Approach for electrodynamic force for compensation in low voltage circuit breaker WP 630-1.2 type     

LU Na XU L.J Miedzifiski B 《浙江大学学报(A卷英文版)》2007,8(3):393-396

Undesirable repulsive force between contact members due to both a current path shrink near a real contact area and/or so-called pinch effect is particularly onerous for power switch applications, and results in either contact floating or bouncing which are associated with an electric arc following contact welding. This problem is of great importance for any circuit breaker especially for compact low voltage vacuum circuit breakers. To avoid contact floating at closure and during any inrush current under short circuit conditions, the electrodynamic repulsive force can be employed successfully if we use a special compensation system flexibly combined with the contact itself. However to select and design the compensation system properly, its efficiency has to be known. This paper presents an approach to obtain the electrodynamic force value depending on different shaped (rectangular, square, circle and arch) copper plates used in the compensator by using ANSYS for current values 40 kA RMS. Curve-fitting was done according to the calculating results, the optimization designing of compensation unit is based on them.  相似文献   

Values Attributed to Marriage by Persons with Physical Disabilities     

Krystyna Błeszyńska 《International Journal of Disability, Development & Education》1995,42(3):203-210

Within the so‐called normal society one can observe again and again symptoms of reluctance to being closely associated with people with physical disabilities. The general opinion is that this group of people is characterised by specific psychological and physical functioning and they are thought to have distinct needs and expectations as regards family life. To verify and confirm the above, comparative research was undertaken to find out how young able‐bodied, blind and persons using wheelchairs evaluate marriage. The subject of the research was the importance ascribed to the hierarchy of values related to marriage and family, and the types of needs satisfied through these institutions of social life. The participants were asked to evaluate such phenomena as love, sexual life and parenthood as well as expressing their attitude and opinion on conjugal infidelity. The results obtained do not indicate any significant differences in attitudes and views presented between the groups under consideration. All valued marriage and family life very highly and had similar expectations, however, not all will be able to fulfil their needs and aspirations in these areas. It will be quite complicated, especially so for those who are disabled. All possible failures are caused by, first of all, negative attitudes of the society towards erotic activities of people with disabilities.  相似文献   

Oculomotor dynamics in skilled soccer players: The effects of sport expertise and strenuous physical effort     

Teresa Zwierko  Wojciech Jedziniak  Beata Florkiewicz  Miłosz Stępiński  Rafał Buryta  Dorota Kostrzewa-Nowak 《European Journal of Sport Science》2019,19(5):612-620

The ability to quickly locate objects within the visual field has a significant influence on athletic performance. Saccades are conjugate eye movements responsible for the rapid shift that brings a new part of the visual field into foveal vision. The aim of this study was to investigate the effects of sport expertise and intense physical effort on saccade dynamics during a free-viewing visual search task in skilled soccer players. Two groups of male subjects participated in this study: 18 soccer players and 18 non-athletes as the control group. Two sessions of visual search tasks without a sport-specific design were employed. Eye movements during the visual search tasks were recorded binocularly. Between pre- and post-test sessions, athletes performed a maximal incremental treadmill test. Cardiorespiratory parameters were measured continuously. Capillary lactate samples were collected. Pre-test findings indicated that athletes, in comparison to non-athletes, achieve higher values of the following characteristics of saccades (1) average acceleration, (2) acceleration peak, (3) deceleration peak, and (4) average velocity. An increase in post-test saccade duration and a decrease in post-test saccade velocity was observed in athletes due to the strenuous physical effort in relation to the pre-test state. Athletes may transfer high saccadic function efficiency to non-specific visual stimuli. The findings partially confirm that physical exertion can reduce oculomotor efficiency in athletes.  相似文献   

Distribution of the AMPD1 C34T polymorphism in Polish power-oriented athletes     

Cieszczyk P  Ostanek M  Leońska-Duniec A  Sawczuk M  Maciejewska A  Eider J  Ficek K  Sygit K  Kotarska K 《Journal of sports sciences》2012,30(1):31-35

The aims of this study were to determine the distribution of the AMPD1 genotype among groups of high-level Polish power-oriented athletes, and to investigate potential associations between genetic polymorphism in exon 2 of the AMPD1 gene and power-oriented athlete status. Altogether, 158 male Polish power-oriented athletes were genotyped by PCR-RFLP. The genetic control group comprised 160 unrelated male volunteers. We observed significant differences in genotype distribution when all 158 athletes (89.25% CC, 10.75% CT, 0.00% TT; P = 0.0025) were compared with controls (75.00% CC, 23.75% CT, 1.25% TT). A significant deficiency of the T allele was noted in all subgroups (short-distance runners: 5.21%, P = 0.032; short-distance swimmers: 5.56%, P = 0.031; weightlifters: 5.36%, P = 0.024) compared with controls (13.13%), while this trend was even stronger when the frequency of the T allele was compared between controls and all 158 athletes (5.38%, P = 0.0007). Our results indicate a lower frequency of the AMPD1 exon 2 T34 allele in elite Polish power-oriented athletes. Our data suggest that the C allele may help athletes to attain elite status in power-oriented sports.  相似文献   

Acoustic emission monitoring of an eighteenth-century wardrobe to support a strategy for indoor climate management     

Marcin Strojecki  Leszek Krzemień  Joanna Sobczyk  Łukasz Bratasz 《文物保护研究》2014,59(4):225-232

