As a common clinical syndrome,voiding dysfunction is complicated in etiology,involved in a variety of diseases and associated with multi-disciplines of medicine.Either medication or surgery has not obtained the favora...As a common clinical syndrome,voiding dysfunction is complicated in etiology,involved in a variety of diseases and associated with multi-disciplines of medicine.Either medication or surgery has not obtained the favorable effect on it.Integrated the theories of traditional Chinese medicine and Western medicine and based on the pathogenesis of the disease,the acupoint specificity and neuromodulatory effects,Professor Wei-bin GAO suggested"selecting the acupoints along the affected areas"The acupoints located near to the lumbar,sacral and abdominal regions are dominated and stimulated with electroacupuncture at different electric waves.In treatment,electric stimulation with disperse and dense waves was adopted.The bone conduction theory of dense-wave electric field was proposed.The same neuromodulation is presented in different diseases such as neurogenic bladder,pediatric enuresis,senile nocturia,benign prostatic hyerplasia,and postpartum of postoperative urination disorders.Hence,the same therapeutic method is adoptable to different diseases with the basic acupoint composition modified.展开更多
AIM To evaluate the risk profile of sulfur hexafluoride in voiding urosonography(VUS)based on a large cohort of children.METHODS Since 2011 sulfur hexafluoride(SH,SonoV ue?,Bracco,Italy)is the only ultrasound contrast...AIM To evaluate the risk profile of sulfur hexafluoride in voiding urosonography(VUS)based on a large cohort of children.METHODS Since 2011 sulfur hexafluoride(SH,SonoV ue?,Bracco,Italy)is the only ultrasound contrast available in the European Union and its use in children has not been approved.Within a 4-year-period,531 children with suspected or proven vesicoureteral reflux(f/m=478/53;mean age 4.9 years;1 mo-25.2 years)following parental informed consent underwent VUS with administration of 2.6±1.2 mL SH in a two-center study.A standardizedtelephone survey on adverse events was conducted three days later.RESULTS No acute adverse reactions were observed.The survey revealed subacute,mostly self-limited adverse events in 4.1%(22/531).The majority of observed adverse events(17/22)was not suspected to be caused by an allergic reaction:Five were related to catheter placement,three to reactivated urinary tract infections,five were associated with perineal disinfection before voiding urosonography or perineal dermatitis and four with a common cold.In five patients(0.9%)hints to a potential allergic cause were noted:Perineal urticaria was reported in three interviews and isolated,mild fever in two.These were minor self-limited adverse events with a subacute onset and no hospital admittance was necessary.Ninety-six point two percent of the parents would prefer future VUS examinations with use of SH.CONCLUSION No severe adverse events were observed and indications of self-limited minor allergic reactions related to intravesical administration of SH were reported in less than 1%.展开更多
Background:Vesicoureteral reflux is the most common urinary congenital anomaly in children.Given the risk associated with radiation exposure there has been an increasing need for radiation-free method in the diagnosis...Background:Vesicoureteral reflux is the most common urinary congenital anomaly in children.Given the risk associated with radiation exposure there has been an increasing need for radiation-free method in the diagnosis and follow-up of the vesicoureteral reflux.The aim of our study is to compare conventional urosonography without contrast enhancement and x-ray voiding cystourethrography.Patients and Methods:Children with recurrent urinary tract infection with suspected vesicoureteral reflux were included to the study.Vesicoureteral reflux is demonstrated and graded by x-ray voiding cystourethrography.DMSA is used for the evaluation of renal scar.Conventional sonographic procedure was performed in all patients.Ureterovesical junction insertion angle was evaluated.The diameter and length of the ureterovesical junction were also measured.Results:268 children enrolled to the study.Vesicoureteral reflux was demonstrated in 62 children by x-ray voiding cystourethrography.Ureterovesical junction insertion angle measurement had a statistically significant relation for right and left vesicoureteral reflux presence(right:r:.646,p:.01 and left:r:.446,p:.01).Diagnosis sensitivity of vesicoureteral reflux with conventional ultrasonography is 95.10%and specificity is 81%(Youden’s index 76.1%)for the cutoff value of the ureterovesical junction insertion angle is 28.6 degrees.Positive predictive value is 87.2%,negative predictive value is 94.73%and diagnostic accuracy is 86.29%with conventional ultrasonography.Conclusions:Measurement of ureterovesical junction insertion angle,length and diameter by conventional urosonography is an easy accessible and cheap technique with high sensitivity and specificity for the diagnosis and followup of the vesicoureteral reflux without exposure to ionizing radiation.展开更多
BACKGROUND Vaginal abscess is a treatable disease and should be considered in female patients with voiding difficulties and perineal tenderness. There are no reported cases of vaginal abscess causing voiding dysfuncti...BACKGROUND Vaginal abscess is a treatable disease and should be considered in female patients with voiding difficulties and perineal tenderness. There are no reported cases of vaginal abscess causing voiding dysfunction in the absence of a previous surgery. Early diagnosis and drainage of vaginal abscesses may lead to excellent outcomes.CASE SUMMARY We presented a case of vaginal abscess that caused voiding dysfunction without surgery history. A 64-yearold woman had a past history of type 2 diabetes mellitus. She came to our clinic following urinary difficulty with perineal tenderness. Bladder ultrasonography revealed a pelvic cystic lesion with a mass effect on the bladder. The presence of a vaginal abscess was suspected following pelvic examination and transvaginal ultrasound.After transvaginal drainage of the vaginal abscess and a full course of antibiotic treatment, she recovered well without any urination symptoms. CONCLUSION Voiding dysfunction caused by vaginal abscess is rare but should be considered in female patients with perineal tenderness.展开更多
Purpose: This study intended to assess the feasibility of an individualized voiding program in Japan aimed at improving the sense of micturition control in older people with functional urinary incontinence. Method: Fo...Purpose: This study intended to assess the feasibility of an individualized voiding program in Japan aimed at improving the sense of micturition control in older people with functional urinary incontinence. Method: Following the interview guide, FGIs were conducted in two groups (4 - 6 participants) consisting of nurses and care workers with more than 5 years of experience as practitioners of urination care. Data were analyzed using a qualitative descriptive approach. Results: We determined that the program purpose is to “enable caregivers to work as a well-coordinated team to humanely facilitate excretion independence in older people, which is essential for living with dignity”, as this confirmed the importance of maintaining the sense of micturition control in older people for their well-being. In the program outline, we extracted the following five categories: 1) setting selection criteria for recipients considering the status of micturition induction, 2) careful collection of information and assessment of lower urinary tract symptoms in older people in case of environmental changes, 3) examination of methods used for assessing lower urinary tract symptoms according to the facility environment, 4) confirmation of the recipient’s micturition habits and request for assistance, and 5) conducting necessary examination for setting the intervention period and evaluation period according to the target condition. The feedback on the program guide was summarized in the statement—specific successful cases help frame and implement the micturition induction plan. Conclusion: We confirmed the feasibility of the micturition induction plan for improving the sense of control in older people with functional urinary incontinence. Upon evaluating the program guide, we deemed that referring to specific successful cases helps frame and implement the micturition induction plan. It is extremely important to verify the effectiveness of the program going forward.展开更多
