625 research outputs found

    Design Procedures for a Fully Differential Telescopic Cascode Two-Stage CMOS Operational Amplifier

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    AbstractIn this paper, a fully differential telescopic operational amplifier design is presented which achieve both high dc gain and high unity-gain frequency. Trade-offs among such factors as bandwidth, gain, phase, margin, bias current, signal swing, slew rate, and power are made evidently. The characteristic of this kind of two-stage operational amplifier is investigated theoretically, in this paper. The results indicate that proposed two-stage operational amplifier achieves broader unity bandwidth, increases the DC gain. Simulation results show that, at 5V power supply, the output swing is ±4.3V, settling time is 167.4ns. Based on the two-stage operational amplifier structure, the operational amplifier with 2.5V output common voltage shows a DC gain greater than 87dB, Gain Bandwidth over 39MHz (5pF load) and a phase margin larger than 84° with power dissipation of 3mW. These good results could be used in Σ-△ modulation and A/D conversion etc

    Lepton flavor violation decays τμP1P2\tau^-\to \mu^- P_1 P_2 in the topcolor-assisted technicolor model and the littlest Higgs model with TT parity

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    The new particles predicted by the topcolor-assisted technicolor (TC2TC2) model and the littlest Higgs model with T-parity (called LHTLHT model) can induce the lepton flavor violation (LFVLFV) couplings at tree level or one loop level, which might generate large contributions to some LFVLFV processes. Taking into account the constraints of the experimental data on the relevant free parameters, we calculate the branching ratios of the LFVLFV decay processes τμP1P2\tau^-\to\mu^- P_1 P_2 with P1P2P_1 P_2 = π+π\pi^+\pi^-, K+KK^+K^- and K0K0ˉK^0\bar{K^0} in the context of these two kinds of new physics models. We find that the TC2TC2 model and the LHTLHT model can indeed produce significant contributions to some of these LFVLFV decay processes.Comment: 24 pages, 7 figure

    Revisión sobre métodos de preparación, mecanismos y aplicaciones de péptidos antioxidantes en aceites

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    Natural antioxidants, especially those used in edible oil, are safer compared to chemically synthesized antioxidants. Therefore, research on natural antioxidants has become prevelant. Antioxidant peptides derived from food protein can effectively prevent oil oxidation. Protein hydrolyzation is widely applied for the production of antioxidant peptides in industry, and bioinformatics is employed nowadays to generate the desired peptide sequence. Furthermore, the mechanism of antioxidant peptides in the oil system is still controversial, which limits the further development of antioxidant peptides as food antioxidants. This review introduces the preparation method of antioxidant peptides and their mechanisms as well as applications in the oil. It will help to comprehensively understand the function of antioxidant peptides and promote their development in the oil field.Los antioxidantes naturales, especialmente utilizados en aceites comestibles, son más seguros en comparación con los antioxidantes sintetizados químicamente. Por lo tanto, la investigación sobre antioxidantes naturales se convierte en un punto de interés. Los péptidos antioxidantes derivados de las proteínas alimentarias pueden prevenir eficazmente la oxidación del aceite. La hidrolización de proteínas se usa ampliamente en la industria para la producción de péptidos antioxidantes y la bioinformática se emplea hoy en día para generar la secuencia de péptidos deseada. Además, el mecanismo de los péptidos antioxidantes en el sistema oleoso sigue siendo controvertido, lo que limita el desarrollo posterior de péptidos antioxidantes como antioxidantes alimentarios. Esta revisión presenta el método de preparación de péptidos antioxidantes y su mecanismo, así como las aplicaciones en aceite, lo que ayudará a comprender de manera integral la función de los péptidos antioxidantes y promoverá su desarrollo en el campo petrolero

