(5E)-2-[4,5-Bis(methyl­sulfan­yl)-1,3-dithiol-2-yl­idene]-5-(4-iodo-1,3-dithiol-2-yl­idene)-1,3-dithio­lan-4-one

The mol­ecular framework of the title compound, C11H7IOS8, is almost planar [maximum deviation = 0.040 (4) Å], except for the two methyl­sulfanyl groups, which are twisted relative to the mol­ecular skeleton, making C—S—C—C torsion angles of 144.1 (8) and −141.3 (8)°. In the crystal, mol­ecules are stacked alternately in opposite orientations, forming a one-dimensional column parallel to [110]. The primary inter­actions between mol­ecules comprising the columns are of the S⋯S type [3.554 (1) Å]. Inter­actions between columns are of the S⋯S type [3.411 (1) along b and 3.444 (1) Å along c], as well as S⋯I contacts [3.435 (2) Å]

5-(4,5-Diiodo-1,3-dithiol-2-yl­idene)-4′,5′-bis­(methyl­sulfan­yl)-2,2′-bi-1,3-dithiole-4(5H)-thione

The mol­ecular skeleton of the title mol­ecule, C11H6I2S9, is nearly planar [maximum deviation 0.052 (3) Å] except for the two methyl groups. In the crystal, mol­ecules related by translation along b axis are associated into columns through π–π inter­actions between the five-membered rings, with a centroid–centroid distance of 3.593 (5) Å. Inter­action between adjacent columns is accomplished by short S⋯I contacts of 3.2099 (4) Å

Quantum mechanically driven structural-spin glass in two dimensions at finite temperature

In magnetic materials, spins sometimes freeze into spatially disordered glassy states. Glass forming liquids or structural glasses are found very often in three dimensions. However, in two dimensions(2D) it is believed that both spin glass and structural glass can never exist at a finite temperature because they are destroyed by thermal fluctuations. Using a large-scale quantum Monte Carlo simulation, we discover a quantum-mechanically driven 2D glass phase at finite temperatures. Our platform is an Ising spin model with a quantum transverse field on a frustrated triangular lattice. How the present glass phase is formed is understood by the following three steps. First, by the interplay of geometrical frustration and quantum fluctuation, part of the spins spontaneously form an antiferromagnetic honeycomb spin-superstructure. Then, small randomness in the bond interaction works as a relevant perturbation to this superstructure and breaks it up into {\it domains}, making it a structural glass. The glassiness of the superstructure, in turn, generates an emergent random magnetic field acting on the remaining fluctuating spins and freezes them. The shape of domains thus formed depends sensitively on the quenching process, which is one of the characteristic features of glass, originating from a multi-valley free-energy landscape. The present system consists only of {\it a single} bistable Ising degree of freedom, which naturally does not become a structural glass alone nor a spin glass alone. Nevertheless, a glass having both types of nature emerges in the form of coexisting two-component glasses, algebraic structural-glass and long-range ordered spin-glass. This new concept of glass-forming mechanism opens a way to realize functional glasses even in low dimensional systems.Comment: 21pages, 14figure

Performance of the unique-word-reverse-modulation type demodulator for mobile satellite communications

This paper proposes a new type of coherent demodulator, the unique-word (UW)-reverse-modulation type demodulator, for burst signal controlled by voice operated transmitter (VOX) in mobile satellite communication channels. The demodulator has three individual circuits: a pre-detection signal combiner, a pre-detection UW detector, and a UW-reverse-modulation type demodulator. The pre-detection signal combiner combines signal sequences received by two antennas and improves bit energy-to-noise power density ratio (E(sub b)/N(sub 0)) 2.5 dB to yield 10(exp -3) average bit error rate (BER) when carrier power-to-multipath power ratio (CMR) is 15 dB. The pre-detection UW detector improves UW detection probability when the frequency offset is large. The UW-reverse-modulation type demodulator realizes a maximum pull-in frequency of 3.9 kHz, the pull-in time is 2.4 seconds and frequency error is less than 20 Hz. The performances of this demodulator are confirmed through computer simulations and its effect is clarified in real-time experiments at a bit rate of 16.8 kbps using a digital signal processor (DSP)

