THE POLYMERIZATION OF METHYL METHACRYLATE WITH A NEW TIN-BRIDGED YTTROCENE/Al(i-Bu)_3   总被引：1，自引：0，他引：1  

胡蔚秋  孙俊全  潘智达  吴兆立  许育明 《Journal of Zhejiang University. Science. B》2000,(2)

ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅｔｈｅｐｏｌｙｍｅｒｉｚａｔｉｏｎｏｆｍｅｔｈｙｌｍｅｔｈａｃｒｙｌａｔｅ(ＭＭＡ)ｗｉｔｈｒａｒｅｅａｒｔｈｃａｔａｌｙｓｔｓｗａｓｒｅａｌｉｚｅｄｆｏｒｔｈｅｆｉｒｓｔｔｉｍｅｉｎ1991,ａｓｅｒｉｅｓｏｆｎｅｗｒａｒｅｅａｒｔｈｃａｔａｌｙｓｔｓｙｓｔｅｍｓｓｕｃｈａｓＮｄ(Ｐ204)3/Ａｌ(ｉＢｕ)3,Ｎｄ(Ｐ204)3/Ａｌ(ｉＢｕ)3/ＣＣｌ4,Ｎｄ(Ｏｃｔ)3/Ａｌ(ｉＢｕ)3,Ｌｎ(ａｃａｃ)3/ＢｕＭｇＣｌ,Ｙ(ａｃａｃ)3/Ａｌ(ｉＢｕ)3/ＢｕＬｉ,Ｎｄ(ｎａｐｈ)3/ＢｕＬｉ,ａｎｄＮｄ(Ｏ…  相似文献   

高中英语语篇阅读教学的构想     

东运达  姚志梅  周曙晶 《衡水学院学报》2000,(2)

语篇阅读教学是一种融预期、多种阅读、语言习得、学法指导及能力培养为一体的综合教学方法,它体现了交际教学和素质教育思想,是培养学生阅读能力的有效方法。因此,在高中英语语篇教学中应注意:1、转变教学思想,确立语篇概念。2、将阅读预期作为语篇阅读的必要准备过程。3、进行快速阅读。4、经心详读,记取细节,深化语篇阅读的效果,最后达到语言习得的目的。  相似文献   

Domestic patents and developing countries: arguments for their study and data from Brazil (1980–1995)     

Eduardo da Motta e Albuquerque 《Research Policy》2000,29(9)

This paper presents data from Brazilian Patent Office (Instituto Nacional de Propriedade Industrial, INPI) and compares them with data from the United States Patent Office (USPTO). Developing countries have technological activities that are important locally but not significant at international level (imitation, local learning, adaptation of foreign innovations). These activities might be patentable only at national level. Therefore, the study of domestic patents of developing countries provides a broader picture than USPTO patents. This paper compares 8309 INPI patents with 475 USPTO patents (between 1980 and 1995). Domestic patent data show peculiarities in the Brazilian case, possibly shared with other countries in similar technological level: (a) high share of individual patents; (b) foreign-owned firms with important activities; (c) low firm involvement in R&D activities. Some characteristics are shared with developed countries: (a) domestic firms as the major patentees; (b) according to firm size, there is a U-shaped distribution of patents; (c) evidences of multi-technology large firms; (d) a relatively small share of firms have more than one patent in the whole period. The contrast between USPTO and national patenting statistics shows different rankings according to ownership structure, leading firms, industrial sectors, and international patent classification. These differences highlight sources of international competitiveness and point to weaknesses in Brazilian innovative activities. This paper concludes evaluating the contributions (and weaknesses) of this database for the evaluation of the Brazilian National System of Innovation.  相似文献   

Paragraph-based representation of texts: A complex networks approach     

Henrique F. de Arruda  Vanessa Q. Marinho  Luciano da F. Costa  Diego R. Amancio 《Information processing & management》2019,56(3):479-494

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赛前情绪与运动成绩   总被引：3，自引：1，他引：2  

John M.SilvaⅢ  Charles J.Hardy  张力为  马启伟 《北京体育大学学报》1992,(3)

分析了赛前情绪与运动成绩的关系。研究表明,赛前的自信心程度、梦境、焦虑水平、对操作表现和个人潜力的知觉等因素与运动成绩有关。用《心境状态量表》(POMS)和《8种状态问卷》(8SQ)进行测验,发现了不同水平运动员的不同的情绪模式。由于认知先于情绪,因此,调节情绪应首先从调节认知着手,建立积极的内部条件反射;同时,还应将认知-情绪-行为链式反应各环节作为不可分割的整体。  相似文献   

Legends in Science: from Boom to Bust     

Jaime A. Teixeira da Silva  Judit Dobránszki  Aceil Al-Khatib 《Publishing Research Quarterly》2016,32(4):313-318

In biology and medicine, a scientist’s legend is most commonly determined by their sphere of influence, either on surrounding peers, on clients in the case of medical practitioners, or on the wider scientific public in the case of research scientists. A scientific paper still constitutes the most effective portal through which ideas, knowledge and opinions can be shared among academics and scholars. Thus, legends in science are built upon a scientist’s published literature. Legend was always assumed to be safe in its final form, i.e., a published paper. Yet, a powerful movement of post-publication peer review has begun to identify that not all has been well with the vetting process that led to the publication of a tranche of the scientific literature, and that editorial oversight and weakness has prevailed in a number of cases, leading to retractions and a more critical re-assessment of the literature. One could say that the half-life of a scientific paper has only just begun once it is published. Within this context of science publishing that has given a sense of false security, legends may evolve from boom to bust within the space of weeks or even months. The legendary status of a scientist is therefore no longer safe if there are hidden or undiscovered errors, fraud or misconduct.  相似文献   

