Photochemical Copolymerization of Styrene with Methyl Methacrylate

The photochemical copolymerization of styrene with methyl methacrylate were investigated under various conditions. The reactivity ratio and the ? values were evaluated.     

Identifying entanglement using quantum ghost interference and imaging

We report a quantum interference and imaging experiment which allows identifying the entanglement in momentum and position variables of a two-photon system. The measurements show indeed that the uncertainties in the sum of momenta and in the difference of positions of the entangled two-photon satisfy both EPR inequalities Delta(k(1)+k(2))相似文献   

The physics of 2≠1+1

One of the most surprising consequences of quantum mechanics is the entanglement of two or more distant particles. In an entangled EPR two-particle system, the value of the momentum (position) for neither single subsystem is determined. However, if one of the subsystems is measured to have a certain momentum (position), the other subsystem is determined to have a unique corresponding value, despite the distance between them. This peculiar behavior of an entangled quantum system has surprisingly been observed experimentally in two-photon temporal and spatial correlation measurements, such as “ghost” interference and “ghost” imaging. This article addresses the fundamental concerns behind these experimental observations and to explore the nonclassical nature of two-photon superposition by emphasizing the physics of 2 ≠ 1 + 1.      

p to n conversion in SWIR mercury cadmium telluride with ion milling

Exposure to specific damage introduced by either ion implantation or ion milling converts p-type short wavelength infrared (SWIR) HgCdTe to n-type in a manner similar to the conversions in medium wavelength infrared (MWIR) or long wavelength infrared (LWIR) mercury cadmium telluride. However, the depth of conversion for SWIR Hg_1−xCd_xTe, with x=0.48, is approximately 300% smaller when compared to the depth of conversion for MWIR HgCdTe for an identical degree of ion milling. The depth of conversion, or the n/p junction depth, tracks linearly the extent of surface removals by ion milling when the metal vacancy concentration is held invariant. These results can be correlated to the interaction between metal vacancies and a product of the lattice damage process resulting from ion milling. The observation of a linear dependence of this depth on the degree or time of ion milling rules out the existence of a diffusive barrier in the transfer of this product for both MWIR and SWIR HgCdTe.     

Experimental method and FE simulation model for evaluation of wafer probing parameters

Wafer probing technology is a critical testing technology that is used in the semiconductor manufacturing and packaging process. A well-designed probing system must enable low and stable contact resistance when each needle-like probe makes contact with the IC chip-bonding pad. Mechanical contact using excessive probe force causes over-sized scrub marks that may damage the die pad and sizably deform the probe tip. In this paper, an experimental setup of a single tungsten needle probe making contact with an Al pad was employed to investigate the relationships between the overdrive, contact force, and scrub mark length. A three-dimensional computational probing simulation model was developed for analyzing dynamic deformations of the contact phenomena during wafer testing. The mechanical tensile strength of the tungsten needle was tested with a micro-tester to examine the tensile stress-strain relationship. The elastoplastic behaviors of the probe and die were taken into account in the simulation model. The resultant scrub lengths from the simulation were verified against the experimental data. Additional critical data, such as data of the scrub mark sinking on the die surface and the maximum Von-Mises stress level location at the probe tips, can be predicted. The experimental and numerical methods presented here can be used as useful performance evaluation tools to support the choice of suitable probe geometry and wafer probe testing parameters.     

Multi‐stage two‐leg bandwidth reservation and admission control for advance reservations with uncertain service duration

In traditional advance reservation (AR) service, resources were reserved for fixed scheduled periods at the time requests were admitted. When overtimes occurred, because of the reservation timeout, connections would be forced to terminate. For Internet AR applications like sports event casting and conference meetings such service disruption would be unfortunate and undesired for the viewers and participants. Further, taking into account that overtimes are often known almost at the last minute of the pre‐scheduled period, even if a connection extension request is submitted the probability that it is successful is unpredictable depending on the network load. In this paper, we study the problem of admission control and resource management for the AR service with uncertain service duration. An innovative multi‐stage two‐leg admission control and bandwidth management scheme is proposed. New performance measures—service quality indexes and reservation cost function are also defined for AR service. Through simulations, we show that the proposed scheme successfully provides service users a more predictive, affirmative service guarantee than conventional reservation schemes. Copyright © 2006 John Wiley & Sons, Ltd.     

