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We theoretically investigate the preparation of mid-infrared (MIR) spectrally-uncorrelated biphotons from a spontaneous parametric down-conversion process using doped LN crystals, including MgO doped LN, ZnO doped LN, and In2O3 doped ZnLN with doping ratio from 0 to 7 mol%. The tilt angle of the phase-matching function and the corresponding poling period are calculated under type-II, type-I, and type-0 phase-matching conditions. We also calculate the thermal properties of the doped LN crystals and their performance in Hong-Ou-Mandel interference. It is found that the doping ratio has a substantial impact on the group-velocity-matching (GVM) wavelengths. Especially, the GVM2 wavelength of co-doped InZnLN crystal has a tunable range of 678.7 nm, which is much broader than the tunable range of less than 100 nm achieved by the conventional method of adjusting the temperature. It can be concluded that the doping ratio can be utilized as a degree of freedom to manipulate the biphoton state. The spectrally uncorrelated biphotons can be used to prepare pure single-photon source and entangled photon source, which may have promising applications for quantum-enhanced sensing, imaging, and communications at the MIR range., 11 pages, 9 figures

The solid electrolyte interphase (SEI) is regarded as the most complex but the least understood constituent in secondary batteries using liquid and solid electrolytes. The nanostructures of SEIs were recently reported to be equally important to the chemistry of SEIs for stabilizing Li metal in liquid electrolyte. However, the dearth of such knowledge in all-solid-state battery (ASSB) has hindered a complete understanding of how certain solid-state electrolytes, such as LiPON, manifest exemplary stability against Li metal. Characterizing such solid-solid interfaces is difficult due to the buried, highly reactive, and beam-sensitive nature of the constituents within. By employing cryogenic electron microscopy (cryo-EM), the interphase between Li metal and LiPON is successfully preserved and probed, revealing a multilayer mosaic SEI structure with concentration gradients of nitrogen and phosphorous, materializing as crystallites within an amorphous matrix. This unique SEI nanostructure is less than 80 nm and is shown stable and free of any organic lithium containing species or lithium fluoride components, in contrast to SEIs often found in state-of-the-art organic liquid electrolytes. Our findings reveal insights on the nanostructures and chemistry of such SEIs as a key component in lithium metal batteries to stabilize Li metal anode.

Ultrafast quantum optics with time-frequency entangled photons is at the forefront of progress towards future quantum technologies. However, to unravel the time domain structure of entangled photons and exploit fully their rich dimensionality, a single-photon detector with sub-picosecond temporal resolution is required. Here, we present ultrafast single-photon detection using an optical Kerr gate composed of a photonic crystal fiber (PCF) placed inside a Sagnac interferometer. A near-rectangle temporal waveform of a heralded single-photon generated via spontaneous parametric down-conversion is measured with temporal resolution as high as 224 ± 9 fs. The large nonlinearity and long effective interaction length of the PCF enables maximum detection efficiency to be achieved with only 30.5 mW gating pulse average power, demonstrating an order-of-magnitude improvement compared to optical gating with sum-frequency generation. Also, we discuss the trade-off relationship between detection efficiency and temporal resolution.

Determination of excited states of near-infrared (NIR) bioimaging dyes is a challenging theoretical task because of their energy levels with a small gap and the presence of solvation. In the previous study, we showed that the development of the reference interaction site model coupled with the complete active space second-order perturbation theory, the RISM-CASPT2 method, and its extension with the density matrix renormalization group enabled high accuracy prediction of the photochemical properties of bioimaging-related fluorescent molecules in solution (Shimizu et al.

The solid electrolyte interphase (SEI) is regarded as the most complex but the least understood constituent in secondary batteries using liquid and solid electrolytes. The nanostructures of SEIs were recently reported to be equally important to the chemistry of SEIs for stabilizing Li metal in liquid electrolyte. However, the dearth of such knowledge in all-solid-state battery (ASSB) has hindered a complete understanding of how certain solid-state electrolytes, such as LiPON, manifest exemplary stability against Li metal. Characterizing such solid-solid interfaces is difficult due to the buried, highly reactive, and beam-sensitive nature of the constituents within. By employing cryogenic electron microscopy (cryo-EM), the interphase between Li metal and LiPON is successfully preserved and probed, revealing a multilayer mosaic SEI structure with concentration gradients of nitrogen and phosphorous, materializing as crystallites within an amorphous matrix. This unique SEI nanostructure is less than 80 nm and is shown stable and free of any organic lithium containing species or lithium fluoride components, in contrast to SEIs often found in state-of-the-art organic liquid electrolytes. Our findings reveal insights on the nanostructures and chemistry of such SEIs as a key component in lithium metal batteries to stabilize Li metal anode.

