Training Process of Unsupervised Learning Architecture for Gravity Spy Dataset

Transient noise appearing in the data from gravitational-wave detectors frequently causes problems, such as instability of the detectors and overlapping or mimicking gravitational-wave signals. Because transient noise is considered to be associated with the environment and instrument, its classification would help to understand its origin and improve the detector's performance. In a previous study, an architecture for classifying transient noise using a time–frequency 2D image (spectrogram) is proposed, which uses unsupervised deep learning combined with variational autoencoder and invariant information clustering. The proposed unsupervised-learning architecture is applied to the Gravity Spy dataset, which consists of Advanced Laser Interferometer Gravitational-Wave Observatory (Advanced LIGO) transient noises with their associated metadata to discuss the potential for online or offline data analysis. In this study, focused on the Gravity Spy dataset, the training process of unsupervised-learning architecture of the previous study is examined and reported.     

Diastereoisomerism of thiol complexes of arsenic acids and pseudoasymmetry of arsenic: a 1H and 13C NMR study

Diastereoisomeric complexes of methylphenylarsinic acid and (L)-glutathione could be partially separated by HPLC, but the separated compounds rapidly racemized, presumably by pyramidal inversion at the arsenic atom. Hydrolysis of the diastereoisomeric complexes yielded methylphenylarsinous acid as a pair of enantiomers revealed by a 1H NMR study with an asymmetric lanthanide shift reagent. Methylphenylarsinous acid was also synthesized as an enantiomeric pair, shown by an asymmetric shift reagent experiment, by the hydrolysis of iodomethylphenylarsine. 1H and 13C NMR spectroscopy were used to demonstrate that complexing of phenylarsonic acid with (R,S)-3-mercapto-1,2-propanediol and with (R,S)-1-mercapto-2-propanol yielded, in each case, a pair of enantiomers, PhAs[(R)-ligand)]2, PhAs[(S)-ligand)]2, in which the homomorphic ligands were diastereotopic, and a pair of diastereoisomers, PhAs[(R)-ligand][(S)-ligand], which differed from each other in the configuration about the pseudoasymmetric arsenic atom.     

Nanosecond rapid freezing of liquid benzene under shock compression studied by time-resolved coherent anti-Stokes Raman spectroscopy

Nanosecond time-resolved coherent anti-Stokes Raman spectroscopy is used to investigate the shock-induced liquid-solid phase transition and crystallization of liquid benzene. Temporal evolution of the Raman shift of the ring-breathing and C-H stretching modes is investigated. A metastable supercompressed state and a liquid-solid phase transition are observed under shock compression. Time-resolved Raman spectra reveal that the liquid state is initially a metastable state and rapidly transforms to the solid state within 25 ns under shock compression at 4.2 GPa.     

Single-shot two-dimensional spectral interferometry for ultrafast laser-produced plasmas

Coherent white light was used as a light source for spectral interferometry of ultrafast laser-produced plasmas. Using a narrowband filter, two-dimensional images of field ionization in helium were obtained with a 14 fs time resolution.     

Anisotropic x-ray emission from heliumlike Fe24+ ions aligned by resonant coherent excitation with a periodic crystal potential

We have measured deexcitation x rays emitted from the resonant coherently excited 2(1)P(1) state of heliumlike Fe24+ ions of 423 MeV/amu, planar channeling through a Si crystal. Large anisotropy in the angular distribution of deexcitation x-ray emission is observed: the x-ray emission in the direction parallel to the channeling plane is favored by a factor of 2 compared to the perpendicular direction. This anisotropy originates from the direction of the periodic crystal field, which populates specific m states in resonant coherent excitation and aligns the excited states.     

