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Short-term effects of transcranial direct current stimulation on pain sensitivity, emotional and cognitive processes in non-suicidal self-injury: a randomised controlled trial
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作者 Chang Lei Diyang Qu +4 位作者 Dennis Chong Yangyang Yi Weijian Wu Yiheng Tu Runsen Chen 《General Psychiatry》 2025年第3期176-185,共10页
Background Pain sensitivity is critical for preventing non-suicidal self-injury(NSSI)behaviours;however,individuals engaging in such behaviours often exhibit decreased pain sensitivity,which may undermine this natural... Background Pain sensitivity is critical for preventing non-suicidal self-injury(NSSI)behaviours;however,individuals engaging in such behaviours often exhibit decreased pain sensitivity,which may undermine this natural safeguard.The dorsolateral prefrontal cortex(DLPFC)is a key region involved in pain regulation,and recent approaches using transcranial direct current stimulation(tDCS)to target the DLPFC have shown potential for modulating pain processing and restoring normal pain perception for individuals engaging in NSSI behaviours.Aims This study aimed to explore the immediate and short-term effects of a single session of tDCS on pain sensitivity in individuals with NSSI,as well as its secondary effects on mood and NSSI-related factors.Methods In this randomised,double-blind,parallel,sham-controlled clinical trial,participants with a history of NSSI were randomly assigned to receive either active or sham tDCS.The intervention consisted of a single 20 min tDCS session targeting the left DLPFC.The primary outcome was pain sensitivity,measured by the pressure pain threshold(PPT)and heat pain score(HPS).Secondary and additional outcomes included NSSI urges,NSSI resistance,self-efficacy in resisting NSSI,mood-related variables and exploratory cognitive-affective processes such as rumination,self-criticism and self-perceived pain sensitivity,assessed at baseline,immediately post-intervention,and at 24 hours,1 week and 2 weeks follow-ups.Results For the primary outcomes,no significant differences between groups were observed for pain sensitivity(PPT,padj=0.812;HPS,padj=0.608).However,an exploratory sensitivity analysis treating each trial as an individual observation revealed a significant effect on HPS(padj=0.036).For the secondary and additional outcomes,although there were initial improvements in joyful feelings and reductions in negative affect at 2 weeks post-intervention,these effects did not remain significant after multiple comparison corrections.Notably,reductions in rumination were statistically significant at both 1-week and 2-week follow-ups(1 week,p_(adj)=0.040;2 weeks,p_(adj)=0.042).There were no significant effects on NSSI urges,NSSI resistance,self-efficacy in resisting NSSI or self-criticism.Conclusions A single session of tDCS over the left DLPFC did not produce significant changes in pain sensitivity in individuals with NSSI.A sensitivity analysis indicated an effect on heat pain sensitivity,possibly reflecting changes in brain activity,warranting confirmation through neuroimaging.These findings suggest that tDCS warrants further investigation for its potential to influence pain-related cognitive-affective processes in individuals with NSSI. 展开更多
关键词 Non Suicidal Self Injury MOOD Dorsolateral Prefrontal Cortex modulating pain processing Transcranial direct current Stimulation Cognitive Processes dorsolateral prefrontal cortex dlpfc transcranial direct current stimulation tdcs
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Calculation of Commutation Failure Overvoltage in High-Voltage Direct Current Transmission Terminal Systems with Grid-Forming Renewable Energy Sources
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作者 Weibing Xu Bo Yao +5 位作者 Xiangjun Quan Xunyou Zhang Ning Zou Shuo Liu Jia Wang Jiansuo Zhang 《Energy Engineering》 2025年第10期4225-4243,共19页
The integration of large-scale new energy and high-capacity DC transmission leads to a reduction in system inertia.Grid-forming renewable energy sources(GF-RES)has a significant improvement effect on system inertia.Co... The integration of large-scale new energy and high-capacity DC transmission leads to a reduction in system inertia.Grid-forming renewable energy sources(GF-RES)has a significant improvement effect on system inertia.Commutation failure faults may cause a short-term reactive power surplus at the sending end and trigger transient overvoltage,threatening the safe and stable operation of the power grid.However,there is a lack of research on the calculation method of transient overvoltage caused by commutation failure in high-voltage DC transmission systems with grid-forming renewable energy sources integration.Based on the existing equivalent model of highvoltage DC transmission systems at the sending end,this paper proposes to construct a model of the high-voltage DC transmission system at the sending end with grid-forming renewable energy sources.The paper first clarifies the mechanism of overvoltage generation,then considers the reactive power droop control characteristics of GF-RES,and derives the transient voltage calculation model of theDC transmission system with GF-RES integration.It also proposes a calculation method for transient overvoltage at the sending-end converter bus with GF-RES integration.Based on the PSCAD/EMTDC simulation platform,this paper builds an experimental simulation model.By constructing three different experimental scenarios,the accuracy and effectiveness of the proposed transient overvoltage calculation method are verified,with a calculation error within 5%.At the same time,this paper quantitatively analyzes the impact of grid strength,new energy proportion,and rated transmission power on transient overvoltage from three different perspectives. 展开更多
