In this paper, we investigate the Cauchy problem for the nonlocal diffusion system with localized source ut = J*u-u + a(x)v~p, v_t = J*v-v + a(x)u~q. We first prove that the Fujita curve is(pq)_c*-= 1+max{p+1, q+1}bas...In this paper, we investigate the Cauchy problem for the nonlocal diffusion system with localized source ut = J*u-u + a(x)v~p, v_t = J*v-v + a(x)u~q. We first prove that the Fujita curve is(pq)_c*-= 1+max{p+1, q+1}based on whether there exist global solutions, thatis, if 1 < pq(pq)_c,then every nonnegative solution blows up in finite time, but for pq >(pq)_c,there exist both global and non-global solutions to the problem. Furthermore, we establish the secondary critical curve on the space-decay of initial value at infinity.展开更多
The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve,leading to quick-prediction of the parameters of single circular void.In this work,mode-shape ...The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve,leading to quick-prediction of the parameters of single circular void.In this work,mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed.A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the problem.In each iteration starting from each initial guess,the difference between the computationally obtained impedance curve and the target impedance curve has been reduced.This methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam.A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length,but not the precise location along beam-width.展开更多
The soil-water characteristic curve(SWCC) is widely used in the design and evaluation in the practice of geotechnical and geoenvironmental engineering such as the slope stability under the influence of environmental f...The soil-water characteristic curve(SWCC) is widely used in the design and evaluation in the practice of geotechnical and geoenvironmental engineering such as the slope stability under the influence of environmental factors. The SWCC has distinct features in the capillary and adsorption zones due to different physical mechanisms. Measurements of the SWCC are typically limited within the capillary zone(i.e., low suction range). It is cumbersome and time-consuming to measure the SWCC in the adsorption zone(i.e., high suction range). This study presents a simple method to predict the entire SWCC within both the capillary and adsorption zones, using measured data only from low suction range(e.g., from 0 to 500 kPa). Experimental studies were performed on a completely weathered granite residual soil to determine its entire SWCC from saturated to dry conditions. The resultant SWCC, along with the SWCC measurements of 14 soils reported in the literature, were used to validate the proposed method. The results indicate that the proposed method has good consistency with a wide array of measured data used in this study. The proposed method is easy to use as it only requires a simple parameter calibration for a commonly used SWCC model. It can be used to improve the reliability in the prediction of the SWCC over the entire suction range when measurements are limited within the low suction range.展开更多
BACKGROUND Enhanced recovery after surgery (ERAS) reduces hospitalization and complication following colorectal surgery. Whether the experience of multidisciplinary ERAS team affects patients’ outcomes is unknown. AI...BACKGROUND Enhanced recovery after surgery (ERAS) reduces hospitalization and complication following colorectal surgery. Whether the experience of multidisciplinary ERAS team affects patients’ outcomes is unknown. AIM To evaluate and establish a learning curve of ERAS program for open colorectal surgery. METHODS This was a review of prospectively collected database of 380 “unselected” patients undergoing elective “open” colectomy and/or proctectomy under ERAS protocol from 2011 (commencing ERAS application) to 2017 in a university hospital. Patients were divided into 5 chronological groups (76 cases per quintile). Surgical outcomes and ERAS compliance among quintiles were compared. Learning curves were calculated based on criteria of optimal recovery: defined as absence of major postoperative complications, discharge by postoperative day 5, and no 30-d readmission. RESULTS Hospitalization more than 5 d occurred in 22.6%(n = 86), major complication was present in 2.9%(n = 11) and 30-d readmission rate was 2.4%(n = 9) accounting for unsuccessful recovery of 25%(n = 95). Conversely, the overall rate of optimal recovery was 75%. The optimal recovery significantly increased from 57.9% in 1st quintile to 72.4%-85.5% in the following quintiles (P < 0.001). Average compliance with ERAS protocol gradually increased over the time - from 68.6% in 1st quintile to 75.5% in 5th quintile (P < 0.001). The application of preoperative counseling, nutrition support, goal-directed fluid therapy, O-ring wound protector and scheduled mobilization significantly increased over the study period.CONCLUSION A number of 76 colorectal operations are required for a multidisciplinary team to achieve a significantly higher rate of optimal recovery and high compliance with ERAS program for open colorectal surgery.展开更多
