181 research outputs found
The transmissibility of vibration isolators with a nonlinear anti-symmetric damping characteristic
In the present study, the concept of the Output Frequency Response Function (OFRF), recently proposed by the authors, is applied to theoretically investigate the transmissibility of SDOF passive vibration isolators with a nonlinear anti-symmetric damping curve. The results reveal that a nonlinear anti-symmetric damping characteristic has almost no effect on the transmissibility of SDOF vibration isolators over both low and high frequency ranges where the frequencies are much lower or higher than the isolator’s resonant frequency. On the other hand, the introduction of a nonlinear anti-symmetric damping can significantly reduce the transmissibility of the vibration isolator over the resonant frequency region. The results indicate that nonlinear vibration isolators with an anti-symmetric damping characteristic have great potential to overcome the dilemma encountered in the design of passive linear vibration isolators, that is, increasing the level of damping to reduce the transmissibility at the resonance could increase the transmissibility over the range of higher frequencies. These important theoretical conclusions are then verified by simulation studies
Microscale Magnetic Field Modulation for Enhanced Capture and Distribution of Rare Circulating Tumor Cells
Immunomagnetic assay combines the powers of the magnetic separation and biomarker recognition and has been an effective tool to perform rare Circulating Tumor Cells detection. Key factors associated with immunomagnetic assay include the capture rate, which indicates the sensitivity of the system, and distributions of target cells after capture, which impact the cell integrity and other biological properties that are critical to downstream analyses. Here we present a theoretical framework and technical approach to implement a microscale magnetic immunoassay through modulating local magnetic field towards enhanced capture and distribution of rare cancer cells. Through the design of a two-dimensional micromagnet array, we characterize the magnetic field generation and quantify the impact of the micromagnets on rare cell separation. Good agreement is achieved between the theory and experiments using a human colon cancer cell line (COLO205) as the capture targets
New solutions for the color-flavor locked strangelets
Recent publications rule out the negatively charged beta equilibrium
strangelets in ordinary phase, and the color-flavor locked (CFL) strangelets
are reported to be also positively charged. This letter presents new solutions
to the system equations where CFL strangelets are slightly negatively charged.
If the ratio of the square-root bag constant to the gap parameter is smaller
than 170 MeV, the CFL strangelets are more stable than iron and the normal
unpaired strangelets. For the same parameters, however, the positively charged
CFL strangelets are more stable.Comment: 5 pages, 4 figures, Revtex4 styl
Hot air drying characteristics and nutrients of apricot armeniaca vulgaris lam pretreated with Radio Frequency(RF)
[EN] Apricot pretreated with RF and then dried with convective hot air at 65℃, 3.0m/s in this research. RF pretreatment time of 20, 30, 40 and 50min were chosen. Results showed that, there is only falling rate period during apricot hot air drying, and the drying rate of apricot is improved significantly; Herdenson and Pabis model is suitable for apricot hot air drying; retentions of flavonoids, polyphenols and Vc in dried apricot were higher than those of fresh apricot; when RF treating time was chosen 30mins, nutrients retentions of Vc, flavonoid and polyphenols were 0.9543mg/100g, 5.4089mg/100g and 7.3382mg/100g, separately.The work was financially supported by the Fundamental Research Funds for the Central Universities of China (NO. GK201503072 and GK201601007).Peng, M.; Liu, J.; Lei, Y.; Yang, X.; Wu, Z.; Huang, X. (2018). Hot air drying characteristics and nutrients of apricot armeniaca vulgaris lam pretreated with Radio Frequency(RF). En IDS 2018. 21st International Drying Symposium Proceedings. Editorial Universitat Politècnica de València. 1583-1590. https://doi.org/10.4995/IDS2018.2018.7524OCS1583159
Multiple sources of infection and potential endemic characteristics of the large outbreak of dengue in Guangdong in 2014
A large outbreak of dengue, with the most documented cases, occurred in Guangdong China in 2014. Epidemiological studies and phylogenetic analysis of the isolated dengue virus (DENV) showed this outbreak was attributed to multiple sources and caused by at least two genotypes of DENV-1 (Genotypes I and III) and two genotypes of DENV-2 (Cosmopolitan and Asian I Genotypes). A retrospective review and phylogenetic analysis of DENV isolated in Guangdong showed that DENV-1 Genotype I strains were reported continuously during 2004-2014, Genotype III strains were reported during 2009-2014 ; DENV-2 Cosmopolitan and Asian I Genotype strains were reported continuously during 2012-2014. At least 45,171 cases were reported in this outbreak, with 65.9% of the patients in the 21-55-year-old group. A trend toward a decrease in the daily newly emerged cases lagged by approximately 20 days compared with the mosquito density curve. Several epidemiological characteristics of this outbreak and the stably sustained serotypes and genotypes of DENV isolated in Guangdong suggest that Guangdong has been facing a threat of transforming from a dengue epidemic area to an endemic area. The high temperature, drenching rain, rapid urbanization, and pandemic of dengue in Southeast Asia may have contributed to this large outbreak of dengue
Screening and Molecular Analysis of Single Circulating Tumor Cells Using Micromagnet Array
Immunomagnetic assay has been developed to detect rare circulating tumor cells (CTCs), which shows clinical significance in cancer diagnosis and prognosis. The generation and fine-tuning of the magnetic field play essential roles in such assay toward effective single-cell-based analyses of target cells. However, the current assay has a limited range of field gradient, potentially leading to aggregation of cells and nanoparticles. Consequently, quenching of the fluorescence signal and mechanical damage to the cells may occur, which lower the system sensitivity and specificity. We develop a micromagnet-integrated microfluidic system for enhanced CTC detection. The ferromagnetic micromagnets, after being magnetized, generate localized magnetic field up to 8-fold stronger than that without the micromagnets, and strengthen the interactions between CTCs and the magnetic field. The system is demonstrated with four cancer cell lines with over 97% capture rate, as well as with clinical samples from breast, prostate, lung, and colorectal cancer patients. The system captures target CTCs from patient blood samples on a standard glass slide that can be examined using the fluorescence in-situ hybridization method for the single-cell profiling. All cells showed clear hybridization signals, indicating the efficacy of the compact system in providing retrievable cells for molecular studies
Direct Measurements of the Branching Fractions for and and Determinations of the Form Factors and
The absolute branching fractions for the decays and
are determined using singly
tagged sample from the data collected around 3.773 GeV with the
BES-II detector at the BEPC. In the system recoiling against the singly tagged
meson, events for and events for decays are observed. Those yield
the absolute branching fractions to be and . The
vector form factors are determined to be
and . The ratio of the two form
factors is measured to be .Comment: 6 pages, 5 figure
Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta
Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector,
the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are
measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and
(7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure
BESII Detector Simulation
A Monte Carlo program based on Geant3 has been developed for BESII detector
simulation. The organization of the program is outlined, and the digitization
procedure for simulating the response of various sub-detectors is described.
Comparisons with data show that the performance of the program is generally
satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM
- …