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By Louis G. Bailey

This paper .reviews some of the key developments which have been made in the synthesis of the III-V compound semiconductors and the associated progress in obtaining high-quality material for device development. The history of the investigation of the semi-conducting properties of these materials has indicated the need for synthesis techniques capable of producing rnaterial of high chemical purity and physical perfection. The progress in the area is described, and the present status of quality of several compounds is discussed. In addition, recent studies of localized epitaxial deposition of GaAs into semi-insulating GaAs substvates for the development of arrays of devices ave reviewed. In conclusion, some important areas for future research and developrnent are discussed. INTEREST in III-V compounds as semiconductors dates back to the period 1950 to 1952, when Goryunova, Ioffe, and, in particular, Welker determined that 111-V compounds were structural analogs of the group IV elements carbon, silicon, germanium, and tin and that they were also semiconductors.'-3 Since that time interest in the properties of these materials has ex- panded rapidly. During 1953 and 1954, the first reports of rectification, photoconductivity, and optical absorption in these materials came from several investigators. In 1955, recombination radiation from samples of GaAs, InP, and GaSb was reported by ~raunstein .' This radiation was produced by injected minority carriers from point and large-area contacts. From 1955 to 1960, efforts increased on preparing large, pure specimens of these materials for the study of basic physical phenomena and device exploration. By 1960, materials preparation and the understanding of the physics of some of the materials had advanced to where some very interesting and potentially useful phenomena came under study. The first observation of electric-field-induced changes in the optical absorption edge (Franz -Keldysh effect) of 111-V compounds was reported for GaAs by Moss in 1961.' In 1962 the study of recombination radiation advanced rapidly. Keyes and Quist6 and Pankove and Berkey-heiser7 reported high radiative efficientices obtained from recombination, and then the first injection electroluminescent lasers in GaAs were announced by Hall ef al.,' by Nathan et al.,O and by Quist ef al.,'O and in Ga(As, P) alloys by Holonyak and Bevacqua." Hil-sum has reviewed the early work leading to the first observations of laser action in GaAS." Recombination processes in GaAs, Gap, and the other 111-V com-

Jan 1, 1968

By John Johnston

ONLY two of the Institute's 26 Local Sections were unrepresented at the delegates' three sessions, held on Monday morning and afternoon and Thursday afternoon of the annual meeting. The Philadelphia and Wyoming Sections alone sent no delegates. In all, seven hours were spent most profitably in reviewing the work done by the Institute at headquarters and in the field, comparing ideas and practices in varied activities, and in establishing personal contacts. Cordiality and the co¬operative spirit marked the meeting and apparently no one had any serious grievances to air. Four motions were introduced and unanimously passed. The first, which was introduced by B. L. Sackett, was a recommendation by the delegates that a national committee be appointed to cooperate with Local Sections in the matter of student activities, to promote Institute welfare. It was agreed that this recommendation be made simultaneously to the Board of Directors and to the Mineral Industry Education Division. A subsequent resolution by A. M. Smith was passed asking that a part of the duties of this committee be to secure the opinions of Local Sections as to the most desirable methods of interesting students in the preparation of technical papers, by giving prizes or otherwise, and to report their findings at the Section Delegates' meeting next year.

Jan 1, 1933

By AIME AIME

THE Institute of Metals Division of this Institute held a joint meeting with the American Foundry- men's Association on Oct. 5-9, at Syracuse, N. Y. The registration at this meeting was about 150. There were four meetings in all, three of which were in con- junction with the American Foundrymen's Association. This combination works out very nicely and gives the I Division a number of practical foundry papers that it would not get otherwise. The sessions were well attended and the discussion was active. The session on Monday morning was of a general nature and consisted of the following subjects : " Refractory Problems in the Non-ferrous Electric Furnace Casting Shop, " "Temperature Control of Non-ferrous Alloys," "Atomized Coal System of Non-ferrous Melting," "Material Handling in a Brass Foundry." On Tuesday morning, the session was on "Aluminum and Its Alloys." The paper on permanent mold castings created a large amount of discussion, in fact so much that it had to be renewed after the close of the regular program. Aluminum is assuming a more important place every year and adds greatly to the program as a whole. One of the most remarkable meetings that this Division has ever had was held on Tuesday at noon in the form of a Round Table discussion, headed by G. K. Elliott, chairman of the Division, Cincinnati, Ohio. Mr. Elliott divided the members present, numbering about 80, into groups as they were seated at the tables. Each of these groups suggested a topic for discussion. They were as follows : "Fluxes on Market ;" "Simplification of Alloys;" "Pyrometric Control;" "Effect of Gas- sing Metal and Control;" "Barium Sulfate Added to Electric Furnace to Create Slight Oxidation to Remove Aluminum and Silicon;" and" Nickel in Brass."