Bidirectional Hybrid DWDM‐PON for HDTV/Gigabit Ethernet/CATV Applications

A new scheme for bi‐directional HDTV/Gigabit Ethernet/CATV transmission over a hybrid dense‐wavelength‐division‐multiplexing passive optical network (DWDM‐PON) is proposed and demonstrated. It is based on injection‐locked vertical‐cavity surface‐emitting lasers and distributed‐feedback laser diodes as transmitters. Services with 129 HDTV channels, a 1.25 Gbps Gigabit Ethernet connection, and 77 CATV channels are successfully demonstrated over 40 km single‐mode fiber links. Good performance of bit error rate, carrier‐to‐noise ratio, composite second order, and composite triple beat is achieved in our proposed bidirectional DWDM‐PON.     

Comparison of ion-pairing and ion-suppressing liquid chromatographic methods for the determination of pyrimethamine and ormetoprim in chicken feed

A high-performance liquid chromatographic (HPLC) method is developed to simultaneously determine pyrimethamine (PYR) and ormetoprim (OMT) in chicken feed. In the ion-pairing HPLC determination of PYR and OMT, the relation between the retention factor (k') and the concentration of the organic phase (acetonitrile) shows a characteristic curve. The k' value first decreases and then increases slowly with increasing concentrations of acetonitrile, but then increases rapidly when the acetonitrile concentration increases to 90%. Resolutions (Rs) of PYR and OMT decrease gradually when the concentration of organic phase increases. Increasing the concentration of the pairing ion sodium 1-octanesulfonate (PIC B-8) can decrease the k' and Rs values. Optimum values of k' and Rs are obtained using 82% acetonitrile in 0.005 M PIC B-8. In ion-suppressing HPLC, varying the concentration of Na2HPO4 has little effect on either the k' or Rs values of PYR or OMT at pH 7.5. However, at pH 4.0, k' and Rs decline when the concentration of Na2HPO4 increases. In general, ion-pairing HPLC generates more satisfactory results than ion-suppressing HPLC. Using 82% acetonitrile in water containing 0.001M PIC B-8 as the mobile phase, linear calibration curves are obtained in the range from 1 to 5 mg/L of PYR and OMT. Sulfamonomethoxine, sulfadimethoxine, sulfaquinoxaline, trimethoprim, amprolium, clopidol, and nicarbazin do not interfere with the detection of PYR or OMT. The recoveries of PYR from spiked feed at 1 and 5 mg/Kg are 73.0% and 72.0%, respectively, and those of OMT from spiked feed at 3 and 7 mg/Kg are 50.3% and 53.6%, respectively.     

Compact Planar Quasi-Elliptic Function Filter With Inline Stepped-Impedance Resonators

Compact microstrip bandpass filters of orders N = 4,6, and 8 with quasi-elliptic function responses are synthesized with inline stepped-impedance resonators. The filters have enhanced transition responses since two transmission zeros are generated on both sides of the passband. Existence of these two zeros is investigated by formulating the Y-matrix of the equivalent circuit for the filter and taking adjacent and nonadjacent coupling into account. Some matrix elements Y_j,j+2 representing coupling between two nonadjacent resonators are shown to have the opposite signs in both the lower and upper sides of the center frequency. This property leads to creation of the two transmission zeros on both sides of the passband. It is demonstrated that one more zero can be created in the rejection band by the tapped-line input/output scheme. Experimental circuits on substrates with epsiv_r = 2.2 and 10.2 are measured to validate the theory and design.