A system suitable for studying interactions between ⁸⁷Rb Rydberg atoms and metal surfaces has been constructed. This thesis describes the design and construction of the apparatus, and some test results. Atoms in a vapor cell magneto-optical trap are transferred to a macroscopic Ioffe-Pritchard trap, where they will be RF evaporatively cooled and loaded into a magnetic microtrap (atom chip). Confinement of cold clouds at controllable distances (5–200 μm)} from a metal surface is possible. The effects of atom-surface interactions can be studied with Rydberg atom spectroscopy. Some functionality of the apparatus has been demonstrated. Approximately 1.5×10⁷ atoms were loaded into a mirror MOT, and about 6×10⁶ atoms were optically pumped to the |F=2, m_F=2> hyperfine ground state and confined in a macroscopic Ioffe-Pritchard trap. The temperature of the cloud in the trap was 42 ± 5 μK, and the 1/e lifetime is 1–1.5 s. Forced RF evaporation has been used to measure the magnetic field at the trap minimum, but RF evaporative cooling has not yet been demonstrated.

A system suitable for studying interactions between ⁸⁷Rb Rydberg atoms and metal surfaces has been constructed. This thesis describes the design and construction of the apparatus, and some test results. Atoms in a vapor cell magneto-optical trap are transferred to a macroscopic Ioffe-Pritchard trap, where they will be RF evaporatively cooled and loaded into a magnetic microtrap (atom chip). Confinement of cold clouds at controllable distances (5–200 μm)} from a metal surface is possible. The effects of atom-surface interactions can be studied with Rydberg atom spectroscopy. Some functionality of the apparatus has been demonstrated. Approximately 1.5×10⁷ atoms were loaded into a mirror MOT, and about 6×10⁶ atoms were optically pumped to the |F=2, m_F=2> hyperfine ground state and confined in a macroscopic Ioffe-Pritchard trap. The temperature of the cloud in the trap was 42 ± 5 μK, and the 1/e lifetime is 1–1.5 s. Forced RF evaporation has been used to measure the magnetic field at the trap minimum, but RF evaporative cooling has not yet been demonstrated.

Carrier dynamics in GaAs-based photoconductive terahertz (THz) sources is investigated using Monte Carlo techniques to optimize the emitted THz transients. A self-consistent Monte Carlo-Poisson solver is developed for the spatio-temporal carrier transport properties. The screening contributions to the THz radiation associated with the Coulomb and radiation fields are obtained self-consistently by incorporating the three-dimensional Maxwell equations into the solver. In addition, the enhancement of THz emission by a large trap-enhance field (TEF) near the anode in semi-insulating (SI) photoconductors is investigated. The transport properties of the photoexcited carriers in photoconductive THz sources depend markedly on the initial spatial distribution of those carriers. Thus, considerable control of the emitted THz spectrum can be attained by judiciously choosing the optical excitation spot shape on the photoconductor, since the carrier dynamics that provide the source of the THz radiation are strongly affected by the ensuing screenings. The screening contributions due to the Coulomb and radiation parts of the electromagnetic field acting back on the carrier dynamics are distinguished. The dominant component of the screening field crosses over at an excitation aperture size with full width at half maximum (FWHM) of ~100 um for a range of reasonable excitation levels. In addition, the key mechanisms responsible for the TEF near the anode of SI photoconductors are elucidated in detail. For a given optical excitation power, an enhancement of THz radiation power can be obtained using a maximally broadened excitation aperture in the TEF area elongated along the anode due to the reduction in the Coulomb and radiation screening of the TEF.

