Testing the parts of mechanical products and ensuring their accuracy to the design requirements are essential to products’ quality, market competitiveness and manufacturers’ maximum economical benefits from these pr...Testing the parts of mechanical products and ensuring their accuracy to the design requirements are essential to products’ quality, market competitiveness and manufacturers’ maximum economical benefits from these products. One of the latest subjects of study in the area of precision measurement is the testing of parts to follow the relative requirements, viz. design requirements for the size tolerance of size features and related geometrical tolerances of the central feature, including the envelope requirement, maximum material requirement and least material requirement. The article analyzes test methods for parts to follow the envelope requirement or maximum material requirement, as well as further requirements of geometrical tolerances for its central feature. The method is effective in improving product quality and rejecting unqualified parts.展开更多
This paper presents a character table of S_4 wr S_2 wreath product group.Using this character table,~1H or ^(13)C NMR spectra analysis of molecula with S_4[S_2]symmetry,especially simplification of the secular determi...This paper presents a character table of S_4 wr S_2 wreath product group.Using this character table,~1H or ^(13)C NMR spectra analysis of molecula with S_4[S_2]symmetry,especially simplification of the secular determinant equation will be easy to carry out. Molecules with S_4[S_2]symmetry,are exemplified by octaphenylcyclo- tetrasiloxane and 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine chromium (Ⅲ)chloride.展开更多
This paper studied the residents＇ level of satisfaction in public housing units in Shenyang of China which aimed to identify how each housing unit feature correlates with the residents＇ overall satisfaction and impl...This paper studied the residents＇ level of satisfaction in public housing units in Shenyang of China which aimed to identify how each housing unit feature correlates with the residents＇ overall satisfaction and implication on policy and design. The discussion is based on a questionnaire survey conducted in 2011. This research concluded that more residents were satisfied with the housing unit features than those who were dissatisfied, while some remarkable differences could be observed if comparative analysis between two different public housing types in China were studied. The affordable housing residents are generally more satisfied with housing unit features than those living in low-rent housing. The most dissatisfying feature is the living room, followed by unit size and the floor plan. Additionally, the living room and the floor plans were features which were highly and positively correlated to the residents＇ overall satisfaction of housing unit features. Consequently, improving the living room size and the design of housing unit floor plans would clearly be beneficial to alleviating residents＇ dissatisfaction to the housing units.展开更多
The aim of this study is to investigate the effect of auditor type and eamings reporting lag on the cost of debt for the Tunisian setting. Our sample consists of 32 Tunisian companies for the period of 2003-2012. Audi...The aim of this study is to investigate the effect of auditor type and eamings reporting lag on the cost of debt for the Tunisian setting. Our sample consists of 32 Tunisian companies for the period of 2003-2012. Audit quality is measured by auditor size （Big 4 versus non-Big 4） and timely disclosure is proxied by earnings reporting lag. Results show that auditor type is negatively associated with the cost of debt. By contrast, the association between earnings announcement lag and the cost of debt is positive and significant. When testing for the moderating effects of industry and listing status, we document that these associations are more pronounced for industrial companies and listed firms. Finally, the period of investigation slightly moderates the examined associations, since financial institutions become more sensitive to the tardy communication of information and less concerned with auditor type following some economic and political troubles in Tunisia between 2010 and 2012. Our findings have policy implications for managers in the Tunisian setting and other developing economies similar to Tunisia given the crucial role played by debt as an important source of external finance for companies.展开更多
A single-axis normal-tracking measurement system is proposed, which can solve the problem of measuring large curved surface. According to Collins formula, the tilt dependent error of the measurement system is studied,...A single-axis normal-tracking measurement system is proposed, which can solve the problem of measuring large curved surface. According to Collins formula, the tilt dependent error of the measurement system is studied, which uses Gaussian beam as the light source. By theoretical analysis and numerical simulation, the influence of the error is presented. The results show that there is the difference between point source and Gaussian beam for differential confocal microscopy. The opti-mal diameter of pinhole can be determined by the mathematical model and the actual parameters of the measurement system. The optimal pinhole diameter of this measurement system is 20 to 35 pm for 633 nm wavelength light source.展开更多
Wind microturbines typically have rotor diameters of 2 m or less. This paper presents theoretical expressions that can be used to determine the aerodynamic performance of wind microturbines. A commercially-available t...Wind microturbines typically have rotor diameters of 2 m or less. This paper presents theoretical expressions that can be used to determine the aerodynamic performance of wind microturbines. A commercially-available three-bladed microturbine was tested at the outlet plane of a wind tunnel. The cross-section dimensions of the wind tunnel jet are 2.5 m （horizontal） x 1.5 m （vertical）. The tested microturbine has a diameter of 1.2 m, and it generates a maximum power output of about 300 W. The paper provides the wind tunnel test methodology that was used to determine the mean and fluctuating forces generated by the aforementioned wind microturbine. Both the static and dynamic responses of the turbine were measured, and results from this testing are presented in this paper. These results enable the trends and predictions of the theoretical expressions to be compared with wind tunnel measurements. It is shown that, for this particular microturbine, the behaviours of these test measurements are consistent with the expected theoretical predictions.展开更多
During the last decade, a great deal of activity has been devoted to the calculation of the HilbertPoincar′e series of unitary highest weight representations and related modules in algebraic geometry. However,uniform...During the last decade, a great deal of activity has been devoted to the calculation of the HilbertPoincar′e series of unitary highest weight representations and related modules in algebraic geometry. However,uniform formulas remain elusive—even for more basic invariants such as the Gelfand-Kirillov dimension or the Bernstein degree, and are usually limited to families of representations in a dual pair setting. We use earlier work by Joseph to provide an elementary and intrinsic proof of a uniform formula for the Gelfand-Kirillov dimension of an arbitrary unitary highest weight module in terms of its highest weight. The formula generalizes a result of Enright and Willenbring(in the dual pair setting) and is inspired by Wang's formula for the dimension of a minimal nilpotent orbit.展开更多
文摘Testing the parts of mechanical products and ensuring their accuracy to the design requirements are essential to products’ quality, market competitiveness and manufacturers’ maximum economical benefits from these products. One of the latest subjects of study in the area of precision measurement is the testing of parts to follow the relative requirements, viz. design requirements for the size tolerance of size features and related geometrical tolerances of the central feature, including the envelope requirement, maximum material requirement and least material requirement. The article analyzes test methods for parts to follow the envelope requirement or maximum material requirement, as well as further requirements of geometrical tolerances for its central feature. The method is effective in improving product quality and rejecting unqualified parts.
