问题 问答题 简答题

管子弯曲半径的怎样确定?

答案

参考答案:根据技术设计要求及管子设备加工能力,采用弯曲半径R=3D。在管子布置比较紧凑的地方,允许小于三倍,但不得小于2倍。管子有特殊要求的弯曲半径,经过有关部门研究认证,才可做特殊胎具,专项专用。小于2倍弯曲半径的管子,应采用定型弯头。大于3倍弯曲半径的大弯曲半径,可以采用将大半径弧长按对应角度分段,用R=3D小弯曲半径弯曲等方法解决。

单项选择题
单项选择题

For more than a decade, the prevailing view of innovation has been that little guys had the edge. Innovation bubbled up from the bottom, from upstarts and insurgents. Big companies didn’t innovate, and government got in the way. In the dominant innovation narrative, venture-backed start-up companies were cast as the nimble winners and large corporations as the sluggish losers.

There was a rich vein of business-school research supporting the notion that innovation comes most naturally from small-scale outsiders. That was the headline point that a generation of business people, venture investors and policy makers took away from Clayton M. Christensen’s 1997 classic, The Innovator’s Dilemma, which examined the process of disruptive change.

But a shift in thinking is under way, driven by altered circumstances. In the United States and abroad, the biggest economic and social challenges—and potential business opportunities—are problems in multifaceted fields like the environment, energy and health care that rely on complex systems.

Solutions won’t come from the next new gadget or clever software, though such innovations will help. Instead, they must plug into a larger network of change shaped by economics, regulation and policy. Progress, experts say, will depend on people in a wide range of disciplines, and collaboration across the public and private sectors.

"These days, more than ever, size matters in the innovation game," said John Kao, a former professor at the Harvard business school and an innovation consultant to governments and corporations. In its economic recovery package, the Obama administration is financing programs to generate innovation with technology in health care and energy. The government will spend billions to accelerate the adoption of electronic patient records to help improve care and curb costs, and billions more to spur the installation of so-called smart grids that use sensors and computerized meters to reduce electricity consumption.

In other developed nations, where energy costs are higher than in the United States, government and corporate projects to cut fuel use and reduce carbon emissions are further along. But the Obama administration is pushing environmental and energy conservation policy more in the direction of Europe and Japan. The change will bolster demand for more efficient and more environmentally friendly systems for managing commuter traffic, food distribution, electric grids and waterways.

These systems are animated by inexpensive sensors and ever-increasing computing power but also require the skills to analyze, model and optimize complex networks, factoring in things as diverse as weather patterns and human behavior. Big companies like General Electric and IBM that employ scientists in many disciplines typically have the skills and scale to tackle such projects.

Big companies have the advantage of()

A. making Complex networks work in a coordinated way

B. reducing the cost by producing things in large quantities

C. being able to integrate innovations across complex systems

D. controlling human behavior with imposed restraints on creativity