Conventional optical synthesis, the manipulation of the phase and amplitude of spectral components to produce an optical pulse in different temporal modes, is revolutionizing ultrafast optical science and metrology. These technologies rely on the Fourier transform of light fields between time and frequency domains in one-dimensional space. However, within this treatment it is impossible to incorporate the quantum correlation among photons. Here we expand the Fourier synthesis into high dimensional space to deal with the quantum correlation, and carry out an experimental demonstration by manipulating the two-photon probability distribution of a biphoton in two-dimensional time and frequency space. As a potential application, we show manipulation of a heralded single-photon wave packet, which is never explained by the conventional one-dimensional Fourier optics. Our approach opens up a new pathway to tailor the temporal characteristics of a biphoton wave packet with high dimensional quantum-mechanical treatment. We anticipate such high dimensional treatment of light in time and frequency domains could bridge the research fields between quantum optics and ultrafast optical measurements., Comment: 12 pages, 7 figures

Light-harvesting efficiency can be prominently increased by using ternary blend polymer solar cells, in which a wide-bandgap crystalline polymer is incorporated into a binary blend of a low-bandgap polymer and a fullerene derivative. This is partly due to the complementary absorption bands over a wide wavelength range, and partly ascribed to the thick photoactive layer. As a result, the best power conversion efficiency of 9.40% was obtained for the ternary blend device with a thickness of ≈300 nm.

Free-space optical (FSO) communications are becoming promising schemes for high-capacity wireless links due to their plentiful characteristics originated from higher carrier frequency. These characteristics also yield a greater security advantage over radio frequency counterparts: the physical ability of a wiretapper is reasonably restricted due to the high directionality of communication beam and the line-of-sight configuration of the link. Secret key agreement over FSO links (FSO-SKA) employs this security advantage as well as the post-processing over an authenticated public channel to establish an information-theoretic secure key which cannot be broken even with unbounded computer resources. In the previous works, the authors demonstrated the full-field implementations of FSO-SKA with a 7.8-km FSO link testbed including a probing station to estimate the possible wiretapping risks from the sidelobe of the communication beam. In the demonstration, however, there is still room to improve the secret key rate by exploiting the optical fading which contains additional information about random states of the FSO links. We here propose a novel protocol for FSO-SKA employing such channel state information. In the protocol, the legitimate receiver decides whether to discard the received symbols or not according to the received optical power at the time. Based on the experimental data from the FSO link testbed, we demonstrate that the proposed protocol improves the secret key rate compared with our previous result. To our best knowledge, this is the first demonstration that exploits the effect of atmospheric turbulences to improve the security performance of communication systems. We anticipate that this idea will be applicable on the broader areas of FSO communications and opens a way toward practical wireless network spanned by FSO links.

In recent years, the demand for high-speed communication has been increasing. Satellite laser communication is one of the infrastructures that can realize this demand. However, in free-space optics (FSO) that use satellite laser communications, a scintillation occurs when the light passes through the atmosphere, resulting in a burst error. To prevent this, a strong error correction code is required. The polar code, one of such channel coding schemes, has been recently proposed. We have considered applying polar codes into FSO channels and have evaluated its performances through computer simulations. However, the experiments of polar code transmission in an outdoor FSO channel has not been studied. Therefore, in this paper, we conduct an experiment in polar code transmission in a terrestrial FSO channel instead of a satellite FSO as the first step of study, and then analyze the performance from the transmission results.

This study extends Hirano and Yanagawa (Rev Econ Stud 84(1):406–443, 2017) to an asymmetric two-country model and examines bubbles effects on each country’s long-run economic growth rate. This study also provides numerical examples with respect to the relationship between each country’s growth rate and their financial frictions in the balanced growth equilibria with bubbles and without bubbles. It shows that foreign bubbles have positive and negative effects on both countries’ growth rates, and which effect dominates depends on the level of financial development in both countries. In this study, the positive effect of bubbles tends to dominate when the total level of financial frictions in both countries is relatively low. When the total effect of bubbles on the growth rate is positive, the burst of foreign bubbles leads to a decrease in the growth rate in both countries. This implies that there is a positive correlation between foreign bubbles and the domestic as well as the foreign country’s growth rate.

