Shape and diffusion instabilities of two non-spherical gas bubbles under ultrasonic conditions

Ultrasonic cavitation involves dynamic oscillation processes induced by small bubbles in a liquid under the influence of ultrasonic waves. This study focuses on the investigation of shape and diffusion instabilities of two bubbles formed during cavitation. The derived equations for two non-spherical gas bubbles, based on perturbation theory and the Bernoulli equation, enable the analysis of their shape instability. Numerical simulations, utilizing the modified Keller–Miksis equation,are performed to examine the shape and diffusion instabilities. Three types of shape instabilities, namely, Rayleigh–Taylor,Rebound, and parametric instabilities, are observed. The results highlight the influence of initial radius, distance, and perturbation parameter on the shape and diffusion instabilities, as evidenced by the R_0–P_a phase diagram and the variation pattern of the equilibrium curve. This research contributes to the understanding of multiple bubble instability characteristics, which has important theoretical implications for future research in the field. Specifically, it underscores the significance of initial bubble parameters, driving pressure, and relative gas concentration in determining the shape and diffusive equilibrium instabilities of non-spherical bubbles.

腕关节镜辅助Wristore外固定架治疗Barton骨折患者的效果

目的探讨腕关节镜辅助Wristore外固定架治疗Barton骨折患者的效果。方法选取2019年12月至2022年12月聊城市第三人民医院收治的100例Barton骨折患者进行随机对照试验,采用随机数字表法将其分为对照组和观察组,各50例。对照组男26例,女24例,年龄(40.26±3.58)岁;观察组男22例,女28例,年龄(43.55±2.44)岁。对照组采用常规治疗方法,观察组在常规治疗基础上采用腕关节镜辅助Wristore外固定架进行治疗。比较两组Gartland-Werley腕关节功能评分、疼痛视觉模拟量表(Visual Analogue Scale,VAS)评分、关节活动度及并发症发生率。统计学方法采用t检验、χ^(2)检验。结果治疗后,观察组Gartland-Werley腕关节功能评分(5.29±0.61)分,显著低于对照组的(12.42±2.90)分,差异有统计学意义(t=17.013,P<0.05)。观察组术后1周、1个月VAS评分均低于对照组[(3.24±1.16)分比(6.88±1.33)分、(1.45±0.94)分比(4.63±1.11)分],差异均有统计学意义(t=14.585、15.459,均P<0.05)。观察组关节活动度优于对照组[82%(41/50)比42%(21/50)],差异有统计学意义(χ^(2)=16.978,P<0.05)。观察组并发症发生率低于对照组[12%(6/50)比48%(24/50)],差异有统计学意义(χ^(2)=15.429,P<0.05)。结论腕关节镜辅助Wristore外固定架治疗Barton骨折患者效果良好,可以显著改善患者腕关节功能,降低疼痛程度,提高关节活动度,减少并发症的发生,值得在临床上广泛应用。

Mechanism study of producing non-spherical powder in gas atomization

Gas atomization was usually regarded as a good method for producing the spherical or approximate spherical powders. We found a lot of non-spherical powders in production processes, especially in larger particle size distribution area. The causes of producing non-spherical powders are explained and some analyses are done in order to find a better condition of producing spherical powders in this paper. The following morphologies were obtained by atomized Fe50 Co50 and pure iron and investigated by scanning electron microscopy （SEM）.

Preparation of Non-spherical Colloidal Silica Nanoparticle and Its Application on Chemical Mechanical Polishing of Sapphire

Non-spherical colloidal silica nanoparticle was prepared by a simple new method, and its particle size distribution and shape morphology were characterized by dynamic light scattering(DLS) and the Focus Ion Beam(FIB) system. This kind of novel colloidal silica particles can be well used in chemical mechanical polishing(CMP) of sapphire wafer surface. And the polishing test proves that non-spherical colloidal silica slurry shows much higher material removal rate(MRR) with higher coefficient of friction(COF) when compared to traditional large spherical colloidal silica slurry with particle size 80 nm by DLS. Besides, sapphire wafer polished by non-spherical abrasive also has a good surface roughness of 0.460 6 nm. Therefore, non-spherical colloidal silica has shown great potential in the CMP field because of its higher MRR and better surface roughness.

