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2.
The miscibility and phase behavior of ternary blends containing dimethylpolycarbonate (DMPC), tetramethylpolycarbonate (TMPC) and poly[styrene‐co‐(methyl methacrylate)] copolymer (SMMA) have been explored. Ternary blends containing polystyrene (PS) instead of SMMA were also examined. Blends of DMPC with SMMA copolymers (or PS) did not form miscible blends regardless of methyl methacrylate (MMA) content in copolymers. However, DMPC blends with SMMA (or PS) blends become miscible by adding TMPC. The miscible region of ternary blends is compared with the previously determined miscibility region of binary blends having the same chemical components and compositions. The region where the ternary blends are miscible is much narrower than that of binary blends. Based on lattice fluid theory, the observed phase behavior of ternary blends was analyzed. Even though the term representing the Gibbs free energy change of mixing for certain ternary blends had a negative value, blends were immiscible. It was revealed that a negative value of the Gibbs free energy change of mixing was not a sufficient condition for miscible ternary blends because of the asymmetry in the binary interactions involved in ternary blends. Copyright © 2004 Society of Chemical Industry 相似文献
3.
Discusses, from a personal point of view, experiments carried out to study the diffraction and propagation of VHF, HF and MF radio waves in the early-mid 1950s in the mountains of Alaska 相似文献
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We present a technique for in situ lens nucleus emulsification using low phaco power and high vacuum, a continuous curvilinear capsulorhexis, and hydrodelineation. Emulsification is done with the phaco tip slanted down 30 or 45 degrees. Cutting and aspiration do not cause an undesirable energy loss. This technique can be combined with the nuclear chopping or divide and conquer methods because of its ability to drill and hold the nucleus. Posterior capsular rupture is prevented because the separated epinucleus acts as a barrier between the nucleus and the cortex. The low power used minimizes the energy transfer to the corneal endothelium. This technique is particularly useful in eyes with brunescent cataract. 相似文献
6.
CK Damer J Partridge WR Pearson TA Haystead 《Canadian Metallurgical Quarterly》1998,273(38):24396-24405
Microcystin-affinity chromatography was used to purify 15 protein phosphatase 1 (PP1)-binding proteins from the myofibrillar fraction of rabbit skeletal muscle. To reduce the time and amount of material required to identify these proteins, proteome analysis by mixed peptide sequencing was developed. Proteins are resolved by SDS-polyacrylamide gel electrophoresis, electroblotted to polyvinylidene fluoride membrane, and stained. Bands are sliced from the membrane, cleaved briefly with CnBr, and applied without further purification to an automated Edman sequencer. The mixed peptide sequences generated are sorted and matched against the GenBank using two new programs, FASTF and TFASTF. This technology offers a simple alternative to mass spectrometry for the subpicomolar identification of proteins in polyacrylamide gels. Using this technology, all 15 proteins recovered in PP-1C affinity chromatography were sequenced. One of the proteins, PP-1bp55, was homologous to human myosin phosphatase, MYPT2. A second, PP-1bp80, identified in the EST data bases, contained a putative PP-1C binding site and a nucleotide binding motif. Further affinity purification over ATP-Sepharose isolated PP-1bp80 in a quaternary complex with PP-1C and two other proteins, PP-1bp29 and human p20. Recombinant PP-1bp80 also bound PP-1C and suppressed its activity toward a variety of substrates, suggesting that the protein is a novel regulatory subunit of PP-1. 相似文献
7.
D. Swenson 《Journal of Materials Science: Materials in Electronics》2007,18(1-3):39-54
Most lead-free solders comprise tin (Sn) as the majority component, and nominally pure β-Sn is the majority phase in the microstructure
of these solders. It is well established that nucleation of β-Sn from Sn-base liquid alloys is generally difficult. Delays
in the onset of β-Sn formation have a profound effect upon the microstructural development of solidified Sn-base alloys. Utilizing
stable and metastable phase diagrams, along with solidification principles, the effects of inhibited β-Sn nucleation on microstructural
development are discussed, employing the widely studied Sn–Ag–Cu (SAC) alloy as a model system. This analysis shows that the
main effect of suppressed β-Sn nucleation on near-eutectic SAC solders is to increase the number and/or volume fraction of
primary or primary-like microconstituents, while simultaneously decreasing the volume fraction of eutectic microconstituent.
General strategies are outlined for avoiding unwanted microconstituent development in these materials, including the use of
metastable phase diagrams for selecting alloy compositions, employment of inoculants to promote β-Sn nucleation, and utilization
of high cooling rates to limit solid phase growth. Finally, areas for future research on the development of inoculated Sn-base
solder alloys are outlined. 相似文献
8.
WS Ahn J Yoo SW Huh CK Kim JM Lee SE Namkoong SM Bae IP Lee 《Canadian Metallurgical Quarterly》2003,12(5):383-390
We investigated clinical efficacy of green tea extracts (polyphenon E; poly E and (-)-epigallocatechin-3-gallate [EGCG]) delivered in a form of ointment or capsule in patients with human papilloma virus (HPV) infected cervical lesions. Fifty-one patients with cervical lesions (chronic cervicitis, mild dysplasia, moderate dysplasia and severe dysplasia) were divided into four groups, as compared with 39 untreated patients as a control. Poly E ointment was applied locally to 27 patients twice a week. For oral delivery, a 200 mg of poly E or EGCG capsule was taken orally every day for eight to 12 weeks. In the study, 20 out of 27 patients (74%) under poly E ointment therapy showed a response. Six out of eight patients under poly E ointment plus poly E capsule therapy (75%) showed a response, and three out of six patients (50%) under poly E capsule therapy showed a response. Six out of 10 patients (60%) under EGCG capsule therapy showed a response. Overall, a 69% response rate (35/51) was noted for treatment with green tea extracts, as compared with a 10% response rate (4/39) in untreated controls (P<0.05). Thus, the data collected here demonstrated that green tea extracts in a form of ointment and capsule are effective for treating cervical lesions, suggesting that green tea extracts can be a potential therapy regimen for patients with HPV infected cervical lesions. 相似文献
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10.
Mickelson R.L. Swenson G.W. Jr. 《IEEE transactions on instrumentation and measurement》1991,40(5):816-819
Processes involving the cross-correlation of two noisy data streams are frequently encountered in signal processing. The performances of two commonly used correlators, the simple and complex correlators, are examined. The conventional view is that the complex correlator is superior to the simple correlator by a factor of the square root of two in output signal-to-noise ratio (SNR). However, by modifying the simple correlator to utilize all the available information, its performance is improved. The development of the modified correlator is explained, and a computer simulation shows that this modified correlator is approximately equivalent to the complex correlator in noise performance 相似文献