排序方式: 共有44条查询结果,搜索用时 15 毫秒
31.
It is shown that for every ε∈(0,1), every compact metric space (X,d) has a compact subset S?X that embeds into an ultrametric space with distortion O(1/ε), and $$\dim_H(S)\geqslant (1-\varepsilon)\dim_H(X),$$ where dim H (?) denotes Hausdorff dimension. The above O(1/ε) distortion estimate is shown to be sharp via a construction based on sequences of expander graphs. 相似文献
32.
Lauren N. Grant Prof. Balazs Pinter Brian C. Manor Prof. Dr. Hansjörg Grützmacher Prof. Dr. Daniel J. Mindiola 《Angewandte Chemie (International ed. in English)》2018,57(4):1049-1052
The first example of the OCPPCO ligand, diisophosphaethynolate, is reported via reductive coupling of a Sc?OCP precursor. Upon reduction with KC8, isolation of the dinuclear complex, namely [K(OEt2)]2[(nacnac)Sc(OAr)]2(OCPPCO), is observed, leading to a unique motif [OCPPCO]4?, stabilized by two scandium centers. Detailed NMR spectra of all complexes as well as IR and single crystal X‐ray studies were obtained to fully elucidate the nature of these complexes in solution as well as in the solid state. Theory is combined to probe the electronic structure and orbitals responsible for the bonding interactions in the Sc?OCPPCO?Sc skeleton but also to compare to the linear mode observed in the precursor. 相似文献
33.
Orly Manor 《商业与工业应用随机模型》1998,14(3):229-240
A Bernoulli thinning of a Markov renewal process is investigated. The properties of the thinned process are considered and are related to the properties of the original process. The parameters, moments and equilibrium of the thinned process are determined in terms of the parameters defining the underlying Markov renewal process. Results are illustrated by examples. © 1998 John Wiley & Sons, Ltd. 相似文献
34.
The polarity pattern of a macromolecule is of utmost importance to its structure and function. For example, one of the main driving forces for protein folding is the burial of hydrophobic residues. Yet polarity remains a difficult property to measure experimentally, due in part to its non-uniformity in the protein interior. Herein, we show that FTIR linewidth analysis of noninvasive 1-(13)C=(18)O labels can be used to obtain a reliable measure of the local polarity, even in a highly multi-phasic system, such as a membrane protein. We show that in the Influenza M2 H(+) channel, residues that line the pore are located in an environment that is as polar as fully solvated residues, while residues that face the lipid acyl chains are located in an apolar environment. Taken together, FTIR linewidth analysis is a powerful, yet chemically non-perturbing approach to examine one of the most important properties in proteins - polarity. 相似文献
35.
Dr. Devrani Mitra Dr. Hideaki Ogata Prof. Wolfgang Lubitz Brian C. Manor Prof. Thomas B. Rauchfuss Dr. Deborah Byrne Dr. Violaine Bonnefoy Prof. Francis E. Jenney Jr. Prof. Michael W. W. Adams Dr. Yoshitaka Yoda Dr. Ercan Alp Dr. Jiyong Zhao Prof. Stephen P. Cramer 《Angewandte Chemie (International ed. in English)》2013,52(2):469-469
36.
Liane M. Moreau Ekaterina Lapsheva Jorge I. Amaro-Estrada Michael R. Gau Patrick J. Carroll Brian C. Manor Yusen Qiao Qiaomu Yang Wayne W. Lukens Dimosthenis Sokaras Eric J. Schelter Laurent Maron Corwin H. Booth 《Chemical science》2022,13(6):1759
This study presents the role of 5d orbitals in the bonding, and electronic and magnetic structure of Ce imido and oxo complexes synthesized with a tris(hydroxylaminato) [((2-tBuNO)C6H4CH2)3N]3− (TriNOx3−) ligand framework, including the reported synthesis and characterization of two new alkali metal-capped Ce oxo species. X-ray spectroscopy measurements reveal that the imido and oxo materials exhibit an intermediate valent ground state of the Ce, displaying hallmark features in the Ce LIII absorption of partial f-orbital occupancy that are relatively constant for all measured compounds. These spectra feature a double peak consistent with other formal Ce(iv) compounds. Magnetic susceptibility measurements reveal enhanced levels of temperature-independent paramagnetism (TIP). In contrast to systems with direct bonding to an aromatic ligand, no clear correlation between the level of TIP and f-orbital occupancy is observed. CASSCF calculations defy a conventional van Vleck explanation of the TIP, indicating a single-reference ground state with no low-lying triplet excited state, despite accurately predicting the measured values of f-orbital occupancy. The calculations do, however, predict strong 4f/5d hybridization. In fact, within these complexes, despite having similar f-orbital occupancies and therefore levels of 4f/5d hybridization, the d-state distributions vary depending on the bonding motif (Ce O vs. Ce N) of the complex, and can also be fine-tuned based on varying alkali metal cation capping species. This system therefore provides a platform for understanding the characteristic nature of Ce multiple bonds and potential impact that the associated d-state distribution may have on resulting reactivity.Ce(iv) complexes with multiple bonds display similar f0 fractions, but different f/d hybridization, 5d-orbital energies, and TIP levels. 相似文献
37.
