期刊文献+
共找到25,057篇文章
< 1 2 250 >
每页显示 20 50 100
A novel dual-channel thermo-optic locking method for the whispering gallery mode microresonator
1
作者 范文杰 刘文耀 +6 位作者 潘梓文 王蓉 刘来 邢恩博 周彦汝 唐军 刘俊 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第5期438-444,共7页
Mode locking can be effectively achieved by using the thermo-optic effects in the whispering gallery mode(WGM)optical microcavity,without the help of external equipment.Therefore,it has the advantages of small size,lo... Mode locking can be effectively achieved by using the thermo-optic effects in the whispering gallery mode(WGM)optical microcavity,without the help of external equipment.Therefore,it has the advantages of small size,low integration costs,and self-locking,which shows great potential for application.However,the conventional single-channel microcavity thermal-locking method that relies solely on internal thermal balance will inevitably be disturbed by the external environment.This limitation affects the locking time and stability.Therefore,in this paper,we propose a new method for closed-loop thermal locking of a dual-channel microcavity.The thermal locking of the signal laser and the thermal regulation of the control laser are carried out respectively by synchronously drawing a dual-path tapered fiber.The theoretical model of the thermal dynamics of the dual-channel microcavity system is established,and the influence of the control-laser power on the thermal locking of the signal laser is confirmed.The deviation between the locking voltage of the signal laser and the set point value is used as a closed-loop feedback parameter to achieve long-term and highly stable mode locking of the signal laser.The results show that in the 2.63 h thermal-locking test,the locking stability is an order of magnitude higher than that of the single tapered fiber.This solution addresses the issue of thermal locking being disrupted by the external environment,and offers new possibilities for important applications such as spectroscopy and micro-optical sensor devices. 展开更多
关键词 optical microcavity thermo-optic locking thermal nonlinearity effect
下载PDF
Early Treatment Outcome of Humeral Shaft Fracture Non-Union in Adults: Comparative Study of Plating versus Interlocking Nailing
2
作者 Abdullallahi Bello Galadima Lukman Olalekan Ajiboye +1 位作者 Muhammad Nuhu Salihu Isha Nurudeen 《Health》 2024年第4期371-381,共11页
Background: Fractures of humeral shaft in adults are common injuries. Humeral shafts non-union either from late presentation after initial treatment by traditional bone setters or failed non-operative orthodox care is... Background: Fractures of humeral shaft in adults are common injuries. Humeral shafts non-union either from late presentation after initial treatment by traditional bone setters or failed non-operative orthodox care is a major problem in this part of the world. This non-union is a major treatment challenge with increased cost of care and morbidity in this part of the world. Humeral shaft non-union can be treated with locked intra-medullary nailing (LIMN) or dynamic compression plating (DCP). Study on comparison of these methods of fixation in this part of the world is scarce in literature search, hence the reason for this