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Upending an evolutionary theory proposed in the 1950s, scientists have found that the groups of animals most resistant to extinction also contain the greatest ecological diversity –- their members per...
Researchers find new reason why Arctic is warming so fast（图）
new reason Arctic warming so fast
2020/2/28
The Arctic has experienced the warming effects of global climate change faster than any other region on the planet. Scientists at the Scripps Institution of Oceanography have developed a new theory ai...
So Many Microbes, So Little Time, and So Little Money: Needs and Challenges in Developing a Global Network of Biological Resource Centers
Time Money Microbes
2015/7/29
When microbiologists first applied the tools of their trade to the oceans of the world, they quickly learned that water samples contained variable numbers of bacteria, depending on sample location and...
Why is the Northern End of the California Current System So Productive?
Northern End California Current System
2015/7/22
Although scientists have long believed that, in an eastern boundary current system, alongcoast wind stress is responsible for the upwelling of deep nutrients that initiates phytoplankton blooms, the C...
Valuable mineral resources are widely distributed throughout the seabed. autonomous underwater vehicles (AUVs) are preferable to remotely-operated vehicles (ROVs) when probing for such mineral resources as the extensive exploration area makes it difficult to maintain contact with operators. AUVs depend on batteries, so their power consumption should be reduced to extend exploration time. Power for conventional marine instrument systems is incorporated in their waterproof sealing. External intermittent control of this power source until termination of exploration is challenging due to limitations imposed by the underwater environment. Thus, the AUV must have a power control system that can improve performance and maximize use of battery capacity. The authors developed such a power control system with a three-step algorithm. It automatically detects underwater operational states and can limit power, effectively decreasing power consumption by about 15%.
surface piercing propeller boundary element method hydrodynamic characteristics
2011/9/13
Demand for high-speed marine vehicles (HSMVs) is high among both commercial and naval users. It is the duty of the marine vessel’s designer to provide a hull and propulsion system that diminishes drag...