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Two- and four-terminal photovoltaic (PV)–thermoelectric (TE) hybrid tandems are studied theoretically based on the scaling of coupled nonlinear equations for heat and electrical currents. We generally prove the equivalence between achievable output powers by two- and four-terminal tandems. If the PV and TE segments are adjusted in terms of numbers, areas, and connections in a four-terminal tandem, lossless matching is always possible in current or voltage for series or parallel two-terminal tandems while maintaining other designs, materials, or installation environments. That is, the same output power is always achievable in two- and four-terminal tandems using such adjustments.

Heat-recovery (HERC) solar cell is a concept of solar cell that converges heat into electricity and enables silicon solar cell to have high efficiency exceeding the Shockley-Queisser limit without requiring fast carrier extraction. In this paper, we show by numerical simulation its robustness against strong non-radiative recombination of the carriers and a positive effect arising from the bandgap reduction in the energy filtering layers.

Using heat that otherwise would be lost is important for efficient use of solar energy, but continues to be held back for lack of an ultrathin photovoltaic absorber that permits both sufficient absorption of light and ultrafast extraction of ``hot'' carriers before they lose their kinetic energy. This article presents a concept to enable heat recovery in a solar cell $w\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}h\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}u\phantom{\rule{0}{0ex}}t$ the need for ultrafast carrier extraction. This thermoelectric approach should impact engineering solutions for further improvement in silicon solar cells, beyond the Shockley-Queisser limit.

We demonstrate trapped exciton-polariton emission at room temperature from nonpolar GaN/AlGaN cavities sandwiched between air/AlGaN distributed Bragg reflectors. Nanoscale thickness fluctuations characteristic to the nonpolar AlGaN cavity layer create deep potential traps, giving rise to a strong (in-plane) localization of exciton-polaritons. The observed quantized exciton-polariton states exhibit a large quantized energy of up to 6 meV, which benefits from the wide bandgap of III-nitrides. The experimental results are well explained by numerical simulations. III-Nitride exciton-polaritons in such deep traps will be useful for practical exciton-polariton lasers with high degrees of coherence and high-repetition rate Josephson oscillators with multicomponent condensates.

We propose a new concept of a solar cell that enables heat recovery to improve its conversion efficiency, namely “heat recovery (HERC) solar cell”. The two key elements are an absorber hotter than electrodes and carrier-energy selecting potential barriers placed between the absorber and electrodes, whose bandgap is larger than that of the absorber. HERC solar cell operating out of equilibrium can have high efficiency exceeding the detailed-balance limit. Unlike hot carrier solar cells, it does not require fast carrier extraction within the thermalization time, which largely improves the feasibility. HERC solar cell can be realized with a silicon absorber.

The ideal solar cell conversion efficiency limit known as the Shockley-Queisser (SQ) limit, which is based on a detailed balance between absorption and radiation, has long been a target for solar cell researchers. While the theory for this limit uses several assumptions, the requirements in real devices have not been discussed fully. Given the current situation in which research-level cell efficiencies are approaching the SQ limit, a quantitative argument with regard to these requirements is worthwhile in terms of understanding of the remaining loss mechanisms in current devices and the device characteristics of solar cells that are operating outside the detailed balance conditions. Here we examine two basic assumptions: (1) that the photo-generated carriers lose their kinetic energy via phonon emission in a moment (fast thermalization), and (2) that the photo-generated carriers are extracted into carrier reservoirs in a moment (fast extraction). Using a model that accounts for the carrier relaxation and extraction dynamics, we reformulate the nonequilibrium theory for solar cells in a manner that covers both the equilibrium and nonequilibrium regimes. Using a simple planar solar cell as an example, we address the parameter regime in terms of the carrier extraction time and then consider where the conventional SQ theory applies and what could happen outside the applicable range., Comment: 25 pages, 15 figures

We propose a method to generate path-entangled NOON-state photons from quantum dots and coupled nanocavities. In the systems we considered, cavity mode frequencies are tuned close to the biexciton two-photon resonance. Under appropriate conditions, the system can have the target NOON state in the energy eigenstate, as a consequence of destructive quantum interference. The NOON state can be generated by a resonant laser excitation. This method, first introduced for a two-photon NOON state ($N=2$), can be extended toward a higher NOON state ($Ng2$) based on our recipe, which is applied to the case of $N=4$ as an example.

