Weak signal extraction enabled by deep neural network denoising of diffraction data.

The removal or cancellation of noise has wide-spread applications in imaging and acoustics. In applications in everyday life, such as image restoration, denoising may even include generative aspects, which are unfaithful to the ground truth. For scientific use, however, denoising must reproduce the ground truth accurately. Denoising scientific data is further challenged by unknown noise profiles. In fact, such data will often include noise from multiple distinct sources, which substantially reduces the applicability of simulation-based approaches. Here we show how scientific data can be denoised by using a deep convolutional neural network such that weak signals appear with quantitative accuracy. In particular, we study X-ray diffraction and resonant X-ray scattering data recorded on crystalline materials. We demonstrate that weak signals stemming from charge ordering, insignificant in the noisy data, become visible and accurate in the denoised data. This success is enabled by supervised training of a deep neural network with pairs of measured low- and high-noise data. We additionally show that using artificial noise does not yield such quantitatively accurate results. Our approach thus illustrates a practical strategy for noise filtering that can be applied to challenging acquisition problems.

Resonant inelastic soft x-ray scattering on LaPt2Si2.

X-ray absorption and resonant inelastic x-ray scattering spectra of LaPt2Si2single crystal at the Si 2pand La 4dedges are presented. The data are interpreted in terms of density functional theory, showing that the Si spectra can be described in terms of Sisanddlocal partial density of states (LPDOS), and the La spectra are due to quasi-atomic local 4fexcitations. Calculations show that Ptd-LPDOS dominates the occupied states, and a sharp localized Lafstate is found in the unoccupied states, in line with the observations.

Charge order lock-in by electron-phonon coupling in La1.675Eu0.2Sr0.125CuO4.

Charge order is universal to all hole-doped cuprates. Yet, the driving interactions remain an unsolved problem. Electron-electron interaction is widely believed to be essential, whereas the role of electron-phonon interaction is unclear. We report an ultrahigh-resolution resonant inelastic x-ray scattering (RIXS) study of the in-plane bond-stretching phonon mode in stripe-ordered cuprate La1.675Eu0.2Sr0.125CuO4 Phonon softening and lifetime shortening are found around the charge ordering wave vector. In addition to these self-energy effects, the electron-phonon coupling is probed by its proportionality to the RIXS cross section. We find an enhancement of the electron-phonon coupling around the charge-stripe ordering wave vector upon cooling into the low-temperature tetragonal structure phase. These results suggest that, in addition to electronic correlations, electron-phonon coupling contributes substantially to the emergence of long-range charge-stripe order in cuprates.

Polytypism and superconductivity in the NbS2 system.

We report on the phase formation and the superconducting properties in the NbS2 system. Specifically, we have performed a series of standardized solid-state syntheses in this system, which allow us to establish a comprehensive synthesis map for the formation of the two polytypes 2H-NbS2 and 3R-NbS2, respectively. We show that the identification of two polytypes by means of X-ray diffraction is not always unambiguous. Our physical property measurements on a phase-pure sample of 3R-NbS2, on a phase-pure sample of 2H-NbS2, and a mixed phase sample confirm earlier reports that 2H-NbS2 is a bulk superconductor and that 3R-NbS2 is not a superconductor above T = 1.75 K. Our results clearly show that specific heat measurements, as true bulk measurements, are crucial for the identification of superconducting materials in this and related systems. Our results indicate that for the investigation of van der Waals materials great care has to be taken on choosing the synthesis conditions for obtaining phase pure samples.

Effects of a 12-week program of Tai Chi exercise on the kidney disease quality of life and physical functioning of patients with end-stage renal disease on hemodialysis.

BACKGROUND: Previous studies have shown that exercise training in patients with end-stage renal disease could improve their physical functioning and quality of life. Nevertheless, few studies have evaluated the effects of Tai Chi exercise in patients on hemodialysis. OBJECTIVE: To investigate the effects of a Tai Chi exercise intervention on the quality of life and physical functioning in end-stage renal disease patients on hemodialysis. DESIGN: A pre-post experimental design. SETTING: Patients, aged 20 years or older, on hemodialysis recruited from the hemodialysis unit at a medical center in central Taiwan were assigned, based on their own preference, to either a control group (n=25) or an intervention group (n=21). INTERVENTION: A weekly one-hour short-form Yang style Tai Chi session for a total of 12 weeks. MAIN OUTCOME MEASURES: Physical functioning and Kidney Disease Quality of Life (KDQOL) at the baseline and at the end of the intervention. RESULTS: The least square means of repetition of sit-to-stand cycles in one minute (STS-60), 6-min walk test, and gait speed test were significantly improved in the intervention group. In addition, the least square means of the five different dimensions of the KDQOL were all significantly higher in the intervention group, except the SF-12 physical health score. CONCLUSIONS: Improvements in the kidney disease quality of life and physical functioning were observed in Taiwanese patients on hemodialysis with a 12-week Tai Chi exercise intervention.

On-board sample cleaver.

An on-board sample cleaver has been developed in order to cleave small and hard-to-cleave samples. To acquire good cleaves from rigid samples the alignment of the cleaving blade with respect to the internal crystallographic planes is crucial. To have the opportunity to mount the sample and align it to the blade ex situ has many advantages. The design presented has allowed us to cleave very tiny and rigid samples, e.g., the high-temperature superconductor La((2-x))Sr(x)CuO(4). Further, in this design the sample and the cleaver will have the same temperature, allowing us to cleave and keep the sample at low temperature. This is a big advantage over prior cleaver systems. As a result, better surfaces and alignments can be realized, which considerably simplifies and improves the experiments.