Microbial fouling is an important challenge in water recovery system of manned spacecrafts for longer term missions.Microbial fouling of 5A06 aluminium alloy induced by typical extreme environment-resistant bacteria i...Microbial fouling is an important challenge in water recovery system of manned spacecrafts for longer term missions.Microbial fouling of 5A06 aluminium alloy induced by typical extreme environment-resistant bacteria in oligotrophic solutions of simulated condensate of manned spacecraft was investigated.Bacillus cereus showed poor survival ability to oligotrophic environments,and a small amount of remaining live B.cereus cells mainly existed in the form of spores without forming biofilms.And when B.cereus was mixed cultured with Cupriavidus metallidurans,the system was mainly affected by C.metallidurans biofilms rather than B.cereus cells.C.metallidurans could promote the thickness of passive films of aluminum alloy,so C.metallidurans posed a minor threat to the corrosion of 5A06 aluminum alloy.However,C.metallidurans showed strong adaptability to oligotrophic environments and formed a large number of biofilms.And the contamination threat of C.metallidurans still dominated even cultured with B.cereus.Even when cultured with B.cereus,the threat of contamination from C.metallidurans still pre-dominates.Therefore,C.metallidurans would pose a threat of microbial fouling to the oligotrophic water recovery system of manned spacecrafts.展开更多
Objective： Coronary collateral circulation is an alternative source of blood supply to myocardium in the presence of advanced coronary artery disease. We sought to determine which clinical and angiographic variables ...Objective： Coronary collateral circulation is an alternative source of blood supply to myocardium in the presence of advanced coronary artery disease. We sought to determine which clinical and angiographic variables are associated with collateral development in patients with stable angina and chronic total coronary occlusion. Methods： Demographic variables, biochemical measurements, and angiographic findings were collected from 478 patients with stable angina and chronic total coronary occlusion. The presence and extent of collaterals supplying the distal aspect of a total coronary occlusion from the contra-lateral vessel were graded from 0 to 3 according to the Rentrop scoring system. Results： Low （Rentrop score of 0 or 1） and high （Rentrop score of 2 or 3） coronary collateralizations were detected in 186 and 292 patients, respectively. Despite similar age, cigarette smoking, and medical treatment, patients with low collateralization were female in a higher proportion and less hypertensive, and had higher rates of type 2 diabetes and dyslipidemia than those with high coUateralization （for all comparisons, P〈0.05）. In addition, patients with low collateralization exhibited more single-vessel disease, less right coronary artery occlusion, more impaired renal function, and higher serum levels of high-sensitivity C-reactive protein （hsCRP） compared with those with high col- lateralization. Multivariate analysis revealed that age of 〉65 years, female gender, diabetes, no history of hypertension dyslipidemia, moderate to severe renal dysfunction, single-vessel disease, and elevated hsCRP levels were inde- pendently associated with low coronary collateralization. Conclusions： Coronary collateralization was reduced in almost 40% of stable angina patients with chronic total occlusion, which was related to clinical and angiographic factors. The impact of coronary collateralization on outcomes after revascularization needs further investigation.展开更多
A rectangle crevice assembly was used to study the effects of cathodic protection （CP） potential, crevice thickness, holiday size, bubbling CO2, and surface condition on the chemical and electrochemical environment ...A rectangle crevice assembly was used to study the effects of cathodic protection （CP） potential, crevice thickness, holiday size, bubbling CO2, and surface condition on the chemical and electrochemical environment of the local solution under disbonded coatings. It is found that the cathodic protection removes dissolved oxygen from the crevice and thus shifts the solution to a more al- kaline state. Furthermore, the potential of the steel reaches the protected potential range. The available protection distance increases with the negative applying potential. The steady potential and pH distribution are easily achieved, but the polarization degree is not satisfied within the thinner crevice. The difference in the solution environment is found to correlate to the holiday size. The smaller the holiday, the smaller the difference is. The presence of CO2 inhibits the formation of an alkaline environment. It is also found that the rust layer dramatically decreases the polarization rate in the crevice.展开更多
The urgent need for immediate personal protection against chemical warfare agents(CWAs)spurs the requirement on robust and highly efficient catalytic systems that can be conveniently integrated to wearable devices.Her...The urgent need for immediate personal protection against chemical warfare agents(CWAs)spurs the requirement on robust and highly efficient catalytic systems that can be conveniently integrated to wearable devices.Herein,as a new concept for CWA decontamination catalyst design,sub-nanoscale,catalytically active zirconium-oxo molecular clusters are covalently integrated in flexible polymer network as crosslinkers for the full exposure of catalytic sites as well as robust framework structures.The obtained membrane catalysts exhibit high swelling ratio with aqueous content as 84 wt%and therefore,demonstrate quasi-homogeneous catalytic activity toward the rapid hydrolysis of both CWA,soman(GD)(t_(1/2)=5.0 min)and CWA simulant,methyl paraoxon(DMNP)(t_(1/2)=8.9 min).Meanwhile,due to the covalent nature of cross-linkages and the high flexibility of polymer strands,the membranes possess promising mechanical strength and toughness that can stand the impact of high gas pressures and show high permeation for both CO_(2)and O_(2),enabling their extended applications in the field of collective/personal protective materials with body comfort.展开更多
Purpose:To investigate how long indocyanine green (ICG) remains in the fundus after vitreoretinal surgery assisted with ICG,and to identify factors that influence the persistence duration.Methods:Fifty five eyes diagn...Purpose:To investigate how long indocyanine green (ICG) remains in the fundus after vitreoretinal surgery assisted with ICG,and to identify factors that influence the persistence duration.Methods:Fifty five eyes diagnosed as idiopathic macular hole (Stage 2 and 3) were randomly divided into five groups.ICG solution at concentrations of 5,2.5,2.5,1.25,and 0.5 mg/ml,employed in cases of Group I to V respectively,was applied to stain the internal limiting membrane(ILM) during the procedure of internal limiting membrane peeling..A prospective study was carried out after pars plana vitrectomy and ILM peeling were performed on 55 eyes with Stage 2,3,or 4 idiopathic macular holes..Infrared fundus pictures were obtained in all patients before and after surgery.Results:High levels of fluorescence from residual ICG (ICG hyperfluorescence) were mainly localized at the posterior pole of the fundus after surgery.In Group Ⅰ,Ⅱ,Ⅲ,Ⅳ and Ⅴ,the duration of persistence of flurorescence from ICG was 8.33±0.87,3.59±0.94,3.75±0.79,2.30±0.48,and 1.29±0.49 months,respectively.Although no significant difference was detected between Group Ⅱ and Group Ⅲ,the general inter-group difference was significant among the five groups in which different ICG concentration was applied.In Group Ⅲ,even though 90% of the macular holes acquired anatomical closure,ICG hyperfluorescence was detected in the macular area.Conclusion:ICG remains in the fundus for a period of months.The persistence duration of fluorescence from ICG is positively correlated with the concentration and the staining time of ICG.Hyaluronan is beneficial in reducing the amount of ICG residue in the macular area.展开更多
