Combining with the technology of self-compacting concrete, self-stressing concrete and concrete-filled steel tube, we can get self-compacting and self-stressing concrete-filled steel tube. In order to study the expans...Combining with the technology of self-compacting concrete, self-stressing concrete and concrete-filled steel tube, we can get self-compacting and self-stressing concrete-filled steel tube. In order to study the expansive mechanism of self-stressing concrete, the continuous observation of 47 days on six specimens was carried on. The specimens have different steel area to concrete area ratio. The expansive process in hoop and axial direction were studied, and the expansive mechanism was discussed too. The experimental results identify that the creep and elastic deformation take a large proportion in effective free expansion. The calculating formulas of self-stress in hoop and axial directions were presented here.展开更多
The expansive behaviors of the expensive concrete under different restraining conditions were systemically studied. The experimental results indicate that expansive deformation obviously increases before 10 days and t...The expansive behaviors of the expensive concrete under different restraining conditions were systemically studied. The experimental results indicate that expansive deformation obviously increases before 10 days and tends to be constant after 25 days regardless of the restraining conditions. The mixture ratio of expansive cement and restraining conditions are the main factors affecting expansive deformation. Self-stress can be obtained when the expansive deformation is restrained. The higher self-stress could be obtained when the expensive concrete is restrained by steel tube. For specimens under steel tube restraining, the wall thickness and the length of the steel tube have important influence on self-stress. Both the radial self-stress and axial self-stress in concrete core increase when wall thickness or length of the steel tube increases.展开更多
Through the experiments of 7 T-section composite beams, steel fiber reinforced self-stressing concrete （SFRSC） as the composite beam in the composite layer was studied under the hogging bending. The tests simulated ...Through the experiments of 7 T-section composite beams, steel fiber reinforced self-stressing concrete （SFRSC） as the composite beam in the composite layer was studied under the hogging bending. The tests simulated composite layer tensile strain under the hogging bending of inverted loading composite beams, giving the relationship under the different fatigue stress ratios between fatigue cycles and steel bar’s stress range, crack width, stiffness loss and damage, etc., in composite layer. This article established fatigue life equation, and analyzed SFRSC reinforced mechanism to crack width and stiffness loss. The results show that SFRSC as the composite beam concrete has excellent properties of crack resistance and tensile, can reinforce the fatigue crack width and stiffness loss of composite beams, and improve the durability and in normal use of composite beams in the hogging bending zone.展开更多
A total of fifteen self-stressing and selfcompacting concrete(SSC)filled steel tube columns and three common self-compacting concrete filled steel tube(CFST)columns are tested under eccentric compression load to analy...A total of fifteen self-stressing and selfcompacting concrete(SSC)filled steel tube columns and three common self-compacting concrete filled steel tube(CFST)columns are tested under eccentric compression load to analyze the the effect of initial self-stress on the compression behavior of CFSTs.The results show that the elastic working range of the columns is lengthened because of initial self-stress and it slightly decreases with the increase of load eccentricity ratio and slenderness ratio.Because of the initial self-stress,the concrete core is always under compression in three directions,so the compactness is enhanced and the ultimate bearing capacity obviously increases;but the initial self-stress hardly affects the failure mode of the columns.展开更多