The purpose of this research is to understand the sinking particle dynamics in the Gaoping Submarine Canyon (GPSC), the change of their geochemical character, and their causal relationship with dynamic parameters. Also this research inquires into the significance of sedimentary environment, transport process, and the influence of non-tidal actions (turbidity current) in the sedimentary environment. The field experiments including LADCP moorings, T6KP(1/10/-3/20), and T7KP (7/7-9/11) sediment traps moorings were deployed in the GPSC to collect the time-series data of sinking particle and related dynamic parameters. Parameters of discrete sediment analysis were used to build continuous time-series data by interpolation, and time series analysis applied to understand the change of physical and geochemical character and their correlation with dynamic parameters. The results showed that sinking particles of different grain-size classes confront different forces in the canyon and their grain-size distribution structures are influenced accordingly. Vertical component of the flow has more influences on coarse particles, while the along canyon flow component has more influences on fine particles. The influence of semidiurnal tide on sinking particle is not clearly resoloved, but spring tide and neap tide affect them significantly. GPSC is normally a stable deposition environment dominated by tidal currents. Particle-reactive materials vary upon with clay concentration, coarse paericles vary upon with the flow field, and the change of benthic nepheloid layer thickness during spring and neap tide cycle affects the vertical distribution of particle size-groups near the bottom of canyon. The particle in the upper (rim) and lower (near the bottom) canyon belong to different transport and dynamic regimes. The upper part was affected by upwelling and shelf processes, while the lower part was affected by tidal currents. In case of episodic event, if surge-like turbidity flows pass near the canyon floor, in the waxing phase, the sinking particle would be affected by the strong momentum of resuspension and mixing which leads to a dramatic change of geochemical character of these particles. In turbidity current event, coarse sand and silt are the major particle sizes with low clay content, suspended sediment concentration about 4.41 g / l. The fluctuation of time series analysis by HHT found a frequency between 2.1~9.8 clcle per day. In the waning phase, dynamics and geochemical character of sinking particle will gradually return to those variations in tidal dominance. In winter, most sinking particles in GPSC are the source material (particles of biological origin) coming from the off-sea with the upcanyon flow during spring tide period. In summer, most sinking particles in GPSC are the terrigenous material (higher organic matter) output from the Gaoping River during typhoons, and flowing to the South China Sea along the canyon with turbidity flow.

Oxidation filters are used to decrease particulate emissions commonly. In this study, design of a particulate trap to produce an alternative, low cost filter has been aimed. An experimental setup has been installed according to standards to carry out tests of these designed filters. Electronic measurement and control systems have been attached to this setup to increase efficiency of experiments. Two filter designs have been used in the experiments. First design consists of aluminum wire cloth. Second design is sheet metal structure, which includes three longitudinal cells. Metal chip is used as filter material. Empty filter tests have been performed firstly, and then experiments have been repeated with aluminum, iron, and copper chip addition in filter. Copper chip test results are better than other metal chip for first experiments. Afterwards, experiments have been repeated with varying copper chip amount. Suitable copper chip amount was determined based on fuel consumption rate of the engine. As a result, designed filter reduce the particulate emissions with high efficiency. Although, carbon monoxide, and carbon dioxide gaseous emissions increase with designed filter, hydro carbon emissions decrease.

Human telomerase is a ribonucleoprotein complex that adds hexameric TTAGGG repeats to the ends of chromosomes in order to prevent their shortening. Telomerase activity has been evaluated for its diagnostic and prognostic value in cancer since it is observed in most malignancies but not in most normal somatic tissues. In this study telomerase activity was examined in tumor specimens obtained from cervix, endometrium and their non-cancerous regions by an improved telomeric repeat amplification protocol (TRAP) &ndash / silver staining assay. Appearance of characteristic TRAP leader with 6 base pair increments indicate a positive result and was observed in all cancerous and some of the non-cancerous tissues. Telomerase activities of carcinoma tissues and normal counterparts were compared by densitometric analysis after PCR. Significantly higher telomerase activity was observed in cervical carcinoma samples compared to normal adjacent tissue. No significant difference was observed between endometrium carcinomas and normal endometrial tissue in terms of telomerase activity. High telomerase activity in normal endometrium restricts the use of assay for detection of carcinogenesis. However, in cervical tissues an accurate quantification of telomerase activity by TRAP &ndash / silver stain assay may be valuable as a confirmatory assay.