Persistent and maladaptive drug-related memories represent a key component in drug addiction.Converging evidence from both preclinical and clinical studies has demonstrated the potential efficacy of the memory reconso...Persistent and maladaptive drug-related memories represent a key component in drug addiction.Converging evidence from both preclinical and clinical studies has demonstrated the potential efficacy of the memory reconsolidation updating procedure(MRUP),a non-pharmacological strategy intertwining two distinct memory processes:reconsolidation and extinction—alternatively termed“the memory retrieval-extinction procedure”.This procedure presents a promising approach to attenuate,if not erase,entrenched drug memories and prevent relapse.The present review delineates the applications,molecular underpinnings,and operational boundaries of MRUP in the context of various forms of substance dependence.Furthermore,we critically examine the methodological limitations of MRUP,postulating potential refinement to optimize its therapeutic efficacy.In addition,we also look at the potential integration of MRUP and neurostimulation treatments in the domain of substance addiction.Overall,existing studies underscore the significant potential of MRUP,suggesting that interventions predicated on it could herald a promising avenue to enhance clinical outcomes in substance addiction therapy.展开更多
Psychiatric disorders constitute a complex health issue,primarily manifesting as significant disturbances in cognition,emotional regulation,and behavior.However,due to limited resources within health care systems,only...Psychiatric disorders constitute a complex health issue,primarily manifesting as significant disturbances in cognition,emotional regulation,and behavior.However,due to limited resources within health care systems,only a minority of patients can access effective treatment and care services,highlighting an urgent need for improvement.large language models(LLMs),with their natural language understanding and generation capabilities,are gradually penetrating the entire process of psychiatric diagnosis and treatment,including outpatient reception,diagnosis and therapy,clinical nursing,medication safety,and prognosis follow-up.They hold promise for improving the current severe shortage of health system resources and promoting equal access to mental health care.This article reviews the application scenarios and research progress of LLMs.It explores optimization methods for LLMs in psychiatry.Based on the research findings,we propose a clinical LLM for mental health using the Mixture of Experts framework to improve the accuracy of psychiatric diagnosis and therapeutic interventions.展开更多
BACKGROUND Brain-computer interface(BCI)technology is rapidly advancing in psychiatry.Informed consent competency(ICC)assessment among psychiatric patients is a pivotal concern in clinical research.AIM To analyze the ...BACKGROUND Brain-computer interface(BCI)technology is rapidly advancing in psychiatry.Informed consent competency(ICC)assessment among psychiatric patients is a pivotal concern in clinical research.AIM To analyze the assessment of ICC and form a framework with multi-dimensional elements involved in ICC of BCI clinical research among psychiatric disorders.METHODS A systematic review of studies regarding ICC assessments of BCI clinical research in patients with six kinds of psychiatric disorders was conducted.A systematic literature search was performed using PubMed,ScienceDirect,and Web of Science.Peer-reviewed articles and full-text studies were included in the analysis.There were no date restrictions,and all studies published up to February 27,2025,were included.RESULTS A total of 103 studies were selected for this review.Fifty-eight studies included ICC factors,and forty-five were classified in ICC related ethical issues of BCI research in six kinds of psychiatric disorders.Executive function impairment is widely recognized as the most significant factor impacting ICC,and processing speed deficits are observed in schizophrenia,mood disorders,and Alzheimer’s disease.Memory dysfunction,particularly episodic and working memory,contributes to compromised ICC.Five core ethical issues in BCI research should be addressed:BCI specificity,vulnerability,autonomy,dynamic ICC,comprehensiveness,and uncertainty.CONCLUSION A Five-Dimensional evaluative framework,including clinical,ethical,sociocultural,legal,and procedural dimensions,is constructed and proposed for future ICC research in BCI clinical research involving psychiatric disorders.展开更多
As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and el...As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and electrochemical characteristics,MXenes have shown great potential in brain-inspired neuromorphic computing electronics,including neuromorphic gas sensors,pressure sensors and photodetectors.This paper provides a forward-looking review of the research progress regarding MXenes in the neuromorphic sensing domain and discussed the critical challenges that need to be resolved.Key bottlenecks such as insufficient long-term stability under environmental exposure,high costs,scalability limitations in large-scale production,and mechanical mismatch in wearable integration hinder their practical deployment.Furthermore,unresolved issues like interfacial compatibility in heterostructures and energy inefficiency in neu-romorphic signal conversion demand urgent attention.The review offers insights into future research directions enhance the fundamental understanding of MXene properties and promote further integration into neuromorphic computing applications through the convergence with various emerging technologies.展开更多
BACKGROUND Patients with hypothalamic-pituitary disease have the feature of central obesity,insulin resistance, and dyslipidemia, and there is increased prevalence of liver dysfunction consistent with non-alcoholic fa...BACKGROUND Patients with hypothalamic-pituitary disease have the feature of central obesity,insulin resistance, and dyslipidemia, and there is increased prevalence of liver dysfunction consistent with non-alcoholic fatty liver disease(NAFLD) in this population. The causes of hypopituitarism in the reported studies varied and combined pituitary hormone deficiency including central diabetes insipidus is much common in this population. This retrospective cross-sectional study was performed to analyze the clinical characteristics and related factors with NAFLD and cirrhosis in Chinese adult hypopituitary/panhypopituitary patients.AIM To analyze the clinical characteristics of and related risk factors for NAFLD in Chinese adult hypopituitary patients.METHODS Adult Chinese patients with hypopituitarism and/or panhypopituitarism were enrolled at the Pituitary Center of Peking Union Medical College Hospitalbetween August 2012 and April 2018. According to abdominal ultrasonography,these patients were divided into an NAFLD(-) group and an NAFLD(+) group,and the latter was further divided into an NAFLD group and