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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

1 School Chemistry — Grades 1 to 121–12 年级在线 2 University Chemistry — Year 1本科一年级在线 3 University Chemistry — Year 2本科二年级在线 4 University Chemistry — Year 3本科三年级在线

1 Primary & Middle School Biology1–9 年级在线 2 High School Biology10–12 年级在线 3 University Biology — Year 1本科一年级在线 4 University Biology — Year 2本科二年级在线 5 University Biology — Year 3本科三年级在线

1 Primary & Middle School Earth and Space Sciences1–9 年级在线 2 High School Earth and Space Sciences10–12 年级在线 3 University Earth and Space Sciences — Year 1本科一年级在线 4 University Earth and Space Sciences — Year 2本科二年级在线 5 University Earth and Space Sciences — Year 3本科三年级在线

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 Spring and well？

又称： spring · well

Definition 17.8 Primary & Middle School Earth and Space Sciences · 第 17 章 — Water Underground

A spring is a place where groundwater comes out of the ground by itself, where the water table meets the surface. A well is a hole dug or drilled down below the water table, so that groundwater fills its bottom and can be lifted out.

A north–south section through the Varden Hills, from the river up the northern hillside (heights exaggerated about 2 times). The water held in the chalk stops on the shale and comes out as a spring where the base of the chalk meets the slope. Well A always reaches the water; well B reaches it only after the rainy season.

Children fill a bucket at the hand pump of a village well. (AI illustration.)

示例

Example 17.12 (A new fuel tank for the farm)

A farmer on a chalk hillside drinks the water of her own well, halfway up the slope, and wants to put a new fuel tank in one of two fields: one uphill of the well, one downhill of it, near the stream. The groundwater flows downhill. A leak from the field uphill would drift down towards the well; a leak from the field downhill would drift away from it, towards the stream. The field downhill of the well is the better choice for the well — and a tank on a tray that holds any leak is better still, since the stream matters too.

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