Effects of Tightening Torque on Dynamic Characteristics of Low Pressure Rotors Connected by a Spline Coupling

A rotor dynamic model is built up for investigating the effects of tightening torque on dynamic characteristics of low pressure rotors connected by a spline coupling.The experimental rotor system is established using a fluted disk and a speed sensor which is applied in an actual aero engine for speed measurement.Through simulating calculation and experiments,the effects of tightening torque on the dynamic characteristics of the rotor system connected by a spline coupling including critical speeds,vibration modes and unbalance responses are analyzed.The results show that when increasing the tightening torque,the first two critical speeds and the amplitudes of unbalance response gradually increase in varying degrees while the vibration modes are essentially unchanged.In addition,changing axial and circumferential positions of the mass unbalance can lead to various amplitudes of unbalance response and even the rates of change.

Microfocused Ultrasound for Nonablative Skin and Subdermal Tightening to the Periorbitum and Body Sites: Preliminary Report on Eighty-Two Patients

Lax crepey skin is a major unsightly finding throughout the face and body that occurs from chronological aging and environmental photodamage. Surgical lifting procedures are unable to induce sufficient neocollagenesis and also associated with visible scars, risks and recovery time. In this preliminary report, non-invasive delivery of microfocused ultrasonic thermal coagulation points at two levels of the dermis outside the orbital rims was effective in reduction of crepey, wrinkled and sagging skin for about 1 ? years in nineteen treated patients. Matched Orientation Mirror Imaging produced an average brow height elevation of 1 - 2 mm. Microfocused thermal coagulation points at multiple tissue levels also induced tissue tightening and reduction of crepey wrinkled skin in the décolletage, brachium, periumbilicus, inner thigh and knees. Investigator and Subject Global Aesthetic Improvement Scale graded responses that correlated to the severity of the degree of crepiness and laxity. Pain management during the procedure included the use of infiltration of local anesthesia. No permanent adverse events were observed. Further innovations in the current technology are needed for more effective and safer delivery of energy to improve the appearance of crepey and lax tissue in the head, neck and body.

The Effect of Extract of Oak Gall for Vaginal Tightening and Rejuvenation in Women with Vaginal Relaxation

Background and Objectives: The Quercus (oak) fruit and especially the internal layer of the fruit (jaft) is rich in tannin (polyphenolic compound) and due to its astringent effects on the smooth muscles, we decided to evaluate this effect of extract of Oak Gall for vaginal tightening and rejuvenation in women with vaginal relaxation. Methods: This double blind clinical trial was performed on women with vaginal relaxation at Asali Hospital in Khorramabad from May to October 2012 and was candidate for colporrhaphy due to different types of pelvic organ prolapse. Sampling method was done on nonprobability basis according to the number of patients referred to clinic. Using blocked random allocation method, the participants were divided into 4 groups of 30 patients (three intervention group and one control group) who were age-matched. Then, an extract of Oak Gall in specified concentrations (10 - 15 and 20 grams in 1.5%, 2% and 2.5% jells) were administered to each intervention group. Finally, the obtained data were analyzed with Chi-square, Pearson, Fisher’s exact test and ANOVA using SPSS software version 19. Results: A total of 120 patients entered into the study with mean age of 36 ± 5.4 years. The evaluation of mean scores showed that sense of sexual satisfaction and orgasm, sense of vaginal tightness during intercourse, sense of vaginal lubrication and loss of vaginal dryness was significantly improved in patients in intervention group. Also other parameters including urinary incontinence, sense of vaginal mass exit, lack of orgasm, sense of air outflow during intercourse, sense of calmness after sex and loss of libido were significantly reduced in the group of patients who received jell 2.5% compared to other groups (P Conclusion: Our findings show that using topical jell of Oak Gall not only is associated with contracting effects, but also improves vaginal lubrication and reduces its dryness. Regarding the lack of previous studies in this field and considering some limitations of this study, we suggest that Oak Gall to be used for management of women with vaginal relaxation.

Non-Excisional Face and Neck Tightening Using a Novel Subdermal Radiofrequency Thermo-Coaugulative Device

42 patients with broad age and ethnic demographics where treated with a novel, non-excisional, minimally invasive device to coagulate a very thin layer of sub-dermal septo-fascial fat, denature the deep reticular dermis and tighten the skin and sub-dermal matrix of connective tissue. The detailed treatment protocol and results are presented. Patients were observed for up to 6 month following the procedure. No major side effects were observed. The aesthetic outcome of this non-excisional procedure includes improvement of the position and shape of the cheek, lower lid-cheek junction, jawline and neck. The overall aesthetic results deliver a noticeable and impressive tightening of the soft-tissue and may be compared with a conservative, small excisional procedure. The authors propose this versatile device and treatment as a non-excisional, moderate facial rejuvenation procedure on its own, or as an adjunct to open procedures performed simultaneously, or as a simplified treatment for secondary skin laxity in combination with a lift procedure.