a cirrhotic group.The data, such as patient characteristics, diagnosis, and treatment, were extracted from medical records, and statistical analysis was performed.RESULTS A total of 36 male and 14 female adult Chinese patients with hypopituitarism were included in this retrospective study; 43(87.0%) of these patients exhibited growth hormone(GH) deficiency, and 39(78.3%) had diabetes insipidus. A total of 27(54.0%) patients were diagnosed with NAFLD, while seven patients were cirrhotic. No significant differences were noted in serum GH or insulin-like growth factor 1 among patients with cirrhosis, subjects with NAFLD, and those without NAFLD. However, plasma osmolality and serum sodium concentration of the cirrhotic patients were 314.9 mOsm/kgH2 O and 151.0 mmol/L,respectively, which were significantly higher than those of the NAFLD patients(P = 0.036 and 0.042, respectively). Overweight/obesity and insulin resistance were common metabolic disorders in this population. The body mass index(BMI)and homeostasis model assessment of insulin resistance parameters of the cirrhotic patients were 27.7 kg/m2 and 9.57, respectively, which were significantly higher than those of the patients without NAFLD(P = 0.011 and0.044, respectively). A correlation analysis was performed, and fasting insulin concentration was positively associated with plasma osmolality in patients with NAFLD, after adjusting for gender, age, and BMI(r = 0.540, P = 0.046), but no correlation was noted in patients without NAFLD.CONCLUSION NAFLD is common in patients with hypopituitarism. Plasma osmolality and serum sodium levels of hypopituitary patients with cirrhosis are higher than those of subjects with NAFLD, and fasting insulin concentration is positively associated with plasma osmolality in patients with NAFLD, which suggests that hyperosmolality might be a contributor to the worsening of NAFLD in hypopituitary patients.展开更多
Objective:Advanced glycation end-products (AGEs) exert inflammatory and oxidative stress insults to produce diabetic nephropathy mainly through the receptor for AGEs (RAGE).This study aimed to assess the effect of ato...Objective:Advanced glycation end-products (AGEs) exert inflammatory and oxidative stress insults to produce diabetic nephropathy mainly through the receptor for AGEs (RAGE).This study aimed to assess the effect of atorvastatin on diabetic nephropathy via soluble RAGE (sRAGE) and RAGE expressions in the rat kidney.Methods:Thirty-two male Sprague-Dawley rats were divided into four groups based on the presence or absence of streptozotocin-induced diabetes with or without atorvastatin treatment (10 mg/kg for 24 weeks).Serum sRAGE and glycated albumin (GA) levels were measured with enzyme-linked immunosorbent assay (ELISA) and improved bromocresol purple methods.Renal AGEs,RAGE,endogenous secretory RAGE (esRAGE),and sRAGE were determined with reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.Results:Mesangial expansion and microalbuminuria were aggravated in diabetic rats,and improved with atorvastatin treatment.Serum sRAGE levels were lower in diabetic than in normal rats.After atorvastatin treatment,serum and renal sRAGE levels were up-regulated,while renal RAGE expression was decreased in diabetic rats,associated with a reduction in accumulation of AGEs,though renal esRAGE mRNA expression was not significantly increased.Conclusions:Atorvastatin exerted a beneficial effect on diabetic nephropathy with reduced AGE accumulation,down-regulating RAGE expression and up-regulating sRAGE in the kidney.展开更多
To identify risk factors for HIV infection among men who have sex with men （MSM） and to provide a theoretical basis for prevention interventions. Between December 2011 and August 2012, a case-control study was condu...To identify risk factors for HIV infection among men who have sex with men （MSM） and to provide a theoretical basis for prevention interventions. Between December 2011 and August 2012, a case-control study was conducted among MSM who underwent voluntary counselling and testing for HIV. Confirmed HIV-positive MSM were included in the case group, and HIV-negative MSM were included in the control group. Information on possible risk factors was collected by a survey questionnaire and a qualitative interview. The results of a conditional logistic regression showed that the following were influencing factors for HIV infection： average monthly income between 2001 and 3000 Yuan （odds ratio （0R）=6.341, 95% Ch 1.714-12.544）, only sometimes using condoms when having anal sex with men in the last 6 months （0R=7.601, 95% Ch 1.359-23.083）, having HIV-positive sex partners （0R=5.273, 95% Ch 1.572- 17.691）, rectal trauma with bleeding in the last 6 months （0R=2.947, 95% Ch 1.308-6.638）, not using condoms at last sexual encounter （OR-- 1.278, 95% Ch 1.012-5.595）, engaging in commercial sex （0R=5.925, 95% Ch 1.923-13.890） and having more than 16 sex partners in the last 6 months （0R=1.175, 95% Ch 1.021-1.353）. These seven factors were the risk factors of HIV infection （OR〉l）. However, having anal sex less than 10 times in the previous 1 month （OR=O.O02, 95% CI： 0.000-0.287） was a protective factor against HIV infection among MSM （OR〈l）, and insertive （0R=0.116, 95% Ch 0.000-0.236） （OR〈l） anal intercourse influenced HIV infection. Interventions should be targeted at MSM whose average monthly income is between 2001 and 3000 Yuan, and who engage in commercial sex. In addition, the importance of using condoms at every sexual encounter should be emphasised in health education, as should the treatment of rectal trauma with bleeding. Finally, MSM should decrease the number of sex partners and frequency of anal sex to decrease the rate of HIV infection.展开更多
Sharp eyespot,mainly caused by the soil-borne fungus Rhizoctonia cerealis,affects wheat(Triticum aestivum L.)production worldwide.In this study,we isolated TaCML36 gene encoding a wheat calmodulin-like protein,and stu...Sharp eyespot,mainly caused by the soil-borne fungus Rhizoctonia cerealis,affects wheat(Triticum aestivum L.)production worldwide.In this study,we isolated TaCML36 gene encoding a wheat calmodulin-like protein,and studied its defense role in protection against R.cerealis.Transcription of TaCML36 was significantly elevated by both R.cerealis infection and exogenous ethylene treatment.Transcription was higher in resistant wheat lines than in susceptible ones.There were copies of TaCML36 on chromosomes 5A,5B,and 5D.The TaCML36 protein is composed of 183 amino acids and contains two calcium-binding EFhand domains.Subcellular localization assays in wheat indicated that TaCML36 localizes in both the cytoplasm and nucleus.Virus-induced gene silencing and disease assessment indicated that compared to the controls,TaCML36-silenced wheat plants displayed significantly reduced resistance to R.cerealis and had greater fungal biomass,suggesting that knockdown of TaCML36 impaired host resistance.Knockdown of TaCML36 also significantly repressed expression of pathogenesis-related genes such as Chitinase 1,PDF35,and PR17C,the ethylene response factor-encoding gene TaPIE1,and ethylene biosynthesis gene ACO2.Collectively,our results suggest that TaCML36 positively participates in the innate immune response to R.cerealis infection by modulating expression of defense-associated genes possibly in the ethylene signaling pathway.展开更多
