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Spin-contrast-variation neutron reflectivity obtains multiple reflectivity curves from a single sample and a single beam source. We used the strong point of the technique to reveal that, although methylated-perhydropolysilazane-derived silica layer has a higher porosity near the interface with acrylic urethane resin, the resin did not permeate the pore network., スピンコントラスト変調中性子反射率法は一つの試料一つのビームラインから複数の反射率曲線が得られる手法である。我々はその特徴を生かしてメチル化ポリシラザンから作られた多孔質シリカ界面においてアクリルウレタン樹脂は多孔質体内に入り込まないことを見出した。

Coulomb explosion experiments using linearly polarized intense 60 fs laser pulses were conducted for structural characterization of three dichloroethylene (DCE) isomers, 1,1-DCE, cis-1,2-DCE, and trans-1,2-DCE. Under relatively low laser intensity at 1.8 × 1014 W/cm2, mass-resolved momentum imaging (MRMI) for selected fragment ions of 35Cl+ and C2+ revealed different patterns for the three isomers. The C2+ ion fragmented from multiply charged trans-1,2-DCE was forced to leave perpendicularly to the direction of the laser polarization, due to recoil forces from adjacent cations. In contrast, the fast ions of C2+ from cis-1,2-DCE exhibited an isotropic distribution, whereas the fast ions of C2+ from 1,1-DCE recoiled along the laser polarization together with the slow C2+ ions, and thereby distinction of the three isomers was demonstrated. Coulomb explosion occurs predominantly at specific orientation, which is useful for potential applications of MRMI analysis to molecular structure assays.

A spin-contrast-variation neutron powder diffractometry technique that extracts the structure factor of hydrogen atoms, i.e. the contribution of hydrogen atoms to a crystal's structure factor, has been developed. Crystals of L-glutamic acid were dispersed in a D-polystyrene matrix containing 4-methacryloyloxy-2,2,6,6,-tetramethyl-1-piperidinyloxy to polarize their proton spins dynamically. The intensities of the diffraction peaks of the sample changed according to the proton polarization, and the structure factor of the hydrogen atoms was extracted from the proton-polarization-dependent intensities. This technique is expected to enable analyses of the structures of hydrogen-containing materials that are difficult to determine with conventional powder diffractometry.

We demonstrate isotope selective ionization of I79Br and I81Br isotopologues using field-free alignment induced by a linearly-polarized nanosecond laser pulse with rapid turn off at the maximum. Fo...

We developed a technique of spin-contrast-variation neutron reflectometry (SCV-NR). Polarized-neutron reflectivity curves of film samples vary as a function of their proton-polarization P. The P-dependent reflectivity curves of a polystyrene film was precisely reproduced using a common set of structure parameters and the P-dependent neutron scattering length. The reflectivity curve of poly (styrene-block-isoprene) (PSPI) presented a shoulder attributed to holes with the depth corresponding to one period of periodic lamellae on the free surface only at a specific P. In this way, structural information about specific surfaces or interfaces can be obtained by controlling the P., スピンコントラスト変調中性子反射率法を用いて高分子膜の測定を行った。ポリスチレン薄膜の測定においては核偏極に従って変化する反射率曲線は全て同一の構造因子を用いて綺麗に再現することができた。本結果は、スピン拡散機構によって表面や界面を含めて試料が均一に偏極していることを示したものであり、本手法から構造因子を高い信頼性をもって得られることを担保する結果となった。また、ミクロ相分離したブロック共重合体の測定では、核偏極によって特定の界面構造が選択的に得ることができることを示した。

