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Search Results: 1 - 10 of 44902 matches for " TAO Jia-sheng "
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Design-in Reliability for Modern Wavelength-division Multiplex (WDM) Distributed Feedback (DFB) InP Lasers
Jia-Sheng Huang
Applied Physics Research , 2012, DOI: 10.5539/apr.v4n2p15
Abstract: Due to the increasing channel density in WDM network, the reliability requirement of each channel has become increasingly stringent. To meet the stringent WDM reliability requirement, it is necessary to achieve stable threshold current and wavelength over time. In this paper, we study the design-in reliability of DFB InP lasers involving the controlling parameters such as p-metal contact, epitaxial regrowth interface, substrate quality and laser cavity length. We will discuss the influence of each parameter and physical mechanism. We demonstrate significant reliability improvement with incorporation of design and process optimization. We also discuss the correlation of reliability degradation and wavelength drift.
Burn-In Aging Behavior and Analytical Modeling of Wavelength-Division Multiplexing Semiconductor Lasers: Is the Swift Burn-In Feasible for Long-Term Reliability Assurance?
Jia-Sheng Huang
Advances in OptoElectronics , 2013, DOI: 10.1155/2013/568945
Abstract: Effective and economical burn-in screening is important for technology development and manufacture of semiconductor lasers. We study the burn-in degradation behavior of wavelength-division multiplexing semiconductor lasers to determine the feasibility of short burn-in. The burn-in is characterized by the sublinear model and correlated with long-term reliability. 1. Introduction As the demand of data, voice, and video play grows, the bandwidth requirement for downstream and upstream transmissions continues to increase. Recently, there has been accelerated growth in bandwidth demand due to the introduction of mobile smart phones and portable touch screen tablets (iPhone, iPad, etc.). Wavelength-division multiplexing has been the enabling technology for higher bandwidth. To meet the WDM applications where a high density of channels is in service, each channel requires superior reliability and wavelength stability. Some network and cable operators have tightened up their wavelength stability from 0.1?nm to 0.03–0.09?nm [1–4]. On the other hand, there has been an ongoing driver to reduce the manufacturing cost and cycle time of the laser components. One way to achieve the lower cost is by means of qualification improvement. In this paper, we study the burn-in behavior of the WDM distributed feedback (DFB) lasers and correlate it with long-term reliability. We characterize the burn-in behavior using sublinear model and determine the burn-in times. We also correlate the burn-in with the long-term life test. We demonstrate that swift burn-in screen of BH lasers is feasible while meeting the long-term WDM reliability requirement. 2. Experimental The buried heterostructure (BH) DFB lasers with C-band (1550?nm and vicinity) lasing wavelength were used for the study. Epitaxial layers were grown on n-type InP substrate using metal organic chemical vapor deposition (MOCVD) technique. First, n-doped InP buffer layer was grown. An active layer consisting of multiquantum well structures and grating layers were grown sequentially. The composition of the active region was InGaAsP. A mesa structure was formed by wet etch. Subsequently, p-InP and n-InP burying layers were grown to form current blocking. The final regrowth layer was grown, etched into mesa structure, and covered with SiNx/SiO2 dielectric layers. The contact opening in the dielectric was created by reactive ion etching (RIE), and the p-metallization stack of Ti/Pt/Au/Cr/Au was deposited to make ohmic contact. On the n-side, the wafer was thinned by lapping and deposited with AuGe/Ni/Au to form n-contact.