Theoretical study of a localized quantum spin reversal by the sequential injection of spins in a spin quantum dot

This is a theoretical study of the reversal of a localized quantum spin induced by sequential injection of spins for a spin quantum dot that has a quantum spin. The system consists of ``electrode/quantum well(QW)/dot/QW/electrode" junctions, in which the left QW has an energy level of conduction electrons with only up-spin. We consider a situation in which up-spin electrons are sequentially injected from the left electrode into the dot through the QW and an exchange interaction acts between the electrons and the localized spin. To describe the sequentially injected electrons, we propose a simple method based on approximate solutions from the time-dependent Schr$\ddot{\rm o}$dinger equation. Using this method, it is shown that the spin reversal occurs when the right QW has energy levels of conduction electrons with only down-spin. In particular, the expression of the reversal time of a localized spin is derived and the upper and lower limits of the time are clearly expressed. This expression is expected to be useful for a rough estimation of the minimum relaxation time of the localized spin to achieve the reversal. We also obtain analytic expressions for the expectation value of the localized spin and the electrical current as a function of time. In addition, we found that a system with the non-magnetic right QW exhibits spin reversal or non-reversal depending on the exchange interaction.Comment: 12 pages, 12 figures, to be published in Phys. Rev. B, typos correcte

2,5-Bis(1,3-dithiol-2-yl­idene)-1,3-dithiol­ane-4-thione

The asymmetric unit of the title compound, C9H4S7, contains two independent mol­ecules, in one of which the central five-membered ring is disordered over two orientations in a 0.924 (3):0.076 (3) ratio. The mol­ecular skeleton is almost planar: the average distance of the atoms from their mean plane is 0.128 (7) Å in the ordered mol­ecule, and 0.088 (5) and 0.123 (2) Å in the major and minor disorder components, respectively. The ordered and disordered mol­ecules form separate columns by stacking along the b axis. Adjacent columns inter­act via short S⋯S [3.33 (2), 3.434 (3), 3.444 (2), 3.503 (2), 3.519 (3) and 3.53 (4) Å] and S⋯H [2.814 (2), 2.87 (7), 2.92 (2), 2.9269 (18), 2.93 (2), 2.94 (2), 2.939 (2), 2.967 (2) and 2.974 (1) Å] contacts

海水ウラン捕集機能を有する高性能ペプチド樹脂の開発

金沢大学工学部本研究では、海水ウランに対し高吸着能を示すペプチド樹脂を実用性の高い、より高機能な樹脂に発展させるため、新規ペプチド支持体の開発とこれまで開発してきた樹脂の改良研究を試み、ウラン捕集性能に関する基礎的な評価を行った。先ず、クロロメチル及びアミノメチルポリスチレン樹脂を基体としたアミノ酸樹脂を合成し、次いで、順次鎖長を延長した各ペプチド樹脂を合成した。合成樹脂は希酸、水などで繰り返し洗浄し、樹脂精製法に改良を加えた。また、各種アミノ酸をスペ-サ-のジアミンを介してアクリル酸に結合したモノマ-を合成し、これをラジカル共重合して、親水性と耐久性に優れたポリアクリルアミド型樹脂を開発した。ペプチド樹脂は炭酸ウラニル種に対し吸着活性を示すが、酸処理した樹脂に平衝吸着量の飛躍的な向上が認められた。炭酸溶液中ではLys(424mg/g-樹脂)、β-Ala(427mg)などとなったが、この傾向は天然海水を用いた場合も認められた。また、ポリアクリルアミド型樹脂では1le(469mg)、Arg(426mg)などとなり、導入アミノ酸のほぼ化学量論的なウラン吸着を達成できた。新樹に吸着したウランに残存配位する炭酸数を求めるため吸着平衝の解析を行ったが、ジ炭酸種として取り込まれていることが明らかとなった。IR測定結果と併せ、プロトン付加した残基アミノ基がウランの捕捉に有効に働くものと推定した。更に海水マトリックス成分の影響を解析した結果、ウランの吸着速度に影響を及ぼす化学種は硫酸イオンであることがわかった。基礎実験と併行して、海水ウランの採取実験を行った。昨年度に作製した装置に、新たに海水循環恒温装置を装着し、本学能登臨海実験所に於て通水実験を行ったが、200lの海水を処理して得られた採取量はGlu(296μg/g-樹脂)、1le(180μg)、His・Gly(95μg)などであった。今後、機械的強度に優れた海水ウラン採取用樹脂としても最適化を図る予定である。研究課題/領域番号:01603518, 研究期間(年度):1989出典：研究課題「海水ウラン捕集機能を有する高性能ペプチド樹脂の開発」課題番号01603518（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-01603518/）を加工して作

