白内障术后角膜后弹力层脱离的临床观察

目的:探讨白内障超声乳化联合人工晶状体植入术及白内障囊外摘除联合人工晶状体植入术所致角膜后弹力层脱离的原因及有效诊疗方法。方法:回顾性分析2015-01/2017-12在我院行白内障超声乳化联合人工晶状体植入术或白内障囊外摘除联合人工晶状体植入术的2006例2069眼,对术中或者术后发生角膜后弹力层脱离的26例26眼患者的诊疗及预后进行临床观察。结果:发生不同程度角膜后弹力层脱离的26例26眼患者经相应治疗,未发生角膜内皮失代偿。角膜水肿消退,恢复透明,视力不同程度地提升。UBM检查证实后弹力层复位。结论:白内障术中术后及时发现,根据不同情况选择合适的治疗方法,是治疗白内障术后角膜后弹力层脱离,恢复患者视力的关键。

玻璃体切除术联合巩膜外环扎治疗脉络膜脱离型视网膜脱离

目的:探讨玻璃体切除联术合巩膜外环扎治疗脉络膜脱离型视网膜脱离的临床疗效。方法:回顾性分析2014-01/2018-02在我院行玻璃体切除术联合巩膜外环扎治疗的脉络膜脱离型视网膜脱离患者19例19眼,术后3~12mo行玻璃体腔硅油取出术。观察患者术后视网膜复位率、眼压、视力恢复及并发症情况。结果:本组患者术后视网膜均复位,术后3mo患眼玻璃体腔硅油填充状态下眼压(16.09±3.58mmHg)、硅油取出术后6mo眼压(14.69±3.10mmHg)均高于术前(6.78±1.90mmHg)(均 P <0.05)。硅油取出术后6mo,15眼患者视力较术前提高。术后无低眼压及眼球萎缩等并发症发生。结论:玻璃体切除术联合巩膜外环扎治疗脉络膜脱离型视网膜脱离是相对安全有效的,视网膜复位率高,术后并发症少,再次手术率低。

可视球囊扩张导管在经皮肾镜取石术中的应用(附20例报告)

目的评价可视球囊扩张在经皮肾镜取石术(PCNL)中的可行性和安全性。方法回顾性分析2017年3月-2018年3月应用可视球囊扩张导管建立通道行PCNL的20例肾结石患者的病例资料。结果 20例均成功应用可视球囊建立皮肾通道,通道建立时间为5.0～13.5 min,平均(7.2±2.1)min,手术时间为30.0～120.0 min,平均(59.1±21.9)min。术后血尿(ClavienⅠ)2例,经保守治疗好转。发热(ClavienⅡ)1例,经抗生素治疗好转。1例残留结石行体外冲击波治疗。术后1个月无石率和手术成功率分别为90.00%和95.00%,术后3个月无石率为100.00%。结论可视球囊有助于提高建立皮肾通道的准确性和提高手术成功率。

Noise Reduction of an Axial Piston Pump by Valve Plate Optimization

Current researches mainly focus on the investigations of the valve plate utilizing pressure relief grooves. However,air?release and cavitation can occur near the grooves. The valve plate utilizing damping holes show excellent perfor?mance in avoiding air?release and cavitation. This study aims to reduce the noise emitted from an axial piston pump using a novel valve plate utilizing damping holes. A dynamic pump model is developed,in which the fluid properties are carefully modeled to capture the phenomena of air release and cavitation. The causes of di erent noise sources are investigated using the model. A comprehensive parametric analysis is conducted to enhance the understanding of the e ects of the valve plate parameters on the noise sources. A multi?objective genetic algorithm optimization method is proposed to optimize the parameters of valve plate. The amplitudes of the swash plate moment and flow rates in the inlet and outlet ports are defined as the objective functions. The pressure overshoot and undershoot in the piston chamber are limited by properly constraining the highest and lowest pressure values. A comparison of the various noise sources between the original and optimized designs over a wide range of pressure levels shows that the noise sources are reduced at high pressures. The results of the sound pressure level measurements show that the optimized valve plate reduces the noise level by 1.6 d B(A) at the rated working condition. The proposed method is e ective in reducing the noise of axial piston pumps and contributes to the development of quieter axial piston machines.

Alignment of beam position monitors in cryomodule of CADS injector Ⅱ

Significant temperature difference(300-77 K or even 4 K) can cause large deformations and displacements of the beam position monitors(BPMs),which affect BPMs measurement resolution or even cause their malfunction in cryogenic situations.In this paper,to check the offset from the mechanical to electrical center in low temperature(77 K),Fourier's law and finite element method are used to simulate cryo-deformation.Laser tracker and micro-alignment telescope are employed in combined BPM calibration,installation and monitoring.The calibration error is<0.02 mm,and the installation and monitoring precision are 0.06 mm and 0.01 mm,respectively.The monitored cryo-deformation agrees well with the simulation results.These indicate that the combined alignment can improve performance of the BPM system.All these guaranteed the success of running the 9.55 MeV@2.14 mA cw protons.