Distribution of non-spherical nanoparticles in turbulent flow of ventilation chamber considering fluctuating particle number density

The Reynolds-averaged general dynamic equation(RAGDE)for the nanoparticle size distribution function is derived,including the contribution to particle coagulation resulting from the fluctuating concentration.The equation together with that of a turbulent gas flow is solved numerically in the turbulent flow of a ventilation chamber with a jet on the wall based on the proposed model relating the fluctuating coagulation to the gradient of mean concentration.Some results are compared with the experimental data.The results show that the proposed model relating the fluctuating coagulation to the gradient of mean concentration is reasonable,and it is necessary to consider the contribution to coagulation resulting from the fluctuating concentration in such a flow.The changes of the particle number concentration M_(0) and the geometric mean diameter dg are more obvious in the core area of the jet,but less obvious in other areas.With the increase in the initial particle number concentration m00,the values of M_(0) and the standard deviation of the particle sizeσdecrease,but the value of d_(g) increases.The decrease in the initial particle diameter leads to the reduction of M_(0) andσand the increase in d_(g).With the increase in the Reynolds number,particles have few chances of collision,and hence the coagulation rate is reduced,leading to the increase in M_(0) andσand the decrease in d_(g).

Simulation on hydrodynamics of non-spherical particulate system using a drag coefficient correlation based on artificial neural network

Fluidization of non-spherical particles is very common in petroleum engineering.Understanding the complex phenomenon of non-spherical particle flow is of great significance.In this paper,coupled with two-fluid model,the drag coefficient correlation based on artificial neural network was applied in the simulations of a bubbling fluidized bed filled with non-spherical particles.The simulation results were compared with the experimental data from the literature.Good agreement between the experimental data and the simulation results reveals that the modified drag model can accurately capture the interaction between the gas phase and solid phase.Then,several cases of different particles,including tetrahedron,cube,and sphere,together with the nylon beads used in the model validation,were employed in the simulations to study the effect of particle shape on the flow behaviors in the bubbling fluidized bed.Particle shape affects the hydrodynamics of non-spherical particles mainly on microscale.This work can be a basis and reference for the utilization of artificial neural network in the investigation of drag coefficient correlation in the dense gas-solid two-phase flow.Moreover,the proposed drag coefficient correlation provides one more option when investigating the hydrodynamics of non-spherical particles in the gas-solid fluidized bed.

NUMERICAL SIMULATIONS OF POLARIZED SCATTERING FROM RANDOM CLUSTERS OF SPATIALLY-ORENTED, NON-SPHERICAL SCATTERS

Employing multiple scattering formulation of T-matrix method, numerical simulations are developed and applied to polarized scattering from random clusters of spatially-oriented, non-spherical particles. Polarized scattering is numerically presented for the functional dependence on particle shape, size, spatial distribution and orientation, and other physical parameters. Numerical calculations of backscattering from randomly clustered particles are well compared with that from independent particles and clusters. It can be seen that spatial distribution and orientation of non-spherical particles can have significant effect on scattering.

Non-spherical particle mixing behaviors by spherical inert particles assisted in a fluidized bed

Fluidized beds are widely used in many industrial fields such as petroleum,chemical and energy.In actual industrial processes,spherical inert particles are typically added to the fluidized bed to promote fluidization of non-spherical particles.Understanding mixing behaviors of binary mixtures in a fluidized bed has specific significance for the design and optimization of related industrial processes.In this study,the computational fluid dynamic-discrete element method with the consideration of rolling friction was applied to evaluate the mixing behaviors of binary mixtures comprising spherocylindrical particles and spherical particles in a fluidized bed.The simulation results indicate that the differences between rotational particle velocities were higher than those of translational particle velocities for spherical and non-spherical particles when well mixed.Moreover,as the volume fraction of the spherocylindrical particles increases,translational and rotational granular temperatures gradually increase.In addition,the addition of the spherical particles makes the spherocylindrical particles preferably distributed in a vertical orientation.

A CFD-DEM-Wear Coupling Method for Stone Chip Resistance of Automotive Coatings with a Rigid Connection ParticleMethod for Non-Spherical Particles

The stone chip resistance performance of automotive coatings has attracted increasing attention in academic and industrial communities.Even though traditional gravelometer tests can be used to evaluate stone chip resistance of automotive coatings,such experiment-based methods suffer from poor repeatability and high cost.The main purpose of this work is to develop a CFD-DEM-wear coupling method to accurately and efficiently simulate stone chipbehaviorof automotive coatings inagravelometer test.Toachieve this end,an approach coupling an unresolved computational fluid dynamics(CFD)method and a discrete element method(DEM)are employed to account for interactions between fluids and large particles.In order to accurately describe large particles,a rigid connection particle method is proposed.In doing so,each actual non-spherical particle can be approximately described by rigidly connecting a group of non-overlapping spheres,and particle-fluid interactions are simulated based on each component sphere.An erosion wear model is used to calculate the impact damage of coatings based on particlecoating interactions.Single spherical particle tests are performed to demonstrate the feasibility of the proposed rigid connection particle method under various air pressure conditions.Then,the developed CFD-DEM-wear model is applied to reproduce the stone chip behavior of two standard tests,i.e.,DIN 55996-1 and SAE-J400-2002 tests.Numerical results are found to be in good agreement with experimental data,which demonstrates the capacity of our developed method in stone chip resistance evaluation.Finally,parametric studies are conducted to numerically investigate the influences of initial velocity and test panel orientation on impact damage of automotive coatings.