We experimentally demonstrate a polarization-entangled photon source at 810 nm using a type-II phase-matched periodically poled potassium titanyl phosphate (PPKTP) crystal pumped by a low-cost, broadband laser diode with a central wavelength of 405 nm and a typical bandwidth of 0.53 nm. The PPKTP crystal is placed in a Sagnac loop to realize the compact size and high stability. The downconverted biphotons, the signal and the idler, have typical bandwidths of 5.57 and 7.32 nm. We prepare two Bell states | Ψ + ⟩ and | Ψ − ⟩ with the fidelities of 0.948 ± 0.004 and 0.963 ± 0.002 . In the polarization correlation measurement, the visibilities are all higher than 96.2%, and in the Bell inequality test, the S value can achieve 2.78 ± 0.01 . This high-quality and low-cost entangled photon source may have many practical applications in quantum information processing.

Summary Silicon with a high theoretical capacity (3,579 mAh/g) is a promising anode candidate for lithium-ion batteries. However, commercialization is still impeded by low Coulombic efficiency, caused by solid electrolyte interphase (SEI) formation and trapped lithium (Li)-silicon (Si) alloy during repeated volume change. Quantifying capacity losses from each factor is crucial to formulate rational design strategies for further improvement. In this work, titration-gas chromatography and cryogenic transmission electron microscopy are applied to characterize the evolution of trapped Li-Si alloy and SEI growth in a silicon thin-film anode. It is found that continuous growth of the SEI is the dominant factor for lithium inventory loss during cycling, with only a marginal increase in trapped Li-Si alloy. This study offers a quantitative approach to differentiate Li in the SEI from trapped Li in Li-Si alloy through a silicon thin-film anode, providing unique insights into identifying critical bottlenecks for developing Si anodes.

The sol-gel transition entropy is estimated by using a modified Clapeyron-type equation for κ-carrageenan hydrogel systems under load. The effect of alkali metal salts on the sol-gel transition behavior is also investigated. The transition temperature decreases with increasing compressional stress, while the transition entropy remains unchanged. Both the transition entropy and the transition temperature at the zero stress limit vary almost in accordance with the Hofmeister series, but the inversion occurs for RbCl and CsCl. For the gels examined, a positive correlation exists between the transition entropy and the transition temperature at the zero stress limit.

We have studied the effects of the oxidizing species on the cobalt radioactivity buildup behavior in boiling water reactors (BWRs) using both experimental results and existing literature data. The oxidizing species used to simulate the normal water chemistry (NWC) condition of BWRs were 200 ppb dissolved oxygen or 200 ppb hydrogen peroxide accompanied by 100 ppb dissolved oxygen. We found that the amount of cobalt deposited on stainless steel specimens in the oxygen-based water chemistry (200 ppb dissolved oxygen) was larger than that in the hydrogen peroxide–based water chemistry (200 ppb hydrogen peroxide and 100 ppb dissolved oxygen). The rate of cobalt deposition in the former chemistry was more than four times larger than that in the latter chemistry. This difference in cobalt deposition behavior can be attributed to two properties of oxides: surface morphology and composition. The film formed in the oxygen-based environment was less dense than the film formed in the hydrogen peroxide–based e...

Endurance training improves oxidative stress and vascular endothelial dysfunction in patients with chronic heart failure (CHF). However, patients with CHF and an implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy-defibrillator (CRT-D) often avoid endurance training for fear of ICD shock. Recent studies have reported that stretching exercises enhance antioxidant activity and improve vascular responses. Therefore, we aimed to assess the effects of 4 weeks of stretching exercises on oxidative stress and vascular endothelial function in patients with CHF with an ICD or CRT-D.Fifty sedentary patients with CHF (78% males; mean age = 70 ± 9 years; left ventricular ejection fraction = 26% ± 8%) with an ICD or CRT-D were randomly divided into a group that performed 4 weeks of stretching exercises (stretching group) and a group that continued a sedentary lifestyle (control group). We compared the reactive hyperemia peripheral arterial tonometry (RH-PAT) index and blood parameters, such as von Willebrand factor (vWF), malondialdehyde-modified low-density lipoprotein cholesterol (MDA-LDL), reactive oxygen species (ROS), high-sensitivity C-reactive protein, pentraxin 3, and fibrinogen between the 2 groups before and after the 4-week study period.In the stretching group, a significant increase in the RH-PAT index and significant decreases in vWF, MDA-LDL, ROS, and fibrinogen concentrations were observed after the study compared with before (all P.05). No significant changes were observed in the control group.Four weeks of stretching exercises improved vascular endothelial dysfunction through attenuation of oxidative stress in sedentary patients with CHF with an ICD or CRT-D.

