一种求解不定信赖域子问题的双割线折线法

结合利用Hessian阵的特征值性质,针对Bk是不定的情况,提出了一种双割线折线法来求解不定的信赖域子问题,并从理论上分析了当Bk不定时,双割线折线路径的合理性,且给出了算法的收敛性质。最后,详细的数值试验表明,算法是有效的。     

溶胶-凝胶法合成Sr2SiO4:Dy3+粉体及发光性能

采用溶胶-凝胶法合成了Sr2SiO4:Dy3+粉体.用热重-差热(TG-DSC)、X射线衍射(XRD)、扫描电镜(SEM)等表征了样品的结构、形貌,研究了Dy掺杂浓度和Dy与Li的摩尔比对发光强度的影响.结果表明,所得样品为单斜晶系结构,呈长为800 nm的纤维状小颗粒,其发射光谱为一个多峰宽谱,主峰分别为480,571和661 nm;监测571 nm的发射峰,所得材料的激发光谱为一个多峰宽谱,主峰分别为327,352,366,391,429,453和478 nm;当Dy3+的掺杂浓度(摩尔分数)为4%,Dy与Li的摩尔比为1:1时,样品的发光强度最强.     

三峡水库综合利用调度关键技术研究与实践

为全面提升三峡工程的综合利用效益,三峡水库蓄水以来对规划设计的水库调度方式进行了优化研究与实践。文章对其关键技术进行分析总结,主要有协调防洪、发电、航运、供水和生态等多目标需求的技术、调度风险控制技术、调度决策优化技术、编制调度规程以规范调度工作等。通过分析以寻求不断完善三峡水库综合利用调度方式的路径,力求实现三峡工程效益最优,成为环境友好且对社会公益性贡献突出的跨世纪宏伟工程。     

改进型感应电机电压模型磁链观测器设计

针对传统电压模型磁链观测器中引入低通滤波器后,带来幅值相位误差及滤波最佳截止频率选择问题,本文提出了一种高通滤波器和低通滤波器串联,且对电压模型中的电压项和电流项分别积分的改进型电压模型转子磁链观测器.文中分析了该改进型磁链观测器性能提高的原因,推导了高通滤波器和低通滤波器引起的幅值和相位误差补偿算法.仿真和实验验证了补偿算法的有效性,并且新的改进型转子磁链观测器在电机全速范围内具有优良的稳态和动态性能,具有较高的工程实践价值.     

高新技术企业内部研发投入产出效果分析与实证研究

针对高新技术企业内部研发投入产出效果的提升问题,本文从研发投入内部来源的角度进行考虑,以广州市某区高新技术企业2014-2016年的统计数据为基础,采用实证研究方法,试图构建该区高新技术企业内部研发投入与产出的关系模型,根据最终研究结果进行分析总结,从而得出一些有用的结论。     

向量优化问题弱E-有效解的代数性质

【目的】研究一类集值向量优化问题。【方法】利用代数内部这一概念,建立基于改进集而定义的集值映射邻近E-次似凸性的择一性定理,进而应用该定理来研究集值向量优化问题。【结果】给出了基于代数内部和改进集而定义的弱 E-有效解的线性标量化结果和拉格朗日乘子定理,同时也给出了一些例子并对主要结果进行了解释。【结论】主要结果是对最近一些文献中相应结果的改进与推广。
     

CuO/C催化剂的制备及其脱除烟气中NO的研究

以褐煤为原料,先通过干馏、活化的方法制取活性半焦,再采用水热法在活性半焦上负载CuO制备CuO/C催化剂,利用XRD和SEM等技术对其晶体结构和微观形貌进行表征,并分析CuO/C催化剂对模拟烟气中NO脱除效果的影响因素。结果表明,活性半焦含有丰富的含氧官能团,是一种较好的催化剂载体和还原剂;在120℃和2h的制备条件下制备CuO/C催化剂时,在活性半焦表面生长的CuO晶体较多,尺寸较小且分散均匀;当C-NO的反应温度为250℃、空速为19 200h~(-1)、氧气含量为4%时,在120℃和2h制备条件下所制得的CuO/C催化剂对NO脱除效果好,其NO脱除率可达95.26%。     

