Cu–Ni and Cu–Co–Ni superhydrophobic films were constructed on the surface of B10 copper–nickel alloy welded joints using a two-step process of electrodeposition and stearic acid modification.The chemical compositi...Cu–Ni and Cu–Co–Ni superhydrophobic films were constructed on the surface of B10 copper–nickel alloy welded joints using a two-step process of electrodeposition and stearic acid modification.The chemical composition of the film surface was determined using surface characterization techniques.The corrosion resistance of the films was characterized using electrochemical impedance spectroscopy,potentiodynamic polarization,and scanning Kelvin probe microscopy at multiple scales.The thermal stability,mechanical stability,and self-cleaning properties of the films were also characterized.It was determined that the Cu–Co–Ni superhydrophobic film exhibited the best performance,with a static water contact angle of 159.3°,a roll-off angle of 2.3°,a charge transfer resistance 3300 times higher than the substrate,a self-corrosion current density nearly three orders of magnitude lower,and a surface Kelvin potential increase of 420 mV.The film demonstrated good thermal stability,excellent mechanical stability,and outstanding self-cleaning properties.Combining with previous studies,it was found that Co elements in the film contribute to the formation of a uniform and dense film,Ni elements enhance the adhesion and corrosion resistance between the films,and the combination of Co and Ni elements promotes uniform surface potential and further improves the corrosion resistance and interfilm adhesion of the films.展开更多
BACKGROUND Colorectal cancer(CRC)is a malignant tumor characterized by high global incidence and mortality rates.Contemporary therapeutic modalities remain limited by suboptimal efficacy and adverse effects,thereby ne...BACKGROUND Colorectal cancer(CRC)is a malignant tumor characterized by high global incidence and mortality rates.Contemporary therapeutic modalities remain limited by suboptimal efficacy and adverse effects,thereby necessitating the pursuit of more efficacious treatment strategies.Within traditional Chinese medicine,spleen deficiency is regarded as a central pathogenic mechanism in CRC,persisting throughout the entire disease course.AIM To elucidate the mechanism by which modified Yigong San confers therapeutic efficacy against CRC,potentially exerting its effects through apoptosis regulation mediated by the enhancer of zeste homolog 2(EZH2)/methyltransferase-like 3(METTL3)/SRY-box transcription factor 4(SOX4)axis.METHODS In the clinical study,CRC tissues and corresponding adjacent normal samples that fulfilled inclusion criteria were procured.Quantitative reverse transcription polymerase chain reaction was employed to determine the transcriptional expression of EZH2 and METTL3 mRNA.For in vitro experimentation,SW-480 cells were allocated into five experimental conditions:Control,control+serum,control+negative control,control+overexpressing-EZH2,and control+overexpressing-EZH2+serum.The mRNA expression levels of EZH2,METTL3,SOX4,B-cell lymphoma 2,and Bax across groups were quantified via quantitative reverse transcription polymerase chain reaction,while protein levels were assessed using western blot analysis.The presence of EZH2 binding sites within the METTL3 promoter region was verified through chromatin immunoprecipitation polymerase chain reaction.The optimal concentration of drug-containing serum(5%,10%,15%)was determined using the Cell Counting Kit-8 assay.Cell migratory ability was evaluated via scratch assays,and apoptotic activity was quantified by flow cytometry.RESULTS The clinical findings demonstrated significantly elevated transcriptional levels of METTL3 and EZH2 mRNA in tumor tissues compared to their adjacent normal counterparts(P<0.05).In vitro,cells treated with modified Yigong San exhibited a substantial downregulation of EZH2,METTL3,SOX4,B-cell lymphoma 2,and Bax mRNA and protein levels(P<0.05),relative to the control group.Apoptotic rates were markedly increased,while migratory capacity was significantly attenuated.Furthermore,in EZH2-overexpressing cells treated with modified Yigong San,similar reductions in both mRNA and protein levels of the aforementioned targets were observed(P<0.05),concomitant with enhanced apoptosis and reduced migration.Chromatin immunoprecipitation polymerase chain reaction analysis confirmed EZH2 occupancy at specific loci within the METTL3 promoter.CONCLUSION Modified Yigong San exhibits both preventive and therapeutic potential against CRC,likely mediated through the regulation of apoptosis via the EZH2/METTL3/SOX4 signaling pathway.展开更多
