L形脉动热管电池包的传热性能数值研究

随着化石能源逐渐枯竭,新能源汽车成为主流交通工具.其核心部件——锂电池因其发热特性使汽车安全性难以保障.研究汽车锂电池热管理问题最终要解决电池包温度问题,对锂电池工作原理、发热机理进行模拟研究,通过传热学、流体力学等知识对锂电池建模.在ANSYS17.2中进行单体电池的网格划分及仿真分析,在1~3C的放电倍率下对L形脉动热管电池包的传热性能进行数值分析.结果表明,发热率随着C-rate的增加而增大,且电池环境温度的升高也会导致发热量的增加.其发热率范围为10~30 W.结果显示,通过对L型热管和板式锂离子电池构成的电池包进行仿真计算,在25℃冷却水条件和1~3C的电流条件下,电池包的平均温度保持在50℃以下,最高温度55℃,能够充分保证电池的正常工作温度.与其他散热方式相比,L形脉动热管在电池热管理系统中的散热性能最好.

不锈钢三通管脉动液压成形工艺参数优化

为获得不锈钢三通管脉动液压成形的最佳工艺参数,首先通过有限元方法研究了脉动加载条件下振幅和频率对零件成形性的影响规律。然后,结合响应面法,采用Box-Behnken方案进行了设计,建立了响应模型并研究了成形过程。以振幅、频率和轴向进给量为设计变量,目标件的最大减薄量和成形后总高度为响应量。结果表明,在一定范围内,大脉动加载振幅和小频率有助于改善三通管的成形性。响应面优化结果表明,在振幅为5 MPa、频率为0.8 Hz和轴向进给量为70 mm的组合下,可使零件成形总高度达到97.6 mm,最大减薄率控制在20%以内。试验获得零件的实际成形总高度为95 mm,最大减薄率为19.76%,试验结果与数值模拟吻合良好,且无明显缺陷,验证了响应面模型的准确性,并获得了最佳成形工艺参数。

圆柱形环状脉动热管烧干特性

当前各个领域对高效、高均温性的散热需求日益提高,脉动热管以其传热效率优异、加热方式灵活、结构简单等优势,成为合适、有效的散热元件。本文提出并设计了一种圆柱形环状脉动热管,并通过实验研究了圆柱形环状脉动热管的烧干特性。实验选用无水乙醇、HFE-7200为工质,在90°倾角条件下,对30%、70%充液率的脉动热管进行了加热功率为100~200W的实验测试;在30%充液率条件下,对30°、45°、70°安装角度的脉动热管进行了加热功率为20~100W的实验测试,研究了圆柱形环状脉动热管在不同弯头处的烧干特性。研究结果表明:倾角越大,圆柱形环状脉动热管在弯头处达到烧干时所需要的加热功率越大。当工质为HFE-7200,倾角分别为30°、45°、70°时,圆柱形环状脉动热管4个弯头处发生烧干状态的功率均为100W。

三峡库区香溪河段典型滑坡变形特征分析

本文从坡形采集入手,对三峡库区香溪河段蓄水后发生变形的滑坡进行归纳统计。统计表明,近水库岸坡为凸形的滑坡更容易发生变形。对香溪河段典型滑坡进行了长期地表位移监测,获得八字门滑坡和白家包滑坡的变形曲线为台阶状,耿家坪滑坡的变形曲线为脉动形。近库水微地貌为凸岸,滑体物质为老滑坡堆积物的滑坡变形曲线为台阶状,变形具积累性;近库水微地貌为凹岸,滑体物质为崩塌堆积物的滑坡变形曲线为脉动形,变形具“弹性”。

新型液压成形技术的研究进展

针对我国航空航天、汽车及核电等关键领域对精密零部件的迫切需求,以及目前液压成形技术应用中遇到的常见问题和缺陷,提出研发针对异形空心零件的脉动液压成形技术,和适用于复杂曲面薄壁板类零件的高能率冲击液压成形技术。分别从技术原理、成形机制、工艺设备和应用领域等方面进行了阐述和介绍。研究结果表明,两种新型液压成形技术能够充分发挥控形与控性一体化的优势,避免成形过程中的材料失稳和产品缺陷,显著提高管材和板材的成形能力和成形质量,未来有望在汽车和航空领域得到更为广泛的应用。

