A novel dual-channel thermo-optic locking method for the whispering gallery mode microresonator

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.

Early Treatment Outcome of Humeral Shaft Fracture Non-Union in Adults: Comparative Study of Plating versus Interlocking Nailing

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 3rd 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.

Locking plates for distal fibula fractures in young and elderly patients:A retrospective study

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.

Perspectives of spin-valley locking devices

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.

An injection-locking diode laser at 671 nm with a wide tuning range up to 6 GHz

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.

Knee locking caused by osteochondroma of the proximal tibia adjacent to the pes anserinus:A case report

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.

Triggering,clicking,locking and crepitus of the finger:A comprehensive overview

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.

On the generation of high-quality Nyquist pulses in mode-locked fiber lasers

Nyquist pulses have wide applications in many areas,from electronics to optics.Mode-locked lasers are ideal platforms to generate such pulses.However,how to generate high-quality Nyquist pulses in mode-locked lasers remains elusive.We address this problem by managing different physical effects in mode-locked fiber lasers through extensive numerical simulations.We find that net dispersion,linear loss,gain and filter shaping can affect the quality of Nyquist pulses significantly.We also demonstrate that Nyquist pulses experience similariton shaping due to the nonlinear attractor effect in the gain medium.Our work may contribute to the design of Nyquist pulse sources and enrich the understanding of pulse shaping dynamics in mode-locked lasers.

Phase-locked single-mode terahertz quantum cascade lasers array

We demonstrated a scheme of phase-locked terahertz quantum cascade lasers(THz QCLs)array,with a single-mode pulse power of 108 mW at 13 K.The device utilizes a Talbot cavity to achieve phase locking among five ridge lasers with first-order buried distributed feedback(DFB)grating,resulting in nearly five times amplification of the single-mode power.Due to the optimum length of Talbot cavity depends on wavelength,the combination of Talbot cavity with the DFB grating leads to better power amplification than the combination with multimode Fabry-Perot(F-P)cavities.The Talbot cavity facet reflects light back to the ridge array direction and achieves self-imaging in the array,enabling phase-locked operation of ridges.We set the spacing between adjacent elements to be 220μm,much larger than the free-space wavelength,ensuring the operation of the fundamental supermode throughout the laser's dynamic range and obtaining a high-brightness far-field distribution.This scheme provides a new approach for enhancing the single-mode power of THz QCLs.

Fixation of Calcaneal Tuberosity Beavis II Fracture in Elderly Patients Using Locking Plate Combined with Tension Screw

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.

克服“Locking”发散性的有限元研究进展

从克服Ｌｏｃｋｉｎｇ发散性到高性能格式的研究发展是过去十年有限元法研究的一个重要方面．本文认为所谓高性能有限元方法是一种特别的低阶位移格式，它具有如下的理论和计算优点：（１）保持物理力学问题固有的数学物理特征；（２）因此，应用于工程数值模拟，它是“鲁棒”的、高效的．按此立场，评论介绍了在计算结构力学和计算流体力学中发展的克服两类Ｌｏｃｋｉｎｇ发散性的有限元方法．

一个二阶收敛的平面弹性问题Locking-free三角形元

对于纯位移平面弹性问题,以往构造的单元的能量模误差多是一阶收敛的,本文在不完全三次多项式空间中,基于divv∈P1的限制构造了一个14自由度的非协调三角形单元,该单元是Locking-free的,且能量模和L2―模误差分别达到了二阶和三阶收敛,并且通过数值实验验证了该单元的理论结果。

平面弹性的一个新的Locking-free非协调有限元

针对平面弹性问题构造了一个Locking-free的矩形非协调有限元,并证明该有限元格式关于λ有一致最优收敛阶,其离散误差的能量模为O(h2),L2模为O(h3).最后给出了数值实验对理论结果进行了验证.

线弹性问题的locking-free双参数元(英文)

文中运用双参数法提出了一个4参数的四边形非协调有限元,讨论了该单元对纯位移边界条件下的均匀介质线弹性方程的逼近问题.证明了在材料几乎不可压时单元对弹性问题的一致最优收敛性,数值试验验证了理论分析结果.并通过构造后处理算子,得到了超收敛结果.所有的分析结果都可以推广到三维情形.

