Recent advances and challenges in materials for 3D bioprinting

3D bioprinting has been developed as a promising technology in a wide variety of biomedical applications. However, the successful implementation of bioprinting is still heavily restricted by the relatively narrow range of printable and biocompatible materials. Recently, many comprehensive reviews of the main bioprinting methods, commonly used bioprinting materials and the trending bioprinting applications have been carried out. In this review, we focused on the trends in the development of materials for 3D bioprinting. The significance and recent advances of ECM-based materials, multi-material and stimuli-responsive materials for bioprinting were summarized successively. Moreover, the challenges in current studies and future perspectives of materials for 3D bioprinting were discussed.     

基于交通信号灯信息的混合动力汽车节能预测控制方法

针对传统混合动力汽车控制方法不考虑已知道路交通信号灯信息对车辆能量管理影响的问题,提出了基于交通信号灯信息的混合动力汽车节能预测控制智能优化策略。通过建立混合动力汽车系统的简化模型,并采用连续广义最小残量方法求解模型预测控制问题。运用MATLAB/Simulink进行仿真,仿真结果验证了交通信号灯信息模型的有效性,以及所设计的模型预测控制算法大幅度提高混合动力汽车的燃油经济性的能力和实时控制性能。研究结果表明所提出的控制策略可以实现车辆行驶轨迹的优化控制,显著提高了车辆的燃油经济性,并满足系统的实时最优控制要求。     

中国传统服饰美学思想的特征

探讨中国服饰美学思想所涉及的“天人合一”、社会伦理道德以及等级方面的内容．运甩史料考证、逻辑推理及中外比较相结合的论证方法，表明中国传统服饰美学思想是具有鲜明的民族个性特征的，得出中国传统服饰美学思想所涵盖的社会化、自然化和多样化特征．     

Total systems intervention and human inquiry: The search for a common ground

Total Systems Intervention (TSI) is an approach to intervening in problem situations which has much to offer where complex interacting issues need to be addressed by the complementary use of intervention methodologies. That such an approach has much in common with Action Research (AR) has been recognized, with much recent effort being devoted to the relationship between AR and Critical Systems Thinking (CST), the theoretical endeavor underpinning TSI. This paper further develops this line of debate and relates AR or Human Inquiry (HI) more directly to TSI, using an information systems intervention to enhance the study. The outcome is a demonstration of how TSI implicitly uses techniques informed from the field of Action Research, and how a more thorough synthesis of HI with TSI might serve to improve the overall intervention process.     

哪种文化?哪种多元化?——试论"文化多元化"与我国文学发展的关系

在全球化语境和后现代氛围中,中国文学创作、文学批评、文学理论的发展面临巨大的挑战;我们应该反思历史,审时度势、认清目标、坚定信念,为建设“文化多元化”中有影响力的“一元”——中国文化、文学的整体性特色而努力;但作为一种文化策略的“文化多元化”,其涵义暧昧、含混,充满歧义,一定程度上正影响着新世纪中国文学的健康发展。     

广纳文化根系与壮族的文化生态美——壮族文化生态美研究之三

壮族具有一种可称为广纳性文化根系 ,表现为对异质文化的宽容、平等和吸纳和对苗瑶文化、汉族文化的宽容和吸纳 ,形成了壮族许多再生文化、杂糅文化形态 ,也使壮族文化符合生态文化的共生规律。     

国际发展趋势下实验力学的未来作用

考察了分析结构、结构构件以及技术系统中的位移、应变与应力的测量和实验方法在目前和未来的作用。现在,比以往任何时候都更有理由和有更广阔的领域需要用到实验力学方法;许多先进、现代化技术,新型测量设备,测量和赋值过程自动化系统可供使用;以先进的测量技术和计算机技术相结合而形成的各种杂交法已被提出来。利用这些方法,可以优化结构和产品,节约能源和原材料,提高产品质量,增强结构、技术系统的可靠、安全性,控制生产过程以及监督操作系统的安全性;利用这些方法,能够并且应当使技术系统可能发生的危险以及对环境的毁损降至最低程度。     

玉米两个自交系及其杂交F_1染色体G-带带型的比较

对玉米两个自交系京7和华5及其杂交F_1的染色体G-带带型进行了比较研究。结果表明,两自交系的G-带中A型带之间的相似点很多,有的完全一致;而B型带在带的数目和分布位置上有差异。杂交F_1的G-带带型具有杂合性,B型带的杂合性尤为明显。文中讨论了G-带、C-带和N-带并存等问题。     

The genetic diversity of cen-tral and peripheral popula-tions of ratlike hamster(Cricetulus triton)

The impact of habitat fragmentation and isolation on the genetic diversity of populations has attracted much attention in studies of meta-population and conservation biology. In this work, using the randomly amplified polymorphic DNA (RAPD) technique, we studied the genetic diversity of central, peripheral and peninsular populations of ratlike hamster, which were collected in five locations of the North China Plain and its surrounding areas, in 1999. The study revealed that, ⅰ) the genetic diversity of central population of Raoyang County＞the sub-central populations of Gu'an County and Taikang County＞the peripheral population of Shunyi District＞the peninsular population of Mentougou District; ⅱ) the genetic diversities of the five populations were positively correlated to the nearest distances to the peripheral line of population distribution; ⅲ) there were significant differences of gene frequencies of some RAPD fragments among the five populations. More RAPD fragments disappeared in peripheral populations than in central or sub-central populations. The frequencies of two RAPD fragments were correlated to the latitude. This study clearly indicated that the variation of the genetic diversities of the five populations was caused by edge effect and frag- mentation through the enhanced inbreeding and genetic drift, and thus supported the view that habitat fragmentation and related edge effect reduce the population genetic diversity.     

解常微分方程初值问题的一类混合单步法

本文给出一类解常微初值问题的混合单步法。与现有的线性单步多导法相比，利用相同阶的导数信息本文的方法却能获得更高的阶，并且其中相当一部分具有Ｌ－稳定性Ａ－稳定性。本文首先给出方法的一般构造方法，然后给一些实用的特例，最近对方法的实际使用也略作了讨论。