A continuously variable displacement mechanism, which is composed of a hydraulic control valve with mechanical-positional feedback to camshaft, was designed for changing the displacement of traditional camshaft connec...A continuously variable displacement mechanism, which is composed of a hydraulic control valve with mechanical-positional feedback to camshaft, was designed for changing the displacement of traditional camshaft connecting-rod low speed high torque (LSHT) hydraulic motor continuously. The new type of continuously variable displacement mechanism is simple and easy to be made. The structure and principle of a continuously variable displacement mechanism was introduced. The mathematic model of the continuously variable displacement mechanism was set up and its static and dynamic characteristics were analyzed with the help of computer simulation. It can be seen that the cam ring on camshaft of the traditional LSHT hydraulic motor can stop at any position between minimum and maximum eccentricity, according to an input fluid pressure signal. And it can also stay anywhere stably through self-adjusting. Besides, it can work stabilized when load impact or oil leakage exists.展开更多
The Fork-Join program consisting of K parallel tasks is a useful model for a large number of computing applications. When the parallel processor has multi-channels, later tasks may finish execution earlier than their ...The Fork-Join program consisting of K parallel tasks is a useful model for a large number of computing applications. When the parallel processor has multi-channels, later tasks may finish execution earlier than their earlier tasks and may join with tasks from other programs. This phenomenon is called exchangeable join (EJ), which introduces correlation to the task’s service time. In this work, we investigate the response time of multiprocessor systems with EJ with a new approach. We analyze two aspects of this kind of systems: exchangeable join (EJ) and the capacity constraint (CC). We prove that the system response time can be effectively reduced by EJ, while the reduced amount is constrained by the capacity of the multiprocessor. An upper bound model is constructed based on this analysis and a quick estimation algorithm is proposed. The approximation formula is verified by extensive simulation results, which show that the relative error of approximation is less than 5%.展开更多
To achieve CO2 emissions reductions, the UK Building Regulations require developers of new residential buildings to calculate expected CO2 emissions arising from their energy consumption using a methodology such as St...To achieve CO2 emissions reductions, the UK Building Regulations require developers of new residential buildings to calculate expected CO2 emissions arising from their energy consumption using a methodology such as Standard Assessment Procedure （SAP 2005） or, more recently SAP 2009. SAP encompasses all domestic heat consumption and a limited proportion of the electricity consumption. However, these calculations are rarely verified with real energy consumption and related CO2 emissions. This work presents the results of an analysis based on weekly heat demand data for more than 200 individual fiats. The data were collected from a recently built residential development connected to a district heating network. A method for separating out the domestic hot water （DHW） use and space heating （SH） demand has been developed and these values are compared to the demand calculated using SAP 2005 and SAP 2009 methodologies. The analysis also shows the variation in DHW and SH consumption with size of flats and with tenure （privately owned or social housing）. Evaluation of the space heating consumption also includes an estimate of the heating degree day （HDD） base temperature for each block of fiats and compares this to the average base temperature calculated using the SAP 2005 methodology.展开更多
By using the techniques of partial digestion of cell wall and selective extraction, we examined the cytoskeleton of wheat young leaf cells under scanning electron micro-scope(SEM). A 3-dimensional cytoskeletal system,...By using the techniques of partial digestion of cell wall and selective extraction, we examined the cytoskeleton of wheat young leaf cells under scanning electron micro-scope(SEM). A 3-dimensional cytoskeletal system, showing some new features, was observed. The cortical network located beneath the cross wall was an anastomosing organization. The association of nucleus with the cell wall by some skeletal filaments was also found. It is noticeable that there were cytoskeletal filaments, which passed through cell wall and connected together with cytoskeletal arrays of adjacent cells. Thus, it is possible that an integral skeletal network existed within the young leaf tissue of wheat.展开更多
