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61.
激光脉冲激发的超声脉冲波形的理论研究 总被引：1，自引：0，他引：1
在激光热弹产生超声的研究中，对于产生超声的激光脉冲波形，大都是采取简化处理了的矩形脉冲或三角形脉冲，这样的处理虽然在计算上较易得出结论，但它与真实的高斯激光脉冲有较大的差别。为此笔者采用更接受于实际激光脉冲波形的梯形脉冲模型，应用热传导方程和Navier-stokes方程对半无限大介质中所激发的超声脉冲特性进行了计算研究，结果得出了比矩形脉冲更具有普遍性的结果，也与实验结果相符。 相似文献
62.
丁久香 《襄樊职业技术学院学报》2011,10(3):33-34
目的探讨彩色多普勒超声诊断宫外孕的特征性依据,提高宫外孕诊断的准确性。方法对临床怀疑异位妊娠患者行多途径（经阴道或腹部）彩色多普勒超声探查子宫附件区域,并与血人绒毛膜促性腺激素（HCG）检查结果比较,确诊宫外孕。结果 100例疑似宫外孕患者的超声检查中,5例因附件区未见异常包块未能确定。另95例均发现附件区包块,其中包块内实质性部分可检测到滋养血流信号57例,频谱为低阻力型;伴有不同程度的盆腹腔积液54例,双侧卵巢可同时显示85例。结论对疑似早期宫外孕的患者进行二维经阴经腹彩超检查,测量包块处滋养动脉血流频谱存在,同时测定血HCG阳性,可以早期诊断宫外孕。 相似文献
63.
郑伟花 《南阳师范学院学报》2011,10(9):31-35
介绍了无损检测中超声检测的发展,包括基于超声散斑所含界面的信息来测量界面位移的两种新方法即超声散斑相关法和超声散斑干涉法.并对这两种方法的理论及其相关的实验过程和数据处理作了综述.讨论了这两种方法适用的测量范围和条件,以及未来的发展趋势. 相似文献
64.
Floyd E. Bell III Francis H. Neuffer T. Robert Haddad James C. Epps Michael E. Kozik Brandon C. Warren 《Anatomical sciences education》2019,12(3):310-316
More emphasis is now being placed on active learning in medical education. Ultrasound is an active learning tool that can be used to supplement didactic instruction. This study describes a self-guided activity for learning floor of mouth ultrasound. Thirty-three first year medical students learned floor of mouth scan technique and ultrasound anatomy through a brief PowerPoint module. They subsequently performed the scan on a standardized patient. Each student was asked to label the floor of mouth muscles on the image he or she acquired. After the activity, the students were given a quiz on anatomic relationships of the floor of mouth. Perceptions about the activity were collected through a survey. All 33 students obtained a floor of mouth image within a three minute time limit. Twenty-four (73%) students were able to completely and accurately label the image in time. The mean score on the muscle relationships quiz was 93%. Overall perceptions were very positive with most students expressing a “high” or “very high” level of interest in incorporating similar self-guided activities within the curriculum. This study showed that it is feasible for students to learn scan technique and recognize relevant ultrasound anatomy in an independent fashion through a brief active learning module. Furthermore, the students found the activity enjoyable. The implication is that similar activities could be developed which would provide additional ways to incorporate active learning strategies. 相似文献
65.
崔结 《湖州师范学院学报》1998,(6)
在强碱条件下,用超声辐射并使用相转移催化剂,二卤降蒈与卤仿反应发生卤素交换.并对该反应的游离基反应历程作了初步探讨. 相似文献
66.
Ultrasonography is a noninvasive imaging modality, and modern ultrasound machines are portable, inexpensive (relative to other imaging modalities), and user friendly. The aim of this study was to explore student perceptions of the use of ultrasound to teach “living anatomy”. A module utilizing transthoracic echocardiography was developed and presented to undergraduate medical, science, and dental students at a time they were learning cardiac anatomy as part of their curriculum. Relevant cardiac anatomy was explored on a student volunteer and images were projected in real‐time to all students via an AV projection system. Students were asked to complete a questionnaire about the learning experience and were given the opportunity to provide open feedback. The students' evaluations of this learning experience were very positive. They agreed or strongly agreed that it was an effective way to teach anatomy (90% medical; 77% dental; 100% science) and that it was incorporated in a way that promoted reinforcement of the lecture material (83% medical; 76% dental; 100% science). They agreed or strongly agreed with statements that the experience was innovative (93% medical; 92% dental; 100% science) and stimulated interest in the subject matter (86% medical; 75% dental; 96% science), and that they would like to see more modules, exploring other anatomical sites, incorporated into the curricula (83% medical; 72% dental; 100% science). We believe that ultrasound could be a useful tool, in conjunction with traditional teaching methods, to reinforce the learning of anatomy of a variety of different undergraduate student groups. Anat Sci Educ. © 2010 American Association of Anatomists. 相似文献
67.
