The upper part of the Fujia deposit was mined out by open-pit, and the lower part is being mined underground. The level pillar between open-pit and underground mine had a thickness of 24 m, a length of 300 m and a max...The upper part of the Fujia deposit was mined out by open-pit, and the lower part is being mined underground. The level pillar between open-pit and underground mine had a thickness of 24 m, a length of 300 m and a maximum width of 35 in. As the level pillar contained about 5.2 million ton ore of high nickel grade, it was necessary to recover the level pillar. Because of special need of safety, underhand heading cut-and-fill stoping method was used. For the first two layers of heading, the cemented fill materials were a mix of water and high-aluminum-content cement with silicate gelling agent; and for other heading layers, total tailings was added into the fill mix in order to reduce the cement consumption. Finally, the level pillar was recovered successfully.展开更多
Fusarium head blight (FHB) is a worldwide destructive disease of wheat in the warm, semi-humid or humid regions, especially serious in China. The disease not only causes significant losses in yield and reduces grain q...Fusarium head blight (FHB) is a worldwide destructive disease of wheat in the warm, semi-humid or humid regions, especially serious in China. The disease not only causes significant losses in yield and reduces grain quanlity, but also induces toxin to contaminated seeds, which is harmful to the healthy of human and livestocks, So it is important to control it. There are several methods to control Fusarium head blight (FHB). Such as using Crop rotation, Soil cultivation and Fertiliser, biological control, Fungicides control, transgenes, resistance to control Fusarium head blight (FHB). All of these methods gain some effect, but also exist their deficiency. Sometimes crop rotation had no significant effect on DON contamination of wheat grain, subsequent reductions in DON contamination were inconsistent when using Soil cultivation and Fertiliser, Unfortunately, under field conditions, the biological control achieved has been shown to be variable and in some tests has failed to give any control, The use of fungicides, however, have not been consistently effective in controlling FHB and in reducing DON formation, transgene-silencing at different generations is a problem to use transgenes, Information on location of QTL for FHB resistance should improve dramatically in the near future on resistance to control Fusarium head blight (FHB). Therefore, it is pressing to improve control methods, especially to DON.展开更多
AIM To evaluate the efficacy of endoscopic ultrasoundguided fine needle aspiration(EUS-FNA) of pancreatic head cancer when pushing(push method) or pulling the echoendoscope(pull method).METHODS Overall, 566 pancreatic...AIM To evaluate the efficacy of endoscopic ultrasoundguided fine needle aspiration(EUS-FNA) of pancreatic head cancer when pushing(push method) or pulling the echoendoscope(pull method).METHODS Overall, 566 pancreatic cancer patients had their first EUS-FNA between February 2001 and December 2017. Among them, 201 who underwent EUS-FNA for pancreatic head lesions were included in this study. EUS-FNA was performed by the push method in 85 patients, the pull method in 101 patients and both the push and pull methods in 15 patients. After propensity score matching(age, sex, tumor diameter, and FNA needle), 85 patients each were stratified into the push and pull groups. Patient characteristics and EUSFNA-related factors were compared between the two groups.RESULTS Patient characteristics were not significantly different between the two groups. The distance to lesion was significantly longer in the push group than in the pull group(13.9 ± 4.9 mm vs 7.0 ± 4.9 mm, P < 0.01). The push method was a significant factor influencing the distance to lesion(≥ median 10 mm)(P < 0.01). Additionally, tumor diameter ≥ 25 mm(OR = 1.91, 95%CI: 1.02-3.58, P = 0.043) and the push method(OR = 1.91, 95%CI: 1.03-3.55, P = 0.04) were significant factors contributing to the histological diagnosis of malignancy.CONCLUSION The pull method shortened the distance between the endoscope and the lesion and facilitated EUS-FNA of pancreatic head cancer. The push method contributed to the histological diagnosis of pancreatic head cancer using EUS-FNA specimens.展开更多
