In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, th...In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, the volume of coal outbursts and the temperature during the outburst process were studied. The results show that： l） for coal seams with similar structure and com- ponents, two factors, i.e., gas pressure and ground stress affect the volume of coal outbursts, with gas pressure being the more im- portant of the two and 2） the changes in coal temperature, both its increase and decrease, are affected by ground stress and gas pressure, it is a process of change. Preliminary tests show that the system can simulate the dynamic interaction of coal and gas, which is helpful for studying the dynamic mechanism of solid-gas coupling of gas and coal.展开更多
A novel bandpass filter(BPF)based on spoof surface plasmon polaritons(SSPPs)using a compact folded slotline structure is proposed and experimentally demonstrated.The proposed novel SSPPs structure compared with a conv...A novel bandpass filter(BPF)based on spoof surface plasmon polaritons(SSPPs)using a compact folded slotline structure is proposed and experimentally demonstrated.The proposed novel SSPPs structure compared with a conventional plasmonic waveguide with slot line SSPPs unit structure at the same size,the considerable advantages in much lower asymptotic frequency with tight field confinement,which enable the proposed filter to be more miniaturization.A high-efficient mode conversion structure is designed to transition from TE-mode to SSPPs-mode by gradient slotline lengths.The low-frequency stop-band can be committed with microstrip to slotline evolution on both sides of the dielectric,while the high-frequency cutoff band is realized by the proposed SSPPs structure.The influence of dispersion relation,electric field distribution,surface current,and structural parameters on the transmission characteristics of the proposed BPF are analyzed by finite difference time domain(FDTD).To validate the design concept,the prototype of the miniaturized SSPPs BPF has been manufactured and measured.The experimental results show high performance of the fabricated sample,in which the working in a range of 0.9 GHz-5.2 GHz with the relative bandwidth is 142%,the insertion loss less than 0.5 dB,the reflection coefficient less than-10 dB,and the group delay is less than one ns.This works provides a mirror for realizing the miniaturization of waveguides,and the application and development of high-confinement SSPPs functional devices in the microwave and THz regimes.展开更多
目的比较横向松质骨拉力螺钉(transverse cancellous lag screw,TCLS)和普通空心螺钉(ordinary cannulated screw,OCS)对股骨颈骨折的治疗效果。方法回顾性分析2016年1月至2018年12月,我院收治的85例PauwelsⅢ型股骨颈骨折患者,其中男46...目的比较横向松质骨拉力螺钉(transverse cancellous lag screw,TCLS)和普通空心螺钉(ordinary cannulated screw,OCS)对股骨颈骨折的治疗效果。方法回顾性分析2016年1月至2018年12月,我院收治的85例PauwelsⅢ型股骨颈骨折患者,其中男46例,女39例;年龄19~62岁,平均55.2岁。分为TCLS固定组(TCLS组,n=42)和OCS固定组(OCS组,n=43)。收集围术期临床指标(包括手术时间、术中失血量、临床抽血化验指标和住院时间);术后各种量表进行评估,包括疼痛视觉模拟评分(visual analogue scale,VAS)和Harris髋关节评分(Harris hip score,HHS),记录并发症(骨不连、股骨头坏死、股骨颈短缩和固定失败),并进行统计学比较。结果TCLS组的平均随访时间为15.4个月,OCS组的平均随访时间为14.7个月。两组之间手术时间、术中失血量以及治疗前后的血红蛋白和住院时间差异均无统计学意义(P>0.05)。两组VAS评分以及包括骨不连和股骨头坏死在内的并发症发生率差异也无统计学意义。但是在末次随访中,TCLS组的HHS评分优于OCS组,并且与OCS组相比,TCLS组的股骨颈短缩率显著降低,差异有统计学意义(P<0.05)。结论TCLS技术治疗股骨颈骨折可显著改善髋关节功能,并降低术后股骨颈短缩率,并为股骨颈骨折的治疗提供了新颖的见解。展开更多
文摘In order to study the dynamic action and physical effects of coal seams and gas, a simulation system for this dynamic action was developed and a physical model built in our laboratory. Using this newly built model, the volume of coal outbursts and the temperature during the outburst process were studied. The results show that： l） for coal seams with similar structure and com- ponents, two factors, i.e., gas pressure and ground stress affect the volume of coal outbursts, with gas pressure being the more im- portant of the two and 2） the changes in coal temperature, both its increase and decrease, are affected by ground stress and gas pressure, it is a process of change. Preliminary tests show that the system can simulate the dynamic interaction of coal and gas, which is helpful for studying the dynamic mechanism of solid-gas coupling of gas and coal.
