Control of Nozzle Flow Using Rectangular Ribs at Sonic and Supersonic Mach Numbers

This study deals with base pressure management in a duct for various values of the Mach number(M),namely,Mach number corresponding to sonic and four supersonic conditions.In addition to the Mach number,the nozzle pressure ratio(NPR),the area ratio,the rib dimension,and the duct length are influential parameters.The following specific values are examined at M=1,1.36,1.64,and 2,and NPRs between 1.5 and 10.The base pressure is determined by positioning ribs of varying heights at predetermined intervals throughout the length of the square duct.When the level of expansion is varied,it is seen that the base pressure initially drops for overexpanded flows and increases for under-expanded flows.When ribs are present,the flow field in the duct and pressure inside the duct fluctuate as the base pressure rises.Under-expanded flows can achieve a base pressure value that is suitably high without experiencing excessive changes in the duct flow in terms of static pressure if a rib height around 10%of the duct height close to the nozzle exit is considered.Rectangular rib passive control does not negatively affect the duct’s flow field.

Current practice in autologous rib and costal-cartilage harvest for rhinoplasty:A systematic review

Background:Autologous costal grafts are used universally in clinical practice for rhinoplasty and reconstruction.However,surgeons worldwide have not agreed on the details of graft harvesting,including rib selection,side preference,operation mode,cutting methods,and handling of the periosteum and perichondrium.This study aimed to provide an overview of the novel techniques used for auto-rib harvesting in rhinoplasty within the past 5 years and identify potential avenues for future research.Methods:We searched for related articles in PubMed,Embase,and Web of Science from 2019 to 2023,summa-rized crucial but controversial steps in recent practice,and analyzed their theoretical basis and clinical feasibility.Results:Auto-rib and cartilage open harvest is still mainstream in rhinoplasty and reconstruction,with the 5th to 8th ribs and cartilage being the most used.The laparoscopic harvest is gaining attention,being second only to the open harvest,with the 9th/10th ribs and cartilages being particularly convenient.The clinical applications of full-cut and split-cut methods differ in their advantages.Except for some special reasons,almost all studies tended to preserve the periosteum and perichondrium in situ,and few surgeons chose to harvest the grafts on the left side.Conclusion:Multiple techniques have emerged,requiring surgeons to balance the benefits and risks of various strategies at each step.New theories and techniques should be fully tested promptly and in clinical practice before wide application.Overall,a professional consensus is needed for better directivity,precision,and stability in clinical practice.

The influence of inter-band rock on rib spalling in longwall panel with large mining height

In order to improve rib stability,failure criteria and instability mode of a thick coal seam with inter-band rock layer are analysed in this study.A three-dimensional mechanical model is established for the rib by considering the rock layer.A safety factor is defined foy the rib,and it is observed that the safety factor exhibits a positive correlation with the thickness and strength of the inter-band rock.A calculation method for determining critical parameters of the rock layer is presented to ensure the rib stability.It is revealed that incomplete propagation of the fracture at the hard rock constitutes a fundamental prerequisite for ensuring the rib stability.The influence of the position of the inter-band rock in the coal seam on failure mechanism of the rib was thoroughly investigated by developing a series of physical models for the rib at the face area.The best position for the inter-band rock in the coal seam is at a height of 1.5 m away from the roof line,which tends to provide a good stability state for the rib.For different inter-band rock positions,two ways of controlling rib by increasing supports stiffness and flexible grouting reinforcement are proposed.

Bearing mechanism of roof and rib support structure in automatically formed roadway and its support design method

Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the successful application of the new method.In order to realize the stability control of the roadway surrounding rock,the mechanical model of the roof and rib support structure is established,and the influence mechanism of the automatically formed roadway parameters on the compound force is revealed.On this basis,the roof and rib support structure technology of confined lightweight concrete is proposed,and its mechanical tests under different eccentricity are carried out.The results show that the bearing capacity of confined lightweight concrete specimens is basically the same as that of ordinary confined concrete specimens.The bearing capacity of confined lightweight concrete specimens under different eccentricities is 1.95 times higher than those of U-shaped steel specimens.By comparing the test results with the theoretical calculated results of the confined concrete,the calculation method of the bearing capacity for the confined lightweight concrete structure is selected.The design method of confined lightweight concrete support structure is established,and is successfully applied in the extra-large mine,Ningtiaota Coal Mine,China.

