The total electric field(TEF) at ground level induced by high-voltage direct current(HVDC) overhead transmission lines is one of the important indexes for evaluating the lines' electromagnetic environment.Based on...The total electric field(TEF) at ground level induced by high-voltage direct current(HVDC) overhead transmission lines is one of the important indexes for evaluating the lines' electromagnetic environment.Based on analyzing the existing TEF sensors and the measurement principle of ion-current density,the influence from ions on TEF measurements is quantitively studied.The results show that the ions generated by the corona from a HVDC transmission line in operation cause errors in the measurement of TEF.This error is determined through analyzing the component of total measuring current on the filed mill's sensing electrode: if no appropriate approach taken,the maximum measurement error reaches up to 4.3%.Furthermore,a method that can eliminate such error,and hence improve the accuracy of TEF sensors is designed.展开更多
Ultra-high voltage(UHV)transmission lines are an important part of China’s power grid and are often surrounded by a complex electromagnetic environment.The ground total electric field is considered a main electromagn...Ultra-high voltage(UHV)transmission lines are an important part of China’s power grid and are often surrounded by a complex electromagnetic environment.The ground total electric field is considered a main electromagnetic environment indicator of UHV transmission lines and is currently employed for reliable long-term operation of the power grid.Yet,the accurate prediction of the ground total electric field remains a technical challenge.In this work,we collected the total electric field data from the Ningdong-Zhejiang±800 kV UHVDC transmission project,as of the Ling Shao line,and perform an outlier analysis of the total electric field data.We show that the Local Outlier Factor(LOF)elimination algorithm has a small average difference and overcomes the performance of Density-Based Spatial Clustering of Applications with Noise(DBSCAN)and Isolated Forest elimination algorithms.Moreover,the Stacking algorithm has been found to have superior prediction accuracy than a variety of similar prediction algorithms,including the traditional finite element.The low prediction error of the Stacking algorithm highlights the superior ability to accurately forecast the ground total electric field of UHVDC transmission lines.展开更多
With rapid growth of power demand, transmission capacity is also in urgent need of upgrading. In some cases, converting existing AC transmission lines to DC lines can Improve the transmission capacity and reduce the c...With rapid growth of power demand, transmission capacity is also in urgent need of upgrading. In some cases, converting existing AC transmission lines to DC lines can Improve the transmission capacity and reduce the construction investment. In this paper, the upstream finite element method was expanded to calculate the total electric field of same tower multi-circuit DC lines converted from double-circuit AC lines, and the validity of the algorithm was confirmed by experiments. Taking a DC line converted from a typical same tower 500 kV double-circuit AC transmission line as an example, the surface electric field and the ground total electric field in different pole conductor arrangement schemes were calculated and analyzed, and the critical height of pole conductors for DC lines in residential and non-residential area were determined. Then, the corridor width of DC and AC lines at critical height in residential and non-residential areas before and after AC-DC line transformation were compared. The results indicate that for DC lines converted from common 500 kV double-circuit AC lines, the ground total electric field can meet the requirements of corresponding standard with appropriate pole conductor arrangement schemes.展开更多
October oil field is one of the largest hydrocarbon-bearing fields which produces oil from the sand section of the Lower Miocene Asl Formation. Two marl (Asl Marl) and shale (Hawara Formation) sections of possible sou...October oil field is one of the largest hydrocarbon-bearing fields which produces oil from the sand section of the Lower Miocene Asl Formation. Two marl (Asl Marl) and shale (Hawara Formation) sections of possible source enrichment are detected above and below this oil sand section, respectively. This study aims to identify the content of the total organic carbon based on the density log and a combination technique of the resistivity and porosity logs (Δlog R Technique). The available geochemical analyses are used to calibrate the constants of the TOC and the level of maturity (LOM) used in the (Δlog R Technique). The geochemical-based LOM is found as 9.0 and the calibrated constants of the Asl Marl and Hawara Formation are found as 11.68, 3.88 and 8.77, 2.80, respectively. Fair to good TOC% content values (0.88 to 1.85) were recorded for Asl Marl section in the majority of the studied wells, while less than 0.5% is recorded for the Hawara Formation. The lateral distribution maps show that most of the TOC% enrichments are concentrated at central and eastern parts of the study area, providing a good source for the hydrocarbons encountered in the underlying Asl Sand section.展开更多
