h an H-beam steel H形鋼條。 an H-Post H形電桿。 drop one's h's 不發(fā)h音〔如倫敦方言中把 hat 讀作'at 〕。 H hour 【軍事】發(fā)起攻擊的時(shí)間;特定軍事行動(dòng)開始的時(shí)刻。 = 【電學(xué)】 henry; 【化學(xué)】 hydrogen; 【物理學(xué)】磁場(chǎng)密度 (intensity of magnetic field), 地磁水平分量 (the horizontal component of terrestrial magnetism); 〔表示鉛筆芯硬度的符號(hào)〕= hard(ness); 〔俚語〕heroin. H1 = 【化學(xué)】protium. H1+ = 【物理學(xué)】proton. H2 = 【化學(xué)】deuterium. H3 = 【化學(xué)】tritium.
In the h - r diagram below , our sun is now in the main sequence 在以下的赫羅圖中,太陽正位于主序上。
From the two h - r diagrams below , we can also tell which cluster is older and which is younger 由以下兩幅赫羅圖中,我們可斷言右圖表示的星團(tuán)比較年老。
Before the interstellar cloud contracts , it was very cold and dim . thus , the cloud is represented by a point at the right in the h - r diagram 在星際云收縮之前,它非常冰冷,所以在這個(gè)階段,星際云會(huì)位于赫羅圖上一個(gè)極右的位置。
Upon contraction under its own gravity , the interstellar cloud heats up , and thus moving to the left in the diagram . note that the position of a star in the h - r diagram shows its physical properties , not its position in the sky 當(dāng)星際云收縮,它會(huì)變得越來越熱,而它在赫羅圖上的位置亦會(huì)向左移動(dòng)注意:恒星在赫羅圖上的位置顯示了它們的物理特性,而非其在天空的位置。
We expect stars with short life span are already dead . when we plot the stars of a cluster in the h - r diagram , we see the more massive stars , which are stars in the upper left , have already evolved off the main sequence 換句話說,星團(tuán)內(nèi)壽命短的星應(yīng)該已經(jīng)死去,當(dāng)我們把星團(tuán)內(nèi)的星以赫羅圖的形式繪畫出來時(shí),我們發(fā)覺位于圖中左上角的大質(zhì)量恒星果然已經(jīng)步入死亡階段,離開了主序星的行列。