In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates-sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity-have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics.

In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates -- sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity -- have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband whereas many remain elusive. Understanding the observation will lead to a development in non-equilibrium many-body physics., 18 pages, 5 figures + 23 pages, 9 figures

Semiclassical equations for microcavity semiconductor lasers based on Maxwell-semiconductor-Bloch equations are solved for on-lasing state (nonequilibrium steady state) with a steady state condition for eigenfrequencies. Results for a single mode operation can account for input-output curves for laser operation, gain saturation accompanied by the spectral hole-burning in the carrier distribution, and the shift of laser frequency. We found nonmonotonic dependency of the laser frequency on the pump intensity (excited carrier density) when the cavity mode is close to the exciton level. Effects of Coulomb interaction, and phase-space filling are also discussed with reference to the case of homogeneously and inhomogeneously broadened two-level atom lasers. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

A simple calculation method for photon statistics of frequency-filtered fields is proposed. This method, based on eigenvalue decompositions of superoperators, allows us to study effects on the photon statistics of spectral filtering by various types of filters, such as Gaussian and rectangular filters as well as Lorentzian filters, which is not possible by conventional approaches. As an example, this method is applied to a simulation of quantum dot single-photon emitters, where we found the efficient choice of the filter types to have pure single photons depends on the excitation conditions i.e. incoherent or coherent (and resonant) excitations., Comment: 9 pages, 5 figures

Historical development of manufacturing technology of viscose rayon fibers at Stages IV, V and VI, defined in the previous paper (This journal, 20, 1 (2005)), was studied. In particular, since Stage V was the time of social turbulent the study was made in close connection with social background. As supplement to the previous paper, details (causes and cut-off rate) of the operational curtailments with a golden age sandwiched between them in Stage III was surveyed. Conversion of autonomic control system (Stage III) to governmental compulsory control system (Stage IV) was studied on the basis of acts, royal ordinances, ministerial ordinances and notices. The first～fifth order national plans of reduction of production and the corresponding Asahi's achievements were examined. Numerous difficulties, such as shortage of resources, energy, and man-power, encountered by Japanese rayon producers in Stage IV (1938～1945) were investigated. Technological advance (if any) in Stage IV was studied: R & D activity of Asahi men (in comparison with that in Stage III), some key technology developments continued from Stage III, and Toramomen. The route of invention and commercialization of Tramomen at Asahi in Stage IV and at Tachikawa Research Institute in Stage V and evolution of Toramomen were surveyed. New concept of high-wet-modulus rayon (Toramomen, Polynosic rayon) and the worldwide evaluation of Toramomen (polynosic) were disclosed in detail. History of some restoration plans, approved by GHQ, in Stage V (1946～1951) was surveyed together with Asahi's restoration work. During Stage VI (1952～1956) the USA's technology, directly licensed to Japanese machinery manufactures, was introduced to Japanese viscose rayon producers. Characteristics of the technology at Stage VI were discussed.

First, whole history of Japanese viscose rayon industry was divided into eight stages: Stage I (embryo), Stage II (introduction), Stage III (un-aided development), Stage IV (mid-war ordeal), Stage V (post-war reconstruction), Stage VI (post-war expansion), Stage VII (long-term recession) and Stage VII (reformation). In the previous studies the technological advance at Stage II was studied comprehensively. In this article, study on the development of manufacturing technology in Japanese viscose rayon industry at Stage III (1930～1938) was attempted in systematic manner.

An atempt was made to evaluate the unperturbed chain dimensions A of polyacrylonitrile with a wide range of stereoregularity, and of copolymers of acrylonitrile (AN) and methacrylonitrile (MA) or vinylidene chloride (VDC). For this purpose, the fraction, separated from four PAN samples with meso-meso triad content mm=26, 51, 71 and 75% and together with those of copolymers from AN/MA (AN weight % ; 92) and AN/VDC (AN weight % :59) were utilized. The light scattering and viscosity data obtained for the above fractions were analyzed by the methods 2A～2G, proposed previously.

