乳化炸药化学敏化温度与密度

乳化炸药化学敏化过程是影响产品质量的最关键工艺之一,其中敏化温度和敏化后最终密度是最重要的影响因素。试论述不同敏化温度和敏化密度对炸药稳定性与产品性能的影响。     

移动图书馆情景感知信息推荐服务用户接受行为研究

[目的/意义]基于多理论假设,为移动图书馆平台提供基于情景感知的信息推荐服务提供理论和实证依据,以丰富移动图书馆个性化服务的内容。[方法/过程]结合技术接受行为理论、创新扩散理论和感知风险理论,构建基于情景感知的信息推荐服务用户接受行为影响因素模型,并运用逻辑回归方法进行实证研究。[结果/结论]情景感知信息推荐服务作为移动图书馆信息服务的新方式,有着个性化的显著优势。同时,技术和设备的兼容为移动图书馆情景感知信息推荐服务提供了外部动力和重要保障。     

现代思想政治教育发展动因探讨

在现代社会,思想政治教育不仅没有退出历史舞台,反而得到更为丰富的发展,为我国经济工作、政治工作等社会主义各项事业提供着强大的理论支撑和智力支持。究其原因,思想政治教育的科学性是其理论动因,思想政治教育的政治性是其外部动因,思想政治教育的价值性是其内部动因,思想政治教育的草根性是其社会动因。     

An efficient method of addressing ectopic beats: new insight into data preprocessing of heart rate variability analysis

Heart rate variability (HRV) analysis is affected by ectopic beats. An efficient method was proposed to deal with the ectopic beats. The method was based on trend correlation of the heart timing signal. Predictor of R-R interval (RRI) value at ectopic beat time was constructed by the weight calculation and the slope estimation of preceding normal RRI. The type of ectopic beat was detected and replaced by the predictor of RRI. The performance of the simulated signal after ectopic correction was tested by the standard value using power spectrum density (PSD) estimation, whereas the results of clinical data with ectopic beats were compared with the adjacent ectopic-free data. The result showed the frequency indexes after ectopy corrected had less error than other methods with the test of simulated signal and clinical data. It indicated our method could improve the PSD estimation in HRV analysis. The method had advantages of high accuracy and real time properties to recover the sinus node modulation.     

A multiple-dose pharmacokinetics of polyethylene glycol recombinant human interleukin-6 (PEG-rhIL-6) in rats

Radiation therapy has been widely applied in cancer treatment. However, it often causes thrombocytopenia (deficiency of white blood cells) as an adverse effect. Recombinant human interleukin-6 (rhIL-6) has been found to be a very effective way against this thrombocytopenia, but IL-6 has low stability in blood, which reduces its efficacy. To increases the stability and half-life of rhIL-6, it was modified by polyethylene glycol (PEG). The pharmacokinetics and the tissue distribution of PEG-rhIL-6 labeled with ¹²⁵I were examined after subcutaneous injection in rats. The pharmacokinetic pattern of PEG-rhIL-6 was defined with linear-kinetics, and we fitted a one-compartment model with half-lives of 10.44–11.37 h (absorption, t _{1/2K a}) and 19.77–21.53 h (elimination, t _1/2Ke), and peak concentrations at 20.51–21.96 h (t _peak) in rats. Half-lives and t _peak of PEG-rhIL-6 were longer than those of rhIL-6 previously reported. In the present study, for deposition of PEG-rhIL-6 in rats, the tissue distribution examination showed that blood was the major organ involved, rather than liver. However, as to the elimination of PEG-rhIL-6, the major organ was the kidney. The excretion fraction of the injection dose recovered from urine was 23.32% at 192 h after subcutaneous administration. Less than 6% of PEG-rhIL-6 was eliminated via the feces at 192 h. These results indicate that PEG-rhIL-6 is a good candidate drug formulation for patients with cancer.     