Effects of nitrogen-containing biodegradation enhancers(methyl diethanolamine oleate(MDEAO) and oleic diethanolamide(ODEA)) on the adsorption of n-hexadecane in soil were studied by laboratory batch experiments. The p...Effects of nitrogen-containing biodegradation enhancers(methyl diethanolamine oleate(MDEAO) and oleic diethanolamide(ODEA)) on the adsorption of n-hexadecane in soil were studied by laboratory batch experiments. The partition coefficients(Kd values) of n-hexadecane sorption in soil-water system and those partition coefficients normalized to organic matter(Koc values) were both determined. The adsorption isotherm curve of n-hexadecane in soil-water system was plotted. The measured results demonstrated that Koc values changed in the soil-water system with different enhancers but are relatively invariant for the soil at the same site. The Kd values rose with the increase of the organic matter content in different soil. The average values of Koc in the soil-water system with MDEAO, ODEA,and blank soil were 0.412, 0.252,and 0.309, respectively. The critical micelle concentration of ODEA and MDEAO was 0.7 mg/L and 1.9 mg/L, respectively,denoting that the solubilization capacity of ODEA was much stronger than MDEAO in the soil-water system. Consequently,the adsorption of MDEAO onto the solid surface increased the organic matter content in soil,which could make it more effective in enhancing the n-hexadecane adsorption. On the contrary, ODEA could inhibit the adsorption of n-hexadecane because of its less adsorption rate onto the soil particle surface and higher concentration in the soil-water system. According to the correlation coefficients, it was found that both the Henry linear and the Freundlich nonlinear isotherm sorption models were fitted to the data very well, however the Freundlich model was better than the Henry model.展开更多
Estimation of sedimentation in reservoirs helps in the management and design of the reservoir's useful capacity.This research was done on the Awash River basin at the Koka Dam Reservoir in Ethiopia.The method appl...Estimation of sedimentation in reservoirs helps in the management and design of the reservoir's useful capacity.This research was done on the Awash River basin at the Koka Dam Reservoir in Ethiopia.The method applied was the loose integration of the Soil and Water Assessment Tool(SWAT)model and Hydrologic Engineering Center-River Analysis System(HEC-RAS)model for the estimation of the sediment load reaching the reservoir.The SWAT model was used for the estimation of erosion at the catchment level,and the HEC-RAS model was applied to estimate the sediment transport in the river channel.The implemented method allows sedimentation in the floodplains and bed shear stress to be considered in the sediment modeling,which cannot be considered in the SWAT model.In addition,the river cross sectional properties and the hydrodynamic processes in the rivers were considered in the modeling process.The data used in this study are a combination of i)observed data collected by government agencies,ii)data available online in data repositories,and iii)data extracted from remote sensing in the Shuttle Radar Topographic Mission(SRTM)Digital Elevation Model(DEM).The calibration and validation of the SWAT model was done by using Sequential Uncertainty Fitting(SUIF-2)calibration and validation tools.The HEC-RAS model was calibrated by adjusting the roughness factor.The output from the integrated approaches gives better estimates of flow and sediment near the inlet to the reservoir,with coefficients of determination of 0.85 and 0.67,respectively,and Nash Sutcliffe coefficients of model fit efficiency of 0.90 and 0.62,respectively,for daily simulations.展开更多
Purpose:Acute burn resuscitation in initial 24 h remains a challenge to plastic surgeons.Though various formulae for fluid infusion are available but consensus is still lacking,resulting in under resuscitation or over...Purpose:Acute burn resuscitation in initial 24 h remains a challenge to plastic surgeons.Though various formulae for fluid infusion are available but consensus is still lacking,resulting in under resuscitation or over resuscitation.Parkland formula is widely used but recently its adequacy is questioned in studies.This study was conducted to see how closely the actual volume of fluid given in our center matches with that of calculated volume by Parkland formula.Methods:All patients admitted with more than 20% flame burn injury