Objective: Evaluation of Botulinum Toxin-A (BTX-A) as an alternative treatment option in patients whom previous treatments were failed. Methods: Between March 2005 and September 2006, a total 19 patients;16 patients w...Objective: Evaluation of Botulinum Toxin-A (BTX-A) as an alternative treatment option in patients whom previous treatments were failed. Methods: Between March 2005 and September 2006, a total 19 patients;16 patients with overactive bladder (5 neurologic, 11 idiopathic), 2 with nocturnal enuresis, 1 with interstitial cystitis, intravesical BTX-A injection was applied. Except one patient, 18 patients with a median age 46 (20 - 80) were registered to the study. Patients were examined at postoperative 3 weeks and 6 months with ICIQ-SF (International Consultation on Incontinence Questionnaire-Short Form) and satisfaction forms used in our clinic. Results: The median follow-up time was 16 months (6 - 18). When evaluated according to diagnosis, symptoms were improved 100% in neurologic overactive bladder (5/5), 80% in idiopathic overactivity (8/10), 50% in nocturnal enuresis (1/2). In one patient with interstitial cystitis there was no improvement. Median efficiency time of BTX-A treatment was 6 months (1 - 17). At 3 weeks and 6 months after the treatment, ICIQ-SF score was decreased to 3.6 and 7.5 respectively from preoperative level of 18.7. Quality of life scores at preoperative, 3 week and 6 months were 9.7, 2.7 and 4.3 respectively. Except 3 patients with overactive neurologic bladder because of spinal cord injury, symptoms of patients with pollacuria and nocturia decreased at 3. week. Even if these rates increased at 6 months they still were significantly less than preoperative status. The spinal cord injured 3 patients had clean intermittent catheterization per 1 hour and had urinary incontinence between the catheterizations preoperatively, however at 3 weeks and 6 months the intervals of catheterisations was 4 hours and 3 hours respectively and also the urinary incontinance between the catheterisations improved. At patient satisfactions, 78% of patients declared that they were pleased and underwent the procedure again and will recommend it to their relatives with similar problems. One patient had a complication as tansient weakness on her legs. Conclusion: BTX-A injections provide an alternative treatment before surgery at overactive bladder especially for those who doesn’t response to medical treatment or cannot use antimuscarinics because of their side effects. Further studies with a greater number of patients are needed for determining the effectiveness of BTX-A on patients with voiding dysfunctions.展开更多
The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its uti...The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its utilization as well as issues connected to its implementation into the reactor core.展开更多
Kirkendall voids(KVs)at the Cu/Sn interface are a typical failure in integrated circuits,leading to solder joint cracking and electrical disconnection.Although the formation of KVs has been attributed to the differenc...Kirkendall voids(KVs)at the Cu/Sn interface are a typical failure in integrated circuits,leading to solder joint cracking and electrical disconnection.Although the formation of KVs has been attributed to the difference in atomic diffusion rates at the Cu/Sn interface,the role of Cu intrinsic"quality"parameters(crystal defects)in this process remains unclear.This work systematically investigated the effects of Cu crystal defects on KVs:Cu substrates with different lattice defects and grain boundaries were prepared using proprietary electrodeposition additives,and the number of defects was quantitatively characterized by micro-strain,geometric dislocation density,and geometric phase analysis.The thermal aging experiments further showed that the formation of intermetallic compounds and KVs was related to crystal defect energy.When the grain boundary energy was higher than the lattice energy,the additional driving force resulted in short-circuit diffusion,causing local Cu depletion and voids.The lowcrystal-defect samples maintained the local Cu/Sn interdiffusion equilibrium,resulting in fewer voids after 1000 h.This study emphasizes that regulating the crystal defects can reduce KVs and provides a new insight for improving the integrated solder joint's reliability.展开更多
A ground girder is laid on the preprocessed subgrade by gravity compaction and integrally uniformly supported by subgrade in maglev transit.The settlement of the maglev subgrade inevitably affects the vibration state ...A ground girder is laid on the preprocessed subgrade by gravity compaction and integrally uniformly supported by subgrade in maglev transit.The settlement of the maglev subgrade inevitably affects the vibration state of the medium and low speed maglev coupled system by the additional deformation of the maglev track.This study investigated the dynamic properties of the coupled vibration system affected by the subgrade settlement.First,a theoretical coupled vibration model of a maglev train-track-ground girder system with uneven subgrade settlement was proposed and verified.Then,the effect mechanism of the coupled system caused by the uneven subgrade settlement was explored.Finally,settlement types and subgrade support voiding were examined.The analysis showed that the uneven subgrade settlement considerably increased the dynamic responses of the levitation control system and maglev vehicle while having a minor influence on those of the track-ground girder.The influence of a single ground girder settling was the strongest,and adjacent sides’settling of two ground girders was the weakest for the vibration of a maglev train.An extremely large uneven settlement exceeding 6 mm led to active levitation control system instability.The subgrade support voiding enlarged the vehicle-induced vibration of the track ground girder.展开更多
Dear Editor,Primary bladder neck obstruction(PBNO)affects approximately 28%–54%of men[1].Its etiology remains unclear.Symptoms of PBNO present as voiding(e.g.,decreased force of stream,hesitancy,intermittent stream,a...Dear Editor,Primary bladder neck obstruction(PBNO)affects approximately 28%–54%of men[1].Its etiology remains unclear.Symptoms of PBNO present as voiding(e.g.,decreased force of stream,hesitancy,intermittent stream,and incomplete emptying),storage(e.g.,frequency,urgency,urge incontinence,and nocturia),or a combination of both[2].Untreated PBNO can lead to bladder dysfunction,bladder diverticula,hydronephrosis,and impaired renal function[3].展开更多
Background Parkinson＇s disease （PD） is an extrapyramidal neurological disorder.Urinary symptoms are frequently present in patients affected by PD.Symptoms such as urgency,frequency,nocturia,and urge incontinence si...Background Parkinson＇s disease （PD） is an extrapyramidal neurological disorder.Urinary symptoms are frequently present in patients affected by PD.Symptoms such as urgency,frequency,nocturia,and urge incontinence significantly impact the patient＇s quality of life.We attempted to investigate the urodynamic changes and treatment of male PD patients with voiding dysfunction by means of a review.Methods Comprehensive urodynamic examinations were performed in 141 male patients with PD associated with voiding dysfunction.Appropriate treatments were given to subgroups that were divided based on test results,and the changes in urodynamic parameters as well as the treatment efficacy were observed.Results Detrusor hyperreflexia without bladder outlet obstruction （BOO） was observed in 35 patients,who exhibited significant improvements in the international prostate symptom score （IPSS）,maximum flow rate （Qmax）,bladder volume at the first desire to void,post-void residual （PVR）,and bladder compliance.Detrusor hyperreflexia associated with BOO was observed in 59 patients.The patients exhibited significant improvements in IPSS,Qmax,PVR,and bladder compliance.Detrusor dysfunction without BOO was observed in 19 patients,for whom the IPSS and the bladder volume at the first desire to void were improved after treatment.Detrusor dysfunction with BOO was found in 28 patients,with no significant improvement in the urodynamic parameters after the treatment.Conclusions Urodynamic examination is recommended for male Parkinson＇s disease patients with voiding dysfunction.Early and effective treatment can improve the bladder function and quality of life of these patients.展开更多
