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排序方式: 共有32条查询结果,搜索用时 15 毫秒
1.
The authors demonstrate the application of a commercially available SiGe heterojunction bipolar transistor monolithic microwave integrated circuit technology to active mixers in future communication systems at 5.7 GHz and above. This technology can be used to realise circuits with less than 50 mW power consumption, conversion gains above 15 dB and small double sideband noise figures of 3.6 and 9.4 dB for 5.7 and 11.2 GHz Gilbert cell mixer circuits, respectively 相似文献
2.
��The Sinian pool of Weiyuan gasfield is a black one controlled by structure.In this paper,The producing performance of water's entering into gas wells is simply stated,the operation method of water-prod- ucing gas wells is summarized and the advantage or drawback of various technology of water withdrawal in gas production is also appraised,It is pointed out that using the technique of intensifying water withdrawal is an efficient way for synthetically administering and well developing this gas pool. 相似文献
3.
Farid Khallouki Roswitha Haubner Gerhard Erben Cornelia M. Ulrich Robert W. Owen 《Food chemistry》2012
Mirabelle plums represent a famous fruit from the Lorraine region, however little is known about their phytochemical composition. The oil of the fruit contained predominantly oleic acid (59%) and linoleic acid (29%). The total content of phenolic antioxidants in the whole fruits was 5.338 g/kg with 456 mg/kg (9%), 701 mg/kg (13%) and 4159 mg/kg (78%) detected in the peels, flesh and pits respectively. The peels contained solely 3,4-dihydroxybenzoic acid (270 mg/kg) and rutin (186 mg/kg), the flesh exclusively echinoids (723 mg/kg), whereas the pits contained a rich variety of phenolic compounds (4.2 g/kg) dominated by amygdalin (3.8 g/kg), but with significant contributions from vanillin (102 mg/kg), guajacyl-glycerin-coniferyl aldehyde isomers (87 mg/kg), dehydro-diconiferyl aldehyde (52 mg/kg), and vanillin diglucoside (48 mg/kg). Of the major phenolic compounds tested across a range of in vitro assays, rutin was the superior antioxidant. 相似文献
4.
The planning and design of a 50-kW experimental solar thermal power plant which was to have a selective coating on the absorber initiated an investigation into black chrome deposition in order to find the most suitable type of solution for a continuous plating process. Acetic acid-type and fluorosilic acid-type electrolytes were tested with a variety of additives and deposition parameters. The best results were achieved with an electrolyte containing fluorosilic acid as the catalyst. With this solution, coatings with optimum thermo-optical properties were formed in only 22 sec at current densities of 0.5 A cm−2 and a temperature of 15°C. These yielded values of 0.97 for total absorptance (AM2 spectrum) and 0.08 (100°C) for the thermal emittance on a basis of light Watts-type nickel. Other nickel undercoatings which were investigated produced less satisfactory results.Both the thermal stability of the plating up to temperatures of 400°C and the dependence of its IR emittance on temperature were investigated. The tubes coated in the way described have a uniform, matt-black appearance and the thermo-optical properties are constant along their whole length and round their whole circumference. 相似文献
5.
S Hagl W Heimisch H Meisner R Erben M Baum N Mendler 《Canadian Metallurgical Quarterly》1977,72(4):344-364
Hemodilution decreases blood viscosity and circulatory input impedance and thus reduces afterload. Its use in treatment of LV power failure has been advocated, but the safe limits of isovolemic hemodilution are not known. Compensation of the reduced O2-capacity of the blood was therefore studied with normal and impaired coronary reserve. In 20 dogs the LAD was stenosed to a degree just not affecting the supplied region and central and coronary hemodynamics were studied. Regional myocardial function was assessed by ultrasound transit time between transducers implanted in the LV wall. Lowering the hematocrit to 15% by isovolumic exchange of blood for Dextran 60 increased CVP (18%), PAP (47%), LAP (64%), LVedP (46%), CO (67%), and flow to the intact area (LCA: 211%). Flow in the stenosed LAD increased slightly. Enddiastolic length (EDL) of LAD dependent muscle segments rose to 120% and their contraction amplitude deltaL was decreased by 46%. Whereas non-ischemic segments showed compensatory rise in deltaL (38%) at almost constant EDL (+9%). After release of the LAD stenosis EDL and deltaL returned to normal. During progressive anemia myocardial O2-demand is not adequately met if coronary reserve capacity is depleted. Reversion of hypokinesia after removal of the stenosis shows unimpaired myocardial function at a hematocrit as low as 15% provided the coronary circulation is intact. 相似文献
6.