Jan 1, 1925

By Edward I. Salkovitz

THE determination of the orientation of metal single crystals and the studies of plastic deformation are greatly facilitated by the use of the stereographic projection. To draw a standard projection of the crystal it is necessary to have a tabulation of the angles between the various crystal-lographic planes of the particular crystal studied. Bozorth' has published such a table for the cubic system which can be found in many reference books; such convenient tabulation for the hexagonal metals, however, does not appear to be in the literature, although scores of workers have calculated these angles. Therefore, Table I of angles for magnesium, zinc, and cadmium has been compiled. Since the c/a ratio is different for each of these metals, three separate calculations are necessary. The angles 4 between (HKIL) and (hkil) were calculated by means of the formula: Hh+Kk+½(Hk + hK)1+~3aLl cos The c/a ratios were calculated from data given in the 1948 edition of Metals Handbook. Fig. 1 is a typical (0001) standard projection of zinc. For all practical purposes, it serves for cadmium as well, as can be seen from the table. For magnesium, however, it is necessary to construct another net. R. M. Bozorth: Physical Review. (1925) 26, 390.

Jan 1, 1952

By Thomas T., Read

THROUGHOUT the Colonial era, Philadelphia was easily , the leading city of North America, and it still held that position at the end of the period, with a population of about 25,000, though closely pressed by Boston, which had slightly over 20,000, and New York, which had nearly as many. It was the center of a region in which mineral industry was important. Thomas Rutter's bloomery, built in the Schuylkill valley in 1716, was quickly followed by many others, and during the Colonial period at least 20 blast furnaces, 45 forges, and iron- works of other types were built in eastern Pennsylvania, which easily led all the other colonies in iron manufacture. During the Revolutionary period others were erected as far west as Fort Loudon, in the Cumberland c alley.^ After 1800 the rapid development of the anthracite mining industry profoundly affected Philadelphia's, development, since transportation of the coal was then necessarily by water, and the streams of the anthracite . regions mostly flowed into either the Schuylkill or the Delaware Rivers. With an abundant near-by supply of coal and iron, with the seat of government, which had been there since 1774, and with a National Bank established there in 1791, one would have seemed safe in prophesying, at the beginning of the nineteenth century, that Philadelphia would permanently remain the leading city of the United States. Education in Philadelphia was at first wholly in the hands of the Quakers, who had established a "Public School" there in 1689, but in November 1739 George Whitefield, who had created a sensation in England by his preaching, though only 24 years old, passed through Philadelphia on his way to Georgia to found an orphan school there. He preached a series of sermons in Christ Church that were so disturbing to the established church that on Nov. 25 the Rev..Richard Peters (who was also Provincial

Jan 1, 1941

By Frances H. Clark

IN a concern with the varied interests of the Western Union Telegraph Co., where practically all types of metals, both ferrous and nonferrous, are utilized, many types of failures of materials occur. These have to do not only with outside plant construction, such as corrosion and fatigue of line wire and cable, but also with inside plant equipment operating at such high speeds that rapid deterioration of metal. parts due to fatigue and wear results. Both corrosion and fatigue affect the life of copper wire so its normal life in any particular locality is largely dependent on the atmospheric conditions. Tensions vary widely owing to changes in temperature and ice and wind loadings and the wire is Subject to a great range of vibration caused by wind gusts aril vibration front trains or other heavy vehicles transmitted through the earth. High frequency low-amplitude vibrations are sometimes audible as singing in the wire. The other extreme is the vertical slashing or dancing of the wire observed during severe storms where amplitudes of 9, ft. or more at low frequencies have been observed.

