组合离子注入的杂质浓度分布与损伤分布比较

用LSS理论,计算了注入能量为180keV,注入剂量为1×10~(13)～5×10~(15)ion/cm~2的N_2~ /As~ 组合离子注人Si的杂质浓度分布,由X射线衍射的运动学理论,利用多层模型和试探应变函数拟合X射线衍射曲线,得到了晶格应变随注入深度的分布,并将二者进行了比较.结果表明N_2~ /As~ 组合离子注入单晶Si的应变分布曲线为单峰,位于杂质浓度分布曲线的双峰之间,靠近重离子峰.     

三明治链型有机金属化合物的结构与化学键

关于三明治链型有机金属化合物中的〔Pd4(DPOT) 2 〕2 +、〔Pd4(DPOT) 2 (NC5H5) 2 〕2 +两个离子的成键问题 ,吸取了现代理论和方法的成就 ,对上述两个离子的成键情况进行了分析 ,结果非常令人满意 .     

氮转化的生化调控对蔬菜生长及土壤质量的影响

采用微区试验方法,研究了温室栽培条件下新型脲酶抑制LNS、硝化抑制剂双氰胺(DCD)与尿素配合施用对蔬菜产量、品质及菜田土壤pH、电导率的影响.结果表明,两种抑制剂配合施用对芹菜产量和Vc含量影响不大,但却显著降低了芹菜的硝酸盐含量,提高了下茬生菜产量.一季氮肥的施用就使温室土壤表现出了明显的酸化和盐分表积趋势,但两种抑制剂与尿素配合施用可以使土壤酸化程度明显减缓.芹菜定植后1个月时,U UI NI处理的土壤pH与U和U UI相比,分别提高了0.7和0.52个pH单位,差异极显著(P < 0.01);第二茬生菜收获后,土壤电导率值与二者相比,分别降低了17.67%和17.00%.因此,脲酶和硝化抑制剂配合施用调控氮素转化可能是缓解设施农业生产中的土壤酸化和次生盐渍化、降低蔬菜硝酸盐含量的一项有效措施.     

动态耦合度的定义与表示

介绍了多变量系统动态耦合度的定义及其简化表示,以及与之相关的变量配对原则。最后,对已解耦和未解耦系统的动态耦合度进行了仿真比较。     

Efficient multiuser detector based on box-constrained deregularization and its FPGA design

Multiuser detection can be described as a quadratic optimization problem with binary constraint.Many techniques are available to find approximate solution to this problem.These techniques can be characterized in terms of complexity and detection performance.The "efficient frontier" of known techniques include the decision-feedback,branch-and-bound and probabilistic data association detectors.The presented iterative multiuser detection technique is based on joint deregularized and box-constrained solution to quadratic optimization with iterations similar to that used in the nonstationary Tikhonov iterated algorithm.The deregularization maximizes the energy of the solution,this is opposite to the Tikhonov regularization where the energy is minimized.However,combined with box-constraints,the deregularization forces the solution to be close to the binary set.We further exploit the boxconstrained dichotomous coordinate descent (DCD) algorithm and adapt it to the nonstationary iterative Tikhonov regularization to present an efficient detector.As a result,the worst-case and average complexity are reduced down to 2.8 and 2.5 floating point operation per second,respectively.The development improves the "efficient frontier" in multiuser detection,which is illustrated by simulation results.Finally,a field programmable gate array (FPGA) design of the detector is presented.The detection performance obtained from the fixed-point FPGA implementation shows a good match to the floating-point implementation.