改良腭咽成形术加舌根Repose手术的围手术期处理

目的探讨改良术式治疗多平面阻塞性睡眠呼吸暂停综合征(OSAHS)的围手术期的注意事项。方法应用低温等离子消融手术系统行改良腭咽成形术并Ⅱ期在鼻内镜电视系统直视下行舌根Repose手术治疗OSAHS患者10例。结果所有病例术后均随访观察12个月以上,并复查睡眠监测。其中显效7例,有效3例,无效0例,总有效率为100%。结论 OSAHS患者围手术期危险性高,手术适应证选择应严格把握,围手术期处理得当可以降低手术风险,同时可避免严重并发症的发生。

腭咽成形联合Repose系统舌根牵引术治疗阻塞性睡眠呼吸暂停低通气综合征患者的围术期护理

目的探讨腭咽成形术联合Repose系统舌根牵引术的围术期护理方法,以减少并发症的发生,提高手术治疗的成功率。方法对26例阻塞性睡眠呼吸暂停低通气综合征(obstructive sleep apnea hypopnea syndrome,OSAHS)患者采用腭咽成形联合Repose系统舌根牵引术治疗。结果所有患者均手术顺利,医护人员术中配合默契,患者症状改善显著。患者术后均出现不同程度的吞咽疼痛、吞咽和讲话困难、进流质反流入鼻腔等情况,于1～2周内上述症状消失,无后遗症。结论腭咽成形联合Repose系统舌根牵引术可有效治疗OSAHS,充足的术前准备和熟练的护理配合可使手术顺利开展,并减少手术并发症的发生。

Repose系统舌骨悬吊术结合腭垂腭咽成形术对重度OSAHS合并2型糖尿病患者血糖影响的中长期比较研究

目的比较Repose系统舌骨悬吊术结合腭咽成形术与单纯腭咽成形术手术治疗对重度阻塞性睡眠呼吸暂停低通气综合征(OSAHS)合并2型糖尿病(T2DM)患者的血糖及糖代谢的影响差异。方法选择笔者医院耳鼻喉科就诊的26例重度OSAHS合并T2DM患者按随机数字表法分为两组:联合手术组(n=14)和单腭咽成形术组(n=12)。手术前后监测所有患者FBG、PBG、FINS、GHbA1c、leptin和HOMA-IR等水平的变化情况。结果总有效率方面,术后6个月及1年组间比较,联合手术组较单纯腭咽成形术组均有显著性改善(P<0.01)。在PSG监测指标上,治疗前后两组患者在AHI和LSaO2上均有不同程度的改善,而组间比较亦有统计学差异(P<0.05)。在血糖及其代谢指标方面,除FINS外,两组患者术后6个月及1年在其他各指标上较术前均有显著性改善(P<0.05),而组间比较表明,联合手术组在FBG、PBG、GHbA1c、leptin和HOMA-IR等指标上较单手术组均有明显改善(P<0.05)。结论行Repose系统舌骨悬吊术结合腭咽成形术对重度OSAHS合并T2DM患者有极大获益,推荐临床首选。

腭咽成形术联合Repose舌根牵引固定术治疗睡眠呼吸暂停低通气综合征的临床效果

目的探究腭咽成形术联合Repose舌根牵引固定术治疗睡眠呼吸暂停低通气综合征的疗效。方法选取我院2013年6月~2015年5月80例经诊断为睡眠呼吸暂停低通气综合征入院治疗的患者,按病床单双号将其分为单一组40例与联合组40例。单一组患者仅采用腭咽成形术,联合组在单一组治疗基础上加用Repose舌根牵引固定术,观察两组患者术后不良反应发生情况及患者对疗效的评价。结果联合组临床总有效率高达92.5%,高于单一组的80.0%,差异有统计学意义（P〈0.05）;术后联合组鼻咽返流、咽痛、开放性鼻音发生较单一组少,差异有统计学意义（P〈0.05）,但两组在口腔异物感上差异无统计学意义（P〉0.05）。结论腭咽成形术联合Repose舌根牵引固定术治疗睡眠呼吸暂停低通气综合征,患者术后不良反应少,长期治疗效果好。

