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161.
    
Conventional semiconductor‐based photomixers are limited by the carrier transit‐time‐roll‐off and the RC‐roll‐off of the device‐capacitance. We have developed a THz‐photomixer which can overcome both limitations and proves far superior to a conventional pin‐photomixer. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
162.
    
We report a new imaging diagnostic suitable for measurements of infrared-active molecules, namely infrared planar laser-induced fluorescence (IR PLIF), in which a tunable infrared source is used to excite vibrational transitions in molecules and vibrational fluorescence is collected by an infrared camera. A nanosecond-pulse Nd:YAG-pumped KTP/KTA OPO/OPA system is used to generate 12 mJ of tunable output near 2.35 μm which excites the 2ν band of carbon monoxide (CO); fluorescence resulting from excited CO is collected at 4.7 μm by using an InSb focal plane array. Quantitative, high-SNR PLIF imaging of gas-phase CO is demonstrated at a 10-Hz acquisition rate with a minimum detection limit of 1350 ppm at 300 K. Received: 30 July 1999 / Published online: 16 September 1999  相似文献   
163.
    
The elastic constants of cuprous oxide have been measured by a standard pulse echo technique. The low temperature limiting values of the stiffness moduli are (in units of 1011 dyn/cm2) C11 = 12.1 ± 0.5, C12 = 10.5 ± 0.4, C44 = 1.09 ± 0.03. The Debye temperature calculated from these is 181° K. Both shear moduli show an unusual increase with increasing temperature.  相似文献   
164.
165.
Diterpenoids     
This review covers the isolation and structures of diterpenoids including labdanes, clerodanes, pimaranes, abietanes, kauranes, cembranes, taxanes and marine diterpenoids; 173 references are cited.  相似文献   
166.
The structures and biosynthesis of the sesquiterpenoid metabolites of Botrytis cinerea and their relationship to the presilphiperfolanes are reviewed. The development of a novel strategy for the control of this phytopathogenic fungus based on analogues of these metabolites is described. There are 75 references.  相似文献   
167.
168.
Quantitative absorption spectra for several hydrocarbon fuels in the liquid phase at are presented. Measurements of toluene, n-dodecane, n-decane, and three samples of gasoline were made over the spectral region 2700–3200 to support the development of mid-infrared laser-absorption diagnostics for measurements of fuel vapor in the presence of liquid films and aerosols. A procedure for quantitative Fourier transform infrared (FTIR) absorption measurements of strongly absorbing liquids is described and the resulting absorption spectra are compared with previously measured absorption spectra in the vapor phase. The measured absorption spectra for liquid gasoline are shown to scale with the volume percent of olefin, alkane, and aromatic hydrocarbons in each sample. Finally, the observed frequency shift of in the spectra of vapor and liquid hydrocarbons is discussed, including the potential for measurements of fuel vapor in the presence of liquid films.  相似文献   
169.
As part of our ongoing project to develop new molecular probes for estrogen receptor-alpha, we are exploring the utility of internally-substituted asymmetric biphenyls as a proteomimetic scaffold. In this study, we describe synthetic methods for preparing the requisite substituted-bromophenol precursors, their further elaboration, and the subsequent Suzuki–Miyaura coupling of these sterically-hindered and electronically-rich aromatic systems. The results provide an efficient route with which to generate further libraries of novel asymmetric biphenyl compounds as potential proteomimetics.  相似文献   
170.
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