    Search for Top Quark FCNC Couplings in Z' Models at the LHC and CLIC

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    The top quark is the heaviest particle to date discovered, with a mass close to the electroweak symmetry breaking scale. It is expected that the top quark would be sensitive to the new physics at the TeV scale. One of the most important aspects of the top quark physics can be the investigation of the possible anomalous couplings. Here, we study the top quark flavor changing neutral current (FCNC) couplings via the extra gauge boson Z' at the Large Hadron Collider (LHC) and the Compact Linear Collider (CLIC) energies. We calculate the total cross sections for the signal and the corresponding Standard Model (SM) background processes. For an FCNC mixing parameter x=0.2 and the sequential Z' mass of 1 TeV, we find the single top quark FCNC production cross sections 0.38(1.76) fb at the LHC with sqrt{s_{pp}}=7(14) TeV, respectively. For the resonance production of sequential Z' boson and decays to single top quark at the Compact Linear Collider (CLIC) energies, including the initial state radiation and beamstrahlung effects, we find the cross section 27.96(0.91) fb at sqrt{s_{e^{+}e^{-}}}=1(3) TeV, respectively. We make the analysis to investigate the parameter space (mixing-mass) through various Z' models. It is shown that the results benefit from the flavor tagging.Comment: 20 pages, 17 figures, 6 table

    First Report of Alternaria Black Spot Disease Caused by Alternaria alternata on the Invasive Weed Solanum rostratum in Xinjiang, China

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    Solanum rostratum is a noxious weed, native to Mexico and the USA, which has invaded Liaoning, Jilin, Hebei, Inner Mongolia, Shanxi, Xinjiang and Beijing, China (Eminniya et al., 2013). In August 2015, foliar symptoms of yellowish to black spots were observed on plants of S. rostratum nearby an agricultural plantation in Changji, Xinjiang. The following year, about 17% of the 206 plants surveyed on about 0.2 ha of deserted farmland were infected from July-September (at 19-35°C under 29-97% RH)

    Establishment of serum protein pattern for screening colorectal cancer using SELDI-TOF-MS

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    Aim: The purpose of this study is to develop a proteomic pattern for distinguishing individuals with colorectal cancer from healthy controls and monitoring micrometastasis using SELDI-TOF-MS. Methods: A training set consisting of 63 patients with colorectal cancer, 20 patients with benign colorectal diseases and 26 healthy volunteers was used to develop a proteomic model that discriminated colorectal cancer effectively. The sensitivity and specificity of this model was validated by an independent test set. To explore serum proteins changed after operation, the protein profiles of 31 postoperative patients were compared with those of preoperative patients. We also analyzed protein profiles of patients with and without metastasis to monitor micrometastasis. Results: Our study yielded a four-peak model (m/z: 3191.5, 3262.9, 3396.3 and 5334.4) that discriminated cancer from non-cancer samples with sensitivity of 90.3% and specificity of 95.7%. This model was validated in the test set with sensitivity of 87.5% and specificity of 93.8% which was significantly better than the combination use of CEA, CA199 and CA242 (sensitivity 62.4%) for early detection of colorectal cancer. Two peaks (m/z: 2753.8 and 4172.4) were found down-regulated in postoperative samples comparing with preoperative samples. We also detected two proteins (m/z: 9184.4 and 9340.9) that can discriminate patients with primary colorectal cancer from metastatic colorectal cancer. Conclusions: The four-peak model and two peaks (m/z: 2753.8 and 4172.4) detected in this study have the potential for assistance in diagnostics and therapeutic strategies in colorectal cancer and the two proteins (m/z: 9184.4 and 9340.9) were effective biomarkers for monitoring micrometastasis.Цель: исследование белкового профиля сыворотки крови больных колоректальным раком и здоровых доноров методом SELDI-TOF-MS для диагностики заболевания и мониторинга микрометастазов. Методы: методом SELDI-TOF-MS исследованы сыворотки крови 63 больных колоректальным раком, 20 больных с доброкачественными новообразованиями прямой кишки и 26 — здоровых доноров. Проведено сравнение профилей белков сыворотки крови 31 больного до и после хирургического вмешательства, а также больных с метастазами или без таковых. Результаты: получена 4-пиковая модель (m/z: 3191,5; 3262,9; 3396,3 и 5334,4), позволяющая отличить опухолевые образцы от неопухолевых с чувствительностью 90,3% и специфичностью 95,7%. Такая модель проверена в тест-системе с чувствительностью 87,5% и специфичностью 93,8%, что является лучшим результатом, чем комбинированное применение CEA, CA199 и CA242 (чувствительность 62,4%) для раннего выявления колоректального рака. Выявлено снижение интенсивности двух пиков (m/z: 2753,8 и 4172,4) при сравнении образцов до и после проведения операции, и идентифицированы два белка (m/z: 9184,4 и 9340,9), позволяющие выявлять больных колоректальным раком с метастазами. Выводы: полученная мо

