等年變率線 的英文怎麼說
中文拼音 [děngniánbiànlǜxiàn]
等年變率線
英文
isopors-
Disigning coolant channel on the firebox of liquid rocket engine to loxodrome ( equal - angle helix ) groove can improve firebox coolant capability greatly. because the width dimension of loxodrome groove is narrow and the depth is deep, some machining methods are incapable, such as end - milling or electrochemistry. according to the peculiarities, a cnc disk - cutter - milling method which is composed of five motion axes with four simultaneously interpolated ones is researched. because most firebox generatrix is composed of complex curves, it is very difficult to get cnc cutting program with manual means. in order to deal with the problem, the loxodrome mathematics model is studied, and an auto - programming software system is developed. the software system can generate cnc cutting program of loxodrome on many kinds of turned surface. the constriction - distension segment of firebox is the most representative workpiece. the sharp changing of its generatrix slope makes loxodrome milling difficult. with the theory analyzing and practice cutting experiment, some applied techniques, which include milling mode and direction, choosing cutter diameter and cutting start point setting, are developed. adopting the technology above, tens regular workpiece have been manufacturing. the two - year manufacture practice has confirmed the validity and feasibility of developed loxodrome coolant channel milling method. the developed technology is also worth to be referenced to other similar workpiece
將液體火箭發動機燃燒室的冷卻通道設計為斜航線（等傾角螺旋線）槽形，可以大幅度改善燃燒室的冷卻性能.斜航線冷卻槽的槽寬尺寸較小而槽深尺寸較大，所以無法使用棒銑刀銑削、電化學等加工方式.針對這些特點，提出了五軸控制、四軸聯動的數控片銑刀銑削加工方法.由於燃燒室外表面的母線輪廓復雜，手工編制數控加工程序難度大.為了解決數控加工程序的編制問題，研究了斜航線的數學模型，開發了自動編程軟體系統.使用該系統，可以生成多種母線輪廓回轉體外表面上的斜航線數控加工程序.燃燒室收斂-擴張段的母線斜率變化大，加工難度大，是斜航線冷卻通道加工的最典型工件.經過理論分析和實際切削實驗，研究了針對該類型工件的片銑刀直徑選擇、銑削方式和方向、刀具調整和起刀點的設置等多項實際的加工方案.採用上述的一系列技術，已經成功地加工了數十個合格工件.經過兩年多的實際生產過程應用，驗證了所開發的斜航線冷卻通道加工方法的正確性和可行性.這些加工技術的研製成功，對其他相似類型零件的加工亦具有參考意義Abstract : biological invasions are a continuous feature of a non - equilibrium world, ever more so as a result of accidental and deliberate introductions by mankind. while many of these introductions are apparently harmless, others have significant consequences for organisms native to the invaded range, and entire communities may be affected. here we provide a survey of common models of range expansion, and outline the consequences these models have for patterns in genetic diversity and population structure. we describe how patterns of genetic diversity at a range of markers can be used to infer invasion routes, and to reveal the roles of selection and drift in shaping population genetic patterns that accompany range expansion. we summarise a growing range of population genetic techniques that allow large changes in population size ( bottlenecks and population expansions ) to be inferred over a range of timescales. finally, we illustrate some of the approaches described using data for a suite of invasions by oak gallwasps ( hymenoptera, cynipidae, cynipini ) in europe. we show that over timescales ranging from 500 10000 years, allele frequency data for polymorphic allozymes reveal ( a ) a consistent loss of genetic diversity along invasion routes, confirming the role of glacial refugia as centres of genetic diversity over these timescales, and ( b ) that populations in the invaded range are more subdivided genetically than those in the native range of each species. this spatial variation in population structure may be the result of variation in the patchiness of resources exploited by gallwasps, particularly host oak plants
文摘:生物入侵是不均衡世界的一個永恆話題，尤其是當人類有意或無意地引入物種后.很多引入顯然是無害的，但另外一些則有著嚴重的後果，會給入侵地的生物以至於整個生物群落造成影響.本文總結了分佈區擴張的常見模式，概述了它們對遺傳多樣性和種群結構式樣所造成的影響.描述了如何根據以一批遺傳標記所得到的遺傳多樣性式樣來推斷入侵途徑，來揭示伴隨擴張選擇和漂變在形成種群遺傳樣式中的作用.本文對日益增多的群體遺傳學方法進行了總結，這些技術可以用來在不同的時間尺度上推斷種群規模所發生的巨大變化（瓶頸效應及種群擴張） .最後，我們以歐洲櫟癭蜂（膜翅目，癭蜂科，癭蜂族）一系列入侵的數據為例對一些方法進行了說明.從500 10000年的時間尺度上，多態的等位酶位點上等位基因頻率的數據表明: 1 ）遺傳多樣性沿入侵路線呈不斷下降的趨勢，支持了冰河期避難所作為遺傳多樣性中心的作用; 2 ）入侵地區的種群與該物種原產地的種群相比，遺傳上的分化更為強烈.這種種群結構在空間上的變異可能是被櫟癭蜂開發的資源尤其是櫟樹寄主在斑塊上出現變異的反映This increase was primarily due to strong sales growth in all lines of business driven by ready market acceptance of new products, particularly in variable annuities ; strong recurring premiums in the 401 pension business ; excellent retention in the insurance business ; and an improved economic environment
是項增長主要是由於新產品，尤其是變額年金產品深受市場歡迎401 k退休金業務錄得可觀的經常性保費保險業務的續保率高企，以及經濟環境改善等因素影響，令全線業務銷售大幅上升。
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