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1.
Proc Natl Acad Sci U S A ; 121(12): e2317809121, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38466842

RESUMO

Magmatism in the Quaternary Clear Lake volcanic field (CLVF), with its youngest eruption having only occurred c. 10 ka ago, is commonly invoked as the heat source for the world's largest commercial geothermal reservoir, The Geysers, in northern California. A shallow silicic magma reservoir in the upper-middle crust has been discovered for some time, but the location and mechanism of a potential deep mafic magma reservoir have remained elusive. Here, we present a seismic tomographic model that images the entire crustal column, clearly revealing a multilevel transcrustal magmatic system beneath the Geysers-Clear Lake area. Upwelling melts from the mantle traverse across the crust-mantle boundary and accumulate in the lower crust underneath the southeastern part of Clear Lake, resulting in a hot Moho in between. Mafic melts primarily ascend westward due to the extensional regime in the west and physical barrier effect from the overlying rigid ophiolite fragment, ultimately forming a shallow silicic magma reservoir underlying and heating The Geysers geothermal field. In addition, this study also links compositionally diverse volcanism in a continental setting to differentiation in a multilevel transcrustal magmatic system.

2.
ACS Omega ; 5(11): 5698-5703, 2020 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-32226847

RESUMO

Studies were made on the influence of temperature and oxygen to carbon ratio (the O/C ratio) on the properties of particles during water coal slurry gasification by taking a new-type coal-water slurry gasifier as the thermal experiment platform, coal-water slurry as a gasification material, and oxygen as the oxidant. The results show that the higher the gasification temperature, the more spherical particles are generated, the higher the content of Na, Fe, and S on the particle surface, and the greater the mass percentage of fine particles. With increase in the O/C ratio, the production of fine particles also increases, while the carbon content of the particles decreases. When the O/C ratio is 1.1, fine particles mainly exist in the form of aggregates; the O/C ratio has little influence on the contents of the particle surface, such as Na, Al, Si, Fe, and S. The effect of the O/C ratio on particle size distribution is most obvious when the ratio is 1: the fine particles are the most prevalent and the coarse particles are the fewest. When the ratio is 1.1, the amount of coarse particles is the largest and the amount of fine particle aggregates is also greater. When the ratio is 0.9, the particle size distribution is intermediate to the two cases.

3.
Anal Chim Acta ; 1046: 115-122, 2019 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-30482288

RESUMO

Lately, an "all-in-one" strategy via direct pyrolysis of protic salt has attracted great attention in the preparation of hetero-doped porous carbons due to its distinctive simplicity. However, protic salt derived carbons usually process large grain sizes thus hamper their applications. Herein, a protic salt derived N, S co-doped porous carbon (N, S-PC) with improved porosity was synthesized by nanocasting and carbonization of protic salt. In the nanocasting silica sphere was used as auxiliary template and an easily obtained protic salt ([pPDA][nHSO4]) was served as C, N and S sources. The obtained N, S-PC contains rich N, S contents and hierarchical textural porosity, thus favors the electrochemical detection of toxic cadmium ions. The N, S-PC based sensor shows excellent sensitivity and selectivity for Cd(II) versus other metals, with a low detection limit of 0.1 µg L-1 (S/N = 3) over a wide concentration range of 4-80 µg L-1. Applications of the N, S-PC based sensor for Cd(II) assay in tap water samples achieved results with good recoveries, indicating that the N, S-PC based electrode is promising in real sample analysis.

4.
Materials (Basel) ; 9(4)2016 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-28773394

RESUMO

Chronic wounds are difficult to heal spontaneously largely due to the corrupted extracellular matrix (ECM) where cell ingrowth is obstructed. Thus, the objective of this study was to develop a three-dimensional (3D) biodegradable scaffold mimicking native ECM to replace the missing or dysfunctional ECM, which may be an essential strategy for wound healing. The 3D fibrous scaffolds of poly(lactic acid-co-glycolic acid) (PLGA) were successfully fabricated by liquid-collecting electrospinning, with 5~20 µm interconnected pores. Surface modification with the native ECM component aims at providing biological recognition for cell growth. Human dermal fibroblasts (HDFs) successfully infiltrated into scaffolds at a depth of ~1400 µm after seven days of culturing, and showed significant progressive proliferation on scaffolds immobilized with collagen type I. In vivo models showed that chronic wounds treated with scaffolds had a faster healing rate. These results indicate that the 3D fibrous scaffolds may be a potential wound dressing for chronic wound repair.

5.
J Nanosci Nanotechnol ; 6(12): 3985-8, 2006 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17256368

RESUMO

Thermally stable organically modified clays based on 1,3-didecyl-2-methylimidazolium (IM2C10) and 1-hexadecyl-2,3-dimethyl-imidazolium (IMC16) were used to prepare poly(ethylene naphthalate) (PEN)/montmorillonite (MMT) nanocomposites via a melt intercalation process. Examination by X-ray diffraction and transmission electron microscopy indicates that an intercalated nanocomposite was formed with IMC16-MMT, while unmodified MMT (Na-MMT) and IM2C10-MMT are generally incompatible with PEN. Thermogravimetric analysis reveals that the peak derivative weight loss temperature of the intercalated PEN/IMC16-MMT was more than 10 "C higher compared to neat PEN, PEN/Na-MMT, or PEN/IM2C10-MMT. Dynamic mechanical analysis also showed that a more significant improvement of the storage modulus was achieved in the better dispersed PEN/IMC16-MMT. The effect of annealing on the dynamic storage modulus of the hybrids is also investigated.


Assuntos
Silicatos de Alumínio/química , Bentonita/química , Cristalização/métodos , Nanoestruturas/química , Nanoestruturas/ultraestrutura , Nanotecnologia/métodos , Polietilenos/química , Argila , Elasticidade , Dureza , Substâncias Macromoleculares/química , Teste de Materiais , Conformação Molecular , Tamanho da Partícula , Propriedades de Superfície , Temperatura , Resistência à Tração
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