In this paper we present the Projection Based Interpolation (PBI) technique for construction of continuous approximation of MRI scan data of the human head. We utilize the result of the PBI algorithm to perform three ...In this paper we present the Projection Based Interpolation (PBI) technique for construction of continuous approximation of MRI scan data of the human head. We utilize the result of the PBI algorithm to perform three dimensional (3D) Finite Element Method (FEM) simulations of the acoustics of the human head. The computational problem is a multi-physics problem modeled as acoustics coupled with linear elasticity. The computational grid contains tetrahedral finite elements with the number of equations and polynomial orders of approximation varying locally on finite element edges, faces, and interiors. We utilize our own out-of-core parallel direct solver for the solution of this multi-physics problem. The solver minimizes the memory usage by dumping out all local systems from all nodes of the entire elimination tree during the elimination phase.展开更多
Boiler pressure vessels play an important role in various industry applications, but due to the influence of many factors, make the safety problem of pressure vessels more and more prominent. In this environment, it i...Boiler pressure vessels play an important role in various industry applications, but due to the influence of many factors, make the safety problem of pressure vessels more and more prominent. In this environment, it is very necessary to strengthen the pressing technology of boiler and pressure vessel. Based on this, this paper focuses on the manufacturing methods of boiler and pressure vessel heads, which can provide the corresponding basis for head technology research and development as a reference, and effectively promote the production quality of related products to meet the relevant standards.展开更多
As an improved guidance method,the attitude head pursuit guidance （AHPG） law enables the attitude pursuit guidance （APG） law to be more suited to transition guidance of air-to-ground missiles. By adding a head ang...As an improved guidance method,the attitude head pursuit guidance （AHPG） law enables the attitude pursuit guidance （APG） law to be more suited to transition guidance of air-to-ground missiles. By adding a head angle into the attitude angle of APG,AHPG directs the missile axis onto the line of sight （LOS）. The maximum range trajectory simulation shows that the elevator deflection angle reaches the saturated value of 10° at the outset and the impact angle is less than 60° when APG is used as transi-tion guidance law. However,the elevator deflection angle on the whole trajectory is reduced to under 5° and the impact angle increased to over 60° when AHPG is used. The formulae to calculate head angles are derived for different target distributions. The simulation of multiple trajectories shows that with the help of the formulae based on AHPG law,the same performance could be achieved.展开更多
AIM To investigate the role of tumor necrosisfactor(TNF)in lung injury during acutenecrotizing pancreatitis(ANP),and thetherapeutic effect of'Tong Xia'purgativemethod in minimizing the severity of lung injury....AIM To investigate the role of tumor necrosisfactor(TNF)in lung injury during acutenecrotizing pancreatitis(ANP),and thetherapeutic effect of'Tong Xia'purgativemethod in minimizing the severity of lung injury.METHODS Fourteen canines were randomlydivided into 3 groups:the'Tong Xia'treatmentgroup(n = 5)using Dachengqitang;salinecontrol group(n = 5),and the sham operationgroup(n = 4).TNF activity in serum and inbronchoalveolar lavage fluid(BALF),the serumendotoxin levels were measured,and theseverity of lung injury evaluated.RESULTS Elevation of TNF activity was moreprominent in BALF than in serum.TNF activity inserum at 6 and 12 hours and in BALI:wassignificantly decreased in the'Tong Xia'treatment group than in the saline control one(q=21.11,q=12.07,q=9.03,respectively,P【0.01)and the lung injury was significantlyalleviated at 12 hours as compared with that inthe saline group,manifested as amelioration otthe lung wet/ dry weight ratio,decrease inprotein concentration and neutrophils count inBALF,and improvement of pulmonaryinflammatory changes.A positive correlationwas demonstrated between serum TNF activity and endotoxin level.CONCLUSION Hypersecretion of TNF is shownto be one of the major causes of lung injuryduring ANP;'Tong Xia'purgative method couldalleviate the degree of lung injury mediated byTNF.展开更多
