[en] The amount of dry matter produced per photosynthetically active radiation (PAR) intercepted by the canopy (EPAR) and factors which might affect EPAR were determined for various soybean cultivars, and their relationships were also analyzed in two field experiments. In 1989 and 1990, 11 cultivars and 27 cultivars respectively, were grown on an experimental field in shiga Prefectural Junior College. Changes of intercepted PAR, top dry matter weight, light extinction coefficient (KPAR), nitrogen content per leaf area (SLN) and nitrogen accumulation in the top (1990 only) were measured. EPAR averaged for all the cultivars was 2.48g MJ(-1) in both years and its coefficient of variance among cultivars was +- 9% in 1989 and +- 17% in 1990. In general, recent cultivars showed greater EPAR than older ones. The correlation coefficients between SLN and EPAR were 0.548 in 1989 and 0.651-- in 1990, while there was no correlation between KPAR and EPAR. Since SLN showed close correlation with SLW (r = 0.954 in 1989, r = 0.170-- in 1990), the difference in EPAR between old and new cultivars was considered to be attributable mainly to the improved leaf morphological trait and consequently greater leaf photosynthesis of newer cultivars. SLN further correlated with total top nitrogen content (r = 0.736-- in 1990) thus seemed to be limited by nitrogen accumulation

[en] The ability of skin epidermal cells to induce allogeneic lymphocytes into proliferation was examined in mixed skin cell-lymphocyte culture reaction (MSLR). The stimulatng capacity of skin cells was reduced significantly by trypsin digestion, although the damage was repaired by incubation at 37 C for 3 hr. The optimal concentration of mitomycin C for treatment of stimulating cells in the MSLR differed from that in mixed lymphocyte culture reaction (MLR). Irradiation rendered them three to four times more stimulatory than did mitomycin C. Removal of adherent cells from responding cells by passage through a nylon-wool column gave a substantial elevation of the MSLR. The lymphocytes cocultured with skin cells in the primary MSLR incorporated ³H-thymidine, with the peak at the 6th day of culture. If the lymphocytes primed in the MSLR were restimulated with skin cells from the same stimulating strain, the primed lymphocytes responded promptly and in great magnitude

[en] The initial growth of Si_1-x-yGe_xC_y film with Si_1-xGe_x interlayer on Si(1 0 0) surface is investigated by scanning tunneling microscopy and reflection high energy electron diffraction. The increase in the Ge fraction of Si_1-xGe_x interlayers raises the critical thickness of the transition from two-dimensional (2D) to three-dimensional (3D) growth of Si_1-x-yGe_xC_y layers, and is effective to suppress the surface-roughening of Si_1-x-yGe_xC_y layers. The atomic-scale valley structure separating 2D-islands of the Si_1-x-yGe_xC_y layers are observed on the surface, which is deduced to be the structure for the compressive-strain relaxation of Si_1-x-yGe_xC_y layers on the Si substrate as well as missing dimmer rows

[en] We have measured the conductance of Cu nanocontacts for biases V_b=0.1-0.8 V and investigated the bias dependence of the formation probability p_Cu of Cu single-atom contacts (SACs). We found that p_Cu decreases with increasing V_b and vanishes at a critical bias V_bc ∼0.7 V, contrary to V_bc ∼2.3 V for p_Au of Au SACs. Both p_Cu and p_Au, however, show the same bias dependence when plotted against the reduced bias V_b/V_bc

[en] We have investigated the relationship between strain-relaxation behaviors and dislocation structures in SiGe layers on Si(0 0 1) substrates grown by the two-step stain-relaxation procedure. From the plan-view transmission electron microscopy (TEM) observation, three kinds of dislocation structures at the SiGe/Si interface can be observed, reflecting the propagation process of 60 deg. dislocations in the SiGe layer. Threading dislocations in the strain-relaxed SiGe layer observed in the plan-view TEM image show the correspondence to pit morphologies formed on the surface detected by atomic force microscopy. In samples after the two-step growth, the degree of strain-relaxation measured by X-ray diffraction is found to be larger than that estimated from dislocation separations at the SiGe/Si interface measured from the TEM images and the [1 1 0] edge component of Burgers vector of the 60 deg. dislocation. This indicates that additional factors other than the [1 1 0] edge component of Burgers vector of the 60 deg. dislocation also play a role in relaxing the strain along the [1 1 0] direction in the SiGe buffer layer

[en] We have studied the He-Si(100) scattering potential by considering the charge densities associated with different tilted dimer model structures. We demonstrate the inadequacy of spherical charge superposition schemes and develop an alternative procedure [modified atomic charge superposition (MACS)] which is calibrated against self-consistent linear-augmented-plane-wave charge densities. We demonstrate the transferability of the underlying MACS parameters for different periodicities of tilted dimer models of the Si(100) surface. We show that tilted dimer models of the Si(100) surface are consistent with experimental He diffraction data only if they are in an alternating c(4 x 2) array

[en] Bias-induced local heating in Au atom-sized contacts (ASCs) has been studied at 4.2 K by measuring the frequency ν of the conductance two-level fluctuations (TLFs) under high biases of 0.60-0.95 V. The measured logν shows a broad single-peak distribution with the peak frequency logν_m shifting to higher values with increasing bias. The logν_m-V plot is nonlinear at 4.2 K in contrast to the linear behaviour observed at 77 K. The difference in the bias dependence of logν_m manifests a bias-induced overheating in Au ASCs at 4.2 K, which renders the effective contact temperature T_eff much higher than 4.2 K. Our experimental results suggest that T_eff ∝ √V

[en] Abstract:The abundance of radiocarbon in natural samples has been measured using the Tandetron mass spectrometer at Nagoya University. The result shows that the radiocarbon dating is possible with the precision of less than 0.5% error using the graphitized target. The error is mainly due to the statistical uncertainty deduced from total ¹⁴C count and can be reduced if more ¹⁴C count is obtainable. The ages measured for samples of less than several thousand years old are consistent with the values by the beta decay counting method. The sample preparation to provide a proper solid target and the results for testing the performance of the spectrometer are described. (author)

[en] Through performance testing of a pilot-scale melter, the authors have confirmed that certain items are especially important in applying the liquid-fed ceramic melter to commercial-scale vitrification. Pilot-scale melter was designed and fabricated based on the melter technology developed by Power Reactor and Nuclear Fuel Development Corporation (PNC). The electrode power supply data were compared from two different start-up operations using the glass cullets with and without noble metals. And the comparison showed almost no difference between main electrode resistances regardless of the presence or absence of noble metals. Sugar was added to the liquid waste feed to cause the exothermic reaction during glass formation reaction at cold cap.It increased the melting efficiency following to the addition rate. Glass-draining operations were performed, and stable and smooth glass flow was obtained

[en] High Level Liquid Waste (HLLW) is planned to be solidified to glass by vitrification process. HLLW is fed to a Liquid Fed Ceramic Melter (LFCM) with glass former and vitrified in it. In this process, a portion of ruthenium in HLLW releases from the LFCM into the off-gas system. The released ruthenium is removed in the off-gas system and the decontaminated off-gas is released from a stack into atmosphere. In this study, the ruthenium release rate from the pilot scale LFCM was evaluated based on an inactive operational data. In the results of the experiments, the release rate of ruthenium from the LFCM were about 10 % of the feed rate of it and similar to previous works. (author)