Numerical Simulation Analysis of Welded Joints in Arch Ribs of Large Span Steel Pipe Arch Bridges

In order to study the residual stress distribution law of welded joints of arch ribs of large-span steel pipe concrete arch bridges,numerical simulation of temperature,stress and strain fields based on ABAQUS for welded joints of arch-ribbed steel tubes using 7-,8-and 9-layer welds is carried out and its accuracy is demonstrated.The steel pipe welding temperature changes,residual stress distribution,different processes residual stress changes in the law,the prediction of post-weld residual stress distribution and deformation are studied in this paper.The results show that the temperature field values and test results are more consistent with the accuracy of numerical simulation of welding,the welding process is mainly in the form of heat transfer;Residual high stresses are predominantly distributed in the Fusion zone(FZ)and Heat-affected zone(HAZ),with residual stress levels tending to decrease from the center of the weld along the axial path,the maximum stress appears in the FZ and HAZ junction;The number of welding layers has an effect on the residual stress distribution,the number of welding layers increases,the residual stress tends to decrease,while the FZ and HAZ high stress area range shrinks;Increasing the number of plies will increase the amount of residual distortion.

Rib Osteosynthesis for Sub-Acute Management of a Flail Chest in a Tertiary Centre in a Low-Middle Income Country of Sub-Saharan Africa: Case Report at Douala Laquintinie Hospital

Background: Costal fracture surgical is still a debate, therefore we shall select between early and delay surgical management. Case Report: We are reporting two cases of post road traffic clash delay ribs fractures osteosynthesis involving a 63-year-old man with multistage fractures on the left and pulmonary pinning of one of the costal arches, complicated by a homolateral haemothorax and a 41-year-old man with a bilateral flail chest. Conclusion: The simple postoperative course and the immediate postoperative improvement in the patient’s clinical respiratory condition enabled us to discuss the time frame for management, in this case the indication for early or later surgery.

Application of Grooved Negative Pressure Drainage Tube in Surgical Stabilization of Rib Fractures

Objective: To explore the application value of disposable grooved negative pressure drainage tubes in rib fracture incision and internal fixation. Methods: Seventy-five patients admitted to our Department of Trauma Surgery from June 2022 to April 2024 who underwent rib fracture osteotomy and internal fixation were selected. According to the types of drainage tubes left in the patients after the operation, they were divided into the observation group (35 cases who were left with disposable grooved negative pressure drainage tubes) and the control group (40 cases who were left with closed silicone thoracic drainage tubes). Comparison of chest drainage, pain, postoperative complications, secondary chest penetration rate, drain placement time, hospitalization time, and treatment costs were compared between the two groups. Results: The total postoperative chest drainage volume of the observation group was less than that of the control group (P < 0.05);the degree of pain, the incidence of postoperative complications, and the rate of secondary chest puncture in the observation group were lower than that of the control group three days after the operation (P < 0.05);and the time of drain placement in the observation group was shorter than that of the control group (P < 0.05). Conclusion: The application of disposable grooved negative pressure drainage tubes in rib fracture incision and internal fixation can significantly improve patients’ postoperative pain and discomfort, reduce complications, lower the rate of secondary chest penetration, promote patients’ postoperative recovery, decrease the amount of postoperative chest drainage, and shorten the time of drain placement, which is worthy of clinical promotion and application.

米曲霉RIB40高效同源重组和尿苷/尿嘧啶营养缺陷型菌株的构建

目的:以米曲霉RIB40为出发菌株,构建具有高同源重组效率的营养缺陷型菌株。方法:首先通过同源重组技术和5-氟乳清酸(5-Fluoroorotic Acid,5-FOA)对尿苷/尿嘧啶营养缺陷的筛选作用,获得AopyrG基因缺失的米曲霉RIB40。然后利用烟曲霉AfpyrG基因替换Aoku70得到ΔAoku70敲除菌株,再通过5-FOA的筛选作用使得ΔAoku70菌株基因组发生自身环化,丢失AfpyrG基因。最后为了检验ΔAoku70ΔAopyrG菌株的可用性,将编码红色荧光蛋白的mCherry基因敲入至双突变菌株的组蛋白H2B基因上,并通过激光共聚焦显微镜观察红色荧光蛋白质的亚细胞定位。结果:通过AopyrG和Aoku70的双基因敲除,获得了高同源重组效率的营养缺陷型菌株ΔAoku70ΔAopyrG。用激光共聚焦观察到红色荧光蛋白定位于细胞核,表明ΔAoku70ΔAopyrG菌株可用于米曲霉的基因改造。结论:ΔAoku70ΔAopyrG菌株可作为一个高同源重组效率的营养缺陷型出发菌株用于今后米曲霉RIB40的遗传改良。