An attempt was made to investigate apre-history of emergence of chemical fiber industry. Socially widely prevailed tendency in late 19th century to produce high-value products by modifying chemically the naturally-occurred materials, which had been exclusively employed for low-value commodity, formed a strong incentive to invent new artificial materials such as cellulose nitrate. Existing industries were activated remarkably by replacing the natural materials with cellulose nitrate, which was then applied to bear new industries. Chemical fiber industry was a typical example. Numerous trials to produce artificial fiber from other materials than natural silk were historically surveyed mainly on the patent specifications. All the inventions, except Swan's, prior to Chardonnet's, were of 'Imagination Age'. Artificial thread was first produced temporarily on a small scale for electric incandescent lamp by carbonizing cellulose nitrate (to obtain carbon conductor). Electric lamp industry was a precursor of artificial industry. Five essential steps were noticed to be fulfilled concurrently to produce artificial silk for cloth or textiles. It was shown that all essential steps each had been invented, even though being far from perfection, separately by others than Chardonnet prior to Chardonnet's invention, which was commercialized on large scale for clothing. Chardonnet's process was consisted of cellulose nitrate, collodion, dry (or wet) spinning and after-treatment (denitration). In this sense, there was no significant originality in the principle of his process. However, Chardonnet's technology, judged from his patent specifications, was outstandingly precise and accurate enough to enable any one of average engineers or chemists to reproduce Chardonnet's invention by following the specification alone. Then, his patent specifications are equivalent or sometimes superior to contemporary scientific and technical papers. Chardonnet was the first, who used the term 'artificial silk' for the fibers spun from collodion. Chardonnet was also the first person, who applied his inventions internationally, and was the most productive: He had obtained 44 patents, which can be classified into 15 categories, ranging from 1884 to 1923 over almost 40 years (until one year before his death). These inventions had been commercialized worldwide by himself with financial help of investors. His predecessors each applied only single patent, which was not commercialized, to one country. Chardonnet studied at first in laboratory, then established a bench plant, which he operated for several years to accumulate know-how before commercialization. His development procedure is technologically very reasonable and now widely adopted in industry. Chardonnet's process evolved continuously even after commercialization.

In 1921 Asahi Kenshoku (AKS) had introduced a viscose rayon techonology from a German leading company, Vereinigte Glanzstoff A. G. (VGF), forming a first world-scale Japan-foreign joint venture with BGF (20% share holder of the capital) and establighing a plant under guidance of VGF. Afterwards, AKS catched up Europe technology. In this article an attempt was made to clarify the prcess of catch-up.

An attempt was made to uncover and investigate, from meticulous analysis on the data base of scientific papers, reviews and patents constructed in the previous paper (This journal, vol. 17, (2002)), R & D achievements of 25 ex-Asahi chemist individuals, before and during work at and after resignation from Asahi. Total number of the publications amounted to 26, 60 and 154, corresponding to the above three periods. Average duration of the employment by other organizations before joining to Asahi was 3.7 years. Judging from previous job career and R & D achievements, 3 experienced graduate chemists, 3 mid-career technical college graduates and 13 new recruitments joined to Asahi in 1919～1927. Five individuals, all of them belonging to the categories of the established and mid-career engineers, published totally 12 papers, 7 reviews (Code no. 1) and 5 patents (Code no. 6) before joining to Asahi. Ex-Asahi engineers, who resigned from Asahi before full retirement (defined as Group I), stayed on average 6 years at Asahi. All Asahi engineers, who were once employed by Asahi, published 16 papers and 44 patents at Asahi. Close correlation was confirmed among them between the productivity of scientific research and that of technological development. Research activity of some major chemists was investigated in connection with their job positions. Role of Asahi chemists was demonstrated in the three cases to vary significantly, depending on the time of resignation from Asahi.

An attempt was made to construct the most reliable database on stereoregular polyacrylonitrile (PAN) solutions for further analysis. For this purpose, literature data, reported for these 25 years by Kamicle and his coworkers at Asahi, on light scattering and limiting viscosity number [η] of PAN with various tacticity (meso-meso triad content of 26-75%) dissolved in solvents including aq. nitric acid with concentration 51-80% were utilized. The molecular weight dependences of [η]([η] = K_mM_w^a; M_w: weight-average molecular weight) and of the radius of gyration _z^ = (_z^ = K_γM_ω^γ) wene evaluated for each polymer solutions. Flory's theta solvent compositions were determined experimentally as the solution, in which the second virial coefficient A_2 vanishes a = γ = 0.5 holds in Flory solvents. The unperturbed chain dimension A and Flory viscosity parameter φ_0 were directly determined at Flory condition.