Kun ZHAO Jing ZHANG Tianhua XU Chuanxi YANG Liqing WENG Tingting WU Xiaoguang WU Jiaming MIAO Xiasheng GUO Juan TU Dong ZHANG Bin ZHOU Wei SUN Xiangqing KONG 《Journal of Zhejiang University. Science. B》2021,22(10):818
ObjectiveCardiac hypertrophy and fibrosis are major pathological manifestations observed in left ventricular remodeling induced by angiotensin II (AngII). Low-intensity pulsed ultrasound (LIPUS) has been reported to ameliorate cardiac dysfunction and myocardial fibrosis in myocardial infarction (MI) through mechano-transduction and its downstream pathways. In this study, we aimed to investigate whether LIPUS could exert a protective effect by ameliorating AngII-induced cardiac hypertrophy and fibrosis and if so, to further elucidate the underlying molecular mechanisms.MethodsWe used AngII to mimic animal and cell culture models of cardiac hypertrophy and fibrosis. LIPUS irradiation was applied in vivo for 20 min every 2 d from one week before mini-pump implantation to four weeks after mini-pump implantation, and in vitro for 20 min on each of two occasions 6 h apart. Cardiac hypertrophy and fibrosis levels were then evaluated by echocardiographic, histopathological, and molecular biological methods.ResultsOur results showed that LIPUS could ameliorate left ventricular remodeling in vivo and cardiac fibrosis in vitro by reducing AngII-induced release of inflammatory cytokines, but the protective effects on cardiac hypertrophy were limited in vitro. Given that LIPUS increased the expression of caveolin-1 in response to mechanical stimulation, we inhibited caveolin-1 activity with pyrazolopyrimidine 2 (pp2) in vivo and in vitro. LIPUS-induced downregulation of inflammation was reversed and the anti-fibrotic effects of LIPUS were absent.ConclusionsThese results indicated that LIPUS could ameliorate AngII-induced cardiac fibrosis by alleviating inflammation via a caveolin-1-dependent pathway, providing new insights for the development of novel therapeutic apparatus in clinical practice. 相似文献
68.
Steven Obst Luke Heales Zachary Hrelja Prashneveet Ishri Johanna Wesche Lee Barber 《Journal of sports sciences》2019,37(16):1874-1883
This study examined the effect of diamond deloading tape on medial gastrocnemius (MG) muscle behaviour during exercise in healthy adults (n = 27). A randomised cross-over trial assessed the effect of tape (no-tape, sham-tape and deload-tape) on ankle and MG fascicle kinematics during three heel raise-lower exercises [double leg (DL), single leg (SL) and loaded single leg (LSL)]. There was no effect of tape on standing fascicle length (FL) or pennation angle (PA), or ankle or knee joint angle. There was a significant effect of tape on ankle kinematics for all exercises. Both the deload-tape and sham-tape resulted in less ankle plantar flexion but had no effect on dorsiflexion. There was a significant effect of tape on FL change for the SL and LSL exercise. Compared to no-tape, the deload-tape resulted in less fascicle shortening during ankle plantar flexion, and more fascicle lengthening during ankle dorsiflexion. For the LSL exercise, deload-tape caused MG fascicles to operate at longer lengths, for a given joint angle. Diamond taping, with or without added tension, has only a small effect on ankle and MG fascicle kinematics during the heel raise-lower exercise. With the exception of the LSL exercise, both tape conditions resulted in similar changes in the FL-angle relations. 相似文献
69.
管道内粉体的气力输运广泛存在于化工、食品加工、电力、冶金和医药等工业生产过程中.通过对粉体颗粒的速度、体积分数和粒度等关键参数进行在线测量, 可实现过程优化控制, 提高生产效率和产品质量,降低能耗.本文从声散射理论模型出发,数值模拟并拟合出超声衰减系数和声速随粉体体积分数的变化关系.设计中心频率为30 kHz的一体式超声波探针,在杭州某水泥厂输运管道进行管内不同深度测点水泥生料粉体浓度的在线测量,分别以衰减和声速方法获得管内粉体沿径向的体积分数分布. 相似文献
70.
目的：评估体外冲击波联合肌内效贴治疗跟腱腱病的临床疗效。方法：选取20名研究对象，随机分成单纯冲击波治疗（ESWT）组和体外冲击波联合肌内效贴共同治疗（ESWT+KT）组，每组各10人。分别于治疗前、治疗后1个月、治疗后3个月对所有患者采用VISA-A跟腱腱病评分表进行评分。在治疗后3个月时采用6点Likert评分表对患者主观满意度进行评价，在治疗前和治疗后3个月用高频彩超对比跟腱纤维形态变化。结果：（1）VISA-A评分：ESWT、ESWT+KT两组治疗后VISA-A评分与其治疗前比较存在显著的统计学差异（P＜0.01）；ESWT+KT组治疗后各时间点与治疗前的VISA-A评分差值与ESWT组相比存在统计学差异（P＜0.05）。（2） 6点Likert评分：ESWT+KT组的患者满意率为100%，高于ESWT组（80%）。（3）高频彩超：ESWT、ESWT+KT两组治疗后的跟腱肿胀比治疗前都有缓解，且ESWT+KT组的肿胀改善程度优于ESWT组。结论：体外冲击波治疗跟腱腱病和联合肌内效贴共同治疗跟腱腱病都能够改善症状，患者满意程度高，且联合治疗组的疗效要优于单独治疗组。 相似文献