抗dsDNA抗体阴性的系统性红斑狼疮患者抗Sm抗体、抗Rib⁃P抗体水平及临床意义

目的探讨抗Sm抗体、抗Rib-P抗体对抗双链DNA(dsDNA)抗体阴性的系统性红斑狼疮的诊断价值。方法选择2020年8月—2021年8月收治的抗dsDNA抗体阴性的系统性红斑狼疮68例作为研究组,同期72例非系统性红斑狼疮的自身免疫性疾病患者作为对照组,同期体检健康者78例作为健康组。采用化学发光法检测3组抗Sm抗体、抗Rib-P抗体,随后采用受试者工作特征(ROC)曲线分析抗Sm抗体、抗Rib-P抗体对抗dsDNA抗体阴性的系统性红斑狼疮的诊断价值,以及研究组抗Sm抗体、抗Rib-P抗体与临床表现、实验室指标的关系。结果研究组抗Sm抗体、抗Rib-P抗体阳性率均高于对照组、健康组(P<0.05)。ROC曲线分析结果显示,抗Sm抗体联合抗Rib-P抗体诊断抗dsDNA抗体阴性的系统性红斑狼疮的曲线下面积及敏感度均高于单一指标诊断。研究组抗Sm抗体、抗Rib-P抗体阳性者蛋白尿发生率及C3阳性率明显高于抗Sm抗体、抗Rib-P抗体阴性者(P<0.05)。结论抗Sm抗体、抗Rib-P抗体对抗dsDNA抗体阴性的系统性红斑狼疮具有一定的诊断价值,且二者联合诊断价值更佳,有望作为诊断抗dsDNA抗体阴性的系统性红斑狼疮的有效指标。

3D打印导板技术联合多次去旋转治疗重度僵硬性脊柱侧凸

背景:近年来,随着3D打印技术的发展,使得外科手术走向个性化、精准化。3D打印导板技术可实现术前规划、术中导航,使得外科手术更加精准。临床中重度僵硬性脊柱侧弯矫形术中仍面临置钉准确性不高导致螺钉松动甚至引起神经并发症的问题,现有关于3D打印导板技术指导重度僵硬性脊柱侧弯术中置钉的研究不多。目的:评价3D打印导向模板技术联合后路多次去旋转治疗重度僵硬性脊柱侧凸的临床效果。方法:回顾性分析3D打印导向模板椎弓根螺钉置入后联合施行后路多次转棒去旋转技术治疗重度脊柱侧凸6例患者的临床资料,男3例,女3例,手术时年龄15-23岁,平均(18.17±3.49)岁。分析术后2周和术后18个月时脊柱侧弯相关参数的变化,进行统计学分析。结果与结论:(1)手术时间280-540 min,平均(340.83±102.20)min,术中出血量1000-4000 mL,平均(2000.00±1073.70)mL,固定节段9-14个椎体,平均(11.83±1.72)个椎体,矫形过程中未出现螺钉松动;(2)所有患者均获得随访,术后2周全脊柱正侧位片显示冠状位主弯的cobb角、冠状面C_(7)铅垂线和S1正中线的距离、矢状面C_(7)铅垂线和S1后缘的距离、顶椎偏移、胸椎后凸角、腰椎前凸角均获得明显矫正,主弯的cobb角平均矫正率62.22%,术后18个月随访各参数较术后2周无明显变化,矫形效果满意,无感染和内固定断裂;(3)围术期切口延迟愈合1例,经过换药处理瘢痕愈合,未出现神经并发症;(4)结果表明3D打印导向模板结合后路多次转棒去旋转技术治疗重度僵硬性脊柱侧凸畸形安全有效,矫形效果满意。

Comparison and Selection of Arch-Rib Construction Schemes for Continuous Beam arch Composite Bridge of High Speed Railway

The paper summarizes the four different construction schemes based on engineering cases for the arch rib construction of continuous beam-arch composite bridges for high-speed railways.These methods include in-situ assembly,segmental lifting,incremental launching and longitudinal moving,and vertical rotation.The temporary structural designs,process methods,and technological equipment for each construction scheme are described in detail.The advantages and disadvantages of each scheme and its application scope under various conditions are analyzed,and opinions and suggestions for guiding the application of each scheme are proposed.The comparison and selection analyses show that the four arch rib construction schemes have certain applicability under different conditions such as bridge site status,bridge span,and construction environment.With the continuous increase of bridge span and progress of construction technological equipment,the arch rib construction technology is developing towards the overall erection direction.This leads to more obvious technical advantages of the segmental lifting method,incremental launching and longitudinal moving method,and vertical rotation method.Therefore,it is necessary to select the best construction scheme according to the construction status and technical conditions during application.