悬雍垂腭咽成形术联合Repose舌根牵引固定术治疗OSAHS的临床效果

目的探讨悬雍垂腭咽成形术(UPPP)联合Repose舌根牵引固定术治疗阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的临床效果。方法选择我院2019年1月至2020年12月收治的80例OSAHS患者为研究对象,采用随机数字法将其分为UPPP组和联合组,每组40例。UPPP组采用UPPP术治疗,联合组在UPPP组基础上联合Repose舌根牵引固定术治疗。比较两组的临床疗效,手术前、后的X线测量参数[下咽气道间隙(V-LPW)、后气道间隙(PAS)、舌骨与下颚垂直距离(MPH)]和呼吸暂停低通气指数(AHI),并发症发生情况。结果联合组的治疗总有效率为92.50%,显著高于UPPP组的75.00%,差异具有统计学意义(P<0.05)。手术前,两组患者的X线测量参数和AHI比较,差异无统计学意义(P>0.05);手术后,联合组的V-LPW、PAS显著高于手术前及UPPP组,AHI显著低于手术前及UPPP组(P<0.05);手术后,两组的MPH均显著高于手术前,差异具有统计学意义(P<0.05),但两组间比较,差异无统计学意义(P>0.05)。联合组的并发症总发生率为12.50%,与UPPP组的7.50%比较,差异无统计学意义(P>0.05)。结论UPPP联合Repose舌根牵引固定术治疗OSAHS患者,可提高治疗效果,有利于气道塌陷的恢复与重塑,安全性较高,具有一定的临床应用价值。

Influential factors on the repose angle of desert sands

The repose angle is one of the most significant macroscopic parameters in describing the behavior of granular materials. Under a static condition, the repose angle is the steepest angle at which sediment particles can rest without motion. In this paper, we use existing data and aeolian physics to analyze the main factors that influence the repose angle of sand dunes, and we investigate different repose angles involving various states and types of materials. We have determined that different factors have differential influence on the magnitude of the repose angle. Our results show that for powdery （〈400-μm diameter） desert sands, the main influential factor on the magnitude of repose angle is the molecular force among particles. Particle size does not influence the repose angle of desert sands directly, but has an indirect impact by affecting the grit sphericity and surface roughness, of which the grit sphericity acts as a major factor. Even at the same average particle size, the repose angle differs with different grain compositions. Furthermore, with increasing unevenness in grain composition, the repose angle increases correspondingly. Sand texture also has a direct influence on the repose angle of desert sands. In two sand samples having the same grain composition but different textures, the repose angles may be different. Water content has a stronger influence on the repose angle than any other factor. However, the relationship between the repose angle and water content is not a simple direct proportion. In fact, with increasing water content, the repose angle first increases and then decreases. These research results will be useful for understanding the mechanisms of dune transport, variations of dune morphology, and the stability and fluidity of dune sands.

DEM parameter calibration of cohesive bulk materials using a simple angle of repose test

The numerical effort of discrete element method (DEM) simulations results in a general idealisation of DEM models that makes the calibration crucial to obtaining realistic simulation results. The angle of repose test has become a standard test for the calibration of DEM parameters of cohesionless bulk materials and is extensively discussed in the literature. One of the most used test methods is the pull-up test of a hollow cylinder filled with bulk material. This paper presents how this basic pull-up test can also be used for the calibration of DEM parameters of cohesive materials by changing the analysis criteria. In contrast to analysing the static angle of repose, the focus lies on the macroscopic flow behaviour during the lifting of the cylinder. Reproducible phases of flow are identified in experiments: the build-up of a stable bulk material column, the convex bending of the column, and the beginning of collapse of the column. Furthermore, the phases are independent of the size and lifting velocity. The convex bending of the bulk-material column combined with the moment of first collapse are introduced as new measurable calibration criteria. These experimental results of wet sand are used for the calibration of related DEM parameters using a simplified JKR cohesion model. The DEM calibration including an analysis algorithm that fits the experimental flow behaviour and the final selection of the relevant parameters (i.e., sliding friction coefficient, rolling friction coefficient, and cohesion energy density) is presented in detail.

