The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were ba...The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were based on density functional theory. Many studies also used programs, such as VASP (Vienna Abinitio simulation package) and CPMD. The computational procedures used plane wave approximations. This needed studies with selection of K points and cutoff energy selection to assure convergence in energy calculations. Observations and analysis of papers published from 2006 to 2022 indicate that the cutoff energies were selected arbitrarily without any needed convergence studies. By selecting a published 2006 paper, this paper has clearly showed that an arbitrary selection of cutoff energy, such as 460 eV, is not in the range of, cutoff energies that assure convergence of energy calculations, with ab initio methods and have indicated correction procedures. .展开更多
Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of ...Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths.To increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites.Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,respectively.These results demonstrate the effectiveness of the azimuth cutoff compensation method.Based on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are discussed.The highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are used.The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.展开更多
Artificial chute cutoff can fundamentally eliminate the threat of flood caused by the meandering river,but it significantly changes its morphodynamic characteristics.Channel adjustments after cutoff are rapid,which ma...Artificial chute cutoff can fundamentally eliminate the threat of flood caused by the meandering river,but it significantly changes its morphodynamic characteristics.Channel adjustments after cutoff are rapid,which makes it difficult to study the interaction between river morphology and flow structure only through field measurement.However,numerical simulations can provide insights into the hydrodynamic characteristics after artificial chute cutoffs.In this study,both field measurement and numerical simulation are employed to investigate the flow structure and bed morphology caused by an artificial chute cutoff in Sipaikou area of the Upper Yellow River in 2018.The measured hydrological data provide boundary conditions and initial values for the numerical model.The field measurement results reveal that the concave bank of the study area is severely scoured up to 270 m after the artificial cutoff,and a 20 m deep scour hole and a 2.26 km long pool are formed at the entrance and near the left bank of the chute channel.The numerical simulation results of velocity at typical cross-sections are in good agreement with the measurement results.Flow separation and stagnation zones are observed near the right bank during the low flow conditions(discharge of at least 902 m^(3)/s),but this phenomenon is not seen during larger flow conditions(discharge exceeds 2000 m^(3)/s).Interestingly,flow recirculation zones are also found near the left and right banks of the scour hole.Further,a long flux belt is formed at the scour hole and the pool.Consequently,the impact of the bed topography on the hydrodynamic characteristics is relatively prominent when the discharge is small,while the impact on the river banks and river bed is more noticeable when the water discharge is large.In addition,high shear stress is observed near the left bank at the downstream of the studied area,which indicates that the left bank at the downstream is still being scoured.These results suggest that bank protection measures along the left bank are required to maintain the effectiveness of the artificial chute cutoff.展开更多
This paper demonstrates an intrinsic modulation of the cutoff wavelength in the spectra for solar selective absorbing coating based on high-entropy films.The(NiCuCrFeSi)N((NCCFS)N)films were deposited by a magnetron s...This paper demonstrates an intrinsic modulation of the cutoff wavelength in the spectra for solar selective absorbing coating based on high-entropy films.The(NiCuCrFeSi)N((NCCFS)N)films were deposited by a magnetron sputtering system.Rutherford backscattering spectroscopy analysis confirms the uniform composition and good homogeneity of these high-entropy films.The real and imaginary parts of the permittivity for the(NCCFS)N material are calculated on the basis of the reflectance spectral fitting results.A redshift cutoff wavelength of the reflectance spectrum with increasing nitrogen gas flow rate exists because of the different levels of dispersion when changing nitrogen content.To realize significant solar absorption,the film surface was reconstituted to match its impedance with air by designing a pyramid nanostructure metasurface.Compared with the absorptance of the as-deposited films,the designed metasurface obtains a significant improvement in solar absorption with the absorptance increasing from 0.74 to 0.99.The metasurfaces also show low mid-infrared emissions with thermal emittance that can be as low as 0.06.These results demonstrate a new idea in the design of solar selective absorbing surface with controllable absorptance and low infrared emission for high-efficiency photo-thermal conversion.展开更多