Mechanism of anti-arterial thrombosis of Dahuangzhecong Fang screened by Ti-Al intermetallic compound porous material

The mechanism of antithrombotic of Dahuangzhechong Fang separated and purified by Ti-Al intermetallic compound porous material (TAICPM) was researched. Dahuangzhechong Fang, which was isolated and screened by TAICPM, was used to oral rats. At the end of study, their blood and thrombus were collected. The results show that TAICPM with the pore size of 1-5 μm can screen Dahuangzhechong Fang well. Dahuangzhechong Fang can increase 6-keto-PGF1α, lower content of TXD2 and platelet. Dahuangzhechong Fang has good effect to resist arterial thrombosis.

Pharmacokinetics of Native r-SAK in Rabbit's Femoral Artery Thrombosis Model

Objective: To study the pharmacokinetics of native r SAK in rabbit's femoral artery thrombosis model, the “lytic circle' method was used to determine plasma levels of r SAK. Methods: Thirty New Zealand rabbits were randomly assigned to the control (saline 10 ml, 30 min), r SAK low dose (0.25 mg/kg, 30 min), medial dose (0.50 mg/kg, 30 min), high dose (1.00 mg/kg, 30 min), single bolus (0.50 mg/kg, 2 min) and conjunctive therapy (initiated with heparin 200 U/kg, followed by infusion of r SAK 0.50 mg/kg for 30 min, and subsequently infused heparin 50 U/(kg·h) to endpoint) groups. The right femoral artery thrombosis model in rabbit was made by balloon injury, then the thrombolytic agents were infused through parallel ear vein and the blood samples were collected pre thrombolysis and at different time post thrombolysis to determine the plasma levels of r SAK by “lytic circle' method, the plasma levels of r SAK were processed by pharmacokinetic computing procedure to fit the model. Results: The plasma levels of r SAK and the diameters of lytic circles showed a pretty good linear correlation under the scope of 2.0×10 4 2.0×10 6 U/L, and the averaged recycle rate was (96.05±11.35)%(RSD =±11.82%).All peak concentration time in each infusion group was 30 min, and the peak concentrations positively correlated with the doses administrated in infusion groups(r=0.999 98, P <0.000 1). In single bolus group, Peak concentration time was 2 min, and the peak concentration reached (5.16±1.02) mg/L, which was significant higher than that in the same dose r SAK infusion group ( P <0.01). In conjunctive therapy group, the peak concentration showed no significant difference from that in the same dose r SAK infusion group ( P >0.05). The plasma levels of r SAK fit in two compartment model as processed by pharmacokinetic computing procedure in each group. Conclusion: The “lytic circle' method is a simple, practical and reliable method to determine the plasma level of r SAK, and the pharmacokinetics of native r SAK infusion fits in two compartment model in rabbit's femoral artery thrombosis model.

Dynamic Response of Stepped Beams Under Impulsive Loading

Aim To analyze dynamic failure of aerospace strutures subjected lateral impulsive loading. Methods Structures were modeled as rigid-perfectly plastic free-free stepped beams. Basic equations of motion un set up for analysis. Results Final pat deformation and rigid motion solutions were determined for a uniform impulsive loading. The critical rupture conditions for a space shuttle and a missile were obtained. Conclusion Failure is possible for aerospace structures under a uniform impulsive loading, but it is mere difficult in space.

The application of ultrasound in the management of cerebral arteriovenous malformation

Ultrasound is used in the diagnosis, treatment and follow-up of cerebral arteriovenous malformation （AVM）. Several parameters including flow velocity, flow volume, resistance index, pulsatility index, vasomotor reactivity and their influencing factors are reviewed. The applications of ultrasound in the preoperative evaluation, intraoperative monitor and postoperative follow-up of AVM, are summarized. Although some limits exist, ultrasound can provide more reliable information about AVM, if lesions are classified according to their characteristics, compared in different conditions between preoperation and postoperation, feeding and non-feeding side, patients and healthy adults, and if ultrasound method is combined with other examinations and different developed ultrasound techniques. With the appearance and development of new ultrasound technique, its application will be wider in management of AVM..

