The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the...The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the length of 500 mm is established, with a semicircular cross section in a diameter of 1.2 mm.Numerical simulation is employed to investigate the flow and heat transfer performance of supercritical methane in the channel. The pseudo-boiling theory is adopted and the liquid-like, two-phase-like, and vapor-like regimes are divided for supercritical methane to analyze the heat transfer and flow features.The results are presented in micro segment to show the local convective heat transfer coefficient and pressure drop. It shows that the convective heat transfer coefficient in segments along the channel has a significant peak feature near the pseudo-critical point and a heat transfer deterioration when the average fluid temperature in the segment is higher than the pseudo-critical point. The reason is explained with the generation of vapor-like film near the channel wall that the peak feature related to a nucleateboiling-like state and heat transfer deterioration related to a film-boiling-like state. The effects of parameters, including mass flow rate, pressure, and wall heat flux on flow and heat transfer were analyzed.In calculating of the averaged heat transfer coefficient of the whole channel, the traditional method shows significant deviation and the micro segment weighted average method is adopted. The pressure drop can mainly be affected by the mass flux and pressure and little affected by the wall heat flux. The peak of the convective heat transfer coefficient can only form at high mass flux, low wall heat flux, and near critical pressure, in which condition the nucleate-boiling-like state is easier to appear. Moreover,heat transfer deterioration will always appear, since the supercritical flow will finally develop into a filmboiling-like state. So heat transfer deterioration should be taken seriously in the design and safe operation of vaporizer PCHE. The study of this work clarified the local heat transfer and flow feature of supercritical methane in microchannel and contributed to the deep understanding of supercritical methane flow of the vaporization process in PCHE.展开更多
Accurate preoperative diagnosis is highly important for the treatment of perivascular epithelioid cell tumors(PEComas)because PEComas are mainly benign tumors and may not require surgical intervention.By analyzing the...Accurate preoperative diagnosis is highly important for the treatment of perivascular epithelioid cell tumors(PEComas)because PEComas are mainly benign tumors and may not require surgical intervention.By analyzing the causes,properties and clinical manifestations of PEComas,we summarize the challenges and solutions in the diagnosis of PEComas.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)is the third leading cause of cancer death worldwide,with a 5-year relative survival rate of approximately 18%.The similarity between incidence and mortality(830000 deaths per y...BACKGROUND Hepatocellular carcinoma(HCC)is the third leading cause of cancer death worldwide,with a 5-year relative survival rate of approximately 18%.The similarity between incidence and mortality(830000 deaths per year)underscores the bleak prognosis associated with the disease.HCC is the fourth most common malignancy and the second leading cause of cancer death in China.Most patients with HCC have a history of chronic liver disease such as chronic hepatitis B virus(HBV)or hepatitis C virus(HCV)infection,alcoholism or alcoholic steatohepatitis,nonalcoholic fatty liver disease,or nonalcoholic steatohepatitis.Early diagnosis and effective treatment are the keys to improving the prognosis of patients with HCC.Although the total number of human immunodeficiency virus(HIV)-infected patients is declining globally the incidence of HCC is increasing in HIVinfected patients,especially those who are coinfected with HBV or HCV.As a result,people infected with HIV still face unique challenges in terms of their risk of developing HCC.AIM To investigate the survival prognosis and clinical efficacy of surgical resection in patients with HCC complicated with HIV infection.METHODS The clinical data of 56 patients with HCC complicated with HIV admitted to the Third Affiliated Hospital of Nantong University from January 2013 to December 2023 were retrospectively analyzed.Among these,27 patients underwent hepatectomy(operation group)and 29 patients received conservative treatment(nonoperation group).All patients signed informed consents in line with the provisions of medical ethics.The general data,clinicopathological features and prognoses for the patients in the two groups were analyzed and the risk factors related to the prognoses of the patients in the operation group were identified.RESULTS The median disease-free survival(DFS)and overall survival(OS)of HIV-HCC patients in the surgical group were 13 months and 17 months,respectively,and the median OS of patients in the nonsurgical group was 12 months.The OS of the surgical group was significantly longer than that of the control group(17 months vs 12 months,respectively;P<0.05).The risk factors associated with DFS and OS in the surgical group were initial HIV diagnosis,postoperative microvascular invasion(MVI),a CD4+T-cell count<200/μL,Barcelona stage C-D,and men who have sex with men(MSM;P<0.05).CONCLUSION Hepatectomy can effectively prolong the survival of patients with HIV-HCC but MVI identified during postoperative pathological examination,late tumor detection,late BCLC stage,CD4+T<200/μL and MSM are risk factors affecting the survival and prognosis of patients undergoing hepatectomy.In addition,there were significant differences between the surgical group and the nonsurgical group in terms of the initial diagnosis of HIV,Child-Pugh score,alpha-fetoprotein measurement value,and HART-efficient antiretroviral therapy after the diagnosis of HIV(P<0.05).Therefore,these factors may also affect the survival and prognosis of patients.展开更多
