Abstract: An artificial soil structure includes at least one hydrophobic layer of hydrophobic particles provided in a soil. A particle size of the hydrophobic particles can be 2000 micrometers and less. The hydrophobic particles are sand and/or dirt treated with a water-repellent agent or hydrophobic particles having a high molecular weight polymer. An artificial water-retentive soil structure includes a soil block containing a water-retentive agent and a hydrophobic layer of hydrophobic particles provided on the soil block. A method of preventing land desertification includes the steps of placing a hydrophobic layer of hydrophobic particles in a soil at a prescribed depth from the earth surface and controlling the water content in said soil.

Abstract: A control composition which comprises Z,Z/Z,E-7,11-hexadecadienyl acetate and Z,Z/Z,E-7,11-hexadecadienyl alcohol is released into a cotton field in a weight ratio of Z,Z/Z,E-7,11-hexadecadienyl acetate to Z,Z/Z,E-7,11-hexadecadienyl alcohol ranging from 99.2:0.8 to 90:10. The control composition is preferably released in the weight ratio defined above and in a rate ranging from 4 to 80 mg/hr/hectare of field.

Abstract: An improved method is proposed for the preparation of a sex pheromone dispenser used in the elimination of pest insects from the field by the disruption of mating of the insects by distributing sustained-release dispensers containing the sex pheromone compound of the insect over the field. According to the invention, pheromone dispensers made from a polyolefin-based resin and filled with the liquid pheromone are subjected, prior to distribution over the field at a relatively low temperature in early spring, to a pretreatment of keeping them at 35.degree. to 60.degree. C. until the dispenser walls of the polyolefin resin absorb 2 to 10% by weight of the pheromone. When the dispensers after the pre-treatment are distributed, a relatively high rate of pheromone release can be obtained at the low temperature as compared with untreated dispensers so that the rate of pheromone release can be relatively uniform over the whole period of the season in which the pheromone dispensers are kept over the field.

Abstract: An artificial soil structure includes at least one hydrophobic layer of hydrophobic particles provided in a soil. A particle size of the hydrophobic particles can be 2000 micrometers and less. The hydrophobic particles are sand and/or dirt treated with a water-repellent agent or hydrophobic particles having a high molecular weight polymer. An artificial water-retentive soil structure includes a soil block containing a water-retentive agent and a hydrophobic layer of hydrophobic particles provided on the soil block. A method of preventing land desertification includes the steps of placing a hydrophobic layer of hydrophobic particles in a soil at a prescribed depth from the earth surface and controlling the water content in said soil.

Abstract: An agent for the prevention of salt damage of plants for use in intermediate soil comprised of water-repellent particles, and a method of preventing salt damage to plants from salty soil using an agent to establish a water-repellent layer as a layer above the underground water level. An agent for the prevention of salt accumulation in greenhouse soil comprised of hydrophobic particles which are substantially hydrophobic. A salt accumulation prevention layer containing an agent for the prevention of salt accumulation in greenhouse soil which is provided at the surface layer or a prescribed depth from the surface layer of the greenhouse soil.

Abstract: A soil block for pot plant cultivation having a water-retentive layer, a hydrophobic layer above it, and a soil layer above that is provided. The water-retentive layer may consist of a sand layer, a water layer or a sand layer retaining water. The hydrophobic layer may consist of hydrophobic particles which are sand and/or dirt particles treated with a water-repellent agent, a water-repellent membrane including nonwoven fabric, woven fabric or knitted fabric treated with a water-repellent agent, or such. According to the method of cultivating pot plants, the pot plants are planted in the soil layer, which is the upper layer in the soil block for pot plant cultivation, and water is supplied to maintain the water content in the water-retentive layer at a constant level.

Abstract: A method of manufacturing an Nb.sub.3 Sn superconducting wire includes the steps of composing a desired number of rods, constituted by a material selected from the group consisting of Nb and an Nb alloy, in a Cu-Sn-based alloy matrix containing 15.1 to 24.6 wt % of Sn, thus forming a composite billet, subjecting the composite billet to hot working, subjecting the composite billet to cold or warm working to reduce a diameter and annealing repeatedly to divide an intermetallic compound phase in the Cu-Sn-based alloy into small pieces, thus obtaining a composite wire, and subjecting the composite wire to predetermined heating to diffuse Sn in Nb. A method of manufacturing an Nb.sub.

