液压胀接压力理论计算研究

本文结合蒸汽发生器管子管板胀接机构及材料特性,采用用简化的两端开口的套筒模型,对该产品液压胀接压力进行了计算和确定,为后续实施胀接工艺评定、产品胀接提供了理论基础和数据。     

核电高加热管的胀接工艺性探讨

在目前国内的部分核电的机组中，高压的加热前换热管都已经全部采用铁素体的不锈钢管，该不锈钢管与其他的不锈钢管材不一样，管材的脆性转变的温度比较高，并且对换热器胀接的质量产生了很大的影响。本篇文章主要从胀接的温度以及化学成分等方面讨论影响材料脆性的转变温度因素，通过模拟一些胀接的实验，验证此材料胀接的性能好坏，本篇文章讨论的内容为核电高加生产和制造提供了一定的参考。     

核电厂发电机空冷器新型堵漏工艺开发与应用

秦山核电一厂发电机空气冷却器发生过传热管大面积泄漏,堵管率超过设计裕量,为此开发了一种新型在线快速堵漏工艺并成功应用.在传热管内加装一根传热管,两根传热管之间为间隙配合,然后使用胀管工艺使两根传热管与管板胀接固定,最后使用耐海水专用防腐涂料进行管板密封.此方法在单根传热效率略微下降的基础上,最终达到了堵漏的目的,传热效...     

三通管水胀成型机控制系统设计应用

本文是针对三通管水胀机新型控制系统、新型工艺控制方法进行设计应用研究。此处采用FX系列可编程控制器对其进行控制,由PLC控制器、触摸屏和位移传感器,压力传感器,液压比例控制阀等组成的过程控制,相应开关量并联接入PLC的I/0点完成信号的逻辑控制通过合理的选择和设计提高了控制水平并大大改善了三通管胀型的工艺使得三通管水胀成型效率品质有了明显的提高     

核电厂蒸汽发生器管板厚度计算方法研究

核电厂蒸汽发生器管板厚度计算是压水堆一回路系统承压边界尺寸计算的关键。本文采用TEMA标准和ASME VIII-1标准对包括蒸汽发生器传热管节距、布管圆直径、管板外径、筒体连接段厚度等主要参数的变化对管板厚度计算的影响进行对比计算分析,研究蒸汽发生器管板厚度计算标准应用特点。     

基于高效换热器换热管失效原因分析及预防措施

高效换热器换热管在工业生产中广泛运用,其工作状况直接影响工业正常生产。利用宏观、微观观察,用X射线分析换热器换热管失效的原因,发现换热管的失效由多种原因造成,主要包括应力腐蚀、温度影响等。本文通过对失效换热管进行检查,分析高效换热器换热管失效原因,并在此基础上,提出预防高效换热器换热管失效的措施。     

核电高加管板管孔检验工装改进及创新

针对火电高压加热器管板钻孔后检验工装效率低的缺点,对某核电高压加热器管板钻孔后检验工装进行改进及创新,详细描述了新检验工装的原理及测量方法,改进后及创新的检验工装提高了检验效率,为某核电高压加热器管板孔垂直度与孔间距的质量检验提供了可靠的技术保障具有良好地经济效益和应用价值     

浅谈国内管壳式换热器发展

换热器是工业生产中最常用的设备,在不同工作条件下对换热器性能要求不同,它是冷热流体间传递热量的设备。一般国内换热器最为常用的是管壳式换热器,比如:浮头式换热器,固定管板式换热器,U形管式换热器等等。换热器主要有管板、壳体、换热管、折流板、拉杆、定距管、封头等组成。由于换热器结构比其他压力容器相对简单,所以其运用比较广泛。换热器在工、农业的各个领域应用十分广泛,在日常生活中传热设备也随处见,是不可缺少的工艺设备之一。随着研究的深入,工业应用取得了令人瞩目的成果。本文就换热器的换热形式以及近几年换热器的发展进行讨论。     

15CrMoR与12Cr1MoVG异种钢的焊接

在分析15CrMoR与12Cr1MoVG钢母材成分及焊接性能的基础上,根据异种钢接接头焊缝金属成分,选择相应焊接材料进行工艺试验,提出了改进的焊接措施,有效地防止了高压蒸汽管冷裂纹和其它焊接缺陷的产生。     