and within 8 h of incident were included in this study.Crystalloid solution for infusion was calculated as per Parkland formula;however,it was titrated according to the urine output.Data on fluid infusion were collected from patient's inpatient records and analyzed.Results:The study included a total of 90 patients,about 86.7% (n =78) of the patients received fluid less than the calculated Parkland formula.Rate of fluid administered over 24 h in our study was 3.149 mL/kg/ h.Mean hourly urine output was found to be 0.993 mL/kg/h.The mean difference between fluid administered and fluid calculated by Parkland formula was 3431.825 mL which was significant (p < 0.001).Conclusion:The study showed a significant difference in the fluid infused based on urine output and the fluid calculated by Parkland formula.This probably is because fluid infused based on end point of resuscitation was more physiological than fluid calculated based on formulae.展开更多
BACKGROUND Lenvatinib is one of the first-line tyrosine kinase inhibitors used for unresectable hepatocellular carcinoma (HCC). In the present study, we evaluated the potential of early changes in the time-intensity c...BACKGROUND Lenvatinib is one of the first-line tyrosine kinase inhibitors used for unresectable hepatocellular carcinoma (HCC). In the present study, we evaluated the potential of early changes in the time-intensity curve (TIC) of arterial phase on contrastenhanced ultrasound (CEUS) as early imaging biomarkers of lenvatinib efficacy. AIM To evaluate the potential of the early changes in the TIC of CEUS as early imaging biomarkers of lenvatinib efficacy in patients with unresectable HCC. METHODS We analyzed 20 consecutive patients with unresectable HCC treated with lenvatinib from March to November 2018. Tumor response at 8 wk was assessed by computed tomography using the modified Response Evaluation Criteria in Solid Tumors (mRECIST). CEUS was performed at baseline before treatment (Day 0) and on day 7 (Day 7), and the images were analyzed in the arterial phase for 20 seconds after the contrast agent arrived at the target tumor. Three perfusion parameters were extracted from the TICs: the slope of wash-in (Slope), time to peak (TTP) intensity, and the total area under the curve (AUC) during wash-in. The rate of change in the TIC parameters between Day 0 and Day 7 was compared between treatment responders and non-responders based on mRECIST. RESULTS The rate of change for all TIC parameters showed significant differences between the responders (n = 9) and non-responders (n = 11)(Slope, P = 0.025;TTP, P =0.004;and AUC, P = 0.0003). The area under the receiver operating curve values for slope, TTP, and AUC for the prediction of responders were 0.805, 0.869, and 0.939, respectively. CONCLUSION CEUS may be useful for the early prediction of tumor response to lenvatinib therapy in patients with unresectable HCC.展开更多
The hot deformation behavior and workability of a new reduced activation ferritic/martensitic steel named SIMP steel for accelerator-driven system were studied. The flow curve and its microstructure were studied at 90...The hot deformation behavior and workability of a new reduced activation ferritic/martensitic steel named SIMP steel for accelerator-driven system were studied. The flow curve and its microstructure were studied at 900-1200 ℃ and strain rate range of 0.001-10 s^-1. The results showed that the deformation behavior of the SIMP steel during hot compression could be manifested by the Zener-Hollomon parameter in an exponent-type equation. Based on the obtained constitutive equation, the calculated flow stresses were in agreement with the experimentally measured ones, and the average activity energies Qdrv and QHw for the initiation of dynamic recrystallization and the peak strain were calculated to be 476.1 kJ/mol and 462.7 kJ/mol, respectively. Furthermore, based on the processing maps and microstructure evolution, the optimum processing condition for the SIMP steel was determined to be 1050-1200 ℃/0.001-0.1s^-1.展开更多
The scaled boundary finite element method (SBFEM)is applied to the static analysis of two dimensional elasticity problem,boundary value problems domain with the domain completely described by a circular defining curve...The scaled boundary finite element method (SBFEM)is applied to the static analysis of two dimensional elasticity problem,boundary value problems domain with the domain completely described by a circular defining curve. The scaled boundary finite element equations is formulated within a general framework integrating the influence of the distributed body force,general boundary conditions,and bounded and unbounded domain.This paper investigates the possibility of using exact geometry to form the exact description of the circular defining curve and the standard finite element shape function to approximate the defining curve.Three linear elasticity problems are presented to verify the proposed method with the analytical solution.Numerical examples show the accuracy and efficiency of the proposed method,and the performance is found to be better than using standard linear element for the approximation defining curve on the scaled boundary method.展开更多