A Novel DNA Helical Wire Containing HgII‐Mediated T:T and T:G Pairs

Numerous applications of metal‐mediated base pairs (metallo‐base‐pairs) to nucleic acid based nanodevices and genetic code expansion have been extensively studied. Many of these metallo‐base‐pairs are formed in DNA and RNA duplexes containing Watson–Crick base pairs. Recently, a crystal structure of a metal–DNA nanowire with an uninterrupted one‐dimensional silver array was reported. We now report the crystal structure of a novel DNA helical wire containing Hg^II‐mediated T:T and T:G base pairs and water‐mediated C:C base pairs. The Hg‐DNA wire does not contain any Watson–Crick base pairs. Crystals of the Hg‐DNA wire, which is the first DNA wire structure driven by Hg^II ions, were obtained by mixing the short oligonucleotide d(TTTGC) and Hg^II ions. This study demonstrates the potential of metallo‐DNA to form various structural components that can be used for functional nanodevices.     

Controlling the Emergence and Shift Direction of Mechanochromic Luminescence Color of a Pyridine‐Terminated Compound

In this study, mechanochromic luminescence was induced in a complex of mechano‐inactive compounds. Dye/acid complexes containing the same π‐conjugated backbones were prepared. While the luminophore showed blue and red shifts in photoluminescence spectra when combined with different acids by grinding, it exhibited slight mechanoresponsiveness itself. Also, compounds with similar molecular backbones to the dye/acid complex were synthesized to clarify the color change mechanism. The compounds showed both blue and red shifts in photoluminescence and diffuse reflectance spectra upon grinding, indicating that mechanochromic luminescence in the hydrogen‐bonded complex is like its monomeric analogue and that aggregation structure plays an important role in mechanoresponsive behavior rather than the π‐conjugated structure. It was shown that a color change can be mechanically induced by imitating the solid‐state aggregation structure of other mechanoresponsive compounds without synthetic modification.     

Modular-value-based metrology with spin coherent pointers

We discuss an optimal modular-value-based measurement with a spin coherent pointer: A quantum system is exposed to a field whose strength is to be estimated through its modular value. We evaluate the quantum Fisher information as a figure of merit. We found that the modular-value-based measurement can reach the same ultimate precision limit of the estimation as those of measurements without postselections. The quantum Fisher information can be increased when the dimension of the pointer state increases. We also consider the pointer under a phase-flip error. Our study should motivate researchers to apply the modular-value-based measurements for quantum metrology.     

Synthesis of the cyclohexene segment of portimine

The synthesis of the cyclohexene segment of portimine, a marine cytotoxin from the dinoflagellate Vulcanodinium rugosum, was achieved. The route includes an acylation/aldol reaction from 3-ethoxycyclohex-2-enone to create the C3 center, the 1,4-addition of a vinyl group at C16, the diastereoselective dihydroxylation of the vinyl group to generate the C15 center, a vinylation/dehydration sequence to set up the diene moiety, and stepwise installation of the amino-group-substituted C1 unit.     

冷鲜猪肉的三维荧光光谱特征研究

利用三维荧光光谱技术,研究了冷鲜猪肉三维荧光光谱特征,主要探讨了不同温度存储条件下冷鲜猪肉荧光峰的位置和荧光峰所处区域内荧光强度平均值随存储时间变化的规律,并初步判断了荧光物质的种类,为实现基于三维荧光光谱技术快速、无损检测冷鲜猪肉新鲜度奠定了理论基础。实验结果表明,不同温度存储条件下样本的三维荧光光谱图中均含有2个明显的荧光峰（Peak A和Peak B）,它们所在位置的激发波长（λ_ex）/发射波长（λ_em）范围分别为：λ_ex/λ_em约为250～310 nm/300～400 nm和约为300～450 nm/400～550 nm。其中,Peak A为类蛋白荧光,Peak B为脂质氧化产物荧光。此外,实验还发现,两个荧光峰在各自所处区域内荧光强度的平均值随存储时间变化的趋势不受存储温度影响,均是Peak A在λ_ex/λ_em=250～310 nm/300～400 nm区域内荧光强度的平均值（I_A）逐渐下降,Peak B在λ_ex/λ_em=300～450 nm/400～550 nm区域内荧光强度的平均值（I_B）逐渐上升。但I_A和I_B的变化速率受存储温度影响,冷藏条件下比室温条件下变化慢。