关键词 Grid-forming renewable energy commutation failure transient overvoltage high-voltage direct current sending-end direct current system
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Refining mechanism of tin–bismuth alloy solidified structure upon applying direct current attached mold
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作者 Si-yao Liu Ye Zhou +4 位作者 Xin-cheng Miao Qing-he Xiao Rui Guan Xin-gang Ai Sheng-li Li 《Journal of Iron and Steel Research International》 2025年第3期619-628,共10页
Herein,the effect of direct current(DC)attached the mold on refining the microstructure and alleviating the central segregation of a tin–bismuth(Sn–10 wt.%Bi)alloy ingot during the solidification process has been in... Herein,the effect of direct current(DC)attached the mold on refining the microstructure and alleviating the central segregation of a tin–bismuth(Sn–10 wt.%Bi)alloy ingot during the solidification process has been investigated.The experiment used a self-made device,which can achieve the effect of refining the solidified structure and alleviate the segregation of the metal casting.Numerical simulations were performed to calculate the Lorentz force,Joule heating and induced melt vortex flow for the magneto-hydrodynamic case.Our results show that the maximum velocity of the global electro-vortex reached 0.017 m s^(–1).The DC-induced electro-vortex was found to be the primary reason of refining the equiaxed grain and alleviating the segregation of theβ-Sn crystal boundary.The grain refining effect observed in these experiments can be solely attributed to the forced melt flow driven by the Lorentz force.DC field attached the mold can lead to grain refinement and alleviate the segregation of the ingot via a global vortex.The technology can be applied not only to opened molds,but also toward improving the quality in closed molds. 展开更多
关键词 Metal solidification direct current Forced melt flow Grain refinement Segregation alleviation
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Therapeutic efficacy of transcranial direct current stimulation in treating auditory hallucinations in schizophrenia:A meta-analysis
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作者 Shi-Jia Zou Jin-Nan Shi 《World Journal of Psychiatry》 2025年第3期302-310,共9页
BACKGROUND Schizophrenia is a chronic psychiatric condition with complex symptomatology,including debilitating auditory hallucinations.Transcranial direct current stimulation(tDCS)has been explored as an adjunctive tr... BACKGROUND Schizophrenia is a chronic psychiatric condition with complex symptomatology,including debilitating auditory hallucinations.Transcranial direct current stimulation(tDCS)has been explored as an adjunctive treatment to alleviate such symptoms.AIM To evaluate the therapeutic efficacy of tDCS in schizophrenia.METHODS Adhering to PRISMA guidelines,we systematically searched PubMed,Embase,Web of Science,and the Cochrane Library on September 19,2023,for randomized controlled trials examining the efficacy of tDCS in schizophrenia,with no language or time restrictions.We included studies that compared tDCS with a control condition and reported clinically relevant outcomes.Data extraction and quality assessments were performed by independent evaluators using the Cochrane Collaboration's risk of bias tool.Statistical heterogeneity was evaluated,and a random-effects model was applied due to moderate heterogeneity(I2=41.3%).RESULTS Nine studies comprising 425 participants(tDCS group:219,control group:206)were included.The meta-analysis demonstrated a significant reduction in auditory hallucination scores following tDCS treatment(weighted mean difference:-2.18,95%confidence interval:-4.0 to-0.29,P<0.01).Sensitivity analysis confirmed the robustness of the results,with no significant influence from individual studies.Additionally,publication bias was not detected,supporting the reliability and generalizability of the findings.These results underscore the efficacy of tDCS as a therapeutic intervention for auditory hallucinations in schizophrenia.CONCLUSION tDCS significantly reduces auditory hallucinations in schizophrenia,suggesting its potential as an effective adjunctive treatment for managing this disabling symptom.The findings highlight the practical significance of tDCS in clinical settings,particularly for patients with treatment-resistant auditory hallucinations. 展开更多
关键词 SCHIZOPHRENIA Transcranial direct current stimulation Auditory hallucinations META-ANALYSIS
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Transcranial direct current stimulation efficacy in trigeminal neuralgia
