Hitachiite, Pb5Bi2Te2S6, is a new mineral discovered in the Hitachi mine, located in the Ibaraki Prefecture of Japan. The mean of 21 electron microprobe analyses gave: Pb 52.01, Bi 23.06, Fe 0.69, Sb 0.17, Te 13.74, S 9.71, Se 0.54, total 100.04 wt.%. The empirical chemical formula based on 15 apfu is (Pb4.75Fe0.23)Σ4.98(Bi2.09Sb0.03)Σ2.12Te2.04(S5.73Se0.13)Σ5.86, ideally Pb5Bi2Te2S6. Synchrotron single-crystal X-ray diffraction experiments indicated that hitachiite has trigonal symmetry, space group P${\bar 3}$m1, with a = 4.2200(13) Å, c = 27.02(4) Å and Z = 1. The four strongest diffraction peaks shown in the powder X-ray pattern [d, Å (I)(hkl)] are: 3.541(35)(012), 3.391(59)(013), 3.039(100)(015) and 2.114(56)(110). The calculated density (Dcalc) for the empirical chemical formula is 7.54 g/cm3.

The crystal structure of hitachiite has been refined using synchrotron single-crystal X-ray diffraction data, to R = 7.38% and is based on ABC-type stacking of 15 layers (five Pb, two Bi, two Te, and six S layers) along the [001] direction, and with each layer ideally containing only one kind of atom. The stacking sequence is described as Te–Bi–S–Pb–S–Pb–S–Pb–S–Pb–S–Pb–S–Bi–Te. The discovery of hitachiite implies that the minerals of the Bi2Te2S–PbS join might form a homologous series of Bi2Te2S·nPbS.

Polymer electrolyte fuel cells hold great potential for stationary and mobile applications due to high power density and low operating temperature. However, the structural changes during electrochemical reactions are not well understood. In this article, we detail the development of the sample holder equipped with gas injectors and electric conductors and its application to a membrane electrode assembly of a polymer electrolyte fuel cell. Hydrogen and oxygen gases were simultaneously sprayed on the surfaces of the anode and cathode catalysts of the membrane electrode assembly sample, respectively, and observation of the structural changes in the catalysts were simultaneously carried out along with measurement of the generated voltages.

A novel and fundamental method was reported to judge states of lithium ion batteries (LIBs) using the capacitance and the voltage of the cells that were estimated from the real-time currents and voltage characteristics of the cells. We measured the differential capacitance, that is, dQ/dV or delta Q/ delta V that is equal to the currents (I) divided by differential voltages (dV/dt) calculated from the current and the voltage characteristics of the cell during the charging/ discharging, where Q is the charge that flows through the cell, V is the voltage of the cell and t is time. It is thought that the capacitance decrease with the degradation of the cell because the effective area of the electrodes is decreasing due to formation of undesirable compounds. The differential capacitance in some specific voltage range for the LIBs was approximately directly proportional to the state of the degradation of the cell. Therefore, it is concluded that the novel method is very useful to judge the state of the LIBs.

We review the results of very early phase optical follow-up observations of recent gamma-ray bursts (GRBs) with the multi-color optical telescopes “MITSuME”. The MITSuME telescopes were designed to perform “real time” and “automatic” follow-up observations prompted by the GCN alerts via the Internet. The rapidly slewing equatorial mounts allow MITSuME to start photometric observations within 100 seconds after the trigger for several GRBs. In particular, we detected a brightening just after the trigger for two GRBs. These phenomena could be interpreted as the “on-set” of afterglow. In this paper we summarize these optical observations with a brief interpretation.

Fractional moments of the passage-times are considered for positively recurrent Markov chains with countable state spaces. A criterion of the finiteness of the fractional moments is obtained in terms of the convergence rate of the transition probability to the stationary distribution. As an application it is proved that the passage time of a direct product process of Markov chains has the same order of the fractional moments as that of the single Markov chain.