A Clinical and Histological Study of Radiofrequency-Assisted Liposuction (RFAL) Mediated Skin Tightening and Cellulite Improvement <br>——RFAL for Skin Tightening

Background: A novel Radiofrequency-Assisted Liposuction (RFAL) technology was evaluated clinically. Parallel original histological studies were conducted to substantiate the technology’s efficacy in skin tightening, and cellulite improvement. Methods: BodyTiteTM system, utilizing the RFAL technology, was used for treating patients on abdomen, hips, flanks and arms. Clinical results were measured on 53 patients up to 6 months follow-up. Histological and biochemical studies were conducted on 10 donors by using a unique GREDECO model of skin fragments cultured under survival conditions. Fragments from RFAL treated and control areas were examined immediately and after 10 days in culture, representing long-term results. Skin fragments from patients with cellulite were also examined. Results: Gradual improvement in circumference reduction (3.9 - 4.9 cm) and linear contraction (8% - 38%) was observed until the third month. These results stabilized at 6 months. No adverse events were recorded. Results were graded as excellent by most patients, including the satisfaction from minimal pain, bleeding, and downtime. Histological analysis of skin fragments immediately following RFAL treatment showed hypodermal coagulation of fat and blood vessels, and structural changes in dermal fibers. After 20 days in culture, fibroblast fibers metabolism was stimulated. Histological changes following cellulite treatment were also noted. Conclusions: The novel RFAL technology offers immediate skin tightening effect that is stable over time. The histological results correlated with the clinical observations of circumference reduction and skin tightening, as expressed by tissue fibers modulation. Moreover, RFAL offers an effective treatment for cellulite by formation of a thick collagen band at the dermal-hypodermal junction.

The Effect of Tightening on the Corrosion Properties of the PVD Layers on Magnesium AZ91D Alloy

The corrosive properties of PVD TiN-Ti-Al type composite titanium nitride layer with titanium and aluminium sub-layers system on the AZ91D magnesium alloy and its sub-layers were investigated by using polarization method and impedance spectroscopy, specifically, in terms of the hydrothermal tightening effect. The aim was to explain the mechanisms which contribute to high anticorrosive properties obtained by hydrothermal tightening. It was stated that the hydrothermal treatment changes the surface topography of the examined layers, most probably due to the formation of a continuous titanium oxides film. Tightening significantly modifies the corrosion resistance of the particular component sub-layers of the TiN-Ti-Al layer which exhibits optimum electrochemical parameters. It was shown that the increase of the electrochemical parameters is controlled by tightening of the outside titanium nitride layer, whereas the aluminium sub-layer plays a critical role in creating proper conditions for the hydrothermal tightening of titanium nitride.

Peri-Orbital Non-Invasive and Painless Skin Tightening-Safe and Highly Effective Use of Multisource Radio-Frequency Treatment Platform

The periorbital area is the third highest-ranking area for cosmetic surgery. However, surgery in this area presents a number of difficulties and safety concerns. First generation Monopolar RF treatments in this area were usually associated with considerable pain and long downtime. In the present clinical study, we used the iFine handpiece of the EndyMed PRO, multi-source phase-controlled radiofrequency (RF) for Non-invasive, pain free, skin rejuvenation of the periorbital area. The study included eleven (11) subjects, treated for periorbital signs of aging (iFine handpiece, EndyMed PRO platform, EndyMed Medical, Caesarea, Israel). The degree of clinical improvement was assessed by the global aesthetic improvement scale (GAIS) and subjects satisfaction by post treatment questionnaires. 91% of patients showed good to excellent improvement as a result of the treatment. Subjects satisfaction showed that 55% of patients reported that they were very satisfied, 45% were satisfied while none were dissatisfied. There were no incidences of infections, scarring, hypopigmentation, or any other serious complications.