Jan 1, 1942

(Under this heading will be published notes sent to the Secretary of the Institute by members or other persons introduced by members.) Mining Engineer. Graduate of Colorado School of Mines, 1912, experienced in coal, lead manganese and limestone mining, wishes execu¬tive position. A-2146. Graduate Mining Engineer.-Discharged, reserve officer, age 32, single, 7 years' experience holding responsible executive positions, in iron, copper, and talc mining. Well recommended. A-4913. Mine Manager, Superintendent or Engineer. Age 41, graduate of Michigan College of Mines; 20 years' experience in responsible positions in connection with large operations; in iron, copper, pyrites, lead and zinc mines; successful in finding and developing orebodies, increasing production, and reducing costs. Desires a position with a future. A-4081. Mining Engineer.-Graduate from Polytechnicum, Stockholm; 14 years' practical experience in Sweden, United States, Belgium, and Spain, in iron-ore development, mining, and milling; thorough knowledge of English, French and Spanish; desires position as superintendent or assistant manager. Good references; member; now in Sweden. A-4914. Research Engineer. Now in Chile on the erection of a 50-ton mill with modern machinery for the treatment of Chilean nitrate. Desires connection from the first of next year; with firm operating in South or Central America. A-4915. Metallurgical Engineer. Junior member, age 26, single, graduate Columbia School of Mines; recently discharged as lieutenant in the heavy artillery. A-4916. General Superintendent. Technical graduate, age 35, desires position over a group of four or five mines or as assistant general superintendent for a large. company. Has had experience in superintending mines, construction work, opening new and abandoned mines, safety and effi-ciency engineering and handling organized labor. At present employed by a coal company in the middle West. A-4917.

Jan 11, 1919

By Walter W. R. May

FOR more than 25 years a few business men who represent virile private enterprise in the Pacific Northwest have been trying to awaken the community to the potential benefits of an open Columbia River. No threat of government com- petition then hung over the industry, which was adjusted to state regulation. Numerous sites were engineered and the findings were laid before the operators of heavy industry in the East, Middle West, and South -even of Europe. These engineering data became, if not the basis, the inspiration upon which the U. S. Army Engineers eventually were to "build the Columbia River Bible" - their great document known as House Document 103, the report on the Columbia River and minor tributaries.

Jan 1, 1940

By Shiou-Chuan Sun

THE fact that coals of different ranks and even of the same rank differ greatly in their amenability to froth flotation is well known. In recognition of the need for an explanation of this phenomenon, two hypotheses have been suggested. Wilkins1 reported that the floatability of coals increased with an increase of the carbon content or rank. This postulate is handicapped by the fact that bituminous coals that possess moderate carbon contents are actually more floatable than anthracite coals that have high carbon contents, as shown in columns 6 and 9 of Table I. Taggart and his associates' implied that the difference of floatability between bituminous and anthracite coal was caused by the variation of carbon-hydrogen ratio. This is not applicable to the relative floatability of other coals and carbons. For example, column 11 of Table I shows that the carbon-hydrogen ratios of low-floating lignitic coal and non-floating animal charcoal are not only smaller than the moderate-floating anthracite coal, but are also similar to the high-floating bituminous coal. Furthermore, according to this hypothesis, high temperature coke-A (464), Ceylon graphite (1238), and lamp-black (357), all possessing extremely high carbon-hydrogen ratios, should be less floatable than other substances having much lower carbon- hydrogen ratios such as high volatile-B bituminous coal (11.9 to 22), anthracite coal (35.7 to 60.5), lignitic coal (15.6 to 33.6), and charcoal (13 to 26.2). However the former group is actually more floatable than the latter group.