study. Objective: The objectives of this study are: (1) to compare early clinical outcome following fixation of humeral shaft fracture nonunion with DCP versus LIMN;(2) to compare the time of radiologic fracture union of DCP with LIMN;(3) to compare complications following fixation of humeral shaft fracture nonunion with DCP versus LIMN. Patients and Methods: This was a randomized control study done for 2 years in which fifty adult patients with humeral shaft non-union were recruited. The patients were grouped into 2 (P = DCP & N = LIMN). Forty five of the patients completed the follow up periods of the study and then analyzed. The P group had ORIF with DCP while the N group had ORIF with LIMN. Both groups had grafting with cancellous bones. Each patient was followed up for a period of 6 months at the time which radiographic union is expected. Any patient without clinical and/or radiographic evidence of union after six months of surgery was diagnosed as having recurrent non-union. The data generated was analyzed using SPSS Version 23. The results were presented in charts and tables. The paired t-test was used while considering p value Result: Forty five patients completed follow up. There was a male preponderance (4:1), right humerus predominated (3:2). Motor vehicular accidents were the commonest cause of the fractures (62%). Most non-union fractures occurred at the level of the middle 3<sup>rd</sup> of the humeral shaft (60%). Failed TBS treatment was the commonest indication for the osteosynthesis (71%). More patients had plating (53%) compared to 47% who had LIMN. Most patients (93.4%) had union between 3 to 6 months irrespective of fixation type with no significant statistical difference between the union rate of DCP and LIMN (p value 0.06) with similar functional outcome and complication rates irrespective of the type of fixation. Conclusion: This study showed that the success rates in term of fracture union, outcome functional grades and complication rates were not directly dependent on the types of the fixation: plating or locked intra-medullary nailing. 展开更多
关键词 Humeral Shaft NON-UNION Dynamic Compression Plating Locked Intra-Medullary Nailing Early Treatment Outcome Early Outcome
下载PDF
Unlocking Cellular Mysteries:Advancements in Single-Cell Omics Analysis with Genome-Scale Metabolic Modeling
3
《Bulletin of the Chinese Academy of Sciences》 2024年第1期52-52,共1页
The widespread applications of single-cell technologies have generated a large amount of single-cell data,resulting in a growing need for single-cell data analysis and interpretation methods.While methods such as mach... The widespread applications of single-cell technologies have generated a large amount of single-cell data,resulting in a growing need for single-cell data analysis and interpretation methods.While methods such as machine learning allow for single-cell data analysis,they cannot interpret the data very well. 展开更多
关键词 methods. METABOLIC locking
下载PDF
Locking plates for distal fibula fractures in young and elderly patients:A retrospective study 被引量:1
4
作者 Francesco Roberto Evola Giovanni Francesco Di Fede +3 位作者 Giuseppe Evola Martina Barchitta Antonella Agodi Gianfranco Longo 《World Journal of Orthopedics》 2023年第7期540-546,共7页