STUDY ON THE ANGLE OF REPOSE OF NONUNIFORM SEDIMENT

A conception of exposure degree is used in this article to account for the hiding and exposure mechanism of nonuniform sediment transport. The force arms of particles on the bed slope are assumed to be a function of the exposure degree, which is stochastically related to the size and gradation of bed materials. Based on this conception, the formula for the angle of repose of nonuniform sediment is developed. The angle of repose of nonuniform sediment is experimentally investigated in rotation drum at the rolling motion of sediment particles. The nonuniform sediment is gotten from the mixture of two kinds of uniform sediment with different weight ratios and two experimental plans that one for changing the weight ratio of two kinds of uniform sediment from 1：9 to 9：1 and the other changing the uniform sediment size and weight ratio are used. The effect of the rotation speed and the filling degree on the angle of repose is investigated, too. Finally, the formula has been tested against a wide range of laboratory data, the prediction by the newly proposed formulas is very good.

DEM investigation of angle of repose for super-ellipsoidal particles

We explore the effect of particle shape on the angle of repose (AoR) in granular packing using a three-dimensional discrete element method.Non-spherical particles were modeled using super-ellipsoids characterized by aspect ratio and blockiness.The relationship between AoR and particle shape was examined,followed by a series of analyses on the origin of AoR from a microscopic perspective.Results show that,with blockiness deviating from unity,AoR has an approximate "M" shape that exhibits a strong to weak trend with aspect ratio,matching results of previous reports.Another finding suggests a parabolic relationship between normalized AoR and normalized coordination number,AoR increases with anisotropy related more with the anisotropy of particle orientation than with the anisotropy of contact normal.Particle shape is more likely to affect AoR by affecting the tangential force than the normal contact force.An analysis based on traction indicates that dips in stress associated with the tangential force (compared with the normal force) and non-spherical particles (compared with spheres) are more significant.For various particle shapes,AoR is positively correlated with friction mobilization but is negatively correlated with friction mobilization for various coefficient of friction.

Effects of typical corn kernel shapes on the forming of repose angle by DEM simulation

Corn kernel shape is an important feature to improve the accuracy of simulation results,also the repose angle is often used to calibrate model parameters in simulation.In this study,the effects of the corn kernel shapes on the behavior during corn kernels accumulation were investigated in detail.Firstly,the DEM models of three typical shapes of corn kernels were developed.Secondly,the influences of the corn kernel shapes on the process of forming repose angle were investigated,such as corn kernels distance change,energy conversion,and the contact number between corn kernels.Results show that the corn kernel shape has a significant effect on the repose angle formation.The irregular shape of corn kernels limit their rolling when adding the corn kernel length in one or two directions.In addition,the irregular shapes of corn kernels increase the contact number and extend simulation time.Regular shape corn kernels need to be mixed with irregular shape corn kernels to improve their flowability.Finally,observation of the trajectory of corn kernel repose angles indicates that spherical corn kernels contact the bottom plate early,and forming small cone first,then the cone becomes bigger to change the direction of other corn kernels from top to bottom.

Investigation of interaction effect between static and rolling friction of corn kernels on repose formation by DEM

The coefficient of static friction(SF),the coefficient of rolling friction(RF)for particles are two key parameters affecting the repose angle formation and flow characteristics.In this paper,the interaction effects of SF and RF on the formation process of corn repose angle was investigated by the discrete element method.Firstly,five shape kinds of corn models(horse tooth,spherical cone,spheroid,oblate,and irregular shape)were established.Secondly,aluminum cylinder and organic glass box were used to conduct the simulation experiments with taking SF and RF as independent factors and seeing the repose angle as dependent value.Based on simulation results the regression equations were established.Simulation results showed the relation between two factors and the rotational kinetic energy is not nonlinear,and SF does not significantly restrict the flow of corn models after increasing the flow direction,and the effect of SF on the contact number between corns and the bottom plate is remarkable,while the effect of RF on the contact number is not remarkable.Finally,the interaction effect of two factors on the repose angle was analyzed by variance analysis and results showed SF and RF all have a significant impact on the repose angle.Moreover,their interaction effect has an impact on the repose angle.

