Ring Resonator Method for Evaluation of Dielectric Property of Thin Layers in Microwave Region

Teranishi, T.,Tajima, K.,Harigai, T.,Nam, S.-M.,Kakemoto, H.,Wada, S.,Tsurumi, T. MATERIALS RESEARCH SOCIETY OF JAPAN 2006 TRANSACTIONS- MATERIALS RESEARCH SOCIETY OF JAPAN Vol.31 No.1

Comparison of In vivo and In vitro Techniques for Methane Production from Ruminant Diets

Bhatta, Raghavendra,Tajima, K.,Takusari, N.,Higuchi, K.,Enishi, O.,Kurihara, M. Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.7

This study was conducted to compare the methane ($CH_4$) production estimated by in vivo (sulfur hexafluoride tracer technique ($SF_6$)) with that of two in vitro rumen simulation (RUSITEC) and gas production (IVGPT)) techniques. Four adult dry Holstein cows, aged $7.4{\pm}3.0$ years and weighing $697{\pm}70$ kg, were used for measuring methane production from five diets by the $SF_6$ technique. The experimental diets were alfalfa hay ($D_1$), corn silage + soybean meal (SBM) (910: 90, $D_2$), Italian rye grass hay +SBM (920: 80, $D_3$), rice straw +SBM (910: 90, $D_4$) and Sudan grass hay +SBM (920: 80, $D_5$). Each diet was individually fed to all 4 cows and 5 feeding studies of 17 d each were conducted to measure the methane production. In the RUSITEC, methane production was measured from triplicate vessels for each diet .In vitro gas production was measured for each of the diets in triplicate syringes. The gas produced after 24 and 48 h was recorded and gas samples were collected in vacuum vials and the methane production was calculated after correction for standard temperature and pressure (STP). Compared to the $SF_6$ technique, estimates of methane production using the RUSITEC were lower for all diets. Methane production estimated from 24 h in vitro gas production was higher (p<0.001) on $D_1$ as compared to that measured by $SF_6$, whereas on $D_2$ to $D_5$ it was lower. Compared to $SF_6$, methane production estimated from 48 h in vitro gas production was higher on all diets. However, methane estimated from the mean of the two measurement intervals (24+48 h/2) in IVGPT was very close to that of $SF_6$ (correlation 0.98), except on $D_1$. The results of our study confirmed that IVGPT is reflective of in vivo conditions, so that it could be used to generate a database on methane production potential of various ruminant diets and to examine strategies to modify methane emissions by ruminants.

Influence of Temperature and pH on Fermentation Pattern and Methane Production in the Rumen Simulating Fermenter (RUSITEC)

Bhatta, R.,Tajima, K.,Kurihara, M. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.3

An experiment was conducted to study the effect of temperature and pH on in vitro nutrient degradability, volatile fatty acid profile and methane production. The fermenter used was the semi-continuous system, known as the rumen simulation technique (RUSITEC). Sixteen cylinders were used at one time with a volume of 800 ml, the dilution rate was set at 3.5%/hour, the infused buffer being McDougall's artificial saliva. Basal diet (9.6 g DM) used in RUSITEC consisted of (DM) 6.40 g Timothy hay, 1.86 g crushed corn and 1.34 g soybean meal. The food for the fermentation vessel was provided in nylon bags, which were gently agitated in the liquid phase. The experiment lasted for 17 d with all the samples taken during the last 5 d. Treatments were allocated at random to four vessels each and were (1) two temperature levels of $39^{\circ}C$ and $41^{\circ}C$ (2) two pH levels of 6.0 and 7.0. The total diet contained ($g\;kg^{-1}$ DM) 957 OM, 115 CP and $167MJ\;kg^{-1}$ (DM) GE. Although increase in temperature from $39^{\circ}C$ to $41^{\circ}C$ reduced degradation of major nutrients in vitro, it was non-significant. Interaction effect of temperature with pH also reflected a similar trend. However, pH showed a significant (p<0.05) negative effect on the degradability of all the nutrients in vitro. Altering the in vitro pH from 7 to 6 caused marked reduction in DMD from 60.2 to 41.8, CPD from 76.3 to 55.3 and GED from 55.3 to 35.1, respectively. Low pH (6) depressed total VFA production (61.9 vs. 34.9 mM) as well as acetate to propionate ratio in vitro (from 2.0 to 1.5) when compared to pH 7. Compared to pH 7, total gas production decreased from 1,841 ml to 1,148 ml at pH 6, $CO_2$ and $CH_4$ production also reduced from 639 to 260 ml and 138 to 45 ml, respectively. This study supported the premise that pH is one of the principal factors affecting the microbial production of volatile fatty acids and gas. Regulating the ruminal pH to increase bacterial activity may be one of the methods to optimize VFA production, reduce methane and, possibly, improve animal performance.