Purpose: To present a protocol of a dual-field rotational (DFR) total skin electron therapy (TSET) and to provide an assessment of clinical implementation, dosimetry properties, and skin dose evaluation. Methods and M...Purpose: To present a protocol of a dual-field rotational (DFR) total skin electron therapy (TSET) and to provide an assessment of clinical implementation, dosimetry properties, and skin dose evaluation. Methods and Materials: The DFR-TSET combined the Stanford 6-field and McGill rotational methods. Dual 6 MeV electron beams in high dose total skin electron mode were used for DFR-TSET on a commercial linac. Beam profiles and dosimetric properties were measured using solid phantoms. The dose rate at expanded source-to-surface distance (SSD) was a combination of static rate and rotational rate. In vivo dosimetry of patient skin was performed on patients’ skin using film, metal oxide semiconductor field-effect transistors (MOSFET), and optically stimulated luminescent dosimeters (OSLD). Results: Dual field rotational total skin electron therapy exhibited good (≤±10%) uniformity in the beam profiles in the vertical direction at an extended SSD of 332 cm with a gantry angulation of ±20˚ deviated from the horizontal direction. In-vivo measurements confirmed acceptable uniformity of the patients’ total body surfaces and revealed anatomically self-blocked or shielded areas where underdosing occurred. Conclusions: The clinical implementation of DFR-TSET effectively utilizes the special mode on a linac. This technique provides short beam-on times, uniform dose distribution, large treatment field, and reduced dose of x-ray contamination to the patients. In-vivo measurements indicate satisfactory delivery and dose uniformity of the prescribed dose. Electron boost fields are recommended at normal SSDs to address underdosed areas.展开更多
The Uranium-238 (<sup>238</sup>U), Thorium-232 (<sup>232</sup>Th) families and Potassium-40 (<sup>40</sup>K) are of terrestrial origin and contribute generally to an individual’s e...The Uranium-238 (<sup>238</sup>U), Thorium-232 (<sup>232</sup>Th) families and Potassium-40 (<sup>40</sup>K) are of terrestrial origin and contribute generally to an individual’s external exposure through our presence in this environment. They also contribute to the internal exposure through the ingestion of products and beverages such as water that are close to the earth. The aim of this work is to determine the committed effective dose or Total Indicative Dose (TID) due to gamma radioactivity of the borehole water from the Nord Riviera (NR) well field operated by the Côte d’Ivoire Water Distribution Company (SODECI) for the supply of drinking water to part of the population of Abidjan. In addition, the populations, with their habits, could use these borehole waters directly as drinking water. To this end, water samples from the seven (07) functional boreholes were collected and analyzed on a gamma spectrometry chain, equipped with an HPGe detector in the laboratory of the Radiation Protection Institute (RPI) of the GHANA Atomic Energy Commission (GAEC). The results of the specific activities of <sup>238</sup>U, <sup>232</sup>Th and <sup>40</sup>K obtained were transcribed into TID. As the natural radioactivity of the borehole water is high [1], the TIDs calculated from the activity results of the natural radionuclides<sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K vary for the seven boreholes from 0.150 to 0.166 mSv/yr with an average of 0.161 ± 0.034 mSv/yr. The TID of the control tower, where the borehole water is mixed and treated for household use, is equal to 0.136 ± 0.03 mSv/yr. The TIDs obtained are therefore all slightly greater than the WHO reference dose value of 0.1 mSv/yr. But all remain below the UNSCEAR reference dose of 0.29 mSv/yr.展开更多
[Objective]The research aimed to investigate the bioturbation effects of benthic fish Misgurnus anguillicaudatus on phosphorus dynamic in overlying water of paddy field,as well as to explore the bioturbation mechanism...[Objective]The research aimed to investigate the bioturbation effects of benthic fish Misgurnus anguillicaudatus on phosphorus dynamic in overlying water of paddy field,as well as to explore the bioturbation mechanism.[Method]Based on simulation experiment,the phosphorus contents in overlying water were analyzed comparatively with and without Misgurnus anguillicaudatus by the using of ion chromatography and spectrophotometry.[Result]The concentrations of total phosphorus(TP),dissolved total phosphorus(DTP)and particular phosphorus(PP)in bioturbation group had no significant differences with those in control group in initial stage of experiment,and became significantly higher than control group in middle and late stages of experiment(P<0.05). The PP/TP ratios in bioturbation group were bigger than those in control group,the increase of TP concentration in bioturbation group was mainly due to the increase of PP. The ratios of dissolved inorganic phosphorus(DIP) to DTP (DIP/DTP) were significantly bigger than those in control group in middle and late stages of experiment(P<0.05).[Conclusion]The benthic fish had bioturbation effects on phosphorus in overlying water of paddy field,which increased the available phosphorus for rice growth.展开更多