Facial Tightening Following a Single Acoustic Wave Treatment Using Focused and Radial Acoustic Waves

Background: Acoustic wave has been used for many medical purposes, and although it is widely applied in cosmetic procedures, it has not been conducted for facial rejuvenation and tightening. Acoustic wave has been proven to penetrate deeper than subcutaneous tissue, independent of skin color, and to be beneficial for skin tightening and body contouring. Objective: To evaluate the effectiveness of a single acoustic wave treatment session using unique focused and radial acoustic waves for facial tightening. Participants: Sixty Asian patients were treated between the years 2016 and 2018. The single acoustic wave treatment session consists of focused long planar acoustic pulses thought to have an effect on cells and their metabolism resulting in an increased release of fat, and radial short acoustic pulses thought to have an effect on tissues activating blood and lymphatic flow. Patients did not undergo any form of medical aesthetic treatment during the study. Measurements: Digital photographs and three-dimensional imaging were used to evaluate the results. Results: Objective assessments with digital photographs and superimposed three-dimensional color images showed preferable facial tightening effects and marked volumetric reduction on the lower one-third of the face. These results were obtained without the edematous reactions observed in laser and radiofrequency therapies, and were sustained up to 12 months. All of the patients reported satisfaction with the results and convenience of the procedure. Complications were minor and transitory, consisting of a slight tingly sensation to the teeth during the treatment, and mild erythema resolving within 5 hours. Side effects were not observed. Conclusions: The advantages of the single acoustic wave treatment are the high potency of facial tightening effects, reduction of discomfort and side effects. Taken together, these characteristics facilitate the ability to give repeated treatments and provide an alternative or adjunct treatment for patients with improved results.

Tightening Ties

ChinAfrica： The Tanzam Railway is a symbol of Sino-Tanzanian friendship. What＇s your opinion on the development of the bilateral relations now？Abdulrahaman A. Shimbo： Yes indeed, the ＂Tanzania-Zambia Railway,＂ famously known as the TAZARA, is the most iconic symbol of our two countries＇ unwavering and close brotherly relations, It is truly a remarkable example of China＇s selfless act toward its friends, at a time when China itself had fewer economic, technological and military capacities.

角钢塔螺栓的紧固控制技术

针对角钢塔螺栓紧固作业需求,研究了一种轻量化、扭矩可准确控制的电动扳手.为了解决轻量化问题,提出了一种自抗扰控制器与滑模观测器融合算法,实现了无扭矩传感器的电动扳手扭矩参数估计与控制.首先,将自抗扰控制器引进扭矩环、速度环,在对其总扰动量进行估计的同时得到角加速度的估计值,然后将该角加速度值作为二阶滑模观测器的输入进行紧固扭矩值的估计,解决了二阶滑模观测器中变量的导数值难以获得的问题.仿真和实验结果表明,与传统PID控制器、滑模控制器相比,所提方法可实现扭矩的准确估计,具有扭矩调节时间短,超调小的特点.

八角型螺栓球节点研发、配件标准编制和工程应用

高强度螺栓的“假拧”是螺栓球节点空间网格结构普遍存在的安全隐患及事故诱因之一。为此,提出一种空间网格结构用八角型螺栓球节点,并对其进行系统研发。介绍了该节点的组成、安装机理和主要优点。基于对该节点的研发成果,编制发布了其关键配件的产品标准——《螺栓球节点用八角型高强度螺栓和套筒》(T/CSCS011—2021),对该标准的主要编制思路和要点进行了介绍。最后介绍了该节点在珠海机场二号航站楼指廊屋盖网架中的应用情况,对采用该节点的网架和采用焊接球节点的网架进行了对比分析,结果表明,两种节点形式网架的力学性能和设计指标基本相当,八角型螺栓球节点网架的经济性更好。上述标准和节点的首次工程应用为该节点的推广奠定了良好基础。

高压自紧式聚酰亚胺垫片密封性能影响因素分析及结构优化

为了解决液体火箭发动机在异常工况下的密封失效问题,建立了发动机充气阀阀芯密封结构的有限元模型,分析了密封结构参数、加工误差及卡滞偏斜对充气阀阀芯密封性能的影响,并进行了试验验证。结果表明:综合考虑可加工性、密封效果,圆阀座是充气阀的首选结构;在不同圆角半径下,圆角半径在0.35~0.45 mm范围内使用效果最佳;平面度偏差及卡滞偏斜在0~0.07 mm范围内对密封效果和使用寿命几乎没有影响。本研究可为航天军工用高精密密封的设计和优化提供参考,有助于提高我国高精密密封的技术水平。

双螺母防松螺栓拧紧过程的理论与仿真研究

工程中双螺母防松是一种常见的螺栓连接防松形式。为研究双螺母螺栓拧紧过程中的力学性能,考虑螺纹柔性的影响,建立了双螺母螺栓连接的力学模型,对螺纹的受力进行了分析,推导并给出了螺栓杆轴力和螺纹表面接触应力的计算方法,研究了螺纹接触应力的分布规律,以及上下螺母拧紧力矩配比对螺纹接触状态的影响,建立了螺栓预紧力与上下螺母拧紧力矩的关系,分析对比了螺栓规格、螺母厚度配比对螺栓杆轴力分布、接触应力的影响规律。建立了双螺母螺栓的精细化有限元模型,并将仿真结果与理论结果进行了对比验证,结果发现该文推导给出的螺栓杆轴力计算方法与有限元结果吻合很好。