We theoretically investigate high-order harmonic generation by employing strong-field approximation(SFA) and present a new approach to the extension of the high-order harmonic cutoff frequency via an exploration of th...We theoretically investigate high-order harmonic generation by employing strong-field approximation(SFA) and present a new approach to the extension of the high-order harmonic cutoff frequency via an exploration of the dependence of high-order harmonic generation on the waveform of laser fields.The dependence is investigated via detailed analysis of the classical trajectories of the ionized electron moving in the continuum in the velocity-position plane.The classical trajectory consists of three sections(Acceleration Away,Deceleration Away,and Acceleration Back),and their relationship with the electron recollision energy is investigated.The analysis of classical trajectories indicates that,besides the final(Acceleration Back) section,the electron recollision energy also relies on the previous two sections.We simultaneously optimize the waveform in all three sections to increase the electron recollision energy,and an extension of the cutoff frequency up to Ip+20.26Up is presented with a theoretically synthesized waveform of the laser field.展开更多
Screening for elders at risk for depression is crucial for promoting mental health in later life. The present study investigates the cutoff score of a short form of the CES-D for screening of depressive symptoms in th...Screening for elders at risk for depression is crucial for promoting mental health in later life. The present study investigates the cutoff score of a short form of the CES-D for screening of depressive symptoms in the elderly population of Taiwan. This particular short form of CES-D is repeatedly used in the Taiwan Longitudinal Study on Aging (TLSA), a national survey of representative older adults in Taiwan, and is therefore referred to as the TLSA form. Data collected from five waves of TLSA were analyzed in this study. Participant responses repeatedly measured in 1989 and 1993 were used to identify a cutoff for the TLSA form of the CES-D with sensitivity and specificity using the cutoff of 4 on the Boston form of the CES-D as the criterion. Longitudinal data from the years 1996, 1999, and 2003 were used to validate the proposed cutoff by comparing the prevalence rates for depressive symptoms among older Taiwan Residents estimated from the identified cutoff and reported in previous studies. The score of 10 on the TLSA form of the CES-D was suggested, yielding a specificity of 0.93 and a sensitivity of approximately 0.96. The estimated prevalence rates for depressive symptoms among Taiwan Residents elders based on the suggested cutoff were between 18.9% and 23.7%, which are similar to previously reported rates. The cutoff score of 10 on the TLSA form of the CES-D is therefore recommended for screening depressive symptoms among older adults in Taiwan.展开更多
Objective To investigate the appropriate waist circumference (WC) cutoff points for central obesity in the middle-aged and elderly Beijing residents by the metabolic syndrome definition of the International Diabetes F...Objective To investigate the appropriate waist circumference (WC) cutoff points for central obesity in the middle-aged and elderly Beijing residents by the metabolic syndrome definition of the International Diabetes Federation (IDF). Methods A total of 2,344 Beijing residents aged ≥40 years were investigated. They answered questionnaires, received physical examinations, and underwent plasma glucose and lipid profile measurement. Those non-diabetic subjects underwent a 75g oral glucose tolerance test. All data were analyzed to calculate the appropriate WC cutoff points for central obesity reaching the diagonsis of MS. Results 1) Both in males and females, the triglyceride (TG), systolic blood pressure, diastolic blood pressure and fasting plasma glucose (FPG) increased linearly with WC, and the high density lipoprotein cholesterol (HDL-C) decreased linearly with WC (P<0.05). 2)The prevalence of elevated TG, reduced HDL-C, elevated blood pressure, elevated FBG, or ≥ 2 of these factors increased with WC (P<0.05). 3) Based on the receiver operating characteristic (ROC) curve analysis and Youden index, the WC values for central obesity and for detecting BMI ≥ 25 kg/m2 were about 90 cm for men and 80 cm for women. 4) The odds ratio for the presence of two or more metabolic risk factors increased abruptly in men with WC ≥ 90 cm and in women with WC ≥ 80 cm. Conclusions The appropriate WC cutoff point for central obesity was determined to be 90 cm for men and 80 cm for women in the middle-aged and elderly Beijing residents by the metabolic syndrome definition of IDF.展开更多