Application of a Neural Network to Store and Compute the Optical Properties of Non-Spherical Particles

Radiative transfer simulations and remote sensing studies fundamentally require accurate and efficient computation of the optical properties of non-spherical particles.This paper proposes a deep learning(DL)scheme in conjunction with an optical property database to achieve this goal.Deep neural network(DNN)architectures were obtained from a dataset of the optical properties of super-spheroids with extensive shape parameters,size parameters,and refractive indices.The dataset was computed through the invariant imbedding T-matrix method.Four separate DNN architectures were created to compute the extinction efficiency factor,single-scattering albedo,asymmetry factor,and phase matrix.The criterion for designing these neural networks was the achievement of the highest prediction accuracy with minimal DNN parameters.The numerical results demonstrate that the determination coefficients are greater than 0.999 between the prediction values from the neural networks and the truth values from the database,which indicates that the DNN can reproduce the optical properties in the dataset with high accuracy.In addition,the DNN model can robustly predict the optical properties of particles with high accuracy for shape parameters or refractive indices that are unavailable in the database.Importantly,the ratio of the database size(~127 GB)to that of the DNN parameters(~20 MB)is approximately 6810,implying that the DNN model can be treated as a highly compressed database that can be used as an alternative to the original database for real-time computing of the optical properties of non-spherical particles in radiative transfer and atmospheric models.

Multi-Segmental Osteocutaneous Free Fibula Flap for Three-Dimensional Post-Traumatic Thumb and Wrist Reconstruction

Thumb reconstruction following a traumatic injury challenge depends on the extent of the injury. Ideally, reconstruction should restore thumb length and position and retain thumb stability, mobility, and strength, while preserving sensation and aesthetics. Achieving these outcomes can be especially challenging in severe cases of soft tissue and bony loss. The authors present a case of a 20-year-old right-hand dominant female involved in a motor vehicle accident who sustained severe crush injuries and burns to her right hand. Her injuries included soft tissue and bony defects extending from the thumb to the distal radius, namely avulsion of the thumb and significant loss of the distal radial and carpal column, resulting in severe wrist instability. We employed a three-segment vascularized osteocutaneous fibula flap to reconstruct the thumb and wrist to restore bony construct, carpal support, and soft tissue coverage. Thumb motion could not be achieved, but this technique offered a sensate, functional post for opposition and the appearance of an anatomic hand. Because of this surgery, the patient was enabled to graduate from college and pursue full-time employment. The authors hope that this report will add to the fund of knowledge and surgeon armamentarium for similar devastating injuries demanding thumb and wrist reconstruction.

全腕关节置换术后腕关节生物力学研究进展

1人工腕关节发展概述第1代人工腕关节Swanson是由德国医生Gluck采用象牙和硅胶制作成的铰链式假体,其设计不符合腕关节生物力学机制,且硅胶容易老化、破损[1~4]。继而出现第2代假体,包括Volz假体和Meuli假体,为非铰链式[5,6],假体远、近端柄状物以髓内插销的方式嵌插于掌骨与桡骨髓腔中,近端假体与桡骨形成关节窝,远端假体的弧面与近端关节窝形成关节,可进行屈伸与轻微尺桡偏活动[7]。

子午流注腕踝针疗法防治化疗所致恶心呕吐的效果研究

目的探讨子午流注腕踝针疗法防治化疗所致恶心呕吐的临床效果。方法选取接受静脉化疗的肿瘤患者212例住院患者随机分为观察组107例、对照组105例。对照组采用常规护理方法,观察组在对照组的基础上给予腕踝针干预治疗。观察化疗后所致恶心呕吐发生率、严重程度、焦虑抑郁、日常生活能力。结果观察组患者化疗后第6天恶心呕吐发生率、严重程度、焦虑抑郁低于对照组(P<0.01),观察组患者化疗后第6天日常生活能力高于对照组(P<0.01)。结论子午流注腕踝针疗法可有效降低化疗所致肿瘤患者恶心呕吐发生率及严重程度,缓解焦虑情绪,提高生存质量具有较好的临床效果。

