Scattering of SH-wave by multiple circular cavities in half space

In this paper,an analytic method is developed to address steady SH-wave scattering and perform dynamic analysis of multiple circular cavities in half space.The scattered wave function used for scattering of SH-waves by multiple circular cavities,which automatically satisfies the stress-free condition at the horizontal surface,is constructed by applying the symmetry of the SH-wave scattering and the method of multi-polar coordinates system.Applying this scattered wave function and method of moving coordinates,the original problem can be transformed to the problem of SH-wave scattering by multiple circular cavities in the full space.Finally,the solution of the problem can be reduced to a series of algebraic equations and solved numerically by truncating the infinite algebraic equations to the finite ones.Numerical examples are provided for case with two cavities to show the effect of wave number,and the distances between the centers of the cavities and from the centers to the ground surface on the dynamic stress concentration around the cavity impacted by incident steady SH-wave.

Study on the influences of interaction behaviors between multiple combustion-gas jets on expansion characteristics of Taylor cavities

The purpose of this study is to investigate means of controlling the interior ballistic stability of a bulk-loaded propellant gun（BLPG）.Experiments on the interaction of twin combustion gas jets and liquid medium in a cylindrical stepped-wall combustion chamber are conducted in detail to obtain time series processes of jet expansion,and a numerical simulation under the same working conditions is also conducted to verify the reliability of the numerical method by comparing numerical results and experimental results.From this,numerical simulations on mutual interference and expansion characteristics of multiple combustion gas jets（four,six,and eight jets） in liquid medium are carried out,and the distribution characteristic of pressure,velocity,temperature,and evolutionary processes of Taylor cavities and streamlines of jet flow Held are obtained in detail.The results of numerical simulations show that when different numbers of combustion gas jets expand in liquid medium,there are two different types of vortices in the jet flow field,including corner vortices of liquid phase near the step and backflow vortices of gas phase within Taylor cavities.Because of these two types of vortices,the radial expansion characteristic of the jets is increased,while changing numbers of combustion gas jets can restrain Kelvin-Helmholtz instability to a certain degree in jet expansion processes,which can at last realize the goal of controlling the interior ballistic stability of a BLPG.The optimum method for both suppressing Kelvin-Helmholtz instability and promoting radial expansion of Taylor cavities can be determined by analyzing the change of characteristic parameters in a jet flow field.

Prediction of cavity growth rate during underground coal gasification using multiple regression analysis

During underground coal gasification （UCG）, whereby coal is converted to syngas in situ, a cavity is formed in the coal seam. The cavity growth rate （CGR） or the moving rate of the gasification face is affected by controllable （operation pressure, gasification time, geometry of UCG panel） and uncontrollable （coal seam properties） factors. The CGR is usually predicted by mathematical models and laboratory experiments, which are time consuming, cumbersome and expensive. In this paper, a new simple model for CGR is developed using non-linear regression analysis, based on data from 1 l UCG field trials. The empirical model compares satisfactorily with Perkins model and can reliably predict CGR.

A SINGLE-CAVITY MULTIPLE-DEVICE HARMONIC OSCILLATOR AT W-BAND

The equivalent circuit of single-cavity multiple-device fundamentaloscillator(SCMDFO)and that of single-device harmonic oscillator(SDHO)proposed byK.Kurokawa and K.Solbach,respectively,are extended and applied to a single-cavitymultiple-device harmonic oscillator(SCMDHO).By means of describing the functions ofnonlinearity of Gunn diodes,the performances of the SCMDHO are analyzed.It is foundthat the voltage amplitudes are similar to those of SDHO,and the ratio of maximum pow-er of harmonic to that of fundamental is identical to that in SDHO when the devices havesame parameters.The harmonic injection locking behavior is also investigated.The injec-tion locking range is greater than that of SDHO if locking gain remains constant.A2-Gunn diode harmonic oscillator was designed.It delivers 30mW output power at103GHz.The mechanical tuning range is 4.15GHz when the output power remains morethan 10mW.The desired operation mode is stable.

