Taking 14 prefecture-level cities in Guangxi as an object,this paper explored the difference of cultivated land utilization efficiency in Guangxi,comprehensively evaluated the economic,social,and ecological aspects,an...Taking 14 prefecture-level cities in Guangxi as an object,this paper explored the difference of cultivated land utilization efficiency in Guangxi,comprehensively evaluated the economic,social,and ecological aspects,and analyzed the regional differences in cultivated land use efficiency in Guangxi from 2005 to 2018 based on the improved TOPSIS method.By studying the quantitative change trends and spatial differences of the utilization benefit of cultivated land resources in Guangxi,it came up with recommendations for optimizing the allocation of cultivated land from the quantity and quality of cultivated land.It is intended to provide a scientific and theoretical reference for improving the use efficiency of cultivated land in Guangxi.展开更多
In this paper, an improved splitting method, based on the completely square-conservative explicit difference schemes, is established. Not only can the time-direction precision of this method be higher than that of the...In this paper, an improved splitting method, based on the completely square-conservative explicit difference schemes, is established. Not only can the time-direction precision of this method be higher than that of the traditional splitting methods but also can the physical feature of mutual dependence of the fast and the slow stages that are calculated separately and splittingly be kept as well. Moreover, the method owns an universality, it can be generalized to other square-conservative difference schemes, such as the implicit and complete ones and the explicit and instantaneous ones. Good time benefits can be acquired when it is applied in the numerical simulations of the monthly mean currents of the South China Sea.展开更多
Cancer staging detection is important for clinician to assess the patients' status and make optimal therapy decision. In this study, the machine learning algorithm based on principal component analysis(PCA) and su...Cancer staging detection is important for clinician to assess the patients' status and make optimal therapy decision. In this study, the machine learning algorithm based on principal component analysis(PCA) and support vector machine(SVM) was combined with urine surface-enhanced Raman scattering(SERS) spectroscopy for improving the identification of colorectal cancer(CRC) at early and advanced stages. Two discriminant methods, linear discriminant analysis(LDA) and SVM were compared, and the results indicated that the diagnostic accuracy of SVM(93.65%) was superior to that of LDA(80.95%). This exploratory study demonstrated the great promise of urine SERS spectra along with PCA-SVM for facilitating more accurate detection of CRC at different stages.展开更多
For oil pipeline in mountain areas,high hydrostatic pressure in the pipeline may cause error-opening of pressure relief valves,and oil is discharged from the pipeline to the pressure relief tanks,bringing spilling-ove...For oil pipeline in mountain areas,high hydrostatic pressure in the pipeline may cause error-opening of pressure relief valves,and oil is discharged from the pipeline to the pressure relief tanks,bringing spilling-over risk of the pressure relief tanks.Therefore,simulating the error-opening situations of the pressure relief valves and investigating the oil discharge process are necessary for checking the possibility of the spilling-over accident and then proposing measures to improve the pressure relief system.This research focuses on a continuous undulating oil pipeline with large elevation difference and a station along this pipeline,which is named B station in this paper,is studied.By OLGA software,simulation model of the pressure relief system of B station is established,and the accuracy of the model is verified by reconstructing a real accident and making a comparison with the actual accident data.The maximum discharge rate reached 8284 m3/h when the pressure relief valve was opened by mistake in the inlet and outlet of the station.The accumulated filling time of the two pressure relief tanks is 200 s,which is in good agreement with the accident data.On this basis,for error-opening of the pressure relief valves at the inlet and outlet of B station,simulation is performed to investigate variations of the discharge velocity,discharge flow rate,accumulated discharge volume and ventilation volume of the vent valve.The discharge velocity is found to be over the maximum velocity allowed for safety consideration.According to the accumulated discharge volume,it is inferred that spilling over of the pressure relief tanks will be caused once error-opening of the pressure relief valve occurs.Also it is judged that the existing breathing valve can not satisfy the ventilation requirement in case of failure of the pressure relief valves.From these simulation results,it is proposed that increasing the number of vent valves,replacing the manual valves with electrically operated valves,and employing security control interlock protection program are improvement measures to guarantee safe,efficient and reliable operation of the pressure relief system at B station.展开更多