弹性力学问题Locking-free有限元离散系统的两水平方法

高次协调元能有效克服弹性力学问题的闭锁(Locking)现象,称这种单元为无闭锁(Locking-free)有限元,但它与线性元相比,往往需要更多的计算机存储单元,具有更高的计算复杂性。针对弹性力学问题Locking-free(四次)有限元离散系统的求解,本文通过分析四次有限元与二次有限元空间之间的关系,并利用有限元基函数的特殊性质,如紧支集性,建立一种以二次有限元(P2)为粗水平空间的两水平方法;然后,利用减缩积分方案,以P2/P0元作为四次元空间的粗水平空间,并结合有效的磨光算子,为Locking-free有限元离散系统设计具有更好计算效率和鲁棒性的求解方法。数值实验结果验证了算法的有效性。

一个应力边界条件下平面弹性问题的Locking-Free有限元方法

用非协调有限元方法解决应力边界条件下平面弹性问题的Locking现象,构造了一个新的四边形单元克服Locking现象,给出了新的非协调有限元格式,证明了此格式的收敛性,并给出了最优的误差估计.

Reissner-Mindlin板模型的Locking-free有限元(英文)

利用Reissner－Mindlin板问题的组合杂交有限元方法，提出了一类Locking－free有限元.

Volar locking distal radius plates show better short-term results than other treatment options: A prospective randomised controlled trial

AIM To compare the outcomes of displaced distal radius fractures treated with volar locking plates and with immediate postoperative mobilisation with the outcomes of these fractures treated with modalities that necessitate 6 wk wrist immobilisation.METHODS A prospective, randomised controlled single-centre trial was conducted with 56 patients who had a displaced radius fracture were randomised to treatment either with a volar locking plate(n = 29), or another treatment modality(n = 27; cast immobilisation with or without wires or external fixator). Outcomes were measured at 12 wk. Functional outcome scores measured were the Patient-Rated Wrist Evaluation(PRWE) Score; Disabilities of the Arm, Shoulder and Hand and activities of daily living(ADLs). Clinical outcomes were wrist range of motion and grip strength. Radiographic parameters were volar inclination and ulnar variance.RESULTS Patients in the volar locking plate group had significantly better PRWE scores, ADL scores, grip strength and range of extension at three months compared with the control group. All radiological parameters were significantly better in the volar locking plate group at 3 mo. CONCLUSION The present study suggests that volar locking plates produced significantly better functional and clinical outcomes at 3 mo compared with other treatment modalities. Anatomical reduction was significantly more likely to be preserved in the plating group. Level of evidence: Ⅱ.

Structure Analysis of Locking Mechanism of Gear-Rack Typed Ship-Lift

Contact nonlinear theory was researched. Contact problem was transformed into optimization problem containing Lagrange multiplier, and unsymmetrical stiffness matrix was transformed into symmetrical stiffness matrix. A finite element analysis （FEA） model defining more than 300 contact pairs for long nut-short screw locking mechanism of a large-scale vertical gear-rack typed ship-lift was built. Using augmented Lagrange method and symmetry algorithm of contact element stiffness, the FEA model was analyzed, and the contact stress of contact interfaces and the von Mises stress of key parts were obtained. The results show that the design of the locking mechanism meets the requirement of engineering, and this method is effective for solving large stole nonlinear contact pairs.

Four corner fusion using a multidirectional angular stable locking plate

AIM: To review the results of our experience with the Medartis Aptus plating system for four corner arthrodesis of the wrist, which uses a combination of compression screws and variable angle locking screws.METHODS: We reviewed the results of 17 procedures in 16 patients that underwent scaphoid excision and four corner fusion using the Medartis Aptus system between May 2010 and June 2014. The primary outcome measure was radiographic and clinical union. RESULTS: The mean clinical follow up time was 20.6 mo. The mean union time was 6 mo. Two non-unions required revision procedures. The mean disabilities of the arm, shoulder and hand score taken after union was 36. The mean final grip strength was 27 kg. The mean final range of movement was 30° flexion and 31° of extension. All patients had a restored scapholunate angle on postoperative radiographs. There were no incidences of dorsal impingement.CONCLUSION: Overall our experience with the Aptus plating system shows comparable results to other methods of fixation for four corner fusion, in the short to medium term.