Intramolecular olefin metathesis as a robust tool to synthesize single-chain nanoparticles in a size-controlled manner

Watanabe, K.,Tanaka, R.,Takada, K.,Kim, M. J.,Lee, J. S.,Tajima, K.,Isono, T.,Satoh, T. Royal Society of Chemistry 2016 Polymer chemistry Vol.7 No.29

<P>A comprehensive examination of the synthesis of single-chain nanoparticles (SCNPs) from statistical copolymers of n-butyl methacrylate (BMA) and 3-butenyl methacrylate (3BMA), i.e., P(BMA-co-3BMA)s, via the intramolecular olefin metathesis reaction under high dilution conditions is described. The olefin metathesis reaction of P(BMA-co-3BMA) using Grubbs' 2nd generation catalyst in CH2Cl2 efficiently gave the corresponding SCNPs under mild conditions. We achieved the size-controlled synthesis of the SCNPs by adjusting the following factors: (1) the olefin content in the precursor, (2) the molecular weight of the precursor, and (3) the solvent quality of the reaction medium. The hydrodynamic radius and the intrinsic viscosity of the resultant SCNPs were investigated by DLS and viscometric measurements, respectively, which provided further evidence of SCNP formation with controlled diameters. Furthermore, the above-established intramolecular olefin metathesis approach was successfully applied to poly(acrylate), poly(styrene), and poly(ester) precursors, which proved that the present approach could be applied to a wide range of olefin-containing precursors to give SCNPs with various functional groups.</P>

Note: Sub-Kelvin refrigeration with dry-coolers on a rotating system

Oguri, S.,Ishitsuka, H.,Choi, J.,Kawai, M.,Tajima, O. American Institute of Physics 2014 Review of scientific instruments Vol.85 No.8

<P>We developed a cryogenic system on a rotating table that achieves sub-Kelvin conditions. The cryogenic system consists of a helium sorption cooler and a pulse tube cooler in a cryostat mounted on a rotating table. Two rotary-joint connectors for electricity and helium gas circulation enable the coolers to be operated and maintained with ease. We performed cool-down tests under a condition of continuous rotation at 20 rpm. We obtained a temperature of 0.23 K with a holding time of more than 24 h, thus complying with catalog specifications. We monitored the system's performance for four weeks; two weeks with and without rotation. A few-percent difference in conditions was observed between these two states. Most applications can tolerate such a slight difference. The technology developed is useful for various scientific applications requiring sub-Kelvin conditions on rotating platforms.</P>

Magneto-Optical Properties of ZnMnSe-ZnSe-ZnCdSe Quantum Structures

T. Kato and T. Matsumoto,M. Ito,M. Tajima,K. Omori,T. Muranaka,Y. Nabetani,T. Matsumoto 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

We have studied the circularly polarized photoluminescence (PL) and reflectance properties of a series of ZnSe/ZnCdSe/ZnSe/ZnMnSe single quantum wells (SQWs) and ZnSe/ZnCdSe/ ZnSe/ZnCdMnSe /ZnSe coupled double quantum wells (DQWs). The degree of circular polarization of the exciton luminescence from the ZnCdSe non-magnetic semiconductor (NMS) well was studied as a function of the spacer layer thickness and the exciton energies in the NMS and the diluted magnetic semiconductor (DMS) regions. The polarization degree became larger as the spacer thickness became smaller. The polarization also depended on the excito n energies in the NMS and the DMS regions and became larger as the exciton energy in the nCdSe well became closer to that in the DMS layer or the DMS well.