51 research outputs found
Blade-Type Reaction Front in Micrometer-Sized Germanium Particles during Lithiation
To investigate the lithium transport mechanism in micrometer-sized germanium (Ge) particles, in situ focused ion beam–scanning electron microscopy was used to monitor the structural evolution of individual Ge particles during lithiation. Our results show that there are two types of reaction fronts during lithiation, representing the differences of reactions on the surface and in bulk. The cross-sectional SEM images and transmission electron microscopy characterizations show that the interface between amorphous LixGe and Ge has a wedge shape because of the higher Li transport rate on the surface of the particle. The blade-type reaction front is formed at the interface of the amorphous LixGe and crystalline Ge and is attributed to the large strain at the interface
Muon Flux Measurement at China Jinping Underground Laboratory
China Jinping Underground Laboratory (CJPL) is ideal for studying solar-,
geo-, and supernova neutrinos. A precise measurement of the cosmic-ray
background would play an essential role in proceeding with the R\&D research
for these MeV-scale neutrino experiments. Using a 1-ton prototype detector for
the Jinping Neutrino Experiment (JNE), we detected 264 high-energy muon events
from a 645.2-day dataset at the first phase of CJPL (CJPL-I), reconstructed
their directions, and measured the cosmic-ray muon flux to be
cms. The observed angular distributions indicate the leakage of
cosmic-ray muon background and agree with the simulation accounting for Jinping
mountain's terrain. A survey of muon fluxes at different laboratory locations
situated under mountains and below mine shaft indicated that the former is
generally a factor of larger than the latter with the same vertical
overburden. This study provides a convenient back-of-the-envelope estimation
for muon flux of an underground experiment
Performance of the 1-ton Prototype Neutrino Detector at CJPL-I
China Jinping Underground Laboratory (CJPL) provides an ideal site for solar,
geo-, and supernova neutrino studies. With a prototype neutrino detector
running since 2017, containing 1-ton liquid scintillator (LS), we tested its
experimental hardware, performed the physics calibration, and measured its
radioactive backgrounds, as an early stage of the Jinping Neutrino Experiment
(JNE). We investigated the radon background and implemented the nitrogen
sealing technology to control it. This paper presents the details of these
studies and will serve as a key reference for the construction and optimization
of the future large detector at JNE
A practical phosphorus-based anode material for high-energy lithium-ion batteries
State-of-the-art lithium-ion batteries cannot satisfy the increasing energy demand worldwide because of the low specific capacity of the graphite anode. Silicon and phosphorus both show much higher specific capacity; however, their practical use is significantly hindered by their large volume changes during charge/discharge. Although significant efforts have been made to improve their cycle life, the initial coulombic efficiencies of the reported Si-based and P-based anodes are still unsatisfactory (<90%). Here, by using a scalable high-energy ball milling approach, we report a practical hierarchical micro/nanostructured P-based anode material for high-energy lithium-ion batteries, which possesses a high initial coulombic efficiency of 91% and high specific capacity of ~2500 mAh g−1 together with long cycle life and fast charging capability. In situ high-energy X-ray diffraction and in situ single-particle charging/discharging were used to understand its superior lithium storage performance. Moreover, proof-of-concept full-cell lithium-ion batteries using such an anode and a LiNi0.6Co0.2Mn0.2O2 cathode were assembled to show their practical use. The findings presented here can serve as a good guideline for the future design of high-performance anode materials for lithium-ion batteries
Genetic analysis of ORF5 of recent Korean porcine reproductive and respiratory syndrome viruses (PRRSVs) in viremic sera collected from MLV-vaccinating or non-vaccinating farms