Multiple neurofibromas plus fibrosarcoma with familial NF1 pathogenicity:A case report

BACKGROUND Neurofibromatosis(NF)is a genetic disease consisting of seven types,of which types 1 to 4 are caused by a dominant autosomal gene mutation;such disease sometimes arises in patients with NF type 1.However,it remains unclear whether the origin of neurofibrosarcoma is directly linked to the incidence of NF type 1,as no reports have been published on this issue.Here,we report a case of NF1-positive multiple neurofibromas with malignant fibrosarcomatous transformation in the pleural cavity.CASE SUMMARY A 51-year-old male was admitted to our hospital due to fever accompanied by coughing,chest tightness and asthma for more than one month.The preliminary diagnosis was NF type 1,which was pathologically confirmed by a subsequent thoracoabdominal subcutaneous biopsy.The definitive diagnosis was neurofibrosarcoma with a pathogenic NF1 gene.The patient refused surgery and chemoradiotherapy,and died two months later.NF is a genetic disease consisting of seven types,of which types 1 to 4 are caused by a dominant autosomal gene mutation.The case reported belongs to the class of NF1-positive dominant inheritance.Neurofibrosarcoma is a malignant tumor derived from cells surrounding the peripheral nerves.However,due to the lack of previous reports,it remains unclear whether the origin of neurofibrosarcoma is directly linked to the incidence of NF type 1.CONCLUSION We report the first case of NF1-positive multiple neurofibromas with malignant fibrosarcomatous transformation in the pleural cavity.

Intensity modulation in single-mode microchip Nd：YAG lasers with asymmetric external cavity

Intensity modulation induced by the asymmetric external cavity in single-mode microchip Nd：YAG lasers is prosented. Two kinds of experimental results are discussed based on multiple feedback effects. In one case, the intensity modulation curve is a normal sine wave, whose fringe frequency is four times higher than that of a conventional optical feedback system, caused by multiple feedback effects. In the other case, the intensity modulation curve is the overlapping of the above quadruple-frequency signal and conventional optical feedback signal, which is determined by the additional phase difference induced by the asymmetric external cavity. The theoretical analyses are in good agreement with the experimental results. The quadruple-frequency modulation of the laser output intensity can greatly increase the resolution of displacement measurement of an optical feedback system.

Controlling factors of remaining oil distribution after water flooding and enhanced oil recovery methods for fracturecavity carbonate reservoirs in Tahe Oilfield

Based on comprehensive analysis of core, well logging, seismic and production data, the multi-scale reservoir space, reservoir types, spatial shape and distribution of fractures and caves, and the configuration relationship with production wells in fracture-cavity carbonate reservoirs were studied systematically, the influence of them on the distribution of residual oil was analyzed, and the main controlling factors mode of residual oil distribution after water flooding was established. Enhanced oil recovery methods were studied considering the development practice of Tahe oilfield. Research shows that the main controlling factors of residual oil distribution after water flooding in fracture-cavity carbonate reservoirs can be classified into four categories: local high point, insufficient well control, flow channel shielding and weak hydrodynamic. It is a systematic project to improve oil recovery in fracture-cavity carbonate reservoirs. In the stage of natural depletion, production should be well regulated to prevent bottom water channeling. In the early stage of waterflooding, injection-production relationship should be constructed according to reservoir type, connectivity and spatial location to enhance control and producing degree of waterflooding and minimize remaining oil. In the middle and late stage, according to the main controlling factors and distribution characteristics of remaining oil after water flooding, remaining oil should be tapped precisely by making use of gravity differentiation and capillary force imbibition, enhancing well control, disturbing the flow field and so on. Meanwhile, backup technologies of reservoir stimulation, new injection media, intelligent optimization etc. should be developed, smooth shift from water injection to gas injection should be ensured to maximize oil recovery.

