赔率组合的奥妙

2018年12月01日 22:23 来源:石家庄新闻网

63 The intention is to work and prove the Patent by collective instead of individual aid as less hazardous at first and more advantageous in the result for the Inventor, as well as others, by having the interest of several engaged in aiding one common object—the development of a Great Plan. The failure is not feared, yet as perfect success might, by possibility, not ensue, it is necessary to provide for that result, and the parties concerned make it a condition that no return of the subscribed money shall be required, if the Patents shall by any unforeseen circumstances not be capable of being worked at all; against which, the first application of the money subscribed, that of securing the Patents, affords a reasonable security, as no one without solid grounds would think of such an expenditure.

Mongolfier’s next balloon was spherical, having a capacity of 52,000 cubic feet. It was made from water-proofed linen, and on September 19th, 1783, it made321 an ascent for the palace courtyard at Versailles, taking up as passengers a cock, a sheep, and a duck. A rent at the top of the balloon caused it to descend within eight minutes, and the duck and sheep were found none the worse for being the first living things to leave the earth in a balloon, but the cock, evidently suffering, was thought to have been affected by the rarefaction of the atmosphere at the tremendous height reached—for at that time the general opinion was that the atmosphere did not extend more than four or five miles above the earth’s surface. It transpired later that the sheep had trampled on the cock, causing more solid injury than any that might be inflicted by rarefied air in an eight-minute ascent and descent of a balloon.

63 The intention is to work and prove the Patent by collective instead of individual aid as less hazardous at first and more advantageous in the result for the Inventor, as well as others, by having the interest of several engaged in aiding one common object—the development of a Great Plan. The failure is not feared, yet as perfect success might, by possibility, not ensue, it is necessary to provide for that result, and the parties concerned make it a condition that no return of the subscribed money shall be required, if the Patents shall by any unforeseen circumstances not be capable of being worked at all; against which, the first application of the money subscribed, that of securing the Patents, affords a reasonable security, as no one without solid grounds would think of such an expenditure.

The brothers intended originally to get 200 square feet of supporting surface for their glider, but the impossibility of obtaining suitable material compelled them to reduce the area to 165 square feet, which, by the Lilienthal tables, admitted of support in a wind of about twenty-one miles an hour at an angle of three degrees. With this glider they went in the summer of 1900 to the little settlement of Kitty Hawk, North Carolina, situated on the strip of land dividing Albemarle Sound from the Atlantic. Here they reckoned on obtaining steady wind, and here, on the day that they completed the machine, they took it out for trial as a kite with the wind blowing at between twenty-five and thirty miles an hour. They found that in order to support a man on it the glider required an angle nearer twenty degrees than three, and even with the wind at thirty miles an hour they could not get down to the planned angle of three degrees. Later, when the wind was too light to support the machine with a man on it,153 they tested it as a kite, working the rudders by cords. Although they obtained satisfactory results in this way they realised fully that actual gliding experience was necessary before the tests could be considered practical.

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On October the 12th, 1897, the first trials of this ‘Avion’ were made in the presence of General Mensier, who admitted that the machine made several hops above the ground, but did not consider the performance as one of actual flight. The result was so encouraging, in spite of the partial failure, that, two days later, General Mensier, accompanied by General Grillon, a certain Lieutenant Binet, and two civilians named respectively Sarrau and Leaute, attended for the purpose of giving the machine an official trial, over which the great controversy regarding Ader’s success or otherwise may be said to have arisen.

Other notable designs of these early days were the ‘R.E.P.’, Esnault Pelterie’s machine, and the Curtiss-Herring biplane. Of these Esnault Pelterie’s was a monoplane, designed in that form since Esnault Pelterie had found by experiment that the wire used in bracing offers far more resistance to the air than its dimensions would seem to warrant. He built the wings of sufficient strength to stand the strain of flight without bracing wires, and dependent only for their support on the points of attachment to the body of the machine; for the rest, it carried its propeller in front of the planes, and both horizontal and vertical rudders at the stern—a distinct departure from the Wright and similar types. One wheel only was fixed under the body where the undercarriage exists on a normal design, but light wheels were fixed, one at the extremity of each wing, and there was also a wheel under the tail portion of the machine. A single lever actuated all the controls for steering. With a supporting surface of 150 square feet the machine weighed 946 lbs., about 6.4 lbs. per square foot of lifting surface.

Thus, to the end of the 1901 experiments, Wilbur Wright provided a fairly full account of what was accomplished; the record shows an amount of patient and painstaking work almost beyond belief—it was no question of making a plane and launching it, but a business of trial and error, investigation and tabulation166 of detail, and the rejection time after time of previously accepted theories, till the brothers must have felt that the solid earth was no longer secure, at times. Though it was Wilbur who set down this and other records of the work done, yet the actual work was so much Orville’s as his brother’s that no analysis could separate any set of experiments and say that Orville did this and Wilbur did that—the two were inseparable. On this point Griffith Brewer remarked that ‘in the arguments, if one brother took one view, the other brother took the opposite view as a matter of course, and the subject was thrashed to pieces until a mutually acceptable result remained. I have often been asked since these pioneer days, “Tell me, Brewer, who was really the originator of those two?” In reply, I used first to say, “I think it was mostly Wilbur,” and later, when I came to know Orville better, I said, “The thing could not have been done without Orville.” Now, when asked, I find I have to say, “I don’t know,” and I feel the more I think of it that it was only the wonderful combination of these two brothers, who devoted their lives together for this common object, that made the discovery of the art of flying possible.’