Objective To evaluate the clinical and pathological features of Riedel's thyroiditis(RT),and current diagnostic and treatment methods for that disease.Methods Five RT cases identified by surgery and pathological e...Objective To evaluate the clinical and pathological features of Riedel's thyroiditis(RT),and current diagnostic and treatment methods for that disease.Methods Five RT cases identified by surgery and pathological examinations at Peking Union Medical College Hospital from 1985 to 2009 were analyzed and compared with the cases reported in the literature in terms of clinical and pathological features.Immunohistochemical staining of kappa and lambda light chains was carried out for RT tissues from all the five patients.Results All the five cases were females,aged 45-55 years.Elevation of serum thyroid autoantibodies was found in only one patient,who had longer disease duration than the others.Pathological examination revealed invasive fibrosclerosis of the thyroid follicles,thyroid capsule,and the surrounding tissues.In RT tissues,the number of cells containing lambda chains was a little higher than those containing kappa chains.Conclusions RT is a rare disease which might be more common in middle-aged females than in other populations.Pathological features include the destruction of thyroid follicle,extension into surrounding tissues by inflammatory cells and fibrous tissues.Immunohistochemical staining of kappa and lambda chains could help diagnose RT.展开更多
Temper rolling,as a final manufacturing procedure,brings the change of surface features and hence affects the corrosion behaviors of interstitial-free(IF)steel.This study investigates changes in residual stress,micros...Temper rolling,as a final manufacturing procedure,brings the change of surface features and hence affects the corrosion behaviors of interstitial-free(IF)steel.This study investigates changes in residual stress,microstructure,and surface topography of IF steel using X-ray diffraction,electron backscatter diffraction,and optical interferometric microscopy.And the synthetic influence of surface features on the corrosion process of the steel was evaluated by damp heat tests and electrochemical measurements.Results showed that low tensile and compressive residual stresses are introduced to the surface of the IF steel.Some grains had a grain orientation spread(GOS)value greater than 0.50 after temper rolling.Moreover,temper rolling caused a slight change in the surface profile of the IF steel.The compressive residual stress had an overwhelming role at the macroscopic level,in retarding the corrosion evolution process of IF steel,as well as in decreasing the average corrosion rate.And corrosion was more likely to initiate and propagate in matrices with a high GOS value,which played the determinant role at the microscopic level.Moreover,the depth of valley in the surface profile could affect the diffusion process involved in the electrode reactions,which was more likely to exert an extra influence on the corrosion rate of IF steel.展开更多
This work aimed to study the comprehensive effects of photo-oxidation and biodegradation on different failure stages of polyester coatings,which were exposed to the tropical rainforest atmosphere.The surface morpholog...This work aimed to study the comprehensive effects of photo-oxidation and biodegradation on different failure stages of polyester coatings,which were exposed to the tropical rainforest atmosphere.The surface morphology,aging products,local aging characteristics and electrochemical behavior of the coatings were characterized with scanning electron microscope(SEM),fourier transform infrared spectroscopy(FTIR),electrochemical impedance spectroscopy(EIS)and high-resolution dispersive Raman microscope.The results showed that the surface of coatings became rougher and fungal hyphae distributed more densely on surface with the increasing of exposure time.From the aspect of polymer structure,the ultraviolet radiation destroyed the main chain of polyester through the photo-oxidation process,resulting in the breakage of aliphatic ester bonds and the formation of esters.Further,the metabolites of fungi can promote the hydrolysis of oligomers produced by the photo-oxidation.In a short,the photo-oxidation could facilitate the biodegradation of the coating.With the synergistic effect of UV photo-oxidation and fungal biodegradation,a rapid diffusion tunnel between the coating surface and the metal substrate was established at the pore defects of the coating,which finally accelerated the corrosion failure process of the coating.The main corrosion products includeα-Fe_(2)O_(3),ZnO and Zn_(5)(OH)_(6)(CO_(3))_(2).展开更多
Fluid flow past twin circular cylinders in a tandem arrangement placed near a plane wall was investigated by means of numerical simulations. The two-dimensional Navier-Stokes equations were solved with a three-step fi...Fluid flow past twin circular cylinders in a tandem arrangement placed near a plane wall was investigated by means of numerical simulations. The two-dimensional Navier-Stokes equations were solved with a three-step finite element method at a relatively low Reynolds number of Re -- 200 for various dimensionless ratios of 0.25 ≤ G/D ≤2.0 and 1.0 ≤ L/D ≤ 4.0, where D is the cylinder diameter, L is the center-to-center distance between the two cylinders, and G is the gap between the lowest surface of the twin cylinders and the plane wall. The influences of G/D and L/D on the hydrodynamic force coefficients, Strouhal numbers, and vortex shedding modes were examined. Three different vortex shedding modes of the near wake were identified according to the numerical results. It was found that the hydrodynamic force coefficients and vortex shedding modes are quite different with respect to various combinations of G/D and L/D. For very small values of G/D, the vortex shedding is completely suppressed, resulting in the root mean square （RMS） values of drag and lift coefficients of both cylinders and the Strouhal number for the downstream cylinder being almost zero. The mean drag coefficient of the upstream cylinder is larger than that of the downstream cylinder for the same combination of G/D and L/D. It is also observed that change in the vortex shedding modes leads to a significant increase in the RMS values of drag and lift coefficients.展开更多
The anodic dissolution process of a crack tip at 2024-T351 aluminium alloy （AA2024-T351） was determined by means of scanning Kelvin probe （SKP）. Wedge-open loading （WOL） specimens were immersed in a 3.5wt% NaCl ...The anodic dissolution process of a crack tip at 2024-T351 aluminium alloy （AA2024-T351） was determined by means of scanning Kelvin probe （SKP）. Wedge-open loading （WOL） specimens were immersed in a 3.5wt% NaCl solution. After various durations of immersion, the Volta potential distributions around the crack were measured by SKP and the surface morphologies were observed by scanning electron microscopy （SEM）. It is found that there is a nonuniform distribution of Volta potential around the crack. Before immersion, the Volta potential at crack tip is more negative than that in other regions. However, after immersion, a converse result occurs with the most positive Volta potential measured at the crack tip. SEM observations demonstrate that the noticeable positive shift of Volta potential results fi：om the formation of corrosion products which deposit around the crack tip. Energy-dispersive spectrometry （EDS） analysis shows that the corrosion products are mainly A1 oxide and Cu-rich particles. These observations implicate that the applied stress contributes to the preferential anodic dissolution of the crack tip and the redistribution of Cu.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51971032,52371048,and 52071019).
