Abstract: In an apparatus for crucible-free zone melting, a device for supporting a lower end of the crystalline rod of semiconductor which has a junction with a seed crystal characterized by the support device being formed by a plurality of sections or parts which are moveable relative to each other from a first position spaced or retracted from the seed crystal and the lower end of the rod to enable melting the rod adjacent to the junction and a second position forming a container surrounding the seed crystal and the lower end of the rod for receiving a supporting or stabilizing medium which dampens or prevents vibrations from being applied to the lower end of the rod and the junction. The sections are held in the second position by a holding means which may either be electromagnetic or mechanical.

Abstract: Stock semiconductor crystal rods are zone melt refined by positioning such stock rods in a zone melt environment with a seed crystal attached to a lower end thereof, generating a melt zone at the juncture of the seed crystal and stock rod and controllably moving the melt zone away from the juncture and through the stock rod to a select point thereon, uniformly supporting the cone-shaped lower portion of the rod being refined from below the juncture to an area adjacent the select point so as to prevent vibrations and the like within the rod being processed, applying a controlled electrical current across the melt zone from the ends of the rod being refined and controllably moving the melt zone from the select point through the remainder of the rod. The uniform support is provided by a movable electrically conductive funnel-shaped jacket filled with an electrically conductive stabilizing means, such as metal spheroids or particulate silicon particles, molten metal, etc.

Abstract: Method of quantitatively determining chloromethyl methyl ether and/or bis-chloromethyl ether at greater sensitivity comprising utilizing an alkali metal salt of a lower alcohol and a readily detectable organic hydroxy compound in lower alcohol medium in a salt-to-hydroxy compound molar ratio of from about 0.2:1 to about 5:1 to react, when warmed, with either or both of said ethers, to form derivatives thereof; adding water to the reaction mixture and an immiscible hydrocarbon solvent; agitating and partitioning the mixture and directing at least a portion of the immiscible organic solvent extract onto a suitable gas chromatograph, preferably packed with glass beads with a stationary liquid phase thereon and more preferably with the beads coated with OV275 as the liquid phase; and eluting the reaction product or products off the column and through a detector therefor with an inert gas.

Abstract: A foam generator for foaming liquids having two peripheral disc portions each being connected with a housing with a gas inlet to one of the housings. The housings being connected together with the peripheral disc portions forming a hollow space such that gas fed to the hollow space through the gas inlet enters the hollow space and exits between the peripheral disc portions to form air streams to foam the liquids.

Abstract: An apparatus for the continuous collection of a time-weighted gas sample is disclosed. The apparatus inclues a gas reservoir and an openable and closeable gas flow assembly communicating with the reservoir which assembly allows gas to flow at a constant rate from the exterior of the reservoir to the interior of the reservoir when there is a sufficient gas pressure differential between the exterior and interior of the reservoir so that the passing gas achieves a linear velocity in the throat of the gas flow assembly equal to the velocity of sound in the passing gas in the throat. The apparatus of this invention may also include additional gas sample removal assemblies attached to the reservoir.

Abstract: There is disclosed a technique for growing, from a melt, doped single-crystal fibers for use as lasers or other active or passive optical devices of a size that is compatible with proposed optical fiber communications systems. A rod of undoped material has deposited thereon, by mechanical means, a powder or a slurry of a compound of the active ion or other dopant. A melt is formed at the end of the rod with a laser beam and a reduced diameter doped single-crystal fiber is grown or drawn from the melt by pulling with a wire or, when desired crystalline orientation is needed, by pulling with a pointed and oriented seed crystal. The pulling step, at least in the specific case of a neodymium-doped yttrium aluminum garnet (YAG) fiber, is repeated a plurality of times with approximately a 3:1 diameter reduction each time in order to obtain the desired fiber size; but only one deposition of the dopant compound is needed.

Abstract: An apparatus for controlling a radial path of resistance in a semiconductor monocrystalline rod produced by a crucible-free zone melting whereby the material flow path and heat distribution in the melt zone is controlled by a guided stream of protective gas.

Abstract: A crystal growing furnace is provided wherein the molten material in the crucible is replaced constantly as it is withdrawn by a monitoring system which automatically maintains the level in the crucible at a desired point. A replaceable cannister system is also provided so that the level can be maintained indefinitely by replacing the cannisters.

Abstract: In a catalytic method for selectively detecting carbon monoxide in the presence of hydrogen in an oxygen-containing atmosphere, such as may be used in monitoring exhaust gases from combustion processes, the catalyst is a platinum-rhodium alloy containing not less than about 10% rhodium. The catalyst is maintained at a temperature such that it will cause combustion of carbon monoxide but will not readily cause combustion of hydrogen, the thermal effect on the catalyst resulting when a test atmosphere is brought into contact with it being sensed to provide a measure of the carbon monoxide concentration in that atmosphere.