空调翅片式蒸发器换热效果对比分析

以空调翅片式蒸发器为研究对象,采用Ansys有限元分析软件,选用合适的传热模型和边界条件,模拟翅片表面的温度场和速度场。模拟及实验结果表明,蒸发器处于不同的气流组织结构中会相应地改变机组换热性能。对比分析实验结果可得增加导流板可以优化蒸发器的气流组织分布进而达到增强机组换热性能的目的。     

Tube gastrostomy in dogs

Tube gastrostomy was performed in 19 dogs over a period of 36 months. Indications for tube gastrostomy included non-oral feeding for the management of oesophageal injuries (nine cases) and dysphagia resulting from oral or pharyngeal trauma (two cases) and decompression and, or, gastropexy for gastric diseases including gastric dilatation volvulus (four cases), gastric outflow diseases (three cases) and gastric neoplasia (one case). All the tubes were placed surgically and left in situ for periods of up to 14 days. Feeding was by frequent bolus administration of a proprietary enteral food initially followed by homogenised commercial dog food. The tubes were readily managed and patency maintained in all cases. Gastric stomata granulated within three days of tube removal. Fourteen dogs recovered and returned to normal oral feeding while three died as the result of their presenting condition. A fourth was euthanased four months after surgery because of recurrence of a gastric malignancy. This review indicates that surgically placed tube gastrostomy is readily performed and is an effective means of providing non-oral alimentation and, or, gastric decompression.     

Minimally Invasive Inguinal Approach for Tube Cystostomy

Objective— To report a technique for tube cystostomy placement via a minimally invasive inguinal approach and outcome in 9 dogs and 6 cats with urinary tract obstruction or detrusor atony.
Study Design— Case series.
Animals— Dogs (n=9) and cats (6).
Methods— Medical records (January 2004–January 2008) of dogs and cats that had tube cystostomy via an inguinal approach were reviewed. Retrieved data included signalment, diagnosis, surgical technique, and complications. Access to the bladder was through a muscle splitting approach in the inguinal region with the cystostomy tube placed through a skin incision made several centimeters proximal to this incision and secured in the bladder by a purse string suture. Cystopexy during closure of the muscle layers ensured secure closure and minimized the likelihood of uroabdomen if tube dislodgment occurred.
Results— Cystostomy tubes were placed in 5 cats as an emergency procedure for treatment of acute urinary tract obstruction or urethral rupture, and as an elective procedure in 9 dogs and 1 cat. No complications occurred during cystostomy tube placement. Postprocedural complications were minor (peristomal irritation in 2 dogs with latex catheters, catheter laceration, premature removal) and only occurred when tubes were retained for >4 weeks. Urinary tract infection at catheter removal in 6 dogs resolved with antibiotic administration.
Conclusions— An inguinal approach for cystostomy tube placement facilitated rapid catheter placement into the bladder with minimal soft tissue dissection. Cystopexy during abdominal wall closure provided peritoneal protection should premature dislodgement of the cystostomy tube occur.
Clinical Relevance— An inguinal approach should be considered for rapid tube cystostomy particularly in metabolically compromised animals.     

Vital Aspects of Fallopian Tube Physiology in Pigs

This essay reviews four topical aspects of Fallopian tube physiology that bear on either successful fertilization or early development of the zygote. An initial focus is on glycoprotein secretions of the duct that accumulate as a viscous mucus in the caudal isthmus. Because this is the site of the pre‐ovulatory sperm reservoir, an involvement of the secretions is considered in: preventing uterine and ampullary tubal fluids from entering the functional sperm reservoir; removing residual male secretions from the sperm surface; deflecting spermatozoa towards endosalpingeal organelles and reducing flagellar beat before ovulation. The subtle prompting of flagellar movement with impending ovulation is examined in terms of potential reactivation mechanisms, with overall control attributed to increasing secretion of progesterone. The site of full capacitation and the acrosome reaction in a fertilizing spermatozoon is then debated, with strong arguments pointing to completion of these processes in the specific fluids at the ampullary‐isthmic junction. Finally, the synthetic activity of cumulus cells released at ovulation as a paracrine tissue in the Fallopian tube is highlighted with reference to steroid hormones, peptides and cytokines. Not only does the suspension of granulosa‐derived cells influence the process of fertilization, but also it may amplify oocyte or embryonic signals to the endosalpinx and ipsilateral ovary.     

