نتایج جستجو برای: ultralight high voltage

تعداد نتایج: 2134435  

Maryam Ramazani Mohamad Ali Shamsinejad, Reza Zare

In this paper, a DC-DC resonant converter with high voltage gain and small size is studied. To reduce the size and weight of this converter, the operating frequency should be as high as possible. In this research, the frequency changes from 120 to 200 kHz. Due to the high operating frequency, it is necessary to reduce the switching losses using soft switching methods. Resonant converters are su...

Maryam Ramazani Mohamad Ali Shamsinejad, Reza Zare

In this paper, a DC-DC resonant converter with high voltage gain and small size is studied. To reduce the size and weight of this converter, the operating frequency should be as high as possible. In this research, the frequency changes from 120 to 200 kHz. Due to the high operating frequency, it is necessary to reduce the switching losses using soft switching methods. Resonant converters are su...

2017
Johanne Mattie Jaimie Borisoff William C. Miller Borna Noureddin

An ultralight manual wheelchair that allows users to independently adjust rear seat height and backrest angle during normal everyday usage was recently commercialized. Prior research has been performed on wheelchair tilt, recline, and seat elevation use in the community, however no such research has been done on this new class of manual ultralight wheelchair with "on the fly" adjustments. The o...

2002
Hsin-yi Liu Rosemarie Cooper Rory A. Cooper

Previous studies found that select titanium ultralight rigid wheelchairs (TURWs) had fewer equivalent cycles and less value than select aluminum ultralight folding wheelchairs (AUFWs). The causes of premature failure of TURWs were not clear because the TURWs had different frame material and design than the AUFWs. We tested 12 aluminum ultralight rigid wheelchairs (AURWs) with similar frame desi...

Journal: :Journal of rehabilitation research and development 2008
Hsin-yi Liu Rory A Cooper Jonathan Pearlman Rosemarie Cooper Samuel Connor

Comfortable propulsion and support, light weight, and small dimensions are important features that help preserve upper-limb integrity of manual wheelchair users and improve accessibility. The titanium wheelchair is a product developed in response to these goals, but none of the test results of titanium wheelchairs had been disclosed before this study was performed. We hypothesized that these ti...

Journal: :The International Conference on Electrical Engineering 2010

Journal: :Science 2014
Xiaoyu Zheng Howon Lee Todd H Weisgraber Maxim Shusteff Joshua DeOtte Eric B Duoss Joshua D Kuntz Monika M Biener Qi Ge Julie A Jackson Sergei O Kucheyev Nicholas X Fang Christopher M Spadaccini

The mechanical properties of ordinary materials degrade substantially with reduced density because their structural elements bend under applied load. We report a class of microarchitected materials that maintain a nearly constant stiffness per unit mass density, even at ultralow density. This performance derives from a network of nearly isotropic microscale unit cells with high structural conne...

Journal: :Scientific Reports 2015

Journal: :Journal of rehabilitation research and development 2010
Hsin-yi Liu Jonathan Pearlman Rosemarie Cooper Eun-kyoung Hong Hongwu Wang Benjamin Salatin Rory A Cooper

Previous studies found that select titanium ultralight rigid wheelchairs (TURWs) had fewer equivalent cycles and less value than select aluminum ultralight folding wheelchairs (AUFWs). The causes of premature failure of TURWs were not clear because the TURWs had different frame material and design than the AUFWs. We tested 12 aluminum ultralight rigid wheelchairs (AURWs) with similar frame desi...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تهران 1379

در رساله حاضر ابتدا پلی اتیلن(ldpe) به دو روش سیلانی و پراکسیدی شبکه ای گردید که پارامترهای الکتریکی نظیر ثابت ، اتلاف دی الکتریک و استحکام شکست xlpe حاصل حاکی از مناسب بودن آمیزه برای عایق کابلهای با ولتاژ ضعیف و متوسط بود. به منظور بهبود خواص مکانیکی و استحکام شکست ، ldpe را با کوپلیمرهای اتیلنی نظیر اتیلن متیل اکریلات و اتیلن وینیل استات در دستگاه رول میل و برابندر اختلاط و سپس شبکه گردید که...

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