Selection and Mid-infrared Spectroscopy of Ultraluminous Star-Forming Galaxies at z~2
Guanwen Fang,Jia-Sheng Huang,S. P. Willner,Xu Kong,Tao Wang,Yang Chen,Xuanbin Lin
Physics , 2014, DOI: 10.1088/0004-637X/781/2/63
Abstract: Starting from a sample of 24 \micron\ sources in the Extended Groth Strip, we use 3.6 to 8 \micron\ color criteria to select ultraluminous infrared galaxies (ULIRGs) at $z\sim2$. Spectroscopy from 20-38 \micron\ of 14 objects verifies their nature and gives their redshifts. Multi-wavelength data for these objects imply stellar masses ${>}10^{11}$ \Msun\ and star formation rates $\ge$410 \Msun yr$^{-1}$. Four objects of this sample observed at 1.6 \micron\ (rest-frame visible) with {\it HST}/WFC3 show diverse morphologies, suggesting that multiple formation processes create ULIRGs. Four of the 14 objects show signs of active galactic nuclei, but the luminosity appears to be dominated by star formation in all cases.

XU Wei,LI Chi-Tao,CAO Ding-Chen,YIN Jia-Sheng,
徐 伟

水生生物学报 , 2007,
Abstract: Scales of different color selected from several kinds of carps and crucian carps were observed by microscope.The fishes were common carp,common crucian carp,red crucian carp,transparent color crucian carp,blue carp,red purse carp and ornamental carp.According to the results obtained during the observation,the scale is composed of 4 kinds of chromatophore,namely,erythrophore,xanthophore,melanophore and guanophore,which distribute the upper and lower layer of the scale.It is the different combination,sizes and shapes of the chromatophore that constitute variable body colors.The main characteristic of the transparent color crucian carp is that basic absence of guanophore in the lower layer,whereas complete presence in other species.There is no erythrophore and xanthophore in the blue carp,with which mainly takes on a blue crystal in guanophore layer. The genesis of the body color was also observed during the fry reproduced to the body color appeared.The body color of the fry is pretty similar between common carp,common crucian carp,red crucian carp and transparent color crucian carp.The common features are of the bigger branch melanophore inside and transparent body which signal the gray color.The body colors both of the fry of the red purse carp and the ornamental carp are very close,expressing fresh yellow.Except for the eyes,the rest part of the whole body is transparent without melanophore deposition.Both fry with 25 days old of transparent color crucian carp and ornamental carp,the body color begins to differentiate remarkably,whereas,the body color of the 50 days old fry of the red crucian carp gradually turns the gray to the red.

CHEN Lin,SUI Xin-guang,TAO Jia-sheng,LI Fu-jun,

腐蚀科学与防护技术 , 2007,
Abstract: By chemical examination in laboratory and test in situ, we found that the CI^- content and SO^2-4 content are higher in Daqing oilfield, and the variation of the soil resistivity is bigger. The soils show strong corrosivity along longitudinal depth to steel equipments. By means of contact test with a reference electrode underground, we measured the distribution of casing protection potential along vertical depth. The results indicate that the casing protection potential curve is smooth, and the protection potential is lower than -850 mV. The casing protection current can polarize up to 10000 cm in depth. The bracelet anode and the casing can installed or repaired simultaneously in the fled with no additional troubles and cost to the conventional field operation, therefore, it is of applicable value.
Associated jpsi + gamma diffractive production: the nature of Pomeron and test of hard diffractive factorization
Jia-Sheng Xu,Hong-An Peng
Physics , 1998, DOI: 10.1103/PhysRevD.59.014028
Abstract: We present a study of diffractive associated jpsi + gamma production at the Fermilab Tevatron and LHC based on the Ingelman-Schlein model for hard diffractive scattering and the factorization formalism of NRQCD for quarkonia production. We find that this process (p + pbar to p + jpsi + gamma + X) can be used to probe the gluon content of the Pomeron and test the assumption of diffractive hard scattering factorization. Using the renormalized Pomeron flux factor D simeq 0.11 (0.052), the single diffractive jpsi + gamma production cross section at 4
Diffractive $J/ψ$ production through color-octet mechanism in resolved photon processes at HERA
Jia-Sheng Xu,Hong-An Peng
Physics , 1999, DOI: 10.1103/PhysRevD.60.094010
Abstract: We use the color-octet mechanism combined with the two gluon exchange model for the diffractive $J/\psi$ production in resolved photon processes. In the leading logarithmic approximation in QCD, we find that the diffractive $J/\psi$ production cross section is related to the off-diagonal gluon density of the proton, the gluon density of the photon and to the nonperturbative color-octet $^3 S_{1}^{(8)}$ matrix element of $J/\psi$. The cross section is found to be very sensitive to the gluon density of the photon. As a result, this process may provide a wide window for testing the two-gluon exchange model, studying the nature of hard diffractive factorization breaking and may be particularly useful in studying the gluon distribution of the photon. And it may also be a golden place to test the color-octet mechanism proposed by solving the $\psi'(J/\psi)$ surplus problem at the Tevatron.