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作者 Theodoros Fasilis Stylianos Gatzonis +2 位作者 Panayiotis Patrikelis Stefanos Korfias Athanasia Alexoudi 《World Journal of Clinical Cases》 SCIE 2024年第5期1036-1038,共3页
Trigeminal neuralgia is a severe,disabling pain and its deafferentation remains a challenge for health providers.Transcranial direct current stimulation is a non-invasive stimulation technique which finds new utility ... Trigeminal neuralgia is a severe,disabling pain and its deafferentation remains a challenge for health providers.Transcranial direct current stimulation is a non-invasive stimulation technique which finds new utility in managing pain.There-fore,the introduction of alternative,non-invasive,safe,and effective methods should be considered in treating patients with trigeminal neuralgia unresponsive to conventional treatment. 展开更多
关键词 Trigeminal neuralgia Patient-controlled intravenous analgesia NEUROMODULATION Transcranial direct current stimulation
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Effect of transcranial direct current stimulation on supernumerary phantom limb pain in spinal cord injured patient:A case report
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作者 Hyo-Sik Park Jae-Hyung Kim 《World Journal of Clinical Cases》 SCIE 2024年第17期3177-3182,共6页
BACKGROUND Supernumerary phantom limb(SPL)sensation is the experience of additional limbs,either single or a pair of limbs.Unique to traumatic spinal cord injuries,we report effect of transcranial direct current stimu... BACKGROUND Supernumerary phantom limb(SPL)sensation is the experience of additional limbs,either single or a pair of limbs.Unique to traumatic spinal cord injuries,we report effect of transcranial direct current stimulation(tDCS)on SPL pain in a patient with cervical cord injury.CASE SUMMARY The subject was a 57-year-old man who was diagnosed with complete spinal cord injury(C6/C5,motor level;C5/C5,sensory level;AIS-A)approximately three months ago.After a period of 2 wk,we administered anodal tDCS over the motor cortex for 15 minutes at an intensity of 1.5 mA.Following that treatment,the patient experienced a decrease of SPL pain intensity and frequency,which lasted for 1 week after the end of treatment.CONCLUSION Targeting the motor cortex through neuromodulation appears to be a promising option for the management of SPL pain. 展开更多
关键词 Supernumerary phantom limb pain Spinal cord injury transcranial direct current Stimulation NEUROMODULATION Case report
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Research and exploration of direct current power supply and distribution systems for Antarctic research stations
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作者 WANG Lei 《Advances in Polar Science》 CSCD 2024年第2期228-237,共10页
The power supply and distribution systems for Antarctic research stations have special characteristics.In light of a worldwide trend toward a gradual increase in the application of renewable energy,an analysis was per... The power supply and distribution systems for Antarctic research stations have special characteristics.In light of a worldwide trend toward a gradual increase in the application of renewable energy,an analysis was performed to assess the feasibility of achieving a direct current power supply and distribution at Antarctic research stations by comparing the characteristics of direct current and alternating current electricity.Research was also performed on the status quo and future trends in direct current power supply and distribution systems in Antarctica research stations in combination with case studies. 展开更多
关键词 direct current alternating current renewable energy ANTARCTIC research station
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Transcranial Direct Current Stimulation: Effects on Motor and Non-Motor Symptoms of Parkinson’s Disease
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作者 Fayda Protásio Carlos Alberto Bezerra Tomaz +3 位作者 Joaquim Brasil-Neto Pedro Brandão Nasser Allam Maria Clotilde Henriques Tavares 《Journal of Behavioral and Brain Science》 2024年第5期135-160,共26页
Introduction: In the last thirty years, brain neuromodulation techniques have been used as an alternative to pharmacological treatment of neurological disorders. Parkinson’s disease (PD) is a neurodegenerative disord... Introduction: In the last thirty years, brain neuromodulation techniques have been used as an alternative to pharmacological treatment of neurological disorders. Parkinson’s disease (PD) is a neurodegenerative disorder leading to bradykinesia, rest tremor, postural changes, and non-motor symptoms such as depression, anxiety, sleep disorders, pain, and cognitive decline that compromises executive functions (EFs), responsible for the orderly execution of behaviors and tasks of daily life and intentional and directed actions. To this date, a few studies with transcranial direct current stimulation (tDCS) have shown beneficial effects in PD patients concerning specific motor and non-motor symptoms, targeting the motor cortex and/or prefrontal regions. Objective: The main objective of this study was to evaluate the effects of left prefrontal tDCS across