,a robust and effective methodology is laid out which gives the necessary account of the presence of singularities of integration.Comparisons of the existing numerical solutions for homogeneous two-layered isotropic and transversely isotropic half-spaces are made to confirm the accuracy of the present solutions.Some typical numerical examples are also given to show the general features of the exponentially graded two-layered half-space Green’s functions that the effect of degree of variation of material properties will be recognized.
基金Supported by NSFC(11301003,11426031,11501560)the Research Fund for Doctor Station of the Education Ministry of China(20123401120005)NSF of Anhui Province(1308085QA02)
文摘We consider the large time behavior of a non-autonomous third grade fluid sys- tem, which could be viewed as a perturbation of the classical Navier-Stokes system. Under proper assumptions, we firstly prove that the family of processes generated by the problem ad- mits a uniform attractor in the natural phase space. Then we prove the upper-semicontinuity of the uniform attractor when the perturbation tends to zero.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10804060)Higher Educational Science and Technology Program of Shandong Province of China (Grant No. J08LI05)
文摘This paper reports that SiO2 is selected to fabricate broadband antireflection （AR） coatings on fused silica substrate by using glancing angle deposition and physical vapour deposition. Through accurate control of the graded index of the SiO2 layer, transmittance of thc graded broadband AR coating can achieve an average value of 98% across a spectral range of 300-1850 nm. Moreover, a laser-induced damage threshold measurement of the fabricated AR coating is performed by using a one-on-one protocol according to ISOl1254-1, resulting in an average damage threshold of 17.2 J/cm2.
基金supported by the National Key Research and Development Program of China(No.2020YFA0711700)the National Natural Science Foundation of China(No.12322206,No.52378158,No.12302205)ZJU-ZCCC Institute of Collaborative Innovation(No.ZDJG2021002).
文摘In this paper,a multiscale model is developed for the mass functionally graded(FG)beam-fluid system to investigate its static and dynamic responses based on 3D printed porous beam free vibration tests,which are determined by two aspects.At the microstructural level,the gradient variation is realized by arbitrary distribution of matrix pores,and the effective moduli under specific distribution are obtained using the micromechanics homogenization theory.In the meantime,at the structural level,the mechanical responses of FG porous beams subjected to mass loading are considered in a static fluid environment.Then,the explicit expressions of local finite-element(FE)expressions corresponding to the static and dynamic responses are given in the appendices.The present results are validated against numerical and experimental results from the literature and mechanical tests of 3D printed structures,with good agreement generally obtained,giving credence to the present model.On this basis,a comprehensive parametric study is carried out,with a particular focus on the effects of boundary conditions,fluid density,and slenderness ratio on the bending and vibration of FG beams with several different gradations.
文摘The availability of automated evaluation methodologies that may reliably be used for determining students’ scholastic performance through assigning letter grades are of utmost practical importance to educators, students, and do invariably have pivotal values to all stakeholders of the academic process. In particular, educators use letter grades as quantification metrics to monitor students’ intellectual progress within a framework of clearly specified learning objectives of a course. To students grades may be used as predictive measures and motivating drives for success in a study field. However due to numerous objective and subjective variables that may by be accounted for in a methodological process of assigning students’ grades, and since such a process is often tainted with personal philosophy and human psychology factors, it is essential that educators exercise extra care in maximizing positive account of all objective factors and minimizing negative ramifications of subjectively fuzzy factors. To this end, and in an attempt to make assigning students’ grades more reliable for assessing true-level of mastering specified learning outcomes, this paper will: i) provide a literature review on previous works on the most common methods that have traditionally been in use for assigning students’ grades, and a short account of the virtues and/or vices of such methods, and ii) present a user-friendly computer code that may be easily adapted for the purpose of assigning students’ grades. This would relieve educators from the overwhelming concerns associated with mechanistic aspects of determining educational metrics, and it would allow them to have more time and focus to obtain reliable assessments of true-level of students’ mastery of learning outcomes by accounting for all possible evaluation components.
