电子书用户使用意愿影响模型构建与实证     

杨方铭  张志强 《图书情报工作》2020,64(9):85-94

[目的/意义] 探究用户使用电子书意愿的影响因素，以有助于电子书产业走出缓慢的发展困境。[方法/过程] 以UTAUT2、使用满足理论为基础，从需求满足和外部情景因素两个层面构建影响因素模型，并将需求满足细化为内容需求、社交互动需求和休闲娱乐需求3个测量变量。采用问卷调查方法收集有效样本1 013份，使用AMOS21软件对模型进行验证。[结果/结论] 研究发现，需求满足、阅读习惯、价格价值、社会影响对使用意愿有正向影响作用，而激励措施对使用意愿有负向影响作用，努力期望对使用意愿的影响不显著，并依据研究结果提出促进电子书产业发展的建议。  相似文献   

汇川H2U系列PLC之间RS-485通信的实现     

尚丽  叶国平 《苏州市职业大学学报》2020,(2):15-21

主要研究了汇川公司H2U可编程控制器(PLC)的通信技术,实现了两个H2U系列PLC之间基于RS-485的通信,并详细介绍了PLC之间通信的硬件连接方式、通信串口参数配置、触摸屏画面的设计以及程序实现。所讨论的方法已在采用H2U PLC及辅助设备组建的"运动控制系统"课程的教学实验平台上进行了验证,可以拓展应用于多台H2U PLC之间以及其他设备与H2U PLC之间的RS-485通信实现,对工程应用具有一定的借鉴意义。  相似文献   

一种基于模糊语言TOPSIS的应急决策方法     

李海明  虞钢  田崇鑫  尚国彬 《中国科学院大学学报》2020,37(6):814-819

在应急决策过程中，决策信息通常具有犹豫性、模糊性和非对称性，且决策者呈现出直观、快速的语言决策偏好。提出一种基于模糊语言TOPSIS的应急决策方法，使用犹豫模糊语言术语集和二元语义表达式对高度不确定环境下的语言进行处理，提高对犹豫模糊语言信息的提取能力，生成易于理解的语言评估结果，从而辅助决策者进行快速、准确的决策判断。案例证实该方法的可行性与有效性，为解决应急决策问题提供了一种新方法。  相似文献   

Where are we now? A review of research on the history of women's soccer in Ireland     

Helena Byrne 《Sport in History》2019,39(2):166-186

ABSTRACT

It is a common fact that women's sport and leisure history, especially in male dominated spheres, and more specifically football, have been ignored by many academics. However, in recent years there have been major developments in digital technology that have changed the nature of the type of research that can be done. Access to tools to facilitate field research are relatively cheap and with the high volume of digitisation projects that have taken place over the last few years as well as the increasing number of born digital resources that have been published, there are new opportunities. In relation to women's soccer in Ireland, this paper asks the question – where are we now? The argument will review the current literature on this subject and outline potential approaches for future research.  相似文献   

不同负荷运动训练对大鼠骨骼肌线粒体三羧酸循环的影响及其机制研究     

李洁  杨静  赵丽丽 《武汉体育学院学报》2019,53(5):88-94

目的：探讨不同负荷运动训练对大鼠骨骼肌线粒体三羧酸循环的影响及其机制。方法：将雄性Wistar大鼠50只随机均分为5组：安静对照组（C）、低负荷运动训练组（LT）、中等负荷运动训练组（MT）、高负荷运动训练组（HT）和极高负荷运动训练组（ST），每组10只。各运动组分别进行6周的跑台运动训练。训练方案结束后，取腓肠肌样本，提取线粒体，测定线粒体柠檬酸合成酶（CS）、异柠檬酸脱氢酶（ICD）和α-酮戊二酸脱氢酶（α-KGDHC）活性；线粒体Ga²⁺含量、胞浆NADH、NAD⁺、ATP和ADP含量，以及ICD mRNA转录水平。结果：（1）不同负荷运动训练组线粒体CS、ICD和α-KGDHC的活性均显著高于安静对照组（P < 0.01），且CS和ICD活性由高到低顺序均为：MT组 > HT组 > ST组 > LT组 > C组，α-KGDHC活性由高到低顺序为：HT组 > MT组 > ST组 > LT组 > C组。（2）不同负荷运动训练组线粒体Ca²⁺ 含量均显著高于安静对照组（P < 0.01），其含量由高到低顺序为：MT组 > HT组 > ST组 > LT组 > C组；胞浆NADH/NAD⁺和ATP/ADP的比值均显著低于安静对照组（P < 0.01），其比值由低到高顺序为：MT组 < ST组 < HT组 < LT组 < C组。（3）不同负荷运动训练组ICD mRNA转录水平均高于安静对照组（P < 0.01），其水平由高到低顺序为： MT组 > HT组 > ST组 > LT组 > C组。结论：低负荷、中等负荷、高负荷及极高负荷运动训练均可提高大鼠骨骼肌线粒体三羧酸循环功能，且中等负荷运动训练效果最佳。其机制与胞浆NADH/NAD⁺和ATP/ADP比值、线粒体摄钙能力及限速酶基因的表达有关。  相似文献   

平行/重合D膜超势，Ooguri-Vafa不变量与类型II弦理论/F理论对偶     

蒋笑添  杨富中 《中国科学院大学学报》2019,36(5):590-597

利用类型Ⅱ弦理论/F理论对偶，第一次在平行和重合相区计算一个具体的双D膜系统的超势，并提取Ooguri-Vafa不变量。平行D膜相与重合D膜相间的相变也对应着D膜世界叶上规范理论规范对称性的提升U（1）×…×U（1）→U（n）。计算显示这两个相区的超势截然不同，并给出不同的Ooguri-Vafa不变量。这意味着相变的发生导致两个相区能谱结构的差异。  相似文献   