BACKGROUND Ankle fractures are common injuries in the young and elderly populations.To prevent post-traumatic arthritis,an anatomic reconstruction of the ankle structure is mandatory.Open reduction and internal fixati... BACKGROUND Ankle fractures are common injuries in the young and elderly populations.To prevent post-traumatic arthritis,an anatomic reconstruction of the ankle structure is mandatory.Open reduction and internal fixation is the treatment of choice among orthopaedics.Conventional plates allow stability of the fracture if bone quality is present.Locking plates might offer an advantage for the treatment of lateral malleolar fracture in patients with comminution,severe instability,distal fractures,or osteoporotic bone.Our hospital introduced a new locking plate for fracture of the distal fibula.AIM To evaluate locking plates in terms of outcomes and complications in young and elderly patients.METHODS We retrospectively reviewed a total of 67 patients treated for displaced distal fibula fractures.Demographic data,number of comorbidities,use of inter fragmentary screw,complication,time of fracture healing,partial or full weight bearing,and reoperation were recorded for all patients.Clinical outcome was assessed by the American Orthopedic Foot and Ankle Society clinical scoring system.Radiographs were obtained at 4,8,12,16,20,and 24 wk until radiographic union was obtained.RESULTS All patients displayed complete bony union on radiographic assessment,and no patients developed any serious complications.We observed two superficial infections,one delayed wound healing,and two plate intolerances.Significant differences were observed between the two age groups in terms of radiographic healing(11.9 wk in younger patients vs 13.7 wk in older patients;P=0.011)and in the American Orthopedic Foot and Ankle Society score at 6 mo after surgery(88.2 in younger patients vs 86.0 in older patients;P=0.001)and at 12 mo after surgery(92.6 in younger patients vs 90.0 in older patients;P=0.000).CONCLUSION Locking plates provide a stable and rigid fixation in multifragmentary and comminuted fractures or in the presence of poor bone quality. 展开更多
关键词 Ankle fracture locking plate Distal fibula fracture OUTCOME COMPLICATIONS OSTEOPOROSIS
下载PDF
Perspectives of spin-valley locking devices
5
作者 陶玲玲 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第10期15-21,共7页
Valleytronics is an emerging field of research which utilizes the valley degree of freedom to encode information.However,it is technically nontrivial to produce a stable valley polarization and to achieve efficient co... Valleytronics is an emerging field of research which utilizes the valley degree of freedom to encode information.However,it is technically nontrivial to produce a stable valley polarization and to achieve efficient control and manipulation of valleys.Spin–valley locking refers to the coupling between spin and valley degrees of freedom in the materials with large spin–orbit coupling(SOC)and enables the manipulation of valleys indirectly through controlling spins.Here,we review the recent advances in spin–valley locking physics and outline possible device implications.In particular,we focus on the spin–valley locking induced by SOC and external electric field in certain two-dimensional materials with inversion symmetry and demonstrate the intriguing switchable valley–spin polarization,which can be utilized to design the promising electronic devices,namely,valley-spin valves and logic gates. 展开更多