Jan 1, 1954

By William F. Boericke

THE Christy Creek clay mine of the General Refractories Co., in the Olive Hill District, ranks with the most important producers in the north-eastern Kentucky fire clay field, both from production of high-grade flint clay, as well as unusual extent and thickness of deposit. The property is but one of a number controlled by the General Refractories Co. in this district, but is given first consideration among them by the operating staff. Its total area is over 5000 acres, owned in fee or by lease of clay mining rights, and although mining operations have been in progress for over five years, scarcely one per cent of the ground has been worked as yet. The mine is near the southwestern end of the clay field, which extends in a belt 12 miles wide and 55 miles long, in a southwestern direction from Kenova, W. Va., which, as the name indicates, is at the junction of Kentucky, Ohio, and West Virginia. Olive Hill, where there is one of the l1Ulin plants of the General Refractories Co., and to which the clay from the mine is shipped, is about 26 miles distant from the mine. Connection is made with the Chesapeake & Ohio R. R. by a spur line . 8 miles in length, owned and operated by the company.

Jan 1, 1929

By AIME AIME

Award of a Gold Medal : to the Institute. The Jury of Awards of the Jamestown Ter-Centennial Exposition has conferred a gold medal, the highest distinction within its power,. on the American Institute of Mining Engineers for the excellence of its publications during the past decade. ; A half-tone photographic reproduction of both sides of the medal is given in the accompanying illustration.

Jan 7, 1908

By T. A. Rickard

Freeman, the English historian, said that he had learned from Macaulay "never to be afraid of using the same word or name over and over again if by that means anything could be added to clearness or force. Macaulay never goes on, like some writers, talking about `the former' and `the latter', `he', `she', `it', and `they', through !clause after clause, while his reader has to look back to see which of several persons it is that is so darkly referred to". He might have learned also from Macaulay that a preposition makes a' feeble ending for a serious statement. How often do you hear `the former' and `the latter' in conversation? Good conversation is a guide not to be dis¬dained. When you must use `the latter', do not confuse it with `the last'. Cheap labor, cheap fuel, and cheap transport are essential, the latter [last] being particularly important in base-metal mining. The apparatus may be used to determine such gases as hydrogen sulphide, chlorine, oxides of nitrogen and some others, as well as sulphur dioxide. In the case of the latter two, etc. The two last mentioned are "sulphur dioxide" and "some others". He should have stated which two, and he should have avoided that wretched phrase "in the case of ". Pinning may be partly prevented by use of chalk, oil, or turpentine. The latter [last] is best. I "Partly prevented" is a poor phrase. `Prevented! is a word that does not lend itself readily to modification. He means `checked' or `corrected'.

Jan 1, 1931

By D. M. Clippinger, J. J. Eidel, J. E. Frost

At Ithaca Peak, one of three peaks situated on Duval Corporation's Mineral Park property, a 'Single pulse of quartz monzonite magma intruded the isoclinally folded Precambrian Cerbat complex consisting of schist, quartzfeldspar gneiss, and amphibolite. The magma reacted with the Precambrian rocks, yielding a quartz-diorite rim. As the magma crystallized within the rim, it produced, progressing in'ward, annular bodies of quartz monzonite porphyry, quartz porphyry, and a distinctive quartz porphyry containing abundant podiform, tabular, and irregular quartz masses. These quartz masses are spatially associated with discontinuous crenulate and tabular quartz veinlets. Following crystallization, the Ithaca Peak stock and part of the surrounding Cerbat complex were fractured, producing a stockwork of predominantly northwest and northeast-trending fractures. The stockwork was then mineralized during a period of decreasing temperature by: ( 1) quartz-pyritechalcopyrite veinlets without distinct selvages and with distinct alteration envelopes in which orthoclase was altered to quartz and sericite; (2) quartz-pyrite-chalcopyrite veins and veinlets with distinct selvages and without distinct alteration envelopes; and (3) pyrite-chalcopyrite- galena-sphalerite veins. The Ithaca Peak stock was pervasively sericitized or argillized. The Mineral Park property is surrounded by a zone of propylitization Alteration and mineralization are coextensive in space and were, at least in part, coincident in time. The Mineral Park property possibly was elevated and exposed twice prior to its present exposure. The protore has been enriched by a factor of three. The Ithaca Peak supergene ore body is conformable with present topography and lies above the present water table. The shape of the ore body was controlled by erosion and oxidation of the previously enriched mineralization. Hematite, goethite, and jarosite present at the surface indicate a high primary pyrite environment, but it is possible to recognize that a small proportion of veins and veinlets contained greater amounts of chalcocite and chalcopyrite than pyrite. The igneous facies on Ithaca Peak are the products of differentiation within a solidifying rim according to Bowen's Reaction series. The innermost facies contain more quartz and orthoclase than the outer facies. Late magmatic quartz in the case of Ithaca Peak contains small amounts of pyrite and molybdenite. It is suggested that this quartz-sulfide mineralization, may also have been the product of differentiation the product of differentiation, may indicate that the later hydrothermal mineralization may also have been the product of differentiation.

