Japanese larch is one of the main plantation tree species in China.A lack of engineered wood products made by Japanese larch,however,limits its application in wood stnuctures.In this study,based on optimum process par...Japanese larch is one of the main plantation tree species in China.A lack of engineered wood products made by Japanese larch,however,limits its application in wood stnuctures.In this study,based on optimum process parameters,such as pressure(12 MPa),adhesive spread rate(200 g/m^(2))and adhesive(one-component polyurethane),the mechanical properties of Japanese larch-made cross-laminated timber(CLT)with different lay-ups were evaluated by means of the static method.Results of this study showed that variations in lay-ups significantly affected the mechanical properties of CLT.The strength and modulus of bending and parallel compression for CLT increased with the thickness of lumber,while that of bending,parallel compression and rolling shear all decreased with the number of layers.Thickness,layup orientation and the number of layers all had an impact on the strength of CLT.Failure modes obtained from numerical simulation were basically the same as those of experimental tests.There was also strong alignment between theoretical value and test value for effective bending stifness and shear stifness.Thus,the shear analogy method can be used to predict the mechanical properties of CLT effectively.This study proved great potential in using Japanese larch wood for manufacturing CLT due to its good mechanical properties.展开更多
Objective: To explore the analgesic effects and uterine hemodynamics of perpendicular needling(PN)and transverse needling(TN) at SP 6 in patients with primary dysmenorrhea(PD).Methods: In this randomized controlled tr...Objective: To explore the analgesic effects and uterine hemodynamics of perpendicular needling(PN)and transverse needling(TN) at SP 6 in patients with primary dysmenorrhea(PD).Methods: In this randomized controlled trial, patients with PD diagnosed with cold-dampness congealing pattern were randomly assigned in a ratio of 1:1 to receive PN or TN at bilateral SP 6 for 10 min.Acupuncture was performed when the menstrual pain score was over 40 mm on the first day of menstruation, as measured using the visual analog scale for pain(VAS-P). The primary outcome was average menstrual pain(VAS-P). Secondary outcomes included the pulsatility index(PI), resistance index(RI), and systolic-diastolic peaks ratio(S/D) in uterine arteries as measured using color Doppler ultrasonography;anxiety as assessed using the Hamilton Anxiety Rating Scale(HAMA), blood pressure(BP),and heart rate(HR).Results: Forty-eight patients completed the study. The TN group exhibited a significant reduction in VAS-P scores(-5.71 mm, 95% confidence interval(CI): -8.78, -2.63, P =.001), RI values(-0.05, 95% CI:-0.09, -0.01, P=.015), and HAMA values(-2.50, 95% CI: -4.78, -0.22, P=.032) when compared with the PN group. No significant differences in PI, S/D, BP, or HR values were observed between the two groups(P >.05).Conclusion: TN at SP 6 was superior to PN in alleviating menstrual pain and anxiety in patients with PD.This analgesic effect of TN may be due to its better ability to improve uterine arterial blood flow via decreases in RI values.展开更多
在基于LoRa(Long Range Radio)的大规模物联网系统中,为了在低功耗的前提下降低通信延迟,同时与LoRa系统的通信距离相近,提出一种基于低功耗下变频和模拟解扩频机制的LoRa唤醒接收机制。首先利用发射机发出一个标准的LoRa前导码序列和...在基于LoRa(Long Range Radio)的大规模物联网系统中,为了在低功耗的前提下降低通信延迟,同时与LoRa系统的通信距离相近,提出一种基于低功耗下变频和模拟解扩频机制的LoRa唤醒接收机制。首先利用发射机发出一个标准的LoRa前导码序列和一个与其中心频率有一定频率差的单音载波。其次在接收端天线对前导码序列和载波同时接收后,利用肖特基二极管的非线性效应,使两个信号完成混频,即单音载波充当本振信号并实现LoRa信号的下变频。然后控制射频开关的通断时序完成对接收信号的解扩频。最后对解调信号进行基带处理,利用两路正交信号降低误码率。理论分析和仿真结果表明,本文提出的基于模拟扩频信号处理的超低功耗唤醒机制在LoRa系统中具有可行性,接收灵敏度最高达到-136 dBm且整体功耗仅为137μW。展开更多
基金by basic operating budget of scientific research institutes for public welfare at the central level(CAFBB2018SY032)China Postdoctoral Science Foundation (No.2018M641225).