Spectrally intrinsically uncorrelated biphoton states generated from nonlinear crystals are very important but rare resources for quantum photonics and quantum information applications. Previously, such biphoton states were generated from several kinds of crystals, however, their wavelength ranges and nonlinear efficiencies were still limited for various applications. In order to explore new crystal for wider wavelength range and higher nonlinear efficiency, here we theoretically study the generation of spectrally uncorrelated biphoton states from 14 crystals in the `BBO family', including BBO, CLBO, KABO, KBBF, RBBF, CBBF, BABF, BiBO, LBO, CBO, LRB4, LCB, YCOB, and GdCOB. They satisfy three kinds of group-velocity matching condition from near-infrared to telecom wavelengths. Furthermore, heralded single photons can be generated with a purity as high as 0.98, which is achieved without any narrow filtering. The indistinguishability of photons from independent sources is examined by the Hong-Ou-Mandel interference, which results in a visibility of 98% also without any further filtering, i.e., photons from different heralded single-photon sources are highly indistinguishable. Our study may provide single-photon sources with good performance for quantum information processing at near-infrared and telecom wavelengths., Comment: 10 pages, 6 figures

Light incident upon molecules trigger fundamental processes in diverse systems present in nature. However, under natural conditions, such as sunlight illumination, it is impossible to assign known times for photon arrival owing to continuous pumping, and therefore, the photo-induced processes cannot be easily investigated. In this work, we theoretically demonstrate that characteristics of sunlight photons such as photon number statistics and spectral distribution can be emulated through quantum entangled photon pair generated with the parametric down-conversion (PDC). We show that the average photon number of the sunlight in a specific frequency spectrum, e.g., the visible light, can be reconstructed by adjusting the PDC crystal length and pump frequency, and thereby molecular dynamics induced by the pseudo-sunlight can be investigated. The entanglement time, which is the hallmark of quantum entangled photons, can serve as a control knob to resolve the photon arrival times, enabling investigations on real-time dynamics triggered by the pseudo-sunlight photons., Comment: 7 pages

We report a simple scheme for direct generation of frequency-bin entangled photon pairs via spontaneous parametric downconversion. Our fabricated nonlinear optical crystal with two different poling periods can simultaneously satisfy two different, spectrally symmetric nondegenerate quasi-phase-matching conditions, enabling the direct generation of entanglement in two discrete frequency-bin modes. Our produced photon pairs exhibited Hong-Ou-Mandel interference with high-visibility beating oscillations, a signature of two-mode frequency-bin entanglement. Moreover, we demonstrate deterministic entanglement-mode conversion from frequency-bin to polarization modes, with which our source can be more versatile for various quantum applications. Our scheme can be extended to direct generation of high-dimensional frequency-bin entanglement, and thus will be a key technology for frequency-multiplexed optical quantum information processing.

The rapidly growing technological demand for lithium-ion batteries has prompted the development of novel cathode materials with high energy density, low cost, and improved safety. High voltage spinel, LiNi0.5Mn1.5O4 (LNMO), is one of the most promising candidates yet to be commercialized. The two primary obstacles for this material are the inferior electronic conductivity and fast capacity degradation in full cells due to the high operating voltage. By systematically addressing these limitations, we successfully develop a thick LNMO electrode with areal capacity loadings up to 3 mAh·cm−2. The optimized thick electrode is paired with a commercial graphite anode at both the coin cell and pouch cell level, achieving a full cell capacity retention as high as 72% and 78%, respectively, after 300 cycles. We attribute this superior cycling stability to careful optimizations of cell components and testing conditions, with a specific focus improving electronic conductivity and high voltage compatibility. These results suggest precise control of materials quality, electrode architecture and electrolyte optimization can soon support the development of a cobalt-free battery system based on a thick LNMO cathode (>4 mAh·cm2), which will eventually meet the needs of next-generation Li-ion batteries with reduced cost, improved safety, and assured sustainability.