Electrochemical hydride generation is an alternative technique to the chemical hydride generation by NaBH4 which is widely used for atomic spectrometric determination of volatile elements such as As, Bi, Ge, Pb, Sb, Se, Sn and Te. The aim of this research has been to develop an analytical technique at the level of ng/L for determination of antimony by using a simple and inexpensive AA spectrometer and the other parts that can be built in any laboratory. Carbon rod and platinum foil were used as cathode and anode materials, respectively, for the generation of antimony hydride. Argon was used as the carrier gas. Zr coated W-coil was used for on-line preconcentration of generated hydrides. A new apparatus independent from quartz T-tube atomizer was constructed and used to contain the atom trap. Zr coated W-trap was heated to the collection temperature for trapping the analyte species generated electrochemically. For the revolatilization of the trapped species, the trap was further heated to the revolatilization temperature. Revolatilized species were transported to a flame-heated quartz tube atomizer where the analytical signal was recorded. Duringcollection and revolatilization steps hydrogen gas was introduced into the system to prevent the oxidation of atom trap. The experimental operation conditions for electrochemical hydride generation and atom trapping were optimized. 3&amp / #963 / limit of detections were found to be 0.012 ng/mL and 0.41 ng/mL with and without using trap, respectively. The trap has provided 34 fold sensitivity improvement as compared with the electrochemical hydride generation alone. The interferences of some hydride forming elements and some transition metals on electrochemical hydride generation with and without employing the trap were investigated. Analysis of standard reference material was performed to check the accuracy of the proposed method.

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Abstract The carbon and oxygen isotopes of planktonic foraminifera, faunal assemblage, and coarse fraction of trap materials were analyzed in this study. The sediment traps were deployed in two lacations. One was in the Kao-ping submarine canyon and the other was in the northern South China Sea. Variations of the individual concentrations from Kao-ping submarine canyon are small throughout the deployment interval except for the period when the Typhoon Chi-Te invaded southern Taiwan in July 2000. The results that benthic foraminifer abundances (#/g) are higher than that of planktonic foraminifera after typhoon invasion reflect the influence of particle settling by lateral transport. In addition, the major planktonic foraminifera found in canyon are Globigerinoides aequilateralis, Globigerinoides ruber, Globigerinoides sacculifer, and Neogloboquadrina dutertrei. At the same time, we also found Globigerina bulloides that usually lives in the high latitudes and cold temperature. It reveals the effect of nutrient supply along coastal region. The coarse fraction contents and foraminiferal abundances collected by the traps in the northern South China Sea are both increasing in January and March. It could be associated with the enhanced surface productivity. The planktonic foraminifera divided into two groups based on their preferrence. The G. bulloides and N. dutertrei live in cold environment while G. aequilateralis, G. ruber, G. sacculifer, and Pulleniatina obliquiloculata preferr warm areas. In this study, G. bulloides and N. dutertrei were found in January whereas G. aequilateralis, G. rubber, G. sacculifer, and P. obliquiloculata were mostly in March. The difference of carbon isotopes of planktonic foraminifera between species are distinct. Orbulina universa is the heaviest and G. ruber was the lightest. Foraminiferal d18O are depleted in October and enriched in January and March. It is suggested that sea surface temperature might be responsible for the variations of planktonic foraminiferal oxygen isotopes. Comparisons of foraminiferal d18O with the hydrographic data provide some informations. The results show that G. ruber lives in shallow water (~10m), G. sacculifer lives in 25m on average, and O. universa lives in deeper water layer (~70m) in northern South China Sea. Moreover, both the carbon isotopes and foraminiferal abundance of G. ruber show a negative correlation with the particles fluxes.

An investigation of the sympathetic cooling method for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of rf heating rates on the ion temperature, trapping parameters, and the number of ions is obtained. New rf heating mechanism affecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra of the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of the laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and the influence of the rf heating rates on the fluorescence lineshapes is also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.