Differences in strength and speed demands between 4v4 and 8v8 small-sided football games     

António Natal Campos Rebelo  Pedro Silva  Vincenzo Rago  Daniel Barreira  Peter Krustrup 《Journal of sports sciences》2016,34(24):2246-2254

ABSTRACT

The aims of this study were (i) to characterise the acceleration demands of two different formats of small-sided game (SSG), i.e., 4v4 + goalkeepers (4v4 + GK) and 8v8 + goalkeepers (8v8 + GK); (ii) to analyse the correlation between performance in power-based tests and acceleration-based physical loading during the two different SSG formats and (iii) to analyse the neuromuscular-induced fatigue. Eighteen adult male footballers participated in the study (20.7 ± 1.0 years, 178 ± 5 cm and 71.4 ± 2.1 kg). Baseline measurements were obtained from countermovement jumps, 15 s repeated jumps and 5 and 15 m sprints. A total of 36 min was analysed for each SSG (4v4 + GK: two sets of 3 × 6 min, and 8v8 + GK: 2 × 18 min). Heart rate, blood lactate, perceived exertion and movement pattern (GPS) were analysed. Distances covered by very-high-intensity activities and very-high-speed running were lower in 4v4 + GK than in 8v8 + GK (effect sizes (ES) = ?0.69 ± 0.67 and ?1.04 ± 0.67, respectively; very likely), while accelerations and decelerations were higher in 4v4 + GK than in 8v8 + GK (ES = 1.13–1.52; almost certainly). Blood lactate concentrations were higher (ES = 1.40 ± 0.58; almost certainly) and players perceived themselves to be more tired (ES = 0.80–2.31; almost certainly) after 4v4 + GK than after 8v8 + GK. Sprint ability in 5 and 15 m tests decreased (ES = 0.87 ± 0.58 and 0.89 ± 0.58, respectively; almost certainly) only after 4v4 + GK. This SSG format appeared more demanding in relation to repetitions and fatigue development of muscle power-based actions than 8v8 + GK. It may therefore be logical to use the former type of SSG to target development of power-related football actions.  相似文献   

Physiological responses at the lactate-minimum-intensity with and without prior high-intensity exercise     

Alessandro Moura Zagatto  Johnny Padulo  Adelino Ramos Sanchez da Silva  Paulo de Tarso Guerrero Müller  Willian Eiji Miyagi  Claudio Alexandre Gobatto 《Journal of sports sciences》2016,34(21):2106-2113

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Poor precompetitive sleep habits,nutrients’ deficiencies,inappropriate body composition and athletic performance in elite gymnasts     

M.-R. G. Silva  T. Paiva 《European Journal of Sport Science》2016,16(6):726-735

This study aimed to evaluate body composition, sleep, precompetitive anxiety and dietary intake on the elite female gymnasts’ performance prior to an international competition. Sixty-seven rhythmic gymnasts of high performance level were evaluated in relation to sport and training practice, body composition, sleep duration, daytime sleepiness by the Epworth Sleepiness Scale (ESS), sleep quality by the Pittsburgh Sleep Quality Index (PSQI), precompetitive anxiety by the Sport Competition Anxiety Test form A (SCAT-A) and detailed dietary intake just before an international competition. Most gymnasts (67.2%) suffered from mild daytime sleepiness, 77.6% presented poor sleep quality and 19.4% presented high levels of precompetitive anxiety. The majority of gymnasts reported low energy availability (EA) and low intakes of important vitamins including folate, vitamins D, E and K; and minerals, including calcium, iron, boron and magnesium (p?p?=?.001), sport practice (p?=?.024), number of daily training hours (p?=?.000), number of hours of training/week (p?=?.000), waist circumference (WC) (p?=?.008) and sleep duration (p?=?.005). However, it was negatively correlated with WC/hip circumference (p?=?.000), ESS (p?=?.000), PSQI (p?=?.042), SCAT-A (p?=?.002), protein g/kg (p?=?.028), EA (p?=?.002) and exercise energy expenditure (p?=?.000). High performance gymnasts presented poor sleep habits with consequences upon daytime sleepiness, sleep quality and low energy availability.  相似文献   

Methodological-conceptual problems in the study of chimpanzees’ folk physics: How studies with adult humans can help     

Silva FJ  Page DM  Silva KM 《Learning & behavior》2005,33(1):47-58

In three experiments, we examined humans’ folk physics (i.e., a naturally occurring and spontaneous understanding of the physical world), using variations of problems used to study chimpanzees’ folk physics. Presented with trap-tube problems in two experiments, adult humans showed an unnecessary bias to insert a stick into the end of the tube farthest from the reward to push it out the other end. When presented with trap-table problems with ineffective trapping holes, people unnecessarily avoided the side with the hole. The similarity of humans’ and chimpanzees’ behavior on these tasks highlights methodological and conceptual problems in studies of chimpanzees’ folk physics and suggests alternative explanations for their behavior.  相似文献