Jan 1, 1968

By Lendall P. Warriner, Blandford C. Burgess

Jasper County lies just north of the geographical center of Georgia, bounded on the west and north by the Ocmulgee River. The county seat, Monticello, is approximately 65 miles east-southeast of Atlanta and 40 miles north of Macon. It is served by the Macon-Athens branch of the Central of Georgia Railway Co. and by five paved highways converging from adjoining county seats. Farming and lumbering are the principal local occupations. About half the county is covered with pine and mixed hardwoods; a large part of the forested land is owned by the Soil Conservation Service of the Department of Agriculture in its Piedmont Land Utilization Project. The topography is one of gently rolling field and forest with occasional hills rising 100 ft or: more above the creek beds. Though annual rainfall is in the neighborhood of 60 in., most of it falls in torrential downpours of short duration which tend rapidly to erode the red soil and convert the country roads to greasy tracks of red mud.

Jan 1, 1949

By Leo J. Vogel, E. D. Hummer, David J. Akers

INTRODUCTION An efficient refuse-disposal system is a necessary part of the modem cleaning plant. The large-scale refuse system and disposal area, engineered for the lifetime of the plant, has become more important due to the greater tonnages of refuse produced from increased quantities of mechanically mined and prepared coal. Laws and increased government regulations have affected the design and operation of disposal systems. THE EFFECT OF MINE AND PLANT OPERATION Refuse disposal starts at the mining face. The mining system, the type of roof support, the machinery used, and the degree of discipline at the face contribute to the amount and type of refuse that must be removed through the disposal system. Economies gained through modification of the mining system or mining machinery may be partially offset by increased dilution of the mined coal with impurities from associated rock formations. In some cases the change in the mining system and equipment has reduced the dilution. In all cases the ratio of impurities that must be removed from the raw-coal feed to the plant not only affects the maintenance and

Jan 1, 1979

By Sydney H., Ball

ONE of the important mineral discoveries of the eighteenth century was , that of the Minas Geraes, Brazil; diamond fields. The production of this and of .other diamond discoveries in neighboring states made Brazil the premier producer of diamonds, succeeding India; its 140 years of supremacy finally passed to- South Africa- 60 years ago. Three times have diamonds contributed heavily to Portugal's somewhat checkered financial history; first in the sixteenth and seventeenth- centuries when the diamond trade of India was controlled by its citizens residing in ,Goa, later in the late eighteenth and the first 75 years of the nineteenth century when the Brazilian fields were the world's source of diamonds, and now, when the Angola diamond mines are the principal source of revenue of its colony, Portuguese West Africa. Certain phases in the history of the administration of the Brazilian field are sufficiently curious to warrant description.

