Ignition of composite propellant at subatmospheric pressures by means of carbon dioxide laser

Ignition behavior of solid propellant composed of 25 wt% polybutadiene and 75% ammonium perchlorate under subatmospheric conditions has been studied using a carbon dioxide laser whose radiant flux is uniformalized. Data of ignition time in Ar, N₂ and He atmospheres, and critical radiant flux and pressures over which ignition might be achieved, were obtained. Moreover, the data were compared with theoretical values, taking account of variable heat conductivity for the ambient gases with a surface ignition hypothesis. It is concluded that these ambient gases participate in the pre- and post-ignition reactions and the ignition preventive behavior of He atmosphere is not predictable merely based on its high transport properties. The detailed observation of the ignition transient near the critical pressure revealed that the ignition in Ar atmosphere occurs in gas phase under less than 100 torr whereas in He atmosphere it occurs always at the condensed phase surface.     

High performance liquid chromatographic analysis of 1-alkyl-2-acyl- and 1-alkyl-3-acyl-sn-glycerols

A high performance liquid chromatographic (HPLC) method is described for separation and quantitation of 1-alkyl-3-acyl- and 1-alkyl-2-acyl-sn-glycerol, products of the detritylation reaction of 1-alkyl-2-acyl-3-trityl-sn-glycerol. The alkyl glycerides were separated on a 25 cm×4.6 mm ID column packed with ∼5–6 μm silica and eluted isocratically with isooctane/isopropanol (98∶2, v/v) as mobile phase. The good separation and linear refractive index (RI) detector responses using cholesterol as an internal standard indicated the applicability of the method not only for the quantitative determination of the alkylglycerols but also for their semipreparative isolation. This HPLC method shows excellent reproducibility and accuracy and is applicable to other types of glycerides such as mono- and diacylglycerols. Presented in part at the AOCS annual meeting, Honolulu, Hawaii, May 1986.     

Replication errors in hematological neoplasias: genomic instability in progression of disease is different among different types of leukemia

Genetic alteration, including genomic instability, is an ultimate step toward the malignant process. One approach to delineating replication errors in cancer cells is to determine the alterations of microsatellites, which are short, repeated nucleotide sequences existing throughout the genomes. We used a fluorescent system to assess microsatellite changes in seven loci (D2S123, D3S643, D5S107, LPL, D17S261, TP53, and D18S34) of 73 consecutive patients with various hematological neoplasias. De novo acute leukemia patients had a low frequency (<1%) of microsatellite alterations at each locus, and none of them demonstrated multiple microsatellite changes. In chronic myeloid leukemia patients, no microsatellite instability was detected in the chronic phase, whereas a relatively high frequency (25%) of multiple microsatellite changes was evident in the blastic phase, and half of these patients had multiple microsatellite changes. About 50% of the patients with myelodysplastic syndrome (MDS) and post-MDS acute myeloid leukemia (post-MDS AML) had microsatellite alterations. We next compared microsatellite alterations in two different hematological phases (MDS and post-MDS AML phases); 5 of 11 patients with post-MDS AML had de novo appearance of microsatellite instability during disease progression. This indicates that genomic instability at multiple microsatellite loci could occur either before or after leukemic transformation in MDS patients. We concluded that genomic instability in chronic myeloid leukemia might be linked to blastic transformation in combination with cytogenetic changes. In contrast, MDS patients had replication errors as a relatively early genetic event as well as a late genetic event. These results suggest that the involvement of genomic instability in the progression of disease is different among various types of leukemia.     

An improved procedure for the detritylation of 1-alkyl 2-acyl 3-trityl-sn-glycerols

The effects of experimental conditions and acid catalysts on the removal of the trityl group of 1-alkyl-2-acyl-3-trityl-sn-glycerols to yield 1-alkyl-2-acyl-sn-glycerols have been investigated. Removal of the trityl protecting group was complicated by the concomitant migration of the 2-acyl moiety to yield the 1-alkyl-3-acyl-sn-glycerol isomer. The course of detritylation as well as the extent of the 2-acyl to 3-acyl migration under the various conditions used were followed by high performance liquid chromatography (HPLC). Optimum yields of the desired 1-alkyl-2-acyl-sn-glycerol (}90%) were obtained with a molar equivalent of boron trifluoride-methanol in methylene chloride at 22 C for five min. Presented in part at the AOCS meeting in Honolulu, Hawaii, in May 1986.     