Dynamic nuclear polarization (DNP) at low temperature (1.2 K) and high magnetic field (3.3 T) was applied to a contrast variation study in small-angle neutron scattering (SANS) focusing on industrial rubber materials. By varying the scattering contrast by DNP, time-of-flight SANS profiles were obtained at the pulsed neutron source of the Japan Proton Accelerator Research Complex (J-PARC). The concentration of a small organic molecule, (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO), was carefully controlled by a doping method using vapour sorption into the rubber specimens. With the assistance of microwave irradiation (94 GHz), almost full polarization of the paramagnetic electronic spin of TEMPO was transferred to the spin state of hydrogen (protons) in the rubber materials to obtain a high proton spin polarization (P H). The following samples were prepared: (i) a binary mixture of styrene–butadiene random copolymer (SBR) with silica particles (SBR/SP); and (ii) a ternary mixture of SBR with silica and carbon black particles (SBR/SP/CP). For the binary mixture (SBR/SP), the intensity of SANS significantly increased or decreased while keeping its q dependence for P H = −35% or P H = 40%, respectively. The q behaviour of SANS for the SBR/SP mixture can be reproduced using the form factor of a spherical particle. The intensity at low q (∼0.01 Å−1) varied as a quadratic function of P H and indicated a minimum value at P H = 30%, which can be explained by the scattering contrast between SP and SBR. The scattering intensity at high q (∼0.3 Å−1) decreased with increasing P H, which is attributed to the incoherent scattering from hydrogen. For the ternary mixture (SBR/SP/CP), the q behaviour of SANS was varied by changing P H. At P H = −35%, the scattering maxima originating from the form factor of SP prevailed, whereas at P H = 29% and P H = 38%, the scattering maxima disappeared. After decomposition of the total SANS according to inverse matrix calculations, the partial scattering functions were obtained. The partial scattering function obtained for SP was well reproduced by a spherical form factor and matched the SANS profile for the SBR/SP mixture. The partial scattering function for CP exhibited surface fractal behaviour according to q −3.6, which is consistent with the results for the SBR/CP mixture.

We present a method for fabricating photonic crystals (PCs) by polymerization-induced microphase separation of block copolymers (BCPs). Molecular weight of BCP for PCs is so large that it has been difficult for conventional solution casting and annealing methods to complete the microphase separation to form periodically ordered submicron structures. Our method overcomes the difficulty by inducing the microphase separation and transitions during the polymerization, when the molecular weight of the BCPs is small enough for the microphase separation and transitions. The microphase-separated structure is then enlarged while maintaining the self-similarity. We succeeded in fabricating PCs with reflection wavelength λm ≈ 1000 nm and a full width at half-maximum Δλ = 0.05λm by living-radical bulk block copolymerization of poly(methyl methacrylate)-block-polystyrene.

We have succeeded in observing Fe-ion-beam induced nanostructural change of MA956 oxide dispersion-strengthened (ODS) steel using anomalous small-angle X-ray scattering (ASAXS) diffractometry. The ASAXS curve shows a power-law scattering that follows the Porod’s law and an overlapped shoulder peak at the magnitude of scattering vector, Q, around 0.6 nm−1. As the X-ray energy approaches the absorption K-edge of Cr (5.990 keV), the intensity of the power-law scattering slightly decreases, but that of the shoulder peak remarkably increases. From these results, the power-law scattering is attributed to Cr-poor scatterers with a radius much larger than 5 nm, and the shoulder peak is attributed to Cr-rich α′ precipitates with a mean radius of 2.8 nm. After the ion-beam irradiation, intensity of the power-law scattering is nearly doubled, but the shoulder peak remains unchanged within an error of 2%. The latter result indicates that the irradiation-induced changes of radius and inter-precipitation distance of the α′ precipitates are smaller than 10%, and the change of their interface thickness is less than 0.5 nm. In this way, our ASAXS results guarantee an absence of irradiation-induced nanostructure change of specific kinds of precipitates together with statistical errors, while observing changes of other precipitates.

