摘要:
A flexural-mode, micromechanical resonator utilizing a non-intrusive support structure to achieve measured Q's as high as 8,400 at VHF frequencies from 30-90 MHz is manufactured using polysilicon surface micromachining technology. Also, a method for extending the operating frequency of the resonator as well as other types of micromechanical resonators is disclosed. One embodiment of the method is called a differential-signaling technique. The other embodiment of the method is called a dimple-down technique. The support structure includes one or more torsional-mode support springs in the form of beams that effectively isolate a resonator beam from its anchors via quarter-wavelength impedance transformations, minimizing anchor dissipation and allowing the resonator to achieve high Q with high stiffness in the VHF frequency range. The resonator also includes one or more spacers in the form of dimples formed on the flexural resonator beam or the substrate. In operation, the dimples determine a capacitive-transducer gap of the resonator. When a large DC-bias voltage is applied between a drive electrode and the resonator beam, the dimples provide a predetermined minimum distance between the flexural resonator beam and the drive electrode.
摘要:
A batch-compatible, post-fabrication annealing method and system are described that can be used to trim the resonance frequency and enhance the quality factor of mechanical microstructures, particularly micromechanical structures, such as micromechanical resonators. The technique involves running a current through a micromechanical structure, or through a nearby microstructure (e.g., a nearby resistor), thereby dissipating power and heating the structure to temperatures high enough to change its microstructure and/or its material properties, which then lead to changes in the microstructure's resonance frequency and quality factor. For micromechanical structures, this technique is particularly useful, since it allows for convenient, simultaneous trimming of many microstructures all at once, and can be implemented via the simple application of a voltage across the anchor points of a micromechanical structure.
摘要:
A batch-compatible, post-fabrication annealing method and system are described that can be used to trim the resonance frequency and enhance the quality factor of mechanical microstructures, particularly micromechanical structures, such as micromechanical resonators. The technique involves running a current through a micromechanical structure, or through a nearby microstructure (e.g., a nearby resistor), thereby dissipating power and heating the structure to temperatures high enough to change its microstructure and/or its material properties, which then lead to changes in the microstructure's resonance frequency and quality factor. For micromechanical structures, this technique is particularly useful, since it allows for convenient, simultaneous trimming of many microstructures all at once, and can be implemented via the simple application of a voltage across the anchor points of a micromechanical structure.
摘要:
A process for converting paraffins, especially light paraffins, e.g. C3-C8 paraffins, to higher boiling range paraffinic liquid hydrocarbons comprises endothermically dehydrogenating the light paraffin combined with a thermally coupled, exothermic reaction such as olefin oligomerization to supply heat for the endothermic conversion.
摘要:
In a process for producing phenol, a composition comprising an alkylaromatic compound is contacted with an oxygen-containing stream in the presence of an oxidation catalyst comprising a cyclic imide under oxidation conditions effective to oxidize 15 wt % or less of the alkylaromatic compound based upon the total weight of the composition and produce an oxidation product comprising unreacted alkylaromatic compound and alkylaromatic hydroperoxide in a molar ratio of 6:1 to 100:1. Thereafter, at least a portion of the oxidation product is contacted with an acidic molecular sieve catalyst under cleavage conditions effective to convert at least a portion of the alkylaromatic hydroperoxide into phenol and cyclohexanone.
摘要:
In a process for producing phenol, cyclohexylbenzene is contacted with an oxygen-containing compound in the presence of an oxidation catalyst comprising a cyclic imide under oxidation conditions effective to produce a product comprising cyclohexylbenzene hydroperoxide and unreacted cyclic imide catalyst. Without removing all the unreacted cyclic imide catalyst, at least a portion of the product is contacted with an acidic molecular sieve under conditions effective to adsorb at least a portion of the unreacted cyclic imide and to convert at least part of the cyclohexylbenzene hydroperoxide in the product portion into phenol and cyclohexanone.
摘要:
A paper medium identifying device and an identifying method. The paper medium identifying device comprises an image data obtaining unit, a faulty wire detecting unit, an image dividing unit, a standard template data storage unit, a comprehensive analyzing unit, a new template generating unit and a judging unit. The paper medium identifying device divides the standard template into new sub-templates by dividing the template from a faulty wire position as margin, and then matches the sub-templates with a papery medium image which being identified so as to avoid the influence of faulty wires on the template match identification and improve the acceptance rate of the papery medium identifying device.
摘要:
In a process for producing phenol, a feed comprising cyclohexylbenzene hydroperoxide is contacted with a cleavage catalyst comprising a fluorinated acidic resin under cleavage conditions effective to convert at least a portion of the cyclohexylbenzene hydroperoxide into phenol and cyclohexanone.
摘要:
In a process for producing phenol, a feed comprising cyclohexylbenzene hydroperoxide is contacted with a cleavage catalyst comprising an acidic ionic liquid under cleavage conditions effective to cleave at least a portion of said cyclohexylbenzene hydroperoxide and produce a cleavage product stream comprising phenol and cyclohexanone.
摘要:
Methods and systems are provided for analyzing parallelism of program code. According to a method, the sequential execution of the program code is simulated so as to trace the execution procedure of the program code, and parallelism of the program code is analyzed based on the result of the trace to the execution procedure of the program code. Execution information of the program code is collected by simulating the sequential execution of the program code, and parallelism of the program code is analyzed based on the collected execution information, so as to allow programmers to perform parallel task partitioning of the program code with respect to a multi-core architecture more effectively, thus increasing the efficiency of parallel software development.