肋骨环抱器治疗肋骨骨折的有效性研究及有限元建模分析

目的探讨肋骨环抱器治疗肋骨骨折的疗效,采用有限元分析评估肋骨环抱器内固定治疗肋骨骨折的应力分布。方法回顾性研究分析2019年1月—2022年12月北京市大兴区人民医院胸外血管外科收治的137例多发肋骨骨折患者资料,男性106例,女性31例;年龄25~62岁,平均37.0岁;道路交通伤64例,高处坠落伤34例,摔伤12例,钝器击打伤16例,其他11例。根据治疗方式,应用传统外固定非手术治疗的为传统组(62例),应用肋骨环抱器治疗的为环抱器组(75例)。比较两组患者机械通气时间、引流管拔管时间、下床活动时间、住院时间、骨折愈合时间、治疗前后VAS、止痛药物使用剂量、骨折愈合情况和围术期并发症发生情况。应用Mimics软件对人体胸廓CT数据进行三维重建,建立正常肋骨和肋骨环抱器内固定后的骨折肋骨模型,应用Abaqus17.0软件进行有限元分析,模拟并计算三种不同载荷下肋骨最大位移和应力响应情况。结果与传统组比较,环抱器组机械通气时间[(6.1±1.3)d vs.(10.1±2.7)d]、引流管拔管时间[(1.75±0.32)d vs.(3.73±0.67)d]、下床活动时间[(7.84±2.40)h vs.(12.58±3.03)h]、住院时间[(6.70±1.43)d vs.(10.05±3.66)d]、骨折愈合时间[(22.92±8.40)d vs.(35.73±9.95)d]均显著缩短,治疗后VAS[(3.3±0.9)分vs.(5.2±1.2)分]显著降低,止痛药物使用剂量[(63.1±19.5)mg vs.(103.3±32.4)mg]显著减少,P均<0.001。评价骨折愈合效果,环抱器组优良率(97.3%,73/75)显著高于传统组(77.4%,48/62)。环抱器组肺部感染、肺不张和胸廓畸形并发生率均明显低于传统组(P<0.05)。有限元分析结果显示,肋骨骨折应用肋骨环抱器固定后其可承受较大的压力,骨折的最大移位比正常肋骨小,断面间隙值<0.01 mm。结论肋骨环抱器内固定治疗肋骨骨折疗效显著。有限元分析也从生物力学角度证实肋骨环抱器具有良好的固定性能,能保证固定后肋骨的稳定性。

人工智能软件检测胸部CT肋骨骨折的效能探讨

目的探讨评价人工智能(artificial intelligence,AI)软件辅助放射科医师在胸部CT图像检测肋骨骨折的应用效能。方法选取因胸部外伤行急诊胸部CT检查的患者301例。将6位放射科医师分为低年资组(≤5年)和高年资组(≥10年)对CT图像阅片;1个月后,医师+AI软件联合进行第2次阅片。采用卡方检验比较不同组间检测肋骨骨折敏感度的差异。配对样本t检验比较结合AI前后医师诊断时间是否有统计学意义。结果低年资组+AI、高年资组+AI结合阅片在全部肋骨骨折、错位型、隐匿型肋骨骨折的检测敏感度均优于医师单独阅片,差异有统计学意义(P<0.001)。应用AI阅片后,高低年资组医师的阅片时间均明显缩短,差异有统计学意义(P<0.001)。结论AI软件辅助诊断有助于放射科医师提高肋骨骨折检测效能,优化诊断流程并有效减少诊断时间。