River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the mean...River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the meandering Lower Jingjiang section. River cutoff have been carried out in accordance with the evolution property of meandering rivers and these works have brought about expected benefits. It has also been noted that certain aspects in river cutoff had not been fully understood. River cutoff is a dynamic engineering. River channel evolution properties shall be fully understood so as to adroitly guide actions according to circumstances in cutoff works. In addition, river channel evolution observation and engineering effectiveness monitoring should be strengthened with a view to update the designs. The diversion canals for channel shortening are of great importance that will account for the success or failure of river cutoff works. The newly formed river channels and the river regime control works on the adjacent upper and lower reaches are guarantees for river cutoff works to be brought into play in the long run.展开更多
Objective:?To indentify Optimal cutoffs of grip strength for definition as weakness in the elderly. Methods: Our study population comprised 1317 subjects (mean ± SD age: 67.6 ± 6.0 years;44.3% men) from the ...Objective:?To indentify Optimal cutoffs of grip strength for definition as weakness in the elderly. Methods: Our study population comprised 1317 subjects (mean ± SD age: 67.6 ± 6.0 years;44.3% men) from the Hangu area of Tianjin, China. Data collection includes general physical examination, biochemical indicators and questionnaire. Mobility limitation was defined as a 4-m walking speed < 0.8 m/s and grip strength represents muscle strength. According to the ROC curve model, the cut-off point of grip strength was calculated, when mobility limitation was selected as the target variables. Results: According to the results of ROC curve, In man, grip strength is lower than 32.45 kg, the strength is weaker, Sensitivity is 79.7% and Specificity is 64.9%, the AUC is 0.764 (p < 0.001);In women, grip strength is lower than 18.20 kg, the strength is weaker, Sensitivity is 53.3% and Specificity is78.1%, the AUC is 0.703 (p < 0.001). Conclusions: Cut points for weakness derived from this large, diverse sample of older adults may be useful to identify populations who may benefit from interventions to improve muscle strength and function.展开更多
Impact of satellite elevation cutoff angle and position dilution of precision(PDOP)mask change on epoch-wise variance components of unmodeled effects that accompany relative Global Positioning System(GPS)positioning i...Impact of satellite elevation cutoff angle and position dilution of precision(PDOP)mask change on epoch-wise variance components of unmodeled effects that accompany relative Global Positioning System(GPS)positioning is presented herein.Data used for this study refer to the winter and summer periods of the years with minimal(2008)and maximal(2013)solar activity.These data were collected every 30 s in static mode,at two permanent GPS stations located in Montenegro,establishing a mediumdistance(116-km-long)baseline with a height difference of approximately 760 m between its endpoints.The study showed that changing satellite elevation cutoff angle,with a fixed PDOP mask,affects epochwise two-way nested ANOVA estimates of variances related to the‘far-field’multipath(considered as the nested factor herein)and the combined unmodeled effect of tropospheric and ionospheric refraction(considered as the nesting factor herein).However,changing of PDOP mask,with a fixed satellite elevation cutoff angle,doesn’t affect epoch-wise two-way nested ANOVA estimate of variance of the combined unmodeled effect of tropospheric and ionospheric refraction,but,generally,affects the estimate of variance of the‘far-field’multipath(possibly mixed with a part of a‘shorter-term’ionospheric refraction),which is especially pronounced for the summer period.It should also be noted that there is a significant influence of satellite elevation cutoff angle change on both epoch-wise horizontal and vertical position accuracy,only for the summer period,especially in the presence of maximal solar activity,while there is no significant impact of PDOP mask change on epoch-wise positional accuracy.展开更多
文摘The experimental research programs of 1950s, to understand the adsorption of CO on W surfaces, changed to ab initio studies in 2000s. The goals were to seek improved practical applications. Most of the studies were based on density functional theory. Many studies also used programs, such as VASP (Vienna Abinitio simulation package) and CPMD. The computational procedures used plane wave approximations. This needed studies with selection of K points and cutoff energy selection to assure convergence in energy calculations. Observations and analysis of papers published from 2006 to 2022 indicate that the cutoff energies were selected arbitrarily without any needed convergence studies. By selecting a published 2006 paper, this paper has clearly showed that an arbitrary selection of cutoff energy, such as 460 eV, is not in the range of, cutoff energies that assure convergence of energy calculations, with ab initio methods and have indicated correction procedures. .