Mitochondrial division inhibitor 1（Mdivi-1） is a selective cell-permeable inhibitor of dynamin-related protein-1（Drp1） and mitochondrial division.To investigate the effect of Mdivi-1 on cells treated with glutamat...Mitochondrial division inhibitor 1（Mdivi-1） is a selective cell-permeable inhibitor of dynamin-related protein-1（Drp1） and mitochondrial division.To investigate the effect of Mdivi-1 on cells treated with glutamate,cerebral cortex neurons isolated from neonatal rats were treated with 10 m M glutamate for 24 hours.Normal cultured cells and dimethyl sulfoxide-cultured cells were considered as controls.Apoptotic cells were detected by flow cytometry.Changes in mitochondrial morphology were examined by electron microscopy.Drp1,Bax,and casp ase-3 expression was evaluated by western blot assays and immunocytochemistry.Mitochondrial membrane potential was detected using the JC-1 probe.Twenty-four hours after 10 m M glutamate treatment,Drp1,Bax and caspase-3 expression was upregulated,Drp1 and Bax were translocated to mitochondria,mitochondrial membrane potential was decreased and the rate of apoptosis was increased.These effects were inhibited by treatment with 50 μM Mdivi-1 for 2 hours.This finding indicates that Mdivi-1 is a candidate neuroprotective drug that can potentially mitigate against neuronal injury caused by glutamate-induced excitotoxicity.展开更多
The influence of liquid viscoelasticity on the interaction between cavitation bubbles and free surfaces is of great practical significance in understanding bubble dynamics in biological systems. A series of millimeter...The influence of liquid viscoelasticity on the interaction between cavitation bubbles and free surfaces is of great practical significance in understanding bubble dynamics in biological systems. A series of millimeter cavitation bubbles were induced by laser near the free surfaces of the water and viscoelastic polyacrylamide (PAM) solutions with different concentrations. The effects of liquid viscoelasticity on the interactions of cavitation bubbles with free surfaces are analyzed from the perspectives of the evolution of free surface and bubble dynamics. The experimental results show that as the dimensionless standoff distance increases, the evolutions of free surface behaviors in all experimental fluids can be divided into six types of water mounds, i.e., breaking wrinkles, spraying water film, crown, swallowed water spike, hillock, and slight bulge. All the critical values of the dimensionless distance dividing different types decrease with increasing concentration. The evolutions of first four types of water mounds in PAM solutions differ from those in the water. Water droplets splashing in different directions are produced around the breaking wrinkles in the water. Meanwhile, the breaking wrinkles in PAM solution move with the “liquid filaments” towards the central axis. The water spike in the pattern of spraying water film in PAM solution is more stable than that in the water. As the solution concentration increases, the water skirt in the pattern of crown contracts earlier and faster, and the rate of increase in the height of the water skirt decreases. For swallowed water spike in PAM solution, the upper part of the newly formed water spike is not significantly thicker than the middle part, and thus the water waist structure does not form. Liquid viscoelasticity inhibits the bubble growth and collapse, and the bubble migration as well, especially in the second period. Shorter and thicker cavities are formed in PAM solutions with higher concentration, while slender and stable cavities formed in the water at the same dimensionless distance. The velocity and displacement of the tip of bullet jet both decrease as the solution concentration increases.展开更多
The vortex structure plays a significant role in the investigation of the turbulent drag reduction effect of the viscoelastic turbulent flow.This paper aims to find out an optimal vortex identification method for the ...The vortex structure plays a significant role in the investigation of the turbulent drag reduction effect of the viscoelastic turbulent flow.This paper aims to find out an optimal vortex identification method for the viscoelastic turbulent flows,and then studies the turbulent drag reduction mechanism by analyzing the characteristics of the identified vortex structures in the turbulent flows of the viscoelastic fluids.The Q,λ2,Liutex,Omega(Ω)and Omega-Liutex(ΩR)methods are adopted for the identification of vortex structures in the forced homogeneous isotropic turbulence(FHIT)with/without the polymer additive,respectively.The comparison among these five methods shows that the threshold values for the Q,λ2 and Liutex methods should be specially adjusted so as to suitably describe the strong and weak vortex structures in the FHIT of both the Newtonian and viscoelastic fluids,while a fixed threshold value of 0.52 for theΩandΩR methods is effective for both the Newtonian and viscoelastic fluids.The comparison between the identified vortex structures in the FHIT with and without the polymer additive indicates that theΩandΩR methods are more appropriate for the vortex identification because their dimensionless values with a fixed range from 0 to 1 can avoid the effect of the different ranges of the Q,λ2 and∣R∣(for the Liutex method)for the Newtonian and viscoelastic fluids.This also illustrates that theΩandΩR methods can be extended to identify the vortex structures in the turbulent flow of the viscoelastic fluid.Finally,the characteristics of the vortex structures in the FHIT of the viscoelastic fluid are analyzed by utilizing theΩandΩR methods.The results show that both the strong and weak vortex structures are inhibited by increasing the concentration of the polymer solution and by decreasing the Weissenberg number,especially for the weak vortex structures.展开更多