Quantum Query Complexity of Almost All Functions with Fixed On-set Size

This paper considers the quantum query complexity of almost all functions in the set \({\mathcal{F}}_{N,M}\) of \({N}\)-variable Boolean functions with on-set size \({M (1\le M \le 2^{N}/2)}\), where the on-set size is the number of inputs on which the function is true. The main result is that, for all functions in \({\mathcal{F}}_{N,M}\) except its polynomially small fraction, the quantum query complexity is \({ \Theta\left(\frac{\log{M}}{c + \log{N} - \log\log{M}} + \sqrt{N}\right)}\) for a constant \({c > 0}\). This is quite different from the quantum query complexity of the hardest function in \({\mathcal{F}}_{N,M}\): \({\Theta\left(\sqrt{N\frac{\log{M}}{c + \log{N} - \log\log{M}}} + \sqrt{N}\right)}\). In contrast, almost all functions in \({\mathcal{F}}_{N,M}\) have the same randomized query complexity \({\Theta(N)}\) as the hardest one, up to a constant factor.     

Ultra‐high‐resolution 1058‐ppi OLED displays with 2.78‐in size using CAAC‐IGZO FETs with tandem OLED device and single OLED device

We fabricated new 2.78‐in 1058‐ppi organic light‐emitting diode (OLED) displays. The displays used OLED devices with a tandem structure and a single structure and a field effect transistor (FET) using c‐axis aligned crystalline In–Ga–Zn–O (CAAC‐IGZO) for an active layer and employing the 1.5‐µm rule over a glass substrate. Even in the displays with such high resolution exceeding 1000 ppi, crosstalk that was observed in the lower luminance region was suppressed. The displays achieved high color reproducibility and reduced viewing angle dependence.     

Poly(p-substituted phenylacetylene) with perfluoroalkyloxydimethylsilyl side groups for oxygen and ethanol permselective membrane

Summary p-(1H,1H,2H,2H-perfluorodecyloxydimethylsilyl)phenylacetylene(ACf8) and p-(1H,1H,2H,2H-Perfluorohexyloxydimethylsilyl)phenylacetylene(ACf4) were synthesized and copolymerized with p-trimethylsilylphenylacetylene(ASi). The resulting copolymers, copoly(ACf8/ASi) and copoly(ACf4/ASi), were fabricated to tough membranes showing high oxygen permeabilities(Po ₂) of 10^-8 cc(STP)·cm/cm²·s·cmHg and high oxygen permselectivities(=Po ₂/Pn ₂) of more than 2.7. In particular, a copoly(ACf4/ASi) containing 15.1 mol% of ACf4 unit showed the best result: Po ₂=3.51x10^-8 cc(STP)·cm/cm²·s·cmHg and =3.04. The values were in a top level and very close to those of upper bound line in an -Po ₂ plot of data in the literature. In addition, copoly(ACfn/ASi) membranes were ethanol permselective owing to water repellency of the perfluoroalkyl groups. Copoly(ACf4/ASi) membranes showed better oxygen and ethanol permselectivity than copoly(ACf8/ASi) membranes.     

Dehydrohalogenation during pyrolysis of brominated flame retardant containing high impact polystyrene (HIPS-Br) mixed with polyvinylchloride (PVC)

Dehydrohalogenation during pyrolysis of brominated flame retardant containing polystyrene (brominated high impact polystyrene (HIPS-Br)) mixed with polyvinylchloride (PVC) was carried out in a laboratory scale batch process. Thermal and catalytic degradation of HIPS-Br mixed with PVC on carbon composite of iron oxide (TR-00301) catalyst was investigated. The thermal degradation of waste plastics (HIPS-Br/PVC) yielded liquid products with 55,000 ppm bromine and 4300 ppm chlorine content in oil. Catalytic degradation (4 g; TR-00301) of HIPS-Br/PVC waste plastics at 430 °C produced halogen-free clean oil, which can be used as a fuel oil or chemical feedstock. The main liquid products during catalytic degradation were benzene, toluene, styrene, ethyl benzene, α-methyl styrene, butyl benzene, 1,2-dimethyl benzene etc. The average carbon number of the liquid products produced during catalytic degradation (9.3) of waste plastics was less than that of the thermal degradation (10.4) and the density of liquid products was found to be lower during the catalytic degradation than the thermal degradation. The possibility of a single step catalytic process for the conversion of halogenated waste plastics into fuel oil with the simultaneous removal of chlorine and bromine content from the oil was demonstrated.