This study presents a comparison between three different fonts in order to know the possible influence they may have when used in educational materials for children with readers difficulties resulting from dyslexia. T...This study presents a comparison between three different fonts in order to know the possible influence they may have when used in educational materials for children with readers difficulties resulting from dyslexia. Two of the three selected fonts （Arial and MeMimas） are frequently used in textbooks in Spain. The third type of letter （Dixy） was specially developed for typographic research purposes, following graphic features that according to literature and previous studies on reading patterns favor the dyslexic, and could improve reading skills in these individuals. To examine the quality of reading （speed and accuracy） between fonts, a small--but significant--sample was used. Ten children in Madrid, from eight to 10 years old were examined while reading words and pseudowords with three different fonts （Arial, MeMimas, and Dixy）. The result of the study shows the influence of the shapes of the letters in the legibility of texts with familiar and unfamiliar words （pseudowords） in children with dyslexia. The study showed that using the font Dixy, despite not being known by the children, reading is more accurate than using fonts known to them, such as Arial and MeMimas. As to the reading speed, the results indicate that, although the Dixy is a font never seen before by the children, reading speed is similar to a known font for them, as is the Arial, and greater than a hand writing font such as MeMimas.展开更多
In order to comply with the trend of global climate change,countries are gradually promoting energy conservation and emission reduction,and prefabricated buildings have become one of the main paths for the constructio...In order to comply with the trend of global climate change,countries are gradually promoting energy conservation and emission reduction,and prefabricated buildings have become one of the main paths for the construction industry to develop towards carbon peaking and carbon neutrality goals.This paper takes the box-shaped column flange connection achieved by plug welding-core sleeve in the dormitory building of Tongzhou Campus of the Affiliated High School of Capital Normal University in China as the research object.Based on the consumption quota of prefabricated construction projects and the actual project quantity,the carbon emissions of steel structure column connection joints at different phases are calculated by the emission factor method,and it is proposed that the production consumption of building materials plays a key role in energy conservation and emission reduction.This paper concludes that the box-shaped column flange connection achieved by plug welding-core sleeve in the construction phase of an assembled steel building emits 49.5%less carbon dioxide than a conventional full fusion-welded joint.And the reason for the high carbon emissions of the latter is mainly from the amount of materials and machinery required for full penetration welding.It further affirms the green and environmental protection effect of the assembled steel structure plug welding-core sleeve flange connection joint in actual projects,and provides a reference for related research.展开更多
文摘A continuously variable displacement mechanism, which is composed of a hydraulic control valve with mechanical-positional feedback to camshaft, was designed for changing the displacement of traditional camshaft connecting-rod low speed high torque (LSHT) hydraulic motor continuously. The new type of continuously variable displacement mechanism is simple and easy to be made. The structure and principle of a continuously variable displacement mechanism was introduced. The mathematic model of the continuously variable displacement mechanism was set up and its static and dynamic characteristics were analyzed with the help of computer simulation. It can be seen that the cam ring on camshaft of the traditional LSHT hydraulic motor can stop at any position between minimum and maximum eccentricity, according to an input fluid pressure signal. And it can also stay anywhere stably through self-adjusting. Besides, it can work stabilized when load impact or oil leakage exists.
基金Project supported by the National Natural Science Foundation of0 China (Nos. 60274011 and 60574067), and the Program for NewCentury Excellent Talents in University (No. NCET-04-0094), China
文摘The Fork-Join program consisting of K parallel tasks is a useful model for a large number of computing applications. When the parallel processor has multi-channels, later tasks may finish execution earlier than their earlier tasks and may join with tasks from other programs. This phenomenon is called exchangeable join (EJ), which introduces correlation to the task’s service time. In this work, we investigate the response time of multiprocessor systems with EJ with a new approach. We analyze two aspects of this kind of systems: exchangeable join (EJ) and the capacity constraint (CC). We prove that the system response time can be effectively reduced by EJ, while the reduced amount is constrained by the capacity of the multiprocessor. An upper bound model is constructed based on this analysis and a quick estimation algorithm is proposed. The approximation formula is verified by extensive simulation results, which show that the relative error of approximation is less than 5%.