Game-Based Learning in Virtual Worlds: A Multiuser Online Game for Medical Undergraduate Radiology Education within Second Life     

Rocio Lorenzo-Alvarez  Teodoro Rudolphi-Solero  Miguel J. Ruiz-Gomez  Francisco Sendra-Portero 《Anatomical sciences education》2020,13(5):602-617

Game-based learning can have a positive impact on medical education, and virtual worlds have great potential for supporting immersive online games. It is necessary to reinforce current medical students' knowledge about radiological anatomy and radiological signs. To meet this need, the objectives of this study were: to design a competition-based game in the virtual world, Second Life and to analyze the students' perceptions of Second Life and the game, as well as to analyze the medium-term retention of knowledge and the potential impact on the final grades. Ninety out of 197 (45.6%) third-year medical students voluntarily participated in an online game based on self-guided presentations and multiple-choice tests over six 6-day stages. Participants and non-participants were invited to perform an evaluation questionnaire about the experience and a post-exposure knowledge test. Participants rated the experience with mean scores equal to or higher than 8.1 on a 10-point scale, highlighting the professor (9.5 ± 1.1; mean ± SD) and the virtual environment (8.9 ± 1.1). Participants had better results in the post-exposure test than non-participants (59.0 ± 13.5 versus 45.3 ± 11.5; P < 0.001) and a lower percentage of answers left blank (6.7 ± 8.4 versus 13.1 ± 12.9; P = 0.014). Competitive game-based learning within Second Life is an effective and well-accepted means of teaching core radiological anatomy and radiological signs content to medical students. The higher medium-term outcomes obtained by participants may indicate effective learning with the game. Additionally, valuable positive perceptions about the game, the educational contents, and the potential benefit for their education were discovered among non-participants.  相似文献   

Committee standards battles in the era of convergence: Implications for smart systems     

《International Journal of Information Management》2021

By now, there have been many standards battles fought within the same industry or by multiple industries in the market-based standardization. In these battles, incompatible standards compete to win market dominance. While there is some research on standards battles found within a single committee, competitions in the committee-based standardization between standards from different committees or SDOs are underexplored. This paper categorizes the types of standards battles by the mode of standardization and the heterogeneity of actors. A new type referred to as ‘committee standards battles for converging systems’ is introduced and the dynamics of such battles is explored with two cases. The battle between the electric vehicle charging and the smart meter communication standard and the battle between two different vehicle-to-everything (V2X) communication standards are analyzed. The failure in achieving compatibility between different committee standards on the same frequency bands results in communication interference that adversely affects the operation of smart systems. Social incompatibilities between actors and alliances from a mix of industries with vested interests towards a particular standard complicate the battling scene. The findings provide implications in terms of heterogeneity, actors, and government role in standards battles.  相似文献   

Press Credentials and Hybrid Boundary Zones: The Case of WorldNetDaily and the Standing Committee of Correspondents     

Jordan M. Foley 《Journalism Practice》2020,14(8):933-953

ABSTRACT

Press credentialing practices are a vital, yet understudied site of scholarly research on journalistic norms and practices. Press credentialing not only structures internal professional hierarchies, but they also signify the boundaries of the journalistic field itself. This paper explores the legal and theoretical implications of press credentialing to cover the United States Congress, drawing on the concepts of boundary work and journalistic authority to demonstrate the material impact of the space between fields on professional legitimation in journalism. Using WorldNetDaily (WND) as a case study, I argue that the Standing Committee of Correspondents (SCC) occupies a hybrid boundary zone between the journalistic and political fields, generating a unique tension in First Amendment jurisprudence that places journalists in a paradoxical role as both the professional embodiments of free speech and its constitutional steward. The resulting jurisdictional conflict between the SCC and WND extends the relational model of journalistic authority by articulating how journalist-state relations can fundamentally augment the process of legitimation at its fuzzy boundaries. The relevance and implications for press credentialing practices in the digital age are discussed.  相似文献   

Combined effects of exposure to hypoxia and cool on walking economy and muscle oxygenation profiles at tibialis anterior     

Masahiro Horiuchi  Yoko Handa-Kirihara  Daijiro Abe  Yoshiyuki Fukuoka 《Journal of sports sciences》2019,37(14):1638-1647

We investigated combined effects of ambient temperature (23°C or 13°C) and fraction of inspired oxygen (21%O₂ or 13%O₂) on energy cost of walking (C_w: J·kg^?1·km^?1) and economical speed (ES). Eighteen healthy young adults (11 males, seven females) walked at seven speeds from 0.67 to 1.67 m s^?1 (four min per stage). Environmental conditions were set; thermoneutral (N: 23°C) with normoxia (N: 21%O₂) = NN; 23°C (N) with hypoxia (H: 13%O₂) = NH; cool (C: 13°C) with 21%O₂ (N) = CN, and 13°C (C) with 13%O₂ (H) = CH. Muscle deoxygenation (HHb) and tissue O₂ saturation (StO₂) were measured at tibialis anterior. We found a significantly slower ES in NH (1.289 ± 0.091 m s^?1) and CH (1.275 ± 0.099 m s^?1) than in NN (1.334 ± 0.112 m s^?1) and CN (1.332 ± 0.104 m s^?1). Changes in HHb and StO₂ were related to the ES. These results suggested that the combined effects (exposure to hypoxia and cool) is nearly equal to exposure to hypoxia and cool individually. Specifically, acute moderate hypoxia slowed the ES by approx. 4%, but acute cool environment did not affect the ES. Further, HHb and StO₂ may partly account for an individual ES.  相似文献