The California bearing ratio (CBR) test is the most widely spread method of determining the bearing strength of the pavement material and is fundamental to pavement design practice in most countries. This test is expe...The California bearing ratio (CBR) test is the most widely spread method of determining the bearing strength of the pavement material and is fundamental to pavement design practice in most countries. This test is expensive, laborious and time consuming, and to overcome this, Quasi static cone penetrometer machine was fabricated and used to measure the consistency limits (liquid limit-LL, Plastic limit-PL and Plasticity index-PI), which were used to develop an empirical equation to determine CBR. Soil samples were collected and unsoaked CBR, PL, LL and PI were determined according to BS 1377 part 9 and BS 1377-2;1990. Quasi static penetration forces at 20 mm depth of penetration were also determined at consistency limits. It was found that the force of 1020 gf and 60 gf was achieved at a depth of 20 mm at PI and LL respectively. The correlation and regression analysis between consistency limits, and the experimental CBR obtained showed coefficient of determination, R<sup>2</sup> = 0.907 between CBR and all the parameters using multiple linear regression analysis (MLRA). The regression equation developed was used together with the relationship developed between the Quasi static Penetration force at consistency limits and the tested consistency limits to come up with the General Empirical Equation. Verification of the formula showed that the correlation can be used accurately to determine the un soaked CBR.展开更多
为探究静磁场辅助冷冻(static magnetic field assisted freezing,SMAF)对牛肉品质的影响,采用不同强度SMAF(0、2、4、6、8、10 mT,-18℃),对比分析冷冻参数对牛背最长肌品质的影响。结果表明:与对照组相比,SMAF-6、8、10处理组相变时...为探究静磁场辅助冷冻(static magnetic field assisted freezing,SMAF)对牛肉品质的影响,采用不同强度SMAF(0、2、4、6、8、10 mT,-18℃),对比分析冷冻参数对牛背最长肌品质的影响。结果表明:与对照组相比,SMAF-6、8、10处理组相变时间分别显著缩短15%、25%和6.7%(P<0.05);SMAF处理有效提高了肌肉的持水性(解冻损失率、蒸煮损失率和离心损失率),降低了样品的ΔE(P<0.05),但对样品的pH值和硫代巴比妥酸反应物值无显著影响(P>0.05);此外,剪切力与肌原纤维小片化指数的结果一致,SMAF处理维持了牛肉的剪切力;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示,SMAF处理可以减少肉品经冷冻-解冻后蛋白质含量的降低。综上,在适当的静磁场强度下辅助冷冻,可节省冻结时间,提高肌肉持水力,减少蛋白质含量的降低,从而改善牛肉品质,其中SMAF-8处理效果最佳。展开更多
集中送出的新能源场站大多位于电网末端,随着其有功出力的增加,易出现静态电压失稳。该文将传统的阻抗模指标的应用对象由负荷推广至新能源场站,丰富了该指标在静态电压稳定评估方面的适用性场景,包括含无功补偿的新能源系统、新能源集...集中送出的新能源场站大多位于电网末端,随着其有功出力的增加,易出现静态电压失稳。该文将传统的阻抗模指标的应用对象由负荷推广至新能源场站,丰富了该指标在静态电压稳定评估方面的适用性场景,包括含无功补偿的新能源系统、新能源集群馈入系统、以及新能源多机多馈入系统。具体地,首先,分析新能源单馈入系统的临界静态电压稳定条件,并据此给出用于评估新能源场站静态电压稳定性的阻抗模裕度指标及稳定判据;其次,通过将无功补偿设备并入系统阻抗,分析无功补偿对于指标的影响;再次,证明在新能源的集群馈入系统中,公共耦合点(point of common coupling,PCC)的电压失稳将发生在单个新能源场站之前,并据此确定PCC点作为指标的计算节点;之后,为考虑多机多馈入系统中不同新能源场站间的影响,在指标的计算过程中,保留待评估的关键新能源场站,将其他新能源场站等值为阻抗,并入节点阻抗矩阵中,实现方法在多机多馈入系统中的扩展应用。最后,基于PSD-BPA中建立的单机单馈入系统、多机多馈入系统、以及某省实际大电网算例验证指标的有效性。展开更多
Due to low viscosity of seawater,it is difficult to form a seawater-lubricated film.It is easy to cause the overload and burning phenomenon of seawater-lubrication sliding bearing,and then the operation stability and ...Due to low viscosity of seawater,it is difficult to form a seawater-lubricated film.It is easy to cause the overload and burning phenomenon of seawater-lubrication sliding bearing,and then the operation stability and service life can be shortened seriously.Therefore,the paper introduces an electromagnetic suspension theory into the seawater lubricated sliding bearing.Then a novel magnetic-liquid double suspension bearing can be formed,which can enhance bearing capacity and