    Partial wave analysis of J/\psi \to \gamma \phi \phi

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    Using 5.8×107J/ψ5.8 \times 10^7 J/\psi events collected in the BESII detector, the radiative decay J/ψγϕϕγK+KKS0KL0J/\psi \to \gamma \phi \phi \to \gamma K^+ K^- K^0_S K^0_L is studied. The ϕϕ\phi\phi invariant mass distribution exhibits a near-threshold enhancement that peaks around 2.24 GeV/c2c^{2}. A partial wave analysis shows that the structure is dominated by a 0+0^{-+} state (η(2225)\eta(2225)) with a mass of 2.240.02+0.030.02+0.032.24^{+0.03}_{-0.02}{}^{+0.03}_{-0.02} GeV/c2c^{2} and a width of 0.19±0.030.04+0.060.19 \pm 0.03^{+0.06}_{-0.04} GeV/c2c^{2}. The product branching fraction is: Br(J/ψγη(2225))Br(η(2225)ϕϕ)=(4.4±0.4±0.8)×104Br(J/\psi \to \gamma \eta(2225))\cdot Br(\eta(2225)\to \phi\phi) = (4.4 \pm 0.4 \pm 0.8)\times 10^{-4}.Comment: 11 pages, 4 figures. corrected proof for journa

    Measurements of the observed cross sections for e+ee^+e^-\to exclusive light hadrons containing π0π0\pi^0\pi^0 at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV

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    By analyzing the data sets of 17.3, 6.5 and 1.0 pb1^{-1} taken, respectively, at s=3.773\sqrt s= 3.773, 3.650 and 3.6648 GeV with the BES-II detector at the BEPC collider, we measure the observed cross sections for e+eπ+ππ0π0e^+e^-\to \pi^+\pi^-\pi^0\pi^0, K+Kπ0π0K^+K^-\pi^0\pi^0, 2(π+ππ0)2(\pi^+\pi^-\pi^0), K+Kπ+ππ0π0K^+K^-\pi^+\pi^-\pi^0\pi^0 and 3(π+π)π0π03(\pi^+\pi^-)\pi^0\pi^0 at the three energy points. Based on these cross sections we set the upper limits on the observed cross sections and the branching fractions for ψ(3770)\psi(3770) decay into these final states at 90% C.L..Comment: 7 pages, 2 figure

    Regulating C<sub>2</sub>H<sub>2</sub>/CO<sub>2</sub> adsorption selectivity by electronic-state manipulation of iron in metal-organic frameworks

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    The separation of C2H2 from C2H2/CO2 mixture is of great importance, yet highly challenging in the petrochemical industry due to their similar physicochemical properties. While open-metal sites (OMSs) in metal-organic frameworks (MOFs) are known to possess high affinity toward C2H2, its selective adsorption performance regulated by the electronic state of the same OMSs remains unexplored. Here, we report a metal electronic-state manipulation approach to construct a pair of isostructural Fe-MOFs, namely LIFM-26(Fe[II]/Fe[III]) and LIFM-27(Fe[III]) with different Fe[II] or Fe[III] oxidation states on the Fe centers, which display mixed-valent Fe[II]/Fe[III] centers in the former and sole Fe[III] centers in the latter. Remarkably, LIFM-26(Fe[II]/Fe[III]) shows significantly enhanced C2H2 uptake capacity than LIFM-27(Fe[III]), attested by adsorption isotherms and IAST calculations, as well as simulated and experimental breakthrough experiments. Furthermore, in situ infrared (IR) and molecular calculations unveil that the presence of Fe[II] in LIFM-26(Fe[II]/Fe[III]) results in stronger Fe[II]–C2H2 interactions than Fe[III]–C2H2, which plays a key role in the C2H2/CO2 separation
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