Jun Lu

Bio: Jun Lu is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Medicine & Materials science. The author has an hindex of 135, co-authored 1526 publications receiving 99767 citations. Previous affiliations of Jun Lu include Drexel University & Argonne National Laboratory.

The 77-K Stress and Strain Dependence of the Critical Current of YBCO Coated Conductors and Lap Joints

Abstract: The electromechanical performance of commercially available YBCO high-temperature superconductor (HTS) is characterized in support of the 32T all-superconducting magnet program at the National High Magnetic Field Laboratory. Accurate characterization of the HTS coated conductors mechanical properties are essential for the aggressive high-field magnet design. Here, we report the 77-K stress-strain behavior of a series of conductors with varying thickness coatings of copper. The electromechanical performance of the conductors is determined in tests to measure the critical current as a function of applied axial strain, at 77-K in self field. Available conductor lengths necessitate a magnet design with soldered lap joints and the subsequent evaluation the lap joint performance reported here. Reports of low transverse strength and conductor delamination due transverse ( c-axis) tensile stress prompted tests to measure the conductors' electrical performance in the presence of transverse stress that are also reported.

Brainstem Circuitry Regulating Phasic Activation of Trigeminal Motoneurons during REM Sleep

Abstract: Background Rapid eye movement sleep (REMS) is characterized by activation of the cortical and hippocampal electroencephalogram (EEG) and atonia of non-respiratory muscles with superimposed phasic activity or twitching, particularly of cranial muscles such as those of the eye, tongue, face and jaw. While phasic activity is a characteristic feature of REMS, the neural substrates driving this activity remain unresolved. Here we investigated the neural circuits underlying masseter (jaw) phasic activity during REMS. The trigeminal motor nucleus (Mo5), which controls masseter motor function, receives glutamatergic inputs mainly from the parvocellular reticular formation (PCRt), but also from the adjacent paramedian reticular area (PMnR). On the other hand, the Mo5 and PCRt do not receive direct input from the sublaterodorsal (SLD) nucleus, a brainstem region critical for REMS atonia of postural muscles. We hypothesized that the PCRt-PMnR, but not the SLD, regulates masseter phasic activity during REMS.

Advanced cyclopentadienyl precursors for atomic layer deposition of ZrO2 thin films

Abstract: ZrO2 thin films were grown onto silicon (100) substrates by atomic layer deposition (ALD) using novel cyclopentadienyl-type precursors, namely (CpMe)2ZrMe2 and (CpMe)2Zr(OMe)Me (Cp = cyclopentadienyl, C5H5) together with ozone as the oxygen source. Growth characteristics were studied in the temperature range of 250 to 500 °C. An ALD-type self-limiting growth mode was verified for both processes at 350 °C where highly conformal films were deposited onto high aspect ratio trenches. Signs of thermal decomposition were not observed at or below 400 °C, a temperature considerably exceeding the thermal decomposition temperature of the Zr-alkylamides. Processing parameters were optimised at 350 °C, where deposition rates of 0.55 and 0.65 A cycle−1 were obtained for (CpMe)2ZrMe2/O3 and (CpMe)2Zr(OMe)Me/O3, respectively. The films grown from both precursors were stoichiometric and polycrystalline with an increasing contribution from the metastable cubic phase with decreasing film thickness. In the films grown from (CpMe)2ZrMe2, the breakdown field did not essentially depend on the film thickness, whereas in the films grown from (CpMe)2Zr(OMe)Me the structural homogeneity and breakdown field increased with decreasing film thickness. The films exhibited good capacitive properties that were characteristic of insulating oxides and did not essentially depend on the precursor chemistry.

A magnetic atomic laminate from thin film synthesis: (Mo0.5Mn0.5)2GaC

Abstract: We present synthesis and characterization of a new magnetic atomic laminate: (Mo0.5Mn0.5)2GaC. High quality crystalline films were synthesized on MgO(111) substrates at a temperature of ∼530 °C. The films display a magnetic response, evaluated by vibrating sample magnetometry, in a temperature range 3-300 K and in a field up to 5 T. The response ranges from ferromagnetic to paramagnetic with change in temperature, with an acquired 5T-moment and remanent moment at 3 K of 0.66 and 0.35 μB per metal atom (Mo and Mn), respectively. The remanent moment and the coercive field (0.06 T) exceed all values reported to date for the family of magnetic laminates based on so called MAX phases.

Gene set enrichment analysis: A knowledge-based approach for interpreting genome-wide expression profiles

Abstract: Although genomewide RNA expression analysis has become a routine tool in biomedical research, extracting biological insight from such information remains a major challenge. Here, we describe a powerful analytical method called Gene Set Enrichment Analysis (GSEA) for interpreting gene expression data. The method derives its power by focusing on gene sets, that is, groups of genes that share common biological function, chromosomal location, or regulation. We demonstrate how GSEA yields insights into several cancer-related data sets, including leukemia and lung cancer. Notably, where single-gene analysis finds little similarity between two independent studies of patient survival in lung cancer, GSEA reveals many biological pathways in common. The GSEA method is embodied in a freely available software package, together with an initial database of 1,325 biologically defined gene sets.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Fast parallel algorithms for short-range molecular dynamics

Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.