文摘Microbial fouling is an important challenge in water recovery system of manned spacecrafts for longer term missions.Microbial fouling of 5A06 aluminium alloy induced by typical extreme environment-resistant bacteria in oligotrophic solutions of simulated condensate of manned spacecraft was investigated.Bacillus cereus showed poor survival ability to oligotrophic environments,and a small amount of remaining live B.cereus cells mainly existed in the form of spores without forming biofilms.And when B.cereus was mixed cultured with Cupriavidus metallidurans,the system was mainly affected by C.metallidurans biofilms rather than B.cereus cells.C.metallidurans could promote the thickness of passive films of aluminum alloy,so C.metallidurans posed a minor threat to the corrosion of 5A06 aluminum alloy.However,C.metallidurans showed strong adaptability to oligotrophic environments and formed a large number of biofilms.And the contamination threat of C.metallidurans still dominated even cultured with B.cereus.Even when cultured with B.cereus,the threat of contamination from C.metallidurans still pre-dominates.Therefore,C.metallidurans would pose a threat of microbial fouling to the oligotrophic water recovery system of manned spacecrafts.
文摘Objective： Coronary collateral circulation is an alternative source of blood supply to myocardium in the presence of advanced coronary artery disease. We sought to determine which clinical and angiographic variables are associated with collateral development in patients with stable angina and chronic total coronary occlusion. Methods： Demographic variables, biochemical measurements, and angiographic findings were collected from 478 patients with stable angina and chronic total coronary occlusion. The presence and extent of collaterals supplying the distal aspect of a total coronary occlusion from the contra-lateral vessel were graded from 0 to 3 according to the Rentrop scoring system. Results： Low （Rentrop score of 0 or 1） and high （Rentrop score of 2 or 3） coronary collateralizations were detected in 186 and 292 patients, respectively. Despite similar age, cigarette smoking, and medical treatment, patients with low collateralization were female in a higher proportion and less hypertensive, and had higher rates of type 2 diabetes and dyslipidemia than those with high coUateralization （for all comparisons, P〈0.05）. In addition, patients with low collateralization exhibited more single-vessel disease, less right coronary artery occlusion, more impaired renal function, and higher serum levels of high-sensitivity C-reactive protein （hsCRP） compared with those with high col- lateralization. Multivariate analysis revealed that age of 〉65 years, female gender, diabetes, no history of hypertension dyslipidemia, moderate to severe renal dysfunction, single-vessel disease, and elevated hsCRP levels were inde- pendently associated with low coronary collateralization. Conclusions： Coronary collateralization was reduced in almost 40% of stable angina patients with chronic total occlusion, which was related to clinical and angiographic factors. The impact of coronary collateralization on outcomes after revascularization needs further investigation.
基金supported by the National Science & Technology Infrastructure Development Program of China (No.2005DKA10400)
文摘A rectangle crevice assembly was used to study the effects of cathodic protection （CP） potential, crevice thickness, holiday size, bubbling CO2, and surface condition on the chemical and electrochemical environment of the local solution under disbonded coatings. It is found that the cathodic protection removes dissolved oxygen from the crevice and thus shifts the solution to a more al- kaline state. Furthermore, the potential of the steel reaches the protected potential range. The available protection distance increases with the negative applying potential. The steady potential and pH distribution are easily achieved, but the polarization degree is not satisfied within the thinner crevice. The difference in the solution environment is found to correlate to the holiday size. The smaller the holiday, the smaller the difference is. The presence of CO2 inhibits the formation of an alkaline environment. It is also found that the rust layer dramatically decreases the polarization rate in the crevice.
基金the National Key Research and Development Program of China(No.2018YFB0704200)the Project of State Key Laboratory of NBC Protection for Civilian(No.ZKGSG-ZB-20194334)+1 种基金the National Natural Science Foundation of China(Nos.21961142018 and 51873067)Natural Science Foundation of Guangdong Province(Nos.2021A1515012024 and 2021A1515010271)。
文摘The urgent need for immediate personal protection against chemical warfare agents(CWAs)spurs the requirement on robust and highly efficient catalytic systems that can be conveniently integrated to wearable devices.Herein,as a new concept for CWA decontamination catalyst design,sub-nanoscale,catalytically active zirconium-oxo molecular clusters are covalently integrated in flexible polymer network as crosslinkers for the full exposure of catalytic sites as well as robust framework structures.The obtained membrane catalysts exhibit high swelling ratio with aqueous content as 84 wt%and therefore,demonstrate quasi-homogeneous catalytic activity toward the rapid hydrolysis of both CWA,soman(GD)(t_(1/2)=5.0 min)and CWA simulant,methyl paraoxon(DMNP)(t_(1/2)=8.9 min).Meanwhile,due to the covalent nature of cross-linkages and the high flexibility of polymer strands,the membranes possess promising mechanical strength and toughness that can stand the impact of high gas pressures and show high permeation for both CO_(2)and O_(2),enabling their extended applications in the field of collective/personal protective materials with body comfort.
文摘Purpose:To investigate how long indocyanine green (ICG) remains in the fundus after vitreoretinal surgery assisted with ICG,and to identify factors that influence the persistence duration.Methods:Fifty five eyes diagnosed as idiopathic macular hole (Stage 2 and 3) were randomly divided into five groups.ICG solution at concentrations of 5,2.5,2.5,1.25,and 0.5 mg/ml,employed in cases of Group I to V respectively,was applied to stain the internal limiting membrane(ILM) during the procedure of internal limiting membrane peeling..A prospective study was carried out after pars plana vitrectomy and ILM peeling were performed on 55 eyes with Stage 2,3,or 4 idiopathic macular holes..Infrared fundus pictures were obtained in all patients before and after surgery.Results:High levels of fluorescence from residual ICG (ICG hyperfluorescence) were mainly localized at the posterior pole of the fundus after surgery.In Group Ⅰ,Ⅱ,Ⅲ,Ⅳ and Ⅴ,the duration of persistence of flurorescence from ICG was 8.33±0.87,3.59±0.94,3.75±0.79,2.30±0.48,and 1.29±0.49 months,respectively.Although no significant difference was detected between Group Ⅱ and Group Ⅲ,the general inter-group difference was significant among the five groups in which different ICG concentration was applied.In Group Ⅲ,even though 90% of the macular holes acquired anatomical closure,ICG hyperfluorescence was detected in the macular area.Conclusion:ICG remains in the fundus for a period of months.The persistence duration of fluorescence from ICG is positively correlated with the concentration and the staining time of ICG.Hyaluronan is beneficial in reducing the amount of ICG residue in the macular area.