We develop a closed-cycle dynamic nuclear polarization (DNP) system for spin-contrast-variation (SCV) small-angle neutron scattering (SANS) and neutron reflectometry (NR) to increase the use of these techniques. Compared with our cryogen-filled DNP system, the closed-cycle system is made compact and can change the sample in a comparable time-scale, but achieved proton-polarization is only 11.2 and 20$\pm$3% for bulk and thin-film samples, respectively, whereas 32-37% is achieved with the cryogen-filled system. This is because cooling power of the recycling cold helium gas in the closed-cycle system is lower than that of superfluid helium in the cryogen-filled one. In order to improve the polarization with the closed-cycle system, we have to improve thermal contact between the sample and cold helium gas to minimize microwave heating of the sample.

We are developing time-resolved grazing-incidence small-angle scattering (GI-SAXS) system using a soft X-ray laser. As a first step, we carried out GI-SAXS measurements of optical grating and craters produced on gold surface by femtosecond laser ablation . We succeeded in observing the diffraction spots from the grating as expected, but the diffuse scattering from the craters was hidden in thermal noises of a soft X-ray charge-coupled device camera.

We propose and numerically simulate a method of laser isotope separation based on field-free alignment of isotopologues, utilizing an intense “switched” nanosecond (ns) laser field which is slowly turned on and rapidly turned off at the peak with the falling time of 200 fs. The femtosecond (fs) laser-induced alignment of isotopologues including heavy isotopes is severely disturbed by ionization because of their small ionization potential. Our simulations for I79Br and I81Br isotopologues demonstrate that the switched ns laser field can make isotopologues well-aligned with the reduced ionization probability at the laser intensity [I 0 = 2 TW/cm2 (= 2 × 1012 W/cm2)] which is an order-of-magnitude lower than a typical intensity (I 0 = 20 TW/cm2) for field-free alignment induced by a fs laser field. In our simulations, I i Br isotopologues (i = 79 or 81) aligned with the switched ns laser field are selectively ionized by an intense fs laser pulse at an appropriate time delay from the alignment pulse.

We investigated the dynamic nuclear polarization (DNP) of typical thermosetting polymers (two-component type epoxy resins ; Araldite ® Standard or Araldite® Rapid) doped with a (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO) radical. The doping process was developed by carefully considering the decomposition of TEMPO during the solidification of the epoxy resin. The TEMPO electron spin in each two-component paste decayed slowly, which was favorable for our study. Furthermore, despite the dissolved TEMPO, the mixture of the two-component paste successfully solidified. With the resulting TEMPO-doped epoxy-resin samples, DNP experiments at 1.2 K and 3.35 T indicated a magnitude of a proton-spin polarization up to 39%. This polarization is similar to that (35%) obtained for TEMPO-doped polystyrene (PS), which is often used as a standard sample for DNP. To combine this solidification of TEMPO-including mixture with a resin-casting technique enables a creation of polymeric target materials with a precise and complex structure.

分子整列と非共鳴多光子イオン化を利用した同位体選択的イオン化の研究を行っている。重元素への適応可能性を検討するため、IBrのBr同位体混合ガスを対象に、ナノ秒パルスの後半部分をフェムト秒パルスによって発生したプラズマで打ち消したswitchedナノ秒パルスによる分子整列、ならびにフェムト秒パルスによる同位体選択的イオン化の理論予測を行った。現実的な実験条件で、イオン収量比がI81Br/I79Br＝0.7～1.6の範囲で変動した。, 33rd Symposium on Chemical Kinetics and Dynamics (第33回化学反応討論会)

We demonstrate that the methodology of frequency-resolved optical gating (FROG) is applicable to time-resolved reflection spectroscopy of a plasma mirror in the vacuum-ultraviolet (VUV) region. Our recent study [R. Itakura et al. Opt. Express 23, 10914 (2015)] has shown that a VUV waveform can be retrieved from a VUV reflection spectrogram of a plasma mirror formed on a fused silica (FS) surface by irradiation with an intense femtosecond laser pulse. Simultaneously, the increase in the reflectivity with respect to the Fresnel reflection of the unexcited FS surface can be obtained as a time-dependent reflectivity of the plasma mirror. In this study, we update the FROG analysis procedure using the least-square generalized projections algorithm. This procedure can reach convergence much faster than the previous one and has no aliasing problem. It is demonstrated that a significantly chirped VUV pulse as long as 1 ps can be precisely characterized.

