排序方式: 共有15条查询结果,搜索用时 15 毫秒
1.
S. V. Bobashev N. P. Mende P. A. Popov B. I. Reznikov V. A. Sakharov S. Z. Sapozhnikov V. Yu. Mityakov A. V. Mityakov D. A. Buntin A. A. Maslov H. Knauss T. Roediger 《Technical Physics Letters》2009,35(3):214-216
We present the results of comparative measurements of the heat flux to a flat plate in a supersonic flow at a Mach number of M = 6, which were performed using the two following anisotropic heat sensors with different thicknesses of sensor elements: (i) Atomic Layer Thermo Pile (ALTP, Fortech GmbH, Germany) with a thickness of ~0.5 × 10?6 m and (ii) gradient heat flux sensor (GHFS, St. Petersburg State Polytechnic University, Russia) with a thickness of ~2 × 10?4 m. The ALTP sensor can be used for directly measuring heat fluxes in processes with a characteristic time above 10?6 s. A method for mathematically processing the GHFS response signal is proposed that allows heat flux oscillations to be revealed in gasdynamic process with a characteristic time on the order of 10?4 s. 相似文献
2.
A stream of unheated crossflow air has been used to make finer melt-blown fibers. Not only are smaller average fiber diameters obtained, but the variation in fiber diameter is smaller. The use of this technique can allow the production of melt-blown nonwovens, which have finer fibers and more uniform webs. Since unheated air is used in the crossflow jet, the fiber enhancement in terms of finer, stronger fibers can be achieved with an energy savings by substituting unheated crossflow air for a portion of the primary air. 相似文献
3.
Injected 111 male ring doves intramuscularly with dexamethasone throughout a reproductive cycle in an attempt to suppress adrenocortical secretions. Ss were tested for initiation and maintenance of incubation behavior. Treated Ss showed normal initiation of sitting when observed in their cages, but when they were tested alone in novel cages initiation of incubation tended to be disrupted. Prolonged dexamethasone treatment interfered with maintenance of incubation behavior in both test situations. The deleterious effect of dexamethasone on maintenance of home cage sitting was alleviated by concurrent treatment with prolactin or ACTH. In conclusion, adrenal secretions do not seem to be necessary for onset of incubation in males, but there are hormonal requirements for maintenance of this behavior. (35 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
Ji Il Choi Ali Abdelhafiz Parker Buntin Adam Vitale Alex W. Robertson Jamie Warner Seung Soon Jang Faisal M. Alamgir 《Advanced functional materials》2019,29(46)
The nature of the atomic configuration and the bonding within epitaxial Pt‐graphene films is investigated. Graphene‐templated monolayer/few‐multilayers of Pt, synthesized as contiguous 2D films by room temperature electrochemical methods, is shown to exhibit a stable {100} structure in the 1–2 layer range. The fundamental question being investigated is whether surface Pt atoms rendered in these 2D architectures are as stable as those of their bulk Pt counterparts. Unsurprisingly, a single layer Pt on the graphene (Pt_1ML/GR) shows much larger Pt dissociation energy (?7.51 eV) than does an isolated Pt atom on graphene. However, the dissociation energy from Pt_1ML/GR is similar to that of bulk Pt(100), ?7.77 eV, while in bi‐layer Pt on the graphene (Pt_2ML/GR), this energy changes to ?8.63 eV, surpassing its bulk counterpart. At Pt_2ML/GR, the dissociation energy also slightly surpasses that of bulk Pt(111). Bulk‐like stability of atomically thin Pt–graphene results from a combination of interplanar Pt? C covalent bonding and inter/intraplanar metallic bonding. This unprecedented stability is also accompanied by a metal‐like presence of electronic states at the Fermi level. Such atomically thin metal‐graphene architectures can be a new stable platform for synthesizing 2D metallic films with various applications in catalysis, sensing, and electronics. 相似文献
5.
Neuronal activation was examined by fos immunohistochemistry in ring doves (Streptopelia risoria) reunited with their young after overnight separation. In an initial study, squab-exposed parents showed more fos immunoreactivity (ir) in the preoptic area (POA) and lateral hypothalamus (LH) than squab-deprived parents. In a 2nd study, parents allowed free access to young and those separated from young by a wire mesh partition showed more fos-ir in the POA, LH, and lateral septum than box-exposed controls. Contact with young also increased fos-ir in the medial preoptic nucleus and bed nucleus of the stria terminalis, but noncontact exposure did not. Conversely, nontactile squab exposure stimulated more fos-ir in the POA than did free access to young, which suggests POA involvement in appetitive aspects of parenting. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Gene C. Ulmer William Crawford Elliott Thomas Buntin Edwin S. Erickson Jr. John J. Friel 《Journal of the American Ceramic Society》1992,75(6):1476-1483
Pure fayalite liquid was reduced at 1300°C in variable C/H ratio gas mixtures, all with constant f O2 both with and without various cation additives that included Cr2 O3 , MnO, CaO, TiO2 , Al2 O3 , Na2 O, and K2 O. Similar studies were also performed on Carol Lake iron ore pellets without these cation additives. The role of cation additives in reduction with CO-rich gases is minimally important. In hydrogen-rich reduction studies, the reduction per hour was increased 50% by a 2.5 wt% addition of CaO, increased by about 75% by a 2.5 wt% addition of Cr2 O3 , and increased by about 50% for a 2.5 wt% addition of MnO as compared to the reduction rate of pure fayalite liquid. Much more dramatic than any cation additive effect is the role of the hydrogen content of the gas mixture. At 1300°C and a fixed –log f O2 = 13, the reduction per hour of pure fayalite liquid triples with the replacement of the CO by hydrogen even with just the first 10 vol% of hydrogen. Theoretical discussions of the role of cation additives and gas speciation on fayalite melt structure are presented. 相似文献
7.