新型电力系统下,大量新能源电源及电力电子设备接入交流电网。发生母线区内故障时,受控制策略影响,故障电流幅值受控,角度受控,谐波含量高,母线比率差动保护的动作性能下降,因此文中提出一种适用于新型电力系统的母线比率差动保护改进...新型电力系统下,大量新能源电源及电力电子设备接入交流电网。发生母线区内故障时,受控制策略影响,故障电流幅值受控,角度受控,谐波含量高,母线比率差动保护的动作性能下降,因此文中提出一种适用于新型电力系统的母线比率差动保护改进算法。首先,介绍传统比率差动算法的基本原理,并分析新型电力系统下该算法存在的问题;然后,提出不受故障电流角差及谐波影响的母线比率差动保护改进算法,将相位存在差异的各支路电流相量映射到同一坐标系下,并进行差流和制动电流计算,分析母线比率差动保护改进算法在母线区内外故障及区外故障电流互感器(current transformer,CT)饱和时的动作性能,提出母线比率差动保护改进逻辑;最后,基于实时数字仿真(real time digital simulation,RTDS),对比传统比率差动保护和改进比率差动保护的动作性能,证明改进比率差动保护能够在不降低保护动作可靠性的前提下提高动作灵敏性。展开更多
目的:探讨分析不同平面腮腺浅叶良性肿瘤选择相应平面的改良小切口的应用效果。方法:选取笔者医院2021年6月-2023年3月收治的86例腮腺浅叶良性肿瘤切除术患者。将32例根据肿瘤所在的平面而选择对应平面的改良小切口患者作为观察组,将19...目的:探讨分析不同平面腮腺浅叶良性肿瘤选择相应平面的改良小切口的应用效果。方法:选取笔者医院2021年6月-2023年3月收治的86例腮腺浅叶良性肿瘤切除术患者。将32例根据肿瘤所在的平面而选择对应平面的改良小切口患者作为观察组,将19例选择非肿瘤所在平面的对应平面改良小切口作为对照1组。比较两组患者术中及术后指标,并发症及复发率情况;此外,将35例传统“S”形切口患者作为对照2组,记录术后10 d两组视觉模拟评分(Visual Analog Scale,VAS)、术后3个月患者和观察者瘢痕评估量(Patient and Observerscarass Ment Scale,POSAS)评分情况以及术后6个月两组患者审美满意度评价。结果:86例患者手术均顺利完成。观察组较对照1组手术时间、术中出血量及术后引流量少,差异有统计学意义(P<0.05);术后并发症总发生率观察组低于对照1组,差异有统计学意义(P<0.05);术后6个月,观察组与对照1组复发率差异无统计学意义(P>0.05);术后10 d,观察组VAS评分高于对照2组,差异有统计学意义(P<0.05);术后3个月,观察组POSAS评分高于对照2组(P<0.05);术后6个月,观察组术后审美满意度评价较对照2组高(P<0.05)。结论:筛选腮腺浅叶区域不同层面的良性肿瘤,采用所在层面的改良小切口进行切除,其临床效果是可行的、安全的,手术时间更短,产生并发症较少,切口恢复更快,可以达到更好的美容效果;同时提出根据腮腺浅叶“三分法”来设计切口,为临床医生在腮腺肿瘤术中提供了更灵活的小切口设计思路。展开更多
BACKGROUND The minimal clinically important difference(MCID)is defined as the smallest meaningful change in a health domain that a patient would identify as important.Thus,an improvement that exceeds the MCID can be u...BACKGROUND The minimal clinically important difference(MCID)is defined as the smallest meaningful change in a health domain that a patient would identify as important.Thus,an improvement that exceeds the MCID can be used to define a successful treatment for the individual patient.AIM To quantify the rate of clinical improvement following anatomical total shoulder arthroplasty for glenohumeral osteoarthritis.METHODS Patients were treated with the Global Unite total shoulder platform arthroplasty between March 2017 and February 2019 at Herlev and Gentofte Hospital,Denmark.The patients were evaluated preoperatively and 3 months,6 months,12 months,and 24 months postoperatively using the Western Ontario Osteoarthritis of the Shoulder index(WOOS),Oxford Shoulder Score(OSS)and Constant-Murley Score(CMS).The rate of clinically relevant improvement was defined as the proportion of patients who had an improvement 24 months postoperatively that exceeded the MCID.Based on previous literature,MCID for WOOS,OSS,and CMS were defined as 12.3,4.3,and 12.8 respectively.RESULTS Forty-nine patients with a Global Unite total shoulder platform arthroplasty were included for the final analysis.Mean age at the time of surgery was 66 years(range 49.0-79.0,SD:8.3)and 65%were women.One patient was revised within the two years follow-up.The mean improvement from the preoperative assessment to the two-year follow-up was 46.1 points[95%confidence interval(95%CI):39.7-53.3,P<0.005]for WOOS,18.2 points(95%CI:15.5-21.0,P<0.005)for OSS and 37.8 points(95%CI:31.5-44.0,P<0.005)for CMS.Two years postoperatively,41 patients(87%)had an improvement in WOOS that exceeded the MCID,45 patients(94%)had an improvement in OSS that exceeded the MCID,and 42 patients(88%)had an improvement in CMS that exceeded the MCID.CONCLUSION Based on three shoulder-specific outcome measures we find that approximately 90%of patients has a clinically relevant improvement.This is a clear message when informing patients about their prognosis.展开更多
This paper aims to help students who study English as a second language improve reading skills. Based on the reading theoretical foundation, some problems which often encountered during the process of reading will be ...This paper aims to help students who study English as a second language improve reading skills. Based on the reading theoretical foundation, some problems which often encountered during the process of reading will be discussed. Finally, a conclusion as to how to solve these problems will be made.展开更多
基金Youth Program of Humanities and Social Science Project of the Ministry of Education(17YJC79004)Program of National Natural Science Foundation of China(71803104)Qingchuang Science and Technology Support Plan for Colleges and Universities in Shandong Province(2019RWE009).