a broad spectrum of motor and non-motor symptoms of PD using established validated scales. Method: Single-blind randomized clinical trial with 18 volunteers with PD, aged between 45 and 80 years (66.1 ± 9.65), who met inclusion and exclusion criteria. Participants were submitted to assessments of motor and non-motor functions employing psychometric scales and tests to evaluate EFs and were randomly divided into two groups: control (sham stimulation) and experimental (active stimulation). All participants were involved in three separate tDCS sessions. The anode was positioned over the left dorsolateral prefrontal cortex and the cathode over the right supraorbital region, with a direct current intensity of 2 mA, lasting 20 minutes. At the end of the three sessions, all participants were reassessed. Results: Significant effects of tDCS on non-motor functions were observed for cognition (verbal fluency of actions, clock copy test, appointment by visual confrontation, and verbal memory with immediate free recall) and subjective assessment of sleep quality (overall restlessness and discomfort in the arms and legs at night, leg and arm cramps at night and distressing dreams). There was also an improvement in the rate of errors and successes for congruent and incongruent stimuli of the Stroop Test. The beneficial effects on motor function were decreased rigidity, improved gait, and greater agility in the finger-tapping test. Conclusion: Three tDCS sessions showed positive results for participants with PD, producing significant improvements in various motor and non-motor functions, including sleep quality, cognition, and EFs. Additionally, the present results indicate that tDCS neuromodulation of the left dorsolateral prefrontal cortex region is feasible, safe, and provides significant objective benefits for PD patients. 展开更多
关键词 Parkinson’s Disease NEUROMODULATION Transcranial direct current Stimulation—tDCS Movement Disorders MOOD SLEEP COGNITION
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“Flow” Transcranial Direct Current Stimulation (tDCS) for Depression Treatment in a Primary Healthcare General Practice—An Open-Label Cohort Study Measuring Montgomery-Åsberg Depression Rating Scale (MADRS-S) Outcomes
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作者 Chris Griffiths Harmony Jiang +1 位作者 David Smart Azhar Zafar 《Open Journal of Psychiatry》 2024年第4期386-399,共14页
Background: Flow FL-100 is a transcranial direct current stimulation (tDCS) device self-administered by a patient at home in combination with a software application delivered wellbeing behaviour therapy training. tDCS... Background: Flow FL-100 is a transcranial direct current stimulation (tDCS) device self-administered by a patient at home in combination with a software application delivered wellbeing behaviour therapy training. tDCS has evidence of effectiveness in treating symptoms of depression. Purpose/Aim: This post marketing study evaluated the effect of Flow on depression for primary care general practice patients with depression symptoms. Methods: Open-label patient cohort design with no control group. Inclusion criteria were aged 18 years or over and reporting depression symptoms. Participants self-administered five 30 minute tDCS sessions per week for the first three weeks, and then 3 sessions per week following this. Three, six and ten week assessment with participant self-report measure: Montgomery- Åsberg Depression Rating Scale (MADRS-S). Results: MADRS-S remission rates were between 29% - 30% at three weeks, 33% - 34% at six-weeks and 50% at 10-weeks treatment. There was a significant improvement in MADRS-S with large effect sizes at all time points. Conclusions: Flow tDCS can be delivered through a primary healthcare general practice service and patients will choose to use. Flow tDCS provides an effective depression treatment in addition and as an alternative to antidepressants and psychotherapy. tDCS has evidence as an effective depression treatment, and the widespread availability of tDCS in primary care general practice should be considered. 展开更多
关键词 DEPRESSION Transcranial direct current Stimulation Wellbeing General Practice
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Self-Administered “Flow” Transcranial Direct Current Stimulation (tDCS) Depression Treatment in a Crisis Resolution & Home Treatment (CRT) Service: Functioning, and Health-Related Quality of Life Outcomes
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作者 Chris Griffiths Sherif Abdalla +1 位作者 Mark Mcconnochie Harmony Jiang 《Open Journal of Psychiatry》 2024年第S2期514-527,共14页