文摘Japanese larch is one of the main plantation tree species in China.A lack of engineered wood products made by Japanese larch,however,limits its application in wood stnuctures.In this study,based on optimum process parameters,such as pressure(12 MPa),adhesive spread rate(200 g/m^(2))and adhesive(one-component polyurethane),the mechanical properties of Japanese larch-made cross-laminated timber(CLT)with different lay-ups were evaluated by means of the static method.Results of this study showed that variations in lay-ups significantly affected the mechanical properties of CLT.The strength and modulus of bending and parallel compression for CLT increased with the thickness of lumber,while that of bending,parallel compression and rolling shear all decreased with the number of layers.Thickness,layup orientation and the number of layers all had an impact on the strength of CLT.Failure modes obtained from numerical simulation were basically the same as those of experimental tests.There was also strong alignment between theoretical value and test value for effective bending stifness and shear stifness.Thus,the shear analogy method can be used to predict the mechanical properties of CLT effectively.This study proved great potential in using Japanese larch wood for manufacturing CLT due to its good mechanical properties.
基金funded by the Longitudinal Research Project of BUCM (2018-ZXFZJJ-010)。
文摘Objective: To explore the analgesic effects and uterine hemodynamics of perpendicular needling(PN)and transverse needling(TN) at SP 6 in patients with primary dysmenorrhea(PD).Methods: In this randomized controlled trial, patients with PD diagnosed with cold-dampness congealing pattern were randomly assigned in a ratio of 1:1 to receive PN or TN at bilateral SP 6 for 10 min.Acupuncture was performed when the menstrual pain score was over 40 mm on the first day of menstruation, as measured using the visual analog scale for pain(VAS-P). The primary outcome was average menstrual pain(VAS-P). Secondary outcomes included the pulsatility index(PI), resistance index(RI), and systolic-diastolic peaks ratio(S/D) in uterine arteries as measured using color Doppler ultrasonography;anxiety as assessed using the Hamilton Anxiety Rating Scale(HAMA), blood pressure(BP),and heart rate(HR).Results: Forty-eight patients completed the study. The TN group exhibited a significant reduction in VAS-P scores(-5.71 mm, 95% confidence interval(CI): -8.78, -2.63, P =.001), RI values(-0.05, 95% CI:-0.09, -0.01, P=.015), and HAMA values(-2.50, 95% CI: -4.78, -0.22, P=.032) when compared with the PN group. No significant differences in PI, S/D, BP, or HR values were observed between the two groups(P >.05).Conclusion: TN at SP 6 was superior to PN in alleviating menstrual pain and anxiety in patients with PD.This analgesic effect of TN may be due to its better ability to improve uterine arterial blood flow via decreases in RI values.
文摘在基于LoRa(Long Range Radio)的大规模物联网系统中,为了在低功耗的前提下降低通信延迟,同时与LoRa系统的通信距离相近,提出一种基于低功耗下变频和模拟解扩频机制的LoRa唤醒接收机制。首先利用发射机发出一个标准的LoRa前导码序列和一个与其中心频率有一定频率差的单音载波。其次在接收端天线对前导码序列和载波同时接收后,利用肖特基二极管的非线性效应,使两个信号完成混频,即单音载波充当本振信号并实现LoRa信号的下变频。然后控制射频开关的通断时序完成对接收信号的解扩频。最后对解调信号进行基带处理,利用两路正交信号降低误码率。理论分析和仿真结果表明,本文提出的基于模拟扩频信号处理的超低功耗唤醒机制在LoRa系统中具有可行性,接收灵敏度最高达到-136 dBm且整体功耗仅为137μW。