Objective： A meta-analysis was performed to augment the insufficient data on the impact of mutative EGFR downstream phosphatidylinositol-3-kinase （PI3K） and mitogen-activated protein kinase （MAPK） pathways on the...Objective： A meta-analysis was performed to augment the insufficient data on the impact of mutative EGFR downstream phosphatidylinositol-3-kinase （PI3K） and mitogen-activated protein kinase （MAPK） pathways on the clinical efficiency of epidermal growth factor receptor tyrosine kinase inhibitor （EGFR-TKI） treatment of non-small cell lung cancer （NSCLC） patients. Methods： Network databases were explored in April, 2015. Papers that investigated the clinical outcomes of NSCLC patients treated with EGFR-TKIs according to the status of K-ras and/or PIK3CA gene mutation were included. A quantitative meta-analysis was conducted using standard statistical methods. Odds ratios （ORs） for objective response rate （ORR） and hazard ratios （HRs） for progression-free survival （PFS） and overall survival （OS） were calculated. Results： Mutation in K-ras significantly predicted poor ORR [OR =0.22; 95% confidence interval （CI）, 0.13-0.35], shorter PFS （HR =1.56; 95% CI, 1.27-1.92）, and shorter OS （HR =1.59; 95% CI, 1.33-1.91） in NSCLC patients treated with EGFR-TKIs. Mutant PIK3CA significantly predicted shorter OS （HR =1.83; 95% CI, 1.05-3.20）, showed poor ORR （OK =0.70; 95% CI, 0.22-2.18）, and shorter PFS （HR = 1.79; 95% CI, 0.91-3.53） in NSCLC patients treated with EGFR-TKIs. Conclusion： K-ras mutation adversely affected the clinical response and survival of NSCLC patients treated with EGFR- TKIs. PIK3CA mutation showed similar trends. In addition to EGFR, adding K-ras and PIK3CA as routine gene biomarkers in clinical genetic analysis is valuable to optimize the effectiveness of EGFR-TKI regimens and identify optimal patients who will benefit from EGFR-TKI treatment.展开更多
BACKGROUND At present,colorectal cancer is routinely treated with adjuvant radiotherapy and chemotherapy postoperatively.The adverse effects(AEs)of chemotherapy usually interrupt the treatment of chemotherapy.Traditio...BACKGROUND At present,colorectal cancer is routinely treated with adjuvant radiotherapy and chemotherapy postoperatively.The adverse effects(AEs)of chemotherapy usually interrupt the treatment of chemotherapy.Traditional Chinese medicine(TCM)has demonstrated great potential in improving patients'clinical symptoms,regulating the immune function,improving the life quality,and reducing the AEs of chemotherapy.AIM To observe the clinical efficacy of Yiqi Jianpi anti-cancer prescription combined with chemotherapy in patients with colorectal cancer after operation.METHODS Data from patients diagnosed with colorectal cancer between January 2019 and February 2021 were collected from Liaoning Cancer Hospital and Institute and the Second Affiliated Hospital of Liaoning University of Traditional Chinese Medicine.Patients receiving the chemotherapy regimen of capecitabine plus oxaliplatin(CAPOX)after radical resection of colorectal cancer were prospectively collected and randomly divided into an experimental group and a control group.The experimental group was given Yiqi Jianpi anti-cancer prescription combined with the CAPOX regimen,while the control group was given the CAPOX regimen alone.After six cycles of chemotherapy,the scores of TCM symptoms,Karnofsky performance scale(KPS)score,levels of T-cell subsets,and AEs after chemo therapy of the two groups were compared.RESULTS A total of 70 patients were randomly divided into either an experimental group(n=35,no dropout)or a control group(n=33,with 2 dropouts).Compared with the control group,the experimental group improved significantly(P<0.05)in scores of TCM symptoms,KPS score,levels of T-cell subsets,and AEs of chemotherapy.CONCLUSION Yiqi Jianpi anti-cancer prescription can effectively improve spleen deficiency,regulate the immune function,and alleviate the AEs of chemotherapy,so as to improve the life quality of patients with good therapeutic effects and application prospect in clinical practice.展开更多