In view of the supercavitation effect, a novel device named the rotational supercavitating evaporator (RSCE) has been designed for the desalination. In order to improve the blade shape of the rotational cavitator in t...In view of the supercavitation effect, a novel device named the rotational supercavitating evaporator (RSCE) has been designed for the desalination. In order to improve the blade shape of the rotational cavitator in the RSCE for the performance optimization, the blade shapes of different sizes are designed by utilizing the improved calculation method for the blade shape and the validated empirical formulae based on previous two-dimensional numerical simulations, from which the optimized blade shape with the wedge angle of 45° and the design speed of 5 000 r/min is selected. The estimation method for the desalination performance parameters is developed to validate the feasibility of the utilization of the results obtained by the two-dimensional numerical simulations in the design of the three-dimensional blade shape. Three-dimensional numerical simulations are then conducted for the supercavitating flows around the rotational cavitator with the optimized blade shape at different rotational speeds to obtain the morphological characteristics of the rotational natural supercavitation. The results show that the profile of the supercavity tail is concaved toward the inside of the supercavity due to the re-entrant jet. The empirical formulae for estimating the supercavity size with consideration of the rotation are obtained by fitting the data, with the exponents different from those obtained by the previous two-dimensional numerical simulations. The influences of the rotation on the morphological characteristics are analyzed from the perspectives of the tip and hub vortices and the interaction between the supercavity tail and the blade. Further numerical simulation of the supercavitating flow around the rotational cavitator made up by the blades with exit edge of uniform thickness illustrate that the morphological characteristics are also affected by the blade shape.展开更多
基金provided by Science and Technology Development Project of Jilin Province(No.20230101338JC)。
文摘The printed circuit heat exchanger(PCHE) is receiving wide attention as a new kind of compact heat exchanger and is considered as a promising vaporizer in the LNG process. In this paper, a PCHE straight channel in the length of 500 mm is established, with a semicircular cross section in a diameter of 1.2 mm.Numerical simulation is employed to investigate the flow and heat transfer performance of supercritical methane in the channel. The pseudo-boiling theory is adopted and the liquid-like, two-phase-like, and vapor-like regimes are divided for supercritical methane to analyze the heat transfer and flow features.The results are presented in micro segment to show the local convective heat transfer coefficient and pressure drop. It shows that the convective heat transfer coefficient in segments along the channel has a significant peak feature near the pseudo-critical point and a heat transfer deterioration when the average fluid temperature in the segment is higher than the pseudo-critical point. The reason is explained with the generation of vapor-like film near the channel wall that the peak feature related to a nucleateboiling-like state and heat transfer deterioration related to a film-boiling-like state. The effects of parameters, including mass flow rate, pressure, and wall heat flux on flow and heat transfer were analyzed.In calculating of the averaged heat transfer coefficient of the whole channel, the traditional method shows significant deviation and the micro segment weighted average method is adopted. The pressure drop can mainly be affected by the mass flux and pressure and little affected by the wall heat flux. The peak of the convective heat transfer coefficient can only form at high mass flux, low wall heat flux, and near critical pressure, in which condition the nucleate-boiling-like state is easier to appear. Moreover,heat transfer deterioration will always appear, since the supercritical flow will finally develop into a filmboiling-like state. So heat transfer deterioration should be taken seriously in the design and safe operation of vaporizer PCHE. The study of this work clarified the local heat transfer and flow feature of supercritical methane in microchannel and contributed to the deep understanding of supercritical methane flow of the vaporization process in PCHE.
基金Supported by Nantong Municipal Health Commission,No.MSZ2022036.
文摘Accurate preoperative diagnosis is highly important for the treatment of perivascular epithelioid cell tumors(PEComas)because PEComas are mainly benign tumors and may not require surgical intervention.By analyzing the causes,properties and clinical manifestations of PEComas,we summarize the challenges and solutions in the diagnosis of PEComas.
