Background：Stiffness is commonly assessed in relation to injury and athletic performance.The purpose of this research was to compare the validity and reliability of 3 in vivo methods of stiffness assessment using 1 c...Background：Stiffness is commonly assessed in relation to injury and athletic performance.The purpose of this research was to compare the validity and reliability of 3 in vivo methods of stiffness assessment using 1 cohort of participants.Methods：To determine inter-day reliability,15 female netballers were assessed for stiffness twice within 1 week using unilateral hopping（vertical stiffness）,free oscillations of the calf,and myometry of various muscles of the triceps surae.To establish convergent construct validity,stiffness was compared to static and dynamic strength measurements.Results：Test–retest stiffness results revealed that vertical stiffness produced moderate to high reliability results and myometry presented moderate to very high reliability.In contrast,the free oscillation technique displayed low to moderate reliability.Vertical stiffness demonstrated a significa t correlation with rate of force development during a squat jump,whilst myometer stiffness measurements from 3 sites in the lower limb revealed significan correlations with isometric rate of force development.Further,significan negative correlations were evident between the eccentric utilisation ratio and various myometer stiffness results.No relationships were established between the free oscillation technique and any of the performance measurements.Conclusion：These results suggest that vertical stiffness and myometry are valid and reliable methods for assessing stiffness.展开更多
To make a detailed test on the reliability and detection performance of the electrochemical concentra- tion cell （ECC） type ozonesonde which had been devel- oped and preliminarily evaluated by the authors, an inten-...To make a detailed test on the reliability and detection performance of the electrochemical concentra- tion cell （ECC） type ozonesonde which had been devel- oped and preliminarily evaluated by the authors, an inten- sive ozonesonde release experiment was held at two sites in Beijing and Changchun in June 2013. The results showed that the mean background current and its standard deviation were 0.03 （0.04） pA and 0.02 （0.03） pA in Bei- jing （Changchun）. The average response time and its standard deviation were 27.8 s （30.4 s） and 4.0 s （3.7 s） in Beijing （Changchun）. The ozone partial pressure profiles at both sites showed a central peak in the stratosphere and a side peak in the boundary layer. Large variation in ozone partial pressure was observed at the middle levels of the atmosphere （10-17 kin）. A more marked gradient of ozone change was observed in Beijing （3.4 mPa km-1） at the lower atmosphere level, as compared to that in Changchun （0.4 mPa km-l）. The results presented in this paper indicate that this self-developed ozonesonde shows a high level of reliability and good performance. The ozonsonde is expected to play an important role in opera- tional observations of ozone profiles.展开更多
Since the reform and opening-up program started in 1978,the level of urbanization has increased rapidly in China.Rapid urban expansion and restructuring have had significant impacts on the ecological environment espec...Since the reform and opening-up program started in 1978,the level of urbanization has increased rapidly in China.Rapid urban expansion and restructuring have had significant impacts on the ecological environment especially within built-up areas.In this study,ArcGIS 10,ENVI 4.5,and Visual FoxPro 6.0 were used to analyze the human impacts on vegetation in the built-up areas of 656Chinese cities from 1992 to 2010.Firstly,an existing algorithm was refined to extract the boundaries of the built-up areas based on the Defense Meteorological Satellite Program Operational Linescan System(DMSP_OLS)nighttime light data.This improved algorithm has the advantages of high accuracy and speed.Secondly,a mathematical model(Human impacts(HI))was constructed to measure the impacts of human factors on vegetation during rapid urbanization based on Advanced Very High Resolution Radiometer(AVHRR)Normalized Difference Vegetation Index(NDVI)and Moderate Resolution Imaging Spectroradiometer(MODIS)NDVI.HI values greater than zero indicate relatively beneficial effects while values less than zero indicate proportionally adverse effects.The results were analyzed from four aspects:the size of cities(metropolises,large cities,medium-sized cities,and small cities),large regions(the eastern,central,western,and northeastern China),administrative divisions of China(provinces,autonomous regions,and municipalities)and vegetation zones(humid and semi-humid forest zone,semi-arid steppe zone,and arid desert zone).Finally,we discussed how human factors impacted on vegetation changes in the built-up areas.We found that urban planning policies and developmental stages impacted on vegetation changes in the built-up areas.The negative human impacts followed an inverted′U′shape,first rising and then falling with increase of urban scales.China′s national policies,social and economic development affected vegetation changes in the built-up areas.The findings can provide a scientific basis for municipal planning departments,a decision-making reference for government,and scientific guidance for sustainable development in China.展开更多
Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propaga- tion eharaeteristi...Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propaga- tion eharaeteristics are proposed for the field test of Chinese 4th generation （4G） trial system. The mea- surement system is established for 3.5GHz based on the sophistieated measurement instruments and the virtual instrument teehnology. The characteristic parameters of radio propagation sueh as path loss （PL） exponent and shadow fading standard deviation are extracted from measurement data, which result in the path loss model finally. The comparisons with other existing international models results validate our mea- surement in terms of path loss model. Based on the analysis of the existing extension model assumed for the microwave frequency at 3.5GHz, we find that the Stanford University Interim （SUI） model fits very well with the measurement result in the hotspot scenario, while the COST 231 model is closer to the mea- surement result in the suburban scenario. This result provides a measurement-based channel referenee for the development of the future IMT-Advanced systems in China.展开更多
An effective and simple way to develop equations from impact strain signals was proposed.Little research has been performed in this area,but this equation is very important for evaluating input signals in finite eleme...An effective and simple way to develop equations from impact strain signals was proposed.Little research has been performed in this area,but this equation is very important for evaluating input signals in finite element analysis impact tests and for obtaining additional information on material deformation and fracture processes under impact loading.For this purpose,dynamic impact responses were examined through signals obtained from a strain gauge installed on an impact striker connected to a data acquisition system.Aluminium 6061-T6 was used to extract strain responses on the striker during Charpy impact testing.Statistical analysis was performed using the I-kaz method,and curve fitting equations based on the equation for vibration response under a non-periodic force were used to evaluate the Charpy impact signals.The I-kaz coefficients and curve fitting equations were then compared and discussed with related parameters,such as velocities and thicknesses.Velocity and thickness were found to be related to the strain signal patterns,curve fitting equations and I-kaz coefficients.The equations developed using this method had R2 values greater than 97.7%.Finally,the constructed equations were determined to be suitable for evaluating Charpy impact strain signal patterns and obtaining additional information on fracture processes under impact loading.展开更多
Ventilation fans are one of the most important pieces of equipment in coal mines. Their performance plays an important role in the safety of staff and production. Given the actual requirements of coal mine production,...Ventilation fans are one of the most important pieces of equipment in coal mines. Their performance plays an important role in the safety of staff and production. Given the actual requirements of coal mine production,we instituted a research project on the measurement methods of key performance parameters such as wind pressure,amount of ventilation and power. At the end a virtual instrument for mine ventilation fans performance evaluation was developed using a USB interface. The practical performance and analytical results of our experiments show that it is feasible,reliable and effective to use the proposed instrumentation for mine ventilation performance evaluation.展开更多