基金the support of the National Natural Science Foundation of China(No.61931025)the National Key R&D Program of China(No.2017YFC1405600)。
文摘Synthetic aperture radars(SARs)encounter the azimuth cutoff problem when observing sea waves.Consequently,SARs can only capture the waves with wavelengths larger than the cutoff wavelength and lose the information of waves with smaller wavelengths.To increase the accuracy of SAR wave observations,this paper investigates an azimuth cutoff compensation method based on the simulated multiview SAR wave synchronization data obtained by the collaborative observation via networked satellites.Based on the simulated data and the equivalent multiview measured data from Sentinel-1 virtual networking,the method is verified and the cutoff wavelengths decrease by 16.40%and 14.00%.The biases of the inversion significant wave height with true values decrease by 0.04 m and 0.14 m,and the biases of the mean wave period decrease by 0.17 s and 0.22 s,respectively.These results demonstrate the effectiveness of the azimuth cutoff compensation method.Based on the azimuth cutoff compensation method,the multisatellite SAR networking mode for wave observations are discussed.The highest compensation effect is obtained when the combination of azimuth angle is(95°,115°,135°),the orbital intersection angle is(50°,50°),and three or four satellites are used.The study of the multisatellite networking mode in this paper can provide valuable references for the compensation of azimuth cutoff and the observation of waves by a multisatellite network.
基金This work was supported mainly by the National Natural Science Foundation of China(Grants No.11761005 and 11861003)partly supported by Key Research&Development Plan Projects of the Science and Technology Department of Ningxia Autonomous Region(Grant No.2019BEG03048)+1 种基金the Natural Science Foundation of Ningxia Province(Grants No.2021AAC03096,2021AAC03206 and 2020AAC03254)Science Research Project of Ningxia(Grant No.NGY2020009).
文摘Artificial chute cutoff can fundamentally eliminate the threat of flood caused by the meandering river,but it significantly changes its morphodynamic characteristics.Channel adjustments after cutoff are rapid,which makes it difficult to study the interaction between river morphology and flow structure only through field measurement.However,numerical simulations can provide insights into the hydrodynamic characteristics after artificial chute cutoffs.In this study,both field measurement and numerical simulation are employed to investigate the flow structure and bed morphology caused by an artificial chute cutoff in Sipaikou area of the Upper Yellow River in 2018.The measured hydrological data provide boundary conditions and initial values for the numerical model.The field measurement results reveal that the concave bank of the study area is severely scoured up to 270 m after the artificial cutoff,and a 20 m deep scour hole and a 2.26 km long pool are formed at the entrance and near the left bank of the chute channel.The numerical simulation results of velocity at typical cross-sections are in good agreement with the measurement results.Flow separation and stagnation zones are observed near the right bank during the low flow conditions(discharge of at least 902 m^(3)/s),but this phenomenon is not seen during larger flow conditions(discharge exceeds 2000 m^(3)/s).Interestingly,flow recirculation zones are also found near the left and right banks of the scour hole.Further,a long flux belt is formed at the scour hole and the pool.Consequently,the impact of the bed topography on the hydrodynamic characteristics is relatively prominent when the discharge is small,while the impact on the river banks and river bed is more noticeable when the water discharge is large.In addition,high shear stress is observed near the left bank at the downstream of the studied area,which indicates that the left bank at the downstream is still being scoured.These results suggest that bank protection measures along the left bank are required to maintain the effectiveness of the artificial chute cutoff.
基金the National Natural Science Foundation of China(Nos.51732001,U1832219,and 51972013)Beijing Natural Science Foundation(No.2182035)+1 种基金the Fundamental Research Funds for the Central Universities,the Program of China Scholarships Council(No.201806020161)the Academic Excellence Foundation of Beihang University(BUAA)for Ph.D.Students.
