最令航天业担忧的是钇供应紧张。钇是高温防护涂层中的关键成分，可防止发动机和涡轮在高温下“熔化”，一旦无法定期施涂相关涂层，发动机便无法正常服役。
10. 联合国报告：全球经济展现韧性但增长乏力贸易紧张与债务压力拖累前景 - the United Nations, www.un.org/ru/node/238…
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It is not for lack of trying. In some cases, microbiologists have ditched the Petri dish altogether, using microfluidics for manipulating and growing cells. However, these approaches aren’t likely to be adopted at scale as they require less common, less practical, and more expensive devices. So, what about other growth media?
从“大而全”转向“特色化”。邮轮需要找到自己的核心定位和目的地标签。是主打亲子、主打银发，还是主打文化主题？总要有一个突出的特色标签，才能支撑起高票价和用户忠诚度。
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