关键词 spin–valley locking SPINTRONICS valleytronics spin–orbit coupling
下载PDF
An injection-locking diode laser at 671 nm with a wide tuning range up to 6 GHz
6
作者 宋红芳 沈玥 李可 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第9期60-66,共7页
We present a compact injection-locking diode laser module to generate 671 nm laser light with a high output power up to 150 m W.The module adopts a master-slave injection-locking scheme,and the injection-locking state... We present a compact injection-locking diode laser module to generate 671 nm laser light with a high output power up to 150 m W.The module adopts a master-slave injection-locking scheme,and the injection-locking state is monitored using the transmission spectrum from a Fabry-Perot interferometer.Beat frequency spectrum measurement shows that the injection-locked slave laser has no other frequency components within the 150-MHz detection bandwidth.It is found that without additional electronic feedback,the slave laser can follow the master laser over a wide range of 6 GHz.All the elements of the module are commercially available,which favors fast construction of a complete 671-nm laser system for the preparation of cold^(6)Li atoms with only one research-grade diode laser as the seeding source. 展开更多
关键词 injection lock diode laser ^(6)Li atoms
下载PDF
Knee locking caused by osteochondroma of the proximal tibia adjacent to the pes anserinus:A case report
7
作者 Tatsuru Sonobe Michiyuki Hakozaki +3 位作者 Yohei Matsuo Yojiro Takahashi Katsuhiro Yoshida Shinichi Konno 《World Journal of Clinical Cases》 SCIE 2023年第23期5595-5601,共7页
BACKGROUND Osteochondroma is one of the most common benign bone tumors,and it may cause bone and joint deformities and limited range of motion of an adjacent joint.The pes anserinus region is one of the most frequent ... BACKGROUND Osteochondroma is one of the most common benign bone tumors,and it may cause bone and joint deformities and limited range of motion of an adjacent joint.The pes anserinus region is one of the most frequent sites of osteochondroma,but knee locking caused by osteochondromas in the pes anserinus region is extremely rare.CASE SUMMARY We describe a 13-year-old Japanese girl’s extra-articular knee locking that occurred when the semitendinosus tendon got caught in osteochondroma that had developed in the pes anserinus region.The osteochondroma was surgically resected.The postoperative outcome has been excellent,with no recurrence of knee locking or tumor one-year post-surgery.CONCLUSION When a young person develops knee locking,the possibility of extra-articular as well as intra-articular locking should be considered.Osteochondroma,one of the causes of extra-articular locking,can be treated with surgery with good postoperative results. 展开更多
关键词 Extra-articular knee locking Impingement OSTEOCHONDROMA Pes anserinus Tibia Surgery Case report
下载PDF
Triggering,clicking,locking and crepitus of the finger:A comprehensive overview
