（血管） in the brain, which brings on a headache. Stress can cause them or make them worse. It’s also common for your muscles to tense up when you’re stressed, which can also cause a headache.
WHAT TO DO:
If you don’t want to take medicine, try spreading lavender （薰衣草） oil on your temples（太阳穴）when a headache starts. Or try one of these home remedies for headaches.
Stress can make you mentally sick, too. Too much of the stress hormone cortisol （皮质醇）can make it harder to concentrate, causing memory problems as well as anxiety or depression, says Dr. Levine.
WHAT TO DO:
Relax until you regain your concentration. Practice closing your eyes and breathing in and out slowly, concentrating only on your breath.
Losing a few strands of hair is normal (old hair follicles （囊）are replaced by new ones over time), but stress can disturb that cycle. Significant stress pushes a large number of hair follicles into what’s called a resting stage and then a few months later those hairs fall out, according to MayoClinic.org. Stress can also cause the body’s resistant system to attack your hair follicles, resulting in hair loss.
9
WHAT TO DO:
Be patient. Once your stress level returns to normal, your hair should start growing back.
60. If you’re stressed, you might have one of the following symptoms EXCEPT that ______.
A. you keep getting headaches
C. your hair is falling out
61. Which of the following is suggested if your brain goes out of focus? A. B. C. D.
62. What will happen once we get over our stress according to the passage? A.
Our hair starts falling out and then grows back. Relaxing and attacking your brain softly. Spreading lavender oil on your temples. Waiting until your brain returns to normal. Breathing slowly with your eyes closed.
D. your brain feels confused B. you always have a cold
10
B. C. D.
Our body’s resistant system attacks your hair follicles Our hair starts growing again.
A serious headache starts.
(C)
For many in the general public and the engineering community alike, the potential implications of additive manufacturing (AM) have excited the imagination. Popularly known as 3-D printing, the emerging class of technologies has been regarded as both a revolution in production and an
opportunity for dramatic environmental advance.
Yet while the technological capabilities of additive manufacturing processes are studied extensively, a deep understanding of their environmental implications is still lacking.
A new special issue of Yale’s Journal of Industrial Ecology presents the cutting-edge research on this emerging field, providing important insights into its environmental, energy, and health impacts.
Though sometimes described in the public field as similar to an inkjet printer for making objects, additive manufacturing is primarily used as a production process in industry and contains a diverse set of technologies. What they share is the ability to produce products and parts based on digital information by adding layers of materials one after the other rather than, as in traditional manufacturing, removing materials – thus the label “additive.”
“The research in this issue shows that it is too early to label 3-D printing as the path to sustainable manufacturing,” said Reid Lifset, editor-in-chief of the Journal of Industrial Ecology and co-author of the lead editorial. “We need to know much more about the material footprints, energy consumption in production, process emissions, and especially the linking devices and adjustments between the various stages in the production process.”
Additive manufacturing is sometimes seen as inherently environmentally preferable to traditional manufacturing because of its potential for local production – by consumers,
11
merchants and hobbyists – and because it is thought to allow zero-waste manufacturing. Research in this issue, however, indicates that the environmental performance is very sensitive to the pattern of usage and composition of the machinery and the materials used.
“This special issue demonstrates the capability of industrial ecology to reveal important and often overlooked aspects of new technologies,” said Indy Burke, Dean of the Yale School of Forestry & Environmental Studies. “If we are to realize the environmental potential of 3-D printing, we need to know where the challenges and the advantages lie.” The special issue contains:
examination of the sustainability benefits derived from the complex figure of parts enabled by the technology
analysis of supply-chain issues arising from the use of the technology studies of operator exposure to printer emissions and dangerous materials investigations of the process energy consumption of AM technologies life cycle assessments (LCA) of AM processes and products
63. The word “additive” in the passage refers to ______.
A. the substance added in small amounts for a special purpose
B. the additional technological capabilities of manufacturing processes C. the digital way to produce products by adding serial layers of materials D.
64. The contents listed in the special issue mentioned at the end of this passage focus on ______.
12
the traditional way to produce products by removing materials
相关推荐：
loading