Multihull ships are widely used for sea transportation, and those with four hulls are known as quadramarans. Hull position configurations of a quadramaran include the diamond, tetra, and slice. In general, multihull v...Multihull ships are widely used for sea transportation, and those with four hulls are known as quadramarans. Hull position configurations of a quadramaran include the diamond, tetra, and slice. In general, multihull vessels traveling at high speeds have better hydrodynamic efficiency than monohull ships. This study aims to identify possible effects of various quadramaran hull position configurations on ship resistance for hull dimensions of 2 m length, 0.21 m breadth, and 0.045 m thickness. We conducted a towing test in which we varied the hull spacing and speed at Fr values between 0.08 and 0.62 and measured the total resistance using a load cell transducer. The experimental results reveal that the lowest total resistance was achieved with a diamond quadramaran configuration at Fr = 0.1-0.6 and an effective interference factor of up to 0.35 with S/L = 3/10 and R/L = 1/2 at Fr = 0.62.展开更多
Y^3＋-doped （Bi 1/2 Na 1/2） TiO 3-CaTiO 3-BaTiO 3 （BNCBT） positive temperature coefficient of resistivity （PTCR） ceramics sintered in air atmosphere were investigated in this study. （Bi 1/2 Na 1/2） TiO 3 （BNT...Y^3＋-doped （Bi 1/2 Na 1/2） TiO 3-CaTiO 3-BaTiO 3 （BNCBT） positive temperature coefficient of resistivity （PTCR） ceramics sintered in air atmosphere were investigated in this study. （Bi 1/2 Na 1/2） TiO 3 （BNT） component can remarkably increase the onset temperature T c of PTCR ceramics with the expense of the resistivity R 25 increase. CaTiO 3 （9–27 mol%） component can decrease the resistivity, and adjust the effects of BNT phase on the T c point. For the sample containing 3 mol% CaTiO 3 , T c raises from 122 ℃ to 153 ℃ when only 0.6 mol% BNT added, while for the ones with higher CaTiO 3 content （9–27 mol%）, T c is only increased by a rate of 8–9℃/1.0 mol% BNT. The effects of BNT and CaTiO 3 components on R25/Rmin （negative temperature coefficient effect） are also discussed.展开更多
High-density polyethylene/carbon black foaming conductive composites were prepared from acetylene black（ACEY） and super conductive carbon black（HG-1P） as conductive filler, low-density polyethylene（LDPE） as the ...High-density polyethylene/carbon black foaming conductive composites were prepared from acetylene black（ACEY） and super conductive carbon black（HG-1P） as conductive filler, low-density polyethylene（LDPE） as the second component, ethylene-vinyl acetate（EVA） and ethylene propylene rubber（EPR） as the third component, azobisformamide（AC） as foamer, and dicumyl peroxide（DCP） as cross-linker. The structure and resistivity-temperature behavior of high-density polyethylene（HDPE）/CB foaming conductive composites were investigated. Influences of carbon black, LDPE, EVA, EPR, AC, and DCP on the foaming performance and resistivity-temperature behavior of HDPE/CB foaming conductive composites were also studied. The results reveal that HDPE/CB foaming conductive composite exhibits better switching characteristic; ACET-filled HDPE foaming conductive composite displays better positive temperature coefficient（PYC） effect; whereas super conductive carbon black（HG-1P）-filled HDPE foaming conductive composite shows better negative temperature coefficient（NTC） effect.展开更多
目的不同的体位对血流动力学和呼吸均有正向和负向的生理作用。本研究旨在进行文献综述并探讨不同体位的血流动力学和呼吸变化。方法研究方案在国际前瞻性系统评价登记处注册(注册号:CRD42021291464)。两名独立研究人员使用Down and Bl...目的不同的体位对血流动力学和呼吸均有正向和负向的生理作用。本研究旨在进行文献综述并探讨不同体位的血流动力学和呼吸变化。方法研究方案在国际前瞻性系统评价登记处注册(注册号:CRD42021291464)。两名独立研究人员使用Down and Black检查表评估了所有纳入研究的方法学质量,而证据质量的评估则基于“推荐意见分级的评估、制定及评价”(Grading of Recommendations,Assessment,Development,and Evaluations,GRADE)。通过随机效应荟萃分析报告了不同体位的总体效果。结果3项低偏倚风险研究和10项高偏倚风险研究符合纳入标准。与70度直立倾斜位、坐位和站姿相比,仰卧位的心输出量最高(极低至中等质量的证据);与70度直立倾斜位和站姿相比,仰卧位的全身血管阻力最低(中等质量证据)。此外,与70度直立倾斜位、左侧和站姿相比,仰卧位的总呼吸阻力最高(极低至中等质量的证据),而其肺泡通气量则高于俯卧位(低质量证据)。结论仰卧位与血流动力学变量的正相关性最高,相对应的心输出量最高、全身血管阻力最低。直立体位(70度直立倾斜位和站姿)与呼吸变量的正相关性最高,相对应地总呼吸阻力最低。展开更多
基金sponsored by the Directorate of Research and Community Services,University of Indonesia(Hibah PUPT-Tambahan UI 2015)
文摘Multihull ships are widely used for sea transportation, and those with four hulls are known as quadramarans. Hull position configurations of a quadramaran include the diamond, tetra, and slice. In general, multihull vessels traveling at high speeds have better hydrodynamic efficiency than monohull ships. This study aims to identify possible effects of various quadramaran hull position configurations on ship resistance for hull dimensions of 2 m length, 0.21 m breadth, and 0.045 m thickness. We conducted a towing test in which we varied the hull spacing and speed at Fr values between 0.08 and 0.62 and measured the total resistance using a load cell transducer. The experimental results reveal that the lowest total resistance was achieved with a diamond quadramaran configuration at Fr = 0.1-0.6 and an effective interference factor of up to 0.35 with S/L = 3/10 and R/L = 1/2 at Fr = 0.62.