基金supported by the National Natural Science Foundation of China(82071498,81871046,and 32161143022)STI2030-Major Projects(2022ZD0214500).
文摘Persistent and maladaptive drug-related memories represent a key component in drug addiction.Converging evidence from both preclinical and clinical studies has demonstrated the potential efficacy of the memory reconsolidation updating procedure(MRUP),a non-pharmacological strategy intertwining two distinct memory processes:reconsolidation and extinction—alternatively termed“the memory retrieval-extinction procedure”.This procedure presents a promising approach to attenuate,if not erase,entrenched drug memories and prevent relapse.The present review delineates the applications,molecular underpinnings,and operational boundaries of MRUP in the context of various forms of substance dependence.Furthermore,we critically examine the methodological limitations of MRUP,postulating potential refinement to optimize its therapeutic efficacy.In addition,we also look at the potential integration of MRUP and neurostimulation treatments in the domain of substance addiction.Overall,existing studies underscore the significant potential of MRUP,suggesting that interventions predicated on it could herald a promising avenue to enhance clinical outcomes in substance addiction therapy.
基金Supported by the STI2030-Major Projects,No.2021ZD0203400 and No.2021ZD0200800the National Natural Science Foundation of China,No.82171477。
文摘Psychiatric disorders constitute a complex health issue,primarily manifesting as significant disturbances in cognition,emotional regulation,and behavior.However,due to limited resources within health care systems,only a minority of patients can access effective treatment and care services,highlighting an urgent need for improvement.large language models(LLMs),with their natural language understanding and generation capabilities,are gradually penetrating the entire process of psychiatric diagnosis and treatment,including outpatient reception,diagnosis and therapy,clinical nursing,medication safety,and prognosis follow-up.They hold promise for improving the current severe shortage of health system resources and promoting equal access to mental health care.This article reviews the application scenarios and research progress of LLMs.It explores optimization methods for LLMs in psychiatry.Based on the research findings,we propose a clinical LLM for mental health using the Mixture of Experts framework to improve the accuracy of psychiatric diagnosis and therapeutic interventions.
基金Supported by the Ministry of Science and Technology of the People's Republic of China(2021ZD0201900)Project 5,No.2021ZD0201905Capital’s Funds for Health Improvement and Research,No.CFH 2022-2-4115.
文摘BACKGROUND Brain-computer interface(BCI)technology is rapidly advancing in psychiatry.Informed consent competency(ICC)assessment among psychiatric patients is a pivotal concern in clinical research.AIM To analyze the assessment of ICC and form a framework with multi-dimensional elements involved in ICC of BCI clinical research among psychiatric disorders.METHODS A systematic review of studies regarding ICC assessments of BCI clinical research in patients with six kinds of psychiatric disorders was conducted.A systematic literature search was performed using PubMed,ScienceDirect,and Web of Science.Peer-reviewed articles and full-text studies were included in the analysis.There were no date restrictions,and all studies published up to February 27,2025,were included.RESULTS A total of 103 studies were selected for this review.Fifty-eight studies included ICC factors,and forty-five were classified in ICC related ethical issues of BCI research in six kinds of psychiatric disorders.Executive function impairment is widely recognized as the most significant factor impacting ICC,and processing speed deficits are observed in schizophrenia,mood disorders,and Alzheimer’s disease.Memory dysfunction,particularly episodic and working memory,contributes to compromised ICC.Five core ethical issues in BCI research should be addressed:BCI specificity,vulnerability,autonomy,dynamic ICC,comprehensiveness,and uncertainty.CONCLUSION A Five-Dimensional evaluative framework,including clinical,ethical,sociocultural,legal,and procedural dimensions,is constructed and proposed for future ICC research in BCI clinical research involving psychiatric disorders.
基金supported by the NSFC(12474071)Natural Science Foundation of Shandong Province(ZR2024YQ051,ZR2025QB50)+6 种基金Guangdong Basic and Applied Basic Research Foundation(2025A1515011191)the Shanghai Sailing Program(23YF1402200,23YF1402400)funded by Basic Research Program of Jiangsu(BK20240424)Open Research Fund of State Key Laboratory of Crystal Materials(KF2406)Taishan Scholar Foundation of Shandong Province(tsqn202408006,tsqn202507058)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTB002)the Qilu Young Scholar Program of Shandong University。
文摘As emerging two-dimensional(2D)materials,carbides and nitrides(MXenes)could be solid solutions or organized structures made up of multi-atomic layers.With remarkable and adjustable electrical,optical,mechanical,and electrochemical characteristics,MXenes have shown great potential in brain-inspired neuromorphic computing electronics,including neuromorphic gas sensors,pressure sensors and photodetectors.This paper provides a forward-looking review of the research progress regarding MXenes in the neuromorphic sensing domain and discussed the critical challenges that need to be resolved.Key bottlenecks such as insufficient long-term stability under environmental exposure,high costs,scalability limitations in large-scale production,and mechanical mismatch in wearable integration hinder their practical deployment.Furthermore,unresolved issues like interfacial compatibility in heterostructures and energy inefficiency in neu-romorphic signal conversion demand urgent attention.The review offers insights into future research directions enhance the fundamental understanding of MXene properties and promote further integration into neuromorphic computing applications through the convergence with various emerging technologies.