stiffness greatly.Firstly,the structural characteristics,support-adjustment mechanism of magnetic-liquid double suspension bearing is analyzed.Secondly,based on force balance equation,electromagnetic equation and flow equation,the transfer functions of single DOF bearing system of magnetic-liquid double suspension bearing under constant-flow supply model are deduced.Then bearing capacity,static stiffness and total power loss are selected as static performance indexes.The influence rule of operaton and structural parameters on the static performance of single DOF bearing system will be analyzed.The results show that bearing capacity decreases with the increase of liquid film thickness and width of edge seals,bias current and coil turns decrease.Static stiffness decreases with the increase of liquid film thickness,edge seals width,bias current and coil turns.Total power loss decreases with the increase of liquid film thickness,edge seals width,bias current and coil turns decrease.And static performance indexes can not be affected by liquid viscosity.The proposed research provides some theoretical and experimental basis for the parameter design of magnetic-liquid double suspension bearing.展开更多
The Android platform is the most popular mobile operating system.With the increase of the number of Android users,a lot of security issues have occurred.In order to detect the malicious behaviors for the installed And...The Android platform is the most popular mobile operating system.With the increase of the number of Android users,a lot of security issues have occurred.In order to detect the malicious behaviors for the installed Android Apps,in this paper,we propose an Android malware detecting scheme by integrating static and dynamic analysis methods.We use Androguard and Droid Box to extract the features,and then remove the irrelevant features.Then we employ the support vector machine（SVM） to classify the Android malware and benignware.From the result of our proposed scheme,the proposed integrated static and dynamic analysis scheme with SVM can effectively detect the Android malware.展开更多
文摘The California bearing ratio (CBR) test is the most widely spread method of determining the bearing strength of the pavement material and is fundamental to pavement design practice in most countries. This test is expensive, laborious and time consuming, and to overcome this, Quasi static cone penetrometer machine was fabricated and used to measure the consistency limits (liquid limit-LL, Plastic limit-PL and Plasticity index-PI), which were used to develop an empirical equation to determine CBR. Soil samples were collected and unsoaked CBR, PL, LL and PI were determined according to BS 1377 part 9 and BS 1377-2;1990. Quasi static penetration forces at 20 mm depth of penetration were also determined at consistency limits. It was found that the force of 1020 gf and 60 gf was achieved at a depth of 20 mm at PI and LL respectively. The correlation and regression analysis between consistency limits, and the experimental CBR obtained showed coefficient of determination, R<sup>2</sup> = 0.907 between CBR and all the parameters using multiple linear regression analysis (MLRA). The regression equation developed was used together with the relationship developed between the Quasi static Penetration force at consistency limits and the tested consistency limits to come up with the General Empirical Equation. Verification of the formula showed that the correlation can be used accurately to determine the un soaked CBR.
