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To evaluate the deposition density and extent of subsurface infiltration of (129)I and (137)Cs in the restricted area that was highly contaminated by the accident of Fukushima Dai-ichi Nuclear Power Plant, cumulative inventories of (129)I and (137)Cs, concentrations of (129)I and (137)Cs, and (129)I/(137)Cs ratio in 30-cm-long soil columns were compared with pre-accident levels from the same area. The cores were collected before and after the accident from locations of S-1 (4 km west of FDNPP) and S-2 (8 km west of FDNPP). Deposition densities of (129)I and (137)Cs in the soil following the accident were 0.90-2.33 Bq m(-2) and 0.80-4.04 MBq m(-2), respectively, which were 14-39 and 320-510 times larger than the pre-accident levels of (129)I (59.3-63.3 mBq m(-2)) and (137)Cs (2.51-7.88 kBq m(-2)), respectively. Approximately 90% of accident-derived (129)I and (137)Cs deposited in the 30-cm soil cores was concentrated in the surface layer from 0 to 44-95 kg m(-2) of mass depth (0-4.3-6.2 cm depth) and from 0 to 16-25 kg m(-2) of mass depth (0-1.0-3.1 cm depth), respectively. The relaxation mass depths (h0) of 10.8-11.2 kg m(-2) for (129)I estimated in the previous study were larger than those of 8.1-10.6 kg m(-2) for (137)Cs at both sites, owing to the larger infiltration depth of radioiodine mainly by the gravitational water penetration in the surface soil in our study sites. Approximately 7-9% of the accident-derived (129)I was present in the lower layer from 44 to 100 kg m(-2) (4.3-8.6 cm depth) at S-1, and from 95 to 160 kg m(-2) (6.2-10.2 cm depth) at S-2. Approximately 1% of (137)Cs seems to infiltrate deeper than (129)I in the lower layer at each site in contrast to the surface layer.

The deposition density and extent of subsurface infiltration of 129I were investigated within the area highly contaminated by the March 2011 accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in Japan. Depth profiles of 129I activity and 129I/127I ratios were measured in 5-cm-long soil cores that were collected 20–27 months after the accident from three sites (S-1, S-2, and S-3) within 10 km to the west and northwest of the FDNPP. These profiles were compared with the background levels of 129I from the same areas. The deposition densities of 129I were 2.17 Bq m−2 at S-1, 0.80 Bq m−2 at S-2, and 1.41 Bq m−2 at S-3, which are, respectively, about 160, 60, and 100 times larger than the background level (12.8–14.8 mBq m−2). The average 129I/127I ratios in each soil core after the accident (S-1: 2.1 × 10−6; S-2: 4.2 × 10−7; S-3: 2.3 × 10−6) were similar to the value typically found in contaminated surface soil within 80 km of the FDNPP. Therefore, accident-derived 129I deposited at S-1 (4.3 km west of the FDNPP) was 2.7 times larger than at S-2 (8.2 km west of the FDNPP), and 1.5 times larger than at S-3 (7.5 km northwest of the FDNPP). Depth profiles showed that the 129I activity and 129I/127I ratios decayed exponentially with depth. ∼90% of accident-derived 129I deposited in the soil cores was concentrated in the upper 25.2–26.4 kg m−2 of mass depth (2.1–3.1 cm depth). The relaxation mass depths (h0) of 129I were 9.49–11.2 kg m−2 at the three sampling sites, and these values are comparable to those of accident-derived 131I (10.4 kg m−2) at a site 40 km northwest of the FDNPP.

We have investigated vertical distributions of 110mAg, 131I, 129mTe, and 137Cs and existence in beach soil collected three months after the Great East Japan Earthquake. All the nuclides passed through tsunami deposit and original beach soil, then reached fine particle layer lying beneath them in the three months. Moreover, depth profiles of all the nuclides did not exhibit exponential decrease. Behavior of 131I, 129mTe, and 137Cs were explained with distribution coefficients (Kd) but that of 110mAg was not explained. Particulate form was observed for the 137Cs; number of the particle was proportional to the 137Cs concentration in the soil sample.