人工智能对医师诊断新鲜肋骨骨折的应用价值

目的 探讨人工智能(AI)软件对放射科住院医师、主治医师在新鲜肋骨骨折病灶检出率的差异及其应用AI前后的一致性评价,评估应用AI后各级医师诊断新鲜肋骨骨折效能的提高情况。方法 收集因急性胸部外伤行胸部CT扫描病例300例,其中确诊为肋骨骨折的152例病例。将6位医师分为住院医师组和主治医师组两组,3人/组,对随机分配的300例CT图像独立阅片。在间隔为4周的洗脱期后,医师结合AI第2次阅片。采用卡方检验比较两组医师对新鲜肋骨骨折病灶及不同类型病灶检出率的差异,并评价各组应用AI前后的一致性、敏感度、特异度差异。结果 应用AI后住院医师、主治医师对所有新鲜肋骨骨折、完全性骨折、不完全性骨折的检出率均高于医师单独阅片,差异有统计学意义(P<0.001)。住院医师+AI、主治医师+AI对全部肋骨骨折、不完全性骨折的Kappa值与Phi系数均明显提高,不完全性骨折提高幅度最显著。住院医师+AI、主治医师+AI检出新鲜肋骨骨折敏感度与住院医师、主治医师单独阅片的差异有统计学意义(P<0.001),特异度的差异无统计学意义。结论 AI可有效提高不同级别医师对新鲜肋骨骨折的检出效能,并提高不同级别医师之间的一致性、敏感度。

大倾角钢箱提篮拱桥总体设计

考虑施工技术、经济性和景观效果等方面,陕西蔡家坡渭河特大桥主桥采用(35+210+35) m大倾角钢箱提篮拱桥。该桥采用摩擦摆和环向钢丝绳阻尼支座综合减隔震约束体系,以降低结构的地震响应。拱肋为单室等宽钢箱截面,采用主、副拱肋2条悬链线,主、副拱肋共面,设计为横向内倾20°的大倾角,在提高桥梁景观效果的同时,又有效提高了结构的整体稳定性;拱肋设钢-混结合段连接拱脚与混凝土拱座。桥面系采用自重较轻的正交异性钢桥面板结构。吊杆采用抗拉强度1 860 MPa的环氧柔性钢绞线。基础采用Φ2.5 m的钻孔灌注群桩,以抵抗软弱地质条件下荷载的竖向及水平作用力。该桥总体采用先梁后拱的施工方案。整体及局部有限元分析结果表明,桥梁结构力学性能均满足规范要求,设计安全可靠。

便携式高频超声在肋骨骨折诊断中的价值

目的探讨便携式高频超声在肋骨骨折诊断中的价值。方法回顾性分析68例172处有肋骨骨折和18例54处无肋骨骨折的胸部创伤患者的便携式高频超声、胸部DR、64排双源CT检查结果,比较三者的肋骨骨折诊断效能。结果便携式高频超声共诊断出肋骨骨折160处,误漏诊16处;胸部DR诊断出肋骨骨折130处,误漏诊54处;64排双源CT检查出肋骨骨折165处,误漏诊10处。便携式高频超声(AUROC=0.93)和64排双源CT检查(AUROC=0.95)对肋骨骨折的诊断效能相近(P>0.05),均高于胸部DR检查(AUROC=0.77),差异有统计学意义(P<0.05)。结论便携式高频超声对肋骨骨折有很高诊断价值,是肋骨骨折的重要检查方法,在没有CT的医院可替代CT作为肋骨骨折的常规检查方法。

多层螺旋CT后处理技术及体检信息对肋骨骨折诊断的应用效果

目的探讨多层螺旋CT(MSCT)后处理技术及体检信息对肋骨骨折(RF)诊断的应用效果.方法随机选取2019-01至2023-12武警山东总队医院收治的400例RF患者的MSCT资料,其中受伤7d内初检且受伤3~8周内复检的97例患者纳入本研究.初检分为A、B组,由2名影像科高年资医师独立诊断,A组医师了解患者体格检查信息后,对容积再现(VR)、最大密度投影(MIP)、多平面重建(MPR)、曲面重建(CPR)进行针对性诊断;B组医师对以上项目进行盲诊.以复检结果为标准,统计分析常规横断面(TRA)图像和后处理技术诊断各类型RF的效能.结果初检时,A组不同方式诊断Ⅰ、Ⅱ、Ⅲ型RF的准确率均高于B组,其中Ⅰ、Ⅲ型RF的诊断准确率比较,差异有统计学意义(P<0.05),MPR、CPR方式诊断Ⅰ、Ⅲ型RF的准确率显著高于其他方式(P<0.05);不同方式诊断Ⅱ型RF的准确率差异均无统计学意义,但MPR后处理技术可视性强、诊断平均用时短于其他方式,差异有统计学意义(P<0.05);Ⅳ型RF在初检时未检出,88例均在复检时检出,其中MIP方式诊断准确率明显高于其他方式,差异有统计学意义(P<0.05).结论MSCT后处理技术可用于不同类型RF的诊断,不但诊断准确率高,且诊断用时较短,可明显提高诊断RF的效率.