The corrosion behavior of B10 copper-nickel alloy welded joints in seawater pipeline system was analyzed under local turbulence induced by weld residual height.The corrosion behavior was evaluated by array electrode t...The corrosion behavior of B10 copper-nickel alloy welded joints in seawater pipeline system was analyzed under local turbulence induced by weld residual height.The corrosion behavior was evaluated by array electrode technology,mor-phology and elemental characterization,and COMSOL Multiphysics simulation.The results provide a theoretical basis for the corrosion and leakage of B10 alloy in seawater pipeline under the action of turbulence.The results show that residual height-induced turbulence exhibits a significant effect on the corrosion behavior in different areas of welded joints in B10 alloy.Turbulence can damage some surfaces,causing polarity deflection followed by acceleration of corrosion,or it is easier to form a protective film to slow down corrosion.COMSOL Multiphysics results show that the shear rate and turbulent kinetic energy increase linearly with the increase in residual height and velocity.The corrosion behavior of alloy surface is influenced by controlling the mass transfer rate and surface state.展开更多
BACKGROUND Bronchogenic cysts are cystic masses caused by congenital abnormal development of the respiratory system,and usually occur in the pulmonary parenchyma or mediastinum.CASE SUMMARY A rare case of a bronchogen...BACKGROUND Bronchogenic cysts are cystic masses caused by congenital abnormal development of the respiratory system,and usually occur in the pulmonary parenchyma or mediastinum.CASE SUMMARY A rare case of a bronchogenic cyst discovered in the abdominal cavity of a 35-year-old man is reported.Physical examination found a space-occupying lesion in the patient’s abdomen for 4 d.Laparoscopic exploration found the cyst tightly adhered to the stomach and its peripheral blood vessels;therefore,intraoperative laparotomy was performed.The cystic mass was resected en bloc with an Endo-GIA stapler.The final postoperative pathological diagnosis confirmed an abdominal bronchogenic cyst.CONCLUSION This is a rare case of a bronchogenic cyst that was discovered within the abdominal cavity of a male patient.The cyst is easily confused with or misdiagnosed as other lesions.Therefore,it is necessary to distinguish abdominal bronchogenic cyst from gastrointestinal stromal tumor,Meckel’s diverticulum,enteric duplication cyst,or lymphangioma.Although computer tomography and magnetic resonance imaging were the primary diagnostic approaches,endoscopic ultrasound-guided fine-needle aspiration could assist with clarification of the cytological or histopathological diagnosis before surgery.展开更多
The magnetic field is one of the most important parameters in solar physics,and a polarimeter is the key device to measure the solar magnetic field.Liquid crystals based Stokes polarimeter is a novel technology,and wi...The magnetic field is one of the most important parameters in solar physics,and a polarimeter is the key device to measure the solar magnetic field.Liquid crystals based Stokes polarimeter is a novel technology,and will be applied for magnetic field measurement in the first space-based solar observatory satellite developed by China,Advanced Space-based Solar Observatory.However,the liquid crystals based Stokes polarimeter in space is not a mature technology.Therefore,it is of great scientific significance to study the control method and characteristics of the device.The retardation produced by a liquid crystal variable retarder is sensitive to the temperature,and the retardation changes 0.09°per 0.10℃.The error in polarization measurement caused by this change is 0.016,which affects the accuracy of magnetic field measurement.In order to ensure the stability of its performance,this paper proposes a high-precision temperature control system for liquid crystals based Stokes polarimeter in space.In order to optimize the structure design and temperature control system,the temperature field of liquid crystals based Stokes polarimeter is analyzed by the finite element method,and the influence of light on the temperature field of the liquid crystal variable retarder is analyzed theoretically.By analyzing the principle of highprecision temperature measurement in space,a high-precision temperature measurement circuit based on integrated operational amplifier,programmable amplifier and 12 bit A/D is designed,and a high-precision space temperature control system is developed by applying the integral separation PI temperature control algorithm and PWM driving heating films.The experimental results show that the effect of temperature control is accurate and stable,whenever the liquid crystals based Stokes polarimeter is either in the air or vacuum.The temperature stability is within±0.0150℃,which demonstrates greatly improved stability for the liquid crystals based Stokes polarimeter.展开更多