一种5R+异形3RPS的混联上肢康复机构研究

为解决现有上肢康复外骨骼结构复杂以及腕部康复效果不佳的问题,提出了一种5R+异形3-RPS的混联上肢康复外骨骼机构,可以实现7个自由度的上肢康复训练。建立康复外骨骼的整体运动学模型,将串联部分与并联部分结合,计算串联部分的位姿转换、腕部并联机构的位姿变换矩阵及整体机构的运动学反解。使用ADAMS软件对该康复机构进行运动学仿真分析,通过末端质心的位移、速度和加速度曲线的分析,证明了机构可以按照康复轨迹正确进行并且过渡安全稳定。通过10次重复实物模型试验,验证腕部所能达到的角度范围及运行的平稳性。腕部装置实际的活动角度范围可达到理想状态的(73~82)%,运行符合预期运动轨迹,验证了理论推导和结构设计的正确性和合理性。

阶段性康复训练在桡骨远端骨折术后康复中的应用

目的探析阶段性康复训练在桡骨远端骨折术后康复中的应用效果。方法随机选取2018年1月—2022年12月常州市武进人民医院收治的80例桡骨远端骨折手术患者为研究对象,以随机数表法分为观察组(n=40,采用阶段性康复训练)和对照组(n=40,采用常规康复训练)。比较两组训练后Cooney腕关节功能、训练前后腕关节活动度以及术后手术处肿胀、疼痛消失时间等指标。结果观察组训练后腕关节功能恢复有效率为97.50%,高于对照组的80.00%,差异有统计学意义(χ^(2)=4.507,P<0.05)。观察组训练后患肢各项腕关节活动度相关指标均高于训前及对照组训练后,差异有统计学意义(P均<0.05)。观察组患肢肿胀及疼痛消失时间均短于对照组,差异有统计学意义(P均<0.05)。结论阶段性康复训练能更好地促进桡骨远端骨折术后腕关节功能及活动度的恢复,缩短肿胀消失时间和疼痛消失时间。

新型导向器用于经皮螺钉固定治疗舟状骨骨折

背景:舟状骨骨折是临床上常见的腕部骨折,主要采用经皮螺钉治疗,首先闭合复位骨折端,然后将空心加压螺钉精准置于舟状骨轴心并加压固定骨折端,能够促进骨折愈合,使腕关节获得良好功能。目的:评价一种新型克氏针导向器辅助经皮空心加压螺钉治疗舟状骨骨折的临床疗效。方法:回顾性分析2015年1月至2020年12月河北医科大学第三医院手外科收治的15例舟状骨骨折患者的临床资料。所有患者均采用新型导向器辅助经皮空心加压螺钉固定治疗。统计患者的骨折愈合时间、手术时间、透视次数、重返工作的时间及并发症。术后12个月采用改良Mayo腕关节评分对腕关节功能进行评估,测量患侧及健侧腕关节掌屈、背伸、尺偏、桡偏活动度及握力。结果与结论:所有患者均完成了12个月随访。术后X射线片示:空心压力螺钉位于舟状骨轴心位置。所有舟状骨骨折均获骨性愈合,平均愈合时间10.0周。手术平均历时55.7 min,术中平均透视次数10.9次,平均10.3周重返工作岗位。腕关节功能:优9例,良5例,可1例,优良率93.3%。患侧及健侧的腕关节掌屈、背伸、尺偏、桡偏活动度及握力相比较,差异无显著性意义(P>0.05)。所有患者均未发生伤口感染、骨折畸形愈合、螺钉松动及断裂等并发症。结果表明,应用新型导向器可以缩短手术时间,减少术中透视次数,提高螺钉精准度,缩短重返工作时间,腕关节功能恢复良好。该导向器使空心加压螺钉治疗舟状骨骨折手术更容易。