Gastric angiodysplasia in a hereditary hemorrhagic telangiectasia type 2 patient

Hereditary hemorrhagic telangiectasia(HHT)is a rare autosomal-dominantly inherited disease that occurs in approximately one in 5000 to 8000 people.Clinical diagnosis of HHT is made when a person presents three of the following four criteria:family history,recurrent nosebleeds,mucocutaneous telangiectasis,and arteriovenous malformations(AVM)in the brain,lung,liver and gastrointestinal(GI)tract.Although epistaxis is themost common presenting symptom,AVMs affecting the lungs,brain and GI tract provoke a more serious outcome.Heterozygous mutations in endoglin,activin receptor-like kinase 1(ACVRL1;ALK1),and SMAD4,the genes involved in the transforming growth factor-βfamily signaling cascade,cause HHT.We report here the case of a 63 year-old male patient who presented melena and GI bleeding episodes,proven to be caused by bleeding from multiple gastric angiodysplasia.Esophagogastroduodenoscopy revealed multiple angiodysplasia throughout the stomach.Endoscopic argon plasma coagulation was performed to control bleeding from a gastric angiodysplasia.The patient has been admitted several times with episodes of hemoptysis and hematochezia.One year ago,the patient was hospitalized due to right-sided weakness,which was caused by left basal ganglia hemorrhage as the part of HHT presentation.In family history,the patient's mother and elder sister had died,due to intracranial hemorrhage,and his eldest son has been suffered from recurrent epistaxis for 20 years.A genetic study revealed a mutation in exon 3 of ALK1(c.199C>T;p.Arg67Trp)in the proband and his eldest son presenting epistaxis.

Analysis of pressure pulsation mechanism and dynamic characteristics of axial piston pump

The pressure pulsation of axial piston pump is not only an important cause of rotation speed fluctuation,vibration noise and output stability of the hydraulic system,but also the main information source for obtaining fault information.Hydraulic system is characterized by strong noise interference,which leads to low signal-to-noise ratio(SNR)of detection signals.Therefore,it is necessary to dig deep into the system operating state information carried by pressure signals.Firstly,based on flow loss mechanism of the plunger pump,the mapping relationship between flow pulsation and pressure pulsation is analyzed.After that,the pressure signal is filtered and reconstructed based on standard Gabor transform.Finally,according to the time-domain waveform morphology of pressure signal,four characteristic indicators are proposed to analyze the characteristics of pressure fluctuations under different working conditions.The experimental results show that the standard Gabor transform can accurately extract high-order harmonics and phase frequencies of the signal.The reconstructed time-domain waveform of pressure pulsation of the axial piston pump contains a wealth of operating status information,and the characteristics of pulsation changes under various working conditions can provide a new theoretical basis and a method support for fault diagnosis and health assessment of hydraulic pumps,motors and key components.

Clinical Observation on Shu Xin Yi Mai Capsules for Prevention of Recurrent Stricture after Coronary Artery Introducing Treatment

Shu Xin Yi Mai Capsules (舒心益脉胶囊) combined with western medicine was used in the routine treatment of 22 cases who successfully received coronary artery introducing therapy (Chinese-western medicine group),and the results was compared with the 26 cases treated routinely with simple western medicine in the control group (western medicine group).It was found that both the recurrence rate of angina pectoris and the incidence rate of recurrent stricture in the Chinese-western medicine group were significantly lower than that in the control group (both P<0.05).There was no significant difference between the two groups in expression of platelet activating molecules CD62P (a-granular membrane protein),CD63 (lysosome intact membrane protein) and CD41 (glucoprotein IIb) before the treatment,but with a significant difference after the treatment (P<0.05).