目的评价卒中后失语患者心理一致感,分析影响卒中后失语患者心理一致感的因素。方法本研究为前瞻性观察性研究。连续招募2018年12月—2022年12月首都医科大学附属北京天坛医院收治的144例卒中后失语患者,采用一般资料调查问卷收集患者...目的评价卒中后失语患者心理一致感,分析影响卒中后失语患者心理一致感的因素。方法本研究为前瞻性观察性研究。连续招募2018年12月—2022年12月首都医科大学附属北京天坛医院收治的144例卒中后失语患者,采用一般资料调查问卷收集患者的临床资料,采用中国康复研究中心汉语标准失语症检查法(China rehabilitation research center aphasia examination,CRRCAE)评估失语程度,采用中文版心理一致感量表(sense of coherence-13 scale,SOC-13)、社会支持量表(social support scale,SSRS)、一般自我效能感量表(general self-efficacy scale,GSES)、中文版知觉压力量表(Chinese-version perceived stress scale,CPSS)评估患者的心理一致感、社会支持、自我效能和知觉压力。分析中文版SOC-13总分与SSRS、GSES、CPSS总分的相关性。使用多重线性回归分析影响卒中后失语患者心理一致感水平的因素。结果卒中后失语患者中文版SOC-13总分为(57.96±12.11)分,心理一致感处于低水平。卒中后失语患者中文版SOC-13总分与SSRS总分(r=0.592,P<0.05)、GSES总分(r=0.470,P<0.05)呈正相关,与CPSS总分呈负相关(r=-0.410,P<0.05)。多重线性回归分析显示,抑郁(β=1.006,P=0.001)、日常生活能力(β=1.124,P=0.003)、CRRCAE评分(β=1.325,P<0.001)、SSRS总分(β=1.123,P=0.009)、GSES总分(β=0.341,P=0.015)、CPSS总分(β=-0.402,P=0.023)是卒中后失语患者低中文版SOC-13总分的影响因素。结论卒中后失语患者心理一致感水平偏低。抑郁、日常生活能力、失语程度、社会支持、自我效能、知觉压力是患者心理一致感水平的影响因素。展开更多
目的探究最好自我(best possible self,BPS)训练对集训期新兵心理健康状况(乐观与悲观情绪、知觉压力和主观幸福感)的干预效果。方法采用非随机对照试验设计方案,以整群抽样法于2023年9月在某新兵训练基地抽取212名新兵,根据建制分为研...目的探究最好自我(best possible self,BPS)训练对集训期新兵心理健康状况(乐观与悲观情绪、知觉压力和主观幸福感)的干预效果。方法采用非随机对照试验设计方案,以整群抽样法于2023年9月在某新兵训练基地抽取212名新兵,根据建制分为研究组(100人,行BPS训练15 min/d)和对照组[112人,行日常生活(typical day,TD)表象训练,15 min/d],连续干预2周。于干预当天(T0),干预实施1周(T1)、2周(T2),干预结束后1周(T3)采用未来预期量表(Future Expectation Scale,FEX)、知觉压力量表(Chinese Perceived Stress Scale,CPSS)、正负性情绪量表(Positive and Negative Affect Scale,PANAS)和生活满意度量表(Satisfaction with Life Scale,SWLS)对2组被试进行测量,评估BPS训练对上述心理健康指标的训练效果。结果2组被试的人口统计学信息及各心理学基线指标均衡。随着训练的进行,2组在悲观情绪、知觉压力和主观幸福感(包含情感和认知幸福感)上的训练效果表现出明显的差异(P<0.05)。研究组T1~T3的悲观情绪相比基线(T0)明显降低(P<0.01),情感幸福感(P<0.01)和认知幸福感(P<0.01)明显升高,其知觉压力在T1(P<0.05)和T3(P<0.01)也明显降低;而对照组在训练前后却无上述明显变化。结论2周BPS训练可有效降低集训期新兵悲观情绪和知觉压力水平,提升其主观幸福感,促进新兵心理健康。展开更多
为了研究应力对自润滑关节轴承摩擦磨损性能的影响,依据SAE AS 81820对EN2584R12轴承在常温下分别进行了50%、100%和150%标准应力条件下的全寿命摆动磨损测试,并对粘贴衬垫的平板样件进行静应力承载测试。采用三维白光干涉形貌仪与金相...为了研究应力对自润滑关节轴承摩擦磨损性能的影响,依据SAE AS 81820对EN2584R12轴承在常温下分别进行了50%、100%和150%标准应力条件下的全寿命摆动磨损测试,并对粘贴衬垫的平板样件进行静应力承载测试。采用三维白光干涉形貌仪与金相显微镜(OM)观察静应力承载后衬垫的变形情况,采用体视显微镜(SM)、光学显微镜(OM)和扫描电子显微镜(SEM)观察不同应力下轴承全寿命摆动磨损后内外圈磨损形貌与磨屑形貌。结果表明:全寿命周期内,三种应力下的自润滑衬垫均已磨穿,磨损规律和摩擦因数差异不大,应力越大,轴承表面温度越高,磨屑颜色越深、尺寸越大,失稳期来得更早,破坏更为剧烈;应力对轴承的寿命有显著影响,低应力和中应力条件下的摆动磨损寿命分别是高应力条件的17.95倍和7.86倍;三种应力下的磨损机理均为磨粒磨损与黏着磨损的混合磨损,直接受力区的黏着磨损随载荷的增大而加剧,非直接受力区的磨粒磨损随载荷的增大而减弱。展开更多
基金the National Natural Science Foundation of China (50578027)
文摘Combining with the technology of self-compacting concrete, self-stressing concrete and concrete-filled steel tube, we can get self-compacting and self-stressing concrete-filled steel tube. In order to study the expansive mechanism of self-stressing concrete, the continuous observation of 47 days on six specimens was carried on. The specimens have different steel area to concrete area ratio. The expansive process in hoop and axial direction were studied, and the expansive mechanism was discussed too. The experimental results identify that the creep and elastic deformation take a large proportion in effective free expansion. The calculating formulas of self-stress in hoop and axial directions were presented here.