POE （post-occupancy evaluation） of buildings is one of the most important mechanisms which ensures that ceremonial and public building performance including its facilities is sustained. POE studies concerned with ef...POE （post-occupancy evaluation） of buildings is one of the most important mechanisms which ensures that ceremonial and public building performance including its facilities is sustained. POE studies concerned with efficiency of building performance after using and implementing with the end-user. It provides feedback on the current status of the building and proposes solutions to existing problems in addition to guidelines and design criteria for the best solutions in the future. Despite precedent research which have been undertaken in the context of building performance, aspects of evaluating building performance have not been specified and used widely in Jordan. At the commencement of this research, the concept of POE is still new in Jordan, and the local building practitioners are still unfamiliar with this approach for the evaluation of a building performance in Amman. Accordingly, there is a need to undertake this kind of research in Jordan to identify the main guidelines of POE to be applied effectively in ceremonial and public buildings. This study therefore applies POE of indoor environment of the public buildings by exploring the guidelines that can constitute a successful and effective framework for the public buildings in Amman. This was achieved using the learnt lessons from Amman City Hall building which was used as a case study and reflecting them on these where needed. Analytical and descriptive approach basis was applied, adopting a mixed method approach （qualitative and quantitative method） by using observation tool and a questionnaire survey with occupants. Context-derived data and statistics analyzed together were used to explore the guidelines of POE to be applied effectively in public buildings. A field visit and observation tool was adopted for gathering information leading to the findings and recommendations. A questionnaire was also used to extrapolate core findings of this research. This research provides a significant contribution of POE result towards improving indoor environment to ceremonial and public buildings in Jordan.展开更多
The acute （15 minutes-4 hours） effects of exposure to the inhaled DEE （diesel exhaust emitted） on blood parameters of Guinea pigs Cavia porcellus were assessed via CBC （complete blood count） as an indicator usin...The acute （15 minutes-4 hours） effects of exposure to the inhaled DEE （diesel exhaust emitted） on blood parameters of Guinea pigs Cavia porcellus were assessed via CBC （complete blood count） as an indicator using an automated blood analyzer machines （Cell DYN 1700）. The results showed significant changes in some parameters in comparison with control animals started as early as 15 minutes and intensified by the continuous exposure time, leading to significant increase （p 〈 0.05） in the number of both WBC （white blood cells）, PLT （blood platelets） and decrease in numbers of RBC （red blood corpuscles） while hemoglobin percentages （Hb%） showed an insignificant （p 〉 0.05） fluctuating rhythm. The percentages of both Neutrophil and Lymphocyt recorded a significant increase （p 〈 0.05） 1 hour post-exposure to the DEE while other WBCs showed less changes. It is concluded that blood components are so sensitive to DEE and do respond quicker to inhaled pollutants via changes in some components of WBC% but decrease in RBC% and the likelihood of blood clotting due to increase in blood platelets. These results indicate the acute toxic risks of the exposure to DEE of mechanics and technicians who work in vicinity of DEE sources or/and spend most daily hours in semi closed areas.展开更多
文摘Background：Stiffness is commonly assessed in relation to injury and athletic performance.The purpose of this research was to compare the validity and reliability of 3 in vivo methods of stiffness assessment using 1 cohort of participants.Methods：To determine inter-day reliability,15 female netballers were assessed for stiffness twice within 1 week using unilateral hopping（vertical stiffness）,free oscillations of the calf,and myometry of various muscles of the triceps surae.To establish convergent construct validity,stiffness was compared to static and dynamic strength measurements.Results：Test–retest stiffness results revealed that vertical stiffness produced moderate to high reliability results and myometry presented moderate to very high reliability.In contrast,the free oscillation technique displayed low to moderate reliability.Vertical stiffness demonstrated a significa t correlation with rate of force development during a squat jump,whilst myometer stiffness measurements from 3 sites in the lower limb revealed significan correlations with isometric rate of force development.Further,significan negative correlations were evident between the eccentric utilisation ratio and various myometer stiffness results.No relationships were established between the free oscillation technique and any of the performance measurements.Conclusion：These results suggest that vertical stiffness and myometry are valid and reliable methods for assessing stiffness.
