摘要:
A process of manufacturing of a chromatography material comprising the steps of (i) reacting a polymerizable at least bifunctional monomer A with a ligand also having a functional group which binds covalently with one of the functional groups of said polymerizable bifunctional monomer A, (ii) to form a compound B comprising at least one polymerizable functional moiety (iii) polymerizing the compound B essentially alone or with the polymerizable monomers in presence of porogenes to obtain a block of porous polymerizate which is self-supporting or (iv) reacting the ligand and a spacer via a covalent bond which is cleavable to form a ligand-spacer conjugate and binding the ligand-spacer conjugate to the surface of a chromatographic support or reacting the ligand-spacer conjugate via a covalent bond to the at least bi-functional monomer A and polymerizing it essentially alone or with the polymerizable monomers in presence of porogenes to obtain a block of porous polymerizate which is self-supporting.
摘要:
A device for generating high-frequency mechanical vibrations for dental purposes comprises a current detector (50) fitted in the supply line of a vibration generator (12). The output signal of the current detector (50) is transmitted to one of the inputs of a control circuit (74), which at its other input receives a supply current nominal value signal. The output of the control circuit (74) is connected to the control terminal of a controllable oscillator (42), which together with a power stage (46 to 48) prepares the supply current for the vibration generator (12). In this manner, a constant output amplitude of the vibration generator is obtained independent of the load coupled to said vibration generator at any given time.
摘要:
A dental instrument for sonic or ultrasonic treatment comprises a shank (1) to which a treatment section (2) is joined. The shank (1) and treatment section.(2) are made of matrix-bonded carbon fibers. The instrument can be machined out of a woven carbon fiber fabric or can be a compression molding or an injection molding. The mechanical properties of the instrument can be adjusted by varying the length of the carbon fibers.
摘要:
A process for the preparation of 3,5,5-trimethylcyclohexa-3-en-1-one (&bgr;-isophorone) by isomerization of 3,5,5-trimethylcyclohexa-2-en-1-one (&agr;-isophorone) in the liquid phase in the presence of a salt-like or organometallic catalyst. By using catalytic quantities of alkali-metal salts or alkaline-earth salts and/or their organometallic compounds, and without addition of a further auxiliary substance, the space-time yield in the preparation of &bgr;-isophorone is high. &bgr;-Isophorone is particularly suitable as an intermediate product for the preparation of ketoisophorone.
摘要:
For ultrasonic preparation of hard or soft tissues or of tissue replacement material a apparatus is proposed comprising a hand piece (10), which includes an ultrasonic vibration generator (16), an ultrasonics deflecting head (28) as well as a tool (36) carried by the output member of the deflecting head. An abrasive treatment medium (48) is supplied to the working region defined between the tool (36) and the material (66) to be prepared. Thus even in places, which are difficult to access, cavities can be produced in dental or bone tissue in a gentle and precise manner.
摘要:
A method of producing 3,5,5-trimethylcyclohexa-3-ene-1-one (.beta.-isophorone) by isomerization of 3,5,5-trimethylcyclohexa-2-ene-1-one (.alpha.-isophorone) in a liquid phase in the presence of a homogeneous or heterogeneous catalyst in which a mixture with a relatively low concentration of .beta.-isophorone is drawn off from the reaction container and the .beta.-isophorone isolated by vacuum distillation. .beta.-isophorone is an important synthetic structural element for the production of carotinoids, vitamins and pharmaceutical products.
摘要:
An apparatus is provided for the selection of a tooth color for a dental prostheses in which an exact adaptation of the colors or color distribution of a dental prosthesis to a particular structural condition in a patient can be achieved. The apparatus, a platelet color specimen, has at least one lateral edge concavely curved towards a center region of the platelet. The platelet color specimen is on the order of magnitude of only a width of a tooth, and can be placed contiguous with the surface and edge of all exposed portions of a tooth. The platelet color specimen also exhibits only a single color corresponding to enamel, dentin or dental neck which allows for an exact adaptation to a particular patient.
摘要:
A chemical oxygen generator includes a candle in which oxygen is present and which is chemically combined and which is ignited by starting means to initiate the generation of the oxygen. This takes several seconds before a substantial quantity of oxygen is provided. Because a user of this oxygen must be supplied with the oxygen for respiration immediately, the invention includes a generator which has a pressure space, preferably above, below and around the oxygen candle which is located in the space and which is filled with compressed oxygen. The generator includes a member which is actuated upon release of the starting means for the oxygen to permit outward flow of the oxygen in the pressure space which is supplied until the oxygen being released from the candle is produced by the ignition of the candle.