We demonstrate laser nitrogen isotope separation, which is based on field-free alignment and angular-dependent ionization of 14N2 and 15N2 isotopologues. A linearly polarized short laser pulse (λ ~ 795 nm, Δτ ~ 60 fs) creates rotational wave packets in the isotopologues, which periodically revive with different revival times as a result of different moments of inertia. Another linearly polarized short laser pulse (λ ~ 795 nm, Δτ ~ 60 fs) ionizes one of the isotopologues selectively as a result of their different angular distributions. In the present experiments, the ion yield ratio R [=I(15N2 +)/I(14N2 +)] can be changed in the range from 0.85 to 1.22, depending on the time delay between the two laser pulses.

We compared dynamic nuclear polarization (DNP) behavior of electron-beam irradiated polyethylene (e-PE) with that of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO)-doped polystyrene (T-PS). Growth and decay rates of nuclear polarization P n of e-PE increased linearly with increasing concentration C e of free radicals, whereas those of T-PS increased with square of C e . From these results, we suggest that the pair of alkyl radicals produced by the radiolysis, –CH 2 –CH 2 –CH 2 – → –CH 2 –CH –CH 2 – + H , and the subsequent hydrogen abstraction reaction, H + –CH 2 –CH 2 –CH 2 – → H 2 + –CH 2 –CH –CH 2 – in e-PE plays an important role on DNP by the cross effect, whereas T-PS is polarized by a pair of unspecified TEMPO radicals accidentally located nearby. We propose that higher P n would be expected by optimizing the inter-radical distance within the pair in e-PE and other irradiated samples.

By combining two methods of selective doping of paramagnetic species into a microdomain and small-angle neutron scattering (SANS), thespatially inhomogeneous proton polarizationcreated by dynamic nuclear polarization (DNP) has been precisely evaluated. A lamella-forming diblock copolymer composed of polystyrene (PS) and polyisoprene (PI) block chains (PS-b-PI) was employed, the SANS profile of which clearly shows scattering peaks up to the third order due to interlamellar interference. As a source of electron spin for DNP, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) was doped into one or other of the microdomains; samples with PS or PI microdomains selectively doped with TEMPO are designated PS.-b-PI and PS-b-PI., respectively. The SANS intensity at the first- and third-order peaks is well reproduced by assuming that the proton polarization is homogeneous throughout the sample, but that at the second-order peak cannot be explained by this assumption. This anomaly regarding the second-order peak was successfully explained by a model postulating that proton polarization in a doped microdomain decreases with increasing distance from the interface with a neighbouring doped microdomain. The decrease in proton polarization at the centre of a doped microdomain was estimated to be 0.07 (2) for PS-b-PI.and 0.05 (1) for PS.-b-PI, relative to constant proton polarization in a doped microdomain. The inhomogeneous proton polarization results from two competing dynamic processes,i.e.spin diffusion from doped to undoped microdomains, and spin lattice relaxation occurring on the pathway of proton spin diffusion.

On the Jinkoji coast facing the Pacific Ocean, beach nourishment using 8.7×104m3 of gravel with grain sizes ranging from 3 to 15 mm had been carried out by April 2008. After beach nourishment, a stable beach was formed between the artificial headlands. In response to the success in recovering a sandy beach, beach nourishment was also planned for the Komiyasaku coast south of the Jinkoji coast along with the Oritsu coast, which is a famous recreational beach. In this case, beach nourishment using gravel is considered to have been avoided for recreational use. Taking these conditions into account, beach nourishment using medium sand was planned. A stable beach topography produced by gravel nourishment was reproduced numerically using the BG model, while incorporating the effect of changing the grain size into the model, and the effectiveness of the model was confirmed. Then the model was applied to gravel nourishment along the Komiyasaku coast and to beach nourishment using medium sand at the Oritsu coast.