Objective: To compare maternal and fetal outcome associated with two methods Reverse breech extraction versus Head pushing to deliver the impacted fetal head in advanced labor requiring emergency Cesarean section. Met...Objective: To compare maternal and fetal outcome associated with two methods Reverse breech extraction versus Head pushing to deliver the impacted fetal head in advanced labor requiring emergency Cesarean section. Method: A prospective comparative study was conducted on 80 pregnant women at term with cephalic presentation in advanced labour, requiring emergency Cesarean Section. Reverse breech extraction technique (pull method) was used in 40 cases (group I) and pushing the head up through the vagina (“push” method) was tried in (group II) 40 cases. The maternal outcome was assessed by extension of the uterine Incision, bladder injury, intra and postoperative blood transfusion, Postpartum hemorrhage, wound infection and duration of hospital stay. Fetal outcome was Apgar score and admission to neonatal intensive care unit. Results: Extension of the uterine incision was significantly lower in women undergoing reverse breech extraction compared to cephalic delivery (20% versus 50%;p = 0.001). The mean operative time (pull group) was lower than that in the (push group) 59.7 ± 4.2, versus 75.2 ± 6.1 p = 0.001 and blood loss was significantly lower in the (pull group) than that in the (push group) 878 ± 67 ml, versus 1321 ± 57 ml, p = 0.001. No significant difference between groups regarding maternal and neonatal outcome. Conclusion: Reverse breech extraction (pull) is safer than pushing head up through vagina (push) for delivery of a deeply impacted fetal head in advanced labour sensitizing emergency Cesarean Section and is associated with the least maternal complications.展开更多
The 25 years＇ production and application have proved that vermicular graphite iron cylinder heads with vermicularity ≥50% satisfy the machinability and performance demand of diesel engine. The method, in which using...The 25 years＇ production and application have proved that vermicular graphite iron cylinder heads with vermicularity ≥50% satisfy the machinability and performance demand of diesel engine. The method, in which using cupola-induction furnace duplex melting and pour-over process with rare earth-ferrosilicon or rare earthsilicon compound as vermJcularizing alloy plus rare earth-magnesium-ferrosilicon as stirring alloy, is an optimal vermicularizing process for obtaining satisfied vermicularity. Using top kiss risers, enlarging kissing areas and expanding covering width and making ingates to freeze earlier are the effective measures to eliminate shrinkage, blowhole and oxide inclusions in the vermicular graphite iron cylinder heads.展开更多
Objective To probe methods and therapeutic effects of Head Acupuncture on ischemic stroke. Methods One hundred and twelve cases were randomly divided into observation group (head acupuncture group) and control group (...Objective To probe methods and therapeutic effects of Head Acupuncture on ischemic stroke. Methods One hundred and twelve cases were randomly divided into observation group (head acupuncture group) and control group (body acupuncture group). After treatment of 28 days, changes of linguistic function and paralysis level of limbs before and after treatment were investigated. Results The total effective rate was 96.6% in the observation group and 90.7%, in the control group, with a significant difference between the two groups (P<0.05). Conclusion The electroacupuncture head point-through-point by penetrating two point therapy is one of effective methods for ischemic stroke.展开更多
In this paper,using the reductive perturbation method combined with the PLK method and two-parameter expansions,we treat the problem of head-on collision between two solitary waves described by the generalized Kortewe...In this paper,using the reductive perturbation method combined with the PLK method and two-parameter expansions,we treat the problem of head-on collision between two solitary waves described by the generalized Korteweg-de Vries equation (the gKdV equation) and obtain its second-order approximate solution.The results show that after the collision,the gKdV solitary waves preserve their profiles and during the collision,the maximum amplitute is the linear superposition of two maximum amplitudes of the impinging solitary waves.展开更多
In this study, finite difference method is used to solve the equations that govern groundwater flow to obtain flow rates, flow direction and hydraulic heads through an aquifer. The aim therefore is to discuss the prin...In this study, finite difference method is used to solve the equations that govern groundwater flow to obtain flow rates, flow direction and hydraulic heads through an aquifer. The aim therefore is to discuss the principles of Finite Difference Method and its applications in groundwater modelling. To achieve this, a rectangular grid is overlain an aquifer in order to obtain an exact solution. Initial and boundary conditions are then determined. By discretizing the system into grids and cells that are small compared to the entire aquifer, exact solutions are obtained. A flow chart of the computational algorithm for particle tracking is also developed. Results show that under a steady-state flow with no recharge, pathlines coincide with streamlines. It is also found that the accuracy of the numerical solution by Finite Difference Method is largely dependent on initial particle distribution and number of particles assigned to a cell. It is therefore concluded that Finite Difference Method can be used to predict the future direction of flow and particle location within a simulation domain.展开更多