Abstract: A method and test of detecting occult blood in a stool or other physiologic fluid sample which offers novelty in that the reaction is carried out in the organic phase selected from the group consisting of methylene dichloride, petroleum ether, and dioxane in an aqueous/organic bi-phase system wherein the sample of occult blood is added to the aqueous phase, the bi-phase system is mixed by emulsification and a standard color-forming reaction involving organically soluble hemoglobin (heme), peroxide, and dye is carried out in the organic phase. Optionally, a filter paper porous only to organic solvents may be introduced to initially separate the aqueous and organic phases and further a device for mixing and separating immiscible liquids having two chambers telescopable into one another may be utilized. The reaction involving hemoglobin is carried out in acetic acid to produce heme which is later solubilized by the organic solvent.

Abstract: An apparatus for preparing a semiconductor compound, having one compound with a substantially higher vapor pressure than the other using a closed horizontal tube disposed in a pressure vessel. The two ends of the tube are located in respective heating ovens having their ends facing away from the tube closed. The heating ovens and tube are disposed within a pressure vessel with the heating ovens having an outside diameter which is considerably smaller than the inside diameter of the pressure vessel and with the total length of the heating ovens arranged one behind the other in the axial direction of the tube substantially smaller than the length of the pressure vessel. In addition, a portion of the tube located between the ovens has associated therewith a separate cooling device.

Abstract: The evaporation of volatile non-aqueous liquids is inhibited by a floating layer of expanded cereal grains optionally treated with fluorocarbons or perlite treated with fluorocarbons.

Abstract: Grignard reagent is produced continuously in a reactor vessel, overflowing into a holding vessel from which the product is continuously removed; the reaction proceeds in the presence of an excess of magnesium constantly maintained, and a portion of the reacting mixture is withdrawn, circulated to a heat exchanger and returned to the reactor vessel.

Abstract: Automatic control of the growth from the melt of a crystal in the Czochralski technique by weighing the crystal, comparing the weight with its expected value in a comparator and using the difference in a servo-loop as a servo-control signal is known. The servo-control signal modulates the melt heater power which adjusts the temperature isotherms of the melt in order to maintain the crystal cross-sectional area constant. It has been found that a thermal delay which occurs when heat is conducted from the melt crucible to the crystal/melt interface can cause the crystal cross-sectional area to depart from its uniform expected value. The effect of the thermal delay is compensated for by a phase advance circuit which is connected to the output of the servo-loop comparator.

Abstract: A method for preparing single crystals of lanthanum hexaboride (LaB.sub.6) by arc melting a rod of compacted LaB.sub.6 powder. The method is especially suitable for preparing single crystal LaB.sub.6 cathodes for use in scanning electron microscopes (SEM) and scanning transmission electron microscopes (STEM).

Abstract: Device for making monocrystalline gallium arsenide by drawing the crystal from a gallium arsenide-containing melt with adjustment of an arsenic vapor pressure while rotating and lifting the drawing means, said device comprising means for rotating the crucible containing an uncovered melt, and if desired, lifting or lowering the crucible independently of the system, that is to say without rotating the entire quartz apparatus. The means for rotating the crucible includes a ground-in joint formed by the core of the crucible driving shaft and a quartz glass sleeve. The core is made of a material havinga higher coefficient of expansion than quartz glass at the operating temperature of the joint. The accurate seating of the ground-in joint avoids the formation of surface waves on the melt.

Abstract: The invention is an improvement in apparatus for growing crystalline bodies from the melt. The apparatus comprises a crucible and a novel die assembly in which the die assembly is made in two parts and essentially comprises inner and outer concentric members. The inner and outer members are spaced from one another to define an annular lower capillary section. One member is longer than the other and is shaped so that its upper end overhangs and engages the upper end of the other member. A plurality of upstanding dies are formed in the upper end of the longer member. Each of the dies has a top end surface and is slotted in a generally radial direction with the slots being deep enough to intersect the annular space between the two members. The slots in the dies serve as capillaries to provide communication between the lower capillary section and the top end surfaces of the dies.

Abstract: In a process for determining the total mercury content in samples of effluent water, the sample is collected on a sample collector where it is evaporated at 1000.degree. C before it is decomposed in a pyrolysis zone at 1000.degree. to 1200.degree. C. The mercury in the liquid sample is thereby expelled as vapor and together with carrier gas it is conducted over a metal sheet which absorbs the mercury and concentrates it. The concentrated mercury is then expelled by heating the metal and transferred by the carrier gas into a mercury absorption photometer where it is determined quantitatively.

Abstract: The concentration of gas is determined by monitoring the coloration of a reagent test paper, or the like, whose color changes progressively or otherwise in response to continued exposure to such gas. The concentration is determined by determining the length of time which the reagent test paper must be exposed to the gas for the coloration of the test paper to reach a preselected threshold value.

Abstract: In apparatus for the preparation of a semiconductor compound such as gallium phosphide using the Bridgman method in a horizontal system equipped with a heating device and disposed in a pressure vessel, the reaction tube is mounted in a stationary fashion in a reaction boat and the heating device supported so that it is moveable in the direction of the horizontal axis of the system to permit synthesis of the semiconductor compound along with zone melting and drawing of single crystals. A light guide having its free end arranged below the reaction tube is mounted to the heating device for movement therewith and is used to measure the temperature at the reaction boat.