8
作者 Pieter W Jordaan Raymond Klumpp Marco Zeppieri 《World Journal of Orthopedics》 2023年第10期733-740,共8页
Triggering,locking,clicking,and crepitus of the fingers are common symptoms patients present with.Even though crepitus and triggering can occur as part of the same underlying diagnosis,it is important to differentiate... Triggering,locking,clicking,and crepitus of the fingers are common symptoms patients present with.Even though crepitus and triggering can occur as part of the same underlying diagnosis,it is important to differentiate between them,as they usually indicate different possible diagnoses.The differential diagnoses that should be considered include trigger finger,metacarpophalangeal joint(MCPJ)arthritis,fractures or dislocations,extensor digitorum communis subluxation or dislocation,locked MCPJ,avascular necrosis of the metacarpal head,and Dupuytren’s disease.A thorough clinical examination with appropriate special investigations can permit the clinician to make the correct diagnosis.Appropriate management of a confirmed diagnosis is successful in providing symptomatic improvement. 展开更多
关键词 Trigger finger locking Crepitus Metacarpophalangeal joint DISLOCATION Differential diagnosis
下载PDF
Unlocking the Brain’s Gateway to Methamphetamine Addiction
9
作者 YAN Fusheng 《Bulletin of the Chinese Academy of Sciences》 2023年第4期215-216,共2页
What secret molecular key enables methamphetamine,or meth for short,to ruthlessly hijack the brain’s reward system,leading countless individuals down spiral paths of addiction?Thanks to innovative research reported t... What secret molecular key enables methamphetamine,or meth for short,to ruthlessly hijack the brain’s reward system,leading countless individuals down spiral paths of addiction?Thanks to innovative research reported this month in Nature,we finally have critical clues. 展开更多
关键词 finally enable locking
下载PDF
高渗透率下基于并网逆变器阻抗重塑的锁相环设计方法 被引量:3
10
作者 杨明 杨倬 +2 位作者 李玉龙 赵月圆 朱军 《电工技术学报》 EI CSCD 北大核心 2024年第2期554-566,共13页
针对锁相环、电网阻抗与并网逆变器相互耦合所引发的系统稳定性下降问题。首先,建立考虑电网阻抗的锁相环控制结构模型,通过分析锁相环闭环传递函数可知,电网阻抗会使锁相环系统产生右半平面闭环极点,严重影响锁相环与逆变器系统的稳定... 针对锁相环、电网阻抗与并网逆变器相互耦合所引发的系统稳定性下降问题。首先,建立考虑电网阻抗的锁相环控制结构模型,通过分析锁相环闭环传递函数可知,电网阻抗会使锁相环系统产生右半平面闭环极点,严重影响锁相环与逆变器系统的稳定性。其次,通过分析逆变器系统输出阻抗,说明锁相环所引入的负阻抗是逆变器系统稳定裕度下降的主要原因。鉴于此,该文提出一种新型锁相环设计方法,理论分析表明,所提方法既能够保证高渗透率下锁相环具有高鲁棒性,又能够对逆变器系统输出阻抗进行重塑,有效拓宽系统对电网阻抗的适应范围。最后,通过仿真与实验验证所提新型锁相环设计方法的有效性。 展开更多
关键词 高渗透率 并网逆变器 锁相环 阻抗重塑 鲁棒性
下载PDF
弱电网下基于电网电压前馈的并网逆变器阻抗重塑控制策略 被引量:3
11
作者 杨明 杨倬 +1 位作者 李玉龙 朱军 《电工技术学报》 EI CSCD 北大核心 2024年第8期2553-2566,共14页
弱电网下,锁相环在基波以上频段引入的负阻特性,会降低系统输出阻抗的相位,严重影响系统稳定性。鉴于此,该文通过系统控制框图等效变换,推导得到可以消除锁相环负阻特性的电网电压前馈函数,进而提出一种基于电网电压前馈控制的并网逆变... 弱电网下,锁相环在基波以上频段引入的负阻特性,会降低系统输出阻抗的相位,严重影响系统稳定性。鉴于此,该文通过系统控制框图等效变换,推导得到可以消除锁相环负阻特性的电网电压前馈函数,进而提出一种基于电网电压前馈控制的并网逆变器阻抗重塑控制策略。同时,为了提高该策略的普适性,该文利用函数近似和多目标约束为电网电压前馈函数的优化提供两种设计方法,并从系统基波电流跟踪性能、并网功率因数等方面进行误差分析,从而证明其函数优化设计方法的可行性。理论分析表明,优化后的电网电压前馈控制策略,可以有效地对系统输出阻抗相位特性进行重塑,很大程度上拓宽了系统对电网阻抗的适应范围。最后,通过仿真与实验验证所提控制策略的有效性。 展开更多
关键词 弱电网 并网逆变器 阻抗重塑 锁相环 稳定性
下载PDF
多种通航建筑物组合布置的通过时间研究 被引量:1
12
作者 董霞 赵凯 +1 位作者 吕小龙 张震 《水运工程》 2024年第1期97-104,共8页
山区航道高水头通航建筑物多采用船闸、升船机、隧洞和中间渠道组合布置的形式。多种通航建筑物组合布置时,各通航建筑物的通过能力相互制约和影响,计算较为复杂。结合工程实际,在通过能力计算中,分析了通过各建筑物时间的匹配性及其对... 山区航道高水头通航建筑物多采用船闸、升船机、隧洞和中间渠道组合布置的形式。多种通航建筑物组合布置时,各通航建筑物的通过能力相互制约和影响,计算较为复杂。结合工程实际,在通过能力计算中,分析了通过各建筑物时间的匹配性及其对通航效率的影响,指出在组合布置通航建筑物时,应以船闸或升船机1次运行时间为基础,复核计算通航隧洞、辅助闸门等其他通航建筑物的1次运行时间是否小于基础时间,当大于基础时间时,应合理调整组合形式、布置形式和建设规模,成果可为类似工程提供参考。 展开更多