An attempt was made to survey the research and development activity of Asahi engineers before, during work at and after employment at Asahi Jinzo Kenshi (AJK) and its successor Asahi Kenshoku (ASK), which introduced a total system of German technology of viscose rayon in the form of the first joint venture with Vereinigte Glanzatoff Fabriken A. G in Japan, in 1920-1940s. For this purpose the thorough publication lists including scientific papers, reviews, books and patents were constructed exhaustively for twenty two + three Asahi engineers, using Complete Abstracts Japanese Chemical Literature and Japanese Patent Publications.

Electrons, holes, and photons in semiconductors are interacting fermions and bosons. In this system, a variety of ordered coherent phases can be formed through the spontaneous phase symmetry breaking because of their interactions. The Bose-Einstein condensation (BEC) of excitons and polaritons is one of such coherent phases, which can potentially crossover into the Bardeen-Cooper-Schrieffer (BCS) type ordered phase at high densities under quasi-equilibrium conditions, known as the BCS-BEC crossover. In contrast, one can find the semiconductor laser, superfluorescence (SF), and superradiance as relevant phenomena under nonequilibrium conditions. In this paper, we present a comprehensive generating functional theory that yields nonequilibrium Green's functions in a rigorous way. The theory gives us a starting point to discuss these phases in a unified view with a diagrammatic technique. Comprehensible time-dependent equations are derived within the Hartree-Fock approximation, which generalize the Maxwell-Semiconductor-Bloch equations under the relaxation time approximation. With the help of this formalism, we clarify the relationship among these cooperative phenomena and we show theoretically that the Fermi-edge SF is directly connected to the e-h BCS phase. We also discuss the emission spectra as well as the gain-absorption spectra., 45 pages, 21 figures; nearly identical to the published version

Incoherent pumping in quantum dots (QDs) can create a biexciton state through two paths: via the formation of bright or dark exciton states. The latter, dark-pumping, path is shown to enhance the probability of two-photon simultaneous emission, and hence increase $g^{(2)}(0)$ by a factor $\propto 1/\gamma_S$, due to the slow spin relaxation rate $\gamma_S$ in QDs. The existence of the dark path is shown to impose a limitation on the single photon (SP) emission process, especially in nanocavities which exhibit a large exciton-cavity coupling and a Purcell enhancement for fast quantum telecommunications., Comment: 12 pages, 6 figures

The separation of a gas from a two component gas system was studied both theoretically and experimentally. Helium and argon as an inorganic gas pair, ethylene and butane as an organic gas pair, and air were used. The theory based on the free molecular flow could not be applied to all the combinations of the gases experimentally studied. Experiments showed that the permeability coefficient of each component in the mixture was very close to that of each single component, when the pressure in the low pressure side became zero, but those of the mixture approached one another rapidly as the pressure increased. In the case of the separation of one inorganic gas from another, there exists most suitable pressures both in the high and low pressure sides for the most efficient separation, as considered from the selectivity and permeability. In the cases of the mixed organic gases and the organic-inorganic gas combination, a rather high separation efficiency is expected for a very high pressure on the high pressure side.

The coexistence curve of well-characterized polydisperse polystyrene in cyclohexane (${\mathrm{M}}_{\mathrm{w}}$ =23.9\ifmmode\times\else\texttimes\fi{}${10}^{4}$ , ${\mathrm{M}}_{\mathrm{w}}$ /${\mathrm{M}}_{\mathrm{n}}$ =2.8) was measured near the critical point, where ${\mathrm{M}}_{\mathrm{w}}$ and ${\mathrm{M}}_{\mathrm{n}}$ are weight- and number-average molecular weights, respectively. The shape of the coexistence curve was expressed by the critical exponent ${\mathrm{\ensuremath{\mathrm{B}}}}_{\mathrm{t}}$ =0.363\ifmmode\pm\else\textpm\fi{}0.005, which agrees with the exponent of Fisher's renormalization for the Ising system with hidden variables.