Free-space optical (FSO) communications can offer secure connectivity thanks to the high directionality of the laser beam and the line-of-sight configuration. These security advantages are employed to realize high-speed key establishment between two distant parties, which is provably secure against an eavesdropper with unlimited computational resources. Besides, a well-maintained laser beam divergence allows group key agreement (GKA) among multiple parties. Here, we propose a novel method of GKA over FSO link—FSO-GKA. After numerically characterizing fundamental behaviors, we present a proof-of-concept demonstration of FSO-GKA using a 7.8-km terrestrial link. We achieve a group key rate of roughly 8 Mbps over a 58dB-loss channel based on 10-MHz on-off keying. We also investigate information leakage risks under several atmospheric conditions, which provides the basis for security certification of FSO-GKA. Our proposed scheme shows a new way to construct high-speed key exchange platforms.

Japanese animation, anime, has long been regarded as a niche culture reserved for anime otaku in Japan. The word anime otaku refers to individuals who spend most of their time alone at home, watching anime. However, in recent years, prototypical anime otaku have changed their behavioral patterns, resulting in a new movement called anime pilgrimage. Anime pilgrimage involves traveling to locations that resemble particular scenes in anime pieces, even though the locations themselves may be ordinary places. The authors constructed two models to describe the determinants of visit intention and destination loyalty based on research into ordinary and film tourism. The results suggested that, during the pre-tour period, otaku are motivated by the desire for interaction with other otaku and the wish to visit a new location. Moreover, they are also seeking to interact with the local people, and such experiences result in higher destination loyalty during the post-tour period.

Time-frequency duality plays a pivotal role in modern optical science and engineering. Conventional duality, which is connected by one-dimensional Fourier transformation, is insufficient for characterizing quantum mechanical correlations in the time-frequency behavior of multiple photons; a higher-dimensional treatment is required. The authors directly measure the two-photon distributions of generated biphotons in both frequency and time domains, and show that they satisfy the Fourier-limited condition in two-dimensional time and frequency space, but not in conventional one-dimensional space. This study helps to pave the way to tomorrow's quantum optical technologies.

The difference and sum-frequency distribution of the biphoton wavefunctions were extracted by applying a Fourier transform on the time-domain Hong-Ou-Mandel interference (HOMI) and the NOON state interference (NOONI) patterns.

In this work, we experimentally manipulate the spectrum and phase of a biphoton wave packet in a two-dimensional frequency space. The spectrum is shaped by adjusting the temperature of the crystal, and the phase is controlled by tilting the dispersive glass plate. The manipulating effects are confirmed by measuring the two-photon spectral intensity (TSI) and the Hong-Ou-Mandel (HOM) interference patterns. Unlike the previous independent manipulation schemes, here we perform joint manipulation on the biphoton spectrum. The technique in this work paves the way for arbitrary shaping of a multi-photon wave packet in a quantum manner., Comment: 4 pages, 4 figures

The author noticed that the published paper contained error. Unfortunately, Table 2 was incorrectly presented. Given in this paper is the correct table.

Previous research has shown that if WOM (word-of-mouth) receivers are exposed to a video message in which a person says that he/she made great efforts to earn money and purchase an attractive product, they feel benignly envious and have higher WTP (willingness to pay) for the product. In contrast, if receivers are exposed to another message in which a person says that he/she made no effort to earn money and purchase the product, they feel maliciously envious and have a higher WTP for other products.

Recently, the free space optical (FSO) communications have been widely studied as an alternative for large capacity communications and its possible implementation in satellite and terrestrial laser links. In satellite communications, clouds can strongly attenuate the laser signal that would lead to high bit-error rates or temporal unavailability of the link. To overcome the cloud coverage effects, often site diversity technique is implemented. When using multiple ground stations though, simplified optical system is required to allow the usage of more flexible approaches. In terrestrial laser communications, several methods for optical system simplification by using a multimode fiber (MMF) have been proposed.

We investigate the detection of a single-photon source using highly efficient superconducting nanowire single-photon detectors (SNSPDs) at telecom wavelengths. Both the single-photon source and the detectors are characterized in detail. At a pump power of 100 mW (400 mW), the measured coincidence counts can achieve 400 kcps (1.17 Mcps), which is the highest ever reported at telecom wavelengths to the best of our knowledge. The multi-pair contributions, the experimental and theoretical second order coherence functions, and the saturation property of SNSPD are analyzed in detail. The experimental data and theoretical analysis should be useful for the future experiments to detect ultra-bright down-conversion sources with high-efficiency detectors.