The on-site monitoring of acoustic emission (AE) has allowed the direct tracing of climate-induced crack propagation in an eighteenth-century wardrobe displayed in the Gallery of Decorative Art in the National Museum in Krakow, Poland. The anti-correlation measuring scheme and frequency filtering allowed very low levels of physical damage to the wardrobe to be detected in spite of the high background noise typical of the museum environment. The total AE energy recorded during two years of monitoring corresponded to a fractured area of 12 mm² or a total crack propagation of 1.2 mm for two10-mm-thick panels. Although the total damage recorded was minute, correlation between the events of fracturing and falls in indoor relative humidity (RH) in winter due to insufficient humidification was evident. The risk of damage, expressed in terms of crack propagation, was quantified as a function of the magnitude of the RH falls of the duration compatible with the response time of the object. The data allow acceptable RH falls to be identified if a conservation professional or a curator selects a ‘tolerable’ yearly propagation of the fracture, in other words the progress of damage considered insignificant.  相似文献   

The impact of the pandemic on early career researchers' work-life and scholarly communications: A quantitative aerial analysis     

David Nicholas  Eti Herman  David Clark  Cherifa Boukacem-Zeghmouri  Blanca Rodríguez-Bravo  Abdullah Abrizah  Anthony Watkinson  David Sims  Marzena 'Świgoń  Jie Xu  Galina Serbina  Hamid R. Jamali  Carol Tenopir  Suzie Allard 《Learned Publishing》2023,36(2):128-140

After two-years of repeat interviewing early career sciences/social sciences researchers from around the world about their work life and scholarly communications in pandemic-times, the Harbingers-2 project is in a position to release quantitative data on the pandemic's overall impact. The data comes from around 50 questions asked in the third and final round of interviews with 147 early career researchers (ECRs), which had a codifiable element to them (such as yes, no, do not know). The 19 scholarly topics covered include: pandemic-related research; research funding; changes to the workplace/working from home; pandemic-incurred stress and anxiety; teaching; employment security; career progression; mentoring; assessment (including metrics); collaboration; searching/finding information; ethics; networking; informal communication; publishing; sharing; pre-prints; outreach; and scholarly transformations. The main findings are that in six broad aspects of ECRs' work-life and scholarly behaviour, more than 50% of ECRs were impacted by the pandemic, with remote teaching having the greatest impact. By way of comparison, in another six aspects there was little change, least of all when it came to sharing activities. Among the countries studied, Malaysia stood out as being the most impacted, and of the disciplines it was the medical sciences and the soft social sciences most impacted.  相似文献   

Virtual laboratory—Using a hand movement recognition system to improve the quality of chemical education     

Robert Wolski  Piotr Jagodziński 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(1):218-231

The rapid development of information and communication technologies has enabled the development of interfaces, which allow the recognition of the gestures and movements of the user. These interfaces, due to their affordable prices, are available to a wide range of users. They are called natural user interfaces (NUI). NUI are commonly used in game consoles and electronic devices, such as smartphones and tablets. We used the Kinect sensor from Microsoft in our studies to identify the movements and gestures of the user. This interface was used by us in teaching Chemistry in a Middle School and High School by developing a virtual chemical laboratory, which is based on a system of hand movements. We have analyzed the gestures and movements of the virtual chemical laboratory user to determine how they raise the effectiveness in chemical education. The results show how much better students work with a virtual laboratory, when studied by us in chemical areas, that concerned remembering information, understanding information, applying their experience in situations familiar to them from school and in solving chemical problems.  相似文献   

Phytases Improve Myo-Inositol Bioaccessibility in Rye Bread: A Study Using an In Vitro Method of Digestion and a Caco-2 Cell Culture Model     

Robert Duliński  Emilia Katarzyna Cielecka  Ma?gorzata Pierzchalska  Krzysztof ?y?a 《Food Technology and Biotechnology》2015,53(1):66-72

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The socio-economic effectiveness of education     

Jan Kluczyński  Michat Gmytrasiewicz 《Higher Education》1972,1(3):333-344

The authors discuss the factors which predetermine research into the effectiveness of education and the role of economics in educational research. Three fundamental research areas are identified: macroeconomic research into the relations between the national economy and culture and the educational system, economic aspects of the functioning of education, and cost-effectiveness in individual terms. The principles of planning and its implications for policy are discussed and the role of research on expenditure and costs defined. The effects of education are shown as being of two kinds, direct and indirect, and their relative importance for planning is considered and illustrated with examples from the authors' own research in Poland. Finally, the quantitative and qualitative aspects of extensive and intensive development policies and their relationship to overall national economic development are investigated and a number of conclusions drawn.

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Résumé Les auteurs discutent les facteurs qui conditionnent la recherche consacrée au rendement de l'éducation ainsi que la rôle de l'économie dans la recherche sur l'éducation. Ils distinguent trois domaines fondamentaux de la recherche: premièrement, la recherche macro-économique portant sur les relations entre la culture ou l'économie nationale et le système d'éducation; deuxièmement les aspects économique du processus d'éducation; troisièmement les études de rendement en fonction du coût de l'éducation par téte. L'article discute les principes de la planification et ses implications en termes de politique de l'éducation et cherche à définir les effets de la recherche sur les dépenses et les coûts. On montre que les conséquences du processus d'éducation sont de deux types et leurs importance relative du point de vue de la planification est mise en évidence et illustrée par des exemples empruntés aux recherches des auteurs sur la Pologne. En conclusion, l'article éclaire les aspects tant quantitatifs que qualitatifs des politiques de développement extensif et intensif de l'éducation dans leurs relations au développement global de l'économie nationale pour en tirer un certain nombre de remarques finales. *** DIRECT SUPPORT *** A0010002 00003

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Higher education in European socialist countries     

Jan Kluczyński 《Prospects》1980,10(2):196-201

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