An attempt was made (1) to prepare porous regenerated cellulose membranes by casting cellulose cuprammonium solutions and then immersing them into aqueous acetone solutions as coagulant, and (2) to investigate membrane characteristics such as radius of secondary particles S 2 on the surfaces of the membranes, mean pore diameter measured by the water-flow-rate method 2r f , membrane porosity by apparent density method Pr(d 3 ), and membrane thickness of dry membrane L d , and (3) to clarify phenomenological effects of solvent-casting conditions on pore characteristics of the membrane formed and to explain the effect in terms of the particle growth theory proposed previously by Kamide Iijima et al. (KI). Surfaces of membranes prepared by immersing cast solutions in coagulation solution having weight fraction of acetone w Acetone below 0.30 consisted of the secondary particles of polymer-rich phase (referred to as polymer particle). As the ammonia concentration in the system was higher, polymer particles of polymer-rich phase grow faster; ammonia was one of the most important factors dominating the size of polymer particles, composing the membranes. L d was in proportion to the cellulose weight fraction w cell of cast solutions; on the contrary, Pr(d 3 ) and 2r f were inversely proportional to w cell . These experimental findings suggest strongly that density of dried polymer particles increases in proportion to w cell in the solutions. Pore shape in a whole body of a membrane changed drastically from noncircular pores to circular pores when w Acetone in coagulation solutions exceeded 0.30, indicating that w Acetone dominates phase separation conditions such as phase volume ratio R(?V (1) V (2) V (1) and V (2) are volumes of polymer-lean and -rich phases. respectively), compositions of phase separation points. Changes in Pr(d 3 ). 2r, and tensile strength TS of the membranes, prepared by using coagulation solutions having different w Acetone coincide fairly well with that of pore shape. Membranes constructed by larger cellulose particles have larger pores, and this tendency agreed well with results obtained by Kl's lattice theory on pore size distribution proposed before.

We investigate spin-charge mixing effect on the resonant tunneling in a spin-polarized Tomonaga–Luttinger liquid, which arises from Fermi velocity differences between two spin species due to Zeeman effect. Zero bias conductance is calculated as a function of gate voltage V g , gate magnetic field B g , temperature and magnetic field applied to the system. Mixing effect is found to cause deformations of contour shapes of the conductance in ( V g , B g ) plane. At low temperatures, contour shapes are divided into three types; the conductance peaks (1) vanish, (2) form lattices, and (3) form lines. Each corresponds to the phase impurity potential become (1) irrelevant for two spins, (2) relevant for two spins, and (3) relevant for one selective spin.

Coupled QED cavity arrays are shown to exhibit first-order phase transitions between superfluid and Mott-insulator or different superfluid states in presence of two photon modes. This indicates the system is applicable to quantum optical switching devices.

A new lasing showing a unique spectrum based on a highly excited exciton-polariton condensate is implemented. Observed high energy peak matches a theory describing nonequilibrium system.

We clarify the nonequilibrium phase diagram in cavity QED arrays under incoherent pumping and loss. In coherent phase, plateau regions of the photon frequency appear. In incoherent phase, the excitation number takes non-integer discrete values.

We theoretically investigated the ground states of coupled arrays of cavity quantum electrodynamical (cavity QED) systems in presence of two photon modes. Within the Gutzwiller-type variational approach, we found the first-order quantum phase transition between Mott insulating and superfluid phases as well as the conventional second-order one. The first-order phase transition was found only for specific types of emitter models, and its physical origin is clarified based on the analytic arguments which are allowed in the perturbative and semiclassical limits. The first-order transition of the correlated photons is accompanied with discontinuous change in the emitter states, not only with the appearance of inter-cavity coherence in the superfluid phase. We also discuss the condition for the first-order transition to occur, which can lead to a strategy for future design of quantum optical switching devices with cavity QED arrays., Comment: 11 pages, 11 figures (corrected typos, added references, added discussions in section 2, results unchanged.)

The mechanism of second thresholds observed in several experiments is theoretically revealed by studying the BEC-BCS-laser crossover in exciton-polariton systems. We found that there are two different types for the second thresholds; one is a crossover within quasi-equilibrium phases and the other is into non-equilibrium (lasing). In both cases, the light-induced band renormalization causes gaps in the conduction and valence bands, which indicates the exsistence of bound electron-hole pairs in contrast to earlier expectations. We also show that these two types can be distinguished by the gain spectra., Comment: 10pages, 4figures. Accepted in Physical Review Letters. Several typing errors are corrected

Characterization of Anisotropic Mesophase of Cellulose Acetate in Inorganic Solvent Mixture

