鎂合金超級鋼鐵

機械工程與市民日常生活息息相關，例如用來製造火箭的鎂合金，現時亦會用來造手提電腦的外殼。今年「裘槎優秀科研者獎」得獎者、香港大學機械工程系教授黃明欣研究高性能金屬材料，他將運用相關獎項的資助，減低對稀土元素的依賴。

超級鋼鐵材料，創造了合金材料「強塑性」及「強韌性」組合的兩項世界紀錄，以及發明全球首個表面可殺滅新冠病毒的不銹鋼，成果已授權給企業用於生產日常用品。

黃表示，通常鋼的密度約為每立方厘米7.85克，紙的密度則約為每立方厘米1.2克，而鎂合金的密度僅約每立方厘米1.74克，所以鎂合金的特點是十分輕便。他舉例指，內地長征五號火箭運用很多鎂合金，令火箭重量十分輕盈，有助升空。不過，目前鎂合金主要以稀土混合鎂金屬製成，成本高，稀土亦屬罕有資源，不符合可持續發展方針。他又指，生產稀土會釋放有毒物質，推測每生產1,000克的稀土，就會釋放大約2,000克的有毒物質。他期望將鎂合金的材料的硬度提高約兩倍。

他和團隊利用泛函密度理論指導下的人工智能機器學習策略，以及位錯工程理論，尋找稀土的替代合金元素組合以進行鎂合金合成，並初步發現鈣（Ca）和銻（Sb）以及鉍（Bi）和銻這兩個非稀土合金元素組合，並製作出實驗成品。

黃明欣：可用於生物醫學領域

黃明欣表示，現階段以非稀土合金元素合成的鎂合金受壓強度有約250兆帕斯卡（MPa），未來的研究目標是提升到約400兆帕斯卡，與在工地用作建築的鋼筋強度一樣，同時保持10%的柔韌度，方便屈曲但不折斷，以及保持低密度和輕量的特性。除了工業用途外，他認為，以非稀土合金元素製成的鎂合金還可用在生物醫學領域，例如製作治療骨折時用的骨釘，可以自然溶解，免除再動手術將其移出的麻煩和痛苦，未來不排除把醫學應用也列入研究方向之中。

運用新穎「變形配分」（Deformed and Partitioned process）方法製成

yahoo

ppfocus

science

Metallic glass from MetroU

spacecraft application

留言

這個網誌中的熱門文章

CMOS sensor trends and astrophotography, from amateur astronomers perspective

Nowadays, even in low light conditions, digital camera can quality pictures with higher ISO, noise and hot pixels have been gradually reduced. Sony has introduced back illumination process for consumer market. Sony BSI sensors evolved from Exmor to now Exmor RS( stacked) technology. This stacked technology allows further chip size reduction, which has strong demands in smartphone camera market. Digital astrophotography is also benefited from such advances, utilising Back Side Illumination technology Exmor: Within the CMOS sensor, it outputs low-noise digital signals by "on-chip column AD conversion" and "dual noise reduction" to suppress noise in the first half of the process In low light conditions, when a wide aperture is desirable to collect as much light as possible. At apertures wider than f/2.0, back-illuminated Exmor R sensors are significantly more efficient at collecting light than conventional, front-illuminated sensor...

閱讀完整內容

ultrafast rendezvous to ISS

14 Oct 2020, being the first to use a new “ultrafast” rendezvous” scheme with the ISS. Following a flawless ascent to the correct orbit, Soyuz 2 .1a , Soyuz MS-17 caught up with the orbiting laboratory in only two orbits (three hours), halving the time it takes for crew to get to the Station. The three space travelers of the Soyuz MS-17 mission launched on a six-month mission the International Space Station. previous 3/4 orbit rendezvous: Soyuz MS-16 4 orbit rendezvous A three-orbit profile was deemed possible without major flight design changes after inauguration of the Soyuz 2-1A rocket that provides a much higher orbit injection accuracy than its predecessors and would allow the two correction maneuvers on Orbit #2 to be eliminated while the Automated Rendezvous Phase would still remain untouched. The deletion of the Orbit #2 maneuvers was expected to slightly tighten the already restrictive phase angle window from and upper limit of 30-35° to 25-28°...

閱讀完整內容

Scythians 斯泰基塞種西古提人

900 BC - 200 AD British museum Tomb of scythe prince, Buktarma valley, 1200 masl, Google map Herodotus 絲路上的帝國 Biblegeography 哥羅西書 3：11 在此並不分希利尼人、猶太人、受割禮的、未受割禮的、化外人、西古提人、為奴的、自主的．惟有基督是包括一切、又住在各人之內。塞種塞迦 saka 史記漢書西域傳：塞種 ctext 昔匈奴破大月氏，大月氏西君大夏，而塞王南君罽賓。塞種分散，往往為數國。自疏勒以西北，休循、捐毒之屬，皆故塞種也。匈奴列傳 Ctext ：塞王《史記》在《大宛列傳》與《匈奴列傳》中，詳細記錄了中亞至天山一帶的塞種（塞王、塞地）狀況。例如，文中記載了月氏西破走塞王，導致塞人南遷越過懸度（今帕米爾高原及克什米爾一帶） Baike Genetic history Genetics Nih griffin ? Scytho-Siberian world 塞迦 saka wiki Disappeared? Sarmatians （薩爾馬泰，奄蔡史記 , Aorsi ）and goths YouTube

閱讀完整內容

Hello!! It's Joseph

搜尋此網誌