Aamer Saeed Muhammad Naeem Mustafa Muhammad Zain-ul-Abideen Ghulam Shabir Mauricio F. Erben Ulrich Flörke 《Journal of Sulfur Chemistry》2019,40(3):312-350
1-(acyl/aroyl)-3-(substituted)thioureas are exciting structures in the fields of organic synthesis, material sciences, and biomedical research. Of particular significance is the fact that acyl thiourea derivatives have been demonstrated to be highly exceptional ligands and their coordination compounds have extensively been investigated in the synthesis of pharmaceuticals and agrochemical ingredients. Moreover, these structural motifs are enjoying the prestigious status as versatile synthons in heterocyclic syntheses. Therefore, the progress to introduce functionalization on the backbone of 1-(acyl/aroyl)-3-(substituted)thioureas is highly desirable. This account summarizes our efforts to capture recent documented achievements by various research groups. 相似文献
7.
Jun Zhang Patrick Byers Amelie Erben Christine Frank Levin Schulte-Spechtel Michael Heymann Denitsa Docheva Heinz P. Huber Stefanie Sudhop Hauke Clausen-Schaumann 《Advanced functional materials》2021,31(19):2100066
Tissue engineering requires the precise positioning of mammalian cells and biomaterials on substrate surfaces or in preprocessed scaffolds. Although the development of 2D and 3D bioprinting technologies has made substantial progress in recent years, precise, cell-friendly, easy to use, and fast technologies for selecting and positioning mammalian cells with single cell precision are still in need. A new laser-based bioprinting approach is therefore presented, which allows the selection of individual cells from complex cell mixtures based on morphology or fluorescence and their transfer onto a 2D target substrate or a preprocessed 3D scaffold with single cell precision and high cell viability (93–99% cell survival, depending on cell type and substrate). In addition to precise cell positioning, this approach can also be used for the generation of 3D structures by transferring and depositing multiple hydrogel droplets. By further automating and combining this approach with other 3D printing technologies, such as two-photon stereolithography, it has a high potential of becoming a fast and versatile technology for the 2D and 3D bioprinting of mammalian cells with single cell resolution. 相似文献
8.
Larissa Erben Jacqueline P. Welday Ricardo Murphy Andres Buonanno 《International journal of molecular sciences》2022,23(16)
A popular approach to spatiotemporally target genes using the loxP/Cre recombination system is stereotaxic microinjection of adeno-associated virus (AAV) expressing Cre recombinase (AAV_Cre) in specific neuronal structures. Here, we report that AAV_Cre microinjection in the ventral tegmental area (VTA) of ErbB4 Cyt-1-floxed (ErbB4 Cyt-1fl/fl) mice at titers commonly used in the literature (~1012–1013 GC/mL) can have neurotoxic effects on dopaminergic neurons and elicit behavioral abnormalities. However, these effects of AAV_Cre microinjection are independent of ErbB4 Cyt-1 recombination because they are also observed in microinjected wild-type (WT) controls. Mice microinjected with AAV_Cre (1012–1013 GC/mL) exhibit reductions of tyrosine hydroxylase (TH) and dopamine transporter (DAT) expression, loss of dopaminergic neurons, and they behaviorally become hyperactive, fail to habituate in the open field and exhibit sensorimotor gating deficits compared to controls microinjected with AAV_GFP. Importantly, these AAV_Cre non-specific effects are: (1) independent of serotype, (2) occur with vectors expressing either Cre or Cre-GFP fusion protein and (3) preventable by reducing viral titers by 1000-fold (1010 GC/mL), which retains sufficient recombination activity to target floxed genes. Our studies emphasize the importance of including AAV_Cre-injected WT controls in experiments because recombination-independent effects on gene expression, neurotoxicity and behaviors could be erroneously attributed to consequences of gene ablation. 相似文献
9.
10.
Allyl molybdenum complex [(η3-C3H5)(η5-C5H5)Mo(CO)2] (Mo-A) was examined as a new drier for solvent-borne alkyd binder. The drying activity of pure Mo-A and the of combinations of Mo-A with cobalt(II) 2-ethylhexanoate (Co-Nuodex) was examined using standard methods for measurements of the drying time and hardness development of the alkyd film. The detailed study of the drying process was studied by time-resolved infrared spectroscopy on ethyl linoleate as well as on thin coating of alkyd binder. 相似文献