An attempt was made (1) to correlate permeation properties such as filtration rate, filtration coefficient, and critical filtration volume with filtration conditions of virus contaminated aqueous solutions through porous regenerated cellulose membrane, (2) to demonstrate possibility of complete rejection of viruses from filtrate, (3) to clarify the captured state of viruses in the membrane and the concentration distribution of the captured viruses to the direction of thickness of the membrane, and (4) to propose the mechanism of capturing viruses with the membrane by taking into account the membrane structure and a three-dimensional form of pores (i.e., morphology of pores). Porous regenerated cellulose membrane prepared by the phase separation method consisted of the secondary particles of cellulose, and there exist large cavities and narrow veins connecting these cavities in the membrane. Most of virus particles were trapped either in veins by the blocking or in cavities by the accumulation, but a very few of them flowed downstream and finally contaminated in filtrate. A “critical filtration volume Vc [ml cm−2]” was defined as total filtration volume obtained till the moment when the first virus reached to the opposite (i.e., rear) side of the membrane. Complete rejection of viruses from the filtrate was achieved until total filtration volume reached Vc, which increased with the pressure difference ΔP and concentration of virus in the filtrand c0. Without exceeding its Vc, the porous cellulose membrane will be one of possible membranes designed for the removal of virus from aqueous serum protein mixtures.

An attempt was made to decide the most stable structure for isotactic polyacrylonitrile using dimer and trimer model compounds with aids of semi-empirical quantum chemical methods (i.e., CNDO/2 and MINDO/3 methods) where possible conformations were considered by rotating main chain bond and bending nitrile triple bond from ordinary C-C-N straight bond at side chain. The results show that two adjacent nitrile groups have mutual attractive interactions and bend to get near to each other by assuming the prolonged CN bond length which reflects the tendency of double bond for CN groups in meso arrangement. This conclusion supports Kamide et al.’s proposal deduced from the systematic experimental results on chain stiffness and NMR peak assignment for stereoregular polyacrylonitrile. The bending nitrile bond structure of PAN was obtained for the first time from the view point of molecular orbital interactions in low molecular model compound.

ナイロン66繊維の放置過程における超分子構造, 特に結晶および無定型領域内部の分子鎖の凝集構造の経時変化について検討した.ナイロン66繊維は室内および室外に約1000日放置した.その間の超分子構造の変化は広角X線回折, 干渉顕微鏡, 動的粘弾性によって評価した.その結果, 放置時間の経過に伴ってナイロン66繊維の結晶領域においては, 結晶は大きくなり, その完全度も高くなる.また配向度は小さくなる.無定型領域においては, 放置時間の経過に伴って, 分子鎖はいったん緊張状態になり, その後緩和する.さらに900日を経過すると分子鎖の充?状態の密な部分が新たに出現する.これらの変化は室外放置試料において著しい.

An attempt was made to calculate, by the Monte Carlo method, monomer sequence length distributions of the hard segment (MSLDH) within a linear segmented poly(urethane-urea) (PUR) synthesised by the prepolymer method in which an isocyanate-terminated prepolymer, A...A, an unreacted monomer diisocyanate, BB, and a diamine as chain extender, XY, are reacted to form PUR. MSLDH is governed by the molar ratio of [A...A]/[BB] and is dramatically affected when three kinds of unequal reactivity associated with the reactants are significant simultaneously ; the induced asymmetry, the penultimate effect of an NCO group, and the induced asymmetry of an amino group. By applying the above simulation technique, the unequal reactivities are estimated in both the prepolymerisation and polymerisation reactions based on methylenebis(4-phenylisocyanate), MDI, poly(tetramethyleneoxide), PTMO, and ethylenediamine, EDA. In addition, the effect of the one-shot method instead of the prepolymer method on MSLDH is also examined.

An attempt was made to determine, by the chromatographic method, monomer sequence length distributions of the hard segments in segmented poly(urethane-urea)s (PURs) synthesised in a two-step process : (1) a prepolymer formation reaction of an excess of methylenebis(4-phenylisocyanate) (MDI) with poly(tetramethyleneoxide) (PTMO) and (2) a polymerisation reaction of the prepolymer containing unreacted MDI with ethylenediamine, giving PUR. The monomer sequence length of the hard segment was found to become longer and its distribution to broaden as the initial concentration ratio of MDI to PTMO increased. This result is attributable to an increase of the concentration ratio of the unreacted MDI to the prepolymer, leading to gelation of the polymer solution. By comparing the chromatographic results with the theoretical data calculated in the simple case of the equal reactivity of the reactants in the prepolymerisation and polymerisation reactions, respectively, the existence of unequal reactivities of the reactants in both reactions is predicted.

