摘要:
Process for the preparation of 2,3-dihydro-2,2-dimethyl-7-benzofuranol, comprising the reaction between catechol or 4-tert.butyl catechol and isobutyraldehyde in the presence of catalytic amounts of at least one compound selected from the group consisting of the oxides, hydroxides, alcoholates and carboxylates of metals belonging to the Groups IA, IIA, IIB and VIIB of the Periodic System of the Elements and the subsequent reaction of rearrangement of the products which have been obtained, optionally previously removing one or more low-boiling components, in the presence of a compound having acidic properties, of an organic or a mineral nature. The product is useful in the synthesis of pesticides.
摘要:
A process is provided for preparing a substituted 2,3-dihydrobenzofuran of the general formula ##STR1## in which R.sub.a is hydrogen, halogen, alkyl, straight or branched having from 1 to 4 carbon atoms, aryl, alkaryl, --OH, --OR.sub.3, --N(R.sub.d).sub.2, where R.sub.3 and R.sub.d are alkyl, straight or branched having from 1 to 4 carbon atoms; R.sub.b is alkyl, straight or branched, having from 1 to 6 carbon atoms, aryl, alkaryl; and R.sub.c is hydrogen or the same as R.sub.b, by the rearrangement of a 1,1-bis(2-hydroxybenzene) alkyl and/or aryl-ethane, in the presence of catalytic amounts of a mineral acid or organic acid such as phosphoric, sulfuric or p-toluenesulfonic, at elevated temperatures from 180.degree. to 250.degree. C., and withdrawing the resulting products from the reaction mixture as they are formed. The starting 1,1-bis(2-hydroxybenzene) alkyl and/or aryl-ethane compounds may be obtained by the catalyzed reaction of a substituted biphenol with an aldehyde. The substituted 2,3-dihydrobenzofurans are useful in the manufacture of pesticides.
摘要:
A new group of pentaerythryl diphosphonates and poly(pentaerythryl diphosphonates) are described. Flame-retardant compositions are also described, which include a thermoplastic polymer and a certain amount of self-extinguishing agent consisting of one of the above-mentioned pentaerythryl diphosphonates or poly(pentaerythryl diphosphonates).
摘要:
A new group of pentaerythryl diphosphonates and poly(pentaerythryl diphosphonates) are described. Flame-retardant compositions are also described, which include a thermoplastic polymer and a certain amount of self-extinguishing agent consisting of one of the above-mentioned pentaerythryl diphosphonates or poly(pentaerythryl diphosphonates).
摘要:
A photochromatic compound represented by the following general formula (I): ##STR1## where: R.sub.1 and R.sub.2 independently represent a linear, branched or cyclic C1-C10 alkyl radical, H, OH, F, Cl, Br, NH.sub.2, N(R.sub.4).sub.2, COOH, OR.sub.4 or COOR.sub.4 where R.sub.4 is a C1-C10 linear, branched or cyclic alkyl radical, or an aryl radical;R.sub.3 is a variously substituted mono or polycondensed heterocyclic or aryl radical.A compound (I) demonstrates marked photochromatic characteristics both when in an organic solvent solution and when incorporated into polymer matrices.
摘要:
Methods and apparatus are described for measuring noise in video image processing. The described methods use horizontal and vertical variances of pixels of an image to extract noise information from the image. Silent regions in an image are considered to determine amplitude variations in the image. A smallest silent region in the image is searched by performing measurements over various block sizes. A least sum of absolute differences approach is used on both horizontal and vertical directions for finding the minimum energy of a received image signal. Using the disclosed method and processor, with a Gaussian distribution for the measured channel noise, both silent image regions, as well as edges, are equally covered.
摘要:
Method of providing closed captioned data to a television viewer comprised of detecting closed captioned data signals transmitted in conjunction with a television signal, decoding the data signals to caption display signals, and displaying the caption display signals on an auxiliary screen separate from a screen displaying the television signals.
摘要:
Method of providing closed captioned data to a television viewer comprised of detecting closed captioned data signals transmitted in conjunction with a television signal, decoding the data signals to caption display signals, and displaying the caption display signals on an auxiliary screen separate from a screen displaying the television signals.
摘要:
A method and apparatus are disclosed wherein the horizontal and vertical variances of the pixels of an image are determined to calculate a noise measurement in a received image.
摘要:
A method and apparatus for detecting copy protection included in an input video signal is described. Two types of copy protection are particularly addressed, including techniques that imbed copy protection pulses and copy protection phase flips in the video signal. A method for preserving copy protection is also presented, where the input video signal is first examined to determine if copy protection has been included in the input video signal. The input video signal then converted to component video data, which removes any copy protection present. An output video signal is then generated from the component video data, and when it was determined that the input video signal includes copy protection, the copy protection is recreated in the output video signal.