The proliferation of ultra-high voltage direct current(UHVDC)transmission technology has heightened regulatory oversight of electromagnetic fields around buildings.In conventional direct current(DC)line design,the pre...The proliferation of ultra-high voltage direct current(UHVDC)transmission technology has heightened regulatory oversight of electromagnetic fields around buildings.In conventional direct current(DC)line design,the presence of residential areas was typically not taken into account.GB 39220-2020 now requires environmental assessments for residential balconies and platforms.The impact of nearby residential buildings has to be taken into account during the design of DC lines,necessitating the calculation of the three-dimensional total electric field.This study introduces a parallel charge simulation method-flux tracing method to quickly calculate the 3D total electric field near buildings in proximity to UHVDC lines,which is crucial for engineering design and environmental assessment.The method significantly speeds up calculations,with a 4-15 times faster ratio using 16-32 threads.It also analyses how UHVDC line dimensions,distances to buildings and parameters of residential buildings affect the maximum electric field on platforms.By using regression analysis,the formula for predicting the maximum electric field is obtained,and the traditional calculation time is improved.This advancement provides efficient predictions and detailed 3D electric field distributions for engineering and environmental assessments.展开更多
In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for e...In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for extremely small and/or severe irregularly shaped fields. The air scatter data are involved directly or indirectly in obtaining the output. Despite the fact that extensive data have been published in many studies to provide a guide on the magnitude of output factor for clinical accelerators, there are very few data reviewed about output factor in-air or phantom for off-set fields. This study was aimed to investigate the impact of these conditions for small fields. This study was conducted in Elekta Synergy linear accelerator which produces 6 MV X-ray energy. The in-air output factor (Sc) has been measured by CC04 ion chamber with brass-alloy “build-up” cap and Dose-1 electrometer, and the total output (Scp) measurements were carried on at dose maximum depth in phantom by the same chamber and Thermoluminescence dosimeter (TLD) for 1 - 10 cm2 fields. The all measurements at center of isocenter and off-set fields at three directions (X2, Y1, Diagonal) were done. By decreasing field size from 10 to 2 cm2 at isocenter, the Sc value using CC04 was decreased to 5.4% and Scp using CC04 and TLD to 14.5% and 11% respectively. By increasing off-set value, the Sc and Scp values were increased in all directions comparing to central fields. The maximum increase was obtained in Y1 direction for Sc and Scp. TLD results for Scp is slightly higher than CC04. The dosimetric properties of small fields and their off-set should be evaluated and modelled appropriately in the treatment planning system to ensure accurate dose calculation in Intensity Modulated Radiation Treatment.展开更多
The 1^10^＋ 1^1（-1）^＋and 1^1（2）^＋ states of the helium atom in the magnetic field regime between 0 and 100 a.u. are studied using a full configuration-interaction （CI） approach. The total energies, derivatives...The 1^10^＋ 1^1（-1）^＋and 1^1（2）^＋ states of the helium atom in the magnetic field regime between 0 and 100 a.u. are studied using a full configuration-interaction （CI） approach. The total energies, derivatives of the total energy with respect to the magnetic field and ionisation energies are calculated with Hylleraas-like functions in spherical coordinates in low to intermediate fields and Hylleraas Caussian functions in cylindrical coordinates in intermediate to high fields, respectively. In intermediate fields, the total energies and ionisation energies are determined in terms of Hermite interpolation, based on the results obtained with the two above-mentioned basis functions. Calculations show that the current method can produce lower total energies and larger ionisation energies, and make the two ionisation energy curves obtained with the two above-mentioned basis functions join smoothly in intermediate fields. Comparisons are also made with previous works.展开更多
