压力对超临界流体技术制备药物微粒的影响

研究了压力对乙基纤维素空白微粒粒径，以及阿莫西林-乙基纤维素-卡波谱缓释、黏附微粒性能的影响．实验表明乙基纤维素空白微粒和药物缓释、黏附微粒的粒径均随压力的升高而减小，但药物微粒的载药量和释放度曲线随压力的变化不明显。     

Use of an empirical probability generating function for testing a Poisson model

We present a test of the fit to a Poisson model based on the empirical probability generating function (epgf). We derive the limiting distribution of the test under the Poisson hypothesis and show that a rescaling of it is approximately independent of the mean parameter in the Poisson distribution. When inspected under a simulation study over a range of alternative distributions, we find that this test shows reasonable behaviour compared to other goodness-of-fit tests like the Poisson index of dispersion and smooth test applied to the Poisson model. These results illustrate that epgf-based methods for anlyzing count data are promising.     

填充等离子体介质切伦可夫脉塞的线性理论

在无引导磁场的作用下，利用自洽线性场理论，分析了电子的三维扰动速度和三维扰动电流密度对填充等离子体的介质切伦可夫脉塞注波互作用的影响，导出了注波互作用的色散关系和同步条件，所得关系清楚地表明，其工作用不稳定性是由填充等离子体的介质筒慢波波导中的ＴＭ模与电子注模通过电子注耦合所致，并求得了电子注引起的频偏和波的增长率。     

地方政府环境规制竞争背景下地区间的企业污染排放行为

针对地方政府环境规制竞争背景下中国污染排放空间异质性溢出问题,构建中国污染排放空间异质性溢出推拉模型,理论探讨中国区域污染排放在地方政府环境规制竞争背景下空间异质性溢出的形成机理:当由市场效应决定的拉力大于由学习效应决定的推力时,中国污染排放在空间上呈现负溢出效应;当由学习效应决定的推力大于由市场效应决定的拉力时,中国污染排放在空间上呈现正溢出效应。使用中国285个地级市2003-2015年数据,构建异质性空间自回归模型,使用准极大似然估计方法实证检验中国污染排放的空间异质性溢出特征。研究结果显示:（1）中国区域污染排放确实存在空间溢出效应,并且这种溢出效应呈现异质性特征。这种异质性是由不同区域内部不同的拉力与推力较量结果导致;（2）中国工业烟（粉）尘排放强度在空间上主要呈现出正的溢出效应,即中国大部分区域工业烟（粉）尘排放强度受学习效应影响。     

新时期以来中国少数民族文学现代性价值取向书写困局

新时期以来,伴随着现代化进程加快,少数民族文学陷入现代性价值取向的书写困局,日趋走向了一条反现代性或者说现代性的悖反之路.一方面在文化离散的伤感与困惑中,民族文学尝试以传统空间建构对抗现代性;另一方面,则企图通过反城市书写消解现代性侵袭从而确立新型民族身份.考察新时期以来民族文学书写症候并分析其根源,通过将现代性与民族性、全球化与本土化有机融合,重构少数民族文学现代性价值立场,是当下民族文学研究的一个重要方向.     