一种3D生物束带阴道紧缩术的临床应用

目的介绍一种3D生物束带阴道紧缩术,探讨其临床应用、疗效及手术安全性。方法统计我院2021年6月-2023年6月利用一种3D生物束带完成的阴道紧缩术患者86例的临床资料,其中患者包括漏尿43例,反复阴道炎22例,性生活不适21例,均伴有不同程度的外阴外观不满意。观察术后漏尿、反复阴道炎及性生活不适改善情况;随访术后性生活满意度、阴道松弛改善、阴道湿润度等指标;明确手术安全性、术后并发症。结果87例中43例漏尿痊愈38例,22例反复阴道炎痊愈18例,21例性不适消失20例;盆底肌总评分术前为(47.49±3.58)分,术后(75.55±5.52)分。统计学结果显示手术前后漏尿、阴道炎、性不适及盆底肌评分具有显著差异性(P﹤0.001)。性生活满意度、阴道变紧、性欲望、阴道湿润度及阴道外观满意度达93%~100%。术后显示小阴唇闭拢,会阴体饱满;手术失血量平均5 mL,术后出现轻微并发症2例。结论这种3D生物束带阴道紧缩术通过加强阴道后壁及会阴体实现治疗轻中度压力性尿失禁,减少反复性阴道炎及性生活不适,增加女性的外阴美观及自信心。手术安全、创伤小、并发症少及疗效满意。

改良全程阴道紧缩术的临床疗效评价

目的探讨改良全程阴道紧缩术治疗中重度阴道松弛(VLS)患者的治疗疗效。方法选取2020年1月至2022年12月于郑州大学第三附属医院医疗美容科收治并成功随访的53例中重度VLS并实施改良全程阴道紧缩术的患者。比较患者手术相关指标、临床疗效和性功能改善情况。结果2例(3.77%)患者术后出现短暂的尿潴留,予以电刺激治疗后排尿顺畅,未再留置尿管;1例(1.89%)患者术后出现会阴切口少量渗血,压迫止血后好转;其余患者围手术期均无并发症发生。53例患者切口均为Ⅱ/甲级愈合,无血肿、感染及瘢痕增生等并发症。51例(96.23%)患者对外阴形态及阴道紧致程度满意;1例(1.89%)患者术后1个月有性生活史,术后2个月随访,阴道容2指松,对阴道紧致程度不满意;1例(1.89%)患者术后2个月阴道口黏膜稍有堆积,对外阴形态不满意;1例患者术后2个月出现性交痛,术后6个月自行好转;4例(7.55%)有阴道干涩的患者症状较术前有所缓解。7例(13.21%)有反复阴道瘙痒、分泌物增多等的患者症状较术前有明显改善;8例(15.09%)有性交疼痛的患者症状较术前明显改善。53例中重度VLS患者阴道动态压力值和FSFI-6评分在术后2个月、6个月和12个月与手术前比较时均显著改善,差异具有统计学意义(P<0.05),且术后2个月、6个月及12个月阴道动态压力值前后对比,差异无统计学意义(P>0.05)。结论改良全阴道紧缩术不仅关注了阴道的功能和外阴的形态,还考虑到了加强盆底的支持作用,符合VLS整体诊治和盆底整体功能恢复的需求,具有操作安全,并发症少的优势,并且可以增加性快感的优势,临床应用效果令人满意。

面对面角接触球轴承装置热力耦合仿真分析

在研究轴承时为了方便计算简化模型,一般将组合装置中的两个轴承简化成一个轴承进行分析,这样会带来一定的误差,因此这里分析了面对面球轴承组合装置中两个轴承的热特性耦合。这里首先分析了角接触球轴承的摩擦力矩,根据混合润滑机理,考虑了混合热阻影响,计算了轴承在发生摩擦时生成的热量,通过ANSYS的APDL命令流将进行参数化建模,建立了面对面轴承组合装置仿真模型,再利用APDL命令流循环计算出组合装置不同时刻下的温度场和在不同时刻温度场下的热膨胀诱导的力,从而分析出组合装置中的两个轴承预紧力和发热量的时变耦合特性。实验结果表明,这里模型与实验数据吻合,验证了本模型的正确性。