On the basis of the particle growth concept proposed to explain polymeric membrane formation process by the phase separation method, an attempt was made (1) ) to establish a computer simulation method for constructing a three-dimensional multi-layered structure model of a membrane consisting of polymer particles, (2) to disclose a three-dimensional shape of through-pores, and (3) to establish relations between a probability of distributing a vacant particles in a site Pr* (i.e., porosity of a membrane) and existing probabilities of three kinds of pores such as through-, semi-open, and isolated pores, i.e., P v P s, and P v respectively. In the simulation, number ratio of hypothetical vacant particles of polymer-lean phase to polymer particles of polymer-rich phase is predetermined by an apparent two-phase volume ratio R A (= V (1)A /V (2)A , where V (1)A and V( 2 ) A are apparent volumes of polymer-lean and -rich phases in the membrane, respectively), which is estimated from an overall porosity of a membrane Pr. Particles are assumed for convenience to have the same radius of S 2 and are arranged randomly on a hypothetical hexagonally close-packed lattice plane by Monte Carlo method. From study on the effects of number of layers of the model I and size of the layer s on relations between Pr* and P v P s , and P v we concluded that it was enough for a three-dimensional model to have 20 layers, of which size is taken as 40 sites by 40 lines. Relations between Pr* and the existing probabilities P v P s , and P i constructed by the previous theory [S. Manabe, H. lijima, and K. Kamide, Polym. J., 20, 307 (1988)] and those by the present simulation are compared and it is concluded that the previous approximate theory underestimates P t (especially in the range of Pr* of 0.3 to 0.8) and P i (especially at lower Pr*) significantly.

Structure and morphology of the cellulose films coagulated from novel cellulose/9 wt% aqueous (aq.) sodium hydroxide (NaOH) systems (polymer concentration CP≤5.6 wt%) by using aq. sulfuric acid (H2SO4) with various concentration (Csa=20—80 wt%) as coagulants were investigated. For this purpose two types of alkali-soluble celluloses with either crystal form of cellulose-I (Cell-I; steam exploded spruce pulp) or cellulose-II (Cell-II; regenerated from cotton/cuprammonium solution) were utilized. SEM observation on the lyophilized coagulated cellulose films revealed that all the films have basically porous structure more or less, constituted by collision of secondary particles. Coagulation from two types of cellulose solutions underwent in a quite different way as a function of Csa of coagulant: (1) For alkali-soluble Cell-II system, the existence of secondary particles was evident in the range of Csa≥20 wt% and the most dense structure was given when Csa=60—65 wt%, (2) For alkali-soluble Cell-I system, the secondary particles became detectable at Csa≥40 wt% and the coagulant with Csa=70 wt% gave the most dense structure of the film, and (3) the size of particles constituting the most dense films is smaller for Cell-II system than Cell-I system. The coagulant with Csa≥60 wt% proved to act as strong dehydrant from cellulose solutions by Raman spectroscopy and the neutralization rate of Cell-II system was much higher than Cell-I system. CP/MAS 13C NMR analysis showed that both densely coagulated films developed practically no intramolecular hydrogen bond at C3 position.

An attempt was made to extend the method for explaining monomer unit sequence distribution of a bi-component copolymer system proposed already by Kamide and Hisatani, in which both monomer units have possibility of yielding stereoregular homopolymers, to the system in which only one monomer is capable to give stereoregular homopolymer. The method includes a concept of correlation and non-correlation between sequence distributions of monomer unit and its cotacticity, and all of expressions of pentad sequences are described. Simultaneously, the sort of four kinds of n-length bi-component copolymer sequence has been enumerated up employing difference equation method, in which copolymer system only one monomer unit has stereoregularity. The method established in this paper was applied to poly(acrylonitrile-co-vinylidene chloride) sample as a model copolymer, of which 13C NMR peak assignment was already attained based on pentad sequence distribution [H. Yamazaki, K. Okajima, and K. Kamide, Polym. J., 20, 1143 (1988)].

Molecular Characterization of Nylon 6,6 and Its Dissolved State in Mixture of Calcium Chloride and Methanol