Determination of key soil characteristic parameters using angle of repose and direct shear stress test

Discrete element modelling(DEM)is a numerical method for examining the dynamic behavior of granular media.In order to build an accurate simulation model and provide more comprehensive soil characteristic parameters for the design and optimization of various soil contact machinery,in this paper,the discrete element simulation method(EDEM)combined with experimental approach is used to investigate the soil contact characteristic parameters in East Asia.In this study,Hertze-Mindlin(no slip)was used as a particle contact model by taking particle contact parameters and soil JKR(Johnson-Kendall-Roberts)surface energy as determinants,and repose angle,internal friction angle,and cohesive force as evaluation indexes.The method of Plackett-Burman,Stepest ascent,and Box-Behnken were used to gradually reduce the range of parameters needed for simulation until the most accurate value was determined.The results show that the restitution coefficient,static friction coefficient,and rolling friction coefficient between soil particles have significant effects on the DEM model,and their value of them are 0.596,0.725,and 0.16,respectively.Based on these parameters used for the repose angle test and direct shear stress test,the value of repose angle is 31.97°,the internal friction angle is 27.61°,and the cohesive force is 33.06 kPa.The relative errors with the actual measured values are 9.54%,1.87%,and 2.31%,respectively.In order to further test whether the simulation parameters of soil obtained by repose angle test and direct shear stress test are consistent with the real soil,comparison test between field test and discrete element simulation was used.The results show that the error in height of ridge between the simulated soil and the actual soil is 4.06%,which is within the acceptable range.It also indicates that the calibrated and optimized soil simulation model can accurately represent the real soil.The research provides theoretical basis and technical support for the study of soil contact parts by using the discrete element method,combined with repose angle test and direct shear stress test.

Research on the Relationship between Grain Composition and Repose Angle of Coal Gangue in Dongkuang Mine, Heshan City, Guangxi, China

Heshan, a city in Southwest China, has been built over an old coal mining area. Due to low level of reclamation, coal gangue had been stacked in large heaps and caused geological environ- mental problems. To facilitate designing management project of coal gangue, we made an investigation of the largest coal gangue heap in Dongkuang Mine of Heshan. Firstly, the grain composition of coal gangue was estimated through the sieving method, then the representative grading curve was drawn through the statistics method of coarse grain content, and lastly the relationship between the repose an- gle and grain grading was studied by piling up coal gangue with different mix proportion. The result indicates that there is a wider range of grain size in the upper part of coal gangue heap, and the repre- sentative grain grading is well graded and easy to be compacted as filling materials. Besides, the wavy relationship curve of repose angle and coarse grain content shows that the content of 70% is the infiec- tion point of ascent stage and 85% the inflection point of descent stage of the repose angle. What＇s more, the repose angle corresponding to the representative grading of coal gangue is approximately 38.4° and this has guiding significance for management project of coal gangue.

Experimental study on the angle of repose of pulverized coal

An experimental study on the angle of repose （AoR） of pulverized coal with different particle sizes and different moisture contents （MC） was conducted. Three different measurement methods, free-base piling, fixed-base piling and sliding, were used. The data were analyzed by one-way and two-way analysis of variance. The results showed that the AoRs of pulverized coal with particle sizes smaller than 150 μm were in the range of 30-50°. The characterization of the flowability of pulverized coal was some cohesiveness or true cohesiveness. The increase of MC will increase AoR and thus decrease the flowability of the powder. However, the particle size effect is bifurcated. Below a critical size, the decrease of particle size decreases the flowability; while above the critical size, the decrease of particle size increases the flowability. It was found that the value of the critical size strongly depends on the powder density. Moreover, the AoR dependence on particle size could be linked with the Geldart＇s particle classification. The critical size at the turning point is on the boundary between Group A and Group B in Geldart＇s classification diagram. Based on the experimental results, there is no significant cross interaction between particle size and MC. The AoRs measured by free-base method and fixed-base method are close, but both remarkably smaller than that measured by the sliding method.

Effect of granular size on the angle of repose in the chute

Avalanche in the chute has been studied to examine how the sizes of granules affect the angle of repose θr when the width of the chute is fixed. The results show that the angle of repose in the chute has exponential decay with λ,which is the reciprocal of granular diameter d. The fluctuation of the angle of repose is also studied during the chute being tilted,and the results indicate that the fluctuation of the angle of repose increases with the increase of granular diameter d.

