摘要:
A method for preparing semiconductor nanocrystals comprises reacting cation precursors and anion precursors in a reaction mixture including one or more acids, one or more phenol compounds, and a solvent to produce semiconductor nanocrystals having a predetermined composition. A method for forming a coating on at least a portion of a population of semiconductor nanocrystals is also disclosed. The method comprises forming a first mixture including a population of semiconductor nanocrystals, one or more amine compounds, and a first solvent; adding cation precursors and anion precursors to the first mixture at a temperature sufficient for growing a semiconductor material on at least a portion of an outer surface of at least a portion of the population of semiconductor nanocrystals; and initiating addition of one or more acids to the first mixture after addition of the cation and anion precursors is initiated. Semiconductor nanocrystals and populations thereof are also disclosed.
摘要:
A method for preparing semiconductor nanocrystals comprises reacting cation precursors and anion precursors in a reaction mixture including one or more acids, one or more phenol compounds, and a solvent to produce semiconductor nanocrystals having a predetermined composition. A method for forming a coating on at least a portion of a population of semiconductor nanocrystals is also disclosed. The method comprises forming a first mixture including a population of semiconductor nanocrystals, one or more amine compounds, and a first solvent; adding cation precursors and anion precursors to the first mixture at a temperature sufficient for growing a semiconductor material on at least a portion of an outer surface of at least a portion of the population of semiconductor nanocrystals; and initiating addition of one or more acids to the first mixture after addition of the cation and anion precursors is initiated. Semiconductor nanocrystals and populations thereof are also disclosed.
摘要:
A method for preparing semiconductor nanocrystals is disclosed. The method includes adding one or more cation precursors and one or more anion precursors in a reaction mixture including a solvent in a reaction vessel, maintaining the reaction mixture at a first temperature and for a first time period sufficient to produce semiconductor nanocrystal seed particles of the cation and the anion, and maintaining the reaction mixture at a second temperature that is higher than the first temperature for a second time period sufficient to enlarge the semiconductor nanocrystal seed particles to produce semiconductor nanocrystals from the cation and the anion.
摘要:
A non-volatile memory cell having a split gate, wherein the floating gate and the coupling/control gate have complimentary non-planar shapes. The shape may be a step shape. An array of such cells and a method of manufacturing the cells are also disclosed.
摘要:
A non-volatile memory cell has a single crystalline substrate of a first conductivity type with a top surface. A first region of a second conductivity type is in the substrate along the top surface. A second region of the second conductivity type is in the substrate along the top surface, spaced apart from the first region. A channel region is the first region and the second region. A word line gate is positioned over a first portion of the channel region, immediately adjacent to the first region. The word line gate is spaced apart from the channel region by a first insulating layer. A floating gate is positioned over another portion of the channel region. The floating gate has a lower surface separated from the channel region by a second insulating layer, and an upper surface opposite the lower surface. The floating gate has a first side wall adjacent to but separated from the word line gate; and a second side wall opposite the first side wall. The second side wall and the upper surface form a sharp edge, with the second side wall greater in length than the first side wall. The upper surface slopes upward from the first side wall to the second side wall. A coupling gate is positioned over the upper surface of the floating gate and is insulated therefrom by a third insulating layer. An erase gate is positioned adjacent to the second side wall of the floating gate. The erase gate is positioned over the second region and insulated therefrom.
摘要:
Bimetallic catalyst for producing polyethylene resins with a bimodal molecular weight distribution, its preparation and use. The catalyst is obtainable by a process which includes contacting a support material with an organomagnesium component and carbonyl-containing component. The support material so treated is contacted with a non-metallocene transition metal component to obtain a catalyst intermediate, the latter being contacted with an aluminoxane component and a metallocene component. This catalyst may be further activated with, e.g., alkylaluminum cocatalyst, and contacted, under polymerization conditions, with ethylene and optionally one or more comonomers, to produce ethylene homo- or copolymers with a bimodal molecular weight distribution and improved resin swell properties in a single reactor. These ethylene polymers are particularly suitable for blow molding applications.
摘要:
The present invention is directed to processes of polymerization of olefins and copolymerization of olefins and functionalized olefins in the presence of certain late transition metal bidentate salicylaldimine chelates represented by the formula: wherein each of the symbols R, R1, R2, R3, R4, R5, R6, L, M, A, X and z are defined within the specification herein below.
摘要:
Substantially linear vinylene carbonate/1-olefin copolymers, a process of forming the same, and packaging materials incorporating the same are described. These copolymers are formed by reacting the component monomers in the presence of a single component, non-ionic polymerization catalyst at relatively low temperatures and pressures.
摘要:
A catalyst composition for the polymerization of olefins is provided which comprises a catalyst compound and a co-catalyst or a support material or both a co-catalyst and a support material, wherein the catalyst compound comprises a transition metal of Group 4, 5 or 6, an organic compound containing at least one lone pair of electrons, a divalent radical and a Lewis basic group having the following formula: —C(R7)=Z1R8, (i) wherein R7 and R8 are each independently selected from the group consisting of hydrogen and C1-C8 hydrocarbyl groups, and wherein R7 and R8 are not linked or are linked to form a saturated or unsaturated ring; and Z1 is a nitrogen atom or a phosphorus atom, which bonds to M; or wherein: Z2 is an oxygen atom, a sulphur atom or a selenium atom, which bonds to the transition metal compound; and R9, R10 and R11 are each independently selected from the group consisting of hydrogen and C1-C8 hydrocarbyl groups, wherein no pair or one pair of substituents selected from R9, R10 and R11 are linked to form a saturated or unsaturated ring.
摘要:
Disclosed is an optical disk, card or media which comprises: a) a plurality of data structures that are readable by the interrogating beam of light; and b)a composition on or in the optical disk, card or media disposed so that when the optical disk, card or media is used in the optical read-out system, the interrogating beam of light passes through the composition before or after contacting some or all of the data structures. The composition comprises a polymeric matrix with an organometallic complex dissolved therein or with metal, transition metal, metal oxide or transition metal oxide nanoparticles uniformly dispersed therein. The composition is substantially transparent to the interrogating beam and/or is substantially colorless. Alternatively, the composition comprises a solid polymeric matrix with an olefinic compound dissolved or uniformly dispersed therein wherein double bond in the olefinic compound undergoes oxidative cleavage promoted by a transition metal catalyst and a thiophenol or a catalytic amount of a thiyl radical and wherein the composition is substantially transparent to the interrogating beam and/or is substantially colorless.