For a standard external involute spur gear, [图], ...

For a standard external involute spur gear,, standard center distance,transmission ratio, try to determine number of teeth, diameter of refference circle, diameter of addedum circle, diameter of dededum circle, tooth height, tooth thicknessand space width.

For a standard external involute spur gear,,(1) find standard center distance, base circleaddemdum circlepitch of base circle . (2) use scale ofto draw therectical meshing line, actual meshing line, pitch circles of gear 1 and gear 2 , and meshing angle. ( driving gear 1 rotates clockwise) (3) calculate contact ratioby measuring the length in above figure and label double teeth meshing zone and single tooth meshing zone. (4) determine whether this gear pair can transmit motion continuously? why?

After the order\

A.the gearbox

B.the steering gear

C.the turning gear

Known: direction of gear 1,,,, find:and(magnintude and direction).

(c) Acting as an external consultant to Semer, discuss the validity of the proposed strategy to increase gearing, and explain whether or not the estimates produced in (b) above are likely to be accurate. (10 marks)

The lube oil pump used in a diesel engine is a _____.

A.volute pump

B.centrifugal pump

C.diaphragm pump

D.gear pump

After the order “_____” is given, the air system is shut down, the turning gear put in, all drains and indicator cocks opened, and the cooling water and lubricating oil systems kept running.

A.Stand-by Engine

B.Stop Engine

C.Finished With Engine

D.Dead Slow Ahead

听力原文： The US Art Auction house Sotbeby's is gearing up for one of its biggest sales of the year, an auction of impressionist and modern art to be held this week. It' s expected to fetch a total of around $180 million. Sotheby's may hold an auction twice a year but this time there's a real buzz about proceedings. There are 55 major works up for grabs but all the attention is on this one--Claude Monet' s "Jeune File Dan Le Jardin" painted in 1880. It's expected to fetch some $ 30 million. The organizers said it' s one of the last great paintings of Monet that's every likely to come onto the market. Not just painting, but sculpture is also on offer.

What is the news item mainly about?

A．Modern Lt.

B．Art exhibition.

C．Sales of art works.

D．Famous paintings.

1. Each is creating a huge archipelago of interconnected products and services. What is each company creating? 2. It's about velvet handcuffs: making it easy for you to embrace its offerings and as hard as possible to switch to a rival's. Why is it called a velvet handcuff? 3. Apple is the most closed. How is Apple’s system? 4. Microsoft Office is available for just about anything with a screen, as are many of its mobile apps. What Microsoft products and services can we get for our smartphones? 5. You, the consumer, should be delighted by this direction. What are the customers happy about?

听力原文： NASA is examining photos of Space Shuttle Endeavour after discovering what appears to be damage to a critical heat protection tile. Ice is believed to have broken off the external fuel tank during lift-off and struck the shuttle.

NASA wants to study the problem before choosing a course of action. Photos taken of Endeavour's belly by the crew of the International Space Station shows a three-inch-by-three-inch gouge in at least one black heat tile under the shuttle's right-hand wing near one of the main landing gear doors. NASA's John Shannon says if the damage is life-threatening and too extensive to repair, a rescue shuttle could be sent to save the astronauts.

NASA runs such analysis every single flight. Up to now, Space Shuttle Endeavour has at least 68 days of consumables to support ten crew members and NASA can get a shuttle ready by October 5th.

Repair options include a heat resistant paint, a protective plate that could be screwed into the gouge place or a thick compound that can be squirted.

Where is the damage gouge located in Space Shuttle Endeavour?

A．In one black heat tile under the right wind.

B．In one of the main landing gear doors.

C．In one black heat tile under the left wind.

D．In the middle of Endeavour's belly.