High‐performance a‐Si1–xOx:H/c‐Si heterojunction solar cells realized by the a‐Si:H/a‐Si1–xOx:H stack buffer layer

We used amorphous silicon oxide (a‐Si_1–xO_x:H) and microcrystalline silicon oxide (µc‐Si_1–xO_x:H) as buffer layer and p‐type emitter layer, respectively, in n‐type silicon hetero‐junction (SHJ) solar cells. We proposed to insert a thin (2 nm) intrinsic amorphous silicon (a‐Si:H) thin film between the thin (2.5 nm) a‐Si_1–xO_x:H buffer layer and the p‐layer to form a stack buffer layer of a‐Si:H/a‐Si_1–xO_x:H. As a result, a high open‐circuit voltage (V_OC) and a high fill factor (FF) were obtained at the same time. Finally, a high efficiency of 19.0% (J_SC = 33.46 mA/cm², V_OC = 738 mV, FF = 77.0%) was achieved on a 100 μm thick polished wafer using the stack buffer layer.

     

Radiation Temperature Measurement of an Imploded X-Ray Source with a Filtered-Multi-Channel Pinhole Camera

The Plankian radiation temperature of an intense x-ray source driven by imploding spherical CH plastic shell is measured with a filtered-multi-channel pinhole camera. With all the twelve laser beams of the GEKKO-XII laser facility applied, the average radiation temperature is measured to be around 465 eV while the temperature at the core is as high as 818eV. This value is confirmed by other instruments applied.     

An Accurate Multi-level Finite Difference Scheme for 1D Diffusion Equations Derived from the Lattice Boltzmann Method

An accurate and unconditionally stable explicit finite difference scheme for 1D diffusion equations is derived from the lattice Boltzmann method with rest particles. The system of the lattice Boltzmann equations for the distribution of the number of the fictitious particles is rewritten as a four-level explicit finite difference equation for the concentration of the diffused matter with two parameters. The consistency analysis of the four-level scheme shows that the two parameters which appear in the scheme, the relaxation parameter and the amount of rest particles, can be determined such that the scheme has the truncation error of fourth order. Numerical experiments demonstrate the fourth-order rate of convergence for various combinations of model parameters.     

Synthesis of bridged nicotinates having [n](2,5)pyridinophane skeletons (n=8-14)

Synthesis of various bridged nicotinates 6 having [n](2,5)pyridinophane skeletons (n=8-14) was accomplished by the unique pyridine-formation reaction of methyl propiolate with a series of formyl-substituted (vinylimino)phosphoranes 5, which were prepared from the corresponding cycloalkanones 1 via Vilsmeier-Haack formylation giving chloro-substituted cycloalkenals 2, their thermal and photochemical transformation to formyl azirines 4, and the following ring-opening reactions with triphenylphosphine. The HPLC analysis of [11](2,5)pyridinophane derivatives, (S_p,S)-14 and (R_p,S)-14, showed that these diastereomers rapidly epimerize themselves at room temperature and that their planar-chirality was thermodynamically less stable as compared to the corresponding [11](2,5)cyclophane systems.     

Microscopic observation and in-situ Raman scattering studies on high-pressure phase transformations of Kr hydrate

Direct observations through a microscope and in-situ Raman scattering measurements of synthesized single-crystalline Kr hydrate have been performed at pressures up to 5.2 GPa and 296 K. We have observed that the initial cubic structure II (sII) of Kr hydrate successively transforms to a cubic structure I (sI), a hexagonal structure, and an orthorhombic structure (sO) called "filled ice" at 0.45, 0.75, and 1.8 GPa, respectively. The sO phase exists at least up to 5.2 GPa. In addition to these transformations, we have also found the new phase behavior at 1.0 GPa, which is most likely caused by the change of cage occupancy of host water cages by guest Kr atoms without structural change. Raman scattering measurements for observed phases have shown that the lattice vibrational peak at around 130 cm(-1) disappears in the pressure region of sI, which enables us to distinguish the sI phase from sII and sH phases.     

Analysis of DNA adducts of acetaldehyde by liquid chromatography-mass spectrometry

A highly sensitive method using liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) was developed for the analysis of DNA adducts of acetaldehyde (AA). AA, which is the primary oxidative metabolite of ethanol, is considered to possess carcinogenic activity. AA reacts with the exocyclic amino group of guanine in DNA to form N2-ethylguanine (Et-Gua) and 1,N2-propanoguanine (Pr-Gua) adducts. With the present method, such adducts were detected as the base forms from DNA chains using depurination in the pretreatment process. In our measurement with LC-ESI-MS, the limits of detection (LODs) of the Et-Gua and Pr-Gua adducts of the base forms were 3.0 x 10(-10) and 1.0 x 10(-9) M, respectively, and the LODs are about two orders of magnitude lower than those of the nucleoside forms. Calf thymus DNA samples treated with AA and NaBH3CN were analyzed by this method. Et-Gua was clearly detected and, in the absence of NaBH3CN, Pr-Gua was detected predominantly. Furthermore, the method was also applied to study whether or not these two adducts are formed in DNA of cultured HL-60 cells during exposure to AA for 24 h. Pr-Gua was clearly detected and traces of Et-Gua were also detected in the DNA of the cells. Although the sensitivity of this method is lower by at least oneorder of magnitude than the 32P-postlabeling assay, currently the most sensitive method, our method does not involve complex enzymatic reactions for the postlabeling and the use of troublesome radioactive materials. Furthermore, it enables structural identification of guanine adducts. The present method would be a useful tool for studies of Et-Gua and Pr-Gua adducts in connection with carcinogenesis.