Using a full configuration-interaction method with Hylleraas-Gaussian basis function, this paper investigates the 1^10^＋, 1^1（-1）^＋ and 1^1（-2）6＋ states of the hydrogen negative ion in strong magnetic fields. T...Using a full configuration-interaction method with Hylleraas-Gaussian basis function, this paper investigates the 1^10^＋, 1^1（-1）^＋ and 1^1（-2）6＋ states of the hydrogen negative ion in strong magnetic fields. The total energies, electron detachment energies and derivatives of the total energy with respect to the magnetic field are presented as functions of magnetic field over a wide range of field strengths. Compared with the available theoretical data, the accuracy for the energies is enhanced significantly. The field regimes 3 〈 γ 〈 4 and 0.02 〈 γ 〈 0.05, in which the 1^1（-1）6＋ and 1^1（-2）^＋ states start to become bound, respectively, are also determined based on the calculated electron detachment energies.展开更多
Total Quality Management is not just an admirable phenomenon but it is any client’s right and can be done through contribution of the staff and the managers as well as the client’s of an organization. The purpose of...Total Quality Management is not just an admirable phenomenon but it is any client’s right and can be done through contribution of the staff and the managers as well as the client’s of an organization. The purpose of the present study is to investigate the feasibility of TQM model and the attitude of the managers of health field of Yazd medical sciences university towards it. The present study was a descriptive and analytical one which was cross-section ally conducted from 2010 to 2011. The population under study consisted of the managers of the unit of staff vice-chancellor for health and treatment, the managers of health system and centers of cities and also the managers of Yazd’s public hospitals. 64 people were chosen using the formula for calculating the number of samples. A questionnaire with 48 questions was used. The questionnaire’s validity was approved by the faculty members whose major is management and its reliability by using α-cronbach 87%. To analyze the data, the software SPSS V.17 was used. Scoring method was based on likert. The findings of the study show that, considering feasibility of TQM, there is a significant relation between the awareness and attitude of the managers of health and treatment field on one side and the variables, age and University degree, on the other side p = 0.001. Considering binary logistic regression and the results obtained in the form of inter and backward stepwise, the most important factors affecting the feasibility of TQM among the managers of health and treatment field are the level of awareness and attitude with the predicted accuracy 79.3% and 87.9% respectively.展开更多
基金Project supported by National Natural Science Foundation of China （61273165 51207005）.
文摘The total electric field(TEF) at ground level induced by high-voltage direct current(HVDC) overhead transmission lines is one of the important indexes for evaluating the lines' electromagnetic environment.Based on analyzing the existing TEF sensors and the measurement principle of ion-current density,the influence from ions on TEF measurements is quantitively studied.The results show that the ions generated by the corona from a HVDC transmission line in operation cause errors in the measurement of TEF.This error is determined through analyzing the component of total measuring current on the filed mill's sensing electrode: if no appropriate approach taken,the maximum measurement error reaches up to 4.3%.Furthermore,a method that can eliminate such error,and hence improve the accuracy of TEF sensors is designed.
基金funded by a science and technology project of State Grid Corporation of China“Comparative Analysis of Long-Term Measurement and Prediction of the Ground Synthetic Electric Field of±800 kV DC Transmission Line”(GYW11201907738)Paulo R.F.Rocha acknowledges the support and funding from the European Research Council(ERC)under the European Union’s Horizon 2020 Research and Innovation Program(Grant Agreement No.947897).
文摘Ultra-high voltage(UHV)transmission lines are an important part of China’s power grid and are often surrounded by a complex electromagnetic environment.The ground total electric field is considered a main electromagnetic environment indicator of UHV transmission lines and is currently employed for reliable long-term operation of the power grid.Yet,the accurate prediction of the ground total electric field remains a technical challenge.In this work,we collected the total electric field data from the Ningdong-Zhejiang±800 kV UHVDC transmission project,as of the Ling Shao line,and perform an outlier analysis of the total electric field data.We show that the Local Outlier Factor(LOF)elimination algorithm has a small average difference and overcomes the performance of Density-Based Spatial Clustering of Applications with Noise(DBSCAN)and Isolated Forest elimination algorithms.Moreover,the Stacking algorithm has been found to have superior prediction accuracy than a variety of similar prediction algorithms,including the traditional finite element.The low prediction error of the Stacking algorithm highlights the superior ability to accurately forecast the ground total electric field of UHVDC transmission lines.