Numerical Investigation of Lid-Driven Deep Cavity with Local Grid Refinement of MRT-LBM

In the case of lid-driven deep cavity flow, the effects of different resolutions of local grid refinement have been studied in the frame of multiple relaxation times (MRT) lattice Boltzmann method (LBM). In all the cases, the aspect ratio and Reynolds number are set as 1.5 and 3.200, respectively. First, the applied method is validated by comparing it with two reported works, with which agreements are reached. Then, six separate degrees of local grid refinement at the upper left corner, i.e. purely coarse grid, including 1/64, 1/32, 1/16, 1/8, 1/4 refinements of the lattice number in the width direction have been studied in detail. The results give the following indications:① The refinement degrees lower than 1/8 produce similar results;② For single corner refinement, 1/4 refinement is adequate for clearing the noises in the singularity zone to a large extent;③ New noise around the interface between coarse and fine zones are introduced by local grid refinement. Finally, refinement of entire subzone neighboring the lid is examined to avoid introducing new noises and it has been found effective.

EFFECTIVE EIGENVALUE FOR THE INTENSTTY CORRELATION OF A LASER WITH MULTIPLICATIVE WHITE NOISE

Exact formulas of the effective eigenvalues in a single-mode laser with multiplicative white noise are derived through the full saturation laser model and the third order laser model.Compared with the numerical computations and the experimental measurements,excellent agreement is obtained for the full saturation theory,and hence the cavity decay rate for the experimental electric field can be concluded easily.Relatiely large errors occur in the third order theory and the measured data.

以多浆膜腔积液为首发症状的IgD型多发性骨髓瘤的临床研究

目的 探讨多发性骨髓瘤(MM)浆膜腔浸润的机制,并探讨浆膜腔积液在MM诊断、治疗中的意义和浆膜腔积液细胞形态学的诊断价值。方法 分析该院收治的1例以多浆膜腔积液为首发症状的IgD型MM患者从入院到诊断过程;同时以“浆膜腔积液”“多发性骨髓瘤”为关键词,对中国知网和万方数据库2020年1月至2023年12月发表的文献进行文献检索。结果 首先从该例患者浆膜腔积液细胞形态学检查发现大量异常浆细胞,进一步确诊为MM(IgDλ型);文献检索结果:共检索到中文文献15篇,英文文献3篇,排除重复文献,最终保留中文文献7篇,英文文献2篇。结合病例和文献复习发现,以多浆膜腔积液为首发症状的MM是一种极为罕见的表现,而且骨髓瘤细胞浸润浆膜腔后通常会发生形态变异,容易误诊、漏诊。结论 对多浆膜腔积液患者应及时行浆膜腔积液检查,明确浆膜腔积液的良、恶性,以降低MM等恶性疾病的误诊率、漏诊率。

异形多腔钢管混凝土分叉短柱抗震性能试验及数值计算

针对某超高层巨型框架结构中异形截面多腔钢管混凝土(concrete-filled steel tube, CFT)分叉柱,为研究截面加强构造对分叉短柱抗震性能的影响,进行了4个试件在竖向轴压力及水平往复两次的低周反复荷载下的抗震性能试验研究,试件上部为五边形四腔体钢管混凝土双柱肢,下部为八边形十三腔体钢管混凝土单柱肢,以此形成分叉柱;研究的截面构造包括四种:基本构造,钢管钢板整体加厚构造,距中和轴较远的钢管角部钢板内表面贴焊等肢角钢的局部钢板加厚构造,距中和轴较远的钢管腔体内置圆钢管构造。基于试验结果及截面构造特点,进行了数值计算。试验及数值计算结果表明:异形截面多腔钢管混凝土分叉短柱的破坏主要发生在上柱根部分叉截面处,表现为距离中性轴较远处的钢板撕裂以及局部焊缝开裂引起的整块钢板撕裂;内置圆钢管的加强构造承载力提高7.6%、变形能力提高14.4%,综合耗能能力最强,局部钢板加强构造承载力提高9.2%、变形能力下降18.7%,钢管钢板整体加厚构造承载力略有提高、但变形能力下降较多;提出的异形多腔钢管混凝土柱简化建模方法计算效率较高,精度满足工程设计要求。