Cutting-balloon angioplasty before drug-eluting stent implantation for the treatment of severely calcified coronary lesions

Background Severely calcified coronary lesions respond poorly to balloon angioplasty, resulting in incomplete and asymmetrical stent expansion. Therefore, adequate plaque modification prior to drug-eluting stent （DES） implantation is the key for calcified lesion treat- ment. This study was to evaluate the safety and efficacy of cutting balloon angioplasty for severely calcified coronary lesions. Methods Ninety-two consecutive patients with severely calcified lesions （defined as calcium arc 〉 180% calcium length ratio 〉 0.5） treated with bal- loon dilatation before DES implantation were randomly divided into two groups based on the balloon type： 45 patients in the conventional balloon angioplasty （BA） group and 47 patients in the cutting balloon angioplasty （CB） group. Seven cases in BA group did not satisfactorily achieve dilatation and were transferred into the CB group. Intravascular ultrasound （IVUS） was performed before balloon dilatation and after stent implantation to obtain qualitative and quantitative lesion characteristics and evaluate the stent, including minimum lumen cross-sectional area （CSA）, calcified arc and length, minimum stent CSA, stent apposition, stent symmetry, stent expansion, vessel dissection, and branch vessel jail. In-hospital, 1-month, and 6-month major adverse cardiac events （MACE） were reported. Results There were no statistical differences in clinical characteristics between the two groups, including calcium arc （222.2° ± 22.2° vs. 235.0° ± 22.1 °, p=0.570）, calcium length ratio （0.67 ± 0.06 vs. 0.77± 0.05, P = 0.130）, and minimum lumen CSA before PCI （2.59 ±0.08 mm2 vs. 2.52 ± 0.08 mm2, P = 0.550）. After stent implantation, the final minimum stent CSA （6.26 ± 0.40 mm2 vs. 5.03 ± 0.33 mm2; P = 0.031） and acute lumen gain （3.74 ±0.38 mm2 w. 2.44 ± 0.29 mm2, P = 0.015） were significantly larger ila the CB group than that of the BA group. There were not statis tically differences in stent expansion, stent symmetry, incomplete stent apposition, vessel dissection and branch vessel jail between two groups. The 30-day and 6-month MACE rates were also not different. Conclusions Cutting balloon angioplasty before DES implantation in severely calcified lesions appears to be more efficacies including significantly larger final stent CSA and larger acute lumen gain, without increasing complications during operations and the MACE rate in 6-month.

Superior mesenteric artery syndrome in a diabetic patient with acute weight loss

Superior mesenteric artery(SMA)syndrome is an un- common disease resulting compression of the third portion of the duodenum from the superior mesenteric artery.This disease shares many common manifestations with diabetic gastroparesis,including postprandial fullness,nausea,vomiting,and bloating.Therefore,it is often overlooked in diabetic patients.Here,we report a 41-year-old man with poorly controlled diabetic mellitus who developed SMA syndrome due to rapid weight loss. The diagnosis was confirmed by computed tomography and an upper gastrointestinal series.His condition improved after parenteral nutrient,strict sugar control, and gradual weight gain.

Clinical features and treatment options for mitral regurgitation in elderly inpatients

