This article investigates the separated flow around the bent-nose biconic, in which the second ordered TVD(Total Variation Diminishing) method is applied. The governing cqua-tion is a thin layer Navier-Stokes equation...This article investigates the separated flow around the bent-nose biconic, in which the second ordered TVD(Total Variation Diminishing) method is applied. The governing cqua-tion is a thin layer Navier-Stokes equation. The surface pressure distribution at the leeward side is a little higher in the vicinity of the symmetrical plane. This seems to be caused by the development of the vortex at the leeward side due to the separated flow. The location of a separation line and the size are in very good agreement with the experiment. Also the secondary separation is captured very clearly.展开更多
A biconical liner was optimized to improve its penetration ability. Its formation and pene- tration mechanism was studied through numerical simulation and experiments. And the influence of different liner geometry siz...A biconical liner was optimized to improve its penetration ability. Its formation and pene- tration mechanism was studied through numerical simulation and experiments. And the influence of different liner geometry sizes on the jet performance was analyzed using the orthogonal method. The liner formed the high-speed jet with an explosively formed projectile. The small angle 2a remarkably influenced the jet speed which was inversely proportional to 2a. And the liner thickness t＇ and large angle 2β had highly significant effect on the projectile speed. The liner was optimized at t＇ = 0. 14 cm, 2α = 50°, 2β = 135°, N = 0. 4 or 0. 5, when its jet speed respectively is at 6 613 m/s and 6 839 m/s and projectile speed is at 2 247 m/s and 2 095 m/s, steel target penetration is at 8. 24 cm and 8. 31 cm, and aperture is in 2.12 cm and 2.08 cm. The results show that target is penetrated by the high-speed jet and high-speed projectile resulting into double damages. The penetration ability is improved greatly.展开更多
In this paper, a novel surface-enhanced Raman scattering （SERS） sensor combined with fused biconical taper fiber （FBTF） and film coated with silver sols is proposed. This structure is designed to significantly inc...In this paper, a novel surface-enhanced Raman scattering （SERS） sensor combined with fused biconical taper fiber （FBTF） and film coated with silver sols is proposed. This structure is designed to significantly increase the SERS active surface when the length of the taper is increased and the radius is reduced, since the penetration depth is inversely proportional to the taper radius and proportional to the taper length according to the fiber-optic evanescent-wave theory. Based on the SERS sensing principle, the feasibility of FBTF sensor is analyzed in this paper. As a result, the Raman spectrum of R6G is obtained from the fused biconical taper zone surface coating with the silver sols in our experiments. The detected concentration is up to 10-7mol/L.展开更多
A wavelength modulation based fiber optic sensor is used to measure salt concentration and temperature. The sensor consists of a biconical fiber filter. Theoretically, the wavelength shift response of the sensor is li...A wavelength modulation based fiber optic sensor is used to measure salt concentration and temperature. The sensor consists of a biconical fiber filter. Theoretically, the wavelength shift response of the sensor is linearly related to changes in the refractive index of the external medium surrounding the sensor in a specific region. The device sensitivity is enhanced by reducing the radius of the taper waist. The theoretical predictions are confirmed by experimental results. A wavelength modulation based all fiber sensor demonstrated salt concentration and temperature measurements with errors of 0 05% (mass fraction) and 0 2℃, respectively. The differential modulation of the pass or notch bands in a biconical fiber filter may be used for simultaneous sensing of salt concentration and temperature.展开更多
目的:评估短种植体不同冠根比对种植体周骨改建的影响。方法:选取2011年1月~2013年6月后牙区种植患者27例,共69枚Bicon短种植体。经过5年功能负载后,通过影像学资料分析边缘骨吸收(marginal bone loss,MBL)、种植体周骨灰度值(grey-scal...目的:评估短种植体不同冠根比对种植体周骨改建的影响。方法:选取2011年1月~2013年6月后牙区种植患者27例,共69枚Bicon短种植体。经过5年功能负载后,通过影像学资料分析边缘骨吸收(marginal bone loss,MBL)、种植体周骨灰度值(grey-scale value,GSV)的改变与冠根比(crown-to-implant ratio,CIR)关系。结果:纳入研究的69枚Bicon种植体,经过(65±9)个月的功能负载,成功率为94.2%。按CIR进行分组,MBL、△GSV与CIR之间未发现显著相关(P>0.05);仅有2枚植体发生崩瓷,机械并发症比较差异无统计学意义(P>0.05)。结论:Bicon短种植体CIR对种植体周MBL、GSV改变没有明显影响,骨组织具有足够的改建活性以应对更大的应力刺激。高CIR未导致更多的机械并发症和种植体失败。展开更多
文摘This article investigates the separated flow around the bent-nose biconic, in which the second ordered TVD(Total Variation Diminishing) method is applied. The governing cqua-tion is a thin layer Navier-Stokes equation. The surface pressure distribution at the leeward side is a little higher in the vicinity of the symmetrical plane. This seems to be caused by the development of the vortex at the leeward side due to the separated flow. The location of a separation line and the size are in very good agreement with the experiment. Also the secondary separation is captured very clearly.