Two novel ruthenium sensitizers with a hexylthiophene-modified terpyridine ligand (TUS-35 and TUS-36) were synthesized to improve the molar absorptivity of the previously reported ruthenium sensitizer (TBA)[Ru{4'-(3,4-dicarboxyphenyl)-4,4″-dicarboxyterpyridine}(NCS)3], TBA = tetrabutylammonium (TUS-21). A relatively strong absorption appeared at ∼380 nm, and the molar absorption coefficient at the metal-to-ligand charge transfer (MLCT) band decreased in TUS-35 by introducing a 2-hexylthiophene unit to the 5-position of the terpyridine-derived ligand. For comparison, a relatively strong absorption was observed at ∼350 nm without decreasing the molar absorption coefficient at the MLCT band in TUS-36 by introducing a 2-hexylthiophene unit to the 4-position of the terpyridine-derived ligand. On the other hand, the energy levels of the highest occupied molecular orbitals and the lowest unoccupied molecular orbitals of these two sensitizers were found to be almost equal to those of TUS-21. The adsorption behavior of TUS-35 and TUS-36 was similar to that of (TBA)[Ru{4'-(3,4-dicarboxyphenyl)terpyridine}(NCS)3] (TUS-20), which binds to the TiO2 surface by using the 3,4-dicarboxyphenly unit, rather than that of TUS-21, which adsorbs to the TiO2 photoelectrode using one of the carboxyl groups at the terminal pyridines of the terpyridine-derived ligand. Therefore, TUS-35 and TUS-36 are considered to bind to the TiO2 surface by using the 3,4-dicarboxyphenly unit just like TUS-20. The dye-sensitized solar cells (DSCs) with TUS-35 and TUS-36 showed a relatively lower conversion efficiency (6.4% and 5.7%, respectively) compared to the DSC with TUS-21 (10.2%). Open-circuit photovoltage decay and electrochemical impedance spectroscopy measurements revealed that the promoted charge recombination and/or charge transfer of the injected electrons in the TiO2 photoelectrode is a main reason for the inferior performances of TUS-35 and TUS-36.

Second-generation antisense oligonucleotides (ASOs) demonstrate excellent biological stability and in vitro/in vivo potency, and thus are considered to be attractive candidates for drugs to treat various diseases. A pharmacokinetic-pharmacodynamic (PK-PD) model of ASOs is desired for the design of appropriate PK and pharmacological studies. The objective of this study was to develop a PK-PD model to accurately simulate hepatic ASO concentration and its efficacy from plasma ASO concentration. After single subcutaneous administration of an ASO targeting hepatic apolipoprotein B (Apo-B) mRNA to mice, the ASO was absorbed rapidly and showed biphasic decline with time from the plasma and liver (t1/2: 1-3 and 81-183 h, Tmax: 0.25-0.50 and 4-8 h). After administration, hepatic Apo-B mRNA and plasma total cholesterol began decreasing at 4-8 and 8-24 h, and their Tmax values were observed at 24-72 and 72 h. To develop the PK-PD model based on the mechanisms of ASOs, we described the plasma and hepatic ASO concentration with linear two-compartment models. In addition, we inserted two indirect response models for mRNA and plasma total cholesterol. Model predictions from plasma ASO concentration gave excellent fits to the observed values of hepatic ASO concentration, Apo-B mRNA and plasma total cholesterol after single or multiple subcutaneous administrations. Our PK-PD model could accurately predict hepatic ASO concentrations and their efficacies from plasma ASO concentrations. This PK-PD model could be a useful tool for suggesting PK and pharmacological study protocols for various liver-targeted second-generation ASOs.

Polymer-based solar cells have made rapid progress in the last decade and are currently attracting a great deal of attention as a next-generation solar cell. Very recently, they have shown a power conversion efficiency (PCE) of more than 10%, which is comparable to that reported for amorphous silicon solar cells. However, it is still required to improve the photovoltaic performance furthermore for practical applications. In this talk, I will demonstrate ternary blend polymer solar cells, which are a new approach to improving the photocurrent generation. We have recently developed ternary blend polymer solar cells based on a wide-bandgap polymer, poly(3-hexylthiophene) (P3HT), a fullerene derivative (PCBM), and a near-IR dye molecule such as a silicon phthalocyanine derivative (SiPc). Such near-IR dye addition can easily expand the light-harvesting wavelength range up to the near-IR region, and hence can boost the photocurrent furthermore. I will demonstrate how molecular design of near-IR dye molecules can control the location in ternary blend solar cells to improve the photocurrent generation effectively. We also have fabricated ternary blend polymer solar cells based on a wide-bandgap polymer, a low-bandgap polymer, and PCBM. This two-donor polymer blend can also expand the light-harvesting wavelength and hence can boost the photocurrent effectively. Efficient exciton harvesting and charge collection can be designed by combining a wide-bandgap crystalline polymer and a low-bandgap amorphous polymer.