Density effects on the growth and self-thinning of Eucalyptus urophylla stands were examined for 7 years.The reciprocal equation of the competition-density(C–D)effect was used to describe the C–D effect in even-aged...Density effects on the growth and self-thinning of Eucalyptus urophylla stands were examined for 7 years.The reciprocal equation of the competition-density(C–D)effect was used to describe the C–D effect in even-aged pure stands of E.urophylla during course of self-thinning and showed a good fit to the data.The time trajectories of mean stem volume-density nearly paralleled the y-axis during early growth stages of stands,and then began to curve left.Finally,the mean stem volume-density trajectories of the low-,middle-and high-density stands tended to follow the self-thinning lines with slopes of-2.01,-1.90 and-1.99,respectively.With increasing physical time t,the biological timeτincreased rapidly during early growth stages and became slow gradually during later growth stages.Realized density-initial density curves tended to become more or less flat with increasing initial density,indicating the existence of an asymptotic value for density at a given time.The coefficientε,the reciprocal of which represents the asymptotic density at a given time,increased with increasing biological timeτ,indicating that the asymptotic density decreased with increasing stand age.Final yield Y(t)increased gradually with increasing stand age.展开更多
frequencies.The aim of this research was to determine the measures needed to protect the towns and villages from this type of damage.Daily total precipitation data for 1975–2010 were analysed,and rainfall-runoff mode...frequencies.The aim of this research was to determine the measures needed to protect the towns and villages from this type of damage.Daily total precipitation data for 1975–2010 were analysed,and rainfall-runoff models developed to estimate the potential yearly maximum discharge from each stream of sub-watersheds dominated by forests and/or agriculture.This was then calculated for different frequencies of the yearly maximum discharge.Flood analysis and mapping was modified via the one-dimensional Hydrologic Engineering Centers-River Analysis System software to produce potential maximum discharge and geometric data for Kaynasli Creek.As the main creek of the sub-watershed,its crosssection was shown to be insufficient and incapable of containing the maximum discharge at the 100-year frequency presumed for the watershed,and subsequently was seen as having a high level of casualty risk.It was concluded that the one dimensional model could be useful,but 2D models were more suitable for these types of watersheds.展开更多
基金the National Natural Science Foundation of China(Grant No.11301419)the Meritocracy Research Funds of China West Normal University(Grant No.17YC382).
文摘In this paper, we investigate the Cauchy problem for the nonlocal diffusion system with localized source ut = J*u-u + a(x)v~p, v_t = J*v-v + a(x)u~q. We first prove that the Fujita curve is(pq)_c*-= 1+max{p+1, q+1}based on whether there exist global solutions, thatis, if 1 < pq(pq)_c,then every nonnegative solution blows up in finite time, but for pq >(pq)_c,there exist both global and non-global solutions to the problem. Furthermore, we establish the secondary critical curve on the space-decay of initial value at infinity.
基金the financial support from NSFC(Grant No.11772234)and DAAD(IIT sandwich master program).
文摘The aim of current work is to improve the existing inverse methodology of void-detection based on a target impedance curve,leading to quick-prediction of the parameters of single circular void.In this work,mode-shape dependent shifting phenomenon of peaks of impedance curve with change in void location has been analyzed.A number of initial guesses followed by an iterative optimization algorithm based on univariate method has been used to solve the problem.In each iteration starting from each initial guess,the difference between the computationally obtained impedance curve and the target impedance curve has been reduced.This methodology has been extended to detect single circular metallic inclusion in 2D piezoelectric cantilever beam.A good accuracy level was observed for detection of flaw radius and flaw-location along beam-length,but not the precise location along beam-width.
基金the National Natural Science Fund of China(Grant Nos.51779191,51809199).