Comparative study on the corrosion behavior of X52, 3Cr,and 13Cr steel in an O2–H2O–CO2 system: products,reaction kinetics,and pitting sensitivity

The corrosionbehaviors of X52, 3Cr low-alloy steel, and 13Cr stainless steel were investigated inanO2–H2O–CO2 environment at varioustemperaturesand O2–CO2partial-pressure ratios. The results showed thatthe corrosion rates of X52, 3Cr, and 13Cr steels in-creased with increasing temperature. The corrosion ratesslowly increased at temperaturesless than100℃ and increased sharply when the temperature exceeded100℃. In the absence of O2, X52, 3Cr, and 13Cr exhibited uniform corrosion morphology and FeCO3 was the main corrosion product. When O2 was introduced into the system, various forms of Fe2O3 appeared on the surface of the samples. The Cr content strongly influenced the corrosion resistance. The 3Cr steel with a low Cr content was more sensitive to pitting than the X52 or 13Cr steel. Thus, pitting occurred on the surface of 3Cr when 1.25 MPa of O2 was added; this phenomenon is related to the non-uniform distribution of Cr in 3Cr.     

Tunable multiple-channel filters based on photonic heterostructures using single-negative materials

We studied the multiple-channel filters based on photonic heterostructures consisting of single-negative permittivity and single-negative permeability media. The results showed that the number of resonance modes inside the zero-φeff gap increases as the number of heterogenous interface M increases. The number of resonance modes inside the zero-φeff, gap is equal to that of heterogenous interface M, and it can be used as M channels filter. This result provides a feasible method to adjust the channel number of multiple-channel filters. When losses are involved, the results showed that the electric fields of the resonance modes decay largely with the increase of the number of heterogenous interface and damping factors. Besides, the relationship between the quality factor of multiple-channel filters and the number of heterogenous interface M is linear, and the quality factor of multiple-channel filters decreases with the increase of the damping factor. These results provide feasible methods to adjust the quality factor of multiple-channel filters.     

Pulleniatina Minimum Event during the last deglaciation in the southern South China Sea

The planktonic foraminiferal faunal census of core MD 05-2894 （7°2.25′N, 111°33.11′E, water depth 1982 m）, retrieved from the southern South China Sea （SCS） during the ＂Marco Polo＂ cruise in 2005, was performed to investigate the abundance changes of a subsurface dweller, Pulleniatina obliquiloculata. The results display that the abundance of P. obliquiloculata nearly declines to zero during 16.0--14.9 ka, corresponding to the Heinrich 1 （H1） cold interval. The unexpected decrease of P. obliquiloculata occurs in the adjacent cores, roughly between 17 and 14.8 ka based on the previous studies. Accordingly, the Pulleniatina Minimum Event in the last deglaciation can serve as a good stratigraphical indicator, at least in the southern SCS. To further explore the changes of sea surface temperature （SST） and subsurface seawater temperature （SSST）, we made parallel Mg/Ca measurements on surface dweller Globigerinoides tuber and subsurface dweller P. obliquiloculata tests. Since the last deglaciation, the SSTs show a continuous increasing trend towards the late Holocene, while the warming of the subsurface water is punctuated by a 2℃-cooling interval across the deglacial Pulleniatina Minimum Event. Both increased 5180 differences between G. ruber and P. obliquiloculata, and increased temperature differences between surface and subsurface water suggest a shoaling of the mixed layer during the deglacial Pulleniatina Minimum Event. Therefore, we consider that the significant changes in the upper ocean structure are responsible for the Pulleniatina Minimum Event during the last deglaciation in the southern SCS.