Abstract: In the technology of population control of lepidopteral insects as an agricultural or horticultural pest, such as tomato pinworms, by distributing dispensers of sex pheromone of the species over the field, an unexpected discovery has been made that, to the contrary to the general understanding for the effectiveness of the E-isomer of the pheromone compound, e.g., 4-tridecenyl acetate, a rather higher activity can be obtained by using a mixture of the E-isomer and Z-isomer in a mixing proportion of 1:1 to 3:1 than the E-isomer in a high purity.

Abstract: The invention provides a dispenser form for substainedly releasing vapor of a sex pheromone compound of pest insects with an object to control the population of the insects. The invention dispenser is characterized by the features that: the capacity thereof is sufficiently large to contain at least 100 mg of the pheromone; the barrier wall thereof through which the pheromone permeates to be released from the outer surface is made of a polymeric material swellable with the pheromone in an equilibrium swelling of 2-6% by weight at 20.degree. C.; and the outer surface area S thereof given in mm.sup.2 is sufficient to give a ratio S/W, W being the amount of the pheromone contained therein given in mg, in the range from 4 to 11. The rate of pheromone emission from the dispenser is relatively constant at 0.6 mg/day or larger over a long period of time of, for example, 3 months or longer.

Abstract: An efficient cost- and labor-saving method is proposed for controlling the population of two kinds or more of different species of insectan pests in a field by means of distributing dispensers of sex pheromone compounds for the respective species of the insects when one of the sex pheromone compounds is an unsaturated C.sub.10 to C.sub.12 alcohol and the other is an unsaturated C.sub.14 to C.sub.20 acetate or aldehyde. When these two classes of the compounds are mixed in such a proportion that the overall solubility paramater .delta. of the mixture is 9.1 to 9.7 and the mixture is contained in a dispenser body made of polyethylene or a copolymer mainly composed of ethylene moiety, the two compounds can be concurrently emitted from the dispenser in the form of vapor each at a controlled rate over a desired length of time.

Abstract: Vinyl chloride polymers or copolymers having a relatively low molecular weight or degree of polymerization are prepared by a method in which an organic compound containing a mercapto group and a hydroxy or carboxyl group in a molecule is used as the chain transfer agent. Due to their very high activity, these chain transfer agents are used in amounts that are smaller than conventionally required quantities. The quality of the polymer products is satisfactory with respect to heat stability, occurrence of fish-eyes, particle size distribution, plasticizer absorption and ease of removing residual monomer.

Abstract: Vinyl chloride monomers or a monomeric mixture composed mainly of vinyl chloride is bulk-polymerized in a polymerization vessel. The inner walls and other surfaces of said vessel, coming into contact with the monomer or monomers, are coated with one or more specifically selected inorganic or organic compounds having a solubility greater than 0.5 g in 100 g of water at 25.degree. C and a boiling point higher than 60.degree. C. This bulk polymerization method serves to greatly reduce the deposition of polymer scale on the vessel walls and other surfaces. In addition the polymer scale deposited can be readily separated and removed by merely washing with water or gas under pressure. The present method provides high quality polymers.

Abstract: Unreacted monomer or monomers and any other volatile organic compounds contained in an aqueous dispersion of polymerizate are removed or separated by a method comprising circulating the aqueous polymerizate dispersion from the bottom of its container to the upper part of the container located over the surface of the dispersion via an exterior conduit. The pressure in the container is maintained at a level reduced to about the saturated vapor pressure of water at the temperature of the dispersion. This manner of separation of monomer from polymer serves to improve the working environment as well as the resulting polymer quality, and the monomer or monomers thus recoverd can be advantageously recycled.

Abstract: Vinyl chloride monomer, or a mixture thereof with a copolymerizable monomer or monomers, is bulkpolymerized so that the deposition of polymer scale on the inner walls of the polymerization vessel and other surfaces in contact with the monomer or monomers can be greatly reduced by coating them with phosphoric esters, polyphosphoric esters or their alkali metal salts before the polymerization is commenced. Clean-up operations following each polymerization run are much simplified.