基金supported by the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant No.XDB05020503)the Special Fund for Public Welfare Industry (Meteorology) (Grant No.GYHY201106041)
文摘To make a detailed test on the reliability and detection performance of the electrochemical concentra- tion cell （ECC） type ozonesonde which had been devel- oped and preliminarily evaluated by the authors, an inten- sive ozonesonde release experiment was held at two sites in Beijing and Changchun in June 2013. The results showed that the mean background current and its standard deviation were 0.03 （0.04） pA and 0.02 （0.03） pA in Bei- jing （Changchun）. The average response time and its standard deviation were 27.8 s （30.4 s） and 4.0 s （3.7 s） in Beijing （Changchun）. The ozone partial pressure profiles at both sites showed a central peak in the stratosphere and a side peak in the boundary layer. Large variation in ozone partial pressure was observed at the middle levels of the atmosphere （10-17 kin）. A more marked gradient of ozone change was observed in Beijing （3.4 mPa km-1） at the lower atmosphere level, as compared to that in Changchun （0.4 mPa km-l）. The results presented in this paper indicate that this self-developed ozonesonde shows a high level of reliability and good performance. The ozonsonde is expected to play an important role in opera- tional observations of ozone profiles.
基金Under the auspices of National Natural Science Foundation of China(No.41171143,40771064)Program for New Century Excellent Talents in University(No.NCET-07-0398)Fundamental Research Funds for the Central Universities(No.lzu-jbky-2012-k35)
文摘Since the reform and opening-up program started in 1978,the level of urbanization has increased rapidly in China.Rapid urban expansion and restructuring have had significant impacts on the ecological environment especially within built-up areas.In this study,ArcGIS 10,ENVI 4.5,and Visual FoxPro 6.0 were used to analyze the human impacts on vegetation in the built-up areas of 656Chinese cities from 1992 to 2010.Firstly,an existing algorithm was refined to extract the boundaries of the built-up areas based on the Defense Meteorological Satellite Program Operational Linescan System(DMSP_OLS)nighttime light data.This improved algorithm has the advantages of high accuracy and speed.Secondly,a mathematical model(Human impacts(HI))was constructed to measure the impacts of human factors on vegetation during rapid urbanization based on Advanced Very High Resolution Radiometer(AVHRR)Normalized Difference Vegetation Index(NDVI)and Moderate Resolution Imaging Spectroradiometer(MODIS)NDVI.HI values greater than zero indicate relatively beneficial effects while values less than zero indicate proportionally adverse effects.The results were analyzed from four aspects:the size of cities(metropolises,large cities,medium-sized cities,and small cities),large regions(the eastern,central,western,and northeastern China),administrative divisions of China(provinces,autonomous regions,and municipalities)and vegetation zones(humid and semi-humid forest zone,semi-arid steppe zone,and arid desert zone).Finally,we discussed how human factors impacted on vegetation changes in the built-up areas.We found that urban planning policies and developmental stages impacted on vegetation changes in the built-up areas.The negative human impacts followed an inverted′U′shape,first rising and then falling with increase of urban scales.China′s national policies,social and economic development affected vegetation changes in the built-up areas.The findings can provide a scientific basis for municipal planning departments,a decision-making reference for government,and scientific guidance for sustainable development in China.
基金supported by the High Technology Research and Development Programme of China(2007AA01Z278)
文摘Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propaga- tion eharaeteristics are proposed for the field test of Chinese 4th generation （4G） trial system. The mea- surement system is established for 3.5GHz based on the sophistieated measurement instruments and the virtual instrument teehnology. The characteristic parameters of radio propagation sueh as path loss （PL） exponent and shadow fading standard deviation are extracted from measurement data, which result in the path loss model finally. The comparisons with other existing international models results validate our mea- surement in terms of path loss model. Based on the analysis of the existing extension model assumed for the microwave frequency at 3.5GHz, we find that the Stanford University Interim （SUI） model fits very well with the measurement result in the hotspot scenario, while the COST 231 model is closer to the mea- surement result in the suburban scenario. This result provides a measurement-based channel referenee for the development of the future IMT-Advanced systems in China.