Discussed here are real-valued signal analysis and wireless baseband transmission, a system for transmitting baseband signals directly from an antenna, and transmission characteristics under a multipath environment. The field of wireless transmission generally handles band signals in which information rides on a carrier wave, and therefore signal analysis is not the direct analysis of real high-frequency signals (real-valued signals) and is performed with a system expressed using complex numbers, called an equivalent baseband system. However, wireless baseband transmission is based on a transmission system which does not use carrier waves and cannot be handled with an equivalent baseband system. Consequently, it is necessary to have a system of real-valued signal analysis for handling baseband signals, which are real-valued signals, without additional processing. The BER (bit error rate) was used as the standard for evaluating transmission characteristics under a multipath environment of wireless baseband transmission using measured channel characteristics with that algorithm. With a computer, the BER characteristics were found by varying the reflection coefficient, number of delay symbols, the ratio of direct wave power and reflected wave power, and the number of reflected waves. As a result, it was clear that the dominant factor in a multipath environment is the ratio of direct wave power and reflected wave power. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(10): 9–22, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20347

The cooling water for the electromagnetic horns is exposed to intense high-energy protons, neutrons and charged pions at the J-PARC neutrino experimental facility. These high-energy particles produce various radionuclides in the cooling water; dominant radionuclides were H and Be, and various -emitting nuclides were also detected by a Ge detector. Specific activities of individual nuclides in the circulating cooling-water were determined and compared with the results obtained by Monte Carlo calculations. The results demonstrated that H and Be were directly produced in water by nuclear spallation of oxygen in water molecules, and that other nuclides were produced in metal components and transferred into water, in accordance with the observations at other high-energy accelerator facilities.

The radiological feature of the radioactive material leak incident at the J-PARC Hadron experimental facility has been investigated. From the systematic analysis focusing on the species and behavior of radionuclides originated in the gold target that had been used for nuclear and particle physics experiments since December 14, 2012, we have figured out the major process that resulted in the release of radioactive materials into the user working areas in the Hadron experimental hall as follows; 1) a variety of radionuclides had been produced in the gold target via nuclear spallation reactions, 2) radionuclides with boiling points lower than the melting points of gold were mainly discharged from the gold target because of the instantaneous overheat which raised the temperature of the gold target above the melting point of gold by injection of the anomalously intense-pulsed beam, 3) the radionuclides diffused in the primary beam line room by the air circulation system and leaked into the user working area through the inadequate hermetic sealing for cables and bulk shields between the primary beam line room and the user working areas.

A tremendous amount of radioactivity was discharged because of the damage to cooling systems of nuclear reactors in the Fukushima No. 1 nuclear power plant in March 2011. Fukushima and its adjacent prefectures were contaminated with fission products from the accident. Here, we show a geographical distribution of radioactive iodine, tellurium, and cesium in the surface soils of central-east Japan as determined by gamma-ray spectrometry. Especially in Fukushima prefecture, contaminated area spreads around Iitate and Naka-Dori for all the radionuclides we measured. Distributions of the radionuclides were affected by the physical state of each nuclide as well as geographical features. Considering meteorological conditions, it is concluded that the radioactive material transported on March 15 was the major contributor to contamination in Fukushima prefecture, whereas the radioactive material transported on March 21 was the major source in Ibaraki, Tochigi, Saitama, and Chiba prefectures and in Tokyo.

This paper investigates multiple input multiple output (MIMO) communication systems using wireless baseband transmission (WBT) scheme which directly transmits a baseband signal stream from an antenna without modulation techniques over an extremely wideband channel. Following to the previous paper discussing the fundamental idea and the feasibility of WBT experimentally, this paper deals with WBT MIMO systems. Some natures of WBT MIMO systems and the data transmission scheme are discussed theoretically, and two types of signal processing structure, i.e., a spatio-temporal beamformer with and without the cascade connection of a one-dimensional (1-D) FIR filter are proposed for the equalization of WBT MIMO channel. Transmission characteristics in the frequency-domain are obtained through a measurement in a radio anechoic chamber, and computer simulations are carried out using them. The results show the good performance towards equalization of a WBT MIMO channel.

