نتایج جستجو برای: pulse doppler
تعداد نتایج: 134303 فیلتر نتایج به سال:
سابقه و هدف: به طور سنتی عملـکرد قلب برروی عملکرد سیستولیک متمرکز بود در حالی که فانکشن دیاستولیک در درجه دوم اهمیت قرار داشت. در سال های اخیر مشخص شده که عملکرد دیاستولیک نقش مهمی در مورتالیتی و موربیدیتی قلبی دارد. فشار خون سبب اختلال عملکرد سیستولیک و دیاستولیک بطن می شود که به علت افزایش پس بار می باشد. در این مطالعه عملکرد دیاستولیک بطن راست در افراد فشار خونی با استفاده از روش (ptd) pulse...
This paper explores how pulse-diverse modulation of an FSK-PSK modulated pulse train enhances exibility to shape the size and distribution of the pulse train's ambiguity volume on the Doppler-delay plane. Pulse-diverse modulation compresses each pulse in the pulse train di erently. Based on a priori information of the relative criticality of various Doppler-delay regions, (e.g., the presence of...
Objective- The purpose of this study was to investigate the feasibility of performing echocardiography in apparently healthy pigeons, and measurement of the quantitative cardiac indices using B-mode and Doppler techniques. Design- Experimental study Animals- Ten apparently healthy pigeons Procedures- Echocardi...
Objective- Analysis of the PSV (peak systolic velocity), EDV (end diastolic velocity) and RI (Resistant Index) in external ophthalmic and the long ciliary ophthalmic arteries in the cat by pulse Doppler. Design- Descriptive study Animals- 12 short haired “Tomcats” weighted about 3.9± 0.9 Kg no e general and optic disease in clinical, paraclinical and ophthalmoscopic examinations. Pr...
Recent advances have demonstrated the feasibility of molecular imaging using targeted microbubbles and ultrasound. One technical challenge is to selectively detect attached bubbles from those freely flowing bubbles and surrounding tissue. Pulse Inversion Doppler is an imaging technique enabling the selective detection of both static and moving ultrasound contrast agents: linear scatterers gener...
Doppler devices can provide clinically useful information about blood flow. This paper describes how a pulse-Doppler instrument has been linked to a B-scan machine so that flow patterns in any ultrasonically accessible vessel can be monitored from the skin surface. The same transducer is used for both modes of investigation to enable accurate and reliable positioning of the sample-volume. After...
Polyphase is a common class of pulse compression waveforms in the radar systems. Oppermann code is one of the used codes with polyphone pattern. After compression, this code has little tolerant against Doppler shift in addition to its high side lobe level. This indicates that the use of Oppermann code is an unsuitable scheme to radars applications. This paper shows that the use of amplitude wei...
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