employor
发表于 2025-3-26 21:20:43
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禁止
发表于 2025-3-27 05:10:59
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不来
发表于 2025-3-27 08:53:20
i der Behandlung der ambipolaren Diffusion hatten wir für die Formulierung der Randbedingungen von der Tatsache Gebrauch gemacht, daß Ladungsträger, die auf eine Wand treffen, dort entladen oder absorbiert werden. Die Ladungen verschwinden aus dem Gasraum. Dieser Prozeß wird als . bezeichnet. Man sp
Ligneous
发表于 2025-3-27 12:42:31
ly, industrially and particularly with the depletion of high-grade deep-mined mineral reserves. Low-grade minerals require low cost extraction and this in many cases necessitates very expensive mechanized equipment with the cost of individual units running into millions of pounds in the case of larg
Oversee
发表于 2025-3-27 16:06:34
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infinite
发表于 2025-3-27 19:25:33
Quarrying Hard Rocks,rtain properties render some varieties particularly suitable for the purpose. Essential properties, apart from considerations of divisional planes, jointing, bedding or cleavage, are those associated with strength and durability. The material must not only bear the stresses the engineer or architect
大雨
发表于 2025-3-28 00:05:49
Working Iron and Copper Deposits by Open Pits,lack’ or ‘magnetic ore’; haematite, Fe.O., is a red ore with 70% iron; limonite, 2Fe.O.3H.O, is a yellowish-brown ore with varying amounts of water in its composition and contains 60% iron; siderite, FeCO., known also as chalybite or spathic iron ore has a theoretical iron content of 48%. In additio
chlorosis
发表于 2025-3-28 03:52:57
Opencast Coal, and the necessity for maintaining as far as possible the supply for domestic purposes during World War II led to the exploitation by opencast methods of those deposits of coal which occur at, or relatively near to, the surface.
空气传播
发表于 2025-3-28 09:31:59
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Fibrinogen
发表于 2025-3-28 13:01:51
Alluvial Mining,as also been advanced that the discovery of new mineral reserves is not keeping pace with the increased demand for minerals necessitated by an increasing world population with a rising standard of living. It should be borne in mind, however, that four-fifths of the earth’s surface is under water and