Interval estimation of the negative binomial dispersion parameter

Inference concerning the negative binomial dispersion parameter, denoted by c, is important in many biological and biomedical investigations. Properties of the maximum-likelihood estimator of c and its bias-corrected version have been studied extensively, mainly, in terms of bias and efficiency [W.W. Piegorsch, Maximum likelihood estimation for the negative binomial dispersion parameter, Biometrics 46 (1990), pp. 863–867; S.J. Clark and J.N. Perry, Estimation of the negative binomial parameter κ by maximum quasi-likelihood, Biometrics 45 (1989), pp. 309–316; K.K. Saha and S.R. Paul, Bias corrected maximum likelihood estimator of the negative binomial dispersion parameter, Biometrics 61 (2005), pp. 179–185]. However, not much work has been done on the construction of confidence intervals (C.I.s) for c. The purpose of this paper is to study the behaviour of some C.I. procedures for c. We study, by simulations, three Wald type C.I. procedures based on the asymptotic distribution of the method of moments estimate (mme), the maximum-likelihood estimate (mle) and the bias-corrected mle (bcmle) [K.K. Saha and S.R. Paul, Bias corrected maximum likelihood estimator of the negative binomial dispersion parameter, Biometrics 61 (2005), pp. 179–185] of c. All three methods show serious under-coverage. We further study parametric bootstrap procedures based on these estimates of c, which significantly improve the coverage probabilities. The bootstrap C.I.s based on the mle (Boot-MLE method) and the bcmle (Boot-BCM method) have coverages that are significantly better (empirical coverage close to the nominal coverage) than the corresponding bootstrap C.I. based on the mme, especially for small sample size and highly over-dispersed data. However, simulation results on lengths of the C.I.s show evidence that all three bootstrap procedures have larger average coverage lengths. Therefore, for practical data analysis, the bootstrap C.I. Boot-MLE or Boot-BCM should be used, although Boot-MLE method seems to be preferable over the Boot-BCM method in terms of both coverage and length. Furthermore, Boot-MLE needs less computation than Boot-BCM.     

Response surface design evaluation and comparison

Designing an experiment to fit a response surface model typically involves selecting among several candidate designs. There are often many competing criteria that could be considered in selecting the design, and practitioners are typically forced to make trade-offs between these objectives when choosing the final design. Traditional alphabetic optimality criteria are often used in evaluating and comparing competing designs. These optimality criteria are single-number summaries for quality properties of the design such as the precision with which the model parameters are estimated or the uncertainty associated with prediction. Other important considerations include the robustness of the design to model misspecification and potential problems arising from spurious or missing data. Several qualitative and quantitative properties of good response surface designs are discussed, and some of their important trade-offs are considered. Graphical methods for evaluating design performance for several important response surface problems are discussed and we show how these techniques can be used to compare competing designs. These graphical methods are generally superior to the simplistic summaries of alphabetic optimality criteria. Several special cases are considered, including robust parameter designs, split-plot designs, mixture experiment designs, and designs for generalized linear models.     

胶囊破胶剂的介质分散分相法制备研究

针对压裂施工过程中破胶过早的问题，以过硫酸铵为芯材，选用适宜的聚合物为囊衣材料，采用分散分相法制备胶囊破胶剂。通过比较，确定了聚乙烯醇（PVA）和乙烯醋酸乙烯共聚物（EVA）为较好的囊衣材料，通过正交实验研究了两种胶囊破胶剂的制备工艺。结果表明：搅拌速率、温度、衣材与囊芯的质量比、衣材溶液和分散剂的质量分数对胶囊破胶剂性能有较大影响。制备PVA胶囊破胶剂的最佳条件为:温度25℃，搅拌速率270r/min，衣材与囊芯的质量比2:8，分散剂用量为1%；制备EVA胶囊破胶剂的最佳条件为:温度25℃，搅拌速率300r/min，衣材溶液和分散剂的用量为5%和2%。     

纳米磁性液体的分散稳定性分析

从纳米磁性液体中磁性颗粒的沉淀和团聚的角度分析了磁性液体稳定分散的条件，讨论了在外场下磁性颗粒的尺寸对其沉淀的影响，并引入势能的概念定量研究了决定磁性颗粒团聚体形成的3种主要作用力。利用数值计算的方法，讨论了3种相互作用势能以及净势能与磁性颗粒间表面间距和表面活性剂层厚度的关系。结果表明，增大表面活性剂层的厚度是避免磁性颗粒团聚体形成的关键措施。     

一种抑制OCDMA系统色散和非线性效应的方法

色散和非线性效应对光CDMA系统性能会产生严重影响。针对此类问题,该文通过对采用严格最佳(F,k,1)光正交码的单极性光CDMA系统进行理论分析,得到了色散和非线性效应对光CDMA系统性能的影响的量化表达式。数值结果表明:光纤信道的色散和非线性效应会导致系统性能明显下降,因此,色散补偿技术必不可少。不同于传统的色散补偿方案,该文提出采用非零色散位移光纤(NZ-DSF)搭配色散补偿光纤(DCF)的新方案,在进行色散补偿的同时,尽可能弱化非线性效应的影响,从而有效地改善系统性能。