基金Funded by the NSFC (No.50578027)the Key Subject Foundation of Henan Province (No.504906)the Doctor Foundation of Henan Polytechnic University (No.B2009-2)
文摘The expansive behaviors of the expensive concrete under different restraining conditions were systemically studied. The experimental results indicate that expansive deformation obviously increases before 10 days and tends to be constant after 25 days regardless of the restraining conditions. The mixture ratio of expansive cement and restraining conditions are the main factors affecting expansive deformation. Self-stress can be obtained when the expansive deformation is restrained. The higher self-stress could be obtained when the expensive concrete is restrained by steel tube. For specimens under steel tube restraining, the wall thickness and the length of the steel tube have important influence on self-stress. Both the radial self-stress and axial self-stress in concrete core increase when wall thickness or length of the steel tube increases.
基金Project supported by the Science and Technology of Department of Communications of Liaoning Province (Grant No.200514)the Science and Technology of Department of Education of Liaoning Province (Grant No.L2010378)
文摘Through the experiments of 7 T-section composite beams, steel fiber reinforced self-stressing concrete （SFRSC） as the composite beam in the composite layer was studied under the hogging bending. The tests simulated composite layer tensile strain under the hogging bending of inverted loading composite beams, giving the relationship under the different fatigue stress ratios between fatigue cycles and steel bar’s stress range, crack width, stiffness loss and damage, etc., in composite layer. This article established fatigue life equation, and analyzed SFRSC reinforced mechanism to crack width and stiffness loss. The results show that SFRSC as the composite beam concrete has excellent properties of crack resistance and tensile, can reinforce the fatigue crack width and stiffness loss of composite beams, and improve the durability and in normal use of composite beams in the hogging bending zone.
文摘A total of fifteen self-stressing and selfcompacting concrete(SSC)filled steel tube columns and three common self-compacting concrete filled steel tube(CFST)columns are tested under eccentric compression load to analyze the the effect of initial self-stress on the compression behavior of CFSTs.The results show that the elastic working range of the columns is lengthened because of initial self-stress and it slightly decreases with the increase of load eccentricity ratio and slenderness ratio.Because of the initial self-stress,the concrete core is always under compression in three directions,so the compactness is enhanced and the ultimate bearing capacity obviously increases;but the initial self-stress hardly affects the failure mode of the columns.