文摘This paper presents a character table of S_4 wr S_2 wreath product group.Using this character table,~1H or ^(13)C NMR spectra analysis of molecula with S_4[S_2]symmetry,especially simplification of the secular determinant equation will be easy to carry out. Molecules with S_4[S_2]symmetry,are exemplified by octaphenylcyclo- tetrasiloxane and 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine chromium (Ⅲ)chloride.
文摘This paper studied the residents＇ level of satisfaction in public housing units in Shenyang of China which aimed to identify how each housing unit feature correlates with the residents＇ overall satisfaction and implication on policy and design. The discussion is based on a questionnaire survey conducted in 2011. This research concluded that more residents were satisfied with the housing unit features than those who were dissatisfied, while some remarkable differences could be observed if comparative analysis between two different public housing types in China were studied. The affordable housing residents are generally more satisfied with housing unit features than those living in low-rent housing. The most dissatisfying feature is the living room, followed by unit size and the floor plan. Additionally, the living room and the floor plans were features which were highly and positively correlated to the residents＇ overall satisfaction of housing unit features. Consequently, improving the living room size and the design of housing unit floor plans would clearly be beneficial to alleviating residents＇ dissatisfaction to the housing units.
文摘The aim of this study is to investigate the effect of auditor type and eamings reporting lag on the cost of debt for the Tunisian setting. Our sample consists of 32 Tunisian companies for the period of 2003-2012. Audit quality is measured by auditor size （Big 4 versus non-Big 4） and timely disclosure is proxied by earnings reporting lag. Results show that auditor type is negatively associated with the cost of debt. By contrast, the association between earnings announcement lag and the cost of debt is positive and significant. When testing for the moderating effects of industry and listing status, we document that these associations are more pronounced for industrial companies and listed firms. Finally, the period of investigation slightly moderates the examined associations, since financial institutions become more sensitive to the tardy communication of information and less concerned with auditor type following some economic and political troubles in Tunisia between 2010 and 2012. Our findings have policy implications for managers in the Tunisian setting and other developing economies similar to Tunisia given the crucial role played by debt as an important source of external finance for companies.
基金Quantity Dissemination and Quality Safety Project of AQSIQ(No.ALC1501)National Key Scientific Instrument and Equipment Development Projects,China(No.2013YQ170539)
文摘A single-axis normal-tracking measurement system is proposed, which can solve the problem of measuring large curved surface. According to Collins formula, the tilt dependent error of the measurement system is studied, which uses Gaussian beam as the light source. By theoretical analysis and numerical simulation, the influence of the error is presented. The results show that there is the difference between point source and Gaussian beam for differential confocal microscopy. The opti-mal diameter of pinhole can be determined by the mathematical model and the actual parameters of the measurement system. The optimal pinhole diameter of this measurement system is 20 to 35 pm for 633 nm wavelength light source.
文摘Wind microturbines typically have rotor diameters of 2 m or less. This paper presents theoretical expressions that can be used to determine the aerodynamic performance of wind microturbines. A commercially-available three-bladed microturbine was tested at the outlet plane of a wind tunnel. The cross-section dimensions of the wind tunnel jet are 2.5 m （horizontal） x 1.5 m （vertical）. The tested microturbine has a diameter of 1.2 m, and it generates a maximum power output of about 300 W. The paper provides the wind tunnel test methodology that was used to determine the mean and fluctuating forces generated by the aforementioned wind microturbine. Both the static and dynamic responses of the turbine were measured, and results from this testing are presented in this paper. These results enable the trends and predictions of the theoretical expressions to be compared with wind tunnel measurements. It is shown that, for this particular microturbine, the behaviours of these test measurements are consistent with the expected theoretical predictions.
基金supported by National Natural Science Foundation of China(Grant No.11171324)the Hong Kong Research Grants Council under RGC Project(Grant No.60311)the Hong Kong University of Science and Technology under DAG S09/10.SC02.
文摘During the last decade, a great deal of activity has been devoted to the calculation of the HilbertPoincar′e series of unitary highest weight representations and related modules in algebraic geometry. However,uniform formulas remain elusive—even for more basic invariants such as the Gelfand-Kirillov dimension or the Bernstein degree, and are usually limited to families of representations in a dual pair setting. We use earlier work by Joseph to provide an elementary and intrinsic proof of a uniform formula for the Gelfand-Kirillov dimension of an arbitrary unitary highest weight module in terms of its highest weight. The formula generalizes a result of Enright and Willenbring(in the dual pair setting) and is inspired by Wang's formula for the dimension of a minimal nilpotent orbit.
