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1 Primary & Middle School Mathematics1–9 年级在线 2 High School Mathematics10–12 年级在线 3 University Mathematics — Year 1本科一年级在线 4 University Mathematics — Year 2本科二年级在线 5 University Mathematics — Year 3本科三年级在线

1 Primary & Middle School Physics1–9 年级在线 2 High School Physics10–12 年级在线 3 University Physics — Year 1本科一年级在线 4 University Physics — Year 2本科二年级在线 5 University Physics — Year 3本科三年级在线

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1 Markets I: The Ecosystem and Exchange-Traded Markets市场在线 2 Markets II: Rates, FX and Credit市场在线 3 Markets III: Commodities, Energy and Crypto市场在线 4 Quantitative Methods方法在线 5 Derivatives and Volatility衍生品在线 6 Rates, Credit, XVA and Risk利率、信用与风险在线 7 Research Craft: Predictors, Backtests, Measurement, Portfolios研究在线 8 Strategies I: Equities and Futures策略在线 9 Strategies II: Volatility, Relative Value, Macro and the Bank Desks策略在线 10 Microstructure and Execution交易执行在线 11 Market Making and High-Frequency Trading做市在线 12 Machine Learning for Markets机器学习在线 13 Low-Latency Software技术在线 14 Networks, Hardware and Trading Infrastructure技术在线 15 Research, Data and Risk Platforms技术在线 16 The Desk and the Firm公司运营在线 17 The Industry: Firms, Roles and Careers职业发展在线 18 Interviews I: Maths, Probability and Speed职业发展在线 19 Interviews II: Markets, Trading Games and the Final Round职业发展在线 20 Interviews III: Code职业发展在线

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Earth and Space Sciences · 术语表

什么是 Dune？

又称： slip face

Definition 31.2 Primary & Middle School Earth and Space Sciences · 第 31 章 — Landforms

A dune is a mound or ridge of loose sand heaped up by the wind. Its slope facing the wind is long and gentle; its far side, the slip face, is short and steep.

A crescent dune, or barchan (a sketch). Seen from above, its horns point downwind. Seen from the side, the grains climb the gentle windward slope and slide down the steep slip face: the dune moves downwind (dashed outline: the dune a little later).

Crescent-shaped dunes on the Atlantic coast of southern Brazil, photographed by an astronaut from the International Space Station in 2017. The dark lake, Lagoa dos Barros, is about 4.5\, km long. The sand comes from the beach, at the bottom of the photograph. NASA (public domain, via Wikimedia Commons). — Crescent-shaped dunes on the Atlantic coast of southern Brazil, photographed by an astronaut from the International Space Station in 2017. The dark lake, Lagoa dos Barros, is about $4.5\,\mathrm{km}$ long. The sand comes from the beach, at the bottom of the photograph. NASA (public domain, via Wikimedia Commons).

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