Jan 1, 1929

By R. S. French, W. R. Hibbard

FOR tensile deformation, if the stress value is defined by the ratio of the load to the actual area, and the strain value by the natural logarithm of the ratio of the immediate length to the original gauge length of the sample, the resulting data when plotted with logarithmic coordinates result in a linear relation extending from the initial plastic yielding through the maximum load and in some cases, such as for copper and brass, to fracture'.'. The normal form of the curve, therefore, is a parabola, satisfying the following equation: S = Kem [1] where S and e represent true stress and strain, K is a constant, and m is a coefficient evaluating the slope of the curve and designated therefore as the strain hardening coefficient. Hollomon² has reported that this coefficient is a function of the yield strength as effected by grain size in alpha brass, and the carbon content and heat treatment of steel. In the case of steel, the value of the proportionality constant is a function of the carbon content. It was further shown in that paper2 and also by Low and Prater -hat, if the power relation between stress and strain remains valid, the strain hardening coefficient m, is equal to the strain at the maximum or necking load. Thus, an added significant feature is that this coefficient may serve as an index of the capacity for deformation prior to localized necking and subsequent fracture, e.g. drawability. The constant K may be defined as the strength of the material at unit strain. Together the K constant and the m coefficient describe an alloy's physical properties as far as strength and ductility are concerned for a particular yield strength and, in the case of steel, a particular carbon content. The work of Lacy and Gensamer4 gives data on alloy ferrites from which very close estimates of the strength of ternary and higher iron alloys have been made. It was the purpose of this investigation to develop similar data for commercial copper base alpha solid solution alloys. Preparation of Specimens Commercial binary alloys of copper with aluminum, beryllium, cadmium, nickel, silicon, tin and zinc were investigated. In addition, laboratory castings were made of a 1 pct silicon alloy and a 2 pct aluminum alloy to complete these particular series. Two types of copper were used, oxygen free OFHC and tough pitch FC. The analyses of these alloys are shown in table I. Standard ASTM sheet tensile specimens were used to determine the usual physical properties of each alloy and to obtain stress data at strains from 0.0005 to 0.01. Small (1/4 in. x 3 in. x tk.) samples

Jan 1, 1951

By L. D. Anderson

IN STUDYING Utah as a lead producing state one is immediately confronted by the fact that few, if any, of the ores of the state are valued for their lead contents alone. More correctly the ores from which this metal is recovered are characterized as silver lead. Even then the whole story is not told for many of these ores carry also gold, copper, zinc, bismuth, antimony, arsenic, tellurium, and other metals. It becomes apparent, therefore, that the production of lead i11 Utah is influenced by many factors. For example, i11 the early part of 1923 there was a marked increase in the production of the lead by reason of the efforts made by silver mines to produce as much silver as possible before the termination of purchases under the Pittinan Act in June, 1923. As nearly all silver ores carried more or less lead the production of that metal was increased with the increase in silver production. Very few, if any, ores of the State are mined for their lead contents alone. Important as Utah's contribution to the lead output of the country is nevertheless it is bound up to some extent with the production of gold, silver and copper.

Jan 1, 1925

By AIME AIME

WILLIAM ("BILL") EMBRY WRATHER, recently elected to a second term as Director of the Institute, is widely known as petroleum geologist, gentleman, and scholar. Born in Brandenburg, Ky., he was early endowed with a Southern accent which has remained with him strongly flavored by his later life in the oil-fields of Texas and the Mid-Continent region, and only thinly concealed by a Middle Western burr acquired during his student days at the University of Chicago. After graduating there with the Ph. B. in 1908, young Wrather (the adjective still fits!) joined the Gulf Production Co. Soon afterwards he married a charming Chicago girl, Alice Dolling, who, with their two daughters, has been his companion on many of his more distant trios.

Jan 1, 1945

By Morris M. Fine, Norwood B. Melcher

It is out of the question, at this time, to select any one prereduction process as superior to the others. It is apparent that several share a basic similarity and that within the groups listed in Part 1, the reduction vessel is sometimes the only significant variable. Claims as to the virtues of one machine over another are difficult to substantiate: one may be rapid, another thermally frugal. Based on published data, however, all seem to be performing adequately. It would appear that processes based on carbonized pellets are most applicable to foundry iron at low production rates. Adaptation to large scale manufacture of blast furnace hot metal or to agglomeration of fine concentrates at the mine site is much less likely.

Jan 8, 1966