BD-2/GPS组合导航系统选星算法及定位分析

为解决组合导航系统定位精度与快速定位之间的矛盾,提出一种新的选星算法.该方法将可见卫星仰角与遗传算法相结合,以几何精度因子(GDOP)计算模型作为遗传算法中判断解优劣的适应度函数,从而达到快速定位的效果.将应用该方法所得的GDOP和算法运行时间与应用最佳GDOP算法计算所得的相应结果进行对比,发现采用该方法得到的GDOP接近最优值,而且选星算法计算时间减少.实验数据分析证明该方法在实时性和可行性方面的优越性.     

运动训练对大鼠主动脉一氧化氮合酶及细胞凋亡的影响

目的:探讨不同强度训练对大鼠主动脉一氧化氮合酶(NOS)及细胞凋亡的影响。方法:采用跑台训练方式,建立大鼠有氧运动和疲劳运动模型,运用免疫组织化学SABC法研究不同运动强度对大鼠主动脉神经型一氧化氮合酶(neuronal nitric oxide synthase,nNOS)、诱导型一氧化氮合酶(in-duced nitric oxide synthase,iNOS)、内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)和细胞凋亡蛋白(Bcl-2/Bax)表达的影响。结果:有氧训练组与对照组比较,主动脉NOS 3个亚型及Bcl-2,Bax表达差异显著(P<0.05);疲劳训练组与对照组和有氧训练组比较,主动脉iNOS、eNOS及Bcl-2,Bax表达差异显著(P<0.05),nNOS虽有增加但差异不显著。结论:运动可引起大鼠主动脉NOS 3个亚型及Bcl-2,Bax表达变化,且与运动强度关系密切。有氧训练可使主动脉NOS适度表达且抑制细胞凋亡,疲劳训练会导致大鼠主动脉iNOS过量表达,细胞发生凋亡现象。因此认为,运动训练引起NOS亚型表达变化与运动诱导的主动脉细胞凋亡关系密切。     

PBL模式在生物技术专业细胞生物学教学中的应用

细胞生物学是生物技术专业的基础课,发展迅速,且与其他生命科学交叉渗透,难于理解。为了激发学生的学习热情,提高学生分析问题和解决问题的能力,同时提高课堂教学质量,在细胞生物学的改革实践中,在传统教学的基础上,引入了PBL模式教学。实践证明PBL模式教学取得了较为满意的效果,同时也存在一些不足。     

Principal component analysis and cluster analysis based orbit optimization for earth observation satellites

This paper proposes a design optimization method for the multi-objective orbit design of earth observation satellites, for which the optimality of orbit performance indices with different units, such as: total coverage time, the frequency of coverage, average time per coverage and maximum coverage gap, etc. is required simultaneously. By introducing index normalization method to convert performance indices into dimensionless variables within the range of [0, 1], a design optimization method based on the principal component analysis and cluster analysis is proposed, which consists of index normalization method, principal component analysis, multiple-level cluster analysis and weighted evaluation method. The results of orbit optimization for earth observation satellites show that the optimal orbit can be obtained by using the proposed method. The principal component analysis can reduce the total number of indices with a non-independent relationship to save computing time. Similarly, the multiple-level cluster analysis with parallel computing could save computing time.     

骨骼肌卫星细胞的活性及影响因素

骨骼肌卫星细胞通过激活、基因表达、增殖分化途径主要形成成肌干细胞,维持、修复骨骼肌结构和功能.卫星细胞的活性受多种因素影响.主要从卫星细胞的激活、基因表达、增殖分化等活性和影响卫星细胞活性的各种相关因素两大方面对骨骼肌卫星细胞进行综述.     

太阳电池发电系统的最佳功率流控制

本文提出一种实现太阳电池输出最大功率的跟踪控制方法,给出实验结果,证实这一控制方法的可行性和有效性。文中还讨论了太阳电池发电系统最佳功率流控制的实现方法以及补偿无功功率和谐波失真等问题.     

炙甘草汤对豚鼠心室肌细胞的电生理影响

目的：研究炙甘草汤对豚鼠心室肌细胞电生理影响。方法：应用常规的玻璃微电极细胞内记录技术，观察炙甘草汤对豚鼠心室肌细胞的动作电位0相幅值（APA）。动作电位时程（APD），50％复极化时间（APD50），90％复极化时间（APD90）的影响。结果：（1）用20mg／ml的炙甘草汤灌流后与正常对照组相比细胞电生理变化不明显；（2）用40mg／ml的炙甘草汤灌流后与正常对照组相比动作电位时程（APD）缩短（P〈0．05），90％复极化时间（APD90）下降（P〈0．05）；（3）用80mg／ml的炙甘草汤灌流后与正常对照组相比动作电位时程（APD）明显缩短（P〈0.01），50％复极化时间（APD50）、90％复极化时间（APD90）下降（P〈0．05）。结论：炙甘草汤能缩短豚鼠心室肌细胞动作电位时程及50％、90％复极化时间。     

Programmed cell death features in apple suspension cells under low oxygen culture

INTRODUCTION A number of abiotic stresses have been shown to induce programmed cell death (PCD) responses in plant cells. High temperatures (e.g. 55 篊) induce nuclear condensation and DNA fragmentation in cultured carrot, cucumber and Arabidopsis cells (McCabe et al., 1997; McCabe and Leaver, 2000), and also mitochondrial cytochrome c release in cucumber cotyledons (Balk et al., 1999). The PCD pathway also appears to be activated by ozone. Ozone induces an oxidative burst with acc…     

Redesigning chat forum for critical thinking in a problem-based learning environment

Support is needed to promote problem-based learning (PBL) and to enhance critical thinking skills in discussion-based Internet forums. By advancing the capabilities of chat room and forum software, problem-based discussions for learning can be supported further in online learning environments. In this paper, the authors report on MALESAbrain, an intelligent learning tool. The model is built on the notions of threshold and knowledge weight from the discipline of machine learning. The model encourages learners to judge or critically evaluate the solutions posted by others before exploring further knowledge content. The system then sums up the judgment scores as its knowledge weight to pass the thresholds setup for ranking/arranging the learning issues. This constraint design, therefore, becomes a mechanism for critical thinking in a problem-based learning activity. MALESAbrain as a model helps transform the forum and chat room into rich learning discussion environments.     

细胞分子生物学实验教学中显微数码互动系统的应用

在高校的实验课堂中,通过显微数码互动系统的应用,把光学显微镜、计算机及网络技术进行了结合,并在课堂中充分利用,实现了师生之间的直观交流、充分互动以及资源共享,能明显提高教学质量和效率。