Background： Work in voiding （WIV） of the bladder may be used to evaluate bladder status throughout urination rather than at a single time point. Few studies, however, have assessed WIV owing to the complexity of it...Background： Work in voiding （WIV） of the bladder may be used to evaluate bladder status throughout urination rather than at a single time point. Few studies, however, have assessed WIV owing to the complexity of its calculations. We have developed a method of calculating work capacity of the bladder while voiding and analyzed the associations of bladder work parameters with bladder contractile function and bladder outlet obstruction （BOO）. Methods： The study retrospectively evaluated 160 men and 23 women, aged 〉40 years and with a detrusor pressure at maximal flow rate （PdetQmax） of ≥40 cmH2O in men, who underwent urodynamic testing. The bladder power integration method was used to calculate WIV; WIV per second （WIV/t） and WIV per liter of urine voided （WIV/v） were also calculated. In men, the relationships between these work capacity parameters and PdetQmax and Abrams-Griffiths （AG） number were determined using linear-by-linear association tests, and relationships between work capacity parameters and BOO grade were investigated using Spearman＇s association test. Results： The mean WIV was 1.15 ± 0.78 J and 1.30 ± 0.88 J, mean WIV/t was 22.95 ± 14,45 mW and 23.78 ± 17.02 mW, and mean WIV/v was 5.59 ± 2.32 J/L and 2.83 ± 1.87 J/L in men and women, respectively. In men, WIV/v showed significant positive associations with PdetQmax （r = 0.845, P = 0.000）, AG number （r = 0.814, P = 0.000）, and Schafer class （r = 0.726, P = 0.000）. Conversely, WIV and WIV/t showed no associations with PdetQmax or AG number. In patients with BOO （Schafer class 〉 II）, WIV/v correlated positively with increasing BOO grade. Conclusions： WIV can be calculated from simple urodynamic parameters using the bladder power integration method. WIV/v may be a marker of BOO grade, and the bladder contractile function can be evaluated by WIV and WIV/t.展开更多
High-entropy alloys(HEAs)exhibit the excellent elevated-temperature performance and irradiation resistance due to the important core effect of serious lattice distortion for impeding dislocation motion,as candidate ma...High-entropy alloys(HEAs)exhibit the excellent elevated-temperature performance and irradiation resistance due to the important core effect of serious lattice distortion for impeding dislocation motion,as candidate materials for nuclear applications.Despite the growth of the nuclear power sector,the effects of high-temperature and high-dose irradiation-induced voids on the mechanical properties of HEA in higher power nuclear reactors remain insufficiently researched,hindering its industrial application.In this study,we establish a consistent parameterization crystal plastic constitutive model for the hardening and creep behaviors of HEA,incorporating the spatial distribution of void size and shape effects,in contrast to traditional creep models that rely on temperature-related fitting parameters of the phenomenological power law equation.The model matches well with experimental data at different temperatures and irradiation doses,demonstrating its robustness.The effects of irradiation dose,temperature,and degree of lattice distortion on irradiation hardening and creep behavior of void-containing HEA are investigated.The results indicate that HEA with high lattice distortion exhibits better creep resistance under higher stress loads.The yield stress of irradiated HEA increases with increasing irradiation dose and temperature.The creep resistance increases with increasing irradiation dose and decreases with increasing irradiation temperature.The increase in irradiation dose causes a specific morphological transformation from spherical to cubic voids.The modeling and results could provide an effective theoretical way for tuning the yield strength and alloy design in advanced HEAs to meet irradiation properties.展开更多
Flip-chip technology is widely used in integrated circuit(IC)packaging.Molded underfill transfer molding is the most common process for these products,as the chip and solder bumps must be protected by the encapsulatin...Flip-chip technology is widely used in integrated circuit(IC)packaging.Molded underfill transfer molding is the most common process for these products,as the chip and solder bumps must be protected by the encapsulating material to ensure good reliability.Flow-front merging usually occurs during the molding process,and air is then trapped under the chip,which can form voids in the molded product.The void under the chip may cause stability and reliability problems.However,the flow process is unobservable during the transfer molding process.The engineer can only check for voids in the molded product after the process is complete.Previous studies have used fluid visualization experiments and developed computational fluid dynamics simulation tools to investigate this issue.However,a critical gap remains in establishing a comprehensive three-dimensional model that integrates two-phase flow,accurate venting settings,and fluid surface tension for molded underfill void evaluation—validated by experimental fluid visualization.This study aims to address this gap in the existing literature.In this study,a fluid visualization experiment was designed to simulate the transfer molding process,allowing for the observation of flow-front merging and void formation behaviors.For comparison,a three-dimensional mold flow analysis was also performed.It was found that the numerical simulation of the trapped air compression process under the chip was more accurate when considering the capillary force.The effect of design factors is evaluated in this paper.The results show that the most important factors for void size are fluid viscosity,the gap height under the chip,transfer time,contact angle between the fluid and the contact surfaces,and transfer pressure.Specifically,a smaller gap height beneath the chip aggravates void formation,while lower viscosity,extended transfer time,reduced contact angle,and increased transfer pressure are effective in minimizing void size.The overall results of this study will be useful for product and process design in selecting appropriate solutions for IC packaging,particularly in the development of void-free molded-underfill flip-chip packages.These findings support the optimization of industrial packaging processes in semiconductor manufacturing by guiding material selection and process parameters,ultimately enhancing package reliability and yield.展开更多
Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt format...Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt formations,insoluble impurities and interlayers detach during salt dissolution and accumulate as sediment at the cavern base,thereby reducing the storage capacity and economic viability of salt cavern gas storage(SCGS).This study investigates sediment formation mechanisms,void distribution,and voidage in the Huai'an low-grade salt mine,introducing a novel self-developed physical simulation device for two butted-well horizontal(TWH)caverns that replicates compressed air injection and brine discharge.Experiments comparing“one injection and one discharge”and“two injections and one discharge”modes revealed that(1)compressed air effectively displaces brine from sediment voids,(2)a 0.5 MPa injection pressure corresponds to a 10.3 MPa operational lower limit in practice,aligning with field data,and(3)sediment voidage is approximately 46%,validated via air-brine interface theory.The“two injections and one discharge”mode outperformed in both discharge volume and rate.Additionally,a mathematical model for brine displacement via compressed air was established.These results provide foundational insights for optimizing compressed air energy storage(CAES)in low-grade salt mines,advancing their role in renewable energy integration.展开更多
Compaction grouting is primarily applied based on empiricism,and it is challenging to quantify its densification effect.To address this issue,five sets of laboratory model tests on ideal compaction grouting were condu...Compaction grouting is primarily applied based on empiricism,and it is challenging to quantify its densification effect.To address this issue,five sets of laboratory model tests on ideal compaction grouting were conducted,with varying pressures from 400 kPa to 800 kPa,to quantitatively evaluate the densification effect in unsaturated soils.The response of surrounding soil during compaction grouting was monitored.The changes in dry density and void ratio induced by compaction grouting were obtained by monitoring volumetric water content to determine compaction efficiency.In addition,a model was developed and validated to predict the effective compaction range.The results show that soil dry density increased rapidly during compaction grouting before being stabilized at a consistent level.As expected,it is positively correlated with grouting pressures(GPs)and negatively correlated with the distance from the injection point.At higher GPs,the difference in densification effect around the injection point after compaction grouting was significant.Interestingly,variations in ultimate dry density and peak earth pressures perpendicular to the injection direction exhibited axisymmetric behavior around the injection point when comparing the dry density and earth pressure results.Furthermore,soil densification resulted in a decrease in suction.However,no significant effect of GP on suction at different soil positions was observed.Moreover,compaction efficiency decreased with increasing distance from the injection point,showing a strong linear relationship.In addition,the model results for the effective compaction range were basically consistent with the extrapolated values from the experimental results.展开更多