We have carried out a dynamic nuclear polarization (DNP) study of proton spins of UV-irradiated solid butanol containing phenol at 0.1-1%. By the aid of butyl free radicals produced by the photolysis, the butanol sample was dynamically polarized up to the polarization of 1.4+/-0.1% at 1.5 K and 1.2 T, which is about 4000 times larger than that at the thermal equilibrium at an ambient temperature. Unlike persistent free radicals such as nitroxy and trityl free radicals commonly used for DNP, the butyl free radicals immediately decay by melting. We propose that free radicals produced by UV-photolysis are applicable to the DNP-enhanced hyperpolarized liquid-state NMR (Ardenkjaer-Larsen et al. [6]). The hyperpolarization of the UV-irradiated samples should remain longer than that of the samples having persistent free radicals, because of the absence of the free radicals after the melting in the UV-irradiated samples.

We carried out a dynamic nuclear polarization (DNP) study of high- and low-crystallinity polyethylene films defined as HPE and LPE, respectively, which were doped with TEMPO (2,2,6,6-tetra-methyl-piperidine-1-oxyl) by the same amount (1×10 19 spins/cm 3 ). The proton polarization of 32±3% was obtained for LPE and 23±4% for HPE at 3.35 T and 1.4 K. With increase in the concentration of TEMPO, the electron spin resonance (ESR) linewidth of TEMPO in HPE increased more steeply than that in LPE, indicating that TEMPO did not incorporated into the crystalline part, and was localized only at the amorphous part, hence the local concentration of TEMPO in the amorphous regions of HPE varied more steeply than that of LPE with the net amount of TEMPO fed into the film. We suggest that the smaller nuclear polarization for HPE is related to the localization of TEMPO in the smaller amorphous regions.

Behavior of the hydrogen isotope in recombination reactions, H+H→H2 H+T→HT and T+T→T2 under pressurized conditions at 1.6 K were investigated using liquid helium as cryogenic reaction media by radiochemical methods. Pressure effects were observed in changes of isotope ratio HT/T2. It became clearer that the balance of changes in bubble energy effective mass associated with energy and chemical potential contributed to the recombination reactions through bubble states. It was suggested that bubble radius was decreased significantly at higher pressure.

A model for predicting bathymetric and grain size changes considering equilibrium slopes corresponding to the composition of grain size and each grain size was applied to predict the beach changes on the Chigasakinaka coast. The cross-shore sorting of sand, in which the grain size gradually decreases with increasing depth, and the formation of a gradually changing longitudinal slope were reproduced well. The diffusion of colored sand with different grain sizes placed on the shoreline and at a depth of 4 m was predicted and compared with the results of a field observation using colored sand on the Chigasakinaka coast. Both results were in good agreement.

A model for predicting the formation and deformation of the multiple bars is developed. The model developed by Shimizu et al. (2008), which can predict 2-D formation of the multiple bars applying the contour-line-change model, is further expanded to predict 3-D formation and deformation of the multiple bars. Taking the beach changes around Fukude fishing port, where multiple bars developed before the construction of the breakwater, but it disappeared after the construction of the breakwater obstructing longshore sand transport as an example, numerical simulations were carried out. The formation and deformation of the multiple bars were predicted by the model.

After the completion of beach nourishment using 87,000 m3 of gravel with the grain size between 3 and 15 mm in April 2008 at the Jinkoji coast which faces the Pacific Ocean and is surrounded by artificial headlands, boring test and core sampling on the beach were carried out to investigate the formation of the gravel layers. It was found that gravel is deposited with a slope of 1/8 on foot of the seawall, exhibiting the foot protection effect to the seawall, and the nourishment gravel is stably deposited without offshore discharge.