AI对急诊外伤肋骨骨折诊断效能的应用研究

目的探讨CT不同重建算法图像对人工智能(AI)辅助肋骨骨折检测效能的影响及AI辅助诊断系统对放射科住院医师诊断急诊外伤肋骨骨折诊断效能的影响。方法收集急诊胸部外伤病史的患者50例,所有患者均利用256层螺旋CT进行胸部CT成像,使用Standard、Lung、Bone和Soft 4种不同kernel重建算法进行图像重建,计算并比较AI在不同重建算法胸部CT图像下对肋骨骨折识别灵敏度、特异度及准确度的差异。结果AI在Standard、Lung、Bone和Soft 4种算法下对骨折检出的灵敏度分别为75.74%、86.63%、89.60%和69.31%,Lung和Bone算法下AI对肋骨骨折检出的灵敏度高于Standard和Soft(P<0.05)。AI在Standard、Lung、Bone和Soft 4种算法下对骨折检出的特异度分别为93.88%、93.17%、93.78%和94.18%,4种算法比较差异无统计学意义(P>0.05)。AI在4种算法下的准确度分别为90.82%、92.07%,93.07%和89.98%,4种算法比较差异有统计学意义(P<0.05)。放射科住院医师不使用AI和使用AI诊断肋骨骨折的灵敏度分别为82.18%、96.53%,特异度分别为95.08%、94.78%,准确度分别为92.90%、95.08%,使用AI后对肋骨骨折诊断的灵敏度及准确度均明显提高(P<0.05),而特异度比较差异无统计学意义(P>0.05)。放射科住院医师不使用AI诊断所用的时间为(240.79±63.20)s,使用AI所用的时间为(105.26±57.20)s,两个时间比较差异有统计学意义(P<0.05)。结论放射科住院医师利用AI能够明显缩短急诊外伤肋骨骨折诊断所用时间,提高工作效率,而且能够提高其对于急诊外伤肋骨骨折诊断的准确性。AI在帮助放射科住院医师更准确、更快速识别肋骨骨折中具有重要的价值。

超声引导下竖脊肌平面阻滞对多发肋骨骨折患者术后早期呼吸功能的影响

目的探讨超声引导下竖脊肌平面阻滞(ESPB)对多发肋骨骨折(MRFs)患者术后早期呼吸功能和炎性因子的影响。方法选择2019年2月至2021年12月择期行多发肋骨骨折手术患者58例,男42例,女16例,年龄18~64岁,BMI 18.5~30.0 kg/m^(2),ASAⅠ或Ⅱ级。采用随机数字表法将患者分为两组:ESPB联合全身麻醉组(E组)和单纯全身麻醉组(G组),每组29例。E组于麻醉诱导后在侧卧位下实施超声引导下ESPB,给予0.5%罗哌卡因0.4 ml/kg。记录麻醉诱导前、出PACU时、术后24、48 h的用力肺活量(FVC)、动脉血气分析、静息和咳嗽时VAS疼痛评分。记录术后0~24 h、24~48 h的PCIA有效按压次数和补救镇痛情况。记录麻醉诱导前、术后24、48 h的IL-6和TNF-α浓度。结果与G组比较,E组出PACU时、术后24、48 h的FVC明显增大(P<0.05),PaCO_(2)、静息和咳嗽时VAS疼痛评分明显降低(P<0.05)。与G组比较,E组术后0~24 h、24~48 h的PCIA有效按压次数和补救镇痛率明显降低(P<0.05)。与G组比较,E组术后24、48 h的IL-6和TNF-α浓度明显降低(P<0.05)。结论超声引导下ESPB可为MRFs患者提供良好的术后镇痛,促进术后早期呼吸功能的恢复。

加强筋位置对半穿甲战斗部侵彻多层钢靶性能影响研究

为了研究加强筋位置对半穿甲战斗部侵彻多层钢靶性能的影响,通过试验及数值仿真,研究了加强筋在弹体轴向不同位置处的2种半穿甲战斗部,以一定速度(710 m/s)、着角(20°)侵彻8层钢靶的弹道偏转、弹孔尺寸、余速的差异。研究结果表明:加强筋位置由弹尖向质心位置逼近时弹道偏转角减小、弹孔长轴减小、穿甲能力提升;弹道偏转角增量与靶间距呈正相关关系;弹道偏转角、侵彻余速、弹头侵蚀量及弹孔仿真结果与试验实测值最大偏差为8.82%,仿真与试验结果符合较好。研究结果可为半穿甲战斗部方案设计提供参考。