文摘With rapid growth of power demand, transmission capacity is also in urgent need of upgrading. In some cases, converting existing AC transmission lines to DC lines can Improve the transmission capacity and reduce the construction investment. In this paper, the upstream finite element method was expanded to calculate the total electric field of same tower multi-circuit DC lines converted from double-circuit AC lines, and the validity of the algorithm was confirmed by experiments. Taking a DC line converted from a typical same tower 500 kV double-circuit AC transmission line as an example, the surface electric field and the ground total electric field in different pole conductor arrangement schemes were calculated and analyzed, and the critical height of pole conductors for DC lines in residential and non-residential area were determined. Then, the corridor width of DC and AC lines at critical height in residential and non-residential areas before and after AC-DC line transformation were compared. The results indicate that for DC lines converted from common 500 kV double-circuit AC lines, the ground total electric field can meet the requirements of corresponding standard with appropriate pole conductor arrangement schemes.
文摘October oil field is one of the largest hydrocarbon-bearing fields which produces oil from the sand section of the Lower Miocene Asl Formation. Two marl (Asl Marl) and shale (Hawara Formation) sections of possible source enrichment are detected above and below this oil sand section, respectively. This study aims to identify the content of the total organic carbon based on the density log and a combination technique of the resistivity and porosity logs (Δlog R Technique). The available geochemical analyses are used to calibrate the constants of the TOC and the level of maturity (LOM) used in the (Δlog R Technique). The geochemical-based LOM is found as 9.0 and the calibrated constants of the Asl Marl and Hawara Formation are found as 11.68, 3.88 and 8.77, 2.80, respectively. Fair to good TOC% content values (0.88 to 1.85) were recorded for Asl Marl section in the majority of the studied wells, while less than 0.5% is recorded for the Hawara Formation. The lateral distribution maps show that most of the TOC% enrichments are concentrated at central and eastern parts of the study area, providing a good source for the hydrocarbons encountered in the underlying Asl Sand section.
文摘Purpose: To present a protocol of a dual-field rotational (DFR) total skin electron therapy (TSET) and to provide an assessment of clinical implementation, dosimetry properties, and skin dose evaluation. Methods and Materials: The DFR-TSET combined the Stanford 6-field and McGill rotational methods. Dual 6 MeV electron beams in high dose total skin electron mode were used for DFR-TSET on a commercial linac. Beam profiles and dosimetric properties were measured using solid phantoms. The dose rate at expanded source-to-surface distance (SSD) was a combination of static rate and rotational rate. In vivo dosimetry of patient skin was performed on patients’ skin using film, metal oxide semiconductor field-effect transistors (MOSFET), and optically stimulated luminescent dosimeters (OSLD). Results: Dual field rotational total skin electron therapy exhibited good (≤±10%) uniformity in the beam profiles in the vertical direction at an extended SSD of 332 cm with a gantry angulation of ±20˚ deviated from the horizontal direction. In-vivo measurements confirmed acceptable uniformity of the patients’ total body surfaces and revealed anatomically self-blocked or shielded areas where underdosing occurred. Conclusions: The clinical implementation of DFR-TSET effectively utilizes the special mode on a linac. This technique provides short beam-on times, uniform dose distribution, large treatment field, and reduced dose of x-ray contamination to the patients. In-vivo measurements indicate satisfactory delivery and dose uniformity of the prescribed dose. Electron boost fields are recommended at normal SSDs to address underdosed areas.