We carried out electron spin resonance (ESR) study of irradiated solid H 2 and para -H 2 . H-atom, e − , and H 6 + lines were observed. The H-atom radicals diffuse in solid H 2 by the tunneling chemical reaction H+H 2 →H 2 +H below 4 K, and by the thermally activated process above 5 K. These decay via H–H recombination. Yield of trapped electrons e − produced by the radiolysis of solid para -H 2 increases with increase in the concentration of added isotopic hydrogen, HD or D 2 . These decay via geminate recombination with positive ions with a half-life of 8 h at 4 K. H 6 + ion is an ionic hydrogen radical whose spectrum has firstly been observed in irradiated solid para -H 2 . H 6 + ions diffuse in solid H 2 by sequence of H 6 + +H 2 →H 2 +H 6 + reactions, and terminate by the isotope-exchange reaction H 6 + +HD→H 5 D + +H 2 or H 6 + +D 2 →H 4 D 2 + +H 2 . Unlike H 6 + , isotopically substituted H 5 D + and H 4 D 2 + cannot diffuse in solid para -H 2 . Rate-determining step of their decay is charge recombination with e − .

We have measured electron spin resonance (ESR) spectra of H 6 + and H 4 D 2 + ions produced in γ-ray irradiated solid parahydrogen. Anisotropic hyperfine-coupling constants for H 6 + and H 4 D 2 + determined by the analysis of ESR lines at 4.2 K were −0.06 and −0.12 mT, respectively, which were opposite in sign to and much smaller than theoretical results of 1.17–1.25 mT. Although no change was observed in H 6 + , the constant for H 4 D 2 + increased to be 1.17 mT at 1.7 K, which is very close to the theoretical value. We concluded that H 6 + both at 4.2 and 1.7 K and H 4 D 2 + at 4.2 K should be in a large precessional motion with the angle of 57–59°, but the precession of H 4 D 2 + is stopped at 1.7 K.

A restoration plan recovering sandy beaches at Tennozaki in Lake Kasumigaura was investigated. Past lakeshore changes were first investigated through the comparison of old map and aerial photographs. A stable shoreline of a pocket beach was predicted by applying a modified Hsu model (Serizawa et al., 1996). Numerical simulation using a contour-line-change model considering the change in grain size proposed by Kumada et al. (2003) was also carried out. Three-dimensional beach changes when beach nourishment was carried out were predicted by this model.

Beach changes on the Narusawa, Taga and Kawarago coasts in Hitachi City in Ibaraki Prefecture were investigated on the basis of the aerial photographs and field observation. The shoreline changes between 1984 and 2006 were studied. Sea cliff extends along these coasts, and narrow sandy beaches have been formed mainly by the sand supply from small rivers. The breakwaters of Kawarago port and Ohse fishing port were constructed, resulting in the formation of the wave shelter zone. Longshore sand transport from outside to inside the wave shelter zone was induced, causing erosion outside the wave shelter zone and accretion inside it. In the eroded zone, sea cliff is exposed to waves and abrasion by gravels is underway. To protect these beaches, comprehensive management such as the sand recycling is required.

Field experiment on changes in thickness of the sand mixing layer was investigated on the Jinkoji coast, where beach nourishment using coarse material has been carried out. Four trenches were excavated on the shore face, andcoarse material, fine sand and their mixture were filled in each trench, and subsequent mixing due to waves were investigated. Comparing the mobility of sandy beach composed of various materials, minimum mobility was obtained at gravel, and the mobility of the beach composed of the mixture of sand and gravel was the largest, implying that the effect of the beach nourishment using the mixture of sand and gravel is inferior to that using gravel only.

On the basis of cross-shore sand transport under the action of long period waves and standing waves reflecting from the seabed slope given by Bowen (1980) and Katoh (1984), a model for predicting the development of multi-bar system was proposed by applying the contour-line-change model. The increase in the intervals between the bars and the decay of the relative height of bars in the cross-shore direction were predicted well. The possibility of the recovery of the multi-bar system by beach nourishment using fine sand is also shown.