The 23 open reading frame (ORF) 5 sequences of Korean type II porcine reproductive and respiratory syndrome virus (PRRSV) were collected from viremic sera from the (modified live vaccine) MLV-vaccinating and non-vaccinating farms from 2007 to 2008. The samples were phylogenetically analyzed with previous ORF5 sequences, including type I Korean PRRSV, and previously reported or collected sequences from 1997 to 2008. A MN184-like subgroup of type II Korean PRRSV was newly identified in the viremic sera collected from 2007 to 2008. And of the type I PRRSVs, one subgroup had 87.2~88.9% similarity with the Lelystad virus, showing a close relationship with the 27~2003 strain of Spain. The maximum parsimony tree of type II PRRSV from 1997 to 2008 showed that they had evolved to four lineages, subgroups 1, 2, 3 and 4. Most of the recently collected type II PRRSVs belonged to subgroup 4 (48%). The region of three B-cell epitopes and two T-cell epitopes of ORF5 amino acids sequences was considerably different from the MLV in subgroups 3 and 4. In conclusion, the existence of type I PRRSV, which was genetically different from Lelystad virus (Prototype of type I PRRSV), and heterologous type II PRRSVs of viremic pigs detected even in the MLV-vaccinating farms indicated the need for new vaccine approaches for the control of PRRSV in Korea
In Situ and Operando Investigation of the Dynamic Morphological and Phase Changes of Selenium-doped Germanium Electrode during (De)Lithiation Processes
To understand the effect of selenium doping on the good cycling performance and rate capability of a Ge0.9Se0.1 electrode, the dynamic morphological and phase changes of the Ge0.9Se0.1 electrode were investigated by synchrotron-based operando transmission X-ray microscopy (TXM) imaging, X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). The TXM results show that the Ge0.9Se0.1 particle retains its original shape after a large volume change induced by (de)lithiation and undergoes a more sudden morphological and optical density change than pure Ge. The difference between Ge0.9Se0.1 and Ge is attributed to a super-ionically conductive Li–Se–Ge network formed inside Ge0.9Se0.1 particles, which contributes to fast Li-ion pathways into the particle and nano-structuring of Ge as well as buffering the volume change of Ge. The XRD and XAS results confirm the formation of a Li–Se–Ge network and reveal that the Li–Se–Ge phase forms during the early stages of lithiation and is an inactive phase. The Li–Se–Ge network also can suppress the formation of the crystalline Li15Ge4 phase. These in situ and operando results reveal the effect of the in situ formed, super-ionically conductive, and inactive network on the cycling performance of Li-ion batteries and shed light on the design of high capacity electrode materials
Extended Kalman Filter with Input Detection and Estimation for Tracking Manoeuvring Satellites
Operando Study of Mechanical Integrity of High-Volume Expansion Li-Ion Battery Anode Materials Coated by Al\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e
Group IV elements and their oxides, such as Si, Ge, Sn and SiO have much higher theoretical capacity than commercial graphite anode. However, these materials undergo large volume change during cycling, resulting in severe structural degradation and capacity fading. Al2O3 coating is considered an approach to improve the mechanical stability of high-capacity anode materials. To understand the effect of Al2O3 coating directly, we monitored the morphology change of coated/uncoated Sn particles during cycling using operando focused ion beam–scanning electron microscopy. The results indicate that the Al2O3 coating provides local protection and reduces crack formation at the early stage of volume expansion. The 3 nm Al2O3 coating layer provides better protection than the 10 and 30 nm coating layer. Nevertheless, the Al2O3 coating is unable to prevent the pulverization at the later stage of cycling because of large volume expansion
Combined glucocorticoids and cyclophosphamide in the treatment of Graves’ ophthalmopathy: a systematic review and meta-analysis
Abstract Purpose To evaluate the efficacy and safety of combined glucocorticoids (GCs) and cyclophosphamide (CYC) treatment in Graves’ ophthalmopathy (GO). Methods We searched PubMed, Embase, Cochrane Library, and four Chinese databases (Chinese National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database (VIP), WanFang, and SinoMed) for any published randomized controlled trials (RCTs) produced from inception to December 1, 2023. Articles obtained using appropriate keywords were selected independently by two reviewers according to the established inclusion and exclusion criteria. Findings We retrieved 1120 records which were eventually reduced to 13 RCTs which were then included in this evaluation. Pooled results indicated that the experimental group (CYC/GCs) showed a higher response rate than control group (GCs or negative control) (RR 1.27; 95% confidence interval 1.19 to 1.37). The subgroup analysis showed that the difference in response rates among treatment protocols (CYC/P, CYC/MPS, CYC/DEX) was not statistically significant (p = 0.23). Implications The combination of GCs and CYC could be recommended as a therapeutic option for GO, especially in patients who experience recurrence after a withdrawal GCs, have a poor response to GCs, or cannot obtain monoclonal antibody agents for various reasons
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