首尾方向 的英文怎麼說
中文拼音 [shǒuwěifāngxiàng]
首尾方向
英文
cephalocaudal direction-
According to the guidline, two nd : yag lasers have been designed and set up, one is end - pumped by lower output power ld using a selfoc micro lens, and the other is end - pumped by high output power ld using a pair of lenses are designed, and the characteristics such as output power and power stabilization of both solid - state lasers are investigated. thirdly, when an empty liquid crystal cell is inserted in the cavity of the nd : yag laser pumped by high power ld, the laser can operates in single axial mode. finally, according to the relationship between the laser output power and the longnitudinal a ld - end - pumped nd : yag laser sensor for displacement measurement has been investigated theoretically and demonstrated experimently, the results indicate that when the mean radius of pumping inside the laser cavity is far less than that of the oscilating laser mode, the exponential of the output power is a gauss function of the longitudinal positon of focused spot of ld pumping beam, both the measurement range and the sensitivity are dependent on the incident pumping power, as the incident pumping power is increased, the measurement range is enlarged and the sensitivity is improve d
本文首先介紹了ld泵浦nd ： yag激光器的發展狀況、主要特性及其應用，從四能級速率方程出發，推導了ld泵浦nd ： yag激光器的閾值、輸出功率和斜效率的表達式，並簡述了激光器的工作原理、結構型式和倍頻方法；其次，以空間相關的速率方程為基礎，提出了ld端面泵浦nd ： yag激光器的設計方法，給出了一定泵浦耦合方式下，振蕩光模尺寸、最佳輸出耦合率、泵浦光模尺寸、泵浦光焦斑位置等參數的選取依據，以此為依據，設計了自聚焦透鏡耦合小功率ld泵浦nd ： yag激光器和透鏡組耦合高功率ld泵浦nd ： yag激光器，對激光器的輸出功率和功率穩定性等特性進行了實驗研究；再次，在帶尾纖輸出的高功率ld泵浦nd ： yag激光腔內插入一隻空液晶盒，觀察到了激光器以單縱模運轉；最後，根據泵浦光焦斑端面位置對激光輸出功率的影響規律，提出了ld端面泵浦nd ： yag激光位移傳感新方法，並進行了理論和實驗研究，研究結果表明：當激光晶體內泵浦光平均光斑半徑遠小於振西安理工大學碩士學位論文蕩光束腰半徑時，激光輸出功率的自然指數與泵浦光焦斑的縱向位置成高斯變化規律，測量范圍和靈敏度依賴于泵浦功率，隨著泵浦功率的增加，測量范圍擴大，靈敏度提高，當端面泵浦功率為7 . 24w （最大輸出功率為1 . 926w ）時，激光位移傳感器的測量范圍和靈敏度分別是13 . 045mm和0 . 148mw / pm 。The engineering work load detailed list reckoning method has the advantages of simple, clear, operation easily, remaining the account settlement rarely, etc compared with the present day running unit price budgeting method, which will be the direction of national engineering cost system reform, cost management first, this text states thoroughly the existing problem of the present day national engineering mode and price reckoning method, and the necessity of application right away and the existing problem, and then make a detailed discussion of the principle of quota reckoning and the engineering work load detailed list reckoning, so that we may be safe to draw such a conclusion that the new cost management system of the new price reckoning method is a necessary way to adapt to the international competition
工程量清單計價法與目前我國實行的預算單價法相比，有簡單、清晰、可操作性強、不易留結算尾巴等優點；是我國工程造價體制改革的方向。本文首先全面闡述了目前我國工程造價管理模式和計價方式存在的問題以及現在推行的必要性及存在的問題，進而對定額計價和工程量清單計價的原理進行了詳細的論述，從而得出實行新的計價方式的造價管理體制是適應國際化競爭的必走之路。然後，對即將實行的工程量清單計價模式各單位需要面對的風險，提出幾點抵禦風險措施。To the northwest and north of beijing, a huge, serrated wall zigzags it s way to the east and west along the undulating mountains
在北京西北和北面連綿的群山中，一道鋸齒形的高墻隨山勢起伏蜿蜒，向東西方向延伸，不見首尾。
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