Large-grain REBa_(2)Cu_(3)O_(7-δ)(REBCO,RE=rare earth)bulk superconductors offer promising magnetic field trapping capabilities due to their high critical current density,making them ideal for many important applicat...Large-grain REBa_(2)Cu_(3)O_(7-δ)(REBCO,RE=rare earth)bulk superconductors offer promising magnetic field trapping capabilities due to their high critical current density,making them ideal for many important applications such as trapped field magnets.However,for such large-grain superconductor bulks,there are lots of voids and cracks forming during the process of melting preparation,and some of them can be up to hundreds of microns or even millimeters in size.Consequently,these larger size voids/cracks pose a great threat to the strength of the bulks due to the inherent brittleness of superconductor REBCO materials.In order to ensure the operational safety of related superconducting devices with bulk superconductors,it is firstly important to accurately detect these voids/cracks in them.In this paper,we proposed a method for quantitatively evaluating multiple voids/cracks in bulk superconductors through the magnetic field and displacement response signals at superconductor bulk surface.The proposed method utilizes a damage index constructed from the magnetic field signals and displacement responses to identify the number and preliminary location of multiple defects.By dividing the detection area into subdomains and combining the magnetic field signals with displacement responses within each subdomain,a particle swarm algorithm was employed to evaluate the location and size parameters of the defects.In contrast to other evaluation methods using only magnetic field or displacement response signals,the combined evaluation method using both signals can identify the number of cracks effectively.Numerical studies demonstrate that the morphology of voids and cracks reconstructed using the proposed algorithm ideally matches real defects and is applicable to cases where voids and cracks coexist.This study provides a theoretical basis for the quantitative detection of voids/cracks in bulk superconductors.展开更多
This work investigates the dynamic response of a monocrystalline nickel-titanium(NiTi)alloy at the atomic scale.The results deduced from non-equilibrium molecular dynamics modeling demonstrate that no shear deformatio...This work investigates the dynamic response of a monocrystalline nickel-titanium(NiTi)alloy at the atomic scale.The results deduced from non-equilibrium molecular dynamics modeling demonstrate that no shear deformation band(SDB)appears in the sample at an impact velocity of less than 0.75 km/s.As this velocity increases,shear deformations become pronouncedly localized,and the average spacing between SDBs decreases until it stabilizes.Combining shear stress and particle velocity profiles,the survival of SDBs is found to be closely associated with plastic deformation.The dislocations clustering around SDBs predominantly exhibit 100 partial dislocations,whereas 1/2111 full dislocations are dominant in those regions without SDBs.Void nucleation always occurs on SDBs.Subsequently,void growth promotes a change in the SDB distribution characteristic.For the case without SDB,voids are randomly nucleated,and the void growth exhibits a non-uniform manner.Thus,there is an interaction between shear localization and void evolution in the NiTi alloy subjected to intensive loading.This study is expected to provide in-depth insights into the microscopic mechanism of NiTi dynamic damage.展开更多
It has been well recognized that sand particles significantly affect the mechanical properties of reconstituted sandy clays,including the hosted clay and sand particles.However,interrelation between the permeability a...It has been well recognized that sand particles significantly affect the mechanical properties of reconstituted sandy clays,including the hosted clay and sand particles.However,interrelation between the permeability and compressibility of reconstituted sandy clays by considering the structural effects of sand particles is still rarely reported.For this,a series of consolidation-permeability coefficient tests were conducted on reconstituted sandy clays with different sand fractions(ψ_(ss)),initial void ratio of hosted clays(e_(c0))and void ratio at liquid limit of hosted clays(e_(cL)).The roles of ψ_(ss) in both the relationships of permeability coefficient of hosted clay(k_(v-hosted clay))versus effective vertical stress(σ'_(v))and void ratio of hosted clay(e_(c-hosted clay))versus σ'_(v) were analyzed.The results show that the permeability coefficient of reconstituted sandy clays(k_(v))is dominated by hosted clay(k_(v)=k_(v-hosted clay)).Both ψ_(ss) and σ'_(v) affect the k_(v) of sandy clays by changing the e_(c-hosted clay) at any given σ'_(v).Due to the partial contacts and densified clay bridges between the sand particles(i.e.structure effects),the e_(c-hosted clay) in sandy clays is higher than that in clays at the same σ'_(v)v.The k_(v)-e_(c-hosted clay) relationship of sandy clays is independent of σ'_(v) and ψ_(ss)but is a function of e_(cL).The types of hosted clays affect the k_(v) of sandy clays by changing the e_(cL).Based on the relationship between permeability coefficient and void ratio for the reconstituted clays,an empirical method for determining the k_(v) is proposed and validated for sandy clays.The predicted values are almost consistent with the measured values with k_(v-predicted)=k_(v-measured)=0.6-2.5.展开更多
Nickel-based alloys are the primary structural materials in steam generators of high-temperature gas reactors.To understand the irradiation effect of nickel-based alloys,it is necessary to examine dislocation movement...Nickel-based alloys are the primary structural materials in steam generators of high-temperature gas reactors.To understand the irradiation effect of nickel-based alloys,it is necessary to examine dislocation movement and its interaction with irradiation defects at the microscale.Hardening due to voids and Ni_(3)Al precipitates may significantly impact irradiation damage in nickel-based alloys.This paper employs the molecular dynamics method to analyze the interaction between edge dislocations and irradiation defects(void and Ni_(3)Al precipitates)in face-centered cubic nickel.The effects of temperature and defect size on the interaction are also explored.The results show that the interaction process of the edge dislocation and irradiation defects can be divided into four stages:dislocation free slip,dislocation attracted,dislocation pinned,and dislocation unpinned.Interaction modes include the formation of stair-rod dislocations and the climbing of extended dislocation bundles for voids,as well as the generation of stair-rod dislocation and dislocation shear for precipitates.Besides,the interactions of edge dislocations with voids and Ni_(3)Al precipitates are strongly influenced by temperature and defect size.展开更多
基金Supported by Evidence-Based Capacity Building Project of Traditional Chinese Medicine,National Administration of Traditional Chinese Medicine:2019xzzXZJ005。
文摘As a common clinical syndrome,voiding dysfunction is complicated in etiology,involved in a variety of diseases and associated with multi-disciplines of medicine.Either medication or surgery has not obtained the favorable effect on it.Integrated the theories of traditional Chinese medicine and Western medicine and based on the pathogenesis of the disease,the acupoint specificity and neuromodulatory effects,Professor Wei-bin GAO suggested"selecting the acupoints along the affected areas"The acupoints located near to the lumbar,sacral and abdominal regions are dominated and stimulated with electroacupuncture at different electric waves.In treatment,electric stimulation with disperse and dense waves was adopted.The bone conduction theory of dense-wave electric field was proposed.The same neuromodulation is presented in different diseases such as neurogenic bladder,pediatric enuresis,senile nocturia,benign prostatic hyerplasia,and postpartum of postoperative urination disorders.Hence,the same therapeutic method is adoptable to different diseases with the basic acupoint composition modified.