A two-dimensional axisymmetric model, employing a dynamic mesh and user-defined functions, is used to numerically simulate the transient multiphase flow field produced by an underwater gun. Furthermore, a visualized s...A two-dimensional axisymmetric model, employing a dynamic mesh and user-defined functions, is used to numerically simulate the transient multiphase flow field produced by an underwater gun. Furthermore, a visualized shooting experiment platform with a high-speed camera is built to observe the evolution process of such a multiphase flow field. The simulated phase distribution diagram is agreed well with the shadow photo of the experiment, indicating that the numerical model is reasonable. Further examinations of the multiphase flow fields by using the submerged and sealed launch methods show that use of the sealed launch can significantly improve the interior ballistic performance of an underwater gun. In the cases by using these two types of underwater launch methods, the displacement of the projectile within the range of the muzzle flow field meets the exponential law over time. Moreover, a not fully developed bottle-shaped shock wave is formed when t = 0.4 ms, but this bottle-shaped shock wave expands more rapidly for the sealed launch. In addition, the amplitude of pressure oscillation for the sealed launch is larger than that of the submerged launch, but the pressure oscillation of the sealed launch lasts shorter.展开更多
Corrosion failure accidents owing to flow erosion and pipeline corrosion frequently occur during transportation.The welding reinforcement height(WRH)can induce locally micro-turbulent flow field,which aggravates local...Corrosion failure accidents owing to flow erosion and pipeline corrosion frequently occur during transportation.The welding reinforcement height(WRH)can induce locally micro-turbulent flow field,which aggravates local corrosion of welded joints.A high wall shear stress(WsS)experimental setup was established to conduct the online electrochemical corrosion test.The influence of WRH sizes on local corrosion of welded joints was studied at different flow rates.The electrochemical signals of the local corrosion of X80 welded joints at different flow rates were monitored in real time using electrochemical impedance spectroscopy and wire beam microelectrode.In addition,the corrosion products composition and properties were analyzed.The results show that the micro-turbulent flow fields induced by the WRHs can enhance ion mass transfer near the welded joints.The corrosion products on the WRH surface also present different microscopic morphologies at different flow rates.In strong flow fields,the locally enhanced wsS can peel off the dense corrosion product partially,leading to the electrochemical distribution of large cathode and small anode,which accelerates the occurrence and development processes of the local corrosion of welded joints.The scientific guidelines for the corrosion protection of long-distance oil and gas pipelines can be potentially provided.展开更多
基金fnancial support by the National Natural Science Foundation of China(Grant No.42176209)the Natural Science Foundation of Shandong Province(Grant No.ZR2021MD064).
文摘Cu–Ni and Cu–Co–Ni superhydrophobic films were constructed on the surface of B10 copper–nickel alloy welded joints using a two-step process of electrodeposition and stearic acid modification.The chemical composition of the film surface was determined using surface characterization techniques.The corrosion resistance of the films was characterized using electrochemical impedance spectroscopy,potentiodynamic polarization,and scanning Kelvin probe microscopy at multiple scales.The thermal stability,mechanical stability,and self-cleaning properties of the films were also characterized.It was determined that the Cu–Co–Ni superhydrophobic film exhibited the best performance,with a static water contact angle of 159.3°,a roll-off angle of 2.3°,a charge transfer resistance 3300 times higher than the substrate,a self-corrosion current density nearly three orders of magnitude lower,and a surface Kelvin potential increase of 420 mV.The film demonstrated good thermal stability,excellent mechanical stability,and outstanding self-cleaning properties.Combining with previous studies,it was found that Co elements in the film contribute to the formation of a uniform and dense film,Ni elements enhance the adhesion and corrosion resistance between the films,and the combination of Co and Ni elements promotes uniform surface potential and further improves the corrosion resistance and interfilm adhesion of the films.
基金Supported by Liaoning Provincial Science and Technology Department Project,No.2023JH2/101700149Open Fund Project of Liaoning University of Traditional Chinese Medicine,No.zyzx2205.