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Chinese President Xi Jinping, Russian President Vladimir Putin and Indian Prime Minister Narendra Modi agreed to strengthen coordination, build consensus and increase cooperation among their countries to jointly promote world peace, stability and development.

A series of actual measurements of lift and drift of the machine gave astonishing results. ‘It appeared that the total horizontal pull of the machine, while sustaining a weight of 52 lbs., was only 8.5 lbs., which was less than had been previously estimated for head resistance of the framing alone. Making allowance for the weight carried, it appeared that the head resistance of the framing was but little more than fifty per cent of the amount which Mr Chanute had estimated as the head resistance of the framing of his machine. On the other hand, it appeared sadly deficient in lifting power as compared with the calculated lift of curved surfaces of its size ... we decided to arrange our machine for the following year so that the depth of curvature of its surfaces could be varied at will, and its covering air-proofed.’

‘However, there is another way of flying which requires no artificial motor, and many workers believe that success will come first by this road. I refer to the soaring flight, by which the machine is permanently sustained in the air by the same means that are employed by soaring birds. They spread their wings to the wind, and sail by the hour, with no perceptible exertion beyond that required to balance and steer themselves.163 What sustains them is not definitely known, though it is almost certain that it is a rising current of air. But whether it be a rising current or something else, it is as well able to support a flying machine as a bird, if man once learns the art of utilising it. In gliding experiments it has long been known that the rate of vertical descent is very much retarded, and the duration of the flight greatly prolonged, if a strong wind blows up the face of the hill parallel to its surface. Our machine, when gliding in still air, has a rate of vertical descent of nearly 6 feet per second, while in a wind blowing 26 miles per hour up a steep hill we made glides in which the rate of descent was less than 2 feet per second. And during the larger part of this time, while the machine remained exactly in the rising current, there was no descent at all, but even a slight rise. If the operator had had sufficient skill to keep himself from passing beyond the rising current he would have been sustained indefinitely at a higher point than that from which he started. The illustration shows one of these very slow glides at a time when the machine was practically at a standstill. The failure to advance more rapidly caused the photographer some trouble in aiming, as you will perceive. In looking at this picture you will readily understand that the excitement of gliding experiments does not entirely cease with the breaking up of camp. In the photographic dark-room at home we pass moments of as thrilling interest as any in the field, when the image begins to appear on the plate and it is yet an open question whether we have a picture of a flying machine or merely a patch of open sky. These slow glides in rising current probably hold out greater hope of extensive practice than any other method164 within man’s reach, but they have the disadvantage of requiring rather strong winds or very large supporting surfaces. However, when gliding operators have attained greater skill, they can with comparative safety maintain themselves in the air for hours at a time in this way, and thus by constant practice so increase their knowledge and skill that they can rise into the higher air and search out the currents which enable the soaring birds to transport themselves to any desired point by first rising in a circle and then sailing off at a descending angle. This illustration shows the machine, alone, flying in a wind of 35 miles per hour on the face of a steep hill, 100 feet high. It will be seen that the machine not only pulls upward, but also pulls forward in the direction from which the wind blows, thus overcoming both gravity and the speed of the wind. We tried the same experiment with a man on it, but found danger that the forward pull would become so strong, that the men holding the ropes would be dragged from their insecure foothold on the slope of the hill. So this form of experimenting was discontinued after four or five minutes’ trial.

‘If I talked a lot,’ said Wilbur Wright once, ‘I177 should be like the parrot, which is the bird that speaks most and flies least.’ That attitude is emblematic of the majority of the early fliers, and because of it the record of their achievements is incomplete to-day. Ferber, for instance, has left little from which to state what he did, and that little is scattered through various periodicals, scrappily enough. A French army officer, Captain Ferber was experimenting with monoplane and biplane gliders at the beginning of the century—his work was contemporary with that of the Wrights. He corresponded both with Chanute and with the Wrights, and in the end he was commissioned by the French Ministry of War to undertake the journey to America in order to negotiate with the Wright Brothers concerning French rights in the patents they had acquired, and to study their work at first hand.

Sulphuric acid and iron filings were used by Charles325 for filling his balloon, which required three days and three nights for the generation of its 14,000 cubic feet of hydrogen gas. The inflation was completed on December 1st, 1783, and the fittings carried included a barometer and a grapnel form of anchor. In addition to this, Charles provided the first ‘ballon sondé’ in the form of a small pilot balloon which he handed to Mongolfier to launch before his own ascent, in order to determine the direction and velocity of the wind. It was a graceful compliment to his rival, and indicated that, although they were both working to the one end, their rivalry was not a matter of bitterness.

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Tanzanian President John Magufuli thanked China for the 41-million-U.S.-dollar project located in the University of Dar es Salaam at the handover ceremony.

Langley Memoir on Mechanical Flight, Smithsonian Institution, Washington.

Let it not be thought that in this comment there is any desire to derogate from the position which Ader should occupy in any study of the pioneers of aeronautical enterprise. If he failed, he failed magnificently, and if he succeeded, then the student of aeronautics does him an injustice and confers on the Brothers Wright an honour which, in spite of the value of their work, they do not deserve. There was one earlier than Ader, Alphonse Penaud, who, in the face of a lesser disappointment than that which Ader must have felt in gazing on the wreckage of his machine, committed suicide; Ader himself, rendered unable to do more, remained content with his achievement, and with the knowledge that he had played a good part in the long search which must eventually end in triumph. Whatever the world might say, he himself was certain that he had achieved flight. This, for him, was perforce enough.

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