Reversing the Weak Quantum Measurement for a Photonic Qubit

We demonstrate the conditional reversal of a weak (partial-collapse) quantum measurement on a photonic qubit. The weak quantum measurement causes a nonunitary transformation of a qubit which is subsequently reversed to the original state after a successful reversing operation. Both the weak measurement and the reversal operation are implemented linear optically. The state recovery fidelity, determined by quantum process tomography, is shown to be over 94% for partial-collapse strength up to 0.9. We also experimentally study information gain due to the weak measurement and discuss the role of the reversing operation as an information erasure

Near-Complete Teleportation of a Superposed Coherent State

The four Bell-type entangled coherent states, |\alpha>|-\alpha> \pm |-\alpha> |\alpha> and |\alpha>|\alpha> \pm |-\alpha> |-\alpha>, can be discriminated with a high probability using only linear optical means, as long as |\alpha| is not too small. Based on this observation, we propose a simple scheme to almost completely teleport a superposed coherent state. The nonunitary transformation, that is required to complete the teleportation, can be achieved by embedding the receiver's field state in a larger Hilbert space consisting of the field and a single atom and performing a unitary transformation on this Hilbert space.Comment: 4 pages,3 figures, Two columns, LaTex2

Engineering Non-Precious Group Metal Electrode for PEMFCs with Enhanced Mass Transport via Electrospraying Technique

Ever since the concept of “Hydrogen Economy” emerged, fuel cell technology has been regarded as the key component of the clean, sustainable energy future. Thanks to great successes in the development of fuel cell technology in recent years, they are now transitioning from R&D stage to the commercial stage. Some of the major automotive companies such as Toyota and Honda have already commercialized the fuel cell vehicles. Recently fuel cell technology has emerged as an appealing technology in heavy-duty automotive industry due to its high-power output, fast fuel charge, long driving range and light weight. Currently, most commercialized fuel cell stacks either use Pt/C or Pt-alloy catalysts which makes up as much as 40% of the stack production cost. It is clear that for further market penetration the stack cost needs to be reduced by using less or no platinum. Recent advances in non-Precious Group Metal (non-PGM) catalysts have provided hopes to completely remove the expensive Pt from the stack. There has been great progress in the development of non-PGM catalysts, but they are still less catalytically active than Pt, and to compensate for low catalytic activity, higher catalyst loading is required resulting in much thicker electrodes. Thicker electrodes suffer from increased transport resistances, so careful design of the electrode is required to further improve the performance of the non-PGM materials. This thesis aims to address this issue by providing insights on how to engineer the non-PGM electrode. The work was carried out in three stages. First, the optimal composition of the non-PGM cathode was investigated using a single-phase, non-isothermal model. A comprehensive parametric study of catalyst loading, Nafion™ loading and thickness was carried out under realistic fuel cell operating conditions. This study revealed that the optimum catalyst loading was about 3.0-4.0 mg\/cm^2 whereas 70% Nafion™ was found to be the optimum. In the second stage, due to lack of available tool to characterize the mass transport characteristics of thin porous materials, such as the catalyst layers, a novel method was developed which requires no gasket making it appealing to thin catalyst layers. The method was thoroughly validated with open air and some of the traditional porous media. In the final stage, the non-PGM catalyst layers were fabricated, and their structural properties were analyzed. Properties such as pore size distribution, specific surface area and porosity were determined as well as the tortuosity using the novel method developed herein. Generally, electrosprayed non-PGM catalyst layers showed vastly improved mass transport characteristics owing to high porosity as well as increased average pore size. An empirical tortuosity-porosity relationship was also derived for electrosprayed non-PGM catalysts which would be valuable in the future modeling studies

Initiation of embryogenic callus from mature zygotic embryos in Japanese larch (Larix kaempferi)

Abstract Embryogenic callus (EC) was created from mature embryos of Larix kaempferi. With the mature embryos, keeping the culture in dark conditions throughout the experiment (38.2%) seemed to give better results than exposing them to 16 h light (25 μEm ) for the first week (21.9%). EC was obtained most frequently from Quoirin and Lepoivre (LP) mediums with 1.0 mg/L 4-amino-3,5,6-trichloropicolinic acid (Picloram), plus 1.0 mg/L benzyladenine (BA) (62.8%) or Litvay's medium (LM) containing 1.0 mg/L p-chlorophenoxyacetic acid (pCPA) plus 1.0 mg/L BA (62.8%) treatment. In both cases, best results were obtained when zygotic embryos were cultured in darkness. As for the effective sucrose concentration on initiation of EC, 29.2 mM sucrose (38.6%) gave the best results