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101.
102.
In this article, we present a detailed theoretical analysis and a prototype implementation of a family of cameras designed with the explicit goal of detecting and removing interfering dynamic occluders in real time, during live capture, as opposed to fixing the resulting artifacts a posteriori. Such an early-acquisition approach improves efficiency: more valid samples are acquired faster without worrying about moving occluders. One option for designing a camera to be unaffected by moving occluders is to sample through the occluder, but true x-ray-like vision is technically impractical. Another option is to sample around the occluder using a camera with a large effective aperture, but such an approach requires a bulky acquisition device. Yet another possibility of sampling around an occluder is to rely on second and higher order reflected rays that indirectly sample surfaces not directly visible. However, devising an acquisition device sufficiently sensitive and efficient to capture large environments using reflected rays will remain challenging for the foreseeable future.  相似文献   
103.
Daniel Bouche 《电信纪事》1992,47(9-10):400-412
We study the creeping waves propagating on a convex object, whose surface impedance is Z. To this end, we seek, by using an asymptotic expansion method, a solution of Maxwell equations, propagating along a geode sic, and satisfying Silver-Müller radiation condition at infinity, and the impedance boundary condition at the surface of the body. By using a geodesic coordinate system suited to the problem, we obtain a closed form solution. The electric and magnetic fields are given in term of the components of these fields along the binormal to the geodesic. We show that two types of creeping waves exist: the electric (resp. magnetic) type, with a non zero binormal component of the electric (resp magnetic) field. They are uncoupled, except in the vicinity of Z = 1, where a rotation of the polarization, similar to Rytov’s law, is evidenced.  相似文献   
104.
Hemispheric involvement in reasoning abilities has been debated for some time, and it remains unclear whether the right hemisphere's involvement in problem solving is modality specific or dependent on the type of spatial reasoning required. In the current study, 2 types of nonverbal reasoning abilities were examined, spatial reasoning and proportional reasoning, in 109 patients with cerebrovascular disease that was confined to either the right or the left hemisphere or was diffuse in nature. Results indicated that no lateralizing effects were present based on type of spatial reasoning. Findings are consistent with the suggestion that higher order cognitive processes involved in nonverbal abstraction and problem solving are not strongly lateralized to the right hemisphere but rather are more generally distributed throughout the cortex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
105.
Adding environments as first-class entities to a language can greatly enhance its expressiveness. But first-class environments rely on identifiers, the syntax of variables, and thus do not mesh well with lexically-scoped languages. We present first-class extents as an alternative. First-class extents are founded upon lexical variables with dynamic extent. They are defined directly on the variables themselves rather than on their syntax. They therefore do not cause variable name capturing problems that plague first-class environments. Moreover, distinguishing variables from locations allows first-class extents to be orthogonal to imperative and control features.  相似文献   
106.
We study a 3-band model of CuO2 with “bare bones” interactions: hopping from copper ions to nearest-neighbor oxygenst pd only, a two-body interaction on the copper ionsU dd only, and an overlap copper-oxygen parameter λpd. In the limitt pdU dd 1/2→∞, t*=t pd 2/2U dd is the unit of energy with 8λpd 2 as the only parameter of significance. If the two-body interaction is invariant under particle-hole interchange, the low-lying states (energy O(t*)) can be described by conserved particles and can all be classified. They are quite distinct from the high-lying states (energies O(U dd)). The dynamics of the conserved fermion-like elementary particles are well described by a modifiedt-J model with extended hopping and nearest-neighbor superexchange attraction. This is a scenario known to be favorable to high-temperature superconductivity, but it must be noted that both the hopping range and the exchange are functions of 8λpd 2. Moreover, if the Hamiltonian isnot invariant under particle-hole interchange the dynamics becomes much more complex and possibly more inimical to high-temperature superconductivity. This may provide an explanation for the deleterious effect on superconductivity of very small concentrations of certain impurities.  相似文献   
107.
    
In diethyl ether extracts from celeriac (Apium graveolens L. var.rapaceum) all four stereoisomers of (3a–7a)-cis-3-butylhexahydrophthalide were found to be present. The analyses were carried out by means of GC, enantioselective GC and GC-MS. The assignment of the relative configuration of the diastereomers3 and4 was accomplished by NOE difference spectroscopy.
  相似文献   
108.
The authors present an original analysis of an aperture-coupled microstrip antenna. The theory is based on the segmentation method, which considers the patch as a multiport network whose impedance matrix is deduced from a hybrid matrix, and the use of analytical expressions of the cavity admittance at the slot centre. The theory is presented for the first time, and the theoretical results are in good agreement with previous published measurements  相似文献   
109.
110.
The beta subunit of human chorionic gonadotropin is potentially encoded by six genes, which can be categorized into two types based on a sequence change at codon 117: GCC for the type I and GAC for the type II genes. We previously showed that, whereas type I genes were exclusively expressed in normal breast tissues, expression of type II genes was associated with malignant transformation (Bellet, D., et al. Cancer Res., 57: 516-523, 1997). We designed a simple and robust test (the CG117 assay) that measures the percentage of type II over both types of chorionic gonadotropin beta mRNAs. Normal breast tissues consistently had a negative CG117 index, whereas cancer breast tissues showed indexes ranging from 0 to 100%. The prognostic significance of the CG117 index was investigated in a series of 99 unilateral invasive primary breast cancer patients with known long-term outcome (median follow-up, 9 years). The CG117 index was positive in 48 (48.5%) of the 99 tumor mRNA samples. The index was not significantly associated with standard prognostic parameters, including clinical and macroscopic tumor size, histopathological grade, and lymph node status or steroid receptor status. Patients with a positive CG117 index in primary tumor mRNA had significantly shorter metastasis-free survival (P = 0.014) and overall survival (P = 0.038) after surgery, compared to patients with a negative index. The prognostic significance of the CG117 index persisted in Cox multivariate regression analysis, both for metastasis-free survival (P = 0.008) and overall survival (P = 0.016), together with lymph node status (P = 0.027 and P = 0.009, respectively). These findings indicate that the CG117 index may contribute to the identification of high-risk breast cancer patients.  相似文献   
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