A systematic method is developed to studY the classical motion of a mass point in gravitational gauge field. First, by using Mathematica, a spherical symmetric solution of the field equation of gravitational gauge fie...A systematic method is developed to studY the classical motion of a mass point in gravitational gauge field. First, by using Mathematica, a spherical symmetric solution of the field equation of gravitational gauge field is obtained, which is just the traditional Schwarzschild solution. Combining the principle of gauge covariance and Newton＇s second law of motion, the equation of motion of a mass point in gravitational field is deduced. Based on the spherical symmetric solution of the field equation and the equation of motion of a mass point in gravitational field, we can discuss classical tests of gauge theory of gravity, including the deflection of light by the sun, the precession of the perihelia of the orbits of the inner planets and the time delay of radar echoes passing the sun. It is found that the theoretical predictions of these classical tests given by gauge theory of gravity are completely the same as those given by general relativity.展开更多
It is known that the strength of concrete is seriously affected by damage and cracking. In this paper, six concrete samples under different damage levels are studied. The experimental results show a linear dependence ...It is known that the strength of concrete is seriously affected by damage and cracking. In this paper, six concrete samples under different damage levels are studied. The experimental results show a linear dependence of the resonance frequency shift on strain amplitude at the fundamental frequency, and approximate quadratic dependence of the am- plitudes of the second and third harmonics on strain amplitude at the fundamental frequency as well. In addition, the amplitude of the third harmonics is shown to increase with the increase of damage level, which is even higher than that of the second harmonics in samples with higher damage levels. These are three properties of non-classical nonlinear acoustics. The nonlinear parameters increase from 106 to 108 with damage level, and are more sensitive to the damage level of the concrete than the linear parameters obtained by using traditional acoustics methods. So, this method based on non-classical nonlinear acoustics may provide a better means of non-destructive testing （NDT） of concrete and other porous materials.展开更多
目的:汉化冠心病患者运动恐惧量表(Fear of Activity in Patients with Coronary Artery Disease,Fact-CAD),为国内冠心病患者运动恐惧的评估提供科学、可靠的特异性工具。方法:遵循Brislin翻译模型对量表进行翻译、回译和文化调适,形...目的:汉化冠心病患者运动恐惧量表(Fear of Activity in Patients with Coronary Artery Disease,Fact-CAD),为国内冠心病患者运动恐惧的评估提供科学、可靠的特异性工具。方法:遵循Brislin翻译模型对量表进行翻译、回译和文化调适,形成中文版Fact-CAD量表。于2022年10月至2023年2月,采用便利抽样法,选取杭州市某三级甲等医院的334例冠心病患者进行调查,结合Rasch模型分析和经典测量理论对问卷的信度、效度进行评价。结果:中文版Fact-CAD为单维度,包括19个条目。各条目的未加权均方拟合统计量值为0.72~2.10,加权均方拟合统计量为0.88~1.29,条目-总分的相关系数为0.04~0.58,各条目拟合结果符合Rasch模型。以中文版多维度运动自我效能量表作为聚合效度指标,相关系数为-0.636(P<0.01),量表平均内容效度指数为0.951。总量表的Cronbach’sα系数为0.901,Guttman折半信度为0.885,重测信度为0.893。结论:中文版Fact-CAD具有良好的信度、效度,量表条目少,评估时间短,难度适中,适用于我国冠心病患者运动恐惧的评估。展开更多
目的应用经典测量理论(classical test theory,CTT)和项目反应理论(item response theory,IRT)对慢性肺源性心脏病生命质量测定量表[QLICD-CPHD(V2.0)]进行条目分析与评价。方法采用QLICD-CPHD(V2.0)量表对184名慢性肺源性心脏病患者进...目的应用经典测量理论(classical test theory,CTT)和项目反应理论(item response theory,IRT)对慢性肺源性心脏病生命质量测定量表[QLICD-CPHD(V2.0)]进行条目分析与评价。方法采用QLICD-CPHD(V2.0)量表对184名慢性肺源性心脏病患者进行调查,运用经典测量理论中的相关系数法、变异度法、因子分析法、克朗巴赫系数法对QLICD-CPHD(V2.0)量表的条目进行分析评定,同时运用项目反应理论中的Samejima等级反应模型计算量表每个条目的难度、信息量和区分度系数。结果CTT结果提示存在7个条目不满足至少3种的统计学要求,其中共性模块6个,特异模块1个。IRT结果显示条目区分度范围为1.18~1.44较为适宜。难度系数随难度等级(B1→B4)增加而单调递增,存在部分条目难度系数b超过标准值范围。各条目平均信息量分布在0.185~0.576。结论经CTT与IRT分析,QLICD-CPHD(V2.0)量表的大部分条目质量较高,具有较好的区分度,但仍有少量条目需进一步分析和修订。展开更多
文摘A systematic method is developed to studY the classical motion of a mass point in gravitational gauge field. First, by using Mathematica, a spherical symmetric solution of the field equation of gravitational gauge field is obtained, which is just the traditional Schwarzschild solution. Combining the principle of gauge covariance and Newton＇s second law of motion, the equation of motion of a mass point in gravitational field is deduced. Based on the spherical symmetric solution of the field equation and the equation of motion of a mass point in gravitational field, we can discuss classical tests of gauge theory of gravity, including the deflection of light by the sun, the precession of the perihelia of the orbits of the inner planets and the time delay of radar echoes passing the sun. It is found that the theoretical predictions of these classical tests given by gauge theory of gravity are completely the same as those given by general relativity.
