【中国私企火箭发动机】
中国航天私企蓝箭航天公司的技术人员正在组装「天鹊A」液氧甲烷发动机，浙江湖州。「天鹊A」发动机是蓝箭航天公司自主研制的新一代液氧甲烷火箭发动机，分为12A、13A 和15A 三个型号，最大真空推力达85吨，主要用于朱雀二号商业运载火箭的动力系统，可实现燃烧无积碳和重复使用。这款火箭发动机已进入批量生产和交付阶段，预计2024年产量达到100台。 source
BY 每日环球视野
“To the extent it is used I fear it’s often for illicit finance. It’s an extremely inefficient way of conducting transactions, and the amount of energy that’s consumed in processing those transactions is staggering,” the former Fed chairwoman said. Yellen’s comments have been cited as a reason for bitcoin’s recent losses. However, Yellen’s assessment of bitcoin as a inefficient medium of exchange is an important point and one that has already been raised in the past by bitcoin bulls. Using a volatile asset in exchange for goods and services makes little sense if the asset can tumble 10% in a day, or surge 80% over the course of a two months as bitcoin has done in 2021, critics argue. To put a finer point on it, over the past 12 months bitcoin has registered 8 corrections, defined as a decline from a recent peak of at least 10% but not more than 20%, and two bear markets, which are defined as falls of 20% or more, according to Dow Jones Market Data.
In general, many financial experts support their clients’ desire to buy cryptocurrency, but they don’t recommend it unless clients express interest. “The biggest concern for us is if someone wants to invest in crypto and the investment they choose doesn’t do well, and then all of a sudden they can’t send their kids to college,” says Ian Harvey, a certified financial planner (CFP) in New York City. “Then it wasn’t worth the risk.” The speculative nature of cryptocurrency leads some planners to recommend it for clients’ “side” investments. “Some call it a Vegas account,” says Scott Hammel, a CFP in Dallas. “Let’s keep this away from our real long-term perspective, make sure it doesn’t become too large a portion of your portfolio.” In a very real sense, Bitcoin is like a single stock, and advisors wouldn’t recommend putting a sizable part of your portfolio into any one company. At most, planners suggest putting no more than 1% to 10% into Bitcoin if you’re passionate about it. “If it was one stock, you would never allocate any significant portion of your portfolio to it,” Hammel says.
每日环球视野 from sg