文摘To achieve CO2 emissions reductions, the UK Building Regulations require developers of new residential buildings to calculate expected CO2 emissions arising from their energy consumption using a methodology such as Standard Assessment Procedure （SAP 2005） or, more recently SAP 2009. SAP encompasses all domestic heat consumption and a limited proportion of the electricity consumption. However, these calculations are rarely verified with real energy consumption and related CO2 emissions. This work presents the results of an analysis based on weekly heat demand data for more than 200 individual fiats. The data were collected from a recently built residential development connected to a district heating network. A method for separating out the domestic hot water （DHW） use and space heating （SH） demand has been developed and these values are compared to the demand calculated using SAP 2005 and SAP 2009 methodologies. The analysis also shows the variation in DHW and SH consumption with size of flats and with tenure （privately owned or social housing）. Evaluation of the space heating consumption also includes an estimate of the heating degree day （HDD） base temperature for each block of fiats and compares this to the average base temperature calculated using the SAP 2005 methodology.
文摘By using the techniques of partial digestion of cell wall and selective extraction, we examined the cytoskeleton of wheat young leaf cells under scanning electron micro-scope(SEM). A 3-dimensional cytoskeletal system, showing some new features, was observed. The cortical network located beneath the cross wall was an anastomosing organization. The association of nucleus with the cell wall by some skeletal filaments was also found. It is noticeable that there were cytoskeletal filaments, which passed through cell wall and connected together with cytoskeletal arrays of adjacent cells. Thus, it is possible that an integral skeletal network existed within the young leaf tissue of wheat.
文摘This study presents a comparison between three different fonts in order to know the possible influence they may have when used in educational materials for children with readers difficulties resulting from dyslexia. Two of the three selected fonts （Arial and MeMimas） are frequently used in textbooks in Spain. The third type of letter （Dixy） was specially developed for typographic research purposes, following graphic features that according to literature and previous studies on reading patterns favor the dyslexic, and could improve reading skills in these individuals. To examine the quality of reading （speed and accuracy） between fonts, a small--but significant--sample was used. Ten children in Madrid, from eight to 10 years old were examined while reading words and pseudowords with three different fonts （Arial, MeMimas, and Dixy）. The result of the study shows the influence of the shapes of the letters in the legibility of texts with familiar and unfamiliar words （pseudowords） in children with dyslexia. The study showed that using the font Dixy, despite not being known by the children, reading is more accurate than using fonts known to them, such as Arial and MeMimas. As to the reading speed, the results indicate that, although the Dixy is a font never seen before by the children, reading speed is similar to a known font for them, as is the Arial, and greater than a hand writing font such as MeMimas.
基金funded by National Natural Science Foundation of China,grant number 51778036Joint Program of Beijing Natural Science Foundation and Education Commission,grant number KZ201910016018.
文摘In order to comply with the trend of global climate change,countries are gradually promoting energy conservation and emission reduction,and prefabricated buildings have become one of the main paths for the construction industry to develop towards carbon peaking and carbon neutrality goals.This paper takes the box-shaped column flange connection achieved by plug welding-core sleeve in the dormitory building of Tongzhou Campus of the Affiliated High School of Capital Normal University in China as the research object.Based on the consumption quota of prefabricated construction projects and the actual project quantity,the carbon emissions of steel structure column connection joints at different phases are calculated by the emission factor method,and it is proposed that the production consumption of building materials plays a key role in energy conservation and emission reduction.This paper concludes that the box-shaped column flange connection achieved by plug welding-core sleeve in the construction phase of an assembled steel building emits 49.5%less carbon dioxide than a conventional full fusion-welded joint.And the reason for the high carbon emissions of the latter is mainly from the amount of materials and machinery required for full penetration welding.It further affirms the green and environmental protection effect of the assembled steel structure plug welding-core sleeve flange connection joint in actual projects,and provides a reference for related research.