文摘AIM To evaluate the risk profile of sulfur hexafluoride in voiding urosonography(VUS)based on a large cohort of children.METHODS Since 2011 sulfur hexafluoride(SH,SonoV ue?,Bracco,Italy)is the only ultrasound contrast available in the European Union and its use in children has not been approved.Within a 4-year-period,531 children with suspected or proven vesicoureteral reflux(f/m=478/53;mean age 4.9 years;1 mo-25.2 years)following parental informed consent underwent VUS with administration of 2.6±1.2 mL SH in a two-center study.A standardizedtelephone survey on adverse events was conducted three days later.RESULTS No acute adverse reactions were observed.The survey revealed subacute,mostly self-limited adverse events in 4.1%(22/531).The majority of observed adverse events(17/22)was not suspected to be caused by an allergic reaction:Five were related to catheter placement,three to reactivated urinary tract infections,five were associated with perineal disinfection before voiding urosonography or perineal dermatitis and four with a common cold.In five patients(0.9%)hints to a potential allergic cause were noted:Perineal urticaria was reported in three interviews and isolated,mild fever in two.These were minor self-limited adverse events with a subacute onset and no hospital admittance was necessary.Ninety-six point two percent of the parents would prefer future VUS examinations with use of SH.CONCLUSION No severe adverse events were observed and indications of self-limited minor allergic reactions related to intravesical administration of SH were reported in less than 1%.
文摘Background:Vesicoureteral reflux is the most common urinary congenital anomaly in children.Given the risk associated with radiation exposure there has been an increasing need for radiation-free method in the diagnosis and follow-up of the vesicoureteral reflux.The aim of our study is to compare conventional urosonography without contrast enhancement and x-ray voiding cystourethrography.Patients and Methods:Children with recurrent urinary tract infection with suspected vesicoureteral reflux were included to the study.Vesicoureteral reflux is demonstrated and graded by x-ray voiding cystourethrography.DMSA is used for the evaluation of renal scar.Conventional sonographic procedure was performed in all patients.Ureterovesical junction insertion angle was evaluated.The diameter and length of the ureterovesical junction were also measured.Results:268 children enrolled to the study.Vesicoureteral reflux was demonstrated in 62 children by x-ray voiding cystourethrography.Ureterovesical junction insertion angle measurement had a statistically significant relation for right and left vesicoureteral reflux presence(right:r:.646,p:.01 and left:r:.446,p:.01).Diagnosis sensitivity of vesicoureteral reflux with conventional ultrasonography is 95.10%and specificity is 81%(Youden’s index 76.1%)for the cutoff value of the ureterovesical junction insertion angle is 28.6 degrees.Positive predictive value is 87.2%,negative predictive value is 94.73%and diagnostic accuracy is 86.29%with conventional ultrasonography.Conclusions:Measurement of ureterovesical junction insertion angle,length and diameter by conventional urosonography is an easy accessible and cheap technique with high sensitivity and specificity for the diagnosis and followup of the vesicoureteral reflux without exposure to ionizing radiation.
文摘BACKGROUND Vaginal abscess is a treatable disease and should be considered in female patients with voiding difficulties and perineal tenderness. There are no reported cases of vaginal abscess causing voiding dysfunction in the absence of a previous surgery. Early diagnosis and drainage of vaginal abscesses may lead to excellent outcomes.CASE SUMMARY We presented a case of vaginal abscess that caused voiding dysfunction without surgery history. A 64-yearold woman had a past history of type 2 diabetes mellitus. She came to our clinic following urinary difficulty with perineal tenderness. Bladder ultrasonography revealed a pelvic cystic lesion with a mass effect on the bladder. The presence of a vaginal abscess was suspected following pelvic examination and transvaginal ultrasound.After transvaginal drainage of the vaginal abscess and a full course of antibiotic treatment, she recovered well without any urination symptoms. CONCLUSION Voiding dysfunction caused by vaginal abscess is rare but should be considered in female patients with perineal tenderness.
文摘Purpose: This study intended to assess the feasibility of an individualized voiding program in Japan aimed at improving the sense of micturition control in older people with functional urinary incontinence. Method: Following the interview guide, FGIs were conducted in two groups (4 - 6 participants) consisting of nurses and care workers with more than 5 years of experience as practitioners of urination care. Data were analyzed using a qualitative descriptive approach. Results: We determined that the program purpose is to “enable caregivers to work as a well-coordinated team to humanely facilitate excretion independence in older people, which is essential for living with dignity”, as this confirmed the importance of maintaining the sense of micturition control in older people for their well-being. In the program outline, we extracted the following five categories: 1) setting selection criteria for recipients considering the status of micturition induction, 2) careful collection of information and assessment of lower urinary tract symptoms in older people in case of environmental changes, 3) examination of methods used for assessing lower urinary tract symptoms according to the facility environment, 4) confirmation of the recipient’s micturition habits and request for assistance, and 5) conducting necessary examination for setting the intervention period and evaluation period according to the target condition. The feedback on the program guide was summarized in the statement—specific successful cases help frame and implement the micturition induction plan. Conclusion: We confirmed the feasibility of the micturition induction plan for improving the sense of control in older people with functional urinary incontinence. Upon evaluating the program guide, we deemed that referring to specific successful cases helps frame and implement the micturition induction plan. It is extremely important to verify the effectiveness of the program going forward.