文摘The Uranium-238 (<sup>238</sup>U), Thorium-232 (<sup>232</sup>Th) families and Potassium-40 (<sup>40</sup>K) are of terrestrial origin and contribute generally to an individual’s external exposure through our presence in this environment. They also contribute to the internal exposure through the ingestion of products and beverages such as water that are close to the earth. The aim of this work is to determine the committed effective dose or Total Indicative Dose (TID) due to gamma radioactivity of the borehole water from the Nord Riviera (NR) well field operated by the Côte d’Ivoire Water Distribution Company (SODECI) for the supply of drinking water to part of the population of Abidjan. In addition, the populations, with their habits, could use these borehole waters directly as drinking water. To this end, water samples from the seven (07) functional boreholes were collected and analyzed on a gamma spectrometry chain, equipped with an HPGe detector in the laboratory of the Radiation Protection Institute (RPI) of the GHANA Atomic Energy Commission (GAEC). The results of the specific activities of <sup>238</sup>U, <sup>232</sup>Th and <sup>40</sup>K obtained were transcribed into TID. As the natural radioactivity of the borehole water is high [1], the TIDs calculated from the activity results of the natural radionuclides<sup>238</sup>U, <sup>232</sup>Th, and <sup>40</sup>K vary for the seven boreholes from 0.150 to 0.166 mSv/yr with an average of 0.161 ± 0.034 mSv/yr. The TID of the control tower, where the borehole water is mixed and treated for household use, is equal to 0.136 ± 0.03 mSv/yr. The TIDs obtained are therefore all slightly greater than the WHO reference dose value of 0.1 mSv/yr. But all remain below the UNSCEAR reference dose of 0.29 mSv/yr.
基金Supported by Human Resources and Social Security Department Students Abroad Science and Technology Activities Preferred Foundation (Human and Social Council Issued 2008-86)Talent Development Fund Project in Jilin Province (Jilin 2007-259)+6 种基金Jilin Province Science and Technology Development Project (20060577 )Technology Project Jilin Provincial Ministry of Education (20094352006113 2007169)The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry ( 2005-546 )Science Foundation of Changchun Teachers University (2009002)Northeast Normal University Natural Science Foundation for Young Scholar (20050406)~~
文摘[Objective]The research aimed to investigate the bioturbation effects of benthic fish Misgurnus anguillicaudatus on phosphorus dynamic in overlying water of paddy field,as well as to explore the bioturbation mechanism.[Method]Based on simulation experiment,the phosphorus contents in overlying water were analyzed comparatively with and without Misgurnus anguillicaudatus by the using of ion chromatography and spectrophotometry.[Result]The concentrations of total phosphorus(TP),dissolved total phosphorus(DTP)and particular phosphorus(PP)in bioturbation group had no significant differences with those in control group in initial stage of experiment,and became significantly higher than control group in middle and late stages of experiment(P<0.05). The PP/TP ratios in bioturbation group were bigger than those in control group,the increase of TP concentration in bioturbation group was mainly due to the increase of PP. The ratios of dissolved inorganic phosphorus(DIP) to DTP (DIP/DTP) were significantly bigger than those in control group in middle and late stages of experiment(P<0.05).[Conclusion]The benthic fish had bioturbation effects on phosphorus in overlying water of paddy field,which increased the available phosphorus for rice growth.
基金Supported by State Grid Corporation of China(5200-202355390A-2-4-KJ).
文摘The proliferation of ultra-high voltage direct current(UHVDC)transmission technology has heightened regulatory oversight of electromagnetic fields around buildings.In conventional direct current(DC)line design,the presence of residential areas was typically not taken into account.GB 39220-2020 now requires environmental assessments for residential balconies and platforms.The impact of nearby residential buildings has to be taken into account during the design of DC lines,necessitating the calculation of the three-dimensional total electric field.This study introduces a parallel charge simulation method-flux tracing method to quickly calculate the 3D total electric field near buildings in proximity to UHVDC lines,which is crucial for engineering design and environmental assessment.The method significantly speeds up calculations,with a 4-15 times faster ratio using 16-32 threads.It also analyses how UHVDC line dimensions,distances to buildings and parameters of residential buildings affect the maximum electric field on platforms.By using regression analysis,the formula for predicting the maximum electric field is obtained,and the traditional calculation time is improved.This advancement provides efficient predictions and detailed 3D electric field distributions for engineering and environmental assessments.
