natural experiment 中文意思是什麼

natural experiment 解釋
自然實驗
  • natural : adj 1 自然界的；關于自然界的。2 天然的；未開墾的；野生的。3 固有的 生來的 天賦的（opp acquired）...
  • experiment : n 實驗；試驗；嘗試 （of） a scientific experiment 科學試驗，科學儀器設備。 a new experiment in ed...
  1. They are jinfo mountain in nanchuan county ( natural protection section ), wuling mountain in qianjiang county ( national emphases forest demonstration county which forest cover rate is beyond 50 % ) and zhongliang mountain in beibei county ( artificial destruction is very grave ). some main land use patterns i. e. woodland, garden, infield, abandon infield, shrub and grassplot are selected in those three sample sites. four aspects on soil fertility index of karst environment under different land use patterns in these three sample sites, are revealed in this paper, by using the field test, indoor measure and analysis, outdoor experiment and field investigation, and the knowledge and technique of soil, ecology, physics and chemistry etc. they are physical characteristic ( effective soil thickness, organic layer thickness, soil texture, water - stable aggregate and soil water etc. ), chemical fertility ( organism, omni - n, omni - p, omni - k, alkali - nitrogen, available p, available k and rapid available k etc. ), soil animalcule ( bacteria, fungi, actinomyces and their grosses ) and soil - seed - pool ( plant community diversity index ) in karst ecosystem

    本研究以重慶市的南川金佛山（自然保護區） 、黔江武陵山（國家重點退耕還林示範縣，森林覆蓋率50以上）和北碚中梁山（遭人為破壞嚴重）典型巖溶區為對象，選擇了幾種重要的利用方式，包括林地、果園、耕地、棄耕地和灌草坡，採用野外巖溶生態調查和室內試驗測量分析相結合的方法，以不同土地利用方式巖溶土壤肥力為重點，對不同土地利用方式土壤肥力特徵進行量化分析，找出巖溶土壤肥力差異的主要方面及其根本原因，論文主要從土壤剖面物理退化指標（有效土層厚度、有機質層厚度、質地、團聚體、水分含量等） ，化學肥力退化指標（有機質、全n 、全p 、全k 、堿解n 、速效p和速效k等） ，樣地土壤微生物指標（細菌、真菌、放線菌數量及總量）以及樣地土壤種子庫植物群落多樣性等4個方面對重慶典型巖溶區的土壤肥力特徵進行了較為詳細的分析研究，為巖溶地區士壤資源的合理利用及結構的調控管理提供依據。
  2. Subjects of two groups executed an same incremental ergometer exercise up to exhaustion. after exercise, compared with the natural recovery in the control group, somin hyperoxia ( 70 % oxygen ) was given to the experiment group

    20名體育學院健康男生隨機分為兩組（吸氧組和對照組） ，實驗要求全體受試者完成一次性遞增負荷運動，運動至力竭，觀察運動即刻和恢復期各指標的變化情況。
  3. Different algorithms were compared in the numerical simulation and model experiment of concrete velocity inversion the results showed that, compared with the least - square solutions and the damped least - square solutions, the damped and natural weighted least - square solutions reflected the inner defections of the tested object more reliably and exactly due to the usage of correct priori information, which benefited the suppression of noises and made the iterations of inverse stable and convergent

    結果表明，相對于最小二乘法和阻尼最小二乘法，基於自然權的加權阻尼最小二乘演算法，由於利用了正確的先驗信息，不但使反演過程收斂，而且具有數值穩定、抗噪能力強的優點，其成像結果能真實有效地反映對象內部缺陷，因此更適用於混凝土的超聲波速度反演。
  4. 3. a number of test parameters of insulation, position of reflux pipe inlet arrangemts, injection etc. are explored in the experiment. the experimental results demonstrate that the natural circulation is an efficient way to precool the pump system and maintain it at cryogenic temperatures

    進行了多組對比實驗，著重對兩種不同迴流方式對于自然循環和預冷的影響進行了比較，並研究了系統增壓、引射、迴流管絕熱效果以及泵體絕熱效果對于自然循環的建立和維持以及對循環預冷效果的影響。
  5. Directional silviculture experiment and benefits of natural secondary broad - leaf forest

    次生闊葉林定向培育試驗及效益研究
  6. ? as same as most other schizothoracinae fishes, qinghai - lake nakked car ps may be tetraploid that already were diploidization ; ? qinghai - lake nakked carps arose from some primitive barbinae fishes, which gradually became special population adapting to high altitude environment by involvement and natural selection, on protein electrophoresis, out of 20 protein loci among 132 individuals in the present experiment, only t mdh > amy est and pod showed polymorphism

