Laser Cooling of 85Rb Atoms to the Recoil Temperature Limit

We demonstrate the laser cooling of 85Rb atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme [Kerman et al., Phys. Rev. Lett. 84, 439 (2000)], where a fast cooling of atoms to an auxiliary state is followed by a slow cooling to a dark state. This method has the advantage of independent control of the heating rate and cooling rate from the optical pumping beam. We operate the lattice at a Lamb-Dicke parameter eta=0.45 and show the cooling of spin-polarized 85Rb atoms to the recoil temperature in both dimension within 2.4 ms with the aid of adiabatic cooling

Transporting long-lived quantum spin coherence in a photonic crystal fiber

Confining particles in hollow-core photonic crystal fibers has opened up new prospects to scale up the distance and time over which particles can be made to interact with light. However, maintaining long-lived quantum spin coherence and/or transporting it over macroscopic distances in a waveguide remain challenging. Here, we demonstrate coherent guiding of ground-state superpositions of 85Rb atoms over a centimeter range and hundreds of milliseconds inside a hollow-core photonic crystal fiber. The decoherence is mainly due to dephasing from residual differential light shift (DLS) from the optical trap and the inhomogeneity of ambient magnetic field. Our experiment establishes an important step towards a versatile platform that can lead to applications in quantum information networks and matter wave circuit for quantum sensing.Comment: Accepted by Physical Review Letter

Ultrastructural Localization of Solanidine in Potato Tubers

Solanine, the green substance in potato, Solanum tuberosum L., tubers, is a toxic glycoalkaloid that is a potential human health hazard. To control the formation of this glycoalkaloid a greater understanding of its site of synthesis is needed. Labelling of solanidine, a direct precursor in the biosynthesis of solanine, with digitonin may indirectly locate the site of solanine synthesis in tubers. A study using ultrastructural cytochemical techniques was initiated to explore this possibility. Sprouted tips and peridermal complex (periderm and cortex) tissue were fixed three different ways: (1) glutaraldehyde only, (2) osmium tetroxide and glutaraldehyde, and (3) glutaraldehyde-osmium tetroxide-digitonin mixture. The glutaraldehyde-osmium tetroxide-digitonin mixture provided the best fixation for this study and was used throughout. An alkaloid extract of potato tissues incubated with digitonin resulted in a precipitate being formed. Application of the alkaloid extract to TLC plates before and after incubating with digitonin indicated only solanidine was removed by the digitonin. In the electron micrographs the solanidine-digitonin complex was recognized as darkly stained needles or spicules. These spicules were observed mostly in the vacuoles in the sprouted tips. However, a few spicules were also noted in the cytoplasm. Relatively few spicules were observed in the peridermal tissue

The synthesis and characterization of chlorinated polyethylene-g-styrene and its application as a blend modifier.

The graft products were purified by solvent extraction followed by selective precipitation to remove the styrene homopolymer and unreacted chlorinated polyethylene. Solubility behavior of CPE and polystyrene in various solvents was studied and the solubility parameter was estimated from the solubility result. The compositions of the separated fractions were determined by infrared spectroscopy (IR) so that the degree of grafting and graft efficiency could be evaluated.The graft copolymers were melt blended with incompatible polyblends such as polyvinyl chloride-polystyrene blend and low density polyethylene-polyvinyl chloride-polystyrene blend in an attempt to improve the interface adhesion between incompatible phases. Evidences of interaction between the graft copolymer and the homopolymers were obtained from photomicrographs and dynamic mechanical results of the graft modified polyblends. Impact strength of the polyvinyl chloride-polystyrene blend increased by 48 to 75%, with the addition of CPE-g-styrene copolymers. The fact the addition of the graft copolymer reduced the domain size substantially indicates the modification effect due to graft copolymer.The graft copolymers and CPE were characterized by IR and laser-Raman spectroscopy, differential scanning calorimetry and dilute solution viscosity measurement.Chlorinated polyethylene-g-styrene copolymers have been synthesized by chemical and radiation initiation methods. With the use of a pre-initiation technique, graft efficiency as high as 0.84 has been achieved from the chemical-initiated graft copolymerization. The chemical-initiated grafting was found to be significantly affected by the degree of swelling, initiation time and temperature and concentration of initiator and monomer. High initiation temperatures or long initiation times may result in crosslinking in the CPE films. The radiation-induced grafting was carried out using a mutual-irradiation method and graft efficiency was found to be around 0.40. No crosslinking was observed with the dose level used in this study

Reserves Estimation and Economic Modelling Of Tight Gas/ Unconventional Reservoir

Reserves estimation for oil and gas reservoir has always been an interesting topic in the effort of estimating the volume of hydrocarbon in the world, which can be recoverable and economically produced. Recently, unconventional gas reservoirs have becoming hot topic of interest and playing an ever increasing role towards satisfying current and future energy demands, due to their high possibility for gas production. Therefore, this paper will discuss about the reserves estimation for tight gas/ unconventional reservoirs alongside with the economic modelling. Numerous methods of reserves estimation has been introduced decades ago to accurately estimate the hydrocarbon volumes. However, not all methods of reserves estimation is suitable for tight gas/ unconventional reservoirs. With the advances of technology, sophisticated methods or techniques are being applied to explore the hydrocarbon world in the extent that we never encounter before, especially in the context of unconventional resources. Therefore, comprehensives information regarding tight gas/ unconventional reservoirs will be discussed in this project. Ultimately, our goal in this project is to identify different methods of reserves estimation for tight gas/ unconventional reservoirs and study the best available method as well as introduce any other approach or modification made for the method of reserves estimatio