文摘The soil-water characteristic curve(SWCC) is widely used in the design and evaluation in the practice of geotechnical and geoenvironmental engineering such as the slope stability under the influence of environmental factors. The SWCC has distinct features in the capillary and adsorption zones due to different physical mechanisms. Measurements of the SWCC are typically limited within the capillary zone(i.e., low suction range). It is cumbersome and time-consuming to measure the SWCC in the adsorption zone(i.e., high suction range). This study presents a simple method to predict the entire SWCC within both the capillary and adsorption zones, using measured data only from low suction range(e.g., from 0 to 500 kPa). Experimental studies were performed on a completely weathered granite residual soil to determine its entire SWCC from saturated to dry conditions. The resultant SWCC, along with the SWCC measurements of 14 soils reported in the literature, were used to validate the proposed method. The results indicate that the proposed method has good consistency with a wide array of measured data used in this study. The proposed method is easy to use as it only requires a simple parameter calibration for a commonly used SWCC model. It can be used to improve the reliability in the prediction of the SWCC over the entire suction range when measurements are limited within the low suction range.
文摘BACKGROUND Enhanced recovery after surgery (ERAS) reduces hospitalization and complication following colorectal surgery. Whether the experience of multidisciplinary ERAS team affects patients’ outcomes is unknown. AIM To evaluate and establish a learning curve of ERAS program for open colorectal surgery. METHODS This was a review of prospectively collected database of 380 “unselected” patients undergoing elective “open” colectomy and/or proctectomy under ERAS protocol from 2011 (commencing ERAS application) to 2017 in a university hospital. Patients were divided into 5 chronological groups (76 cases per quintile). Surgical outcomes and ERAS compliance among quintiles were compared. Learning curves were calculated based on criteria of optimal recovery: defined as absence of major postoperative complications, discharge by postoperative day 5, and no 30-d readmission. RESULTS Hospitalization more than 5 d occurred in 22.6%(n = 86), major complication was present in 2.9%(n = 11) and 30-d readmission rate was 2.4%(n = 9) accounting for unsuccessful recovery of 25%(n = 95). Conversely, the overall rate of optimal recovery was 75%. The optimal recovery significantly increased from 57.9% in 1st quintile to 72.4%-85.5% in the following quintiles (P < 0.001). Average compliance with ERAS protocol gradually increased over the time - from 68.6% in 1st quintile to 75.5% in 5th quintile (P < 0.001). The application of preoperative counseling, nutrition support, goal-directed fluid therapy, O-ring wound protector and scheduled mobilization significantly increased over the study period.CONCLUSION A number of 76 colorectal operations are required for a multidisciplinary team to achieve a significantly higher rate of optimal recovery and high compliance with ERAS program for open colorectal surgery.
基金the financial support of the Science Foundation for Post-doctoral Researchers, Chongqing, China (project No. Xm2016078)the Natural Science Foundation of Chongqing (project No.CSTC2017jcyjAX0058).
文摘Effects of nitrogen-containing biodegradation enhancers(methyl diethanolamine oleate(MDEAO) and oleic diethanolamide(ODEA)) on the adsorption of n-hexadecane in soil were studied by laboratory batch experiments. The partition coefficients(Kd values) of n-hexadecane sorption in soil-water system and those partition coefficients normalized to organic matter(Koc values) were both determined. The adsorption isotherm curve of n-hexadecane in soil-water system was plotted. The measured results demonstrated that Koc values changed in the soil-water system with different enhancers but are relatively invariant for the soil at the same site. The Kd values rose with the increase of the organic matter content in different soil. The average values of Koc in the soil-water system with MDEAO, ODEA,and blank soil were 0.412, 0.252,and 0.309, respectively. The critical micelle concentration of ODEA and MDEAO was 0.7 mg/L and 1.9 mg/L, respectively,denoting that the solubilization capacity of ODEA was much stronger than MDEAO in the soil-water system. Consequently,the adsorption of MDEAO onto the solid surface increased the organic matter content in soil,which could make it more effective in enhancing the n-hexadecane adsorption. On the contrary, ODEA could inhibit the adsorption of n-hexadecane because of its less adsorption rate onto the soil particle surface and higher concentration in the soil-water system. According to the correlation coefficients, it was found that both the Henry linear and the Freundlich nonlinear isotherm sorption models were fitted to the data very well, however the Freundlich model was better than the Henry model.