基金Nantong Municipal Health Commission,No.MSZ2022036.
文摘BACKGROUND Hepatocellular carcinoma(HCC)is the third leading cause of cancer death worldwide,with a 5-year relative survival rate of approximately 18%.The similarity between incidence and mortality(830000 deaths per year)underscores the bleak prognosis associated with the disease.HCC is the fourth most common malignancy and the second leading cause of cancer death in China.Most patients with HCC have a history of chronic liver disease such as chronic hepatitis B virus(HBV)or hepatitis C virus(HCV)infection,alcoholism or alcoholic steatohepatitis,nonalcoholic fatty liver disease,or nonalcoholic steatohepatitis.Early diagnosis and effective treatment are the keys to improving the prognosis of patients with HCC.Although the total number of human immunodeficiency virus(HIV)-infected patients is declining globally the incidence of HCC is increasing in HIVinfected patients,especially those who are coinfected with HBV or HCV.As a result,people infected with HIV still face unique challenges in terms of their risk of developing HCC.AIM To investigate the survival prognosis and clinical efficacy of surgical resection in patients with HCC complicated with HIV infection.METHODS The clinical data of 56 patients with HCC complicated with HIV admitted to the Third Affiliated Hospital of Nantong University from January 2013 to December 2023 were retrospectively analyzed.Among these,27 patients underwent hepatectomy(operation group)and 29 patients received conservative treatment(nonoperation group).All patients signed informed consents in line with the provisions of medical ethics.The general data,clinicopathological features and prognoses for the patients in the two groups were analyzed and the risk factors related to the prognoses of the patients in the operation group were identified.RESULTS The median disease-free survival(DFS)and overall survival(OS)of HIV-HCC patients in the surgical group were 13 months and 17 months,respectively,and the median OS of patients in the nonsurgical group was 12 months.The OS of the surgical group was significantly longer than that of the control group(17 months vs 12 months,respectively;P<0.05).The risk factors associated with DFS and OS in the surgical group were initial HIV diagnosis,postoperative microvascular invasion(MVI),a CD4+T-cell count<200/μL,Barcelona stage C-D,and men who have sex with men(MSM;P<0.05).CONCLUSION Hepatectomy can effectively prolong the survival of patients with HIV-HCC but MVI identified during postoperative pathological examination,late tumor detection,late BCLC stage,CD4+T<200/μL and MSM are risk factors affecting the survival and prognosis of patients undergoing hepatectomy.In addition,there were significant differences between the surgical group and the nonsurgical group in terms of the initial diagnosis of HIV,Child-Pugh score,alpha-fetoprotein measurement value,and HART-efficient antiretroviral therapy after the diagnosis of HIV(P<0.05).Therefore,these factors may also affect the survival and prognosis of patients.
基金supported by the National Natural Science Foundation of China,No.81371967 and 81401807a grant from the 5th Phase of "Project 333"of Jiangsu Province of China,No.BRA2016512a grant from the Six Talent Peaks Project of Jiangsu Province of China,No.2014-WSN-012
文摘Mitochondrial division inhibitor 1（Mdivi-1） is a selective cell-permeable inhibitor of dynamin-related protein-1（Drp1） and mitochondrial division.To investigate the effect of Mdivi-1 on cells treated with glutamate,cerebral cortex neurons isolated from neonatal rats were treated with 10 m M glutamate for 24 hours.Normal cultured cells and dimethyl sulfoxide-cultured cells were considered as controls.Apoptotic cells were detected by flow cytometry.Changes in mitochondrial morphology were examined by electron microscopy.Drp1,Bax,and casp ase-3 expression was evaluated by western blot assays and immunocytochemistry.Mitochondrial membrane potential was detected using the JC-1 probe.Twenty-four hours after 10 m M glutamate treatment,Drp1,Bax and caspase-3 expression was upregulated,Drp1 and Bax were translocated to mitochondria,mitochondrial membrane potential was decreased and the rate of apoptosis was increased.These effects were inhibited by treatment with 50 μM Mdivi-1 for 2 hours.This finding indicates that Mdivi-1 is a candidate neuroprotective drug that can potentially mitigate against neuronal injury caused by glutamate-induced excitotoxicity.
基金Project supported by the National Natural Science Foundation of China(Grant No.51806051).