Background: Transcranial direct current stimulation (tDCS) has research evidence that it can reduce symptoms of depression. Flow FL-100 is a transcranial direct current stimulation (tDCS) device self-administered by a... Background: Transcranial direct current stimulation (tDCS) has research evidence that it can reduce symptoms of depression. Flow FL-100 is a transcranial direct current stimulation (tDCS) device self-administered by a patient at home in combination with a software application that delivers wellbeing behaviour therapy training. Purpose/aim: The purpose of this study was to investigate if Flow can be introduced to a Crisis Resolution & Home Treatment (CRT) service and the impact of Flow in treating depression. The study addresses the questions: 1) “what are the depression reliable improvement and remission rates?” and 2) “can Flow significantly reduce depressive symptoms and improve real world functioning (every-day, social and occupational functioning) and health-related quality of life?”. Methods: An open-label patient cohort design with no control group. Pre-intervention and 6-week follow-up intervention assessments using the participant self-report measures: Patient Health Questionnaire (PHQ-9), Work and Social Adjustment Scale (WSAS), and EuroQol five-dimension (EQ-5D-5L). Participants were 49 CRT patients, 19 males and 30 females, with an age range of 20 to 66 years, and average age of 42 years. Results: PHQ-9 reliable improvement and remission rates were 57.1% and 14.3%. PHQ-9 scores significantly improved, from 23.1 (SD 3.44) to 14.8 (SD 6.82) at 6 weeks, with a large effect size. PHQ-9 suicide/self-harm related question significantly improved from 2.51 (SD 0.77) to 1.08 (SD 1.17), with a large effect size. WSAS scores significantly improved, from 33.6 (SD 5.22) to 21.9 (SD 10.82) at 6 weeks, with a large effect size. EQ-5D-5L results showed significant improvements in the health index score, global assessment of health EQ-VAS from 34.2 (22.26) to 51.6 (24.95), and three EQ-5D-5L dimensions (“self-care”, “usual activity”, and “anxiety/depression”). Conclusion: A CRT service effectively integrated Flow tDCS treatment. Flow was beneficial in terms of improving functioning and quality of life and reducing depression symptoms and thoughts of suicide/self-harm. Flow FL100 tDCS and wellbeing behaviour therapy training could be offered through all CRT services to treat depression, reduce thoughts of suicide/self-harm, enable better functioning, and improve quality of life. 展开更多
关键词 DEPRESSION Quality of Life FUNCTIONING Transcranial direct current Stimulation (tDCS)
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Positive Effect of Transcranial Direct Current Stimulation on Visual Verbal Working Memory in Patients with Attention-Deficit/Hyperactivity Disorder
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作者 Tomoko Uchida Daisuke Matsuzawa +7 位作者 Tadashi Shiohama Katsunori Fujii Akihiro Shiina Masamitsu Naka Katsuo Sugita Eiji Shimizu Naoki Shimojo Hiromichi Hamada 《Open Journal of Psychiatry》 2024年第4期334-346,共13页
Background: Working memory is an executive function that plays an important role in many aspects of daily life, and its impairment in patients with attention-deficit/hyperactivity disorder (ADHD) affects quality of li... Background: Working memory is an executive function that plays an important role in many aspects of daily life, and its impairment in patients with attention-deficit/hyperactivity disorder (ADHD) affects quality of life. The dorsolateral prefrontal cortex (DLPFC) has been a good target site for transcranial direct current stimulation (tDCS) due to its intense involvement in working memory. In our 2018 study, tDCS improved visual-verbal working memory in healthy subjects. Objective: This study examines the effects of tDCS on ADHD patients, particularly on verbal working memory. Methods: We conducted an experiment involving verbal working memory of two modalities, visual and auditory, and a sustained attention task that could affect working memory in 9 ADHD patients. Active or sham tDCS was applied to the left DLPFC in a single-blind crossover design. Results: tDCS significantly improved the accuracy of visual-verbal working memory. In contrast, tDCS did not affect auditory-verbal working memory and sustained attention. Conclusion: tDCS to the left DLPFC improved visual-verbal working memory in ADHD patients, with important implications for potential ADHD treatments. 展开更多
关键词 Working Memory Attention-Deficit/Hyperactivity Disorder Dorsolateral Prefrontal Cortex Transcranial direct current Stimulation
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Transcranial direct current stimulation as early augmentation in adolescent obsessive compulsive disorder:A pilot proof-of-concept randomized control trial
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作者 Aditya Agrawal Vivek Agarwal +1 位作者 Sujita Kumar Kar Amit Arya 《World Journal of Clinical Pediatrics》 2024年第2期161-170,共10页
BACKGROUND Transcranial direct current stimulation(tDCS)is proven to be safe in treating various neurological conditions in children and adolescents.It is also an effective method in the treatment of OCD in adults.AIM... BACKGROUND Transcranial direct current stimulation(tDCS)is proven to be safe in treating various neurological conditions in children and adolescents.It is also an effective method in the treatment of OCD in adults.AIM To assess the safety and efficacy of tDCS as an add-on therapy in drug-naive adolescents with OCD.METHODS We studied drug-naïve adolescents with OCD,using a Children’s Yale-Brown obsessive-compulsive scale(CY-BOCS)scale to assess their condition.Both active and sham groups were given fluoxetine,and we applied cathode and anode over the supplementary motor area and deltoid for 20 min in 10 sessions.Reassessment occurred at 2,6,and 12 wk using CY-BOCS.RESULTS Eighteen adolescents completed the study(10-active,8-sham group).CY-BOCS scores from baseline to 12 wk reduced significantly in both groups but change at baseline to 2 wk was significant in the active group only.The mean change at 2 wk was more in the active group(11.8±7.77 vs 5.25±2.22,P=0.056).Adverse effects between the groups were comparable.CONCLUSION tDCS is safe and well tolerated for the treatment of OCD in adolescents.However,there is a need for further studies with a larger sample population to confirm the effectiveness of tDCS as early augmentation in OCD in this population. 展开更多
