题干

已知:|a﹣2|+(b+1)2=0,求a+b2015的值.

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答案(点此获取答案解析)

解:由题意得,a﹣2=0,b+1=0,

解得a=2,b=﹣1,

则a+b2015=1.

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阅读理解

    A drug that is used to treat serious bleeding could save thousands of lives of mothers giving birth. A world test of the drug found it reduced (降低) the risk of bleeding deaths during childbirth by nearly one third. The study included 20,000 women in 21 countries, mainly in Africa and Asia. The test was carried out by London School of Hygiene and Tropical Medicine. The drug is called tranexamic acid (凝血酸). It is low-cost and researchers said it does not cause serious side effects (副作用) for mothers or babies.

    The drug is used to treat mothers for serious bleeding during childbirth. Postpartum hemorrhage (产后出血) is the main cause of mothers' death around the world, according to the World Health Organization.

    Haleema Shakur is the project director for the test. She said though medical condition is improved in many countries, serious bleeding after childbirth remains a big problem in some parts of the world. “It's one of the biggest killers of mothers. In Africa and Asia, about 10% of women will end up with serious bleeding.” The drug works after a mother gives birth.

    Shakur said the best results were reported when the drug was given to women as soon as possible after childbirth. “The earlier you give it — within the first three hours after giving birth — the better the result is.”

    The next step will be to provide training for doctors and nurses on how to use it and then to find where the drug is needed. During the test, women were given the drug in a hospital. But researchers are looking for easier ways to use the drug so it can be more widely used in small clinics and the countryside.

同类题4

阅读材料,完成下列小题

未来网络用灯光

    ①未来,网络或许是这样:只要有灯光的地方,你就可以上网,甚至能看高清视频。这就是Lifi——一种利用可见光来传输我们需要的信息和数据的技术,又被称为可见光通信(VLC)。

    ②Lifi拥有很多特有的优点:兼具照明、通信和控制功能——具有能耗低、购置设备少等优势;无电磁污染——适用于飞机、医院、工业控制等射频敏感领域;绿色环保、方便快捷——无须无线电频率许可,无须开挖管道的市政许可,便携性强,便于维护,适合在智能家居、智能交通等领域应用;适合水下通信——基于蓝绿光LED灯的半导体照明技术可用于水下高带宽通信;具有更大的带宽潜力——未来能够达到每秒几百兆甚至更高的接入速度。Lifi作为一种照明和通信结合的新型模式可以有效推动下一代照明和接入网的发展和技术进步,已成为国内外竞争的焦点和制高点。

    ③回顾Lifi的发展历程,早在2000年,日本研究者就提出并仿真了利用LED照明灯作为通信基站进行信息无线传输的室内通信系统。近年来,美国关于VLC技术也开展了许多项目,例如2008年10月的美国国家科学基金重点资助VLC无线通信技术研究。值得一提的是,就在2013年10月11日,英国交付了第一台Lifi技术的产品。在这一个领域,中国并没有落后。几乎就在英国做出产品的同一时期,我们团队也研发出了样机,演示了高清视频流传输。就传输速率而言,我们团队在____年就研发出了____Gb/s的离线数据传输速率,这个速率发布时打破了当时的世界纪录___Gb/s。

    ④目前,限制Lifi系统传输速率提高的主要原因在于白光LED有限的调制带宽。另外,从产业发展而言,已有的Wifi、3G等技术都有着相应的成熟的集成芯片,但可见光通信没有任何专业芯片。虽然Lifi还存在着许多问题和不足,要像Wifi那样走进千家万户,也还有很长的路要走,但这一新兴领域已经展现出蓬勃的生命力。

    ⑤发展LED可见光通信技术,不仅为LED产业可持续发展提供一剂强心剂,还可望拉动上下游整个产业链。

(选自2014年5月22日《光明日报》,有删改)