The LAMOST-Kepler (LK-) project was initiated to use the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) to make spectroscopic follow-up observations for the targets in the field of the Kepler mission. The Kepler field is divided into 14 subfields that are adapted to the LAMOST circular field with a diameter of 5°. During the regular survey phase of LAMOST, the LK-project took data from 2012 June to 2017 June and covered all 14 subfields at least twice. In particular, we describe in this paper the second Data Release of the LK-project, including all spectra acquired through 2015 May–2017 June together with the first round observations of the LK-project from 2012 June to 2014 September. The LK-project now counts 227,870 spectra of 156,390 stars, among which we have derived atmospheric parameters ( , T _eff, and [Fe/H]) and heliocentric radial velocity for 173,971 spectra of 126,172 stars. These parameters were obtained with the most recent version of the LAMOST Stellar Parameter Pipeline v 2.9.7. Nearly one half, namely 76,283 targets, are observed both by the LAMOST and Kepler telescopes. These spectra, establishing a large spectroscopy library, will be useful for the entire astronomical community, particularly for planetary science and stellar variability on Kepler targets.

Background and Purpose—: Distribution patterns of iron deposition in deep gray matter and their association with clinical characteristics in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) remain unclear. We aimed to evaluate iron deposition in deep gray matter in patients with CADASIL using 7.0-T susceptibility-weighted imaging and mapping and to explore its correlations with clinical characteristics. Methods—: Thirty-nine patients with CADASIL, confirmed via genetic analysis or skin biopsy, were enrolled. We examined patients using the Mini-Mental State Examination, modified Rankin Scale, and brain 7.0-T magnetic resonance imaging and obtained magnetic resonance imaging lesion loads, small vessel disease scores, and susceptibility mapping. The following regions of interest were selected: caudate nucleus, putamen, globus pallidus, thalamus, substantia nigra, and red nucleus. The quantitative differences in the susceptibility of deep gray matter between the CADASIL and control groups and the correlations between deep gray matter susceptibility and clinical characteristics were identified. Results—: Compared with the control group, the CADASIL group showed significantly increased susceptibility of caudate nucleus, putamen, thalamus, substantia nigra, and red nucleus. The susceptibility of deep gray matter in basal ganglia region, including caudate nucleus, putamen, and thalamus, significantly increased with age or disease duration and positively correlated with small vessel disease scores in patients with CADASIL. Moreover, the susceptibility of thalamus positively correlated with modified Rankin Scale scores after adjusting for age and disease duration and that of putamen negatively correlated with Mini-Mental State Examination scores in patients with CADASIL after adjusting for age. Conclusions—: Our findings indicate an association between abnormal iron deposition in deep gray matter of patients with CADASIL and their clinical characteristics. Therefore, excess iron deposition in deep gray matter, as indicated by 7.0-T susceptibility-weighted imaging and mapping, might not only be a novel magnetic resonance imaging feature but also a potential biomarker for CADASIL severity.

Giant magneto-resistive (GMR)-superconducting mixed magnetic sensors are expected to be widely used because of their excellent sensitivity, stability, band characteristics, and low cost. If a tunnel magnetoresistance (TMR)-superconducting mixed magnetic sensor is prepared using a higher sensitivity and lower power TMR instead of GMR, the performance of the device will be further improved. We have fabricated a TMR-superconducting mixed sensor by a bonding process, and the feasibility was verified. The sensitivity was 21 times higher than that of the TMR device alone, reaching 18.1%/Oe. The noise level reached 6.6 pT/Hz ^1/2 at 77 K. At the same time, the influence of different constriction width of the superconducting magnetic flux concentrator on the device performance was compared at 4.5-77 K.

A novel architecture for the superconductor/magnetoresistance (MR) composite sensor with vertical magnetic flux concentrators (MFCs) was studied theoretically and experimentally in this paper, to enhance the sensor’s sensitivity and resolution. The three-dimensional finite element method (FEM) of the superconducting flux transformation amplifier (SFTA), characterized by the E-J power law, was firstly established to design and optimize the structure of SFTA with MFCs. Then the influence of the key size of MFCs on the gain factor of SFTA was discussed. Finally, a superconductor/TMR composite sensor with specific-sized MFCs was designed and manufactured. Experimental results showed that the sensitivity was increased by 1.84 times, and the magnetic field resolution was improved from 81 pT/Hz ^0.5 to 49 pT/Hz ^0.5 by about 1.63 times after setting vertical MFCs, which all accorded with the FEM simulation prediction result of 1.75 times. The work in this paper contributes to the development of high-performance superconductor/MR composite sensors.