基于文献计量分析皮内针疗法适宜病症与临床应用进展

目的基于文献计量分析皮内针疗法的临床文献,探讨皮内针疗法的适宜病症与临床应用进展。方法通过计算机检索中国知网(CNKI)、万方数据库(Wanfang data)和维普中文期刊数据库中与皮内针疗法相关的临床研究文献,应用文献计量学的方法对皮内针疗法发文量、病谱和适宜病症进行分析。结果临床涉及论文共2220篇,近10年发文量显著增长。皮内针疗法临床涉及病症208种。一级适宜病症为手术后疼痛、失眠症、偏瘫、面神经麻痹;二级适宜病症为肩痛、颈椎病、癌痛、膝骨关节炎、腰椎间盘移位、便秘、头痛;三级适宜病症为带状疱疹、遗尿、放化疗后不良反应、变应性鼻炎、呃逆、面肌痉挛;四级适宜病症包括痛经、高血压、糖尿病、胃肠功能紊乱、痹证、吞咽障碍、腰扭伤、肥胖症。结论皮内针疗法是近年来的临床研究热点,其治疗疾病以痛症居多,其次为各类慢性病。不同针具中,揿针的应用受到广泛关注。

腕踝针联合商调音乐在混合痔术后病人中的应用

目的:探讨腕踝针联合商调音乐对混合痔术后疼痛和相关并发症发生情况的影响。方法:选择2021年11月—2022年7月在我院肛肠科诊断为湿热下注型混合痔拟行混合痔外剥内扎术的114例病人,随机分为对照组、干预1组及干预2组各38例。对照组进行常规镇痛和中药换药、熏洗等常规护理;干预1组在对照组基础上给予腕踝针治疗法;干预2组在对照组基础上给予腕踝针与商调音乐疗法的联合治疗。于术后第3天、术后第5天采用视觉模拟疼痛评分(VAS)、Wexner便秘评分、便后出血评分、肛缘水肿评分评估病人的肛门疼痛、便秘、便后出血、肛缘水肿并发症发生情况。结果:与对照组相比,干预1组及干预2组的术后VAS评分明显降低(P<0.05),首次排尿用时和尿流状况等排尿功能评分、Wexner便秘评分、术后便时出血评分及肛缘水肿评分明显降低(P<0.05),且干预2组术日、术后第3天、术后第5天VAS评分的改善优于干预1组(P<0.05),术后首次排尿时长、小腹状况评分及术后第3天Wexner便秘评分的改善优于干预1组(P<0.05)。结论:腕踝针联合商调音乐应用于混合痔术后病人,可减轻病人疼痛,改善术后便秘、便血、肛缘水肿等并发症,提高排尿功能。

远端尺桡关节融合结合尺骨远端假关节成形术治疗远端尺桡关节炎

目的探讨关节镜下远端尺桡关节融合结合尺骨远端假关节成形术(改良Sauvé-Kapandji术)治疗远端尺桡关节炎的临床疗效。方法采用关节镜下改良Sauvé-Kapandji术治疗12例远端尺桡关节炎患者。记录远端尺桡关节融合情况、并发症发生情况、腕关节疼痛VAS评分及患侧握力,测量关节活动度,采用Mayo评分评价腕关节功能。结果患者均获得随访,时间8~36个月。远端尺桡关节均融合,时间11~28(18.0±6.3)周。无截骨断端再骨化、骨桥形成等情况发生。术后6个月,疼痛VAS评分较术前降低(P<0.05),腕关节活动度和前臂旋转度较术前改善(P<0.05),患侧握力较术前改善(P<0.05)。术后6个月腕关节功能Mayo评分为55~95(76.3±14.7)分,其中优6例,良3例,中2例,差1例,优良率9/12。结论采用关节镜下改良Sauvé-Kapandji术治疗远端尺桡关节炎融合率高,疼痛缓解明显,关节功能恢复较好。

腕踝针联合药物罐治疗寒湿痹阻型肩周炎临床观察

目的观察腕踝针联合药物罐治疗寒湿痹阻型肩周炎的临床效果。方法将80例寒湿痹阻型肩周炎患者随机分为A组、B组、C组和D组,每组20例。A组采用口服双氯芬酸钠缓释片治疗,B组、C组和D组在A组基础上分别采用腕踝针、药物罐及腕踝针联合药物罐治疗。观察各组治疗前后视觉模拟量表(VAS)评分、肩关节功能Mallet评分的变化情况,以及各组临床效果。结果各组治疗后1 d、7 d、14 d、21 d的VAS及肩关节功能Mallet评分与治疗前比较,差异均有统计学意义(P<0.05);治疗后1 d、7 d、14 d、21 d,B组、C组和D组VAS及肩关节功能Mallet评分与A组比较,差异均有统计学意义(P<0.05),D组VAS及Mallet评分与B组和C组比较,差异均有统计学意义(P<0.05)。结论腕踝针联合药物罐治疗寒湿痹阻型肩周炎效果确切,能有效改善患者肩关节疼痛及活动受限的症状。