A new pentaborate, KNa2CdB5O（10）, has been synthesized and its crystal structure was determined by single-crystal XRD method with the following crystal data： KNa2CdB5O（10）, Pccn, a = 18.4555（13）, b = 8.3040（10...A new pentaborate, KNa2CdB5O（10）, has been synthesized and its crystal structure was determined by single-crystal XRD method with the following crystal data： KNa2CdB5O（10）, Pccn, a = 18.4555（13）, b = 8.3040（10）, c = 12.8772（9） A, V = 1973.5（3） A3, Z = 8, Mr = 411.53, Dc= 2.770 g/cm3, μ = 2.765 mm（-1）, F（000） = 1552, R = 0.0648 and w R = 0.1756 for 1684 observed reflections and 175 variables. It contains the double ring [B5O（10）]（5-） groups composed of one BO4 tetrahedron and four BO3 triangles that are bridged by tetrahedral Cd（2＋） centers via common O atoms to form 2D [CdB5O（10）]n（3n-） layers, with A＋（A = K/Na, Na） cations situated between and within the layers. IR spectrum confirms the existence of BO3 and BO4 groups. UV-VIS diffuse reflectance spectrum shows a band gap of about 3.44 eV and solid-state fluorescence spectrum exhibits a broad emission band at around 386 nm. Band structure calculations indicate that KNa2CdB5O（10） is an indirect band-gap insulator, with the calculated energy gap（3.68 eV） close to the experimental one.展开更多
CDB—f886型超声检诊仪系多普勒超声和 A 型超声(报警式)复合型仪器。我们于1989年6月到1990年10月试用此仪器通过直肠对239头蒙古牛进行了妊娠诊断。一、仪器和材料仪器:CDB—f886型兽用超声检诊仪一台,D 开关为多普勒、B 开关为 A 型...CDB—f886型超声检诊仪系多普勒超声和 A 型超声(报警式)复合型仪器。我们于1989年6月到1990年10月试用此仪器通过直肠对239头蒙古牛进行了妊娠诊断。一、仪器和材料仪器:CDB—f886型兽用超声检诊仪一台,D 开关为多普勒、B 开关为 A 型报警。展开更多
基金Supported by the National Natural Science Foundation of China(No.20871012)
文摘A new pentaborate, KNa2CdB5O（10）, has been synthesized and its crystal structure was determined by single-crystal XRD method with the following crystal data： KNa2CdB5O（10）, Pccn, a = 18.4555（13）, b = 8.3040（10）, c = 12.8772（9） A, V = 1973.5（3） A3, Z = 8, Mr = 411.53, Dc= 2.770 g/cm3, μ = 2.765 mm（-1）, F（000） = 1552, R = 0.0648 and w R = 0.1756 for 1684 observed reflections and 175 variables. It contains the double ring [B5O（10）]（5-） groups composed of one BO4 tetrahedron and four BO3 triangles that are bridged by tetrahedral Cd（2＋） centers via common O atoms to form 2D [CdB5O（10）]n（3n-） layers, with A＋（A = K/Na, Na） cations situated between and within the layers. IR spectrum confirms the existence of BO3 and BO4 groups. UV-VIS diffuse reflectance spectrum shows a band gap of about 3.44 eV and solid-state fluorescence spectrum exhibits a broad emission band at around 386 nm. Band structure calculations indicate that KNa2CdB5O（10） is an indirect band-gap insulator, with the calculated energy gap（3.68 eV） close to the experimental one.
基金the National Natural Science Foundation of China under Grant Nos.60603032,60604029(国家自然科学基金)the NSFC-Guangdong Province of China under Grant No.U0735003(国家自然科学基金委-广东省联合基金重点项目)
文摘针对当前弱硬实时调度算法无法保证超过窗口长度的执行序列的满足率达到一定比例的问题,基于(m^-,p)弱硬实时约束,提出了一种基于裁剪的调度算法(cut-down based scheduling,简称CDBS).由于判断(m^-,p)约束是否满足需要遍历任务的整个执行序列,因此判断复杂度很大.为此,提出一种高效的裁剪执行序列的算法,同时证明其正确性,并利用适当的数据结构,使得计算复杂度与序列长度无关,通过实验说明其降低计算复杂度的有效性.进一步与其他经典实时调度算法(EDF(earliest deadline first),DBP(distance-based priority),DWCS(dynamic window constraint schedule))进行比较,验证该算法与其他算法具有相当的性能.