基金the National Key Research and Development Program of China (Grant no. 2016YFC0402501) the National Natural Science Foundation of China (NSFC) (Grant no.51479071)+1 种基金the 111 Project (Grant nos. B12032 and B17015)the Priority Academic Program Development of Jiangsu Higher Education Institutions (Grant no.3014-SYS1401).
文摘Estimation of sedimentation in reservoirs helps in the management and design of the reservoir's useful capacity.This research was done on the Awash River basin at the Koka Dam Reservoir in Ethiopia.The method applied was the loose integration of the Soil and Water Assessment Tool(SWAT)model and Hydrologic Engineering Center-River Analysis System(HEC-RAS)model for the estimation of the sediment load reaching the reservoir.The SWAT model was used for the estimation of erosion at the catchment level,and the HEC-RAS model was applied to estimate the sediment transport in the river channel.The implemented method allows sedimentation in the floodplains and bed shear stress to be considered in the sediment modeling,which cannot be considered in the SWAT model.In addition,the river cross sectional properties and the hydrodynamic processes in the rivers were considered in the modeling process.The data used in this study are a combination of i)observed data collected by government agencies,ii)data available online in data repositories,and iii)data extracted from remote sensing in the Shuttle Radar Topographic Mission(SRTM)Digital Elevation Model(DEM).The calibration and validation of the SWAT model was done by using Sequential Uncertainty Fitting(SUIF-2)calibration and validation tools.The HEC-RAS model was calibrated by adjusting the roughness factor.The output from the integrated approaches gives better estimates of flow and sediment near the inlet to the reservoir,with coefficients of determination of 0.85 and 0.67,respectively,and Nash Sutcliffe coefficients of model fit efficiency of 0.90 and 0.62,respectively,for daily simulations.
文摘Purpose:Acute burn resuscitation in initial 24 h remains a challenge to plastic surgeons.Though various formulae for fluid infusion are available but consensus is still lacking,resulting in under resuscitation or over resuscitation.Parkland formula is widely used but recently its adequacy is questioned in studies.This study was conducted to see how closely the actual volume of fluid given in our center matches with that of calculated volume by Parkland formula.Methods:All patients admitted with more than 20% flame burn injury and within 8 h of incident were included in this study.Crystalloid solution for infusion was calculated as per Parkland formula;however,it was titrated according to the urine output.Data on fluid infusion were collected from patient's inpatient records and analyzed.Results:The study included a total of 90 patients,about 86.7% (n =78) of the patients received fluid less than the calculated Parkland formula.Rate of fluid administered over 24 h in our study was 3.149 mL/kg/ h.Mean hourly urine output was found to be 0.993 mL/kg/h.The mean difference between fluid administered and fluid calculated by Parkland formula was 3431.825 mL which was significant (p < 0.001).Conclusion:The study showed a significant difference in the fluid infused based on urine output and the fluid calculated by Parkland formula.This probably is because fluid infused based on end point of resuscitation was more physiological than fluid calculated based on formulae.
文摘BACKGROUND Lenvatinib is one of the first-line tyrosine kinase inhibitors used for unresectable hepatocellular carcinoma (HCC). In the present study, we evaluated the potential of early changes in the time-intensity curve (TIC) of arterial phase on contrastenhanced ultrasound (CEUS) as early imaging biomarkers of lenvatinib efficacy. AIM To evaluate the potential of the early changes in the TIC of CEUS as early imaging biomarkers of lenvatinib efficacy in patients with unresectable HCC. METHODS We analyzed 20 consecutive patients with unresectable HCC treated with lenvatinib from March to November 2018. Tumor response at 8 wk was assessed by computed tomography using the modified Response Evaluation Criteria in Solid Tumors (mRECIST). CEUS was performed at baseline before treatment (Day 0) and on day 7 (Day 7), and the images were analyzed in the arterial phase for 20 seconds after the contrast agent arrived at the target tumor. Three perfusion parameters were extracted from the TICs: the slope of wash-in (Slope), time to peak (TTP) intensity, and the total area under the curve (AUC) during wash-in. The rate of change in the TIC parameters between Day 0 and Day 7 was compared between treatment responders and non-responders based on mRECIST. RESULTS The rate of change for all TIC parameters showed significant differences between the responders (n = 9) and non-responders (n = 11)(Slope, P = 0.025;TTP, P =0.004;and AUC, P = 0.0003). The area under the receiver operating curve values for slope, TTP, and AUC for the prediction of responders were 0.805, 0.869, and 0.939, respectively. CONCLUSION CEUS may be useful for the early prediction of tumor response to lenvatinib therapy in patients with unresectable HCC.
