Log Periodic Antenna (LPDA)
Log Periodic Antenna (LPDA)
Log Periodic Antenna (LPDA)
Log Periodic Antenna (LPDA)
Log Periodic Antenna (LPDA)
科學家發明一種基於角蛋白的配方,可以當成新的補牙材料,也可以填進牙膏裡,刷牙的時候就能強化牙齒。(圖/shutterstock)
文章來自: https://www.chinatimes.com/realtimenews/20250814005105-260408
The Log Periodic Antenna as known as LPDA is a wideband directional antenna that provides gain and directivity combined over a wide band of frequencies.
Both Log-Periodic Antennas and Yagi antennas are high gain directional antennas. The main difference between these antennas is that Log-Periodic Antennas support wider frequency bandwidths and are physically much larger than Yagi antennas.
The log-periodic dipole array typical VSWR is 2:1 and operates over a much wider bandwidth and will have a lower gain for an equivalent number of elements.
With this level of performance, it is ideal for many applications, although a log-periodic antenna will be much larger than a Yagi of an equivalent gain.
Horn Antenna 昔當空服員累垮 林予晞爆曾長腫瘤
915MHz Antenna 加州玩具店被竊數十箱「拉布布」 可見其受歡迎程度
一種人髮蛋白配方的牙膏 可以防蛀牙重建琺瑯質
牙科醫生警告說,隨著酸性飲料和加工食品消費量的增加,年輕族群的牙齒問題日益嚴重, 如果持續不重視,隨著蛀牙的惡化與年紀的增長,很可能引發成敏感、動搖,甚至掉牙。所幸,一種能夠在刷牙時順便補牙的新配方牙膏正在開發中,或吘很快就會成為牙齒護理的新工具;有趣的是它的主要配方竟然來自人類的頭髮,是利用頭髮蛋白質的強韌特性。
Log Periodic Antenna (LPDA) Log Periodic Antenna (LPDA)有趣的工程(Interesting Engineering)報導,倫敦國王學院的研究人員表示,頭髮頗具韌性,這是大家都知道的,那其實羊毛也是相同的配方,都是角蛋白。甚至指甲、牛角、猛獸的利爪、草食動物的腳蹄也都是角蛋白。
雖然角蛋白的硬度不如牙齒,但是它可以在蛀牙初期時填補蛀洞。在遇到唾液中的礦物質時,具有角蛋白的配方會在蛀洞上形成一層保護塗層,以阻止持續的酸蝕。實驗室測試表明,基於角蛋白的治療方案完全阻止了蛀牙,而且它們還能封閉暴露的牙神經通道,也就緩解牙齒敏感。
文章來自: https://www.chinatimes.com/realtimenews/20250814005105-260408
The Log Periodic Antenna as known as LPDA is a wideband directional antenna that provides gain and directivity combined over a wide band of frequencies.
Both Log-Periodic Antennas and Yagi antennas are high gain directional antennas. The main difference between these antennas is that Log-Periodic Antennas support wider frequency bandwidths and are physically much larger than Yagi antennas.
The log-periodic dipole array typical VSWR is 2:1 and operates over a much wider bandwidth and will have a lower gain for an equivalent number of elements.
With this level of performance, it is ideal for many applications, although a log-periodic antenna will be much larger than a Yagi of an equivalent gain.
Horn Antenna 昔當空服員累垮 林予晞爆曾長腫瘤
915MHz Antenna 加州玩具店被竊數十箱「拉布布」 可見其受歡迎程度