耐久性アミノ酸樹脂を用いる炭酸ウラニル捕集と同位体分離濃縮に関する研究

金沢大学工学部1. 耐久性アミノ酸樹脂の合成と樹脂物性 アミノメチル化ポリスチレン樹脂を基体に,各種アミノ酸及び擬アミノ酸を活性エステル化法により導入した樹脂を15種合成した.アミノ酸導入量は2〜3.7mmol/g-樹脂であり,イオン交換容量,比重,含水率,IRなどの測定により,開発樹脂の物性を評価した.また,樹脂の酸洗浄,アルカリ浸漬,再使用性を検討し,耐久性の機能性樹脂であることを明らかにした.2.ウラン吸着容量と選択吸着機能 開発樹脂は炭酸ウラニル種に大きな吸着活性を示したが,ウラン平衡吸着量はGly,Arg樹脂で950mgU/g-樹脂以上となり,樹脂の高性能化を達成した.ウラン吸着速度は極めて速く,吸着等温式の解析によりジ炭酸種がLangmuir型吸着すると解釈された.プロトン付加したアミノ酸残基アミノ基が吸着の駆動力となると考えられるが,アミノ基に立体障害を有する擬アミノ酸の導入により,その機能を確認した.更に,炭酸濃度,海水マトリックス,移動相を用いたウランの漏出,溶離挙動を検討し,ウラン選択吸着樹脂であることを立証した.今後,繊維状吸着剤への発展が望まれる.3.ウラン同位体の分離濃縮挙動 バッチ法により,樹脂接触による天然ウランの同位体分離濃縮挙動を追跡した.α線測定により各樹脂の^U/^Uの分離係数を集積したが,高温条件(90℃)の炭酸種に明確に同位濃縮効果が発現することを見出した.また,アミド結合型より,エステル結合型樹脂の方が分離効果が大きく,樹脂内アミノ酸の酸化還元作用が濃縮加速因子となることが示唆された.ここで得た分離係数は,溶液内平衡による係数の300倍以上を示す樹脂もあった.^U/^Uの分離係数はICP-MS法により測定したが,測定誤差が大きく,全体として有意な評価は行えなかった.しかし,溶液内平衡の20倍以上を示す樹脂も見出したので,今後,効率の良い多段接触分離システムへの応用が待たれる.1. Synthesis of durable amino acid resins and the resin properties : We have synthesized 15 types of amino acid resin, introducing amino acids or imitative amino acids into polystirene resin by the active esterification method. Amino acid contents introduced were estimated to be about 2-3.7 mmol/g-resin and the resin properties were evaluated by the measurement of ion exchange capacity, water content, FT-IR and etc.. We also investigated a washing effect with acids, alkali soaking and repeated use of the resins, and clarified that the developed resins were durable and functonal ones.2. Collection capacity of uranium and the selective adsorption function : The resins showed high adsorptive activity toward carbonate species of uranium. The equilibrium adsorption amounts were more than 950mg U/g-resin in Gly and Arg resins, and the high functionalization of amino acid resin was performed. The adsorption rate was exceedingly rapid and the mechanism was interpreted to be Langmuir type adsorption of dicarbonate uranyl species by the analysis of the adsorption isotherms. The protonated amino residue may behave as a driving force for adsorptions, whose function was confirmed by the introduction of iminative amino acids possessing steric hindrance in amino group. Effect of carbonate concentration and sea water matrixes, and the behaviors of break-through and elution using mobile phase were also examined, and the developed resins were proofed to be a selective adsorbent for uranium.3. Separation and concentration behaviors for uranium isotopes : The separation behaviors of natural uranium isotopes were traced by the resin contact using batch method. The separation factor (^U/^U) of each resin was accumulated by the measurement of alpha-ray. We found clearly that the isotope concentration effect largely emerged from the contact with carbonate species at high temperature condition (90ﾟC). The effect of ester-bonding type resins developed formerly was langer than that of amido-bonding types. It suggests that the oxidation-redox action of amino acid within the resin behaves as a acceleration factor of the separation. Some factors were 300 times or more against those of the equilibria in solution. Although the factiors of ^U/^U were measured by ICP-MS method, we could not perform wholly the meaning evaluation, due to large errors at the measurements. However, we found the resins possessing the factors 20 times or more against those of the solution equilibria. Accordingly, the developed resins can be expected for the application to the contact systems with multistage separations.研究課題/領域番号:06680463, 研究期間(年度):1994 – 1995出典：研究課題「耐久性アミノ酸樹脂を用いる炭酸ウラニル捕集と同位体分離濃縮に関する研究」課題番号06680463（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/report/KAKENHI-PROJECT-06680463/066804631995kenkyu_seika_hokoku_gaiyo/）を加工して作