Cryogenic system design for HIAF iLinac

A helium cryogenic system is designed by the Institute of Modern Physics,Chinese Academy of Sciences,to supply different cooling powers to the cryomodules of ion-Linac(iLinac)accelerator,which serves as the injector of the High Intensity Heavy-Ion Accelerator Facility project.The iLinac is a superconducting heavy-ion accelerator approximately 100 m long and contains 13 cryomodules cooled by superfluid helium.This article describes the cryogenic system design of the iLinac accelerator.The requirements of the cryogenic system,such as cooling mode,refrigeration temperature,operating pressure and pressure stability,are introduced and described in detail.In addition,heat loads from different sources are analyzed and calculated quantitatively.An equivalent cooling capacity of 10 kW at 4.5 K was determined for the cryogenic system according to the total heat load.Furthermore,a system process design was conducted and analyzed in detail.Further,the system layout and the main equipment are presented.

Investigation of factors affecting vertical sag of stretched wire

To study vertical sag requirements and factors affecting the stretched wire alignment method,the vertical sag equation is first derived theoretically.Subsequently,the influencing factors(such as the hanging weight or tension,span length,temperature change,elastic deformation,and the Earth’s rotation)of the vertical sag are summarized,and their validity is verified through actual measurements.Finally,the essential factors affecting vertical sag,i.e.,the specific strength and length,are discussed.It is believed that the vertical sag of a stretched wire is proportional to the square of the length and inversely proportional to the specific strength of the material.

使用带孔阻尼套的座阀液动力试验和数值研究（英文）

目的:液压自由活塞发动机性能受燃油喷射系统开关阀性能限制。本文旨在对开关阀内部结构进行优化,降低液动力,从而提高阀的开启速度。创新点:1.提出一种易于安装的带孔阻尼套结构,可以用于改变阀芯表面压力分布和油液射流角,从而降低液动力;2.建立数值仿真模型,分析阻尼套不同结构和安装参数对液动力和空化的影响。方法:1.进行数值模拟,分析阀芯表面压力分布和内部流场分布,并通过实验验证方法有效性和模型准确性;2.对不同阻尼孔宽度、深度和相对位置下的阀芯液动力和流量损失情况进行对比和分析;3.对上述不同阻尼孔结构下阀内空化情况进行仿真和对比;4.建立燃油喷射系统试验台,验证阻尼套对提高阀开启速度的作用。结论:1.提出的带孔阻尼套结构可以有效降低阀芯液动力。2.随阻尼孔的减小,其对液动力的改变作用和节流作用逐渐增强;阻尼孔足够小时液动力反向并逐渐加强。3.阻尼套对油液的阻碍作用也会改变流场内的空化情况,但空化强度不一定随节流孔的变大而单调变强,其还受相对安装位置影响。4.带孔阻尼套可以有效降低阀的开启时间。

Valve-based compensation for controllability improvement of the energy-saving electrohydraulic flow matching system

The energy-saving electrohydraulic flow matching （EFM） system opens up an opportunity to minimize valve losses by fully opening the control valves, but the controllability is lost under overrunning load conditions. To address this issue, this paper proposes a valve-based compensator to improve the controllability of the energy-saving EFM system. The valve-based compensator consists of a static compensator and a differential dynamic compensator based on load conditions. The energy effi- ciency, the stability performance, and the damping characteristic are analyzed under different control parameters. A parameter selection method is used to improve the efficiency, ensure the stability performance, and obtain good dynamic behavior. A test rig with a 2-t hydraulic excavator is built, and experimental tests are carried out to validate the proposed valve-based compensator. The experimental results indicate that the controllability of the EFM system is improved, and the characteristic of high energy efficiency is obtained by the proposed compensator.

转位角对串联式轴向柱塞泵流量脉动的影响（英文）

目的:探索转位角对串联泵出口流量脉动的影响,揭示转位角对流量脉动的影响机理,获得最佳转位角以减小流量脉动,以及探索转位角对工况的敏感性。方法:1.建立基于单柱塞腔模型的单柱塞泵模型,求解其出口流量脉动特性;2.研究不同转位角下串联泵的出口流量脉动,优选转位角;3.对比不同转位角下出口流量脉动对工况的敏感性。结论:1.对于单个转子使用九柱塞的串联式轴向柱塞泵,最佳转位角是20°,因该角度可消除流量脉动在奇数阶次下的幅值;2.在大范围工况下,转位角为20°时可减小约50%的流量脉动。

壳体压力对轴向柱塞泵滑靴副特性的影响（英文）

目的:旨在探索壳体压力对滑靴副特性的影响,期望给出特定泵结构和工况下极限壳体压力的确定准则,提高滑靴运行的可靠性。创新点:1.基于滑靴平衡方程,推导出滑靴支撑力等效半径与工况之间的关系;2.得出离散油膜刚度计算公式;3.给出评价准则,确定极限壳体压力。方法:1.基于滑靴副油膜模型分析不同进口压力和壳体压力对滑靴副油膜厚度、滑靴倾覆角度、油膜刚度和动压支撑力等效作用半径的影响;2.以动压支撑力等效作用半径小于滑靴外径为评价标准确定泵极限壳体压力。结论:1.给定泵结构和工况条件下,油膜厚度和滑靴倾覆角度随着壳体压力的增大而增大;2.壳体压力增大,高低压过渡区支撑刚度降低,等效动压支撑力作用点向滑靴外缘移动;3.基于油膜模型提出的壳体压力确定准则可以有效的确定极限壳体压力。