基金Universiti Kebangsaan Malaysia grant UKM-KK-03-FRGS 0118-2010Universiti Teknikal Malaysia Melaka for supporting these research activities
文摘An effective and simple way to develop equations from impact strain signals was proposed.Little research has been performed in this area,but this equation is very important for evaluating input signals in finite element analysis impact tests and for obtaining additional information on material deformation and fracture processes under impact loading.For this purpose,dynamic impact responses were examined through signals obtained from a strain gauge installed on an impact striker connected to a data acquisition system.Aluminium 6061-T6 was used to extract strain responses on the striker during Charpy impact testing.Statistical analysis was performed using the I-kaz method,and curve fitting equations based on the equation for vibration response under a non-periodic force were used to evaluate the Charpy impact signals.The I-kaz coefficients and curve fitting equations were then compared and discussed with related parameters,such as velocities and thicknesses.Velocity and thickness were found to be related to the strain signal patterns,curve fitting equations and I-kaz coefficients.The equations developed using this method had R2 values greater than 97.7%.Finally,the constructed equations were determined to be suitable for evaluating Charpy impact strain signal patterns and obtaining additional information on fracture processes under impact loading.
基金Project 2007E237 supported by the Science Fund Program of Shaanxi Province of China
文摘Ventilation fans are one of the most important pieces of equipment in coal mines. Their performance plays an important role in the safety of staff and production. Given the actual requirements of coal mine production,we instituted a research project on the measurement methods of key performance parameters such as wind pressure,amount of ventilation and power. At the end a virtual instrument for mine ventilation fans performance evaluation was developed using a USB interface. The practical performance and analytical results of our experiments show that it is feasible,reliable and effective to use the proposed instrumentation for mine ventilation performance evaluation.
文摘POE （post-occupancy evaluation） of buildings is one of the most important mechanisms which ensures that ceremonial and public building performance including its facilities is sustained. POE studies concerned with efficiency of building performance after using and implementing with the end-user. It provides feedback on the current status of the building and proposes solutions to existing problems in addition to guidelines and design criteria for the best solutions in the future. Despite precedent research which have been undertaken in the context of building performance, aspects of evaluating building performance have not been specified and used widely in Jordan. At the commencement of this research, the concept of POE is still new in Jordan, and the local building practitioners are still unfamiliar with this approach for the evaluation of a building performance in Amman. Accordingly, there is a need to undertake this kind of research in Jordan to identify the main guidelines of POE to be applied effectively in ceremonial and public buildings. This study therefore applies POE of indoor environment of the public buildings by exploring the guidelines that can constitute a successful and effective framework for the public buildings in Amman. This was achieved using the learnt lessons from Amman City Hall building which was used as a case study and reflecting them on these where needed. Analytical and descriptive approach basis was applied, adopting a mixed method approach （qualitative and quantitative method） by using observation tool and a questionnaire survey with occupants. Context-derived data and statistics analyzed together were used to explore the guidelines of POE to be applied effectively in public buildings. A field visit and observation tool was adopted for gathering information leading to the findings and recommendations. A questionnaire was also used to extrapolate core findings of this research. This research provides a significant contribution of POE result towards improving indoor environment to ceremonial and public buildings in Jordan.
文摘The acute （15 minutes-4 hours） effects of exposure to the inhaled DEE （diesel exhaust emitted） on blood parameters of Guinea pigs Cavia porcellus were assessed via CBC （complete blood count） as an indicator using an automated blood analyzer machines （Cell DYN 1700）. The results showed significant changes in some parameters in comparison with control animals started as early as 15 minutes and intensified by the continuous exposure time, leading to significant increase （p 〈 0.05） in the number of both WBC （white blood cells）, PLT （blood platelets） and decrease in numbers of RBC （red blood corpuscles） while hemoglobin percentages （Hb%） showed an insignificant （p 〉 0.05） fluctuating rhythm. The percentages of both Neutrophil and Lymphocyt recorded a significant increase （p 〈 0.05） 1 hour post-exposure to the DEE while other WBCs showed less changes. It is concluded that blood components are so sensitive to DEE and do respond quicker to inhaled pollutants via changes in some components of WBC% but decrease in RBC% and the likelihood of blood clotting due to increase in blood platelets. These results indicate the acute toxic risks of the exposure to DEE of mechanics and technicians who work in vicinity of DEE sources or/and spend most daily hours in semi closed areas.