文摘Objective: Evaluation of Botulinum Toxin-A (BTX-A) as an alternative treatment option in patients whom previous treatments were failed. Methods: Between March 2005 and September 2006, a total 19 patients;16 patients with overactive bladder (5 neurologic, 11 idiopathic), 2 with nocturnal enuresis, 1 with interstitial cystitis, intravesical BTX-A injection was applied. Except one patient, 18 patients with a median age 46 (20 - 80) were registered to the study. Patients were examined at postoperative 3 weeks and 6 months with ICIQ-SF (International Consultation on Incontinence Questionnaire-Short Form) and satisfaction forms used in our clinic. Results: The median follow-up time was 16 months (6 - 18). When evaluated according to diagnosis, symptoms were improved 100% in neurologic overactive bladder (5/5), 80% in idiopathic overactivity (8/10), 50% in nocturnal enuresis (1/2). In one patient with interstitial cystitis there was no improvement. Median efficiency time of BTX-A treatment was 6 months (1 - 17). At 3 weeks and 6 months after the treatment, ICIQ-SF score was decreased to 3.6 and 7.5 respectively from preoperative level of 18.7. Quality of life scores at preoperative, 3 week and 6 months were 9.7, 2.7 and 4.3 respectively. Except 3 patients with overactive neurologic bladder because of spinal cord injury, symptoms of patients with pollacuria and nocturia decreased at 3. week. Even if these rates increased at 6 months they still were significantly less than preoperative status. The spinal cord injured 3 patients had clean intermittent catheterization per 1 hour and had urinary incontinence between the catheterizations preoperatively, however at 3 weeks and 6 months the intervals of catheterisations was 4 hours and 3 hours respectively and also the urinary incontinance between the catheterisations improved. At patient satisfactions, 78% of patients declared that they were pleased and underwent the procedure again and will recommend it to their relatives with similar problems. One patient had a complication as tansient weakness on her legs. Conclusion: BTX-A injections provide an alternative treatment before surgery at overactive bladder especially for those who doesn’t response to medical treatment or cannot use antimuscarinics because of their side effects. Further studies with a greater number of patients are needed for determining the effectiveness of BTX-A on patients with voiding dysfunctions.
文摘The paper describes the instrumentation for studying temperature and void reactivity effects that were developed at VR-I zero power reactor. Further are described its operational parameters, fields and ways of its utilization as well as issues connected to its implementation into the reactor core.
基金financially supported by the National Natural Science Foundation of China(Nos.62274172 and 62304143)High-level Talent Innovation and Entrepreneurship Plan of Shenzhen Key Technology Research and Development Team Funding Application(No.JSGGKQTD20221101115650008)+2 种基金Shenzhen-Hong Kong-Macao Science and Technology Plan Project(Category C)(No.SGDX20220530111004028)Macao Science and Technology Development Fund(FDCT)for funding(No.0013/2024/RIB1)the Multi-Year Research Grant(MYRG)from University of Macao(Nos.MYRG-GRG2023-00140-IAPME-UMDF and MYRG-GRG2024-00206-IAPME)
文摘Kirkendall voids(KVs)at the Cu/Sn interface are a typical failure in integrated circuits,leading to solder joint cracking and electrical disconnection.Although the formation of KVs has been attributed to the difference in atomic diffusion rates at the Cu/Sn interface,the role of Cu intrinsic"quality"parameters(crystal defects)in this process remains unclear.This work systematically investigated the effects of Cu crystal defects on KVs:Cu substrates with different lattice defects and grain boundaries were prepared using proprietary electrodeposition additives,and the number of defects was quantitatively characterized by micro-strain,geometric dislocation density,and geometric phase analysis.The thermal aging experiments further showed that the formation of intermetallic compounds and KVs was related to crystal defect energy.When the grain boundary energy was higher than the lattice energy,the additional driving force resulted in short-circuit diffusion,causing local Cu depletion and voids.The lowcrystal-defect samples maintained the local Cu/Sn interdiffusion equilibrium,resulting in fewer voids after 1000 h.This study emphasizes that regulating the crystal defects can reduce KVs and provides a new insight for improving the integrated solder joint's reliability.
基金National Natural Science Foundation of China under Grant Nos.52478467and 52108417Guangdong Basic and Applied Basic Research Foundation under Grant No.2024A1515012569the Natural Science Basic Research Program of Shaanxi under Grant No.2021JQ-101。
文摘A ground girder is laid on the preprocessed subgrade by gravity compaction and integrally uniformly supported by subgrade in maglev transit.The settlement of the maglev subgrade inevitably affects the vibration state of the medium and low speed maglev coupled system by the additional deformation of the maglev track.This study investigated the dynamic properties of the coupled vibration system affected by the subgrade settlement.First,a theoretical coupled vibration model of a maglev train-track-ground girder system with uneven subgrade settlement was proposed and verified.Then,the effect mechanism of the coupled system caused by the uneven subgrade settlement was explored.Finally,settlement types and subgrade support voiding were examined.The analysis showed that the uneven subgrade settlement considerably increased the dynamic responses of the levitation control system and maglev vehicle while having a minor influence on those of the track-ground girder.The influence of a single ground girder settling was the strongest,and adjacent sides’settling of two ground girders was the weakest for the vibration of a maglev train.An extremely large uneven settlement exceeding 6 mm led to active levitation control system instability.The subgrade support voiding enlarged the vehicle-induced vibration of the track ground girder.
文摘Dear Editor,Primary bladder neck obstruction(PBNO)affects approximately 28%–54%of men[1].Its etiology remains unclear.Symptoms of PBNO present as voiding(e.g.,decreased force of stream,hesitancy,intermittent stream,and incomplete emptying),storage(e.g.,frequency,urgency,urge incontinence,and nocturia),or a combination of both[2].Untreated PBNO can lead to bladder dysfunction,bladder diverticula,hydronephrosis,and impaired renal function[3].
文摘Background Parkinson＇s disease （PD） is an extrapyramidal neurological disorder.Urinary symptoms are frequently present in patients affected by PD.Symptoms such as urgency,frequency,nocturia,and urge incontinence significantly impact the patient＇s quality of life.We attempted to investigate the urodynamic changes and treatment of male PD patients with voiding dysfunction by means of a review.Methods Comprehensive urodynamic examinations were performed in 141 male patients with PD associated with voiding dysfunction.Appropriate treatments were given to subgroups that were divided based on test results,and the changes in urodynamic parameters as well as the treatment efficacy were observed.Results Detrusor hyperreflexia without bladder outlet obstruction （BOO） was observed in 35 patients,who exhibited significant improvements in the international prostate symptom score （IPSS）,maximum flow rate （Qmax）,bladder volume at the first desire to void,post-void residual （PVR）,and bladder compliance.Detrusor hyperreflexia associated with BOO was observed in 59 patients.The patients exhibited significant improvements in IPSS,Qmax,PVR,and bladder compliance.Detrusor dysfunction without BOO was observed in 19 patients,for whom the IPSS and the bladder volume at the first desire to void were improved after treatment.Detrusor dysfunction with BOO was found in 28 patients,with no significant improvement in the urodynamic parameters after the treatment.Conclusions Urodynamic examination is recommended for male Parkinson＇s disease patients with voiding dysfunction.Early and effective treatment can improve the bladder function and quality of life of these patients.
