从讨论非对称二分查找树的平衡问题出发,给出了一种通用的平衡权函数构造方法,解决了Waldvogel等在算法优化过程中提出的启发式平衡权函数构造问题,优化了非对称二分查找树平衡算法,使得CHT(col-lection of hash tables)算法很容易扩展...从讨论非对称二分查找树的平衡问题出发,给出了一种通用的平衡权函数构造方法,解决了Waldvogel等在算法优化过程中提出的启发式平衡权函数构造问题,优化了非对称二分查找树平衡算法,使得CHT(col-lection of hash tables)算法很容易扩展到128 bit的IPv6地址.实验表明,该算法与Waldvogel等在特殊情况下给出的推测结果基本符合,能很好地适应IP前缀分布的变化,具有很好的适应性和可扩展性.展开更多
Mg/Al mixed oxides with molar ratios of 2_6 of Mg to Al used as supports for platinum catalysts were obtained by the thermal decomposition method. The effect of the composition of the mixed oxides on the physicochemic...Mg/Al mixed oxides with molar ratios of 2_6 of Mg to Al used as supports for platinum catalysts were obtained by the thermal decomposition method. The effect of the composition of the mixed oxides on the physicochemical properties was studied by TPD, nitrogen sorption, XRD and TG-DTA characterization methods. The synthesis of o-phenylphenol(OPP) from a dimer(obtained from cyclohexanone condensation) was investigated over Pt/CHT catalysts and compared with those over Pt/MgO and Pt/Al 2O 3 catalysts. These catalysts show a high activity and selectivity for OPP, with a conversion reaching 93.8% and a selectivity reaching 87.9% in some experiments. For Pt/CHTx catalysts, the calcined hydrotalcites exhibited strong base sites, which were necessary to catalyze the synthesis of OPP.展开更多
Bangladesh has achieved notable progress in expanding electricity access nationwide.Nonetheless,remote and topographically challenging regions such as the Chittagong Hill Tracts(CHT)continue to face coverage gaps due ...Bangladesh has achieved notable progress in expanding electricity access nationwide.Nonetheless,remote and topographically challenging regions such as the Chittagong Hill Tracts(CHT)continue to face coverage gaps due to grid extension difficulties.This research investigates the technical feasibility of micro-hydro power(MHP)systems as viable off-grid solutions for rural electrification in CHT.Field surveys conducted across various sites assessed available head and flow rates using GPS-based elevation measurements and portable flowmeters.Seasonal fluctuations were factored into the analysis to ensure year-round operational viability.The study involved estimating power output,selecting appropriate turbine types based on head-flow data,and proposing preliminary plant configurations.Results identify multiple locations with adequate head(2.5 to 10.4 m)and flow rates(0.10 to 0.35 m3/s),capable of generating between 1.5 and 16.5 kW,sufficient for essential rural applications.Based on site-specific head and discharge characteristics,Kaplan and Francis turbines were identified as the most suitable configurations,offering high efficiency for the medium-flow,low-to-medium head environments typical of the studied regions.Despite inherent technical potential,challenges such as seasonal variability,infrastructure complexities,and policy deficiencies remain.This investigation addresses a critical knowledge gap in local renewable energy planning.It offers a data-driven foundation for pilot projects and community-scale electrification initiatives in Bangladesh’s remote mountainous areas.展开更多
文摘从讨论非对称二分查找树的平衡问题出发,给出了一种通用的平衡权函数构造方法,解决了Waldvogel等在算法优化过程中提出的启发式平衡权函数构造问题,优化了非对称二分查找树平衡算法,使得CHT(col-lection of hash tables)算法很容易扩展到128 bit的IPv6地址.实验表明,该算法与Waldvogel等在特殊情况下给出的推测结果基本符合,能很好地适应IP前缀分布的变化,具有很好的适应性和可扩展性.
文摘Mg/Al mixed oxides with molar ratios of 2_6 of Mg to Al used as supports for platinum catalysts were obtained by the thermal decomposition method. The effect of the composition of the mixed oxides on the physicochemical properties was studied by TPD, nitrogen sorption, XRD and TG-DTA characterization methods. The synthesis of o-phenylphenol(OPP) from a dimer(obtained from cyclohexanone condensation) was investigated over Pt/CHT catalysts and compared with those over Pt/MgO and Pt/Al 2O 3 catalysts. These catalysts show a high activity and selectivity for OPP, with a conversion reaching 93.8% and a selectivity reaching 87.9% in some experiments. For Pt/CHTx catalysts, the calcined hydrotalcites exhibited strong base sites, which were necessary to catalyze the synthesis of OPP.
文摘Bangladesh has achieved notable progress in expanding electricity access nationwide.Nonetheless,remote and topographically challenging regions such as the Chittagong Hill Tracts(CHT)continue to face coverage gaps due to grid extension difficulties.This research investigates the technical feasibility of micro-hydro power(MHP)systems as viable off-grid solutions for rural electrification in CHT.Field surveys conducted across various sites assessed available head and flow rates using GPS-based elevation measurements and portable flowmeters.Seasonal fluctuations were factored into the analysis to ensure year-round operational viability.The study involved estimating power output,selecting appropriate turbine types based on head-flow data,and proposing preliminary plant configurations.Results identify multiple locations with adequate head(2.5 to 10.4 m)and flow rates(0.10 to 0.35 m3/s),capable of generating between 1.5 and 16.5 kW,sufficient for essential rural applications.Based on site-specific head and discharge characteristics,Kaplan and Francis turbines were identified as the most suitable configurations,offering high efficiency for the medium-flow,low-to-medium head environments typical of the studied regions.Despite inherent technical potential,challenges such as seasonal variability,infrastructure complexities,and policy deficiencies remain.This investigation addresses a critical knowledge gap in local renewable energy planning.It offers a data-driven foundation for pilot projects and community-scale electrification initiatives in Bangladesh’s remote mountainous areas.