关键词 Adolescents Early augmentation Obsessive compulsive disorder SAFETY Transcranial direct current stimulation
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Effects of direct current electric field on corrosion behaviour of copper, Cl- ion migration behaviour and dendrites growth under thin electrolyte layer 被引量:11
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作者 黄华良 潘志权 +1 位作者 郭兴蓬 邱于兵 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第1期285-291,共7页
Effect of direct current electric field (DCEF) on corrosion behaviour of copper printed circuit board (PCB-Cu), Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using pote... Effect of direct current electric field (DCEF) on corrosion behaviour of copper printed circuit board (PCB-Cu), Cl-ion migration behaviour, dendrites growth under thin electrolyte layer was investigated using potentiodynamic polarization and scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS). Results indicate that DCEF decreases the corrosion of PCB-Cu;Cl-ions directionally migrate from the negative pole to the positive pole, and enrich on the surface of the positive pole, which causes serious localized corrosion; dendrites grow on the surface of the negative pole, and the rate and scale of dendrite growth become faster and greater with the increase of external voltage and exposure time, respectively. 展开更多
关键词 COPPER DENDRITES MIGRATION direct current electric field thin electrolyte layer copper printed circuit board
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Grain refinement of pure aluminum by direct current pulsed magnetic field and inoculation 被引量:6
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作者 陈航 接金川 +2 位作者 付莹 马红军 李廷举 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2014年第5期1295-1300,共6页
The combined effects of direct current pulsed magnetic field (DC-PMF) and inoculation on pure aluminum were investigated, the grain refinement behavior of DC-PMF and inoculation was discussed. The experimental resul... The combined effects of direct current pulsed magnetic field (DC-PMF) and inoculation on pure aluminum were investigated, the grain refinement behavior of DC-PMF and inoculation was discussed. The experimental results indicate that the solidification micro structure of pure aluminum can be greatly refined under DC-PMF. Refinement of pure aluminum is attributed to electromagnetic undercooling and forced convection caused by DC-PMF. With single DC-PMF, the grain size in the equiaxed zone is uneven. However, under DC-PMF, by adding 0.05% (mass fraction) Al5Ti-B, the grain size of the sample is smaller, and the size distribution is more uniform than that of single DC-PMF. Furthermore, under the combination of DC-PMF and inoculation, with the increase of output current, the grain size is further reduced. When the output current increases to 100 A, the average grain size can decrease to 113 μn. 展开更多
关键词 direct current pulsed magnetic field pure aluminum inoculation grain refinement solidification micro structure
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Finite element numerical simulation of 2.5D direct current method based on mesh refinement and recoarsement 被引量:3
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作者 张钱江 戴世坤 +3 位作者 陈龙伟 强建科 李昆 赵东东 《Applied Geophysics》 SCIE CSCD 2016年第2期257-266,416,417,共12页
To deal with the problem of low computational precision at the nodes near the source and satisfy the requirements for computational efficiency in inversion imaging and finite-element numerical simulations of the direc... To deal with the problem of low computational precision at the nodes near the source and satisfy the requirements for computational efficiency in inversion imaging and finite-element numerical simulations of the direct current method, we propose a new mesh refinement and recoarsement method for a two-dimensional point source. We introduce the mesh refinement and mesh recoarsement into the traditional structured mesh subdivision. By refining the horizontal grids, the singularity owing to the point source is minimized and the topography is simulated. By recoarsening the horizontal grids, the number of grid cells is reduced significantly and computational efficiency is improved. Model tests show that the proposed method solves the singularity problem and reduces the number of grid cells by 80% compared to the uniform grid refinement. 展开更多
关键词 direct current resistivity method mesh refinement and recoarsement finiteelement method
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Single Bubble Behavior in Direct Current Electric Field 被引量:11