文摘Background： Work in voiding （WIV） of the bladder may be used to evaluate bladder status throughout urination rather than at a single time point. Few studies, however, have assessed WIV owing to the complexity of its calculations. We have developed a method of calculating work capacity of the bladder while voiding and analyzed the associations of bladder work parameters with bladder contractile function and bladder outlet obstruction （BOO）. Methods： The study retrospectively evaluated 160 men and 23 women, aged 〉40 years and with a detrusor pressure at maximal flow rate （PdetQmax） of ≥40 cmH2O in men, who underwent urodynamic testing. The bladder power integration method was used to calculate WIV; WIV per second （WIV/t） and WIV per liter of urine voided （WIV/v） were also calculated. In men, the relationships between these work capacity parameters and PdetQmax and Abrams-Griffiths （AG） number were determined using linear-by-linear association tests, and relationships between work capacity parameters and BOO grade were investigated using Spearman＇s association test. Results： The mean WIV was 1.15 ± 0.78 J and 1.30 ± 0.88 J, mean WIV/t was 22.95 ± 14,45 mW and 23.78 ± 17.02 mW, and mean WIV/v was 5.59 ± 2.32 J/L and 2.83 ± 1.87 J/L in men and women, respectively. In men, WIV/v showed significant positive associations with PdetQmax （r = 0.845, P = 0.000）, AG number （r = 0.814, P = 0.000）, and Schafer class （r = 0.726, P = 0.000）. Conversely, WIV and WIV/t showed no associations with PdetQmax or AG number. In patients with BOO （Schafer class 〉 II）, WIV/v correlated positively with increasing BOO grade. Conclusions： WIV can be calculated from simple urodynamic parameters using the bladder power integration method. WIV/v may be a marker of BOO grade, and the bladder contractile function can be evaluated by WIV and WIV/t.
基金support from the National Natural Science Foundation of China(Nos.12302083,U2267252,12372069,and 12172123)the China Postdoctoral Science Foundation(Nos.2023M731061 and BX20230109)+1 种基金the Natural Science Foundation of Hunan Province(No.2022JJ20001)the Hunan Provincial Innovation Foundation for Postgraduate(No.CX20230420).
文摘High-entropy alloys(HEAs)exhibit the excellent elevated-temperature performance and irradiation resistance due to the important core effect of serious lattice distortion for impeding dislocation motion,as candidate materials for nuclear applications.Despite the growth of the nuclear power sector,the effects of high-temperature and high-dose irradiation-induced voids on the mechanical properties of HEA in higher power nuclear reactors remain insufficiently researched,hindering its industrial application.In this study,we establish a consistent parameterization crystal plastic constitutive model for the hardening and creep behaviors of HEA,incorporating the spatial distribution of void size and shape effects,in contrast to traditional creep models that rely on temperature-related fitting parameters of the phenomenological power law equation.The model matches well with experimental data at different temperatures and irradiation doses,demonstrating its robustness.The effects of irradiation dose,temperature,and degree of lattice distortion on irradiation hardening and creep behavior of void-containing HEA are investigated.The results indicate that HEA with high lattice distortion exhibits better creep resistance under higher stress loads.The yield stress of irradiated HEA increases with increasing irradiation dose and temperature.The creep resistance increases with increasing irradiation dose and decreases with increasing irradiation temperature.The increase in irradiation dose causes a specific morphological transformation from spherical to cubic voids.The modeling and results could provide an effective theoretical way for tuning the yield strength and alloy design in advanced HEAs to meet irradiation properties.
文摘Flip-chip technology is widely used in integrated circuit(IC)packaging.Molded underfill transfer molding is the most common process for these products,as the chip and solder bumps must be protected by the encapsulating material to ensure good reliability.Flow-front merging usually occurs during the molding process,and air is then trapped under the chip,which can form voids in the molded product.The void under the chip may cause stability and reliability problems.However,the flow process is unobservable during the transfer molding process.The engineer can only check for voids in the molded product after the process is complete.Previous studies have used fluid visualization experiments and developed computational fluid dynamics simulation tools to investigate this issue.However,a critical gap remains in establishing a comprehensive three-dimensional model that integrates two-phase flow,accurate venting settings,and fluid surface tension for molded underfill void evaluation—validated by experimental fluid visualization.This study aims to address this gap in the existing literature.In this study,a fluid visualization experiment was designed to simulate the transfer molding process,allowing for the observation of flow-front merging and void formation behaviors.For comparison,a three-dimensional mold flow analysis was also performed.It was found that the numerical simulation of the trapped air compression process under the chip was more accurate when considering the capillary force.The effect of design factors is evaluated in this paper.The results show that the most important factors for void size are fluid viscosity,the gap height under the chip,transfer time,contact angle between the fluid and the contact surfaces,and transfer pressure.Specifically,a smaller gap height beneath the chip aggravates void formation,while lower viscosity,extended transfer time,reduced contact angle,and increased transfer pressure are effective in minimizing void size.The overall results of this study will be useful for product and process design in selecting appropriate solutions for IC packaging,particularly in the development of void-free molded-underfill flip-chip packages.These findings support the optimization of industrial packaging processes in semiconductor manufacturing by guiding material selection and process parameters,ultimately enhancing package reliability and yield.
基金financial support from the National Key Research and Development Program of China(No.2024YFB4007100)the Basic ForwardLooking Project of the Sinopec Science and Technology Department,“Research on the Long-Term Sealing Mechanism of Multi-layer Salt Cavern Hydrogen Storage”(No.P24197-4)。
文摘Renewable energy storage technologies are critical for transitioning to sustainable energy systems,with salt caverns playing a significant role in large-scale solutions.In water-soluble mining of low-grade salt formations,insoluble impurities and interlayers detach during salt dissolution and accumulate as sediment at the cavern base,thereby reducing the storage capacity and economic viability of salt cavern gas storage(SCGS).This study investigates sediment formation mechanisms,void distribution,and voidage in the Huai'an low-grade salt mine,introducing a novel self-developed physical simulation device for two butted-well horizontal(TWH)caverns that replicates compressed air injection and brine discharge.Experiments comparing“one injection and one discharge”and“two injections and one discharge”modes revealed that(1)compressed air effectively displaces brine from sediment voids,(2)a 0.5 MPa injection pressure corresponds to a 10.3 MPa operational lower limit in practice,aligning with field data,and(3)sediment voidage is approximately 46%,validated via air-brine interface theory.The“two injections and one discharge”mode outperformed in both discharge volume and rate.Additionally,a mathematical model for brine displacement via compressed air was established.These results provide foundational insights for optimizing compressed air energy storage(CAES)in low-grade salt mines,advancing their role in renewable energy integration.
基金the National Natural Science Foundation of China(Grant Nos.42172298,42002289)the Shanghai Geological Star Program for their financial support.