含覆层圆柱空腔的声学材料水下吸声特性研究

针对增加水下空腔谐振型声学材料的孔隙率导致吸声系数下降的问题,在声学材料的圆柱空腔外包覆多层覆层结构,提出了含覆层圆柱空腔的声学材料。采用有限元方法计算了声学材料的吸声系数,相比含圆柱空腔的声学材料,覆层圆柱空腔使声学材料具有更低的吸声频带和更高的吸声能力。通过计算单极共振频率揭示吸声机理,覆层圆柱空腔比圆柱空腔具有更低的单极共振频率,使声学材料的频带更低。功耗密度场分布结果表明,多层覆层结构提供了更多的交界面,声波的散射增强从而声能损耗加剧。研究了多层覆层结构的模量和厚度分布形式对吸声性能的影响,模量呈正梯度变化与厚度呈负梯度变化的多层覆层结构分布形式能够使吸声覆盖层获得较好的低频吸声性能。

1例伊马替尼致胃肠道间质瘤术后多浆膜腔积液患者的个体化治疗实践

目的促进伊马替尼的临床安全应用。方法临床药师参与1例伊马替尼致胃肠道间质瘤(GIST)切除术后多浆膜腔积液患者的临床诊疗过程,结合患者的病史、用药史,并通过治疗药物监测(TDM)反馈伊马替尼的稳态血药浓度谷值(Cssmin)进行药品不良反应关联性评价。对症治疗后,患者重启伊马替尼治疗,继续基于TDM和疗效调整伊马替尼给药剂量。结果患者停用伊马替尼48 h后,伊马替尼的血药浓度为1556.8 ng/mL,预测其Cssmin为3913.8 ng/mL,远高于GIST的推荐治疗浓度(1100 ng/mL);继续予利尿治疗,病情缓解后带药出院。经8次伊马替尼TDM,调整剂量为每天1次,每次0.2 g,血药浓度稳定在1700 ng/mL左右。结论临床药师利用TDM调整伊马替尼的剂量,可促进临床GIST患者安全使用伊马替尼。

基于Comsol的纵振宽带水声换能器优化

为了使换能器得到更大的工作带宽以及降低发射电压响应起伏,提出一种空腔式多激励纵振水声换能器,通过有限元分析,研究换能器在不同阶段的振动模态以及在空气和水中的谐响应特征,实现水声换能器的带宽发射。通过对各个部件的材料、尺寸优化后,得到换能器的工作带宽10~31.5 kHz,发射电压响应起伏5.1 dB以及发射电压响应幅值127 dB。根据优化后的参数加工制作了纵振水声换能器样机,并在消声水池进行实物测试,得到可用工作带宽为11.5~30.5 kHz,发射电压响应起伏在±3 dB,平均幅值126 dB。试验结果和计算机仿真结果基本吻合,符合预期要求。

自由运行光纤激光器产生GHz光频梳的模式过滤技术

将光频梳的重复频率提高到GHz级别,不仅可以实现更广带宽、更高速的气体光谱探测,还在天文光谱仪精密定标、大容量光通信网络等领域发挥重要作用。基于理论模拟,设计并搭建模式滤波腔,使用Pound-Drever-Hall技术,对全光纤锁模激光器进行模式过滤。成功实现了重复频率从97.4 MHz到1.75 GHz的显著提升,并取得了23 dB的最小边模抑制比。四组对比实验结果表明,当高阶模式与光频梳模式重叠时,边模抑制比会降低。光频梳的原始重复频率越大,可以获得更高的边模抑制比。研究成果有望进一步提高光纤光频梳的重复频率,推动低成本、便捷的光频梳应用。

Analysis of Time-domain Electromagnetic Scattering Problem by Multiple Cavities

The time-domain multiple cavity scattering problem,which arises in diverse scientific areas,has significant industrial and military applications.The multiple cavities,embedded in an infinite ground plane,is filled with inhomogeneous media characterized by variable dielectric permittivities and magnetic permeabilities.Corresponding to the transverse electric,the scattering problem can be studied by the Helmholtz equation in frequency domain and wave equation in time-domain respectively.A novel transparent boundary condition in time-domain is developed to reformulate the cavity scattering problem into an initial-boundary value problem in a bounded domain.The well-posedness and stability of the reduced problem are established.Moreover,a priori energy estimates for the electric field is obtained with minimum regularity requirement for the data and an explicit dependence on the time by studying the wave equation directly.