The sarcoma structure of goldfish was first analyzed by frozen section technique. The present study revealed the alkaline and acid phosphatase distribution in the head sarcoma of goldfish. And the histochemical staini...The sarcoma structure of goldfish was first analyzed by frozen section technique. The present study revealed the alkaline and acid phosphatase distribution in the head sarcoma of goldfish. And the histochemical staining in situ by calcium-cobalt method and lead nitrate method displayed a large amount of alkaline and acid phosphatases in the head sarcoma, with higher enzyme activity. The alkaline and acid phosphatases belong to hydrolases, which are widely present in various tissues. The results showed that the activity of external sarcoma is similar to the middle one, while there was more alkaline phosphatase near to the tissue sarcoma under the goldfish scales. And they have the strong activity. The study will lay the theoretical basis on enhancing the ornamental value of goldfish.展开更多
In this paper, we present the Projection Based Interpolation (PBI) technique for construction of continuous approximation of MRI scan data of the human head. We utilize the result of the PBI algorithm to perform three...In this paper, we present the Projection Based Interpolation (PBI) technique for construction of continuous approximation of MRI scan data of the human head. We utilize the result of the PBI algorithm to perform three-dimensional (3D) Finite Element Method (FEM) simulations of the heating of the human head induced by cell phone. In particular, we utilize the Pennes equation to describe the bioheat transfer with the right hand side representing the heat generated by cell phone. We utilize our own non-stationary time dependent multi-thread parallel direct solver for the solution of this computational problem. From our numerical results it follows that 15 minutes (1000 seconds) exposure to the cell phone radiation implies up to 2 degrees Celsius increase of the temperature of the brain in the range close to the cell phone.展开更多
Thin-walled torispherical heads under internal pressure can fail by plastic buckling because of compressive circumferential stresses in the head knuckle.However,existing formulas still have limitations,such as complic...Thin-walled torispherical heads under internal pressure can fail by plastic buckling because of compressive circumferential stresses in the head knuckle.However,existing formulas still have limitations,such as complicated expressions and low accuracy,in determining buckling pressure.In this paper,we propose a new formula for calculating the buckling pressure of torispherical heads based on elastic-plastic analysis and experimental results.First,a finite element(FE)method based on the arc-length method is established to calculate the plastic buckling pressure of torispherical heads,considering the effects of material strain hardening and geometrical nonlinearity.The buckling pressure results calculated by the FE method in this paper have good consistency with those of BOSOR5,which is a program for calculating the elastic-plastic bifurcation buckling pressure based on the finite difference energy method.Second,the effects of geometric parameters,material parameters,and restraint form of head edge on buckling pressure are investigated.Third,a new formula for calculating plastic buckling pressure is developed by fitting the curve of FE results and introducing a reduction factor determined from experimental data.Finally,based on the experimental results,we compare the predictions of the new formula with those of existing formulas.It is shown that the new formula has a higher accuracy than the existing ones.展开更多
文摘The upper part of the Fujia deposit was mined out by open-pit, and the lower part is being mined underground. The level pillar between open-pit and underground mine had a thickness of 24 m, a length of 300 m and a maximum width of 35 in. As the level pillar contained about 5.2 million ton ore of high nickel grade, it was necessary to recover the level pillar. Because of special need of safety, underhand heading cut-and-fill stoping method was used. For the first two layers of heading, the cemented fill materials were a mix of water and high-aluminum-content cement with silicate gelling agent; and for other heading layers, total tailings was added into the fill mix in order to reduce the cement consumption. Finally, the level pillar was recovered successfully.