文摘Compaction grouting is primarily applied based on empiricism,and it is challenging to quantify its densification effect.To address this issue,five sets of laboratory model tests on ideal compaction grouting were conducted,with varying pressures from 400 kPa to 800 kPa,to quantitatively evaluate the densification effect in unsaturated soils.The response of surrounding soil during compaction grouting was monitored.The changes in dry density and void ratio induced by compaction grouting were obtained by monitoring volumetric water content to determine compaction efficiency.In addition,a model was developed and validated to predict the effective compaction range.The results show that soil dry density increased rapidly during compaction grouting before being stabilized at a consistent level.As expected,it is positively correlated with grouting pressures(GPs)and negatively correlated with the distance from the injection point.At higher GPs,the difference in densification effect around the injection point after compaction grouting was significant.Interestingly,variations in ultimate dry density and peak earth pressures perpendicular to the injection direction exhibited axisymmetric behavior around the injection point when comparing the dry density and earth pressure results.Furthermore,soil densification resulted in a decrease in suction.However,no significant effect of GP on suction at different soil positions was observed.Moreover,compaction efficiency decreased with increasing distance from the injection point,showing a strong linear relationship.In addition,the model results for the effective compaction range were basically consistent with the extrapolated values from the experimental results.
基金supported by the National Natural Science Foundation of China(Grant Nos.12232005 and 12072101).
文摘Large-grain REBa_(2)Cu_(3)O_(7-δ)(REBCO,RE=rare earth)bulk superconductors offer promising magnetic field trapping capabilities due to their high critical current density,making them ideal for many important applications such as trapped field magnets.However,for such large-grain superconductor bulks,there are lots of voids and cracks forming during the process of melting preparation,and some of them can be up to hundreds of microns or even millimeters in size.Consequently,these larger size voids/cracks pose a great threat to the strength of the bulks due to the inherent brittleness of superconductor REBCO materials.In order to ensure the operational safety of related superconducting devices with bulk superconductors,it is firstly important to accurately detect these voids/cracks in them.In this paper,we proposed a method for quantitatively evaluating multiple voids/cracks in bulk superconductors through the magnetic field and displacement response signals at superconductor bulk surface.The proposed method utilizes a damage index constructed from the magnetic field signals and displacement responses to identify the number and preliminary location of multiple defects.By dividing the detection area into subdomains and combining the magnetic field signals with displacement responses within each subdomain,a particle swarm algorithm was employed to evaluate the location and size parameters of the defects.In contrast to other evaluation methods using only magnetic field or displacement response signals,the combined evaluation method using both signals can identify the number of cracks effectively.Numerical studies demonstrate that the morphology of voids and cracks reconstructed using the proposed algorithm ideally matches real defects and is applicable to cases where voids and cracks coexist.This study provides a theoretical basis for the quantitative detection of voids/cracks in bulk superconductors.
基金supported by the National Natural Science Foundation of China(Grant No.12372367)the Special Foundation of the Institute of Fluid Physics of China Academy of Engineering Physics(Grant No.2022-YCHT-0641).
文摘This work investigates the dynamic response of a monocrystalline nickel-titanium(NiTi)alloy at the atomic scale.The results deduced from non-equilibrium molecular dynamics modeling demonstrate that no shear deformation band(SDB)appears in the sample at an impact velocity of less than 0.75 km/s.As this velocity increases,shear deformations become pronouncedly localized,and the average spacing between SDBs decreases until it stabilizes.Combining shear stress and particle velocity profiles,the survival of SDBs is found to be closely associated with plastic deformation.The dislocations clustering around SDBs predominantly exhibit 100 partial dislocations,whereas 1/2111 full dislocations are dominant in those regions without SDBs.Void nucleation always occurs on SDBs.Subsequently,void growth promotes a change in the SDB distribution characteristic.For the case without SDB,voids are randomly nucleated,and the void growth exhibits a non-uniform manner.Thus,there is an interaction between shear localization and void evolution in the NiTi alloy subjected to intensive loading.This study is expected to provide in-depth insights into the microscopic mechanism of NiTi dynamic damage.
基金supported by the National Natural Science Foundation of China (Grant Nos.52278334 and 4197724)Fundamental Research Funds for the Central Universities (Grant No.2242024k30066).
文摘It has been well recognized that sand particles significantly affect the mechanical properties of reconstituted sandy clays,including the hosted clay and sand particles.However,interrelation between the permeability and compressibility of reconstituted sandy clays by considering the structural effects of sand particles is still rarely reported.For this,a series of consolidation-permeability coefficient tests were conducted on reconstituted sandy clays with different sand fractions(ψ_(ss)),initial void ratio of hosted clays(e_(c0))and void ratio at liquid limit of hosted clays(e_(cL)).The roles of ψ_(ss) in both the relationships of permeability coefficient of hosted clay(k_(v-hosted clay))versus effective vertical stress(σ'_(v))and void ratio of hosted clay(e_(c-hosted clay))versus σ'_(v) were analyzed.The results show that the permeability coefficient of reconstituted sandy clays(k_(v))is dominated by hosted clay(k_(v)=k_(v-hosted clay)).Both ψ_(ss) and σ'_(v) affect the k_(v) of sandy clays by changing the e_(c-hosted clay) at any given σ'_(v).Due to the partial contacts and densified clay bridges between the sand particles(i.e.structure effects),the e_(c-hosted clay) in sandy clays is higher than that in clays at the same σ'_(v)v.The k_(v)-e_(c-hosted clay) relationship of sandy clays is independent of σ'_(v) and ψ_(ss)but is a function of e_(cL).The types of hosted clays affect the k_(v) of sandy clays by changing the e_(cL).Based on the relationship between permeability coefficient and void ratio for the reconstituted clays,an empirical method for determining the k_(v) is proposed and validated for sandy clays.The predicted values are almost consistent with the measured values with k_(v-predicted)=k_(v-measured)=0.6-2.5.
基金supported by the Ministry of Industry and Information Technology of China(grant number TC220A04W-7,203)CNNC Youth Elite Scientific Research Project,the National Key R&D Plan of China(grant number 2020YFB1901600)the National Science Technology Major Project of China(grant numbers 2017ZX06902012 and 2017ZX06901024).
文摘Nickel-based alloys are the primary structural materials in steam generators of high-temperature gas reactors.To understand the irradiation effect of nickel-based alloys,it is necessary to examine dislocation movement and its interaction with irradiation defects at the microscale.Hardening due to voids and Ni_(3)Al precipitates may significantly impact irradiation damage in nickel-based alloys.This paper employs the molecular dynamics method to analyze the interaction between edge dislocations and irradiation defects(void and Ni_(3)Al precipitates)in face-centered cubic nickel.The effects of temperature and defect size on the interaction are also explored.The results show that the interaction process of the edge dislocation and irradiation defects can be divided into four stages:dislocation free slip,dislocation attracted,dislocation pinned,and dislocation unpinned.Interaction modes include the formation of stair-rod dislocations and the climbing of extended dislocation bundles for voids,as well as the generation of stair-rod dislocation and dislocation shear for precipitates.Besides,the interactions of edge dislocations with voids and Ni_(3)Al precipitates are strongly influenced by temperature and defect size.