Multiparticle interference is a fundamental phenomenon in the study of quantum mechanics.It was discovered in a recent experiment [Ra, Y.-S. et al, Proc. Natl Acad. Sci. USA \textbf{110}, 1227(2013)] that spectrally uncorrelated biphotons exhibited a nonmonotonic quantum-to-classical transition in a four-photon Hong-Ou-Mandel (HOM) interference. In this work, we consider the same scheme with spectrally correlated photons.By theoretical calculation and numerical simulation, we found the transition not only can be nonmonotonic with negative-correlated or uncorrelated biphotons, but also can be monotonic with positive-correlated biphotons. The fundamental reason for this difference is that the HOM-type multi-photon interference is a differential-frequency interference. Our study may shed new light on understanding the role of frequency entanglement in multi-photon behavior., Comment: 8 pages, 2 figures

Two novel ruthenium sensitizers having multiple carboxyl groups ((TBA)[Ru{4′-(3,4-dicarboxyphenyl)-4,4″-dicarboxyterpyridine}(NCS)3] (TUS-21) and (TBA)[Ru{4′-(3-carboxyphenyl)-4,4″-dicarboxyterpyridine}(NCS)3] (TUS-37); TBA = tetrabutylammonium) have been synthesized as improved model sensitizers for the previously reported ruthenium sensitizer TUS-20 ((TBA)[Ru{4′-(3,4-dicarboxyphenyl)terpyridine}(NCS)3]). The absorption maxima of two MLCT bands and the absorption onsets of TUS-21 and TUS-37 were shifted to longer wavelengths of about 30 nm in comparison to those of TUS-20 by introducing a carboxyl group to the each terminal pyridine ring of the terpyridine ligand. TUS-21 and TUS-37 showed quite similar adsorption behaviors to the TiO2 surface, and this adsorption behavior was found to be different from that of TUS-20. ATR-IR measurements revealed that TUS-21 and TUS-37 bind to the TiO2 surface by using two carboxyl groups at the 3-position of the phenyl ring and at one of the terminal pyridine rings of t...

Self-assembled octadecyltrichlorosilane ((OTS), CH3(CH2)17SiCl3) layers on hydroxyl-terminated silicon oxide (SiO2) were prepared. The monolayers were characterized with atomic force microscopy (AFM) and contact angle measurements; their conformation was studied before, during, and after contact with a polymer (either PDMS or PTFE) surface using the vibrational sum frequency spectroscopy (VSFS) technique. During contact, the effect of pressure was studied for both polymer surfaces, but in the case of PTFE, the effect of shear rate on the contact was simultaneously studied. The VSFS response of the monolayers with pressure was almost entirely due to changes in the real area of contact with the polymer and therefore the Fresnel factors, whereas sliding caused disorder in the previously all-trans monolayer, as evidenced by a significant increase in the population of gauche defects.

Quantum communication and quantum cryptography are expected to enhance the transmission rate and the security (confidentiality of data transmission), respectively. We study a new scheme which can potentially bridge an intermediate region covered by these two schemes, which is referred to as quantum photonic network. The basic framework is information theoretically secure communications in a free space optical (FSO) wiretap channel, in which an eavesdropper has physically limited access to the main channel between the legitimate sender and receiver. We first review a theoretical framework to quantify the optimal balance of the transmission efficiency and the security level under power constraint and at finite code length. We then present experimental results on channel characterization based on 10 MHz on–off keying transmission in a 7.8 km terrestrial FSO wiretap channel. This article is part of the themed issue ‘Quantum technology for the 21st century’.