文摘This paper demonstrates an intrinsic modulation of the cutoff wavelength in the spectra for solar selective absorbing coating based on high-entropy films.The(NiCuCrFeSi)N((NCCFS)N)films were deposited by a magnetron sputtering system.Rutherford backscattering spectroscopy analysis confirms the uniform composition and good homogeneity of these high-entropy films.The real and imaginary parts of the permittivity for the(NCCFS)N material are calculated on the basis of the reflectance spectral fitting results.A redshift cutoff wavelength of the reflectance spectrum with increasing nitrogen gas flow rate exists because of the different levels of dispersion when changing nitrogen content.To realize significant solar absorption,the film surface was reconstituted to match its impedance with air by designing a pyramid nanostructure metasurface.Compared with the absorptance of the as-deposited films,the designed metasurface obtains a significant improvement in solar absorption with the absorptance increasing from 0.74 to 0.99.The metasurfaces also show low mid-infrared emissions with thermal emittance that can be as low as 0.06.These results demonstrate a new idea in the design of solar selective absorbing surface with controllable absorptance and low infrared emission for high-efficiency photo-thermal conversion.
基金supported by the National Basic Research Program of China (Grant No. 2010CB923102)the Special Prophase Project on the National Basic Research Program of China (Grant No. 2011CB311807)the National Natural Science Foundation of China (Grant No. 11074199)
文摘We theoretically investigate high-order harmonic generation by employing strong-field approximation(SFA) and present a new approach to the extension of the high-order harmonic cutoff frequency via an exploration of the dependence of high-order harmonic generation on the waveform of laser fields.The dependence is investigated via detailed analysis of the classical trajectories of the ionized electron moving in the continuum in the velocity-position plane.The classical trajectory consists of three sections(Acceleration Away,Deceleration Away,and Acceleration Back),and their relationship with the electron recollision energy is investigated.The analysis of classical trajectories indicates that,besides the final(Acceleration Back) section,the electron recollision energy also relies on the previous two sections.We simultaneously optimize the waveform in all three sections to increase the electron recollision energy,and an extension of the cutoff frequency up to Ip+20.26Up is presented with a theoretically synthesized waveform of the laser field.
文摘Screening for elders at risk for depression is crucial for promoting mental health in later life. The present study investigates the cutoff score of a short form of the CES-D for screening of depressive symptoms in the elderly population of Taiwan. This particular short form of CES-D is repeatedly used in the Taiwan Longitudinal Study on Aging (TLSA), a national survey of representative older adults in Taiwan, and is therefore referred to as the TLSA form. Data collected from five waves of TLSA were analyzed in this study. Participant responses repeatedly measured in 1989 and 1993 were used to identify a cutoff for the TLSA form of the CES-D with sensitivity and specificity using the cutoff of 4 on the Boston form of the CES-D as the criterion. Longitudinal data from the years 1996, 1999, and 2003 were used to validate the proposed cutoff by comparing the prevalence rates for depressive symptoms among older Taiwan Residents estimated from the identified cutoff and reported in previous studies. The score of 10 on the TLSA form of the CES-D was suggested, yielding a specificity of 0.93 and a sensitivity of approximately 0.96. The estimated prevalence rates for depressive symptoms among Taiwan Residents elders based on the suggested cutoff were between 18.9% and 23.7%, which are similar to previously reported rates. The cutoff score of 10 on the TLSA form of the CES-D is therefore recommended for screening depressive symptoms among older adults in Taiwan.