Kathrin Buntin Kira J. Weissman Dr. Rolf Müller Prof. Dr. 《Chembiochem : a European journal of chemical biology》2010,11(8):1137-1146
The ajudazols are antifungal secondary metabolites produced by a hybrid polyketide synthase (PKS)‐nonribosomal peptide synthetase (NRPS) multienzyme “assembly line” in the myxobacterium Chondromyces crocatus Cm c5. The most striking structural feature of these compounds is an isochromanone ring system; such an aromatic moiety is only known from two other complex polyketides, the electron transport inhibitor stigmatellin and the polyether lasalocid. The cyclization and aromatization reactions in the stigmatellin pathway are presumed to be catalyzed by a cyclase domain located at the end of the PKS, while the origin of the lasalocid benzenoid ring remains obscure. Notably, the ajudazol biosynthetic machinery does not incorporate a terminal cyclase, but instead a variant thioesterase (TE) domain. Here we present detailed phylogenetic and sequence analysis, coupled with experiments both in vitro and in vivo, that suggest that this TE promotes formation of the isochromanone ring, a novel reaction for this type of domain. As the ajudazol TE has homologues in several other secondary‐metabolite pathways, these results are likely to be generalizable. 相似文献
8.
Maksimov VA Karataev SD Chernyshev AL Buntin SE Panaĭkin VI Lysov AN Zelentsov SN Obukhov IuV Parkhomenko NA Mel'nikov VL Shelelov EE 《Voprosy pitaniia》2007,76(6):33-38
The article is devoted to an effective not medicamentous method of therapy--to the medical starvation. Indications and contra-indications to carrying out of medical starvation are given. Own results of use of medical starvation are resulted at diseases of bodies of digestion. Practical recommendations on applications of medical starvation for patients with diseases of bodies of a gastroenteric path are submitted. 相似文献
9.
The results of an experimental study of the influence of local heating/cooling of a blunted cone nose-tip on the development of perturbations in the boundary layer for Mach number M = 6 are presented. A comparative analysis of the pressure-pulsation spectra on the cone surface has been carried out. It is shown that heating/cooling in the boundary layer of an acute cone leads to destabilization/stabilization of the perturbations of the second mode. For blunted cones, the opposite effect has been observed: heating leads to weak stabilization of disturbances, and cooling leads to destabilization. This effect is enhanced by increasing the bluntness radius of the cone nose-tip. 相似文献
10.
Physiological, Nutritional, and Biochemical Bases of Corn Resistance to Foliage-Feeding Fall Armyworm 总被引:1,自引:1,他引:0
Three corn (Zea mays) germplasm lines [i.e., Ab24E (susceptible control), Mp708 (resistant control), and a locally selected partial inbred line
FAW7050 (resistant)] were examined for Spodoptera frugiperda (J.E. Smith; Lepidoptera: Noctuidae) resistance. Nutritional [i.e., total protein content, amino acids, glucose, total nonstructural
carbohydrates (TNC), protein to TNC (P/C) ratios] and biochemical (i.e., peroxidase and lipoxygenase 3) properties in the
seedlings of these corn lines were examined to categorize resistance mechanisms to S. frugiperda. Physiological changes in photosynthetic rates also were examined in an attempt to explain nutritional and biochemical dynamics
among corn germplasm lines and between insect-infested and noninfested corn plants within a germplasm line. Results indicated
that S. frugiperda larvae survived better and developed faster in susceptible Ab24E than in resistant FAW7050 or Mp708. The three germplasm
lines differed in resistance mechanisms to S. frugiperda, and the observed patterns of resistance were probably collective results of the P/C ratio and defensive proteins. That is,
the susceptibility of Ab24E to S. frugiperda was due to a high P/C ratio and a low level of induced defensive compounds in response to insect herbivory, while the resistance
of FAW7050 resulted from elevated defensive proteins following insect herbivory, low P/C ratio, and elevated defensive proteins
in Mp708 contributed to its resistance to S. frugiperda. The elevated protein amounts in resistant Mp708 and FAW7050 following S. frugiperda injury were likely due to greater conversion of photosynthates to defensive proteins following the greater photosynthetic
rates in these entries. Greater photosynthetic capacity in Mp708 and FAW7050 also led to higher amino acid and glucose contents
in these two lines. Neither amino acid nor lipoxygenase 3 played a critical role in corn resistance to S. frugiperda. However, high inducibility of peroxidase may be an indicator of S. frugiperda susceptibility as observed elsewhere. 相似文献