Multiple Relaxation Time Lattice Boltzmann Simulation of 2D Natural Convection in a Square Cavity at High Rayleigh Numbers

Natural convection in a square cavity at high Rayleigh numbers is simulated by multiple relaxation time(MRT)lattice Boltzmann method(LBM)with a separate distribution function to solve the temperature.The Rayleigh numbers examined here range from Ra=103 to Ra=10^(8).For Rayleigh numbers below 10^(8),the flow remains stationary and transition occurs beyond Ra=2×10^(8).Unsteady results at higher Rayleigh numbers(Ra=10^(9) and Ra=10^(10))are also investigated.To the best of our knowledge,this is the first accurate study which involves the high Rayleigh numbers Ra=10^(9),10^(10).

TCRP联合宫腔负压吸引术治疗多发性EP合并不孕症的效果

目的探讨多发性子宫内膜息肉(EP)合并不孕症患者予以宫腔镜子宫内膜息肉电切术(TCRP)联合宫腔负压吸引术治疗对患者性生活质量、妊娠结局的影响。方法按照手术方法将许昌龙湖医院2021年1月18日至2024年1月18日期间确诊的127例多发性EP合并不孕症患者分组,对照组63例给予TCRP治疗,观察组64例在对照组的基础上予以宫腔负压吸引术治疗。对比两组患者的手术指标、性生活质量和妊娠结局。结果观察组手术时间较对照组短,围术期并发症发生率较对照组低,术中出血量较对照组多(P<0.05);相较于对照组,观察组术后各维度BISF-W评分更高(P<0.05);术后随访12个月,观察组妊娠成功率(31.25%)较对照组(14.29%)高(P<0.05)。结论TCRP联合宫腔负压吸引术治疗多发性EP合并不孕症患者可以缩短手术时间,降低围手术期并发症发生率,从而改善患者性生活质量,提高妊娠成功率。

On acoustic performance for viscoelastic coating containing axisymmetric cavities using the multiple scattering method

A semi-analytical/numerical model based on the multiple scattering （MS） method has been established for analyzing the effect of acoustic performance on main energy attenua- tion mechanism in viscoelastic coating containing axisymmetric cavities. The basic functions of stress and displacement of the axisymmetric cavity surface are derived in the system of spheri- cal coordinates. The transition matrix between the incident wave and the scattering wave are obtained by the numerical integral of the basic functions of the cavity surface. The reflection, transmission and absorption performance of viscoelastic materials containing periodic cavities are calculated using the MS method and the wave propagating theory of the multi-layered medium. The results indicate that low frequency energy is mainly attenuated through cavity resonance. The resonant properties are found to be very sensitive to the boundary conditions. The coupling of the double-cavity is capable of extending the absorption to even lower fre- quencies. The absorption performance of the viscoelastic coating in the high frequency range is independent of the backing material. Its energy attenuation depends mainly on acoustic properties of cavity scattering and mode conversion.

多馈源箱式加热器的微波场均匀性仿真分析

采用Ansoft HFSS仿真软件对多馈源箱式微波加热器,在不同开口位置、不同数量和分段组合的条件下,进行了微波场均匀性的模拟仿真分析研究,得出6只磁控管馈入微波能采用单面开口配置获得的微波场更为均匀,不同磁控管组合馈入微波能来调节微波功率会引起加热器内的微波场分布不均匀,分段组合使得加热器内总叠加的微波场分布均匀。