基金the National Natural Science Foundation of China (No. 51874368)the Project of CAS Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences (No. 2018NMSAKF03).
文摘The hot deformation behavior and workability of a new reduced activation ferritic/martensitic steel named SIMP steel for accelerator-driven system were studied. The flow curve and its microstructure were studied at 900-1200 ℃ and strain rate range of 0.001-10 s^-1. The results showed that the deformation behavior of the SIMP steel during hot compression could be manifested by the Zener-Hollomon parameter in an exponent-type equation. Based on the obtained constitutive equation, the calculated flow stresses were in agreement with the experimentally measured ones, and the average activity energies Qdrv and QHw for the initiation of dynamic recrystallization and the peak strain were calculated to be 476.1 kJ/mol and 462.7 kJ/mol, respectively. Furthermore, based on the processing maps and microstructure evolution, the optimum processing condition for the SIMP steel was determined to be 1050-1200 ℃/0.001-0.1s^-1.
文摘The scaled boundary finite element method (SBFEM)is applied to the static analysis of two dimensional elasticity problem,boundary value problems domain with the domain completely described by a circular defining curve. The scaled boundary finite element equations is formulated within a general framework integrating the influence of the distributed body force,general boundary conditions,and bounded and unbounded domain.This paper investigates the possibility of using exact geometry to form the exact description of the circular defining curve and the standard finite element shape function to approximate the defining curve.Three linear elasticity problems are presented to verify the proposed method with the analytical solution.Numerical examples show the accuracy and efficiency of the proposed method,and the performance is found to be better than using standard linear element for the approximation defining curve on the scaled boundary method.
基金the Forestry Technology Popularization Demonstration Project of the Central Government of China(No.[2015]GDTK-07).
文摘Density effects on the growth and self-thinning of Eucalyptus urophylla stands were examined for 7 years.The reciprocal equation of the competition-density(C–D)effect was used to describe the C–D effect in even-aged pure stands of E.urophylla during course of self-thinning and showed a good fit to the data.The time trajectories of mean stem volume-density nearly paralleled the y-axis during early growth stages of stands,and then began to curve left.Finally,the mean stem volume-density trajectories of the low-,middle-and high-density stands tended to follow the self-thinning lines with slopes of-2.01,-1.90 and-1.99,respectively.With increasing physical time t,the biological timeτincreased rapidly during early growth stages and became slow gradually during later growth stages.Realized density-initial density curves tended to become more or less flat with increasing initial density,indicating the existence of an asymptotic value for density at a given time.The coefficientε,the reciprocal of which represents the asymptotic density at a given time,increased with increasing biological timeτ,indicating that the asymptotic density decreased with increasing stand age.Final yield Y(t)increased gradually with increasing stand age.
文摘frequencies.The aim of this research was to determine the measures needed to protect the towns and villages from this type of damage.Daily total precipitation data for 1975–2010 were analysed,and rainfall-runoff models developed to estimate the potential yearly maximum discharge from each stream of sub-watersheds dominated by forests and/or agriculture.This was then calculated for different frequencies of the yearly maximum discharge.Flood analysis and mapping was modified via the one-dimensional Hydrologic Engineering Centers-River Analysis System software to produce potential maximum discharge and geometric data for Kaynasli Creek.As the main creek of the sub-watershed,its crosssection was shown to be insufficient and incapable of containing the maximum discharge at the 100-year frequency presumed for the watershed,and subsequently was seen as having a high level of casualty risk.It was concluded that the one dimensional model could be useful,but 2D models were more suitable for these types of watersheds.