Abstract:
A flexible and efficient bulk micromachining method for fabricating a novel microstructure that is bounded by substantially planar surfaces meeting only at substantially right angle corner features. The novel microstructure of the present invention is useful as a spacer in assembly processes where high accuracy is required, such as precise positioning of optical fibers or conductors. In the preferred embodiment, the microstructure of the present invention includes a shelf feature disposed along a height dimension of the microstructure, which is required for some applications. The bulk micromachining method of the present invention includes providing a first substrate having a top planar surface and an opposing planar surface. The opposing surface of the substrate is anisotropically etched to provide a first thinned region. The top surface of the first substrate is anisotropically etched so that a first recessed feature having a vertical side is made integral with the first thinned region. Similarly, a second substrate having a top planar surface and an opposing planar surface is provided. The opposing surface of the second substrate is anisotropically etched to provide a second thinned region. The top surface of the second substrate is anisotropically etched so that a second recessed feature having a vertical side wall is made integral with the second thinned region. The top surface of the first substrate is aligned and coupled with the top surface of the second substrate to produce the desired microstructure. The substrates are cut or sawn to free the microstructure.
Abstract:
An integration of a micromachined actuator and a signal transmission structure includes a thermal actuator on a side of a displaceable signal line opposite to a fixed signal line. The actuator includes first and second legs. The first leg has a cross-sectional area greater than the second leg, providing a differential in electrical resistance. As current is channeled through the legs, the second leg will elongate more and will deflect both of the legs. The deflection is in a direction to press the displaceable signal line into signal communication with the fixed signal line. Optionally, a thermally operated reset actuator can be positioned to provide a mechanical return of the displaceable signal line. In a preferred embodiment, a microwave transmission environment is provided.
Abstract:
A process is disclosed for removing residual sulfur from a hydrotreated naphtha feedstock. The feedstock is contacted with molecular hydrogen under reforming conditions in the presence of a less sulfur sensitive reforming catalyst to convert trace sulfur compounds to H.sub.2 S, and to form a first effluent. The first effluent is contacted with a solid sulfur sorbent to remove the H.sub.2 S and form a second effluent. The second effluent is then contacted with a highly selective reforming catalyst under severe reforming conditions. Also disclosed is a method using a potassium containing sulfur sorbent made from nitrogen-free potassium compounds.
Abstract:
A process for removing residual sulfur from a hydrotreated naphtha feedstock is disclosed. The feedstock is contacted with molecular hydrogen under reforming conditions in the presence of a less sulfur sensitive reforming catalyst, thereby converting trace sulfur compounds to H.sub.2 S, and forming a first effluent. The first effluent is contacted with a solid sulfur sorbent, removing the H.sub.2 S and forming a second effluent. The second effluent is contacted with a highly selective reforming catalyst under severe reforming conditions.
Abstract:
A process is disclosed for removing sulfur from a naphtha feedstream comprising contacting a naphtha feed with a platinum on alumina sulfur conversion catalyst under mild reforming conditions so that thiophenic and other organic sulfur compounds are converted to hydrogen sulfide without any significant cracking of the naphtha feed. Thereafter, the naphtha feed stream is contacted with a sulfur sorbent that has a metal component selected from Group I-A or Group II-A of the Periodic Table supported on a refractory inorganic oxide support, to remove hydrogen sulfide from the naphtha feed.
Abstract:
A pretreatment process is disclosed for increasing conversion of reforming catalysts wherein the catalyst is treated at from 120.degree. C. to 260.degree. C.; then the temperature of the treated catalyst is maintained at a temperature of from 370.degree. C. to 600.degree. C. in a reducing atmosphere prior to starting the hydrocarbon feed. Preferably, the catalyst is treated in the presence of hydrogen at atmospheric pressure for at least twenty minutes; then the temperature of the treated catalyst is maintained at 475.degree. C. in a reducing atmosphere for at least ten minutes prior to starting the hydrocarbon feed.
Abstract:
A hydrocarbon conversion process is disclosed wherein a hydrocarbon feed is contacted with a dehydrocyclization catalyst containing a large-pore zeolite and a Group VIII metal, then the resulting reformate is upgraded using an intermediate pore size zeolite.