Objective To summarize clinical characteristics and treatment strategy of Chinese elderly mitral regurgitation （MR） inpatients under the current guidelines, and to identify factors related to treatment options in them. Methods A single center retrospective study was conducted in which patients hospitalized in Fuwai hospital from May ist of 2014 to April 30 of 2015 with moderate to severe MR assessed by transthoraeic echocardiography were enrolled consecutively （n = 1741）. Patients 〉 60 years old were grouped as elderly group （n = 680） and patients 〈 60 years were grouped as control group （n = 1061）. The elderly group was categorized into two subgroups based on surgical status. Results The mean age of the elderly group was 66.98 i 5.94 years. The most common reason of MR in elderly group was degenerative MR （41.18%）. Atherosclerotic risk factors such as hypertension, diabetes or hyperlipidaemia were more commonly observed in elderly group than the control group （45.44% vs. 25.17%, P 〈 0.001; 19.56% vs. 8.48%, P 〈 0.001; 35.29% vs. 19.51%, P 〈 0.001）. Elderly group had higher Enroscore Ⅱ score （5.54 ± 2.42 vs. 3.15 ± 1.66）, greater left ventricular end diastolic diameter （LVEDD） （57.72±12.3 vs. 57.33 ± 10.19 ram） and a lower surgery rate （54.71% vs. 63.91%）; P 〈 0.05. Age, left ventricular ejection fraction （LVEF）, regurgitation grade, Eu- roScore-Ⅱ high risk stratification and having diabetes were identified as factors associated with therapy decisions in elderly MR patients. Conclusions Valve surgery was denied in 45.29% of elderly MR inpatients. Older age, impaired LVEF, lower regurgitation grade, Euro- Score-Ⅱ high risk stratification, and having diabetes were factors most significantly associated with surgery denial among elderly Chinese inpatients with MR.

ENDOVASCULAR EMBOLIZATION TREATMENT OF CEREBRAL ARTERIOVENOUS MALFORMATIONS（REPORT OF 54 CASES）

For further reaseach on endovascular embolization treatment of AVMs, 54 patients with AVMs treated with embolization were observed. It was found that embolization was an effective procedure for the treatment of AVMs. Combined treatment of AVMs with presurgical embolization and direct surgery could reduce the comphcations resulting from large and high flow AVMs with lone surgical removal.

Feasibility and short-term outcomes of transcatheter valve-in-valve implantation for failed aortic and mitral bioprosthesis-a single-center experience

Objectives Transcatheter valve-in-valve （VIV） implantation for failed bioprostheses has become an alternative to open surgery in those deemed high risk. The purpose of this study was to evaluate the effectiveness and outcomes of this emerging procedure. Methods Fourty VIV procedures were performed in 38 consecutive patients （mean age 70 ± 14 years and mean Logistic EuroScore 23.6 ± 15.5%） with severe aortic （n = 19） or mitral （n = 21） bioprosthetic valve dysfunction between 2014 and 2017. Bioprosthetic failure was secondary to stenosis in 11 （27.5%）, regurgitation in 19 （47.5%）, and combined in 10 （25.0%） bioprostheses. Clinical, echocardiographic, and procedural profiles were characterized, and the short-term results of the study patients were reported. Results Successful transfemoral （n = 15）, trans-subclavian （n = 1）, or transapical （n = 3） aortic VIV using either balloon-expandable valves （Edwards Sapien XT, n = 7） or self-expandable valves （Medtronic CoreValve, n = 12）; and transapical （n = 21） mitral VIV using either Edwards Sapien XT （n = 15） or me-chanically expandable valves （Boston Scientific Lotus, n = 6） were accomplished in all 40 VIV procedures. Implantation was successful with immediate restoration of satisfactory valve function in all patients. Five patients （13.2%） died at a median follow up of 9.3 months. Most of the 33 patients alive were in good functional status with good prosthetic valve performance. Conclusions Transcatheter VIV implantation is a feasible and safe option for the management of bioprosthetic valve failure. It may offer a less invasive alternative for those high-risk patients needing repeat valve replacement.

Significantly reduced function of T cells in patients with acute arterial thrombosis

Objectives To explore the intrinsic factors related to the pathogenesis of acute arterial thrombosis （AAT） and to elucidate the patho- genesis of AAT on the basis of differentially expressed genes. Methods Patients with acute myocardial infarction （AMI）, stable angina （SA） and healthy controls （n = 20 per group） were recruited, and the whole human genome microarray analysis was performed to detect the differentially expressed genes among these subjects. Results Patients with AMI had disease-specific gene expression pattern. Biological functional analysis showed the function of T cells was significantly reduced, the mitochondrial metabolism significantly decreased, the ion metabolism was abnormal, the cell apoptosis and inflammatory reaction increased, the phagocytosis elevated, the neutrophil-mediated immunity increased and the post-traumatic repair of cells and tissues increased in AMI patients. The biological function in SA group and healthy controis remained stable and was comparable. Conclusions The reduced function ofT cell gene models in AAT showed the dysfunction of the immune system. The pathogenesis of AAT may be related to the inflammatory reaction after arterial intima infection caused by potential pathogenic microorganisms.