基金Supported by the National Key Program of Clinical Science,No.WBYZ 2011-873the Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences,No.2016YFC0901500the Special Research Fund for Central Universities,Peking Union Medical College,No.2017PT31004
文摘BACKGROUND Patients with hypothalamic-pituitary disease have the feature of central obesity,insulin resistance, and dyslipidemia, and there is increased prevalence of liver dysfunction consistent with non-alcoholic fatty liver disease(NAFLD) in this population. The causes of hypopituitarism in the reported studies varied and combined pituitary hormone deficiency including central diabetes insipidus is much common in this population. This retrospective cross-sectional study was performed to analyze the clinical characteristics and related factors with NAFLD and cirrhosis in Chinese adult hypopituitary/panhypopituitary patients.AIM To analyze the clinical characteristics of and related risk factors for NAFLD in Chinese adult hypopituitary patients.METHODS Adult Chinese patients with hypopituitarism and/or panhypopituitarism were enrolled at the Pituitary Center of Peking Union Medical College Hospitalbetween August 2012 and April 2018. According to abdominal ultrasonography,these patients were divided into an NAFLD(-) group and an NAFLD(+) group,and the latter was further divided into an NAFLD group and a cirrhotic group.The data, such as patient characteristics, diagnosis, and treatment, were extracted from medical records, and statistical analysis was performed.RESULTS A total of 36 male and 14 female adult Chinese patients with hypopituitarism were included in this retrospective study; 43(87.0%) of these patients exhibited growth hormone(GH) deficiency, and 39(78.3%) had diabetes insipidus. A total of 27(54.0%) patients were diagnosed with NAFLD, while seven patients were cirrhotic. No significant differences were noted in serum GH or insulin-like growth factor 1 among patients with cirrhosis, subjects with NAFLD, and those without NAFLD. However, plasma osmolality and serum sodium concentration of the cirrhotic patients were 314.9 mOsm/kgH2 O and 151.0 mmol/L,respectively, which were significantly higher than those of the NAFLD patients(P = 0.036 and 0.042, respectively). Overweight/obesity and insulin resistance were common metabolic disorders in this population. The body mass index(BMI)and homeostasis model assessment of insulin resistance parameters of the cirrhotic patients were 27.7 kg/m2 and 9.57, respectively, which were significantly higher than those of the patients without NAFLD(P = 0.011 and0.044, respectively). A correlation analysis was performed, and fasting insulin concentration was positively associated with plasma osmolality in patients with NAFLD, after adjusting for gender, age, and BMI(r = 0.540, P = 0.046), but no correlation was noted in patients without NAFLD.CONCLUSION NAFLD is common in patients with hypopituitarism. Plasma osmolality and serum sodium levels of hypopituitary patients with cirrhosis are higher than those of subjects with NAFLD, and fasting insulin concentration is positively associated with plasma osmolality in patients with NAFLD, which suggests that hyperosmolality might be a contributor to the worsening of NAFLD in hypopituitary patients.
文摘Objective:Advanced glycation end-products (AGEs) exert inflammatory and oxidative stress insults to produce diabetic nephropathy mainly through the receptor for AGEs (RAGE).This study aimed to assess the effect of atorvastatin on diabetic nephropathy via soluble RAGE (sRAGE) and RAGE expressions in the rat kidney.Methods:Thirty-two male Sprague-Dawley rats were divided into four groups based on the presence or absence of streptozotocin-induced diabetes with or without atorvastatin treatment (10 mg/kg for 24 weeks).Serum sRAGE and glycated albumin (GA) levels were measured with enzyme-linked immunosorbent assay (ELISA) and improved bromocresol purple methods.Renal AGEs,RAGE,endogenous secretory RAGE (esRAGE),and sRAGE were determined with reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting.Results:Mesangial expansion and microalbuminuria were aggravated in diabetic rats,and improved with atorvastatin treatment.Serum sRAGE levels were lower in diabetic than in normal rats.After atorvastatin treatment,serum and renal sRAGE levels were up-regulated,while renal RAGE expression was decreased in diabetic rats,associated with a reduction in accumulation of AGEs,though renal esRAGE mRNA expression was not significantly increased.Conclusions:Atorvastatin exerted a beneficial effect on diabetic nephropathy with reduced AGE accumulation,down-regulating RAGE expression and up-regulating sRAGE in the kidney.
文摘To identify risk factors for HIV infection among men who have sex with men （MSM） and to provide a theoretical basis for prevention interventions. Between December 2011 and August 2012, a case-control study was conducted among MSM who underwent voluntary counselling and testing for HIV. Confirmed HIV-positive MSM were included in the case group, and HIV-negative MSM were included in the control group. Information on possible risk factors was collected by a survey questionnaire and a qualitative interview. The results of a conditional logistic regression showed that the following were influencing factors for HIV infection： average monthly income between 2001 and 3000 Yuan （odds ratio （0R）=6.341, 95% Ch 1.714-12.544）, only sometimes using condoms when having anal sex with men in the last 6 months （0R=7.601, 95% Ch 1.359-23.083）, having HIV-positive sex partners （0R=5.273, 95% Ch 1.572- 17.691）, rectal trauma with bleeding in the last 6 months （0R=2.947, 95% Ch 1.308-6.638）, not using condoms at last sexual encounter （OR-- 1.278, 95% Ch 1.012-5.595）, engaging in commercial sex （0R=5.925, 95% Ch 1.923-13.890） and having more than 16 sex partners in the last 6 months （0R=1.175, 95% Ch 1.021-1.353）. These seven factors were the risk factors of HIV infection （OR〉l）. However, having anal sex less than 10 times in the previous 1 month （OR=O.O02, 95% CI： 0.000-0.287） was a protective factor against HIV infection among MSM （OR〈l）, and insertive （0R=0.116, 95% Ch 0.000-0.236） （OR〈l） anal intercourse influenced HIV infection. Interventions should be targeted at MSM whose average monthly income is between 2001 and 3000 Yuan, and who engage in commercial sex. In addition, the importance of using condoms at every sexual encounter should be emphasised in health education, as should the treatment of rectal trauma with bleeding. Finally, MSM should decrease the number of sex partners and frequency of anal sex to decrease the rate of HIV infection.
基金funded by the National “Key Sci-Tech” Project (2016ZX08002-001-004)
文摘Sharp eyespot,mainly caused by the soil-borne fungus Rhizoctonia cerealis,affects wheat(Triticum aestivum L.)production worldwide.In this study,we isolated TaCML36 gene encoding a wheat calmodulin-like protein,and studied its defense role in protection against R.cerealis.Transcription of TaCML36 was significantly elevated by both R.cerealis infection and exogenous ethylene treatment.Transcription was higher in resistant wheat lines than in susceptible ones.There were copies of TaCML36 on chromosomes 5A,5B,and 5D.The TaCML36 protein is composed of 183 amino acids and contains two calcium-binding EFhand domains.Subcellular localization assays in wheat indicated that TaCML36 localizes in both the cytoplasm and nucleus.Virus-induced gene silencing and disease assessment indicated that compared to the controls,TaCML36-silenced wheat plants displayed significantly reduced resistance to R.cerealis and had greater fungal biomass,suggesting that knockdown of TaCML36 impaired host resistance.Knockdown of TaCML36 also significantly repressed expression of pathogenesis-related genes such as Chitinase 1,PDF35,and PR17C,the ethylene response factor-encoding gene TaPIE1,and ethylene biosynthesis gene ACO2.Collectively,our results suggest that TaCML36 positively participates in the innate immune response to R.cerealis infection by modulating expression of defense-associated genes possibly in the ethylene signaling pathway.