The aim of this study was to assess the prognostic factors of peripheral T-cell lymphoma, unspecified (PTCL-U).We retrospectively analyzed 30 cases fulfilling the criteria of PTCL-U defined by the World Health Organization classification. The patients were treated with 6-8 cycles of a CHOP or THP (pirarubicin)-COP regimen.A high serum sIL-2R level (or =2,000 U/ml) at onset was associated with a low complete remission rate. Patients with high sIL-2R had significantly lower survival rates (5 year, 15.1%) than those with low sIL-2R (2,000 U/ml) (100%) (P0.005). Factors associated with worse overall survival in a univariate analysis were high sIL-2R (P0.005), high age (60 years) (P0.05), poor performance status (P0.01) and poor international prognostic index (P0.05). No correlation was observed between sIL-2R and other markers. Multivariate analysis showed that only sIL-2R was a prognostic factor for overall survival (P0.01).The results suggest that a high serum sIL-2R level predicts a poor prognosis in PTCL-U.

Wireless Baseband Transmission (WBT) という新しい無線伝送方式を提案し，実験によってその基礎的特性を調べている．一般に伝送システムは，送りたい情報をそのまま何らかの物理的信号に対応付けて送信するベースバンド伝送方式と，搬送波と呼ばれる信号を送りたい情報によって変調して送信する搬送伝送方式の2 つに分けることができる．これまで無線伝送の分野においては搬送伝送方式のみが用いられてきた．それに対し，有線伝送においてはベースバンド伝送，搬送伝送共に利用されている．本研究は無線でもベースバンド伝送が可能かどうかを検討したものであるということができる．実験をおこなった結果，適切なアンテナ（本研究ではディスコーンアンテナ）と伝送路符号化（本研究ではManchester 符号化）を用いればベースバンド伝送を無線でおこなうことも可能であることが明らかになった．本論文は1 章から8 章までの構成である．1 章ではこれまでの無線伝送について歴史を踏まえて記述している．2 章ではWBT の概念についてWBT と比較的似ているシステムであるImpulse Radio との比較も含めて述べている．3 章ではBER（bit error rate）を計算するための実信号解析法について述べている．実信号解析法は，WBT では一般の無線伝送で用いられている等価低域系による複素領域での表現はできずに，全て実信号として取り扱う必要があることを述べたものであり，従来の無線伝送の解析と異なる点である．4 章ではWBT の時間領域における伝送実験と周波数領域での測定（100MHz）と3 章の手法を組み合わせた解析，5 章では周波数領域における測定（1 GHz）と3 章の手法を組み合わせた解析について述べている．実験は全て本学の電波暗室内でおこない，自由空間と人工的に作り出したマルチパス環境下について伝送特性の評価をおこなっている．その評価の指標としてBERを用いている．また，チャネルの周波数特性やインパルス応答についても示している．さらに，時間領域と周波数領域での測定が一致することも示している．5 章では3 章と4 章の結果を利用し周波数領域でのみ測定をおこなっている．一般に時間領域測定に比べ周波数領域測定は高い周波数まで対応可能であり，これは小型アンテナの使用ができることを意味する．測定の容易さと効率を考えると周波数領域でのみ測定しても時間領域測定と同じ結果が得られることは有益な結果であるといえる．6 章では4 章と5 章で得られた結果を基にして，送受信に無指向性アンテナを用いた場合におけるWBTの簡単な伝送モデルである-6 dB/octave モデルを示している．このモデルを使用して仮想的なアンテナ帯域幅の下限周波数，上限周波数，比帯域を変化させてBER 特性を求めている．この結果は実際のWBT 無線システムを実現するにあたり必要となる情報伝送レートとアンテナ帯域幅との関係について有意な情報を与える．また，チャネルの等化についてもふれ，さらに各種直流平衡符号に対するBER 特性の比較もおこなっている．7 章ではWBT の応用について述べている．具体的にはWBT 無線機の構成，近傍界通信への適用，さらにMIMO(multiple input multiple output) やSDR(software defined radio) といった近年無線通信の世界で話題になっているシステムについてWBT の関わりを述べている．8 章では結論を述べている．すなわち，WBT という新たな伝送方式を提案し，有線のみならず無線でもベースバンド伝送は可能であることを実験によって明らかにしたことを記述している．, 2006