铬酸钠碳氨转化过程的相图分析

研究了铬酸钠碳氨转化过程中Na＋, NH4+// CrO42－, HCO3－-H2O体系的溶解度和相图.根据溶解度和相图对铬酸钠的氨水溶液碳氨转化过程固相析出行为进行分析.结果表明: 相图中存在NaNH4CrO4·2H2O复盐结晶区,浓度较高的铬酸钠氨水溶液转化过程中NaC(HO)3、(NH4)2CrO4和NaNH4CrO4·2H2O结晶可能同时析出,形成混晶.为避免同时析出铬酸铵、碳酸氢钠结晶,铬酸钠氨水初始溶液浓度应稍低于相图中P2(P2′)对应的组成,即为1 g H2O中Na2CrO4 0.8633～1.1377 g,氨0.0611～0.0986 g.     

稻杆的热溶剂提质及多级分离

采用1-甲基萘(1-MN)为溶剂,在不同温度下(250、300、350 ℃)对稻秆进行热溶剂提质及多级分离,获得3种主要固体产物:低分子量萃取物(soluble)、高分子量萃取物(deposit)和萃取残渣(residue),以及少量气体产物和液体产物。对各组分的元素组成、化学结构、物理化学特性等进行了详细分析,并采用ICP-MS测定了其碱金属和碱土金属(AAEM)含量。结果发现,低分子量萃取物收率随着温度的升高而增大,350 ℃时碳基收率达到33.48%。3种固体产物的碳含量和氧含量随着温度的升高而分别升高和降低,350 ℃时soluble、deposit的碳含量分别高达82.36%、80.59%,氧含量分别低至9.50%、12.03%,稻杆原样中高达86.99%的氧以H₂O或CO₂的形式释放。soluble几乎无灰,deposit的灰含量也低于1.50%。3种固体产物的高位发热量显著高于稻杆原样。FT-IR结果表明,稻杆热溶剂处理过程中除发生了脱水反应、脱羧基反应外,还有明显的芳香化反应。soluble和deposit的Na、Mg和K含量极低,而且随温度的升高其含量逐渐降低。总之,热溶剂提质及多级分离法实现了温和条件下的生物质脱水脱氧提质,并获得低灰低氧含量、高碳含量和发热量的多种产物,此方法有较好的应用前景。     

含旋流圆环形管道声传播的有限元计算

本文发展了计算包含旋流的圆环形管道声传播问题的有限元数值模型,并且对等熵和均熵流动做了讨论.经典的声学有限元方法大多求解只包含一个变量的对流波动方程,但是对于包含旋流等非均匀流的圆环形管道声传播问题,不能简化成只含有一个变量的对流波动方程.本文尝试用直接求解耦合方程组的有限元方法方法研究管道声传播问题.文章分别研究了刚性壁面、不同阻抗的声衬壁面对管道声传播的影响,同时还对不同阶的声模态包括传播模态和截止模态在管道中的传播规律做了分析.计算的结果和正模态解析方法符合得很好,从而验证了有限元模型的正确性和可行性.     

Software alignment of the BESⅢ main drift chamber using the Kalman Filter method

Software alignment is quite important for a tracking detector to reach its ultimate position accuracy and momentum resolution. We developed a new alignment algorithm for the BESⅢ Main Drift Chamber using the Kalman Filter method. Two different types of data which are helix tracks and straight tracks are used to test this algorithm, and the results show that the design and implementation is successful.     

加权Bergman空间上的约化子空间

主要证明在加权Bergman空间上符号为有限Blaskchke乘积的解析Toeplitz算子总是可约的,即至少有一个约化子空间.并且把该算子限制在该子空间上酉等价于加权Bergman位移.     

槐枝中总黄酮的含量测定

采用索氏提取法提取槐枝中的总黄酮,芦丁为对照,分光光度法测定其含量。样品浓度在16.104—96.624μg.mL-1范围内线性关系良好,相关系数r=0.9996。该方法简便、准确,可用于槐枝中总黄酮的含量测定。     

Calibration of RPC-based muon detector at BESⅢ

The calibration algorithm for RPC-based muon detector at BESIII has been developed. The calibration method, calibration error and algorithm performance are studied. The primary results of efficiency and noise at layer, module and strip levels have been calibrated with cosmic ray data. The calibration constants are available for simulation and reconstruction tuning. The results of Monte Carlo and data are also compared to check the validation and reliability of the algorithm.     

精确的堆内存使用量上界分析

基于符号执行框架分析了程序堆内存使用量的符号化上界.首先扩展了经典符号执行技术中的内存模型,针对堆内存分配与释放操作进行建模,维护堆内存的使用量信息,然后针对＂平板循环＂、带分支循环等常见循环结构给出了特殊处理策略,并采用程序切片技术缩减程序分析的规模.最后基于开源符号执行工具KLEE设计实现了一个堆内存使用量上界分析原型工具.实验结果证明,该工具能够针对很多常见程序给出精确可靠的堆内存使用量上界.     

Spin-controlled directional launching of surface plasmons at the subwavelength scale

In this paper, we demonstrate a spin-controlled directional launching of surface plasmons at the subwavelength scale.Based on the principle of optical spin's effect for the geometric phase of light, the nanostructures were designed. The inclination of the structures decides the spin-related geometric phase and their relative positions decide the distance-related phase. Hence, the propagation direction of the generated surface plasmon polaritons(SPPs) can be controlled by the spin of photons. Numerical simulations by the finite difference time domain(FDTD) method have verified our theoretical prediction. Our structure is fabricated on the Au film by using a focused ion beam etching technique. The total size of the surface plasmon polariton(SPP) launcher is 320 nm by 180 nm. The observation of the SPP launching by using scanning near-field optical microscopy is in agreement with our theory and simulations. This result may provide a new way of spin-controlled directional launching of SPP.     

迈克尔逊干涉在超短脉冲测量中的应用

分析了迈克尔逊干涉仪用于强度自相关测量超短脉冲的原理,设计了非共线结构迈克尔逊干涉仪,并利用二次谐波晶体对超短脉冲的强度自相关过程进行分辨,实现对超短脉冲的测量。