文摘BACKGROUND Colorectal cancer(CRC)is a malignant tumor characterized by high global incidence and mortality rates.Contemporary therapeutic modalities remain limited by suboptimal efficacy and adverse effects,thereby necessitating the pursuit of more efficacious treatment strategies.Within traditional Chinese medicine,spleen deficiency is regarded as a central pathogenic mechanism in CRC,persisting throughout the entire disease course.AIM To elucidate the mechanism by which modified Yigong San confers therapeutic efficacy against CRC,potentially exerting its effects through apoptosis regulation mediated by the enhancer of zeste homolog 2(EZH2)/methyltransferase-like 3(METTL3)/SRY-box transcription factor 4(SOX4)axis.METHODS In the clinical study,CRC tissues and corresponding adjacent normal samples that fulfilled inclusion criteria were procured.Quantitative reverse transcription polymerase chain reaction was employed to determine the transcriptional expression of EZH2 and METTL3 mRNA.For in vitro experimentation,SW-480 cells were allocated into five experimental conditions:Control,control+serum,control+negative control,control+overexpressing-EZH2,and control+overexpressing-EZH2+serum.The mRNA expression levels of EZH2,METTL3,SOX4,B-cell lymphoma 2,and Bax across groups were quantified via quantitative reverse transcription polymerase chain reaction,while protein levels were assessed using western blot analysis.The presence of EZH2 binding sites within the METTL3 promoter region was verified through chromatin immunoprecipitation polymerase chain reaction.The optimal concentration of drug-containing serum(5%,10%,15%)was determined using the Cell Counting Kit-8 assay.Cell migratory ability was evaluated via scratch assays,and apoptotic activity was quantified by flow cytometry.RESULTS The clinical findings demonstrated significantly elevated transcriptional levels of METTL3 and EZH2 mRNA in tumor tissues compared to their adjacent normal counterparts(P<0.05).In vitro,cells treated with modified Yigong San exhibited a substantial downregulation of EZH2,METTL3,SOX4,B-cell lymphoma 2,and Bax mRNA and protein levels(P<0.05),relative to the control group.Apoptotic rates were markedly increased,while migratory capacity was significantly attenuated.Furthermore,in EZH2-overexpressing cells treated with modified Yigong San,similar reductions in both mRNA and protein levels of the aforementioned targets were observed(P<0.05),concomitant with enhanced apoptosis and reduced migration.Chromatin immunoprecipitation polymerase chain reaction analysis confirmed EZH2 occupancy at specific loci within the METTL3 promoter.CONCLUSION Modified Yigong San exhibits both preventive and therapeutic potential against CRC,likely mediated through the regulation of apoptosis via the EZH2/METTL3/SOX4 signaling pathway.
基金supported by Key Projects in the National Science & Technology Pillar Program (Grant No. 2013ZX09303001, 2015BAI12B12, and 2015BAI12B15)National Natural Science Foundation of China (Grant No. 81472473 and 81272360)Tianjin Municipal Commission of Science & Technology Key Research Program (Grant No.13ZCZCSY20300)
文摘Objective： A meta-analysis was performed to augment the insufficient data on the impact of mutative EGFR downstream phosphatidylinositol-3-kinase （PI3K） and mitogen-activated protein kinase （MAPK） pathways on the clinical efficiency of epidermal growth factor receptor tyrosine kinase inhibitor （EGFR-TKI） treatment of non-small cell lung cancer （NSCLC） patients. Methods： Network databases were explored in April, 2015. Papers that investigated the clinical outcomes of NSCLC patients treated with EGFR-TKIs according to the status of K-ras and/or PIK3CA gene mutation were included. A quantitative meta-analysis was conducted using standard statistical methods. Odds ratios （ORs） for objective response rate （ORR） and hazard ratios （HRs） for progression-free survival （PFS） and overall survival （OS） were calculated. Results： Mutation in K-ras significantly predicted poor ORR [OR =0.22; 95% confidence interval （CI）, 0.13-0.35], shorter PFS （HR =1.56; 95% CI, 1.27-1.92）, and shorter OS （HR =1.59; 95% CI, 1.33-1.91） in NSCLC patients treated with EGFR-TKIs. Mutant PIK3CA significantly predicted shorter OS （HR =1.83; 95% CI, 1.05-3.20）, showed poor ORR （OK =0.70; 95% CI, 0.22-2.18）, and shorter PFS （HR = 1.79; 95% CI, 0.91-3.53） in NSCLC patients treated with EGFR-TKIs. Conclusion： K-ras mutation adversely affected the clinical response and survival of NSCLC patients treated with EGFR- TKIs. PIK3CA mutation showed similar trends. In addition to EGFR, adding K-ras and PIK3CA as routine gene biomarkers in clinical genetic analysis is valuable to optimize the effectiveness of EGFR-TKI regimens and identify optimal patients who will benefit from EGFR-TKI treatment.