基金supported by the National Natural Science Foundation of China(Grant No 10674066)the Open Project in State Key Laboratory of Acoustics(Grant No 200802)
文摘It is known that the strength of concrete is seriously affected by damage and cracking. In this paper, six concrete samples under different damage levels are studied. The experimental results show a linear dependence of the resonance frequency shift on strain amplitude at the fundamental frequency, and approximate quadratic dependence of the am- plitudes of the second and third harmonics on strain amplitude at the fundamental frequency as well. In addition, the amplitude of the third harmonics is shown to increase with the increase of damage level, which is even higher than that of the second harmonics in samples with higher damage levels. These are three properties of non-classical nonlinear acoustics. The nonlinear parameters increase from 106 to 108 with damage level, and are more sensitive to the damage level of the concrete than the linear parameters obtained by using traditional acoustics methods. So, this method based on non-classical nonlinear acoustics may provide a better means of non-destructive testing （NDT） of concrete and other porous materials.
文摘目的:汉化冠心病患者运动恐惧量表(Fear of Activity in Patients with Coronary Artery Disease,Fact-CAD),为国内冠心病患者运动恐惧的评估提供科学、可靠的特异性工具。方法:遵循Brislin翻译模型对量表进行翻译、回译和文化调适,形成中文版Fact-CAD量表。于2022年10月至2023年2月,采用便利抽样法,选取杭州市某三级甲等医院的334例冠心病患者进行调查,结合Rasch模型分析和经典测量理论对问卷的信度、效度进行评价。结果:中文版Fact-CAD为单维度,包括19个条目。各条目的未加权均方拟合统计量值为0.72~2.10,加权均方拟合统计量为0.88~1.29,条目-总分的相关系数为0.04~0.58,各条目拟合结果符合Rasch模型。以中文版多维度运动自我效能量表作为聚合效度指标,相关系数为-0.636(P<0.01),量表平均内容效度指数为0.951。总量表的Cronbach’sα系数为0.901,Guttman折半信度为0.885,重测信度为0.893。结论:中文版Fact-CAD具有良好的信度、效度,量表条目少,评估时间短,难度适中,适用于我国冠心病患者运动恐惧的评估。
文摘目的应用经典测量理论(classical test theory,CTT)和项目反应理论(item response theory,IRT)对慢性肺源性心脏病生命质量测定量表[QLICD-CPHD(V2.0)]进行条目分析与评价。方法采用QLICD-CPHD(V2.0)量表对184名慢性肺源性心脏病患者进行调查,运用经典测量理论中的相关系数法、变异度法、因子分析法、克朗巴赫系数法对QLICD-CPHD(V2.0)量表的条目进行分析评定,同时运用项目反应理论中的Samejima等级反应模型计算量表每个条目的难度、信息量和区分度系数。结果CTT结果提示存在7个条目不满足至少3种的统计学要求,其中共性模块6个,特异模块1个。IRT结果显示条目区分度范围为1.18~1.44较为适宜。难度系数随难度等级(B1→B4)增加而单调递增,存在部分条目难度系数b超过标准值范围。各条目平均信息量分布在0.185~0.576。结论经CTT与IRT分析,QLICD-CPHD(V2.0)量表的大部分条目质量较高,具有较好的区分度,但仍有少量条目需进一步分析和修订。