Angle of repose in the numerical modeling of ballast particles focusing on particle-dependent specifications:Parametric study

The discrete element method(DEM)is widely used in the realistic simulation of the shapes of particles.Researchers have considered the simplification of particle shapes owing to the high computational cost of such simulation.In this regard,the modeling of calibrated particles is a major challenge owing to the simultaneous effects of particle properties.The angle-of-repose test is a standard test method used to calibrate the bulk behavior of simulated particles.In the present study,the hollow-cylinder(slump)test was modeled for the verification of discrete element simulations.In this regard,a sensitivity analysis was conducted for all effective parameters,namely the static friction,rolling friction,restitution coefficient,sphericity,roundness,particle size distribution,and number of ballast particles.The results indicate that the rolling friction,roundness,number of particles,and size of particles are the most important parameters in the determination of the angle of repose(AOR).For particles in the range of ballast(20-60 mm),the effect of the number of particles on the angle of repose is reduced when the number is greater than 426.Additionally,it is concluded that angular particles can be replaced with sub-angular particles(R≈0.2-0.45)with a higher rolling friction coefficient(μ_(r)>0.14).

舌根悬吊治疗伴有舌后坠阻塞性睡眠呼吸暂停低通气综合征的疗效观察

目的：评估悬雍垂腭咽成形术（ UPPP）联合Reposes系统舌根悬吊治疗伴有舌后坠阻塞性睡眠呼吸暂停低通气综合征（ OSAHS）的可行性和临床效果。方法回顾分析本科2010年7月～2012年12月行UPPP联合 Reposes 系统舌根悬吊治疗的14例伴有舌后坠 OSAHS 患者的临床资料。结果治愈3例（21．4％）、显效10例（71．4％）、有效1例（7．1％）。术前平均呼吸暂停低通气指数（ AHI）为50．7±19．4，术后平均AHI 为8．1±4．5（P＜0．05）；术前平均最低血氧饱和度（LSaO2）为66．6％±7．7％，术后平均LSaO2为78．6％±7．4％（P＜0．05）；术前Epworth 嗜睡量表（ESS）平均评分为（16．9±1．8）分，术后ESS平均评分为（8．3±2．4）（P＜0．05），差异均有统计学意义。主观症状均明显改善，术后1个月随访，未出现反流、吞咽及说话困难。结论 UPPP联合Reposes系统舌根悬吊治疗后，患者AHI、LSaO2及ESS指标均改善明显，该联合术式可作为治疗伴有舌后坠OSAHS的一个选择。（中国眼耳鼻喉科杂志，2015，15：13-15）

舌根牵引加改良悬雍垂腭咽成形术治疗Ⅳ型阻塞性呼吸睡眠暂停低通气综合征的围手术期观察与护理

目的探讨Repose舌根牵引术治疗Ⅳ型阻塞性睡眠呼吸暂停低通气综合征(OSAHS)的围手术期护理方法。方法选择23例行Repose舌根牵引术的Ⅳ型OSAHS患者,在手术前后给予正确的护理及健康教育。结果全部患者无严重并发症。术后随访1年,大多数病例呼吸暂停次数及时间明显减少,呼吸紊乱指数减少,血氧饱和度提高,患者自觉症状好转,夜间无憋气、打鼾,晨起无头昏、嗜睡等不适。结论 Repose舌根牵引术对Ⅳ型OS-AHS患者有良好疗效,而正确的围手术期护理是提高疗效的重要保证。

Measurement and Influence Factors of the Flowability of Microcapsules with High-content β-Carotene

The flowability of five kinds of microencapsulation powders,with differentβ-carotene contents and by two alternative particle-forming technologies i.e.spray-drying and starch-catching beadlet technology,was meas- ured.The actual flow properties of the five powders were compared based on bin-flow test,and three flow indexes (Hausner ratio,repose angle and flow index)were measured.It was found that the repose angle is the most suitable index to reflect the flowability of these powders for the particle properties would not be altered due to compaction or tapping during the measuring process.Particle size and particle size distribution play most important roles in the flowability of these granular materials,which was also influenced by other factors like shape,surface texture,sur- face roughness,etc.Microcapsules with wall material of gelatin and a layer of modified starch absorbed on the sur- face showed excellent flowabilities and good mechanical properties,and they are favorable for tabletting to supply β-carotene.