Spectroscopic Studies of Surface Chemistry on Cerium Oxide

Fundamental studies of three C1 molecules (CO, CO2, and CH3OH/CD3OD) adsorption on surfaces of ceria single crystals and/or nanocrystals have been carried out by using ultra-high vacuum Fourier transform infrared spectroscopy (UHV-FTIRS) or near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The oxidation states of cerium cations were determined by the core-level and valence band X-ray photoelectron spectroscopy (XPS)

Bounced Model of Droplet on Moving Substrate

Firstly, we get the completely bouncing criteria Cr for droplet on moving substrate. The bouncing without splashing condition is $\mathrm{Cr}>1$. Then, we mainly research the effect of wind field for droplet, and get the completely bouncing criteria $\mathrm{Cr}_{\mathrm{wind}}$ for droplet with wind. Lastly, we get the contact angle of droplet on the moving substrate and calculate the Time Independent Reynolds Equation with $rho$ and $\mu$ are constant.Comment: 15 pages,3 figure

Umbrella-shaped gate field-effect transistor for biosensing measurements

Based on previous CMOS-compatible biosensor designs and the flash memory technology, a novel Umbrella-Shaped Field-Effect Transistor (UGFET) is realized as a biochemical charge sensor in the MOSIS AMIS 1.5 um standard CMOS process. The devices show high scalability and versatility needed for VLSI application. The UGFET device architecture is modified from previous CvMOS (Shen et al. 2003) and CMFET (Barbaro et al. 2006) designs and is scaled down to maximize the charge sensing area and drastically improve the chip density. The device simulation results show an approximate 1 volt increase in floating gate voltage for every 10 nC/cm^2 charge density increase on the sensing electrode. The designed UGFET devices are quite stable and very sensitive to the gate potential change. Two methods based on shifts in the threshold voltage and drifts in the subthreshold voltage slope are developed to sense and detect miniscule charges in charged poly electrolytes and poly amino acids. All the measured results are consistent and show the applicability of using UGFET devices as charge-modulated biosensors. Array implemented sensor chips are also taped out and tested with biochemical solutions

Polarization effects in the nonlinear interference of down-converted photons

We study polarization effects in the nonlinear interference of photons generated via frequency non-degenerate spontaneous parametric down conversion. Signal and idler photons generated in the visible and infrared (IR) range, are split in different arms of a nonlinear Michelson interferometer. The interference pattern for signal photons is detected, and it is shown to be dependent on the polarization rotation of idler photons, introduced by a birefringent sample. Based on this concept, we realize two new methods for measurement of sample retardation in the IR range by using well-developed and inexpensive components for visible light. The accuracy of the methods meets current industry standards. The developed IR polarimetry technique is relevant to material research, optical inspection, and quality control.Comment: Submitted for publicatio

Measurement of infrared optical constants with visible photons

We demonstrate a new scheme of infrared spectroscopy with visible light sources and detectors. The technique relies on the nonlinear interference of correlated photons, produced via spontaneous parametric down conversion in a nonlinear crystal. Visible and infrared photons are split into two paths and the infrared photons interact with the sample under study. The photons are reflected back to the crystal, resembling a conventional Michelson interferometer. Interference of the visible photons is observed and it is dependent on the phases of all three interacting photons: pump, visible and infrared. The transmission coefficient and the refractive index of the sample in the infrared range can be inferred from the interference pattern of visible photons. The method does not require the use of potentially expensive and inefficient infrared detectors and sources, it can be applied to a broad variety of samples, and it does not require a priori knowledge of sample properties in the visible range

The compositional simulation and seismic monitoring of CO2 EOR and sequestration in new gas condensate reservoir

While mature oil reservoir and aquifers are good candidates for CO2 sequestration, we proposed and investigated the alternative approach which, at the very start of production, combines CO2 sequestration and CO2 EOR in gas condensate reservoir. Firstly, we conducted compositional reservoir simulation and synthetic seismic simulation in a five-spot well pattern to investigate whether seismic data can monitor of CO2 front and gas condensate bank. The simulated results and the seismic simulation results are compared with each other. Although the density contrast among reservoir gas, injected CO2 and condensate is smaller than the density contrast in the case of CO2 sequestration in aquifer, the seismic signal can capture this smaller difference and monitor the CO2 injection front and locate the condensate zone. When there is no adequate data available for reservoir characterization at early period of production, this direct measurement is very valuable for reservoir characterization and for any stimulation of condensate block. Secondly, we compare the production by natural depletion and production combined CO2 EOR and storage at the very beginning. The latter will speed up the recovery process, increase the recovery rate while simultaneously store CO2 in reservoir. The extra benefit in gas condensate reservoir is that injection of CO2 will increase the pressure and postpone and decrease liquid dropout and relieve the condensate blocking