关键词 船闸 升船机 隧洞 船闸通过能力 临界航速
下载PDF
Fixation of Calcaneal Tuberosity Beavis II Fracture in Elderly Patients Using Locking Plate Combined with Tension Screw
13
作者 De-Jian Li Jia-Wen He +2 位作者 Jian-Hua Zhou Cheng-Qing Yi Qi-Kai Huang 《Biomedical Engineering Communications》 2023年第1期24-28,共5页
Background:Calcaneus is the largest bone of foot and the main load-bearing structure of heel.The incidence of simple calcaneal tubercle avulsion fracture is low,accounting for about 1%to 3%of all calcaneal fractures.B... Background:Calcaneus is the largest bone of foot and the main load-bearing structure of heel.The incidence of simple calcaneal tubercle avulsion fracture is low,accounting for about 1%to 3%of all calcaneal fractures.Beavis II fracture has large bone fracture,obvious displacement,obvious soft tissue irritation,and often leads to skin necrosis.It needs surgical treatment,reduction and fixation as soon as possible.Although open reduction and tension screw internal fixation is used for Beavis II calcaneal tubercle fracture,but the failure rate is more common.Methods:This study retrospectively analyzed the surgical treatment of calcaneal tubercle Beavis II fracture over 55 years old in our hospital from January 2013 to January 2019.The patients were treated with tension screw combined with locking plate,and followed up and analyzed.Results:12 patients in this group were followed up for 12 to 36 months(mean 20 months).After operation,the fracture healed smoothly in all patients,the healing time was 8 to 12 weeks(mean 10.7 weeks),and there were no complications such as poor incision healing,fracture displacement,internal fixation loosening,fracture and so on.When the patients were followed up 18 weeks after operation,the AOFAS score was 47 to 100,with an average of 91.1,of which 8 cases were excellent,3 good and 1 poor,with an excellent and good rate of 91.7%.Conclusion:Our hospital has been treated with tension screw combined with locking plate,fixed firmly,can early functional exercise,achieved good results. 展开更多
关键词 calcaneal tubercle Beavis II fracture locking plate tension screw elderly patients
下载PDF
页岩储层防水锁聚合物水基钻井液体系研究 被引量:1
14
作者 贾东林 闫海建 +2 位作者 黄小峰 夏海英 樊建建 《当代化工》 CAS 2024年第3期631-635,共5页
开发一种适用于页岩储层的水基钻井液体系,以优化钻井过程中的页岩稳定性和防水锁效果。通过页岩滚动回收率、线性膨胀率测试以评价不同处理剂的效果。结果表明:0.5%WEDM+1.5%SFTH复配体系可显著提高页岩的回收率,同时最大线性膨胀率由3... 开发一种适用于页岩储层的水基钻井液体系,以优化钻井过程中的页岩稳定性和防水锁效果。通过页岩滚动回收率、线性膨胀率测试以评价不同处理剂的效果。结果表明:0.5%WEDM+1.5%SFTH复配体系可显著提高页岩的回收率,同时最大线性膨胀率由37.6%降至16.80%。封堵剂CMS在控制滤失量方面表现出色,包被剂KPAM在提高钻井液稳定性和降低滤失量方面具有显著效果。防水锁水基钻井液配方为:4%基浆+1.0%WEDM+1.5%SFTH+1.5%CMS+0.3%KPAM+2.0%op-10。该体系在高温高压条件下展现出了优异的流变特性和滤失控制能力,特别是在抗温性和抗污染性方面表现卓越。该体系在150℃高温下保持了良好的稳定性,且对NaCl和CaCl_(2)的抗污染能力强。在储层保护方面,该体系能有效减少钻井液对储层的伤害,实现高达85.69%的渗透率恢复率,同时形成的泥饼质量良好。研究成果对于页岩气开采具有重要意义。 展开更多
关键词 页岩 防水锁剂 储层保护 性能评价
下载PDF
锁定钢板联合皮质螺钉内固定治疗踝关节骨折伴下胫腓分离对踝关节功能及生活质量的影响 被引量:2
15
作者 韦志坤 王旭东 +3 位作者 杨金杰 牛朋彦 邵菲 任少海 《临床外科杂志》 2024年第1期71-74,共4页
