All-cellulose composites(ACCs)are composites that use non-derivatized cellulose as both the matrix and the reinforcement phase.ACC consists entirely of cellulose,and since the reinforcement phase and the matrix have e...All-cellulose composites(ACCs)are composites that use non-derivatized cellulose as both the matrix and the reinforcement phase.ACC consists entirely of cellulose,and since the reinforcement phase and the matrix have exactly the same chemical properties,they can overcome the problem of poor fiber-matrix adhesion in biocomposites.In this study,ACC was prepared by partially dissolving wood pulp in a cryogenic aqueous phosphoric acid solution,and the effects of dissolution temperature,dissolution time and pressing load on the properties of ACC were investigated.The results showed that a dissolution time of 45 min achieved the optimal reinforcement-matrix ratio.The use of an aqueous ethanol solution at an ethanol mass fraction of 50%as a coagulation bath and a pressing load of 3000 kg during the drying process achieved the best mechanical properties of ACC,with a tensile strength of 49.3 MPa(approximately 210%higher than that of the untreated wood pulp)and an elastic modulus of 1.6 GPa(approximately 122%higher than that of the untreated wood pulp).The composite’s compactness affected ACC’s mechanical properties.The air permeability analysis showed that the barrier performance of ACC was also significantly better than that of the untreated wood pulp.With a pressing load of 3500 kg,the surface water contact angle(WCA)increased to 110.3°(approximately 94%higher than that of the untreated wood pulp),and the air permeability was significantly reduced to 1.1 mm/s,showing its good application prospects in the field of green packaging materials.展开更多
提出一种基于小波互相关技术的微地震信号自动检测方法,利用复Morlet小波在特定尺度上对地震波形进行变换,分析其相位角相关性,设置合理的相似度阈值自动检测微小地震。对2018-05-01新疆昌吉M L 4.8地震后30 min的波形进行检测测试,共发...提出一种基于小波互相关技术的微地震信号自动检测方法,利用复Morlet小波在特定尺度上对地震波形进行变换,分析其相位角相关性,设置合理的相似度阈值自动检测微小地震。对2018-05-01新疆昌吉M L 4.8地震后30 min的波形进行检测测试,共发现11个微地震事件,并给出其检测台站的P波到时结果。与中国地震台网中心地震统一编目结果对比发现,无漏检、错检,P波到时结果相差基本在1 s之内,认为将该方法用于地震序列微地震检测具有一定的可行性。展开更多
本文基于匹配滤波技术,通过SEPD(Seismic Events and Phase Detection)对2018年11月25日新疆博乐MS4.9地震序列进行检测,检测出遗漏地震32条,84.4%地震为ML0.0-1.0,9.4%地震小于ML0.0,较地震目录中原有15条地震多213%,检测出的遗漏地震...本文基于匹配滤波技术,通过SEPD(Seismic Events and Phase Detection)对2018年11月25日新疆博乐MS4.9地震序列进行检测,检测出遗漏地震32条,84.4%地震为ML0.0-1.0,9.4%地震小于ML0.0,较地震目录中原有15条地震多213%,检测出的遗漏地震事件使地震目录更加完整。检测后的最小完整性震级由检测前的ML1.6减至ML0.8,地震目录最小完整性震级的减小有利于地震工作者对区域地震活动性作出更准确全面的结论,并使地震危险性分析更可靠。展开更多
基金Fundamental Research Funds for the Central Universities,China(No.2232023G-04)。
文摘All-cellulose composites(ACCs)are composites that use non-derivatized cellulose as both the matrix and the reinforcement phase.ACC consists entirely of cellulose,and since the reinforcement phase and the matrix have exactly the same chemical properties,they can overcome the problem of poor fiber-matrix adhesion in biocomposites.In this study,ACC was prepared by partially dissolving wood pulp in a cryogenic aqueous phosphoric acid solution,and the effects of dissolution temperature,dissolution time and pressing load on the properties of ACC were investigated.The results showed that a dissolution time of 45 min achieved the optimal reinforcement-matrix ratio.The use of an aqueous ethanol solution at an ethanol mass fraction of 50%as a coagulation bath and a pressing load of 3000 kg during the drying process achieved the best mechanical properties of ACC,with a tensile strength of 49.3 MPa(approximately 210%higher than that of the untreated wood pulp)and an elastic modulus of 1.6 GPa(approximately 122%higher than that of the untreated wood pulp).The composite’s compactness affected ACC’s mechanical properties.The air permeability analysis showed that the barrier performance of ACC was also significantly better than that of the untreated wood pulp.With a pressing load of 3500 kg,the surface water contact angle(WCA)increased to 110.3°(approximately 94%higher than that of the untreated wood pulp),and the air permeability was significantly reduced to 1.1 mm/s,showing its good application prospects in the field of green packaging materials.
文摘提出一种基于小波互相关技术的微地震信号自动检测方法,利用复Morlet小波在特定尺度上对地震波形进行变换,分析其相位角相关性,设置合理的相似度阈值自动检测微小地震。对2018-05-01新疆昌吉M L 4.8地震后30 min的波形进行检测测试,共发现11个微地震事件,并给出其检测台站的P波到时结果。与中国地震台网中心地震统一编目结果对比发现,无漏检、错检,P波到时结果相差基本在1 s之内,认为将该方法用于地震序列微地震检测具有一定的可行性。
文摘本文基于匹配滤波技术,通过SEPD(Seismic Events and Phase Detection)对2018年11月25日新疆博乐MS4.9地震序列进行检测,检测出遗漏地震32条,84.4%地震为ML0.0-1.0,9.4%地震小于ML0.0,较地震目录中原有15条地震多213%,检测出的遗漏地震事件使地震目录更加完整。检测后的最小完整性震级由检测前的ML1.6减至ML0.8,地震目录最小完整性震级的减小有利于地震工作者对区域地震活动性作出更准确全面的结论,并使地震危险性分析更可靠。
