中国绿色经济发展展望--基于系统动力学模型的情景分析

绿色经济已经在世界范围内引起各国政府的重视。本研究构建的中国可持续发展模型,选择农业、森林、绿色建筑、可再生能源和核能、城市生活垃圾、城市交通、水泥产业7个行业从绿色经济的角度进行界定和模拟,通过情景仿真分析,分析发展绿色经济对中国经济、社会、环境系统的潜在影响。模拟结果显示,走绿色发展道路,中国可以实现更有质量的经济增长。同时,需要加强部门间的统筹协调,从整体层面制定绿色经济相关规划。     

协同动力视角下新能源产业成长机制研究

将新能源产业看作一个复杂的系统,运用系统动力学的方法理论对其进行建模分析。新能源产业成长受内在要素和外在要素共同影响,把市场需求、技术进步、政府推动看作是新能源产业发展的外部要素,企业竞争与协作看作是内部要素。通过绘制系统因果回路图及流图建立新能源产业成长动力模型。最后,运用协同学理论分析该动力机制模型,并为我国新能源产业发展提出针对性政策建议。     

考虑土地资源占用的港口与城市经济互动发展系统仿真——以深圳市为例

在分析港口与城市经济互动发展系统结构和特征的基础上,构建了基于系统动力学(SD)的因果关系图,选取城市GDP、港口通过能力、港区占地面积、港口深水岸线长度作为状态变量,构建系统流图和系统动力学方程。以深圳市为例进行实证分析,通过对仿真模型结构和行为的检验,验证了模型的有效性。选取港口投资政策因子、岸线消耗系数、港区土地占用系数、港外土地占用系数以及表示港口业对航运服务业和港口物流业促进程度的乘数作为控制变量进行仿真,分析这些因素对港口与城市经济互动发展系统的影响。仿真结果表明,为实现深圳港口和城市2020年发展目标,需要适当的增加港口建设投资,但要避免码头重复建设带来的土地资源大量占用问题;集约利用港口土地资源,提高土地资源的利用效率;同时提升港口的物流和航运服务功能,以实现港口的转型升级。     

我国数字化专业科技期刊集群的形成与发展

探讨我国数字化专业科技期刊集群这一新兴出版模式的形成与发展.基于集群理论界定我国数字化专业科技期刊集群的概念,梳理我国数字化专业科技期刊集群的现实格局.从基本因素和扩展因素2个层面阐释其集聚动因,从组织结构、形成动力和群内关系上归纳其集聚模式.对其未来发展方向做了展望.     

Effects of changing speed on knee and ankle joint load during walking and running

Joint moments can be used as an indicator of joint loading and have potential application for sports performance and injury prevention. The effects of changing walking and running speeds on joint moments for the different planes of motion still are debatable. Here, we compared knee and ankle moments during walking and running at different speeds. Data were collected from 11 recreational male runners to determine knee and ankle joint moments during different conditions. Conditions include walking at a comfortable speed (self-selected pacing), fast walking (fastest speed possible), slow running (speed corresponding to 30% slower than running) and running (at 4 m · s^?1 ± 10%). A different joint moment pattern was observed between walking and running. We observed a general increase in joint load for sagittal and frontal planes as speed increased, while the effects of speed were not clear in the transverse plane moments. Although differences tend to be more pronounced when gait changed from walking to running, the peak moments, in general, increased when speed increased from comfortable walking to fast walking and from slow running to running mainly in the sagittal and frontal planes. Knee flexion moment was higher in walking than in running due to larger knee extension. Results suggest caution when recommending walking over running in an attempt to reduce knee joint loading. The different effects of speed increments during walking and running should be considered with regard to the prevention of injuries and for rehabilitation purposes.     

Intentional thought dynamics during exercise performed until volitional exhaustion

Using a non-linear approach, intentional dynamics of thoughts were examined during constant cycling performed until volitional exhaustion. Participants (n = 12) completed two sessions at 80% W_max. Their (1) intrinsic thought dynamics (i.e., no-imposed thoughts condition) and (2) intentional thought dynamics (i.e., imposed task-unrelated thoughts condition; TUT) were recorded and then classified into four categories: internal and external TUT (TUT-I, TUT-E) and external and internal task-related thoughts (TRT-E, TRT-I). The probability estimates for maintaining each thought category stable, the rate of switching from one category to another, and the entropy dynamics along the testing procedure were assessed and compared through time phase. Friedman ANOVA tests revealed a significant effect of effort increase on thought contents only in the imposed TUT test. While TUT-I probabilities decreased significantly (P < .001) as effort increased, TRT-I probabilities increased (P < .05). Moreover, the entropy to the entire thought dynamics increased at the outset of task performance and decreased upon approaching volitional exhaustion (P < .001). As time spent in constant effort increased, and volitional exhaustion approached, task relatedness (TUT, TRT), direction (internal, external), and entropy of thought contents changed unintentionally providing further evidence for a nonlinear dynamics of attention focus.     

分子动力学方法研究环氧树脂力学性能参数

采用分子动力学方法,计算交联度92%的环氧树脂的力学性能参数,并比较不同温度下,环氧树脂力学性能参数的改变。研究结果表明,分子动力学模拟结果与试验结果相吻合。模拟结果显示,随着温度升高,交联环氧树脂的弹性模量、剪切模量和体积模量等性能下降,温度高于玻璃温度之后,环氧树脂力学性能下降显著。     

全球化时代OECD国家高等教育扩张的社会动力研究——教育需求的视角

20世纪90年代以来,随着全球化进程的加速,OECD国家失业率居高不下、低质量就业日渐增多、收入分配调节弱化。在此背景下,高等教育对个体的重要性不断增强,接受高等教育可能预示着更多的就业机会、更高的就业质量、更高的收入水平以及更高的生活质量,这导致了个体高等教育需求的强化。社会上日益增长的教育需求成为驱动高等教育规模扩张的基本动力。     

Gaming personality and game dynamics in online discussion instructions

Gamification is the use of game mechanics to drive game-like engagements and actions. It applies game mechanics, dynamics and frameworks to promote desired learning behaviours. Positive and effective gamification could enhance learning and engage learners in more social and context-rich decision-making for problem-solving in learning tasks. Effective gamification design should understand the game personalities of learners, social engagement styles, and intrinsic- and extrinsic-motivated user styles initially and evaluate and select appropriate game mechanics, game dynamics, to create ideal gamification instructions. The research question this study investigated is: How will four types of gaming personalities (i.e. Explorer, Socialiser, Killer and Achiever) predict the level of game dynamics in online discussion environments? This study concluded that examining how gaming personalities relate to game dynamics in a gamified online discussion instruction is not sufficient to design effective gamification. It suggests future studies in game instructions should focus on the relationships between game dynamics, gamification contexts, gaming personalities or preferences, dynamic gaming engagement styles, etc.