文摘Objective To investigate the appropriate waist circumference (WC) cutoff points for central obesity in the middle-aged and elderly Beijing residents by the metabolic syndrome definition of the International Diabetes Federation (IDF). Methods A total of 2,344 Beijing residents aged ≥40 years were investigated. They answered questionnaires, received physical examinations, and underwent plasma glucose and lipid profile measurement. Those non-diabetic subjects underwent a 75g oral glucose tolerance test. All data were analyzed to calculate the appropriate WC cutoff points for central obesity reaching the diagonsis of MS. Results 1) Both in males and females, the triglyceride (TG), systolic blood pressure, diastolic blood pressure and fasting plasma glucose (FPG) increased linearly with WC, and the high density lipoprotein cholesterol (HDL-C) decreased linearly with WC (P<0.05). 2)The prevalence of elevated TG, reduced HDL-C, elevated blood pressure, elevated FBG, or ≥ 2 of these factors increased with WC (P<0.05). 3) Based on the receiver operating characteristic (ROC) curve analysis and Youden index, the WC values for central obesity and for detecting BMI ≥ 25 kg/m2 were about 90 cm for men and 80 cm for women. 4) The odds ratio for the presence of two or more metabolic risk factors increased abruptly in men with WC ≥ 90 cm and in women with WC ≥ 80 cm. Conclusions The appropriate WC cutoff point for central obesity was determined to be 90 cm for men and 80 cm for women in the middle-aged and elderly Beijing residents by the metabolic syndrome definition of IDF.
文摘River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the meandering Lower Jingjiang section. River cutoff have been carried out in accordance with the evolution property of meandering rivers and these works have brought about expected benefits. It has also been noted that certain aspects in river cutoff had not been fully understood. River cutoff is a dynamic engineering. River channel evolution properties shall be fully understood so as to adroitly guide actions according to circumstances in cutoff works. In addition, river channel evolution observation and engineering effectiveness monitoring should be strengthened with a view to update the designs. The diversion canals for channel shortening are of great importance that will account for the success or failure of river cutoff works. The newly formed river channels and the river regime control works on the adjacent upper and lower reaches are guarantees for river cutoff works to be brought into play in the long run.
文摘Objective:?To indentify Optimal cutoffs of grip strength for definition as weakness in the elderly. Methods: Our study population comprised 1317 subjects (mean ± SD age: 67.6 ± 6.0 years;44.3% men) from the Hangu area of Tianjin, China. Data collection includes general physical examination, biochemical indicators and questionnaire. Mobility limitation was defined as a 4-m walking speed < 0.8 m/s and grip strength represents muscle strength. According to the ROC curve model, the cut-off point of grip strength was calculated, when mobility limitation was selected as the target variables. Results: According to the results of ROC curve, In man, grip strength is lower than 32.45 kg, the strength is weaker, Sensitivity is 79.7% and Specificity is 64.9%, the AUC is 0.764 (p < 0.001);In women, grip strength is lower than 18.20 kg, the strength is weaker, Sensitivity is 53.3% and Specificity is78.1%, the AUC is 0.703 (p < 0.001). Conclusions: Cut points for weakness derived from this large, diverse sample of older adults may be useful to identify populations who may benefit from interventions to improve muscle strength and function.
文摘Impact of satellite elevation cutoff angle and position dilution of precision(PDOP)mask change on epoch-wise variance components of unmodeled effects that accompany relative Global Positioning System(GPS)positioning is presented herein.Data used for this study refer to the winter and summer periods of the years with minimal(2008)and maximal(2013)solar activity.These data were collected every 30 s in static mode,at two permanent GPS stations located in Montenegro,establishing a mediumdistance(116-km-long)baseline with a height difference of approximately 760 m between its endpoints.The study showed that changing satellite elevation cutoff angle,with a fixed PDOP mask,affects epochwise two-way nested ANOVA estimates of variances related to the‘far-field’multipath(considered as the nested factor herein)and the combined unmodeled effect of tropospheric and ionospheric refraction(considered as the nesting factor herein).However,changing of PDOP mask,with a fixed satellite elevation cutoff angle,doesn’t affect epoch-wise two-way nested ANOVA estimate of variance of the combined unmodeled effect of tropospheric and ionospheric refraction,but,generally,affects the estimate of variance of the‘far-field’multipath(possibly mixed with a part of a‘shorter-term’ionospheric refraction),which is especially pronounced for the summer period.It should also be noted that there is a significant influence of satellite elevation cutoff angle change on both epoch-wise horizontal and vertical position accuracy,only for the summer period,especially in the presence of maximal solar activity,while there is no significant impact of PDOP mask change on epoch-wise positional accuracy.
