首次定位時間 的英文怎麼說

中文拼音 [shǒucìdìngwèishíjiān]
首次定位時間 英文
ttff time to first fix
  • 首 : Ⅰ名詞1 （頭） head 2 （首領） leader; head; chief 3 （表示方位） aspect 4 （姓氏） a surname Ⅱ動...
  • 次 : Ⅰ名詞1 （次序; 等第） order; sequence 2 [書面語] （出外遠行時停留的處所） stopping place on a jou...
  • 定 : Ⅰ形容詞1 （平靜; 穩定） calm; stable 2 （已經確定的; 不改變的） fixed; settled; established Ⅱ動詞...
  • 位 : Ⅰ名詞1 （所在或所佔的地方） place; location 2 （職位; 地位） position; post; status 3 （特指皇帝...
  • 時 : shí］Ⅰ名1 （比較長的一段時間）time; times; days:當時at that time; in those days; 古時 ancient tim...
  • 間 : 間Ⅰ名詞1 （中間） between; among 2 （一定的空間或時間里） with a definite time or space 3 （一間...
  • 首次 : for the first time; first
  • 時間 : time; hour; 北京時間十九點整19 hours beijing time; 上課時間school hours; 時間與空間 time and spac...
  1. Firstly, in spherical coordinate system, the sovp formulation for the time - harmonic electromagnetic fields of the current dipole in conductive infinite - space is derived, using reciprocity theorem and transforming relations between special functions. then, selecting appropriate coordinate system, using superposition principle, the boundary - value problem of modified magnetic vector potential on the problem of a time - harmonic current dipole in spherical conductor is solved and analytical solution is obtained. finally, by means of the addition formulas of legendre polynomial and spherical harmonics function of degree n and order 1, the analytical solution in spherical coordinate system specially located is transformed into that in spherical coordinate system arbitrarily located

    首先利用特殊函數間的轉化關系和互易定理推導得到了無限大導體空間中球坐標下時諧電流元電磁場的二階矢量位形式：然後利用疊加原理，選擇合適坐標系，求解了導體球中時諧電流元的修正磁矢量位邊值問題，得到了問題的解析解；最後依據不同坐標系下電磁場解的轉化原理，藉助勒讓德多項式和n次1階球諧函數的加法公式，將坐標系特殊安放時的電磁場解析解變換到坐標系一般安放時的解析解，給出了球內電場和球外磁場的並矢格林函數。
  2. First, the nonlinear ls problem without constraint is converted to that subjected to inequality constraints by putting constraints on the do as of the received signals and toas of the first arrived signal with geometrically based single - bounce ( gbsb ) statistical channel model and cost - 207 model. then, a penalty function is used in the estimation of ms position

    首先，用基於幾何結構的單次反射圓模型和cost - 207模型，對期望定位用戶的各條多徑信號的波達方向和最先到達多徑信號的時間進行約束，將傳統的解無約束的非線性最小二乘定位問題或近似線性最小二乘定位問題轉化為解不等式約束的非線性最小二乘定位問題；然後，用內點罰函數法估計移動臺的位置。
  3. If you a have a column that has a skewed data distribution, a histogram on it and if you are using bind variables against that column you may suffer from the same problem

    大致意思是，綁定變量的窺視，在你的某欄位有不均衡的數據分佈，又有柱狀圖的情況下，首次執行的語句生成了對其有利的執行計劃，它會將計劃帶個所有後面的語句，不管後面語句的執行時間會花費多久
  4. In order to grasp the urban system processes and evolution pattern of hunan province comprehensively, this article has made further discussion on its structure characteristic : through regression analysis, graph analysis and statistics analysis of the time series data and cross sections data, by combining with the fractal theory, we induce the following conclusion : the hierarchical size structure presents the law of the primate city, the rank - size rule and pyramid structure characteristic, but it also has the insufficient development problem of the high hierarchical size city. by using the gravitation model, we found out that the economy relation intensity among those main cities is weak while the structure is loose. based on the urban layer system of economic development level and industrial structure evolution of the cities in hunan province, this article then induces the function combination among the five urban agglomerations in hunan province