Effect of epidermal growth factor on follicle-stimulating hormone-induced proliferation of granulosa cells from chicken prehierarchical follicles

The development of ovarian follicular cells is controlled by multiple circulating and local hormones and factors, including follicle-stimulating hormone (FSH) and epidermal growth factor (EGF). In this study, the stage-specific effect of EGF on FSH-induced proliferation of granulosa cells was evaluated in the ovarian follicles of egg-laying chickens. Results showed that EGF and its receptor (EGFR) mRNAs displayed a high expression in granulosa cells from the prehierarchical follicles, including the large white follicle (LWF) and small yellow follicle (SYF), and thereafter the expression decreased markedly to the stage of the largest preovulatory follicle. SYF represents a turning point of EGF/EGFR mRNA expression during follicle selection. Subsequently the granulosa cells from SYF were cultured to reveal the mediation of EGF in FSH action. Cell proliferation was remarkably increased by treatment with either EGF or FSH (0.1–100 ng/ml). This result was confirmed by elevated proliferating cell nuclear antigen (PCNA) expression and decreased cell apoptosis. Furthermore, EGF-induced cell proliferation was accompanied by increased mRNA expressions of EGFR, FSH receptor, and the cell cycle-regulating genes (cyclins D1 and E1, cyclin-dependent kinases 2 and 6) as well as decreased expression of luteinizing hormone receptor mRNA. However, the EGF or FSH-elicited effect was reversed by simultaneous treatment with an EGFR inhibitor AG1478. In conclusion, EGF and EGFR expressions manifested stage-specific changes during follicular development and EGF mediated FSH-induced cell proliferation and retarded cell differentiation in the prehierarchical follicles. These expressions thus stimulated follicular growth before selection in the egg-laying chicken.     

Lumped parameter model for resonant frequency estimation of a thermoacoustic engine with gas-liquid coupling oscillation

Gas-liquid coupling oscillation is a novel approach to reducing the resonant frequency and to elevating the pressure amplitude of a thermoacoustic engine. If a thermoacoustic engine is used to drive low-frequency pulse tube refrigerators, the frequency matching between the thermoacoustic engine and the refrigerator plays an important role. Based on an acoustic-electric analogy, a lumped parameter model is proposed to estimate the resonant frequency of a standing-wave thermoacoustic engine with gas-liquid coupling oscillation. Furthermore, a simplified lumped parameter model is also developed to reduce the computation complexity. The resonant frequency dependence on the mean pressure, the gas space volume, and the water column length is computed and analyzed. The impact of different working gases on the resonant frequency is also discussed. The effectiveness of the models is validated by comparing the computed results with the experimental data of the gas-liquid coupling oscillation system. An increase in the mean working pressure can lead to a rise in the resonant frequency, and a lower resonant frequency can be achieved by elongating the liquid column. In comparison with nitrogen and argon, carbon dioxide can realize a lower frequency due to a smaller specific heat ratio.     

Dynamic responses of cable-stayed bridges to vehicular loading including the effects of the local vibration of cables

Stay cables, the primary load carrying components of cable-stayed bridges (CSBs), are characterised by high flexibility which increases with the span of the bridge. This makes stay cables vulnerable to local vibrations which may have significant effects on the dynamic responses of long-span CSBs. Hence, it is essential to account for these effects in the assessment of the dynamics CSBs. In this paper, the dynamic responses of CSBs under vehicular loads are studied using the finite element method (FEM), while the local vibration of stay cables is analyzed using the substructure method. A case study of a cable-stayed steel bridge with a center span of 448 m demonstrates that stay cables undergo large displacements in the primary mode of the whole bridge although, in general, a cable’s local vibrations are not obvious. The road surface roughness has significant effects on the interaction force between the deck and vehicle but little effect on the global response of the bridge. Load impact factors of the main girder and tower are small, and the impact factors of the tension of cables are larger than those of the displacements of girders and towers.     

当代都市题材油画的平民意识

随着社会的不断发展进步,平民大众的历史主体地位日益被肯定。在中国当代都市题材油画中,同样反映了一种平民化的价值倾向。如画家刘小东描绘了多种职业,各种年龄段的都市"小人物"形象,忻东旺则把视线落在生活在都市社会底层的农民工身上,关注视线向普通大众的转移构成了中国当代油画的一个亮点。     

EJS建模软件在中学物理探究式教学中的应用研究

EJS是一种基于现代教学思想的新型教学软件,其特点是创作过程简单、自动生成代码,界面友好,使学生可以利用特定的可视化模型来学习具体、抽象的概念,并在自己探究、理解、证明的基础上记忆,最终达到灵活运用、解决问题的目的。该文以中学物理教学为例介绍该软件的使用方法及基于EJS支持下的探究式教学的设计和学生开展探究的关键点,并进行实证了分析和反思。基于EJS支持的物理探究式教学可以增强学生对知识的理解,培养学生的问题解决能力,提高学生对相关知识的学习成绩。