    在蛋白水平上，共檢測了132尾裸鯉的20個遺傳座位，僅發現tf ， mdh 、 amy 、 est和pod五個座位表現出多態性，其中， tf 、 mdh 、 amy和est四個座位均有一對等位基因；而pod座位表現出復雜的電泳圖譜，未進行深入分析。
  7. In the extended experiment we modulate the sand grain diameter and air humidity to contrast with the natural result, discuss the effect of diameter and humidity on sand incipience, propose some ideas and methods to control sand transportation and formulation of wind - blow - sand flow

    本文還拓展了實驗條件，通過調整沙粒粒徑配比和空氣濕度，完成了對比性實驗，並進一步探討了粒徑和濕度對沙粒起動的影響，提出了在沙漠工程中控制風沙流形成和沙粒輸運的思路和方法。
  8. The paper is based on the project of national natural science foundation " the intelligent control system of ship on bumping and avoiding bumping " and " the study based on the impulsion response of light duty configuration, control and experiment method of high speed ship ". the fuzzy adaptive control is applied to ship steering. it is significant to improve automation technology of ship in china

    本論文以國家自然科學基金項目「船舶碰撞與避碰的運動機理及計算機智能模擬系統研究」和「基於高速船輕型結構流體沖擊響應、控制與實驗方法研究」為依託，將模糊自適應控制應用於船舶的航向控制，這些研究將對我國船舶自動化水平的提高具有較大現實意義。
  9. The bleaching experiment of loess by iodine tungsten lamp and the equivalent dose ( de ) of loess estimated by sar from the earth ' s surface indicate that loess can be easily bleached by sunlight, and osl is suitable for the dating of loess. 2. equivalent dose estimated by sar, when each natural or regenerated dose osl measurement is corrected for changes in sensitivity using the osl response to a subsequent test dose and the recycling ratio is around 1, implies that sensitivity changes have been properly corrected

    用單片再生劑量法（ sar ）測定黃土樣品的d _ e值時，用固定的實驗劑量釋光信號校正後，再循環比（ recyclingratio ）都在1左右，說明對釋光靈敏度的變化起到了很好地校正作用；校正後， ogy再生劑量釋光信號與自然信號的比率都在5以下，信號的回復可以忽略不計。
  10. How to develop pupils ' cooperation awareness amp; amp; abilities in experiment of natural science class

    自然課實驗教學應如何培養學生合作意識和能力
  11. The dynamic response of the experiment model is studied by transfer function response, and the natural frequency and vibration mode of the vibration system are measured, the dynamic characteristic is mastered, which provides the experiment test method of dynamic data for the structure design of reinforced concrete and the shock absorber design of the system, especially provides the design rules to vibration control of the machine equipment which are built in the building structure

    用傳遞函數響應方法對實驗模型進行動態響應實驗研究，測得振動系統的固有頻率和振型，掌握振動系統的動態特性，為鋼筋混凝土建築的結構設計和系統減振設計提供動力學的實驗測試方法，尤其給安裝在建築物內機械設備的振動控制提供了設計依據。
  12. Then, we establish the finite element analysis models of the antenna in different structure layout, and obtain the corresponding frequencies and model shapes. finally, according to the importance of each object, we set up the model of multiple objects that aims to maximize the first natural frequency and minimize the mass. combining orthogonal experiment and variant weighting coefficient method, we formed an effective multiple objects optimized algorithm basing on the neural network and genetic algorithm

    本文首先詳細的敘述了天線結構的各組成單元，闡明了天線反射拋物面的形成原理；然後在ansys軟體環境中建立了不同結構布局下天線的有限元分析模型，分析計算了各種情況下天線的的固有頻率與振型；最後依據天線各指標的重要性，建立了以一階固有頻率最大、質量最小為目標的天線結構多目標優化設計模型，並基於神經網路和遺傳演算法，結合正交實驗和變加權系數技術，形成了一種有效的多目標優化演算法，在matlab平臺下實現了天線的結構多目標優化設計計算程序，求得了天線的最佳結構參數。
  13. Abstract : by using the self - regulating electrostatic drying equipment, theelectrostatic drying for plant leaves is studied. the equipment is a surface silent discharge ozone generator. the electrostatic drying and natural drying are compared experimentally. the result shows that the electrostatic field is more effective for plant drying. the polarity characteristics of the electrostatic drying is discovered during the experiment and discussed. for accelerating drying, the polarity characteristics should be considered in the drying equipment design