文摘Taking 14 prefecture-level cities in Guangxi as an object,this paper explored the difference of cultivated land utilization efficiency in Guangxi,comprehensively evaluated the economic,social,and ecological aspects,and analyzed the regional differences in cultivated land use efficiency in Guangxi from 2005 to 2018 based on the improved TOPSIS method.By studying the quantitative change trends and spatial differences of the utilization benefit of cultivated land resources in Guangxi,it came up with recommendations for optimizing the allocation of cultivated land from the quantity and quality of cultivated land.It is intended to provide a scientific and theoretical reference for improving the use efficiency of cultivated land in Guangxi.
基金Partly supported by the State Major Key Project for Basic Researches
文摘In this paper, an improved splitting method, based on the completely square-conservative explicit difference schemes, is established. Not only can the time-direction precision of this method be higher than that of the traditional splitting methods but also can the physical feature of mutual dependence of the fast and the slow stages that are calculated separately and splittingly be kept as well. Moreover, the method owns an universality, it can be generalized to other square-conservative difference schemes, such as the implicit and complete ones and the explicit and instantaneous ones. Good time benefits can be acquired when it is applied in the numerical simulations of the monthly mean currents of the South China Sea.
基金supported by the National Natural Science Foundation of China (No.61975031)the Natural Science Foundation of Fujian Province (No.2020J011121)+3 种基金the Product-University Cooperation Project of Fujian Province (No.2020Y4006)the National Clinical Key Specialty Construction Program (No.2021)the Fujian Provincial Clinical Research Center for Cancer Radiotherapy and Immunotherapy (No.2020Y2012)the Joint Funds for the Innovation of Science and Technology of Fujian Province (No.2021Y9192)。
文摘Cancer staging detection is important for clinician to assess the patients' status and make optimal therapy decision. In this study, the machine learning algorithm based on principal component analysis(PCA) and support vector machine(SVM) was combined with urine surface-enhanced Raman scattering(SERS) spectroscopy for improving the identification of colorectal cancer(CRC) at early and advanced stages. Two discriminant methods, linear discriminant analysis(LDA) and SVM were compared, and the results indicated that the diagnostic accuracy of SVM(93.65%) was superior to that of LDA(80.95%). This exploratory study demonstrated the great promise of urine SERS spectra along with PCA-SVM for facilitating more accurate detection of CRC at different stages.
文摘For oil pipeline in mountain areas,high hydrostatic pressure in the pipeline may cause error-opening of pressure relief valves,and oil is discharged from the pipeline to the pressure relief tanks,bringing spilling-over risk of the pressure relief tanks.Therefore,simulating the error-opening situations of the pressure relief valves and investigating the oil discharge process are necessary for checking the possibility of the spilling-over accident and then proposing measures to improve the pressure relief system.This research focuses on a continuous undulating oil pipeline with large elevation difference and a station along this pipeline,which is named B station in this paper,is studied.By OLGA software,simulation model of the pressure relief system of B station is established,and the accuracy of the model is verified by reconstructing a real accident and making a comparison with the actual accident data.The maximum discharge rate reached 8284 m3/h when the pressure relief valve was opened by mistake in the inlet and outlet of the station.The accumulated filling time of the two pressure relief tanks is 200 s,which is in good agreement with the accident data.On this basis,for error-opening of the pressure relief valves at the inlet and outlet of B station,simulation is performed to investigate variations of the discharge velocity,discharge flow rate,accumulated discharge volume and ventilation volume of the vent valve.The discharge velocity is found to be over the maximum velocity allowed for safety consideration.According to the accumulated discharge volume,it is inferred that spilling over of the pressure relief tanks will be caused once error-opening of the pressure relief valve occurs.Also it is judged that the existing breathing valve can not satisfy the ventilation requirement in case of failure of the pressure relief valves.From these simulation results,it is proposed that increasing the number of vent valves,replacing the manual valves with electrically operated valves,and employing security control interlock protection program are improvement measures to guarantee safe,efficient and reliable operation of the pressure relief system at B station.