海水ウラン捕集機能を有するペプチド樹脂の開発

金沢大学工学部本研究では、海水ウランに対し高吸着能を示すアミノ酸樹脂を、更に高機能なペプチド樹脂に発展させるため、低次のペプチドを担持した樹脂の開発とウラン捕捉性能に関する基礎的な検討を行った。先ず、クロロメチルポリスチレン樹脂を基体としてアミノ酸樹脂を合成し、これを出発物資に、順次アミノ酸鎖長を延長したペプチド樹脂を合成した。また、アミノメチル樹脂を基体として、枝分れしたペプチドを導入したポリペプチド樹脂を開発した。樹脂1g当りのウラン平衡吸着量は20〜75mg程度であったが、炭酸溶液中では著しく増大し、Arg(200mg)、Lys(110mg)となったが、この傾向は天然海水を用いても殆ど変わらなかった。ペプチド樹脂はかなり速いウラン吸着速度を有するが、末端アミノ酸のα-アミノ基と側鎖カルボキシル基が捕捉に関与することを確認した。吸着ウランは、鉱酸を用い容易に溶解し得たが、樹脂は優れた再使用性、耐酸性を保持することが明確になった。基礎実験と併行して、簡便な海水ウラン採取装置を試作し、能登臨海実験所に於て本樹脂の実用的な評価を行った。200lの海水を処理して得られたウラン採取量は、Arg(78ug/g-樹脂)、1le(175ug)などであった。温度、処理速度を制御することにより、更に採取量が増すものと思われる。また、樹脂は海水中の主要マトリックス元素であるCa、Maを殆ど吸着しないことが判明した。ウラン吸着機構については、プロトン付加したアミン基が海水中でアンテナとなり、イオンサイズの大きな炭酸ウラニル種とイオン的相互作用を及ぼし、これが駆動力となり、側鎖官能基、ペプチド結合がウランの捕捉に有効に働くことが明らかになった。ペプチド樹脂は両性イオン交換体であり、海水マトリックス成分とウラニル種との置換反応も容易である。更に安価且つ高性能なペプチド支持体を開発すれば、海水ウランの実用的採取に到達し得るものと考える。研究課題/領域番号:63603523, 研究期間(年度):1988出典：研究課題「海水ウラン捕集機能を有するペプチド樹脂の開発」課題番号63603523（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/ja/grant/KAKENHI-PROJECT-63603523/）を加工して作