文摘In intensity modulated radiation treatment (IMRT) planning, the use of asymmetrically collimated fields that are placed on central axis or its off-set is mostly required. Output is the main topic discussed today for extremely small and/or severe irregularly shaped fields. The air scatter data are involved directly or indirectly in obtaining the output. Despite the fact that extensive data have been published in many studies to provide a guide on the magnitude of output factor for clinical accelerators, there are very few data reviewed about output factor in-air or phantom for off-set fields. This study was aimed to investigate the impact of these conditions for small fields. This study was conducted in Elekta Synergy linear accelerator which produces 6 MV X-ray energy. The in-air output factor (Sc) has been measured by CC04 ion chamber with brass-alloy “build-up” cap and Dose-1 electrometer, and the total output (Scp) measurements were carried on at dose maximum depth in phantom by the same chamber and Thermoluminescence dosimeter (TLD) for 1 - 10 cm2 fields. The all measurements at center of isocenter and off-set fields at three directions (X2, Y1, Diagonal) were done. By decreasing field size from 10 to 2 cm2 at isocenter, the Sc value using CC04 was decreased to 5.4% and Scp using CC04 and TLD to 14.5% and 11% respectively. By increasing off-set value, the Sc and Scp values were increased in all directions comparing to central fields. The maximum increase was obtained in Y1 direction for Sc and Scp. TLD results for Scp is slightly higher than CC04. The dosimetric properties of small fields and their off-set should be evaluated and modelled appropriately in the treatment planning system to ensure accurate dose calculation in Intensity Modulated Radiation Treatment.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10874133)
文摘The 1^10^＋ 1^1（-1）^＋and 1^1（2）^＋ states of the helium atom in the magnetic field regime between 0 and 100 a.u. are studied using a full configuration-interaction （CI） approach. The total energies, derivatives of the total energy with respect to the magnetic field and ionisation energies are calculated with Hylleraas-like functions in spherical coordinates in low to intermediate fields and Hylleraas Caussian functions in cylindrical coordinates in intermediate to high fields, respectively. In intermediate fields, the total energies and ionisation energies are determined in terms of Hermite interpolation, based on the results obtained with the two above-mentioned basis functions. Calculations show that the current method can produce lower total energies and larger ionisation energies, and make the two ionisation energy curves obtained with the two above-mentioned basis functions join smoothly in intermediate fields. Comparisons are also made with previous works.
基金Project supported by the National Natural Science Foundation of China (Grant No. 10874133)
文摘Using a full configuration-interaction method with Hylleraas-Gaussian basis function, this paper investigates the 1^10^＋, 1^1（-1）^＋ and 1^1（-2）6＋ states of the hydrogen negative ion in strong magnetic fields. The total energies, electron detachment energies and derivatives of the total energy with respect to the magnetic field are presented as functions of magnetic field over a wide range of field strengths. Compared with the available theoretical data, the accuracy for the energies is enhanced significantly. The field regimes 3 〈 γ 〈 4 and 0.02 〈 γ 〈 0.05, in which the 1^1（-1）6＋ and 1^1（-2）^＋ states start to become bound, respectively, are also determined based on the calculated electron detachment energies.
文摘Total Quality Management is not just an admirable phenomenon but it is any client’s right and can be done through contribution of the staff and the managers as well as the client’s of an organization. The purpose of the present study is to investigate the feasibility of TQM model and the attitude of the managers of health field of Yazd medical sciences university towards it. The present study was a descriptive and analytical one which was cross-section ally conducted from 2010 to 2011. The population under study consisted of the managers of the unit of staff vice-chancellor for health and treatment, the managers of health system and centers of cities and also the managers of Yazd’s public hospitals. 64 people were chosen using the formula for calculating the number of samples. A questionnaire with 48 questions was used. The questionnaire’s validity was approved by the faculty members whose major is management and its reliability by using α-cronbach 87%. To analyze the data, the software SPSS V.17 was used. Scoring method was based on likert. The findings of the study show that, considering feasibility of TQM, there is a significant relation between the awareness and attitude of the managers of health and treatment field on one side and the variables, age and University degree, on the other side p = 0.001. Considering binary logistic regression and the results obtained in the form of inter and backward stepwise, the most important factors affecting the feasibility of TQM among the managers of health and treatment field are the level of awareness and attitude with the predicted accuracy 79.3% and 87.9% respectively.
