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1.
Vito Gigante Laura Aliotta Maria Beatrice Coltelli Patrizia Cinelli Luigi Botta Francesco Paolo La Mantia Andrea Lazzeri 《Journal of polymer science. Part A, Polymer chemistry》2020,58(23):3264-3282
The development of biodegradable materials for tailored applications, particularly in the field of polymeric films and sheets, is a challenging technological goal as well as a contribution to help protect the environment. Poly(lactic) acid (PLA) is a promising substitute for several oil-based polymers; however, to overcome its thermal and mechanical drawbacks, researchers have developed solutions such as blending PLA with polybutylene adipate terephthalate (PBAT), which is capable of increasing the ductility of the final material. In this study, PLA/PBAT binary blends, with minimum possible content of nonrenewable materials, were examined from processing, thermal, morphological, and rheological perspective. An optimized PLA/PBAT ratio was chosen as the polymeric basis to obtain a biodegradable formulation by adding a biobased plasticizer and appropriate fillers to produce a micrometer film with tailored flexibility and tear resistance. The processing technology involved flat-die extrusion, followed by calendering. The tearing resistance of the produced film was investigated, and the results were compared with literature data. A study on the essential work of fracture was implemented to explore the mode III out-of-plane fracture resistance starting from a trouser tear test. 相似文献
2.
Vincenzo Santagada Ferdinando FiorinoElisa Perissutti Beatrice SeverinoSara Terracciano Giuseppe CirinoGiuseppe Caliendo 《Tetrahedron letters》2003,44(6):1145-1148
A novel and convenient microwave-assisted dimerization of an active peptide compound using the DKPs as scaffold is described. The key reaction giving rise to the diketopiperazine scaffold is the intermolecular coupling. No epimerization was detected in the reactions used. Conventional and microwave heating of the reactions are compared. Synthesis by microwave irradiation gave the desired compounds in higher yields and in shorter reaction times than those obtained by conventional heating. 相似文献
3.
4.
D. Kast A. Jungclaus K.P. Lieb M. Górska G. de Angelis P.G. Bizzeti A. Dewald C. Fahlander H. Grawe R. Peusquens M. De Poli H. Tiesler 《The European Physical Journal A - Hadrons and Nuclei》1998,3(2):115-128
In the neutron deficient isotopes 104,105In lifetimes of high spin states in the range from 0.5 ps to 600 ps have been measured in a coincidence recoil distance Doppler
shift (RDDS) experiment. By combining the Doppler shift attenuation (DSA) and RDDS methods at few μm flight distances, the
problem of delayed feeding has been avoided and very short lifetimes in the range 0.5–0.8 ps have been determined. Shell model
calculations with strong restrictions for the neutron orbitals reveal good agreement with experimental level energies and
still fair agreement for most measured B(M1) and B(E2) values.
Received: 30 June 1998 相似文献
5.
The complexity of searching minimum difference covers, both in Z+ and in Zn, is studied. We prove that these two optimization problems are NP-hard. To obtain this result, we characterize those sets—called extrema—having themselves plus zero as minimum difference cover. Such a combinatorial characterization enables us to show that testing whether sets are not extrema, both in Z+ and in Zn, is NP-complete. However, for these two decision problems we exhibit pseudo-polynomial time algorithms. 相似文献
6.
7.
K. Schiffer A. Dewald A. Gelberg R. Reinhardt K. O. Zell Sun Xianfu P. v. Brentano 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(4):487-488
The K=3/2 1 T rotational band has been identified in99Y with a band-head energy of 536 keV. This result is in contradiction with previously reported data, but is in agreement with predictions of the IBFM/PTQM model. 相似文献
8.
For the assignment of the configuration at C(8) and C(15) of the natural oviposition-deterring pheromone 1 in Rhagoletis cerasi L., the four possible stereoisomers of 1 are synthesized. By condensing the C6 building blocks (5R)- 4 and (5S)- 4 with the boron enolates of the C10 building blocks (4S)- 13 and (4R)- 13 , followed by decarboxylative dehydration, all stereoisomers of 16 are available (Scheme 5). Glucosylation of 16 followed by formation of the taurin amide gives, after deprotection, the four stereoisomers (8R,15S)- 1 , (8R,15R)- 1 , (8R,15S) -1 , and (8S,15S)- 1 (Scheme 6). 相似文献
9.
Pierfrancesco Bravo Calimero Ticozzi Beatrice Pelli Pietro Traldi 《Journal of heterocyclic chemistry》1988,25(2):685-688
The mass spectrometric behavior of 3-methyl-3-hydroxybenzoxocines has been studied in detail by means of linked scans and mass analyzed ion kinetic energy spectrometry. The structure of the molecular ion and the fragmentation processes are strictly related to the structure of the neutral moieties. The possible isomerization of 3-hydroxy-10-methoxy-3-methyl-3,4,5,6-tetrahydro-2H-[1]benzoxocine to 2-methyl-2-[3-(3′-methoxy-2′-hydroxy)phenyl]pentyloxirane and to 2-hydroxymethyl-9-methoxy-2-methyl-2,3,4,5-tetrahydro[1]benzoxepine is investigated. 相似文献
10.
IN VIVO CHLOROPHYLL a FLUORESCENCE TRANSIENTS AND THE CIRCADIAN RHYTHM OF PHOTOSYNTHESIS IN GONYAULAX POLYEDRA 总被引:1,自引:0,他引:1
Beatrice M. Sweeney ‡ Barbara B. Prkzelin‡ Daniel Wong‡ Govindjee ‡ 《Photochemistry and photobiology》1979,30(2):309-311
Abstract— The intensity of chlorophyll a fluorescence during the early part of fluorescence induction at O , initial fluorescence, and P, peak fluorescence, was higher during the day phase of the circadian cycle than during the night phase in continuous light (LL) conditions and was positively correlated with the rate of oxygen evolution. The circadian rhythm in fluorescence in LL persisted in the presence of 10μM 3–(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), which blocks electron flow from photo-system (PS) II in photosynthesis. The rhythmic changes in fluorescence intensity are consistent with a lower rate constant for radiationless transitions during the day phase than during the night phase of the circadian rhythmicity. The circadian changes in the intensity of fluorescence were abolished at 77K, which may indicate the importance of structural changes in membranes in circadian oscillations. 相似文献