Tube cystostomy in the dog and cat]

Prepubic tube cystostomy was performed in 10 dogs and one cat. Indications include urinary bypass following urethral trauma or surgery (six cases), following surgery for prostatic abscesses or cysts (four cases) and bladder atony secondary to urethral obstruction (one case). Tubes were left in situ for a minimum of seven days. All patients returned to normal micturition following tube removal. Urine leakage occurred for up to four days after tube removal by which time the stoma was granulating. Nosocomial infection was a consistent finding, but was controlled with antibiotic treatment following tube removal. Tube cystostomy was considered an effective means for diverting irritant urine from healing epithelium and thereby minimising the risk of urethral cicatrisation. It may also be indicated in the management of urinary retention as an alternative to repeated urethral catheterisation. This study indicates that tube cystostomy is readily performed, with few unexpected or serious complications.     

Endotracheal Tube Displacement During Cervical Manipulation in the Dog

A retrospective study was performed to identify positional changes of endotracheat tubes (ETT) during cervical spine radiography in 153 dogs. Three neck positions were identified: traction, hyperextension, and flexion. A properly placed ETT was defined as having the caudal tip of the tube located between the caudal half of the fourth cervical (C) vertebra (C₄) and the caudal half of C₇. In the traction position, before neck flexion and extension, the caudal tip of 13% of ETT were located caudal to C₇, and one tube was in the endobronchial position at the seventh thoracic (T) vertebra (T₇). In the hyperextended position, 60% of ETT moved cranially. The average distance moved was 0.6 vertebral spaces. In the flexed position, all ETT moved caudally. The average distance moved was 3.5 vertebral spaces, with 81.8% of ETT located caudal to C₇ and seven tubes in endobronchial positions. Endotracheal tube occlusion caused by kinking at the atlanto-occipital joint was seen in four dogs during flexion of the neck. Based on this study, ETT position should be monitored during cervical manipulation.     

黑龙江林蛙输卵管营养成份分析

本实验用日立８３５—５０氨基酸分析仪、岛津ＧＣ—９Ａ气相色谱仪、索氏脂肪提取器分别测定了黑龙江林蛙输卵管阴干制品中氨基酸、脂肪酸、脂肪的含量。测得氨基酸总和为５０．７９％（伊春）、４７．４８％（大兴安岭）；脂肪酸总和为２．４４６９ｍｇ／ｇ（伊春）、２．７９３１ｍｇ／ｇ（大兴安岭）；脂肪为３．４６％（伊春）、３．１１％（大兴安岭）。结果表明，黑龙江林蛙输卵管是一种高蛋白、低脂肪的滋补品且具有较高的药用价值。     

Esophagostomy Feeding Tube Use and Placement in Exotic Pets

Providing enteral nutrition to injured or ill exotic animal patients by means of assisted feedings minimizes catabolism and gastrointestinal morbidity associated with anorexia, while optimizing immune system and organ function, and providing nutritional precursors necessary for healing. When determining the nutritional needs of a debilitated animal, it is important to account for both metabolic rate and energy requirements. Providing enteral nutrition via a feeding tube utilizes the functional gastrointestinal tract in patients that cannot or will not eat. Additionally, administration of food through a feeding tube is significantly less stressful for patients than restraint and syringe feeding. Feeding tube placement should be considered in any animal where the stress associated with syringe feeding is likely to result in significant morbidity or when the need for an extended period of assisted feeding is required.     

Fertilization and Early Embryonic Development in the Porcine Fallopian Tube

Fertilization and early embryo development relies on a complex interplay between the Fallopian tube and the gametes before and after fertilization. Thereby the oviduct, as a dynamic reproductive organ, enables reception, transport and maturation of male and female gametes, their fusion, and supports early embryo development. This paper reviews current knowledge regarding physiological processes behind the transport of boar spermatozoa, their storage in and release from the functional sperm reservoir (SR), and of the interactions that newly ovulated oocytes play within the tube during their transport to the site of fertilization. Experimental evidence of an ovarian control on sperm release from the SR is highlighted. Furthermore, the impact of oviductal secretion on sperm capacitation, oocyte maturation, fertilization and early embryo development is stressed.