文摘The influence of liquid viscoelasticity on the interaction between cavitation bubbles and free surfaces is of great practical significance in understanding bubble dynamics in biological systems. A series of millimeter cavitation bubbles were induced by laser near the free surfaces of the water and viscoelastic polyacrylamide (PAM) solutions with different concentrations. The effects of liquid viscoelasticity on the interactions of cavitation bubbles with free surfaces are analyzed from the perspectives of the evolution of free surface and bubble dynamics. The experimental results show that as the dimensionless standoff distance increases, the evolutions of free surface behaviors in all experimental fluids can be divided into six types of water mounds, i.e., breaking wrinkles, spraying water film, crown, swallowed water spike, hillock, and slight bulge. All the critical values of the dimensionless distance dividing different types decrease with increasing concentration. The evolutions of first four types of water mounds in PAM solutions differ from those in the water. Water droplets splashing in different directions are produced around the breaking wrinkles in the water. Meanwhile, the breaking wrinkles in PAM solution move with the “liquid filaments” towards the central axis. The water spike in the pattern of spraying water film in PAM solution is more stable than that in the water. As the solution concentration increases, the water skirt in the pattern of crown contracts earlier and faster, and the rate of increase in the height of the water skirt decreases. For swallowed water spike in PAM solution, the upper part of the newly formed water spike is not significantly thicker than the middle part, and thus the water waist structure does not form. Liquid viscoelasticity inhibits the bubble growth and collapse, and the bubble migration as well, especially in the second period. Shorter and thicker cavities are formed in PAM solutions with higher concentration, while slender and stable cavities formed in the water at the same dimensionless distance. The velocity and displacement of the tip of bullet jet both decrease as the solution concentration increases.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51706050,51806051).
文摘The vortex structure plays a significant role in the investigation of the turbulent drag reduction effect of the viscoelastic turbulent flow.This paper aims to find out an optimal vortex identification method for the viscoelastic turbulent flows,and then studies the turbulent drag reduction mechanism by analyzing the characteristics of the identified vortex structures in the turbulent flows of the viscoelastic fluids.The Q,λ2,Liutex,Omega(Ω)and Omega-Liutex(ΩR)methods are adopted for the identification of vortex structures in the forced homogeneous isotropic turbulence(FHIT)with/without the polymer additive,respectively.The comparison among these five methods shows that the threshold values for the Q,λ2 and Liutex methods should be specially adjusted so as to suitably describe the strong and weak vortex structures in the FHIT of both the Newtonian and viscoelastic fluids,while a fixed threshold value of 0.52 for theΩandΩR methods is effective for both the Newtonian and viscoelastic fluids.The comparison between the identified vortex structures in the FHIT with and without the polymer additive indicates that theΩandΩR methods are more appropriate for the vortex identification because their dimensionless values with a fixed range from 0 to 1 can avoid the effect of the different ranges of the Q,λ2 and∣R∣(for the Liutex method)for the Newtonian and viscoelastic fluids.This also illustrates that theΩandΩR methods can be extended to identify the vortex structures in the turbulent flow of the viscoelastic fluid.Finally,the characteristics of the vortex structures in the FHIT of the viscoelastic fluid are analyzed by utilizing theΩandΩR methods.The results show that both the strong and weak vortex structures are inhibited by increasing the concentration of the polymer solution and by decreasing the Weissenberg number,especially for the weak vortex structures.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51806051,51706050,51276046 and 51576051).
文摘In view of the supercavitation effect, a novel device named the rotational supercavitating evaporator (RSCE) has been designed for the desalination. In order to improve the blade shape of the rotational cavitator in the RSCE for the performance optimization, the blade shapes of different sizes are designed by utilizing the improved calculation method for the blade shape and the validated empirical formulae based on previous two-dimensional numerical simulations, from which the optimized blade shape with the wedge angle of 45° and the design speed of 5 000 r/min is selected. The estimation method for the desalination performance parameters is developed to validate the feasibility of the utilization of the results obtained by the two-dimensional numerical simulations in the design of the three-dimensional blade shape. Three-dimensional numerical simulations are then conducted for the supercavitating flows around the rotational cavitator with the optimized blade shape at different rotational speeds to obtain the morphological characteristics of the rotational natural supercavitation. The results show that the profile of the supercavity tail is concaved toward the inside of the supercavity due to the re-entrant jet. The empirical formulae for estimating the supercavity size with consideration of the rotation are obtained by fitting the data, with the exponents different from those obtained by the previous two-dimensional numerical simulations. The influences of the rotation on the morphological characteristics are analyzed from the perspectives of the tip and hub vortices and the interaction between the supercavity tail and the blade. Further numerical simulation of the supercavitating flow around the rotational cavitator made up by the blades with exit edge of uniform thickness illustrate that the morphological characteristics are also affected by the blade shape.