目的 探讨锁定钢板联合皮质螺钉内固定治疗踝关节骨折伴下胫腓分离对踝关节功能及生活质量的影响。方法 2020年5月~2021年12月我院收治的踝关节骨折伴下胫腓分离病人120例,依据随机数字表法将其分为对照组和观察组,每组各60例。对照组... 目的 探讨锁定钢板联合皮质螺钉内固定治疗踝关节骨折伴下胫腓分离对踝关节功能及生活质量的影响。方法 2020年5月~2021年12月我院收治的踝关节骨折伴下胫腓分离病人120例,依据随机数字表法将其分为对照组和观察组,每组各60例。对照组采用单纯皮质螺钉固定治疗,观察组采用锁定钢板联合皮质螺钉内固定治疗。术前、术后6个月对两组恢复功能对比,比较X线片、手术时间、愈合时间、术中失血量,术后并发症,生活能力(BI)评估两组病人生活能力。依照美国足踝外科协会评分系统评估病人踝关节功能。结果 术前两组病人关节功能无差异(P>0.05),术后,对照组最远行走评分(15.89±0.85)分、足部对线评分(15.06±0.71)分、疼痛反应评分(29.03±4.48)分、地面行走评分(15.65±0.59)分;观察组分别为(16.19±0.87)分、(15.29±0.76)分、(31.24±4.55)分、(15.96±0.68)分。观察组最远行走、足部对线、疼痛反应、地面步行高于对照组,差异有统计学意义(P<0.05)。与对照组比较,观察组术中出血量少,愈合时间较短,差异有统计学意义(P<0.05)。术前两组BI指数比较,差异无统计学意义(P>0.05);观察组术后BI指数高于对照组,两组比较,差异有统计学意义(P<0.05)。两组并发症总发生率比较无差异(P>0.05)。结论 锁定钢板联合皮质螺钉内固定技术治疗踝关节骨折合并下胫腓分离,可改善踝关节功能,降低术中出血量,促进愈合,提高生活能力。 展开更多
关键词 踝关节骨折 下胫腓分离 锁定钢板 皮质螺钉内固定 踝关节功能
下载PDF
基于改进正交锁相环的永磁同步电机无位置传感器控制 被引量:1
16
作者 吴翔 陈硕 +2 位作者 李佳 张甲哲 张晓 《电工技术学报》 EI CSCD 北大核心 2024年第2期475-486,共12页
针对传统正交锁相环(QPLL)应用于永磁同步电机无位置传感器控制中存在的反转失效与加、减速工况下出现显著的转子位置直流偏移误差问题,该文提出一种改进的正交锁相环(IQPLL)。其通过重构鉴相器环节,使得鉴相器的输出与永磁同步电机的... 针对传统正交锁相环(QPLL)应用于永磁同步电机无位置传感器控制中存在的反转失效与加、减速工况下出现显著的转子位置直流偏移误差问题,该文提出一种改进的正交锁相环(IQPLL)。其通过重构鉴相器环节,使得鉴相器的输出与永磁同步电机的转向不再相关,从而解决传统QPLL在电机反转时估算转子位置出现180°偏差的问题。此外,在新型鉴相器结构下,设计前馈环路以补偿加、减速工况下的位置直流偏移误差。并建立了IQPLL的小信号模型,根据系统的频率响应特性给出了IQPLL的参数设计方法。实验结果表明,相对于传统的QPLL,所提出的IQPLL可实现永磁同步电机无位置传感器控制正、反转稳定运行,并有效抑制了加、减速工况下的转子位置直流偏移误差。 展开更多
关键词 永磁同步电机 正交锁相环 无位置传感器控制
下载PDF
钢结构模块新型自锁-可解锁式连接节点的抗拉研究 被引量:1
17
作者 刘燕 陈洋 +2 位作者 刘兴旺 祖金若 孟庆恺 《兵器材料科学与工程》 CAS CSCD 北大核心 2024年第3期49-58,共10页
为提高建筑用钢结构模块的施工效率、实现模块单元的快捷装配与拆卸,提出一种新型自锁-可解锁式连接节点方法,用Abaqus数值模拟软件建立了节点的精细化与半精细化有限元模型,探究了摩擦因数对节点抗拉承载性能的影响。选取上限位板厚度... 为提高建筑用钢结构模块的施工效率、实现模块单元的快捷装配与拆卸,提出一种新型自锁-可解锁式连接节点方法,用Abaqus数值模拟软件建立了节点的精细化与半精细化有限元模型,探究了摩擦因数对节点抗拉承载性能的影响。选取上限位板厚度、下限位板厚度和上部滑块宽度为关键参数进行有限元模拟,研究各参数对节点抗拉承载力及破坏模式的影响。最后与实际节点抗拉承载力进行对比。结果表明:当摩擦因数为0.3时,新型节点承受最大拉力为1345.49 kN,较角件旋转式连接节点提升约为152%。节点抗拉承载力受上部滑块宽度影响较大,受上限位板厚度与下限位板厚度影响相对小。当上、下限位板厚度均为25mm时,在10~12mm内增加上部滑块宽度可提升节点承载拉力。 展开更多
关键词 钢结构模块 自锁-可解锁式连接节点 抗拉性能 数值模拟
下载PDF
抚河疏山水利枢纽船闸通航水流条件研究 被引量:2
18
作者 付旭辉 何京霖 +3 位作者 张波 唐荣岭 刘予希 杜洪源 《水运工程》 2024年第2期72-78,共7页
为满足水运需求,解决船闸引航道口门区受河段地形和涉河建筑物影响而导致的通航条件困难等问题,保障船舶安全通行,以抚河疏山水利枢纽船闸工程为例,采用数值模拟方法,对枢纽船闸上游引航道口门区通航条件进行计算分析,针对不良流态问题... 为满足水运需求,解决船闸引航道口门区受河段地形和涉河建筑物影响而导致的通航条件困难等问题,保障船舶安全通行,以抚河疏山水利枢纽船闸工程为例,采用数值模拟方法,对枢纽船闸上游引航道口门区通航条件进行计算分析,针对不良流态问题提出优化方案措施,并对方案前后枢纽通航条件进行对比分析。研究表明,调整船闸平面布置等措施对改善设计阶段的枢纽船闸上引航道口门区通航条件是有效的。研究成果可为抚河疏山水利枢纽船闸工程通航及其他类似河段工程提供技术支持。 展开更多
关键词 船闸 引航道 通航水流条件 数学模型
下载PDF
弱电网下光伏并网系统锁相环参数自适应控制 被引量:1
19
作者 武海涛 张宁宁 +3 位作者 曹志轩 温素芳 李磊 李会珍 《电网与清洁能源》 CSCD 北大核心 2024年第1期52-61,共10页
针对弱电网下PLL(phase-looked loop,PLL)会使并网逆变器的稳定性下降问题,提出一种锁相环带宽自适应控制策略来实现锁相环参数依据电网实时阻抗值来获得最优的控制参数,保证系统最佳控制性能和稳定运行,从而提升跟网型逆变器在弱电网... 针对弱电网下PLL(phase-looked loop,PLL)会使并网逆变器的稳定性下降问题,提出一种锁相环带宽自适应控制策略来实现锁相环参数依据电网实时阻抗值来获得最优的控制参数,保证系统最佳控制性能和稳定运行,从而提升跟网型逆变器在弱电网下的对电网阻抗的适应能力。利用PSCAD/EMTDC进行仿真验证,仿真结果证明自适应控制策略正确、有效。 展开更多
关键词 弱电网 锁相环 谐波线性化 稳定边界 参数自适应
下载PDF
沅水桃源枢纽左岸船闸桥区船模通航条件试验研究 被引量:1
20
作者 蔡创 李林 +2 位作者 李科 王多银 许光祥 《水运工程》 2024年第3期74-81,共8页
沅江大桥通航环境十分复杂,原大桥通航孔布置不合理,严重制约了桃源枢纽二线船闸扩建工程建设。针对桥区通航条件差的问题,对其左岸桥梁通航孔布置方案进行船模试验研究,采用定床河工模型和小尺度船模试验相结合,并从船模试验的舵角、... 沅江大桥通航环境十分复杂,原大桥通航孔布置不合理,严重制约了桃源枢纽二线船闸扩建工程建设。针对桥区通航条件差的问题,对其左岸桥梁通航孔布置方案进行船模试验研究,采用定床河工模型和小尺度船模试验相结合,并从船模试验的舵角、漂角和航速等航行参数进行综合分析,结果表明:在相同通航总净宽的情况下,双孔双向要优于双孔单向;桥梁通航孔右移可降低一线船闸船舶下行过桥难度,但会增加二线船闸船舶上行过桥的难度。建议左岸新建桥梁通航孔净宽应不小于220 m,桥位相比于现状桥梁右移约75 m,采用双孔双向,两线船闸分槽航行的方式。 展开更多
关键词 二线船闸 船模试验 通航条件 桥位
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部