Abstract: A microlens array includes short lengths of fibre held across an aperture in a rigid body. The fibres are conveniently short lengths cut from commercially available ultraviolet grade fused silica fibre that has had a normal outer protective coating removed. The microlens array is comparatively cheap to make and has particular application in producing long period gratings by exposing strands of silica fibre to UV radiation via the microlens array using a diffraction pattern produced by the microlens.
Abstract: A versatile modelling for any standard power system component is disclosed, by which the component modules can be easily plugged into the network module to form a small perturbation state space model of the entire system irrespective of the complexity of the system. The state equation is available as explicitly a function of every parameter and the input and output can be any variable, thus providing insight into the physical nature by simple matrix manipulation.
Abstract: A bonding tool for applying pressure and ultrasonic energy simultaneously to join miniature components together includes an ultrasonic driver having four composite wafers separated by electrodes. Such bonding tools are known that use wafers made of wholly of ceramic material. By using wafers having four sector parts of ceramic material separated by layers of polymer as shown, bonding tools are provided with broader bandwidth operation and reduced spurious resonance modes.
Type:
Grant
Filed:
April 23, 1999
Date of Patent:
February 20, 2001
Assignee:
The Hong Kong Polytechnic University
Inventors:
Helen Lai Wa Chan, Siu Wing Or, Kei Chun Cheng, Chung Loong Choy
Abstract: A method for measuring the antioxidant capacity and/or the amount of a specific antioxidant in a sample, which comprises:
a) at least two samples (A) and (B) to be assayed in parallel;
b) addition of an antioxidant deactivator to sample (A) which selectively deactivates the antioxidant ability of an antioxidant in the sample;
c) addition of a redox indicator to both samples (A) and (B), the indicator being capable of indicating the antioxidant capacity of each sample absorbance of electromagnetic radiation;
d) measurement of the change in absorbance of electromagnetic radiation of the indicator in each sample at a given time interval, from the time when the redox indicator was added to or mixed with the samples or immediately prior to this addition or mixing until a given time after the redox indicator was added;
e) determining the antioxidant capacity of the sample and/or the specific antioxidant in the sample, by relating the change in absorbance of electromagnetic radiation of step (d) to the absorban
Abstract: Novel soluble polyester-supported chiral phosphines have been prepared and have been used in the preparation of rhodium and ruthenium catalysts. Such polymer-supported catalysts show high catalytic activities and enantioselectivities. In the case of Ru(BINAP) catalyst supported on soluble polyester, the resulting catalysts were found to be more active than those of the corresponding homogeneous Ru(BINAP) catalysts in the asymmetric hydrogenation of 2-arylpropenoic acids. These soluble polyester-supported catalysts can be easily separated from the reaction mixture and then be reused without loss of activity and selectivity.
Abstract: This invention relates to (R)- and (S)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl-2,2'-diamine (R-1 and S-1) and (R)- and (S)-2,2'-bis(diarylphospinoamino)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binap hthyl (R-2 and S-2) and (R)- and (S)-2,2'-bis(diaklphospinoamino)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaph thyl (R-3 and S-3); to a process for the preparation of R-1 and S-1 in which (R) or (S)-1,1'-binaphthyl-2,2'-diamine is partially hydrogenated in the presence of Adam's catalyst (5-20 wt/o of starting material) at 20-100.degree. C.
Abstract: This invention relates to (R)- and (S)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binaphthyl-2,2'-diamine (R-1 and S-1) and (R)- and (S)-2,2'-bis(diarylphospinoamino)-5,5',6,6',7,7',8,8'-octahydro-1,1'-binap hthyl (R-2 and S-2) and (R)- and (S)-2,2'-bis(dialkylphospinoamino)-5,5',6,6',7,7',8,8'-octahydro-1,1'-bina phthyl (R-3 and S-3); to a process for the preparation of R-1 and S-1 in which (R) or (S)-1,1'-binaphthyl-2,2'-diamine is partially hydrogenated in the presence of Adam's catalyst (5-20 wt % of starting material) at 20-100.degree. C.
Abstract: Novel, optically active phosphorous compounds of the formula, ##STR1## wherein R.sup.1 represents hydrogen atoms, straight or branched-chain alkyl groups having from 1 to 6 carbon atoms, R.sup.2 represents hydrogen atoms, halogen atoms, lower alkyl groups (1 to 6 carbon atoms), lower alkoxy groups (1 to 6 carbon atoms), hydroxy group, chiral hydroxyalkyl groups, and amino groups (1.degree., 2.degree., 3.degree.) vinyl groups or allyl groups and R.sup.3 represents phenyl groups, aryl groups, cyclohexyl groups, substituted and unsubstituted cycloalkyl groups, heteroaromatic rings, are described. The compounds of the formula serve as highly useful ligands in the preparation of ruthenium complexes which are effective catalysts for the asymmetric hydrogenation of 2-arylpropenoic acids leading to high valued 2-arylpropionic acids.
Abstract: New optically active phosphinite compounds which are useful in asymmetric catalysis have been synthesized and have been used in the preparation of rhodium catalysts. Such catalysts are particularly useful in enantioselective catalytic hydrogenation reactions.
Type:
Grant
Filed:
February 24, 1997
Date of Patent:
May 26, 1998
Assignee:
The Hong Kong Polytechnic University
Inventors:
Albert Sun-Chi Chan, Yao-Zhong Jiang, Ai-Qiao Mi, Ming Yan, Wen-Hao Hu