基金Supported by the National Natural Science Foundation of China(51174183)the Anhui Natural Science Foundation of China(1508085ME85)
文摘A biconical liner was optimized to improve its penetration ability. Its formation and pene- tration mechanism was studied through numerical simulation and experiments. And the influence of different liner geometry sizes on the jet performance was analyzed using the orthogonal method. The liner formed the high-speed jet with an explosively formed projectile. The small angle 2a remarkably influenced the jet speed which was inversely proportional to 2a. And the liner thickness t＇ and large angle 2β had highly significant effect on the projectile speed. The liner was optimized at t＇ = 0. 14 cm, 2α = 50°, 2β = 135°, N = 0. 4 or 0. 5, when its jet speed respectively is at 6 613 m/s and 6 839 m/s and projectile speed is at 2 247 m/s and 2 095 m/s, steel target penetration is at 8. 24 cm and 8. 31 cm, and aperture is in 2.12 cm and 2.08 cm. The results show that target is penetrated by the high-speed jet and high-speed projectile resulting into double damages. The penetration ability is improved greatly.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61027015, 60677031, 60937003)the Shanghai Leading Academic Discipline Project (Grant No.30108)the Science and Technology Commission of Shanghai Municipality (Grant No.10DZ2210900)
文摘In this paper, a novel surface-enhanced Raman scattering （SERS） sensor combined with fused biconical taper fiber （FBTF） and film coated with silver sols is proposed. This structure is designed to significantly increase the SERS active surface when the length of the taper is increased and the radius is reduced, since the penetration depth is inversely proportional to the taper radius and proportional to the taper length according to the fiber-optic evanescent-wave theory. Based on the SERS sensing principle, the feasibility of FBTF sensor is analyzed in this paper. As a result, the Raman spectrum of R6G is obtained from the fused biconical taper zone surface coating with the silver sols in our experiments. The detected concentration is up to 10-7mol/L.
文摘A wavelength modulation based fiber optic sensor is used to measure salt concentration and temperature. The sensor consists of a biconical fiber filter. Theoretically, the wavelength shift response of the sensor is linearly related to changes in the refractive index of the external medium surrounding the sensor in a specific region. The device sensitivity is enhanced by reducing the radius of the taper waist. The theoretical predictions are confirmed by experimental results. A wavelength modulation based all fiber sensor demonstrated salt concentration and temperature measurements with errors of 0 05% (mass fraction) and 0 2℃, respectively. The differential modulation of the pass or notch bands in a biconical fiber filter may be used for simultaneous sensing of salt concentration and temperature.
文摘目的:评估短种植体不同冠根比对种植体周骨改建的影响。方法:选取2011年1月~2013年6月后牙区种植患者27例,共69枚Bicon短种植体。经过5年功能负载后,通过影像学资料分析边缘骨吸收(marginal bone loss,MBL)、种植体周骨灰度值(grey-scale value,GSV)的改变与冠根比(crown-to-implant ratio,CIR)关系。结果:纳入研究的69枚Bicon种植体,经过(65±9)个月的功能负载,成功率为94.2%。按CIR进行分组,MBL、△GSV与CIR之间未发现显著相关(P>0.05);仅有2枚植体发生崩瓷,机械并发症比较差异无统计学意义(P>0.05)。结论:Bicon短种植体CIR对种植体周MBL、GSV改变没有明显影响,骨组织具有足够的改建活性以应对更大的应力刺激。高CIR未导致更多的机械并发症和种植体失败。