文摘新型电力系统下,大量新能源电源及电力电子设备接入交流电网。发生母线区内故障时,受控制策略影响,故障电流幅值受控,角度受控,谐波含量高,母线比率差动保护的动作性能下降,因此文中提出一种适用于新型电力系统的母线比率差动保护改进算法。首先,介绍传统比率差动算法的基本原理,并分析新型电力系统下该算法存在的问题;然后,提出不受故障电流角差及谐波影响的母线比率差动保护改进算法,将相位存在差异的各支路电流相量映射到同一坐标系下,并进行差流和制动电流计算,分析母线比率差动保护改进算法在母线区内外故障及区外故障电流互感器(current transformer,CT)饱和时的动作性能,提出母线比率差动保护改进逻辑;最后,基于实时数字仿真(real time digital simulation,RTDS),对比传统比率差动保护和改进比率差动保护的动作性能,证明改进比率差动保护能够在不降低保护动作可靠性的前提下提高动作灵敏性。
文摘目的:探讨分析不同平面腮腺浅叶良性肿瘤选择相应平面的改良小切口的应用效果。方法:选取笔者医院2021年6月-2023年3月收治的86例腮腺浅叶良性肿瘤切除术患者。将32例根据肿瘤所在的平面而选择对应平面的改良小切口患者作为观察组,将19例选择非肿瘤所在平面的对应平面改良小切口作为对照1组。比较两组患者术中及术后指标,并发症及复发率情况;此外,将35例传统“S”形切口患者作为对照2组,记录术后10 d两组视觉模拟评分(Visual Analog Scale,VAS)、术后3个月患者和观察者瘢痕评估量(Patient and Observerscarass Ment Scale,POSAS)评分情况以及术后6个月两组患者审美满意度评价。结果:86例患者手术均顺利完成。观察组较对照1组手术时间、术中出血量及术后引流量少,差异有统计学意义(P<0.05);术后并发症总发生率观察组低于对照1组,差异有统计学意义(P<0.05);术后6个月,观察组与对照1组复发率差异无统计学意义(P>0.05);术后10 d,观察组VAS评分高于对照2组,差异有统计学意义(P<0.05);术后3个月,观察组POSAS评分高于对照2组(P<0.05);术后6个月,观察组术后审美满意度评价较对照2组高(P<0.05)。结论:筛选腮腺浅叶区域不同层面的良性肿瘤,采用所在层面的改良小切口进行切除,其临床效果是可行的、安全的,手术时间更短,产生并发症较少,切口恢复更快,可以达到更好的美容效果;同时提出根据腮腺浅叶“三分法”来设计切口,为临床医生在腮腺肿瘤术中提供了更灵活的小切口设计思路。
文摘BACKGROUND The minimal clinically important difference(MCID)is defined as the smallest meaningful change in a health domain that a patient would identify as important.Thus,an improvement that exceeds the MCID can be used to define a successful treatment for the individual patient.AIM To quantify the rate of clinical improvement following anatomical total shoulder arthroplasty for glenohumeral osteoarthritis.METHODS Patients were treated with the Global Unite total shoulder platform arthroplasty between March 2017 and February 2019 at Herlev and Gentofte Hospital,Denmark.The patients were evaluated preoperatively and 3 months,6 months,12 months,and 24 months postoperatively using the Western Ontario Osteoarthritis of the Shoulder index(WOOS),Oxford Shoulder Score(OSS)and Constant-Murley Score(CMS).The rate of clinically relevant improvement was defined as the proportion of patients who had an improvement 24 months postoperatively that exceeded the MCID.Based on previous literature,MCID for WOOS,OSS,and CMS were defined as 12.3,4.3,and 12.8 respectively.RESULTS Forty-nine patients with a Global Unite total shoulder platform arthroplasty were included for the final analysis.Mean age at the time of surgery was 66 years(range 49.0-79.0,SD:8.3)and 65%were women.One patient was revised within the two years follow-up.The mean improvement from the preoperative assessment to the two-year follow-up was 46.1 points[95%confidence interval(95%CI):39.7-53.3,P<0.005]for WOOS,18.2 points(95%CI:15.5-21.0,P<0.005)for OSS and 37.8 points(95%CI:31.5-44.0,P<0.005)for CMS.Two years postoperatively,41 patients(87%)had an improvement in WOOS that exceeded the MCID,45 patients(94%)had an improvement in OSS that exceeded the MCID,and 42 patients(88%)had an improvement in CMS that exceeded the MCID.CONCLUSION Based on three shoulder-specific outcome measures we find that approximately 90%of patients has a clinically relevant improvement.This is a clear message when informing patients about their prognosis.
文摘This paper aims to help students who study English as a second language improve reading skills. Based on the reading theoretical foundation, some problems which often encountered during the process of reading will be discussed. Finally, a conclusion as to how to solve these problems will be made.