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作者 彭耀 陈凤 +1 位作者 宋耀祖 陈民 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2008年第2期178-183,共6页
The investigation on bubble behavior in electric field helps to analyze the mechanism of electric enhancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct curre... The investigation on bubble behavior in electric field helps to analyze the mechanism of electric enhancement of boiling heat transfer. Experiments were performed to investigate the bubble deformation in direct current (DC) electric field with bubbles attached to the orifice. The air bubbles were slowly generated in the transformer oil pool at different orifices, so that the effect of flow on bubble shape was eliminated. The results showed that the bubbles were elongated and the departure volume decreased when the electric field was intensified. The major and minor axes, aspect ratio and departure volume increased with increasing the orifice diameter. Both the electric field and orifice size have great influence on bubble behavior. The bubble deformation was also simulated to compare with the experimental results. The numerical and experimental data qualitatively agree with each other. 展开更多
关键词 electrohydrodynamic enhancement multiphase flow bubble behavior direct current electric field
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Solidification Behavior of Immiscible Alloys under the Effect of a Direct Current 被引量:5
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作者 Hongxiang Jiang Jiuzhou Zhao Jie He 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2014年第10期1027-1035,共9页
Directional solidification experiments were carried out with Al-Pb alloys under the effect of a direct current (DC). The experimental results show that the DC causes a migration of the minority phase droplets (MPDs... Directional solidification experiments were carried out with Al-Pb alloys under the effect of a direct current (DC). The experimental results show that the DC causes a migration of the minority phase droplets (MPDs) from the middle part to the surface region of the sample, Samples with either a finely dispersed microstructure or a shell/ core structure were obtained by solidifying the alloy under the effect of the properly selected DC densities, A model was developed to describe the microstructure evolution in an immiscible alloy directionaliy solidified under the effect of the DC. The microstructure formation in the AI-Pb alloys was calculated. The numerical results are in favorable agreement with the experimental ones. They demonstrate that the DC affects the microstructure formation mainly through changing the spatial motions of the MPDs and the temperature field of the melt in front of the solid/liquid interface. The formation mechanisms of the finely dispersed microstructure as well as the shell/core structure were sufficiently clarified. 展开更多
关键词 Rapid directional solidification direct current Finely dispersed microstructure Shell/core structure
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Harvesting Environment Mechanical Energy by Direct Current Triboelectric Nanogenerators 被引量:8
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作者 Chuncai Shan Kaixian Li +1 位作者 Yuntao Cheng Chenguo Hu 《Nano-Micro Letters》 SCIE EI CAS CSCD 2023年第8期381-404,共24页
As hundreds of millions of distributed devices appear in every corner of our lives for information collection and transmission in big data era,the biggest challenge is the energy supply for these devices and the signa... As hundreds of millions of distributed devices appear in every corner of our lives for information collection and transmission in big data era,the biggest challenge is the energy supply for these devices and the signal transmission of sensors.Triboelectric nanogenerator(TENG)as a new energy technology meets the increasing demand of today’s distributed energy supply due to its ability to convert the ambient mechanical energy into electric energy.Meanwhile,TENG can also be used as a sensing system.Direct current triboelectric nanogenerator(DC-TENG)can directly supply power to electronic devices without additional rectification.It has been one of the most important developments of TENG in recent years.Herein,we review recent progress in the novel structure designs,working mechanism and corresponding method to improve the output performance for DC-TENGs from the aspect of mechanical rectifier,tribovoltaic effect,phase control,mechanical delay switch and air-discharge.The basic theory of each mode,key merits and potential development are discussed in detail.At last,we provide a guideline for future challenges of DC-TENGs,and a strategy for improving the output performance for commercial applications. 展开更多
关键词 Triboelectric nanogenerators direct current Working mechanism
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Transcranial direct current stimulation for auditory verbal hallucinations:a systematic review of clinical trials 被引量:7
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作者 Samaneh Rashidi Myles Jones +3 位作者 Eric Murillo-Rodriguez Sergio Machado Youguo Hao Ali Yadollahpour 《Neural Regeneration Research》 SCIE CAS CSCD 2021年第4期666-671,共6页
