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81.
82.
Power-distribution networks need to provide impedance response with specified shape/value over a wide frequency band. Bypass capacitors with different values, and capacitors and planes may create resonance peaks, unless the capacitor parameters are selected properly. Distributed matched bypassing (DMB) is suggested to create a smooth impedance profile. DMB requires components with Q/spl Lt/1, which in turn requires user-defined ESR. Different options are shown to set (increase) the ESR of bypass capacitors. The concepts of bypass quality factor (BQF) and bypass resistor (BR) are introduced.  相似文献   
83.
Villeneuve  B. Cyr  N. Tetu  M. 《Electronics letters》1988,24(12):736-737
The possibility of building multiwavelength coherent communication systems based on low-cost semiconductor lasers in the 0.8 μm range locked to rubidium linear absorption is investigated. The values of frequency offset between the resonances of both the D2 (780 nm) and D1 (794.7 nm) lines are considered. A simple two-carrier FDM set-up using three resonances of the D2 line is presented and the optical frequency offsets are measured  相似文献   
84.
Ground-granulated blast-furnace slags (GGBS) are glasses (>99%) of the CaO-Al2O3-SiO2 compositional system and are widely used as supplementary cementitious materials. Differences in reactivity of GGBS were screened by modifying the content of 12 minor elements (namely Ba, Ce, Cs, Cr, K, Mn, P, Sn, Sr, Ti, V, and Zr). Scanning electron microscopy observations showed that most elements entered the silicate glass matrix, only Sn was reduced to its metallic form and P accumulated in minor minerals. Mortar strength tests showed that 2 day compressive strength was reduced by >50% for a TiO2 content of 2.5 wt% in the slag. At 28 days the loss in compressive strength was still >40%. Calorimetric tests on other element additions showed that the content of network modifiers (Ba, Cs, K and Sr) and GGBS reactivity are positively correlated, whereas Ce, Cr, V, and Zr significantly decreased reactivity. Finally, it is shown that these effects can be estimated by the concentration and the weighted field strength of the added element.  相似文献   
85.
To investigate the dynamics of online persuasion, this research uses the Elaboration Likelihood Model (ELM) to determine the effects of argument quality as a central route to influence attitude change versus design and social elements as peripheral routes to attitude change. Additional to this research is an examination of change in issue involvement as a mediator between central and peripheral routes leading to attitude change. Findings from a study involving 403 participants add to our understanding of ELM concerning the role of website design and how an individual’s level of issue involvement is a prerequisite to changing user attitudes.  相似文献   
86.
Non-alcoholic steatohepatitis (NASH) is a severe form of non-alcoholic fatty liver disease that is growing in prevalence. Symptoms of NASH become apparent when the disease has progressed significantly. Thus, there is a need to identify biomarkers of NASH in order to detect the disease earlier and to monitor disease severity. The inflammasome has been shown to play a role in liver diseases. Here, we performed a proof of concept study of biomarker analyses (cut-off points, positive and negative predictive values, receiver operating characteristic (ROC) curves, and likelihood ratios) on the serum of patients with NASH and healthy controls on apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), interleukin (IL)-18, Galectin-3 (Gal-3), and C-reactive protein (CRP). ASC, IL-18, and Gal-3 were elevated in the serum of NASH patients when compared to controls. The area under the curve (AUC) for ASC was the highest (0.7317) with an accuracy of 68%, followed by IL-18 (0.7036) with an accuracy of 66% and Gal-3 (0.6891) with an accuracy of 61%. Moreover, we then fit a stepwise multivariate logistic regression model using ASC, IL-18, and Gal-3 to determine the probability of patients having a NASH diagnosis, which resulted in an AUC of 0.71 and an accuracy of 79%, indicating that combining these biomarkers increases their diagnostic potential for NASH. These results indicate that ASC, IL-18, and Gal-3 are reliable biomarkers of NASH and that combining these analytes increases the biomarker potential of these proteins.  相似文献   
87.
Hermaphroditic invertebrates and plants have a self-recognition system on the cell surface of sperm and eggs, which prevents their self-fusion and enhances non-self-fusion, thereby contributing to genetic variation. However, the system of sperm–egg recognition in mammals is under debate. To address this issue, we explored the role of major histocompatibility complex class I (MHC class I, also known as histocompatibility 2-Kb or H2-Kb and H2-Db in mice) antigens by analyzing H2-Kb-/-H2-Db-/-β2-microglobulin (β2M)-/- triple-knockout (T-KO) male mice with full fertility. T-KO sperm exhibited an increased sperm number in the perivitelline space of wild-type (WT) eggs in vitro. Moreover, T-KO sperm showed multiple fusion with zona pellucida (ZP)-free WT eggs, implying that the ability of polyspermy block for sperm from T-KO males was weakened in WT eggs. When T-KO male mice were intercrossed with WT female mice, the percentage of females in progeny increased. We speculate that WT eggs prefer fusion with T-KO sperm, more specifically X-chromosome-bearing sperm (X sperm), suggesting the presence of preferential (non-random) fertilization in mammals, including humans.  相似文献   
88.
Calcium-doped lanthanum chromite reacted with silica to form silicates and chromium oxide at 1473-1773 K. A reaction mechanism was proposed at each temperature. At 1473 K, a reaction zone was observed in two areas: one was the bulk reaction area where silicates and chromium oxide were formed near the reaction interface; the other was the grain boundary reaction area where chromium oxide and calcium silicate spots were formed far from the reaction interface. Above 1673 K, silicates in the La2O-CaO-SiO, system and chromium oxide were formed simultaneously in the reaction zone with no grain boundary reaction. No layered reaction products were observed in the reaction zone of the lanthanum chromite side. Formation of melt silicates above 1723 K at the reaction interface resulted in strong bonding between calcium-doped lanthanum chromite and silica.  相似文献   
89.
90.
The effect of the size of the aggregate on ASR expansion has already been well illustrated. This paper presents a microscopic model to analyze the development of ASR expansion of mortars containing reactive aggregate of different sizes. The attack of the reactive silica by alkali was determined through the mass balance equation, which controls the diffusion mechanism in the aggregate and the fixation of the alkali in the ASR gels. The mechanical part of the model is based on the damage theory in order to assess the decrease of stiffness of the mortar due to cracking caused by ASR and to calculate the expansion of a Representative Elementary Volume (REV) of concrete. Parameters of the model were estimated by curve fitting the expansions of four experimental mortars. The paper shows that the decrease of expansion with the size of the aggregate and the increase of the expansion with the alkali content are reproduced by the model, which is able to predict the expansions of six other mortars containing two sizes of reactive aggregate and cast with two alkali contents.  相似文献   
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