基金Project supported by the SPAT of Shanghai Committee of Chinese People's Political Consultative Conference and Shanghai Education Development Foundation (Grant No.2008012)
文摘Y^3＋-doped （Bi 1/2 Na 1/2） TiO 3-CaTiO 3-BaTiO 3 （BNCBT） positive temperature coefficient of resistivity （PTCR） ceramics sintered in air atmosphere were investigated in this study. （Bi 1/2 Na 1/2） TiO 3 （BNT） component can remarkably increase the onset temperature T c of PTCR ceramics with the expense of the resistivity R 25 increase. CaTiO 3 （9–27 mol%） component can decrease the resistivity, and adjust the effects of BNT phase on the T c point. For the sample containing 3 mol% CaTiO 3 , T c raises from 122 ℃ to 153 ℃ when only 0.6 mol% BNT added, while for the ones with higher CaTiO 3 content （9–27 mol%）, T c is only increased by a rate of 8–9℃/1.0 mol% BNT. The effects of BNT and CaTiO 3 components on R25/Rmin （negative temperature coefficient effect） are also discussed.
文摘High-density polyethylene/carbon black foaming conductive composites were prepared from acetylene black（ACEY） and super conductive carbon black（HG-1P） as conductive filler, low-density polyethylene（LDPE） as the second component, ethylene-vinyl acetate（EVA） and ethylene propylene rubber（EPR） as the third component, azobisformamide（AC） as foamer, and dicumyl peroxide（DCP） as cross-linker. The structure and resistivity-temperature behavior of high-density polyethylene（HDPE）/CB foaming conductive composites were investigated. Influences of carbon black, LDPE, EVA, EPR, AC, and DCP on the foaming performance and resistivity-temperature behavior of HDPE/CB foaming conductive composites were also studied. The results reveal that HDPE/CB foaming conductive composite exhibits better switching characteristic; ACET-filled HDPE foaming conductive composite displays better positive temperature coefficient（PYC） effect; whereas super conductive carbon black（HG-1P）-filled HDPE foaming conductive composite shows better negative temperature coefficient（NTC） effect.
文摘目的不同的体位对血流动力学和呼吸均有正向和负向的生理作用。本研究旨在进行文献综述并探讨不同体位的血流动力学和呼吸变化。方法研究方案在国际前瞻性系统评价登记处注册(注册号:CRD42021291464)。两名独立研究人员使用Down and Black检查表评估了所有纳入研究的方法学质量,而证据质量的评估则基于“推荐意见分级的评估、制定及评价”(Grading of Recommendations,Assessment,Development,and Evaluations,GRADE)。通过随机效应荟萃分析报告了不同体位的总体效果。结果3项低偏倚风险研究和10项高偏倚风险研究符合纳入标准。与70度直立倾斜位、坐位和站姿相比,仰卧位的心输出量最高(极低至中等质量的证据);与70度直立倾斜位和站姿相比,仰卧位的全身血管阻力最低(中等质量证据)。此外,与70度直立倾斜位、左侧和站姿相比,仰卧位的总呼吸阻力最高(极低至中等质量的证据),而其肺泡通气量则高于俯卧位(低质量证据)。结论仰卧位与血流动力学变量的正相关性最高,相对应的心输出量最高、全身血管阻力最低。直立体位(70度直立倾斜位和站姿)与呼吸变量的正相关性最高,相对应地总呼吸阻力最低。