Self-management of coronary heart disease in older patients after elective percutaneous transluminal coronary angioplasty

Objective To explore how older patients self-manage their coronary heart disease （CHD） aider undergoing elective percutaneous transluminal coronary angioplasty （PTCA）. Methods This mixed methods study used a sequential, explanatory design and recruited a convenience sample of patients （n = 93） approximately three months after elective PTCA. The study was conducted in two phases. Quantitative data collected in Phase 1 by means of a self-administered survey were subject to univariate and bivariate analysis. Phase 1 findings in- formed the purposive samplhag for Phase 2 where ten participants were selected from the original sample for an in-depth interview. Qualita- tive data were analysed using thematic analysis. This paper will primarily report the findings from a sub-group of older participants （n = 47） classified as 65 years of age or older. Results 78.7% （n = 37） of participants indicated that they would manage recurring angina symptoms by taking glyceryl trinitrate and 34% （n = 16） thought that resting would help. Regardless of the duration or severity of the symptoms 40.5% （n = 19） would call their general practitioner or an emergency ambulance for assistance during any recurrence of angina symptoms. Older participants weighed less （P = 0.02） and smoked less （P = 0.01） than their younger counterparts in the study. Age did not seem to affect PTCA patients＇ likelihood of altering dietary factors such as fruit, vegetable and saturated fat consumption （P = 0.237）. Conclusions The findings suggest that older people in the study were less likely to know how to correctly manage any recurring angina symptoms than their younger counterparts but they had fewer risk factors for CHD. Age was not a factor that influenced participants＇ likelihood to alter lifestyle factors.

COMBINED INTRAOPERATIVE ILIAC ARTERY STENTS AND FEMORO- POPLITEAL BYPASS FOR MULTILEVEL ATHEROSCLEROTIC OCCLUSIVE DISEASE

Objective. To review our preliminary experience and evaluate our early results of a combined intraoperative iliac angioplasty and stenting with infrainguinal revascularization in multilevel atherosclerotic occlusive disease. Methods. From July 1999 to April 2000, intraoperative iliac angioplasty and stenting combined with simultaneous femoro- popliteal bypass were performed on 12 lower extremities of 10 patients suffering from multilevel atherosclerotic occlusive disease. There were 8 men and 2 women, average 72 years. The indications for procedures included disabling claudication in 3 and rest pain in 7 patients. Results. Eleven iliac angioplasty and stent procedures combined with simultaneous 9 femoro- popliteal bypass and 3 femoro- femoral- popliteal bypass were performed in 12 limbs of 10 patients. Angioplasty and stent placement was technically successful in all patients. One contralateral femoral- popliteal bypass was failure after femorofemoral- popliteal bypass. There were no additional instances of procedural or postoperative morbidity or mortali- ty. Mean follow- up was 5 months (range 1～ 10 months). During the follow- up period, one femoro- infrapopliteal graft became occluded after 7 months and above- knee amputation was required. The cumulative primary patency rate of stented iliac arteries, femoro- femoral bypass grafts and femoro- popliteal bypass grafts were 100％ (11/11), 100％ (3/3) and 90.9％ (10/11) in the follow- up period, respectively. The amputation rate was 8.3％ (1/12). Conclusions. Intraoperative iliac artery PTA and stent placement can be safely and effectively performed simultaneously with infrainguinal revascularization for multilevel atherosclerotic occlusive disease by skilled vascular surgeon, using a portable C arm fluoroscopy in the operating room. Furthermore, iliac artery PTA and stenting was valuable adjunct to distal bypass either to improve inflow and outflow, or to reduce the extent of traditional surgical intervention, and also, any angioplasty and stenting- related complications can be immediately corrected as well.