珠江口盆地白云凹陷古近系深层高变温背景下储层成岩作用与低渗致密化机制

珠江口盆地白云凹陷油气勘探逐渐从中-浅层韩江组-珠江组的常规储层转向深层-超深层珠海组-恩平组的低渗致密储层,特殊的高变地温地质背景使得储层成岩作用以及致密化机制与常规储层差别较大。综合运用铸体薄片鉴定、扫描电镜观察、物性测试、成岩过程重建和物性恢复等技术,系统分析了白云凹陷西北部低隆起-中部洼陷带古近系珠海组下段-恩平组砂岩储层的成岩过程及差异,结合构造演化背景、地层埋藏史和现今物性数据,研究了影响储层物性关系的主要因素以及储层致密化过程与机理。结果表明:珠海组下段-恩平组储层经历了较强的压实作用、2期碳酸盐胶结、3期硅质胶结和3期长石溶解作用。储层成岩作用过程中,地温梯度变化导致压实速率不同,经历不同开放-封闭体系的水-岩反应过程是不同区带物性差异的主要原因。压实作用是导致储层致密的主要因素,硅质胶结和碳酸盐胶结进一步增强了储层致密程度,溶解作用改善了储层物性。从低隆起到洼陷带,伴随地温梯度升高和埋藏深度增加,低隆起储层成岩阶段为中成岩A2期,斜坡带为中成岩B期,洼陷带为晚成岩期,成岩强度不断增加;成岩作用的差异使得储层物性演化显著不同。洼陷带储层在晚期烃类充注前已致密化,斜坡带储层在晚期烃类充注阶段逐渐致密,而低隆起区储层目前仍为低渗储层。斜坡带整体埋深小于5 km,且上覆地层具备良好封盖能力,是下部勘探的重点。

书夹型钢-混组合结构在桥梁加宽中的应用研究

为避免桥梁加宽时下部结构拓宽,减少新旧桥面纵向裂缝及铺装层损伤,提出一种以钢结构立柱及护栏、书夹式钢板、高强度螺栓为主要构件,超高性能混凝土(UHPC)为铺装层的书夹型钢-混组合结构进行桥梁加宽。为评估该组合结构在运营条件下的安全性,以厦门官浔溪大桥加宽工程为背景,通过实桥现场静载试验研究水平荷载作用下书夹型钢-混组合结构的力学性能,并与数值仿真结果进行对比,验证试验结果的可靠性。结果表明:实测结果与数值仿真结果吻合良好;书夹型钢-混组合结构关键部位荷载~位移曲线、荷载~应力曲线呈线性变化,钢结构最大拉应力约为材料屈服强度的75%,整体结构处于弹性工作阶段;螺栓预紧力有效减少了高强度螺栓的直剪作用,降低了剪切疲劳破坏风险;采用书夹型钢-混组合结构进行桥梁加宽可有效避免下部结构拓宽,改善新旧桥面纵向裂缝及铺装层损伤,具有较好的加宽效果。

钢板加固螺栓球节点力学性能试验研究

针对螺栓球节点高强螺栓漏拧、少拧的情况,实际工程中常采用焊接钢板加固螺栓球节点来保障螺栓球节点承载力。为探究钢板加固螺栓球节点的破坏形式及极限承载力规律,对三组高强螺栓拧入深度0.5d(d为螺栓直径)螺栓球节点采用钢板加固并进行受拉承载力试验。试验结果表明,钢板加固螺栓球节点虽能提高节点的承载力,但试件高强螺栓和钢板变形很难协调,共同受力不理想,易发生局部破坏。故对原有加固方法进行改进,并进行加固后螺栓球节点拉伸破坏试验。结果表明,改进后的钢板加固螺栓球节点力学性能得到很好的提升,可为螺栓节点加固提供保障。

开槽螺母-螺栓连接副拧紧特性研究

由于飞机飞行过程持续遭受振动载荷,设计中广泛采用具有自锁功能的开槽螺母-螺栓连接副以防螺栓的松动和夹紧力损失。研究开槽螺母-螺栓连接副的拧紧特性,对保证连接结构的力学性能、安全性和可靠性具有重要意义。对开槽螺母拧紧工艺开展了理论分析,修正了其夹紧力-拧紧力矩关系公式。试验研究了开槽螺母型号、被连接件材料、润滑条件以及重复拧紧次数等条件对拧紧特性的影响。研究结果表明,NASM14144开槽螺母相较于高度较低的NASM14145开槽螺母,预置力矩提升了125.9%,而扭矩系数稍有降低;饱和润滑方式能有效降低扭矩系数及其波动性,螺母-连接板贴合面润滑的效果次之;重复拧紧过程使得NASM14144螺母的预置力矩降低、扭矩系数明显升高,而NASM14145螺母的拧紧特性并未显著改变。