文摘Objective To evaluate the clinical and pathological features of Riedel's thyroiditis(RT),and current diagnostic and treatment methods for that disease.Methods Five RT cases identified by surgery and pathological examinations at Peking Union Medical College Hospital from 1985 to 2009 were analyzed and compared with the cases reported in the literature in terms of clinical and pathological features.Immunohistochemical staining of kappa and lambda light chains was carried out for RT tissues from all the five patients.Results All the five cases were females,aged 45-55 years.Elevation of serum thyroid autoantibodies was found in only one patient,who had longer disease duration than the others.Pathological examination revealed invasive fibrosclerosis of the thyroid follicles,thyroid capsule,and the surrounding tissues.In RT tissues,the number of cells containing lambda chains was a little higher than those containing kappa chains.Conclusions RT is a rare disease which might be more common in middle-aged females than in other populations.Pathological features include the destruction of thyroid follicle,extension into surrounding tissues by inflammatory cells and fibrous tissues.Immunohistochemical staining of kappa and lambda chains could help diagnose RT.
基金financially supported by the National Key Research and Development Program of China(No.2018YFB0605502)National Natural Science Foundation of China(No.U1560104)the State Key Laboratory of Metal Material for Marine Equipment and Application and National Environmental Corrosion Platform(NECP)。
文摘Temper rolling,as a final manufacturing procedure,brings the change of surface features and hence affects the corrosion behaviors of interstitial-free(IF)steel.This study investigates changes in residual stress,microstructure,and surface topography of IF steel using X-ray diffraction,electron backscatter diffraction,and optical interferometric microscopy.And the synthetic influence of surface features on the corrosion process of the steel was evaluated by damp heat tests and electrochemical measurements.Results showed that low tensile and compressive residual stresses are introduced to the surface of the IF steel.Some grains had a grain orientation spread(GOS)value greater than 0.50 after temper rolling.Moreover,temper rolling caused a slight change in the surface profile of the IF steel.The compressive residual stress had an overwhelming role at the macroscopic level,in retarding the corrosion evolution process of IF steel,as well as in decreasing the average corrosion rate.And corrosion was more likely to initiate and propagate in matrices with a high GOS value,which played the determinant role at the microscopic level.Moreover,the depth of valley in the surface profile could affect the diffusion process involved in the electrode reactions,which was more likely to exert an extra influence on the corrosion rate of IF steel.
基金financially supported by the National Key R&D Program of China(No.2018YFB0605502)the National Natural Science Foundation of China(No.U1560104)the National Environmental Corrosion Platform(NECP)。
文摘This work aimed to study the comprehensive effects of photo-oxidation and biodegradation on different failure stages of polyester coatings,which were exposed to the tropical rainforest atmosphere.The surface morphology,aging products,local aging characteristics and electrochemical behavior of the coatings were characterized with scanning electron microscope(SEM),fourier transform infrared spectroscopy(FTIR),electrochemical impedance spectroscopy(EIS)and high-resolution dispersive Raman microscope.The results showed that the surface of coatings became rougher and fungal hyphae distributed more densely on surface with the increasing of exposure time.From the aspect of polymer structure,the ultraviolet radiation destroyed the main chain of polyester through the photo-oxidation process,resulting in the breakage of aliphatic ester bonds and the formation of esters.Further,the metabolites of fungi can promote the hydrolysis of oligomers produced by the photo-oxidation.In a short,the photo-oxidation could facilitate the biodegradation of the coating.With the synergistic effect of UV photo-oxidation and fungal biodegradation,a rapid diffusion tunnel between the coating surface and the metal substrate was established at the pore defects of the coating,which finally accelerated the corrosion failure process of the coating.The main corrosion products includeα-Fe_(2)O_(3),ZnO and Zn_(5)(OH)_(6)(CO_(3))_(2).
基金supported by the National Natural Science Foundation of China(Grants No.51409035,51279029,and 51490673)the Open Fund from the Key Laboratory of Harbor,Waterway and Sedimentation Engineering of Ministry of Communications,Nanjing Hydraulic Research Institute
文摘Fluid flow past twin circular cylinders in a tandem arrangement placed near a plane wall was investigated by means of numerical simulations. The two-dimensional Navier-Stokes equations were solved with a three-step finite element method at a relatively low Reynolds number of Re -- 200 for various dimensionless ratios of 0.25 ≤ G/D ≤2.0 and 1.0 ≤ L/D ≤ 4.0, where D is the cylinder diameter, L is the center-to-center distance between the two cylinders, and G is the gap between the lowest surface of the twin cylinders and the plane wall. The influences of G/D and L/D on the hydrodynamic force coefficients, Strouhal numbers, and vortex shedding modes were examined. Three different vortex shedding modes of the near wake were identified according to the numerical results. It was found that the hydrodynamic force coefficients and vortex shedding modes are quite different with respect to various combinations of G/D and L/D. For very small values of G/D, the vortex shedding is completely suppressed, resulting in the root mean square （RMS） values of drag and lift coefficients of both cylinders and the Strouhal number for the downstream cylinder being almost zero. The mean drag coefficient of the upstream cylinder is larger than that of the downstream cylinder for the same combination of G/D and L/D. It is also observed that change in the vortex shedding modes leads to a significant increase in the RMS values of drag and lift coefficients.
基金financially supported by the Fundamental Research Funds for the Central Universities(No.FRF-BR-10-037B)the National Natural Science Foundation of China No.51131005
文摘The anodic dissolution process of a crack tip at 2024-T351 aluminium alloy （AA2024-T351） was determined by means of scanning Kelvin probe （SKP）. Wedge-open loading （WOL） specimens were immersed in a 3.5wt% NaCl solution. After various durations of immersion, the Volta potential distributions around the crack were measured by SKP and the surface morphologies were observed by scanning electron microscopy （SEM）. It is found that there is a nonuniform distribution of Volta potential around the crack. Before immersion, the Volta potential at crack tip is more negative than that in other regions. However, after immersion, a converse result occurs with the most positive Volta potential measured at the crack tip. SEM observations demonstrate that the noticeable positive shift of Volta potential results fi：om the formation of corrosion products which deposit around the crack tip. Energy-dispersive spectrometry （EDS） analysis shows that the corrosion products are mainly A1 oxide and Cu-rich particles. These observations implicate that the applied stress contributes to the preferential anodic dissolution of the crack tip and the redistribution of Cu.
