数据特性和硬件特征是高效数据管理的两个关键因素.一方面,随着大数据时代的到来,数据管理系统需要支持越来越海量、高速、多样的数据.各种新的数据管理技术纷纷涌现,不仅包括对传统的关系型数据库系统的扩展,而且包括多种新型的大数据...数据特性和硬件特征是高效数据管理的两个关键因素.一方面,随着大数据时代的到来,数据管理系统需要支持越来越海量、高速、多样的数据.各种新的数据管理技术纷纷涌现,不仅包括对传统的关系型数据库系统的扩展,而且包括多种新型的大数据系统,例如N oS Q L系统、N ew SQ L系统等.数据的种类不仅有传统的关系型数据,而且有图类型、J S O N树状数据等多种非传统数据类型.另一方面,计算机系统的硬件正在经历着深远的变化.更大容量的主存、N V M技术等正改变着存储系统的面貌.GPU、FPGA、专用加速硬件正逐渐由专用领域走向通用计算,对数据的运算和管理发挥着越来越重要的影响.因此,如何把这两者相结合,利用新型的存储和计算硬件高效地支持数据管理的需求成为一个重要的学术课题.许多基本问题还有待探索,包括系统架构、数据存储、索引、查询处理、能源效率等.展开更多
A BiOCl-Bi12O17Cl2 nanocomposite with a high visible-light response and a low photoinduced electron-hole pair recombination rate was successfully synthesized using an ultrasonic-hydrothermal method.The texture,structu...A BiOCl-Bi12O17Cl2 nanocomposite with a high visible-light response and a low photoinduced electron-hole pair recombination rate was successfully synthesized using an ultrasonic-hydrothermal method.The texture,structure,optical,and photocatalytic properties of the composite were characterized.The results showed that the composite had a sheet flower-like structure with a large specific surface area.Ultraviolet-visible diffuse reflection spectra and photoluminescence spectra showed that the composite had an excellent visible-light response and a low recombination rate of photoinduced electron hole pairs.The photocatalytic property of the composite was evaluated by the removal efficiency of rhodamine B and ciprofloxacin under visible-light illumination.The composite’s reaction rate constant of removing rhodamine B(/ciprofloxacin)was approximately 8.14(/4.94),42.63(/11.91)and 64.66(/36.07)times that of Bi12O17Cl2,P25,and BiOCl,respectively.Furthermore,the composite showed a wide applicable pH range and excellent reusability.Mechanism analysis showed that photogenerated holes played a dominant role and·O2–also contributed to photocatalytic degradation.In summary,this study presents a high-efficiency photocatalyst for wastewater treatment.展开更多
文摘数据特性和硬件特征是高效数据管理的两个关键因素.一方面,随着大数据时代的到来,数据管理系统需要支持越来越海量、高速、多样的数据.各种新的数据管理技术纷纷涌现,不仅包括对传统的关系型数据库系统的扩展,而且包括多种新型的大数据系统,例如N oS Q L系统、N ew SQ L系统等.数据的种类不仅有传统的关系型数据,而且有图类型、J S O N树状数据等多种非传统数据类型.另一方面,计算机系统的硬件正在经历着深远的变化.更大容量的主存、N V M技术等正改变着存储系统的面貌.GPU、FPGA、专用加速硬件正逐渐由专用领域走向通用计算,对数据的运算和管理发挥着越来越重要的影响.因此,如何把这两者相结合,利用新型的存储和计算硬件高效地支持数据管理的需求成为一个重要的学术课题.许多基本问题还有待探索,包括系统架构、数据存储、索引、查询处理、能源效率等.
基金supported by National Water Pollution Control and Treatment Science and Technology Major Project(2018ZX07110003)Key Research and Development Project of Shandong Province(2018CXGC1007)~~
文摘A BiOCl-Bi12O17Cl2 nanocomposite with a high visible-light response and a low photoinduced electron-hole pair recombination rate was successfully synthesized using an ultrasonic-hydrothermal method.The texture,structure,optical,and photocatalytic properties of the composite were characterized.The results showed that the composite had a sheet flower-like structure with a large specific surface area.Ultraviolet-visible diffuse reflection spectra and photoluminescence spectra showed that the composite had an excellent visible-light response and a low recombination rate of photoinduced electron hole pairs.The photocatalytic property of the composite was evaluated by the removal efficiency of rhodamine B and ciprofloxacin under visible-light illumination.The composite’s reaction rate constant of removing rhodamine B(/ciprofloxacin)was approximately 8.14(/4.94),42.63(/11.91)and 64.66(/36.07)times that of Bi12O17Cl2,P25,and BiOCl,respectively.Furthermore,the composite showed a wide applicable pH range and excellent reusability.Mechanism analysis showed that photogenerated holes played a dominant role and·O2–also contributed to photocatalytic degradation.In summary,this study presents a high-efficiency photocatalyst for wastewater treatment.