文摘Fusarium head blight (FHB) is a worldwide destructive disease of wheat in the warm, semi-humid or humid regions, especially serious in China. The disease not only causes significant losses in yield and reduces grain quanlity, but also induces toxin to contaminated seeds, which is harmful to the healthy of human and livestocks, So it is important to control it. There are several methods to control Fusarium head blight (FHB). Such as using Crop rotation, Soil cultivation and Fertiliser, biological control, Fungicides control, transgenes, resistance to control Fusarium head blight (FHB). All of these methods gain some effect, but also exist their deficiency. Sometimes crop rotation had no significant effect on DON contamination of wheat grain, subsequent reductions in DON contamination were inconsistent when using Soil cultivation and Fertiliser, Unfortunately, under field conditions, the biological control achieved has been shown to be variable and in some tests has failed to give any control, The use of fungicides, however, have not been consistently effective in controlling FHB and in reducing DON formation, transgene-silencing at different generations is a problem to use transgenes, Information on location of QTL for FHB resistance should improve dramatically in the near future on resistance to control Fusarium head blight (FHB). Therefore, it is pressing to improve control methods, especially to DON.
文摘AIM To evaluate the efficacy of endoscopic ultrasoundguided fine needle aspiration(EUS-FNA) of pancreatic head cancer when pushing(push method) or pulling the echoendoscope(pull method).METHODS Overall, 566 pancreatic cancer patients had their first EUS-FNA between February 2001 and December 2017. Among them, 201 who underwent EUS-FNA for pancreatic head lesions were included in this study. EUS-FNA was performed by the push method in 85 patients, the pull method in 101 patients and both the push and pull methods in 15 patients. After propensity score matching(age, sex, tumor diameter, and FNA needle), 85 patients each were stratified into the push and pull groups. Patient characteristics and EUSFNA-related factors were compared between the two groups.RESULTS Patient characteristics were not significantly different between the two groups. The distance to lesion was significantly longer in the push group than in the pull group(13.9 ± 4.9 mm vs 7.0 ± 4.9 mm, P < 0.01). The push method was a significant factor influencing the distance to lesion(≥ median 10 mm)(P < 0.01). Additionally, tumor diameter ≥ 25 mm(OR = 1.91, 95%CI: 1.02-3.58, P = 0.043) and the push method(OR = 1.91, 95%CI: 1.03-3.55, P = 0.04) were significant factors contributing to the histological diagnosis of malignancy.CONCLUSION The pull method shortened the distance between the endoscope and the lesion and facilitated EUS-FNA of pancreatic head cancer. The push method contributed to the histological diagnosis of pancreatic head cancer using EUS-FNA specimens.
文摘In this paper we present the Projection Based Interpolation (PBI) technique for construction of continuous approximation of MRI scan data of the human head. We utilize the result of the PBI algorithm to perform three dimensional (3D) Finite Element Method (FEM) simulations of the acoustics of the human head. The computational problem is a multi-physics problem modeled as acoustics coupled with linear elasticity. The computational grid contains tetrahedral finite elements with the number of equations and polynomial orders of approximation varying locally on finite element edges, faces, and interiors. We utilize our own out-of-core parallel direct solver for the solution of this multi-physics problem. The solver minimizes the memory usage by dumping out all local systems from all nodes of the entire elimination tree during the elimination phase.
文摘Boiler pressure vessels play an important role in various industry applications, but due to the influence of many factors, make the safety problem of pressure vessels more and more prominent. In this environment, it is very necessary to strengthen the pressing technology of boiler and pressure vessel. Based on this, this paper focuses on the manufacturing methods of boiler and pressure vessel heads, which can provide the corresponding basis for head technology research and development as a reference, and effectively promote the production quality of related products to meet the relevant standards.
文摘As an improved guidance method,the attitude head pursuit guidance （AHPG） law enables the attitude pursuit guidance （APG） law to be more suited to transition guidance of air-to-ground missiles. By adding a head angle into the attitude angle of APG,AHPG directs the missile axis onto the line of sight （LOS）. The maximum range trajectory simulation shows that the elevator deflection angle reaches the saturated value of 10° at the outset and the impact angle is less than 60° when APG is used as transi-tion guidance law. However,the elevator deflection angle on the whole trajectory is reduced to under 5° and the impact angle increased to over 60° when AHPG is used. The formulae to calculate head angles are derived for different target distributions. The simulation of multiple trajectories shows that with the help of the formulae based on AHPG law,the same performance could be achieved.