The behavior of recombinations of H+H→H2, H+T→HT and T+T→T2 in liquid helium at cryogenic temperature of 1.6 K was investigated under pressurized condition using radiochemical methods. It was found that the isotope ratios of H2, HT and T2 were changed with the pressure. The changes will contribute to the bubble formation, chemical potential and the effective masses of H and T. This work is a preliminary information to carry out chemical reactions in liquid helium.

On the Kashimanada coast, fine sand was selectively transported and deposited in the wave-shelter zone behind the offshore breakwater built on both ends of the coastline, whereas beach was eroded in the central part of the coastline. As a measure, artificial headlands have been constructed on this coast, but beach erosion is still severe. The contour-line-change model considering the effect of changes in grain size was applied to this coast, and the effect of the measure was evaluated. The differences between the total accreted and eroded volumes of sand in the condition with/without headlands became 7.4×106 and 8.1×106 m3. Thus, it was found that the movement of approximately 8.0×106 m3 of sand was controlled by headlands.

A model for predicting the distribution of the habitat of Japanese hard clam Meretrix lamarckii was developed, taking the life history between a larva and an adult clam into account. The coupling was made with the contour-line-change model by proposed Kumada et al.(2005), which considers the sorting effect due to change in grain size. The habitat change corresponding to the development of the clam as well as the spatial change in habitat can be predicted by this model. The model was applied to the Hazaki coast. Predicted habitat was in good agreement with the measured habitat. This model can be used for predicting the effect of release of this clam to increase the clam resources.

Kasuga (2006) has been measuring the lakeshore elevation at a point in front of the seawall at Ohyama region in Lake Kasumigaura once a day since 1993. Due to this observation, the elevation at the point showed a strong periodicity of a year. To investigate the cause of the changes, original data taken by Kasuga was analyzed as well as seabed sounding and sampling test of seabed materials. Wave forecasting and numerical simulation using the contour-line-change model was carried out. It was found that this periodic variation of the elevation was induced by the seasonal changes in direction of longshore sand transport on a pocket beach between a drainage gate and lakeshore plants.

To address the question as to how small-angle scattering is effectively applied to the cell, i.e., ahierarchically ordered system comprising multi-components of macro and small molecules, the size ofwhich ranges from 100 μm to several μm, we reconstructed SANS-J (pinhole small-angle neutronscattering spectrometer at research reactor JRR3, Tokai) to focusing & polarized neutron small-anglespectrometer (SANS-J-II), by employing focusing neutron lenses and high resolution photomultiplier.Consequently, an accessible minimum wave number qmin was improved from 3×10-3 A-1 to mediumultra-small angle scattering of 3×10-4 A-1. The focusing USANS method, thus developed, is crucialto fill the gap in wave number q between those covered by a double crystal method and by a conventionalpin-hole method.

Shoreline changes of the Akiya coast located in Sagami Bay were investigated on the basis of the comparison of aerial photographs. A breakwater of Kuruwa fishing port was extended forming a wave shelter zone. This induced longshore sand transport from outside to inside the wave shelter zone. Sand accumulated inside the wave shelter zone, whereas beach erosion occurred on the nearby coast. Tracer test using sand with various grain sizes was carried out. The contour-line-change model considering change in grain size given by Kumada et al.(2005) was applied to the coast to investigate the effect of beach nourishment using materials with different grain sizes. It is concluded that beach nourishment using sand composed of coarse materials is effective to recover the stable beach without damages to offshore sea grass field.

On the basis of the concept given by Noshi et al.(2005), a contour-line change model considering longitudinal slope corresponding to the grain size composition was developed, while improving the model given by Kumada et al.(2005). It is assumed that the equilibrium slope changes in response to the change in composition of grain size of bed materials, but the change is slow, and it gradually approaches an equilibrium slope with time. The model was applied to three coasts, and the applicability was confirmed. Longshore changes in foreshore slope, which was difficult to predict in the previous model, were able to predict in the model. Furthermore, the formation of the concave and convex profiles in the eroded and accreted zones became capable to predict.