G. Manor 《Journal of Terramechanics》1995,32(2)
Current crop production schemes fail to offer the economic potential for reduced costs, increased yields and improved product quality, that could be derived from controlled traffic farming techniques utilizing multipurpose overhead mechanical frames. The development of new field machine technology will integrate total production under a single linear-travel system. This new technology is vital to reduce soil compaction with significantly decreased crop yield under irrigated, intensive-production conditions. This new machine technology will allow advanced chemical spray application techniques with enclosed shrouds for minimum drift. Precision planting, cultivating, plastic laying, irrigating, chemigating, harvesting (manual or mechanized) and materials handling will be accomplished by this technology. Onboard packing of more mature and thus more flavored vegetables with maximum nutrients will increase quality, reduce post-harvest losses, expand consumer acceptance and improve grower profit. Such a system could eventually serve as an automatic carrier for robot devices that would selectively harvest crops. The possibility of using electric power for this system offers higher economical potential, especially when using off-peak electricity. A versatile carriage drive with integral tool bar and hitch to mount implements, harvest elements and perform all operational functions for crop production, is an essential part of the system. Conveyors running along the mainframe will convey the yields gently out of the field. eliminating the large and heavy containers used on existing harvesting machines. 相似文献
38.
Robert A Creswell P.J Manor R.A Assink R.H Schwendeman 《Journal of Molecular Spectroscopy》1977,64(3):365-375
The microwave spectrum of oxiranecarboxaldehyde (glycidaldehyde) has been studied in the 8–40 GHz region. Transitions in the ground and first seven excited states of the torsional motion of the aldehyde group have been assigned for the species with the oxygen atom of the aldehyde group trans to the oxirane ring. The v = 0 to v = 1 torsional excitation energy is estimated to be 140 ± 10 cm?1. The population of any other torsional conformer is less than 5% of the trans species at 200 K. Structural parameters were derived from rotational constants of the three singly substituted 13C species, whose spectra were observed in natural abundance. Substitution parameters are , , ∠CCC = 119.8 ± 2.0°. The dipole moments determined by means of the Stark effect are μa = 1.932 ± 0.005 D, μb = 1.511 ± 0.017 D, and μc = 0.277 ± 0.156 D, with μt = 2.469 ± 0.031 D. 相似文献
39.
S. Sideman N. Lotan A. Tabak D. Manor L. Mor U. Taitelman J. Brook A. Tzipiniuk 《Applied biochemistry and biotechnology》1984,10(1-3):167-182
Composite beads of approximately 1mm diameter, made of cross-linked agarose and containing Fuller’s Earth or zirconium oxide
powders, were prepared and used in extracorporeal systems for blood detoxification. The former was used for the removal of
Paraquat, while the latter was used to remove inorganic phosphate from hyper-phosphatamic animals with or without acute renal
failure. The high surface area of the powder, combined with the low resistance to diffusion in the cross-linked agarose matrix,
are highly advantageous. The crosslinking provides high mechanical strength, heat stability, prolonged shelf life, good blood
flow characteristics, and prevents the release of fine particles into the blood.
Crosslinked agarose beads of 1 mm diameter, containing chemically-bound heparin were also prepared, and used as a model for
direct contact removal of LDL-cholesterol from the blood of familial hypercholesterolemic patients by hemoperfusion. The high
capacity of these beads (over 5 mg LDL/mL beads) indicates that this clinical modality can replace the highly expensive plasmapheresis
procedure presently used. 相似文献
40.