基金the"8th 5-year Plan"of National Administration Bureau of Traditional Chinese Medicine and Pharmacy,No.H09301
文摘AIM To investigate the role of tumor necrosisfactor(TNF)in lung injury during acutenecrotizing pancreatitis(ANP),and thetherapeutic effect of'Tong Xia'purgativemethod in minimizing the severity of lung injury.METHODS Fourteen canines were randomlydivided into 3 groups:the'Tong Xia'treatmentgroup(n = 5)using Dachengqitang;salinecontrol group(n = 5),and the sham operationgroup(n = 4).TNF activity in serum and inbronchoalveolar lavage fluid(BALF),the serumendotoxin levels were measured,and theseverity of lung injury evaluated.RESULTS Elevation of TNF activity was moreprominent in BALF than in serum.TNF activity inserum at 6 and 12 hours and in BALI:wassignificantly decreased in the'Tong Xia'treatment group than in the saline control one(q=21.11,q=12.07,q=9.03,respectively,P【0.01)and the lung injury was significantlyalleviated at 12 hours as compared with that inthe saline group,manifested as amelioration otthe lung wet/ dry weight ratio,decrease inprotein concentration and neutrophils count inBALF,and improvement of pulmonaryinflammatory changes.A positive correlationwas demonstrated between serum TNF activity and endotoxin level.CONCLUSION Hypersecretion of TNF is shownto be one of the major causes of lung injuryduring ANP;'Tong Xia'purgative method couldalleviate the degree of lung injury mediated byTNF.
文摘Objective: To compare maternal and fetal outcome associated with two methods Reverse breech extraction versus Head pushing to deliver the impacted fetal head in advanced labor requiring emergency Cesarean section. Method: A prospective comparative study was conducted on 80 pregnant women at term with cephalic presentation in advanced labour, requiring emergency Cesarean Section. Reverse breech extraction technique (pull method) was used in 40 cases (group I) and pushing the head up through the vagina (“push” method) was tried in (group II) 40 cases. The maternal outcome was assessed by extension of the uterine Incision, bladder injury, intra and postoperative blood transfusion, Postpartum hemorrhage, wound infection and duration of hospital stay. Fetal outcome was Apgar score and admission to neonatal intensive care unit. Results: Extension of the uterine incision was significantly lower in women undergoing reverse breech extraction compared to cephalic delivery (20% versus 50%;p = 0.001). The mean operative time (pull group) was lower than that in the (push group) 59.7 ± 4.2, versus 75.2 ± 6.1 p = 0.001 and blood loss was significantly lower in the (pull group) than that in the (push group) 878 ± 67 ml, versus 1321 ± 57 ml, p = 0.001. No significant difference between groups regarding maternal and neonatal outcome. Conclusion: Reverse breech extraction (pull) is safer than pushing head up through vagina (push) for delivery of a deeply impacted fetal head in advanced labour sensitizing emergency Cesarean Section and is associated with the least maternal complications.
文摘The 25 years＇ production and application have proved that vermicular graphite iron cylinder heads with vermicularity ≥50% satisfy the machinability and performance demand of diesel engine. The method, in which using cupola-induction furnace duplex melting and pour-over process with rare earth-ferrosilicon or rare earthsilicon compound as vermJcularizing alloy plus rare earth-magnesium-ferrosilicon as stirring alloy, is an optimal vermicularizing process for obtaining satisfied vermicularity. Using top kiss risers, enlarging kissing areas and expanding covering width and making ingates to freeze earlier are the effective measures to eliminate shrinkage, blowhole and oxide inclusions in the vermicular graphite iron cylinder heads.