基金the National Natural Science Foundation of China(Grant Nos.62071221 and 62071442)the Equipment Advance Research Foundation of China(Grant No.80909010302)the Key Laboratory of Radar Imaging and Microwave Photonics(Nanjing University of Aeronautics and Astronautics),Ministry of Education of China(Grant No.NJ20210006).
文摘A novel bandpass filter(BPF)based on spoof surface plasmon polaritons(SSPPs)using a compact folded slotline structure is proposed and experimentally demonstrated.The proposed novel SSPPs structure compared with a conventional plasmonic waveguide with slot line SSPPs unit structure at the same size,the considerable advantages in much lower asymptotic frequency with tight field confinement,which enable the proposed filter to be more miniaturization.A high-efficient mode conversion structure is designed to transition from TE-mode to SSPPs-mode by gradient slotline lengths.The low-frequency stop-band can be committed with microstrip to slotline evolution on both sides of the dielectric,while the high-frequency cutoff band is realized by the proposed SSPPs structure.The influence of dispersion relation,electric field distribution,surface current,and structural parameters on the transmission characteristics of the proposed BPF are analyzed by finite difference time domain(FDTD).To validate the design concept,the prototype of the miniaturized SSPPs BPF has been manufactured and measured.The experimental results show high performance of the fabricated sample,in which the working in a range of 0.9 GHz-5.2 GHz with the relative bandwidth is 142%,the insertion loss less than 0.5 dB,the reflection coefficient less than-10 dB,and the group delay is less than one ns.This works provides a mirror for realizing the miniaturization of waveguides,and the application and development of high-confinement SSPPs functional devices in the microwave and THz regimes.
文摘目的比较横向松质骨拉力螺钉(transverse cancellous lag screw,TCLS)和普通空心螺钉(ordinary cannulated screw,OCS)对股骨颈骨折的治疗效果。方法回顾性分析2016年1月至2018年12月,我院收治的85例PauwelsⅢ型股骨颈骨折患者,其中男46例,女39例;年龄19~62岁,平均55.2岁。分为TCLS固定组(TCLS组,n=42)和OCS固定组(OCS组,n=43)。收集围术期临床指标(包括手术时间、术中失血量、临床抽血化验指标和住院时间);术后各种量表进行评估,包括疼痛视觉模拟评分(visual analogue scale,VAS)和Harris髋关节评分(Harris hip score,HHS),记录并发症(骨不连、股骨头坏死、股骨颈短缩和固定失败),并进行统计学比较。结果TCLS组的平均随访时间为15.4个月,OCS组的平均随访时间为14.7个月。两组之间手术时间、术中失血量以及治疗前后的血红蛋白和住院时间差异均无统计学意义(P>0.05)。两组VAS评分以及包括骨不连和股骨头坏死在内的并发症发生率差异也无统计学意义。但是在末次随访中,TCLS组的HHS评分优于OCS组,并且与OCS组相比,TCLS组的股骨颈短缩率显著降低,差异有统计学意义(P<0.05)。结论TCLS技术治疗股骨颈骨折可显著改善髋关节功能,并降低术后股骨颈短缩率,并为股骨颈骨折的治疗提供了新颖的见解。