    文摘:在自製的沿面式無聲放電臭氧發生裝置上，對植物葉片進行了乾燥實驗.通過對植物靜電乾燥和自然乾燥的比較，證實靜電場對植物有明顯的乾燥效果.發現了靜電乾燥中的極性效應，即當管狀電極的極性為負時，乾燥速度較快.對極性效應進行了探討和分析.實驗結果表明:沿面式無聲放電臭氧發生裝置可以有效地對植物進行靜電乾燥.研究結果對有效地利用靜電乾燥和極性效應來合理設計靜電乾燥裝置的結構具有重要意義
  14. The self - poisoning effects of chinese fir plantation are studied through the seed germination experiment with the extracts of organs, bulk soils and rhizosphere soil of different rotation plantations. the results are as follows : there are some poisonous substances inhibiting germination of chinese fir seeds in soils of chinese fir plantations. the inhibiting effect becomes stronger and stronger with increase of planting generations. extracts from the organs of chinese fir trees also have some inhibiting effects on seed ' s germination, but the effect of leaf is the strongest. lower concentration extracts of underground vegetation may be favorable to the seed ' s germination whereas the higher concentration will reverse the results. it indicates that the “ self - poisoning ” effects of chinese fir plantations might be one of the reasons for poor natural regeneration and soil degradation of chinese fir plantation

    利用不同栽植代數杉木人工林根際土、非根際土及杉木各器官浸提液進行杉木種子發芽試驗，研究杉木人工林自毒作用，研究結果表明：杉木林根際土及非根際土中均存在抑制杉木種子萌發的物質，隨栽植代數增加抑制作用更趨明顯；杉木各器官浸提液對杉木種子萌發也有抑制作用，其中以杉木葉的抑制作用最為明顯，杉木林下常見植物對杉木種子發芽則表現為低促高抑效應，說明杉木人工林存在自毒作用，這可能是杉木連栽障礙的原因之一。
  15. Besides, the natural core in - house long - term washing out experiment has proved that waterflood efficiency of pressure coring can reach as high as 80 % ~ 90 %

    天然巖心室內長期水沖刷實驗證實了密閉取心的水驅油效率可達80 % ~ 90 % 。
  16. The research result of insect community development indicate : the differences to quantity and richness of pest, natural enemy and whole insect community among experiment sections are distinct. the dynamic uptrend of diversity and evenness indexes between harmless section and general section are analogical, but that of blank section and two manage sections is different

    昆蟲群落動態研究結果表明：各試驗區間害蟲、天敵及整個昆蟲群落的數量與豐富度差異明顯，無公害區與常規區各群落多樣性指數、均勻性指數動態變化趨勢一致，空白區與兩處理區多樣性指數、均勻性指數動態變化趨勢差異較大。
  17. It can be concluded from the experiment results that hatchery seed has lower genetic variation and large - scale hatchery seed releasing affects the genetic diversity of the natural population. the shrimp distributed along china coast in bohai sea and yellow sea may consist of more than one populations. the viral disease resistant ability of f. chinensis is proved to be genetically inherited and can be improved by genetic selection

    一通過對實驗結果的進一步分析認為：中國對蝦人工育苗的過程使後代群體的遺傳多樣性下降，人工培育苗種的大規模放流影響了自然群體的遺傳多樣性； ，分佈於我國沿海的中國對蝦可能由多個自然群體構成，還存在未被發現的種質資源：中國對蝦抗wssv病毒感染是由遺傳決定的，選育可提高中國對蝦對wssv的抗性。
  18. Connecting with country ' s natural scientific fund item and water resources and environmental important experiment item of shann ' xi province, on the basis of large sum of reading about domestic and overseas relative literatures, according to the rainfall data, including per day and per hour rainfall data of 21 years ( from 1980 to 2000 ), the paper analyzed the rainfall characters

    本文結合國家自然科學基金項目和陜西省水資源與環境重點實驗室建設項目，在閱讀並綜述了大量國內外相關文獻基礎上，根據西安市馬渡王水文站的21年（ 1980年- 2000年）降雨時、日資料，分析了西安市降雨特性。
  19. There is high rate of problem behaviors among junior high school students because of the particularity in the development of their body and mind this paper studies the types and characteristics of problem behaviors among junior high school students by questionaire method. interview method and literature analysis. based on that, the paper also works out a new problem behavior scale for junior high school students as the measuring tool. then the research has the natural experiment for educational intervention collectively and individually

    初中生因其身心發展的特殊性，成為問題行為的高發人群。本研究通過問卷和訪談調查以及文獻分析，探析初中生常見問題行為的類型和特點，並在此基礎上自編初中生問題行為量表。然後運用集體干預和個別干預相結合的自然實驗對初中生進行教育干預，並以自編量表為測量工具考察實驗效果。
  20. The study investigates how the communicative attribution of 4 - graders is when they communicate with different individuals in different situations. on the basis of the investigation, the study conducts natural experiment on different types of children by collective and individual intervention, we attempt to advance the communicative attribution of low - social statues children, and to improve the environment of their of their social communications

    本研究擬就同伴交往機制的重要環節? ?交往歸因進行研究。本研究採用問卷調查法，系統考察了小學4年級兒童的同伴交往歸因情況，並在調查的基礎上，針對不同類型兒童實施了集體干預與個別干預相結合的自然實驗。
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