基金This Study is one of the preeminent Researches in Chinese Medicine and Pharmacology supported by Jiangxi Health Care Administration. Code :2006A43~~
文摘Objective To probe methods and therapeutic effects of Head Acupuncture on ischemic stroke. Methods One hundred and twelve cases were randomly divided into observation group (head acupuncture group) and control group (body acupuncture group). After treatment of 28 days, changes of linguistic function and paralysis level of limbs before and after treatment were investigated. Results The total effective rate was 96.6% in the observation group and 90.7%, in the control group, with a significant difference between the two groups (P<0.05). Conclusion The electroacupuncture head point-through-point by penetrating two point therapy is one of effective methods for ischemic stroke.
文摘In this paper,using the reductive perturbation method combined with the PLK method and two-parameter expansions,we treat the problem of head-on collision between two solitary waves described by the generalized Korteweg-de Vries equation (the gKdV equation) and obtain its second-order approximate solution.The results show that after the collision,the gKdV solitary waves preserve their profiles and during the collision,the maximum amplitute is the linear superposition of two maximum amplitudes of the impinging solitary waves.
文摘In this study, finite difference method is used to solve the equations that govern groundwater flow to obtain flow rates, flow direction and hydraulic heads through an aquifer. The aim therefore is to discuss the principles of Finite Difference Method and its applications in groundwater modelling. To achieve this, a rectangular grid is overlain an aquifer in order to obtain an exact solution. Initial and boundary conditions are then determined. By discretizing the system into grids and cells that are small compared to the entire aquifer, exact solutions are obtained. A flow chart of the computational algorithm for particle tracking is also developed. Results show that under a steady-state flow with no recharge, pathlines coincide with streamlines. It is also found that the accuracy of the numerical solution by Finite Difference Method is largely dependent on initial particle distribution and number of particles assigned to a cell. It is therefore concluded that Finite Difference Method can be used to predict the future direction of flow and particle location within a simulation domain.
文摘The sarcoma structure of goldfish was first analyzed by frozen section technique. The present study revealed the alkaline and acid phosphatase distribution in the head sarcoma of goldfish. And the histochemical staining in situ by calcium-cobalt method and lead nitrate method displayed a large amount of alkaline and acid phosphatases in the head sarcoma, with higher enzyme activity. The alkaline and acid phosphatases belong to hydrolases, which are widely present in various tissues. The results showed that the activity of external sarcoma is similar to the middle one, while there was more alkaline phosphatase near to the tissue sarcoma under the goldfish scales. And they have the strong activity. The study will lay the theoretical basis on enhancing the ornamental value of goldfish.
文摘In this paper, we present the Projection Based Interpolation (PBI) technique for construction of continuous approximation of MRI scan data of the human head. We utilize the result of the PBI algorithm to perform three-dimensional (3D) Finite Element Method (FEM) simulations of the heating of the human head induced by cell phone. In particular, we utilize the Pennes equation to describe the bioheat transfer with the right hand side representing the heat generated by cell phone. We utilize our own non-stationary time dependent multi-thread parallel direct solver for the solution of this computational problem. From our numerical results it follows that 15 minutes (1000 seconds) exposure to the cell phone radiation implies up to 2 degrees Celsius increase of the temperature of the brain in the range close to the cell phone.
基金supported by the National Natural Science Foundation of China(No.52105161).
文摘Thin-walled torispherical heads under internal pressure can fail by plastic buckling because of compressive circumferential stresses in the head knuckle.However,existing formulas still have limitations,such as complicated expressions and low accuracy,in determining buckling pressure.In this paper,we propose a new formula for calculating the buckling pressure of torispherical heads based on elastic-plastic analysis and experimental results.First,a finite element(FE)method based on the arc-length method is established to calculate the plastic buckling pressure of torispherical heads,considering the effects of material strain hardening and geometrical nonlinearity.The buckling pressure results calculated by the FE method in this paper have good consistency with those of BOSOR5,which is a program for calculating the elastic-plastic bifurcation buckling pressure based on the finite difference energy method.Second,the effects of geometric parameters,material parameters,and restraint form of head edge on buckling pressure are investigated.Third,a new formula for calculating plastic buckling pressure is developed by fitting the curve of FE results and introducing a reduction factor determined from experimental data.Finally,based on the experimental results,we compare the predictions of the new formula with those of existing formulas.It is shown that the new formula has a higher accuracy than the existing ones.