Exclusive decay of $1^{- -}$ heavy quarkonium into photon and two pions
J. P. Ma,Jia-Sheng Xu
Physics , 2001, DOI: 10.1016/S0370-2693(01)00612-8
Abstract: We study the exclusive decay of $1^{--}$ heavy quarkonium into one photon and two pions in the kinematic region, where the two-pion system has a invariant mass which is much smaller than the mass of heavy quarkonium. Neglecting effects suppressed by the inverse of the heavy quark mass, the decay amplitude can be factorized, in which the nonperturbative effect related to heavy quarkonium is represented by a non-relativistic QCD matrix element, and that related to the two pions is represented by a distribution amplitude of two gluons in the isoscalar pion pair. By taking the asymptotic form for the distribution amplitude and by using chiral perturbative theory we are able to obtain numerical predictions for the decay. Numerical results show that the decay of $\jpsi$ can be observed at BEPC and at CESR. Experiment observation of this process in this kinematic region at BEPC and CESR can provide information about how gluons are converted into the two pions and may supply a unique approach to study $ I = 0$ s-wave $\pi \pi$ scattering.
Ratio of Photoproduction Rates of $\jpsi$ and $ψ(2S)$
J. P. Ma,Jia-Sheng Xu
Physics , 2002,
Abstract: There are different approaches for diffractive photoproduction of charmonia. Recently, a new approach is proposed, in which charm quarks are taken as heavy quarks and the nonperturbative effect related to charmonia can be handled with nonrelativistic QCD. The interaction between the $c\bar c$ pair and the initial hadron is through exchange of soft gluons. The exchange of soft gluons can be studied with heavy quark effective theory and an expansion in the inverse of charm quark mass $m_c$ can be employed. In this approach a simple formula for the S-matrix can be derived by neglecting higher orders in $m_c^{-1}$ and relativistic correction related to charmonia. The S-matrix is related to the usual gluon distribution $g(x)$ at small $x$. This result is different than those from other approaches. Confronting experiment the result is not in agreement with experimental measurement because large errors from higher order in $m_c^{-1}$ and from relativistic corrections. Nevertheless the ratio of cross sections of $\jpsi$ and $\psi(2S)$ can be predicted more precisely than cross-sections. In this letter we show that the ratio predicted in this approach with an estimation of relativistic corrections is in good agreement with the recent measurement at HERA.
Production of $0^{++} $glueball from double diffractive process in high energy $p+p(\bar p)$ collision
Hong-An Peng,Jia-Sheng Xu
Physics , 1997, DOI: 10.1007/s100529900961
Abstract: Motivated by the recent experimental data about candidates for glueball from different processes, we discuss in this paper the production of 0^{++} glueball from double diffractive scattering at momentum transfer |t|< 1GeV^2 in high energy p+p(\bar p) collision. We apply the phenomenology of Pomeron (IP) of Donnachie-Landshoff, the field theory model of IP of Landshoff-Nachtmann and the relevant calculating approachs. We assume while IP coupling with glueball, the 0^{++} glueball can be considered as a bound state of two non-perturbative massive gluons. We evaluate the dependence of cross section for 0^{++} glueball production on system energy $\sqrt{s}$ and show that it could be tested experimentally.
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