long-period variation 中文意思是什麼
long-period variation
解釋
長期變化-
The variation of wave - induced nearshore current fields and long period oscillation of water surface result in sediment transport, resonance of harbors, ship failures, diffusion of pollutants and difficult sea rescues, drawing scientific researchers " concern
由波浪產生的近岸流場的變化和水面的長周期振蕩，導致泥沙遷移，港口共振，船舶失事，污染擴散，海上救生困難，這些都已經引起了科研工作者的廣泛重視。 -
Abstract : the variation of residual energy of propellant in ammunition after long period storage is stud - ied
文摘:對彈藥在長期貯存過程中其發射藥剩餘能量的變化情況進行了研究。 -
As for frequency domain, tirls includes mainly 3 frequency bands : ( 1 ) high frequency band with period less than 1 year, which is relative to weather ; ( 2 ) mid frequency band with predominant period 1 year, relative to sun, plant and season ; ( 3 ) low frequency band with period more than 1 year, relative to the crustal activity and long period variation of atmosphere temperature
從頻率域看，地表熱紅外輻射主要存在3種頻段： （ l ）高頻，周期小於1年的天氣變化； （ 2 ）中頻，以1年周期為主的太陽、植被與季節變化； （ 3 ）低頻，大於1年周期的大氣變化的長周期成份，地殼緩慢的運動引起的熱輻射變化亦屬于長周期變化。 -
At present, many fields remain to further research, especially the profound combination of gis technique with ece ( estuarine and coastal engineering ), which should be developed for the purposes as follows : ( 1 ) to serve the huge comprehensive work in changeable natural conditions and difficult construction conditions which takes a long period and covers a large region, e. g. the regulation work of deepwater channel in the yre ( yangtze river estuary ) ( 2 ) to combine the gis with applied numerical model ( 3 ) to study the hydrodynamic processes and characteristics of waves, tidal currents and sediment transport, as well as the affection carried by the regulation work in an estuary ( 4 ) to monitor and to analyze ees ( evolution of erosion and sedimentation ) and the variation of riverbed ( 5 ) to play a role of dynamic supervising of a engineering project
目前尚有許多有待進一步研究的領域，尤其是以服務于長江口深水航道治理這樣規模大、周期長、影響區域廣、自然條件復雜、施工情況多變的國家重點工程為目的，將gis與專業應用數學模型結合，對河口海岸波浪、潮流、泥沙運動的動力機制，以及整治工程建築物對其影響的研究，對入海航道沖淤和河勢演變的監測分析，對施工進展和工程效果實現「動態」監控和管理，尚缺乏同gis技術的深入有效結合。
分享友人