文摘BACKGROUND At present,colorectal cancer is routinely treated with adjuvant radiotherapy and chemotherapy postoperatively.The adverse effects(AEs)of chemotherapy usually interrupt the treatment of chemotherapy.Traditional Chinese medicine(TCM)has demonstrated great potential in improving patients'clinical symptoms,regulating the immune function,improving the life quality,and reducing the AEs of chemotherapy.AIM To observe the clinical efficacy of Yiqi Jianpi anti-cancer prescription combined with chemotherapy in patients with colorectal cancer after operation.METHODS Data from patients diagnosed with colorectal cancer between January 2019 and February 2021 were collected from Liaoning Cancer Hospital and Institute and the Second Affiliated Hospital of Liaoning University of Traditional Chinese Medicine.Patients receiving the chemotherapy regimen of capecitabine plus oxaliplatin(CAPOX)after radical resection of colorectal cancer were prospectively collected and randomly divided into an experimental group and a control group.The experimental group was given Yiqi Jianpi anti-cancer prescription combined with the CAPOX regimen,while the control group was given the CAPOX regimen alone.After six cycles of chemotherapy,the scores of TCM symptoms,Karnofsky performance scale(KPS)score,levels of T-cell subsets,and AEs after chemo therapy of the two groups were compared.RESULTS A total of 70 patients were randomly divided into either an experimental group(n=35,no dropout)or a control group(n=33,with 2 dropouts).Compared with the control group,the experimental group improved significantly(P<0.05)in scores of TCM symptoms,KPS score,levels of T-cell subsets,and AEs of chemotherapy.CONCLUSION Yiqi Jianpi anti-cancer prescription can effectively improve spleen deficiency,regulate the immune function,and alleviate the AEs of chemotherapy,so as to improve the life quality of patients with good therapeutic effects and application prospect in clinical practice.
基金support from the National Natural Science Foundation of China(Grant No.42176209)the Natural Science Foundation of Shandong Province(Grant No.ZR2021MD064)the Fundamental Research Funds for the Central Universities(Grant No.19CX05001A).
文摘The corrosion behavior of B10 copper-nickel alloy welded joints in seawater pipeline system was analyzed under local turbulence induced by weld residual height.The corrosion behavior was evaluated by array electrode technology,mor-phology and elemental characterization,and COMSOL Multiphysics simulation.The results provide a theoretical basis for the corrosion and leakage of B10 alloy in seawater pipeline under the action of turbulence.The results show that residual height-induced turbulence exhibits a significant effect on the corrosion behavior in different areas of welded joints in B10 alloy.Turbulence can damage some surfaces,causing polarity deflection followed by acceleration of corrosion,or it is easier to form a protective film to slow down corrosion.COMSOL Multiphysics results show that the shear rate and turbulent kinetic energy increase linearly with the increase in residual height and velocity.The corrosion behavior of alloy surface is influenced by controlling the mass transfer rate and surface state.
文摘BACKGROUND Bronchogenic cysts are cystic masses caused by congenital abnormal development of the respiratory system,and usually occur in the pulmonary parenchyma or mediastinum.CASE SUMMARY A rare case of a bronchogenic cyst discovered in the abdominal cavity of a 35-year-old man is reported.Physical examination found a space-occupying lesion in the patient’s abdomen for 4 d.Laparoscopic exploration found the cyst tightly adhered to the stomach and its peripheral blood vessels;therefore,intraoperative laparotomy was performed.The cystic mass was resected en bloc with an Endo-GIA stapler.The final postoperative pathological diagnosis confirmed an abdominal bronchogenic cyst.CONCLUSION This is a rare case of a bronchogenic cyst that was discovered within the abdominal cavity of a male patient.The cyst is easily confused with or misdiagnosed as other lesions.Therefore,it is necessary to distinguish abdominal bronchogenic cyst from gastrointestinal stromal tumor,Meckel’s diverticulum,enteric duplication cyst,or lymphangioma.Although computer tomography and magnetic resonance imaging were the primary diagnostic approaches,endoscopic ultrasound-guided fine-needle aspiration could assist with clarification of the cytological or histopathological diagnosis before surgery.