    為全面把握湖南城市體系的運演規律，本文對其結構特徵作了進一步的探討:通過時序數據和截面數據的回歸分析、圖表分析和統計分析，結合分形理論，得出了其等級規模結構分佈呈現出首位分佈、位序?規模分佈和金字塔結構特徵，以及存在著高層次城市發展不足的問題;運用場引力模型發現該省主要城市間的經濟聯系強度較弱、結構鬆散，在歸納出該省城市經濟發展水平的層次體系、產業結構演變的基礎上，導出了該省城市體系的五大城市群職能組合;結合空間結構體系、路網交通條件和經濟發展狀況，對該省城市空間分佈狀態進行了定性分析，研究表明該省總體上處于極化階段，各個具體區域，分佈階段不一，差異較大。
  5. 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 。
  6. The main features in the study of flood forecasting and control system are as follows : ( 1 ) runoff generating and confluence theory and hydro - dynamic method are adopted to predict the water level of taihu lake and key nodes, the basin wide forecasting and control system with the function of real time correction has been first established in plain river network to meet the complicated flow conditions of taihu lake basin and to enhance the reliability of forecasting results ; ( 2 ) according to the rainfall in foreseen period multiple schemes can be made in the forecasting model and adjusted with time, which overcomes the errors caused by the uncertain rainfall in the foreseen period so as to make the forecasting results approach reality

    本文所研究的預報調度系統有如下特點： （ 1 ）本系統採用產匯流理論和水動力學方法預報太湖及重要節點水位，首次在平原河網地區建立了具有實時校正功能的全流域預報調度系統。以適合太湖流域復雜的水力條件，增強預報的可靠性; （ 2 ）預報模型可以根據預見期降雨量進行多方案預報，並隨時間推移，可以實時進行調整，克服由於預見期降雨不確定引起的誤差，使預報結果更接近實際。
  7. 2. co ( salen ) / nafion modified platinum electrode ( 1 ) the nitric oxide in the medium of natural seawater was determined using co ( salen ) / nafion modified platinum electrode for the first time, the best conditions are found as follows : the time of exclusion of oxygen bubbled with nitrogen for the electrochemical cell is 30min, the preparation time of saturated solution is 30min, the enrichment time is 3min when the concentration of nitric oxide is 10 - 6 mol / l and 7min when 10 - 7 mol / l and the electrochemical responses of the modified platinum microelectrode to no were evaluated by scanning from 0. 2v to iv

    天然海水介質中~氧化氮的電化學鋇定二、 eo （ sa一en ） znanon修飾電極1 .首次用co （ salen ）閃afion修飾鉑電極對天然海水介質中的一氧化氮進行了測定，確定了最佳實驗條件，即反應池通氮除氧30min ， no飽和溶液的制備時間為3omin ， no溶液濃度在10一6mol / l時?富集時間是3min ，濃度在10一7mol / l時富集時間是7min ，電位掃描范圍0 . 2一1
  8. Ttff - time to first fix

    首次定位時間
  9. Nation modified platinum electrode ( 1 ) the nitric oxide in the medium of natural seawater was determined using nafion modified platinum electrode for the first time, the best conditions are found as follows : the time of exclusion of oxygen bubbled with nitrogen for the electrochemical cell is 30min, the preparation time of saturated solution is 30min, the enrichment time is 5min and the electrochemical responses of the modified platinum microelectrode to no were evaluated by scanning from 0. 2v to iv

    主要研究結果如下：一、 nafion修飾鉑電極1首次用nafion修飾鉑電極對天然海水介質中的一氧化氮進行了測定，確定了最佳實驗條件，即反應池通氮除氧30min ， no飽和溶液的制備時間為30min ，富集時間是5min ，電位掃描范圍0 . 2 1 . 0v ，並且確定了nafion修飾電極的檢出限是1 mol l ，線性范圍1 76 . 9 mol l ，相關性良好。
  10. Firstly, in wireless environment, receiver has no know the time delay between transmitter and itself. in ofdm system, ofdm data is transmitted as one symbol, so in order for correct demodulation, the correct start of symbol should be got from ofdm system to reduce the effect of isi. secondly, the high frequency utilization in ofdm is based on the orthogonal properties of sub carriers. if frequency offset is generated, the orthogonal properties among sub carriers will lost, that will cause inter carrier interference ( ici ) and high ber of system

    Ofdm技術也存在著一些缺陷，首先，在無線環境中傳輸的ofdm信號對定時要求高，為了減少碼間串擾（ isi ）影響，必須從接收信號中提取出正確的符號起始位;其次， ofdm系統對頻率偏移敏感， ofdm技術的高頻譜利用率和傳輸可靠性均以子載波的正交性為基礎，如果接收機和發射機之間發生頻率偏移，子載波之間就會失去正交性，導致嚴重的子載波間干擾（ ici ） ，降低系統性能。
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