Weak antilocalization in Cd3As2 thin films

Recently, it has been theoretically predicted that Cd3As2 is a three dimensional Dirac material, a new topological phase discovered after topological insulators, which exhibits a linear energy dispersion in the bulk with massless Dirac fermions. Here, we report on the low-temperature magnetoresistance measurements on a ~50nm-thick Cd3As2 film. The weak antilocalization under perpendicular magnetic field is discussed based on the two-dimensional Hikami-Larkin-Nagaoka (HLN) theory. The electron-electron interaction is addressed as the source of the dephasing based on the temperature-dependent scaling behavior. The weak antilocalization can be also observed while the magnetic field is parallel to the electric field due to the strong interaction between the different conductance channels in this quasi-two-dimensional film

Absence of metallicity and bias-dependent resistivity in low-carrier-density EuCd2As2

EuCd2As2 was theoretically predicted to be a minimal model of Weyl semimetals with a single pair of Weyl points in the ferromagnet state. However, the heavily p-doped EuCd2As2 crystals in previous experiments prevent direct identification of the semimetal hypothesis. Here we present a comprehensive magneto-transport study of high-quality EuCd2As2 crystals with ultralow bulk carrier density (10^13 cm-3). In contrast to the general expectation of a Weyl semimetal phase, EuCd2As2 shows insulating behavior in both antiferromagnetic and ferromagnetic states as well as surface-dominated conduction from band bending. Moreover, the application of a dc bias current can dramatically modulate the resistance by over one order of magnitude, and induce a periodic resistance oscillation due to the geometric resonance. Such nonlinear transport results from the highly nonequilibrium state induced by electrical field near the band edge. Our results suggest an insulating phase in EuCd2As2 and put a strong constraint on the underlying mechanism of anomalous transport properties in this system.Comment: 13 pages, 4 figure

Superconductivity in trilayer nickelate La4Ni3O10 under pressure

Nickelates gained a great deal of attention due to their similar crystal and electronic structures of cuprates over the past few decades. Recently, superconductivity with transition temperature exceeding liquid-nitrogen temperature is discovered in La3Ni2O7, which belong to the Ruddlesden-Popper (RP) phases Lan+1NinO3n+1 with n = 2. In this work, we go further and find pressure-induced superconductivity in another RP phase La4Ni3O10 (n = 3) single crystals. Our angle-resolved photoemission spectroscopy (ARPES) experiment suggest that the electronic structure of La4Ni3O10 is very similar to that of La3Ni2O7. We find that the density-wave like anomaly in resistivity is progressively suppressed with increasing pressure. A typical phase diagram is obtained with the maximum Tc of 21 Kelvin. Our study sheds light on the exploration of unconventional superconductivity in nickelates.Comment: 16 pages, 5 figure

A noninvasive model for chronic kidney disease screening and common pathological type identification from retinal images

Chronic kidney disease (CKD) is a global health challenge, but invasive renal biopsies, the gold standard for diagnosis and prognosis, are often clinically constrained. To address this, we developed the kidney intelligent diagnosis system (KIDS), a noninvasive model for renal biopsy prediction using 13,144 retinal images from 6773 participants. The KIDS achieves an area under the receiver operating characteristic curve (AUC) of 0.839–0.993 for CKD screening and accurately identifies the five most common pathological types (AUC: 0.790–0.932) in a multicenter and multi-ethnic validation, outperforming nephrologists by 26.98% in accuracy. Additionally, the KIDS further predicts disease progression based on pathological classification. Given its flexible strategy, the KIDS can be adapted to local conditions to provide a tailored tool for patients. This noninvasive model has the potential to improve CKD clinical management, particularly for those who are ineligible for biopsies

A plastic optic fiber sensor with temperature compensation for glucose concentration measurement

An optical fiber sensor based on a gradually hot-pressed flatted plastic optical fiber (GPF) and F-P interference structure is proposed to eliminate the effect of ambient temperature drift in the detection of glucose concentration. The sensing characteristics of the prepared sensing head were studied at various glucose concentrations and ambient temperatures. Based on the differential sensitivity of GPF and F-P interference film to glucose concentration and temperature, temperature-compensated glucose concentration sensing monitoring was obtained by the sensitivity matrix equation, where the peak wavelength of interference peak and transmitted light intensity were used as information carriers. The results show that the proposed plastic optical fiber sensor can provide the monitoring of glucose sample concentrations ranging from 0 to 500mg.ml-1, and the effect of ambient temperature drift is eliminated to make it more useful. Because of its simple structure, high repeatability, easy integration with the chip, and ability to eliminate the effect of temperature drift, the sensor has potential applications in biochemistry, medical diagnosis, and environmental monitoring.</jats:p

Dynamic Wheel Load Measurements by Optical Fiber Interferometry

This study proposes a Fabry&ndash;Perot interferometric system and an associated evaluation method for measuring the weight of moving trains. An optical fiber sensor, comprising a sensing fiber and a supporting structure, is securely bonded to the rail foot. As a train traverses the track, the resulting localized bending induces a change in the sensing fiber&rsquo;s length, which manifests as a quantifiable phase shift in the interference signal. We developed a physical&ndash;mathematical model, based on three Gaussian functions, to describe the temporal change in sensing fiber length caused by the passage of a single bogie. This model enables the determination of a proportionality constant to accurately convert the measured phase change into train weight. Model validation was performed using a train set, including a locomotive and four variably loaded wagons, traveling at 15.47 km/h. This system offers a novel and effective approach for real-time train weight monitoring