基金the National Natural Science Foundation of China(Grant Nos.11427803,11427901 and 11773040)the Strategic Pioneer Program on Space Science,Chinese Academy of Sciences(CAS)(XDA04061002 and XDA15010800)the Public Technology Service Center,National Astronomical Observatories of CAS(829011V01)。
文摘The magnetic field is one of the most important parameters in solar physics,and a polarimeter is the key device to measure the solar magnetic field.Liquid crystals based Stokes polarimeter is a novel technology,and will be applied for magnetic field measurement in the first space-based solar observatory satellite developed by China,Advanced Space-based Solar Observatory.However,the liquid crystals based Stokes polarimeter in space is not a mature technology.Therefore,it is of great scientific significance to study the control method and characteristics of the device.The retardation produced by a liquid crystal variable retarder is sensitive to the temperature,and the retardation changes 0.09°per 0.10℃.The error in polarization measurement caused by this change is 0.016,which affects the accuracy of magnetic field measurement.In order to ensure the stability of its performance,this paper proposes a high-precision temperature control system for liquid crystals based Stokes polarimeter in space.In order to optimize the structure design and temperature control system,the temperature field of liquid crystals based Stokes polarimeter is analyzed by the finite element method,and the influence of light on the temperature field of the liquid crystal variable retarder is analyzed theoretically.By analyzing the principle of highprecision temperature measurement in space,a high-precision temperature measurement circuit based on integrated operational amplifier,programmable amplifier and 12 bit A/D is designed,and a high-precision space temperature control system is developed by applying the integral separation PI temperature control algorithm and PWM driving heating films.The experimental results show that the effect of temperature control is accurate and stable,whenever the liquid crystals based Stokes polarimeter is either in the air or vacuum.The temperature stability is within±0.0150℃,which demonstrates greatly improved stability for the liquid crystals based Stokes polarimeter.
基金This work was supported by the National Natural Science Foundation of China(No.11372139)the China Postdoctoral Science Foundation(2020M681596).
文摘A two-dimensional axisymmetric model, employing a dynamic mesh and user-defined functions, is used to numerically simulate the transient multiphase flow field produced by an underwater gun. Furthermore, a visualized shooting experiment platform with a high-speed camera is built to observe the evolution process of such a multiphase flow field. The simulated phase distribution diagram is agreed well with the shadow photo of the experiment, indicating that the numerical model is reasonable. Further examinations of the multiphase flow fields by using the submerged and sealed launch methods show that use of the sealed launch can significantly improve the interior ballistic performance of an underwater gun. In the cases by using these two types of underwater launch methods, the displacement of the projectile within the range of the muzzle flow field meets the exponential law over time. Moreover, a not fully developed bottle-shaped shock wave is formed when t = 0.4 ms, but this bottle-shaped shock wave expands more rapidly for the sealed launch. In addition, the amplitude of pressure oscillation for the sealed launch is larger than that of the submerged launch, but the pressure oscillation of the sealed launch lasts shorter.
基金support from the National Natural Science Foundation of China(Nos.52206199,42176209,51979282,and 41676071)the Natural Science Foundation of Shandong Province(No.ZR2021MD064).
文摘Corrosion failure accidents owing to flow erosion and pipeline corrosion frequently occur during transportation.The welding reinforcement height(WRH)can induce locally micro-turbulent flow field,which aggravates local corrosion of welded joints.A high wall shear stress(WsS)experimental setup was established to conduct the online electrochemical corrosion test.The influence of WRH sizes on local corrosion of welded joints was studied at different flow rates.The electrochemical signals of the local corrosion of X80 welded joints at different flow rates were monitored in real time using electrochemical impedance spectroscopy and wire beam microelectrode.In addition,the corrosion products composition and properties were analyzed.The results show that the micro-turbulent flow fields induced by the WRHs can enhance ion mass transfer near the welded joints.The corrosion products on the WRH surface also present different microscopic morphologies at different flow rates.In strong flow fields,the locally enhanced wsS can peel off the dense corrosion product partially,leading to the electrochemical distribution of large cathode and small anode,which accelerates the occurrence and development processes of the local corrosion of welded joints.The scientific guidelines for the corrosion protection of long-distance oil and gas pipelines can be potentially provided.