Transcranial direct current stimulation(tDCS)has been reportedly beneficial for different neurodegenerative disorders.tDCS has been reported as a potential adjunctive or alternative treatment for auditory verbal hallu... Transcranial direct current stimulation(tDCS)has been reportedly beneficial for different neurodegenerative disorders.tDCS has been reported as a potential adjunctive or alternative treatment for auditory verbal hallucination(AVH).This study aims to review the effects of tDCS on AVH in patients with schizophrenia through combining the evidence from randomized clinical trials(RCTs).The databases of PsycINFO(2000–2019),PubMed(2000–2019),EMBASE(2000–2019),CINAHL(2000–2019),Web of Science(2000–2019),and Scopus(2000–2019)were systematically searched.The clinical trials with RCT design were selected for final analysis.A total of nine RCTs were eligible and included in the review.Nine RCTs were included in the final analysis.Among them,six RCTs reported a significant reduction of AVH after repeated sessions of tDCS,whereas three RCTs did not show any advantage of active tDCS over sham tDCS.The current studies showed an overall decrease of approximately 28%of AVH after active tDCS and 10%after sham tDCS.The tDCS protocols targeting the sensorimotor frontal-parietal network showed greater treatment effects compared with the protocols targeting other regions.In this regard,cathodal tDCS over the left temporoparietal area showed inhibitory effects on AVHs.The most effective tDCS protocol on AVHs was twice-daily sessions(2 mA,20-minute duration)over 5 consecutive days(10 sessions)with the anode over the left dorsolateral prefrontal cortex and the cathode over the left temporal area.Some patient-specific and diseasespecific factors such as young age,nonsmoking status,and higher frequencies of AVHs seemed to be the predictors of treatment response.Taken together,the results of tDCS as an alternative treatment option for AVH show controversy among current literatures,since not all studies were positive.However,the studies targeting the same site of the brain showed that the tDCS could be a promising treatment option to reduce AVH.Further RCTs,with larger sample sizes,should be conducted to reach a conclusion on the efficacy of tDCS for AVH and to develop an effective therapeutic protocol for clinical setting. 展开更多
关键词 auditory verbal hallucinations dorsolateral prefrontal cortex effective protocol randomized clinical trial schizophrenia temporoparietal area transcranial direct current stimulation treatment efficacy
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Combining electroacupuncture and transcranial direct current stimulation as an adjuvant therapy enhances spontaneous conversation and naming in subacute vascular aphasia:A retrospective analysis 被引量:5
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作者 Samwel Sylvester Msigwa Yan Li +1 位作者 Xiang-lin Cheng Fen Cao 《Journal of Integrative Medicine》 SCIE CAS CSCD 2022年第3期244-251,共8页
Objective:Emerging evidence shows the effectiveness of speech and language therapy(SLT);however,precise therapeutic parameters remain unclear.Evidence for the use of adjunctive transcranial direct current stimulation(... Objective:Emerging evidence shows the effectiveness of speech and language therapy(SLT);however,precise therapeutic parameters remain unclear.Evidence for the use of adjunctive transcranial direct current stimulation(t DCS)to treat post-stroke aphasia(PSA)is promising;however,the utility of combining t DCS and electroacupuncture(EA)has not yet been analyzed.This study assessed the therapeutic consequences of EA and t DCS coupled with SLT in subacute PSA patients who were also undergoing hyperbaric oxygen therapy(HBOT).Methods:A retrospective analysis was conducted on subacute(<6 months)PSA patients who were divided into three groups:patients who received EA plus t DCS(acupuncture group),patients who underwent t DCS(t DCS group),and patients who experienced conventional therapy(HBOT+SLT).All subjects underwent 21 days of treatment and also received conventional treatment.The aphasia battery of Chinese(ABC)was used to score pre-and post-intervention status.Results:The analysis comprised 238 patients.Cerebral infarction was the most frequent stroke type(137[57.6%]),while motor(66[27.7%])and global aphasia(60[25.2%])were the most common types of aphasia.After 21 days of intervention,the ABC scores of all patients were improved.The acupuncture group had the highest ABC scores,but only repetition,naming,and spontaneous speech were statistically improved(P<0.01).Post-hoc tests revealed significant improvement in word retrieval in the acupuncture and t DCS groups(P<0.01,P=0.037),while the acupuncture group had additional significant improvement in spontaneous conversation(P<0.01).Conclusion:Combining acupuncture and t DCS as an adjuvant therapy for subacute PSA led to significant spontaneous speech and word retrieval improvements.Future prospective,multi-ethnic,multi-center trials are warranted. 展开更多
关键词 APHASIA Stroke rehabilitation Acupuncture ELECTROACUPUNCTURE Transcranial direct current stimulation Speech therapy
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