文摘目的评价卒中后失语患者心理一致感,分析影响卒中后失语患者心理一致感的因素。方法本研究为前瞻性观察性研究。连续招募2018年12月—2022年12月首都医科大学附属北京天坛医院收治的144例卒中后失语患者,采用一般资料调查问卷收集患者的临床资料,采用中国康复研究中心汉语标准失语症检查法(China rehabilitation research center aphasia examination,CRRCAE)评估失语程度,采用中文版心理一致感量表(sense of coherence-13 scale,SOC-13)、社会支持量表(social support scale,SSRS)、一般自我效能感量表(general self-efficacy scale,GSES)、中文版知觉压力量表(Chinese-version perceived stress scale,CPSS)评估患者的心理一致感、社会支持、自我效能和知觉压力。分析中文版SOC-13总分与SSRS、GSES、CPSS总分的相关性。使用多重线性回归分析影响卒中后失语患者心理一致感水平的因素。结果卒中后失语患者中文版SOC-13总分为(57.96±12.11)分,心理一致感处于低水平。卒中后失语患者中文版SOC-13总分与SSRS总分(r=0.592,P<0.05)、GSES总分(r=0.470,P<0.05)呈正相关,与CPSS总分呈负相关(r=-0.410,P<0.05)。多重线性回归分析显示,抑郁(β=1.006,P=0.001)、日常生活能力(β=1.124,P=0.003)、CRRCAE评分(β=1.325,P<0.001)、SSRS总分(β=1.123,P=0.009)、GSES总分(β=0.341,P=0.015)、CPSS总分(β=-0.402,P=0.023)是卒中后失语患者低中文版SOC-13总分的影响因素。结论卒中后失语患者心理一致感水平偏低。抑郁、日常生活能力、失语程度、社会支持、自我效能、知觉压力是患者心理一致感水平的影响因素。
文摘目的探究最好自我(best possible self,BPS)训练对集训期新兵心理健康状况(乐观与悲观情绪、知觉压力和主观幸福感)的干预效果。方法采用非随机对照试验设计方案,以整群抽样法于2023年9月在某新兵训练基地抽取212名新兵,根据建制分为研究组(100人,行BPS训练15 min/d)和对照组[112人,行日常生活(typical day,TD)表象训练,15 min/d],连续干预2周。于干预当天(T0),干预实施1周(T1)、2周(T2),干预结束后1周(T3)采用未来预期量表(Future Expectation Scale,FEX)、知觉压力量表(Chinese Perceived Stress Scale,CPSS)、正负性情绪量表(Positive and Negative Affect Scale,PANAS)和生活满意度量表(Satisfaction with Life Scale,SWLS)对2组被试进行测量,评估BPS训练对上述心理健康指标的训练效果。结果2组被试的人口统计学信息及各心理学基线指标均衡。随着训练的进行,2组在悲观情绪、知觉压力和主观幸福感(包含情感和认知幸福感)上的训练效果表现出明显的差异(P<0.05)。研究组T1~T3的悲观情绪相比基线(T0)明显降低(P<0.01),情感幸福感(P<0.01)和认知幸福感(P<0.01)明显升高,其知觉压力在T1(P<0.05)和T3(P<0.01)也明显降低;而对照组在训练前后却无上述明显变化。结论2周BPS训练可有效降低集训期新兵悲观情绪和知觉压力水平,提升其主观幸福感,促进新兵心理健康。
文摘为了研究应力对自润滑关节轴承摩擦磨损性能的影响,依据SAE AS 81820对EN2584R12轴承在常温下分别进行了50%、100%和150%标准应力条件下的全寿命摆动磨损测试,并对粘贴衬垫的平板样件进行静应力承载测试。采用三维白光干涉形貌仪与金相显微镜(OM)观察静应力承载后衬垫的变形情况,采用体视显微镜(SM)、光学显微镜(OM)和扫描电子显微镜(SEM)观察不同应力下轴承全寿命摆动磨损后内外圈磨损形貌与磨屑形貌。结果表明:全寿命周期内,三种应力下的自润滑衬垫均已磨穿,磨损规律和摩擦因数差异不大,应力越大,轴承表面温度越高,磨屑颜色越深、尺寸越大,失稳期来得更早,破坏更为剧烈;应力对轴承的寿命有显著影响,低应力和中应力条件下的摆动磨损寿命分别是高应力条件的17.95倍和7.86倍;三种应力下的磨损机理均为磨粒磨损与黏着磨损的混合磨损,直接受力区的黏着磨损随载荷的增大而加剧,非直接受力区的磨粒磨损随载荷的增大而减弱。