基金Projects(52208392,52068044)supported by the National Natural Science Foundation of ChinaProject(2021M693843)supported by the China Postdoctoral Science Foundation+1 种基金Project(21RJ7RA309)supported by Natural Science Foundation of Gansu Province,ChinaProject(1520260306)supported by Tianyou Youth Talent Lift Program of Lanzhou Jiaotong University,China。
文摘为探究静磁场辅助冷冻(static magnetic field assisted freezing,SMAF)对牛肉品质的影响,采用不同强度SMAF(0、2、4、6、8、10 mT,-18℃),对比分析冷冻参数对牛背最长肌品质的影响。结果表明:与对照组相比,SMAF-6、8、10处理组相变时间分别显著缩短15%、25%和6.7%(P<0.05);SMAF处理有效提高了肌肉的持水性(解冻损失率、蒸煮损失率和离心损失率),降低了样品的ΔE(P<0.05),但对样品的pH值和硫代巴比妥酸反应物值无显著影响(P>0.05);此外,剪切力与肌原纤维小片化指数的结果一致,SMAF处理维持了牛肉的剪切力;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳结果显示,SMAF处理可以减少肉品经冷冻-解冻后蛋白质含量的降低。综上,在适当的静磁场强度下辅助冷冻,可节省冻结时间,提高肌肉持水力,减少蛋白质含量的降低,从而改善牛肉品质,其中SMAF-8处理效果最佳。
文摘集中送出的新能源场站大多位于电网末端,随着其有功出力的增加,易出现静态电压失稳。该文将传统的阻抗模指标的应用对象由负荷推广至新能源场站,丰富了该指标在静态电压稳定评估方面的适用性场景,包括含无功补偿的新能源系统、新能源集群馈入系统、以及新能源多机多馈入系统。具体地,首先,分析新能源单馈入系统的临界静态电压稳定条件,并据此给出用于评估新能源场站静态电压稳定性的阻抗模裕度指标及稳定判据;其次,通过将无功补偿设备并入系统阻抗,分析无功补偿对于指标的影响;再次,证明在新能源的集群馈入系统中,公共耦合点(point of common coupling,PCC)的电压失稳将发生在单个新能源场站之前,并据此确定PCC点作为指标的计算节点;之后,为考虑多机多馈入系统中不同新能源场站间的影响,在指标的计算过程中,保留待评估的关键新能源场站,将其他新能源场站等值为阻抗,并入节点阻抗矩阵中,实现方法在多机多馈入系统中的扩展应用。最后,基于PSD-BPA中建立的单机单馈入系统、多机多馈入系统、以及某省实际大电网算例验证指标的有效性。
基金Support by the National Natural Science Foundation of China(No.51705445)the Open Project Funding of Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Controlthe Open Project Funding of Jiangsu Provincial Key Laboratory of Advanced Manufacture and Process for Marine Mechanical Equipment
文摘Due to low viscosity of seawater,it is difficult to form a seawater-lubricated film.It is easy to cause the overload and burning phenomenon of seawater-lubrication sliding bearing,and then the operation stability and service life can be shortened seriously.Therefore,the paper introduces an electromagnetic suspension theory into the seawater lubricated sliding bearing.Then a novel magnetic-liquid double suspension bearing can be formed,which can enhance bearing capacity and stiffness greatly.Firstly,the structural characteristics,support-adjustment mechanism of magnetic-liquid double suspension bearing is analyzed.Secondly,based on force balance equation,electromagnetic equation and flow equation,the transfer functions of single DOF bearing system of magnetic-liquid double suspension bearing under constant-flow supply model are deduced.Then bearing capacity,static stiffness and total power loss are selected as static performance indexes.The influence rule of operaton and structural parameters on the static performance of single DOF bearing system will be analyzed.The results show that bearing capacity decreases with the increase of liquid film thickness and width of edge seals,bias current and coil turns decrease.Static stiffness decreases with the increase of liquid film thickness,edge seals width,bias current and coil turns.Total power loss decreases with the increase of liquid film thickness,edge seals width,bias current and coil turns decrease.And static performance indexes can not be affected by liquid viscosity.The proposed research provides some theoretical and experimental basis for the parameter design of magnetic-liquid double suspension bearing.
基金partially supported by MOST under Grant No.105-2221-E-327-036
文摘The Android platform is the most popular mobile operating system.With the increase of the number of Android users,a lot of security issues have occurred.In order to detect the malicious behaviors for the installed Android Apps,in this paper,we propose an Android malware detecting scheme by integrating static and dynamic analysis methods.We use Androguard and Droid Box to extract the features,and then remove the irrelevant features.Then we employ the support vector machine（SVM） to classify the Android malware and benignware.From the result of our proposed scheme,the proposed integrated static and dynamic analysis scheme with SVM can effectively detect the Android malware.