宽幅排量工况下轴向柱塞泵容积损失及效率变化特征（英文）

目的：宽幅排量工况下高效率性能对于作为变排量泵控节能系统动力源的柱塞泵至关重要，而现有研究对宽幅排量工况下泵效率及各容积损失变化特征的认识尚为不足。本研究探索并阐明泵效率、容积损失（泄漏损失及压缩流量损失）及各损失所占比重随排量工况的变化特征。创新点：1．提出更完整的滑靴副泄漏计算方程，建立显式容积损失仿真模型，发现由滑靴挤压微运动造成的挤压泄漏的不可忽略性；2．揭示泵压缩流量、泄漏流量及其造成的能量损失随排量工况的变化特征。方法：1．基于纳维一斯托克斯方程及流体连续性方程，推导出更完整的滑靴副泄漏计算方程，基于此方程建立显式容积损失仿真模型；2．在不同压力、转速及排量工况组合下对泵各损失进行224组大范围工况下的大量实验测试；3．基于仿真结果及实验结果对宽幅排量工况下泵效率及各容积损失变化特征进行分析讨论。结论：1．泵总效率随排量减小显著下降；2．在额定转速T况下，5～35MPa压力等级及13％～100％满排量变化范围内，泵容积损失在泵总损失中所占比重在13％--47％幅度内变化；3．额定转速下泵压缩流量损失在总容积损失中所占比重在30MPa压力及88％满排量等级以上时最高可达41％，此后随着排量减小而逐渐减小，当排量降至低于38％满排量或压力降至低于5MPa时，压缩流量损失在泵总容积损失中占比低于20％；4．压缩流量随排量减小而减小，而在绝大部分工况下，泵泄漏流量的典型变化特征是随着排量减小而逐渐增大，或先随着排量减小而减小，但在当减小到某一‘极小值时随着排量进一步的减小而逐渐增大；5．由滑靴挤压微运动造成的滑靴副挤压泄漏可以达到与由压差效应造成的滑靴副压差泄漏相当的数量级。

Lessons Learned from a Case with Valgus Deformity of the Knee Following Partial Removal of Lateral Discoid Meniscus

Few studies have focused on the possible change in the axial alignment of the lower limb after lateral meniscectomy. Here, we present a patient with valgus deformity of the knee following the partial removal of lateral discoid meniscus. With the distal femur osteotomy and fixation, this complication was treated successfully. This case suggested that we should pay more attention to the axial alignment of the lower limb in patients with torn discoid lateral meniscus before meniscectomy, as a severe valgus inclination may develop in some of these patients.

Endoscopic Combined Intrarenal Surgery for the Treatment of Postpercutaneous Nephrolithotomy Residual Stones

Endourological treatment modalities for kidney stones include extracorporeal shock wave lithotripsy （ESWL）, flexible ureteroscopy （fURS）, percutaneous nephrolithotomy （PCNL）, and laparoscopy.PCNL is currently the recommended treatment for patients with complex renal stones. However, for complex renal stones, the residual stone after PCNL is very common, and the treatment is a sticky business.

Surgical interventions for symptomatic urinary stones during pregnancy

To the Editor:Symptomatic urinary stone events have been reported to impact between 1/200 and 1/2000 pregnancies worldwide.Conservative treatment is the first line of treatment for uncomplicated cases.[1]About one-third of cases ultimately require active management such as ureteral stent insertion(USI),nephrostomy,and definitive stone treatment.

A design constraint for a double-acting telescopic hydraulic cylinder in a hydraulic erecting system

Hydraulic erecting systems are widely used in missile and rocket launchers because of their high power density.The double-acting telescopic hydraulic cylinder(DATHC)plays a decisive role in the safe and proper operation of such systems.In particular,improper design of effective areas of a DATHC could potentially lead to an overspeed descent with severe damage for the erecting system.Unfortunately,there is no design constraint for DATHC to prevent this.Therefore,in this paper,a simplified and practical design constraint is proposed.Based on a developed mathematical model of a typical erecting system,we simulated and analyzed not only six cases meeting and not meeting the design constraint,but also the effectiveness of the design constraint under different loads.Experiments were then carried out under four cases.Simulation and experimental results validate the simplified design constraint,a constraint inequation guiding the design of diameters of effective areas for a DATHC.

Practice of flow control and smart valves

Introduction The usual metaphors of“heart”and“throat”indi-cate the importance of pumps and valves in industrial systems including petroleum,chemical,metallurgy,aviation,and aerospace.With the continuous penetra-tion of the industrial internet,the miniaturization,digi-tization,multi-functionalization,and systemization of valves have become very important(Si et al.,2020;Chang et al.,2021;Pang et al.,2021;Bonilla et al.,2022;Yuan et al.,2022;Zhao et al.,2022).