In single-wafer cleaning of semiconductor chips and flat panel displays, various cleaning methods tailored to the process, such as two-fluid spray cleaning, high-pressure jet spray cleaning, ultrasonic cleaning spray cleaning, and scrub cleaning have been proposed and put to practical use. In this study, Polyethylene Latex (PSL) particles 0.2 µm in diameter and 1 µm in diameter were electro-sprayed on the SiO2 The soil samples, and then cleaning efficiency were measured using two types of ultrasonic sprayers with frequencies of 1 MHz and 3 MHz confirmed. The soil samples are controlled for adhesion by deforming the PSL particles by heating the silicon wafer from 300K to 425K. From the experimental results, it was found that the is determined by factors other than the conventionally reported radiation flow in PSL particles. Figure 1

The purpose of this study was to clarify the acute effects of a single session of stretching exercises on vascular endothelial function and peripheral circulation in patients with acute myocardial infarction. This study evaluated 32 patients (mean age, 66 ± 9 years) who received phase I cardiac rehabilitation after acute myocardial infarction. Five types of stretching exercises were performed on the floor: wrist dorsiflexion, close-legged trunk flexion, open-legged trunk flexion, open-legged lateral trunk bending, and cross-legged trunk flexion. Each exercise entailed a 30-second stretching followed by a 30-second relaxation, and was repeated twice. Low- and high-frequency components (LF and HF) of heart rate variability (LF, 0.04-0.15 Hz; HF, 0.15-0.40 Hz) were analyzed, and HF and LF/HF were used as indices of parasympathetic and sympathetic nervous activities, respectively. Reactive hyperemia peripheral arterial tonometry (RH-PAT) index was measured and used as a parameter for vascular endothelial function. Transcutaneous oxygen pressure (tcPO2) on the right foot and chest was also measured, and the Foot-tcPO2/Chest-tcPO2 ratio was used as a parameter for peripheral circulation. The HF, RH-PAT index, and Foot-tcPO2/Chest-tcPO2 ratio were significantly higher after the exercises than before (P < 0.05, P < 0.01, and P < 0.05, respectively). There was no significant difference in the LF/HF ratio measured before and after stretching exercises. These findings demonstrate that stretching exercises improve vascular endothelial function and peripheral circulation in patients with acute myocardial infarction.

The NOON state, and its experimental approximation the Holland-Burnett state, have important applications in phase sensing measurement with enhanced sensitivity. However, most of the previous Holland-Burnett state interference (HBSI) experiments only investigated the area of the interference pattern in the region immediately around zero optical path length difference, while the full HBSI pattern over a wide range of optical path length differences has not yet been well explored. In this work, we experimentally and theoretically demonstrate up to six-photon HBSI and study the properties of the interference patterns over a wide range of optical path length differences. It was found that the shape, the coherence time and the visibility of the interference patterns were strongly dependent on the detection schemes. This work paves the way for applications which are based on the envelope of the HBSI pattern, such as quantum spectroscopy and quantum metrology.

Japanese animation, called anime, has long been regarded as a niche culture reserved for ‘nerds’ (otaku) in Japan. The word otaku refers to individuals who spend most of their time alone at home watching anime, reading comics (manga) and/or playing video games. However, in recent years, otaku, or anime viewers, have changed their behavioral patterns, resulting in a new transcultural movement. That peculiar phenomenon is known as anime pilgrimage, which involves traveling to locations that resemble particular scenes in anime pieces, even though the locations themselves may be ordinary places. Research on ordinary tourism has focused mainly on destination attributes as determinants of visit intention/destination loyalty. Research on film tourism places additional emphasis on the role of film involvement. We focus here on social influences. The results of structured regression analyses show that our new models were superior to previous models that omitted investigation of social influences. Furthermore, the results show that though, during the pre-trip period “within home”, anime nerds may expect that they will interact primarily with other nerds, they enjoy interactions with the local people while traveling. Such transcultural experiences result in higher destination loyalty during the post-trip period “beyond home”.

We present experimental data on message transmission in a free-space optical (FSO) link at an eye-safe wavelength, using a testbed consisting of one sender and two receiver terminals, where the latter two are a legitimate receiver and an eavesdropper. The testbed allows us to emulate a typical scenario of physical-layer (PHY) security such as satellite-to-ground laser communications. We estimate information-theoretic metrics including secrecy rate, secrecy outage probability, and expected code lengths for given secrecy criteria based on observed channel statistics. We then discuss operation principles of secure message transmission under realistic fading conditions, and provide a guideline on a multi-layer security architecture by combining PHY security and upper-layer (algorithmic) security., Comment: 16 pages, 8 figures