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"Huang, Qing"
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Critical role of water in the formation of continental crust
Continental arcs are the sites of production of continental crust, but the origin of these magmatic systems is not well understood. Although a number of processes have been suggested to be important, the role of water migrating from slab to surface during subduction has been underappreciated. Directly below the Moho, hot (approximately 1,100 °C), hydrous basaltic magmas fractionate as they cool to the regional geotherm at 750 to 800 °C, ultimately solidifying as mafic underplates. Cooling and fractionation cause water to exsolve and ascend, triggering fluid-fluxed melting of overlying mafic underplates and other crust. Melting of prior mafic underplates buffers temperatures and generates the voluminous, juvenile low-K magmas of Cordilleran batholiths. These granitoid magmas comprise a low-temperature slurry of melt and residue, and recrystallize into silicic mush during adiabatic ascent. Such hydrous mushes are intermittently infused by hotter, more mafic magmas, which hybridize and facilitate ascent and, potentially, eruption. Fluid-fluxed melting overcomes many of the general petrological and geochemical problems associated with models dominated by fractional crystallization. The role of water during repeated episodes of mafic underplating is critical to generate the juvenile granitoid infrastructure of the continents.Migration of water from the slab to the surface during subduction is highlighted as a key process in the formation of continental crust.
Journal Article
Oxygen Defect Engineering Promotes Synergy Between Adsorbate Evolution and Single Lattice Oxygen Mechanisms of OER in Transition Metal‐Based (oxy)Hydroxide
The oxygen evolution reaction (OER) activity of transition metal (TM)‐based (oxy)hydroxide is dominated by the number and nature of surface active sites, which are generally considered to be TM atoms occupying less than half of surface sites, with most being inactive oxygen atoms. Herein, based on an in situ competing growth strategy of bimetallic ions and OH − ions, a facile one‐step method is proposed to modulate oxygen defects in NiFe‐layered double hydroxide (NiFe‐LDH)/FeOOH heterostructure, which may trigger the single lattice oxygen mechanism (sLOM). Interestingly, by only varying the addition of H 2 O 2 , one can simultaneously regulate the concentration of oxygen defects, the valence of metal sites, and the ratio of components. The proper oxygen defects promote synergy between the adsorbate evolution mechanism (AEM, metal redox chemistry) and sLOM (oxygen redox chemistry) of OER in NiFe‐based (oxy)hydroxide, practically maximizing the use of surface TM and oxygen atoms as active sites. Consequently, the optimal NiFe‐LDH/FeOOH heterostructure outperforms the reported non‐noble OER catalysts in electrocatalytic activity, with an overpotential of 177 mV to deliver a current density of 20 mA cm −2 and high stability. The novel strategy exemplifies a facile and versatile approach to designing highly active TM‐LDH‐based OER electrocatalysts for energy and environmental applications.
Journal Article
Single-atom Rh/N-doped carbon electrocatalyst for formic acid oxidation
To meet the requirements of potential applications, it is of great importance to explore new catalysts for formic acid oxidation that have both ultra-high mass activity and CO resistance. Here, we successfully synthesize atomically dispersed Rh on N-doped carbon (SA-Rh/CN) and discover that SA-Rh/CN exhibits promising electrocatalytic properties for formic acid oxidation. The mass activity shows 28- and 67-fold enhancements compared with state-of-the-art Pd/C and Pt/C, respectively, despite the low activity of Rh/C. Interestingly, SA-Rh/CN exhibits greatly enhanced tolerance to CO poisoning, and Rh atoms in SA-Rh/CN resist sintering after long-term testing, resulting in excellent catalytic stability. Density functional theory calculations suggest that the formate route is more favourable on SA-Rh/CN. According to calculations, the high barrier to produce CO, together with the relatively unfavourable binding with CO, contribute to its CO tolerance.Atomically dispersed Rh on N-doped carbon exhibits 28- and 67-fold enhancements compared with state-of-the-art Pd/C and Pt/C, despite the low activity of Rh/C. The Rh single atoms exhibit high tolerance to CO poisoning compared to Rh nanoparticles.
Journal Article
Facilely tuning the intrinsic catalytic sites of the spinel oxide for peroxymonosulfate activation
Heterogeneous peroxymonosulfate (PMS)–based advanced oxidation processes (AOPs) have shown a great potential for pollutant degradation, but their feasibility for largescale water treatment application has not been demonstrated. Herein, we develop a facile coprecipitation method for the scalable production (∼10 kg) of the Cu-Fe-Mn spinel oxide (CuFeMnO). Such a catalyst has rich oxygen vacancies and symmetry-breaking sites, which endorse it with a superior PMS-catalytic capacity. We find that the working reactive species and their contributions are highly dependent on the properties of target organic pollutants. For the organics with electron-donating group (e.g., -OH), high-valent metal species are mainly responsible for the pollutant degradation, whereas for the organics with electron-withdrawing group (e.g., -COOH and -NO₂), hydroxyl radical (•OH) as the secondary oxidant also plays an important role.We demonstrate that the CuFeMnO–PMS system is able to achieve efficient and stable removal of the pollutants in the secondary effluent from a municipal wastewater plant at both bench and pilot scales. Moreover, we explore the application prospect of this PMS-based AOP process for large-scale wastewater treatment. This work describes an opportunity to scalably prepare robust spinel oxide catalysts for water purification and is beneficial to the practical applications of the heterogeneous PMS-AOPs.
Journal Article
How the dark energy can reconcile Planck with local determination of the Hubble constant
We try to reconcile the tension between the local 2.4 % determination of Hubble constant and its global determination by
Planck
CMB data and BAO data through modeling the dark energy variously. We find that the chi-square is significantly reduced by
Δ
χ
all
2
=
-
6.76
in the redshift-binned dark energy model where the
68
%
limits of the equation of state of dark energy read
w
(
0
≤
z
≤
0.1
)
=
-
1
.
958
-
0.508
+
0.509
,
w
(
0.1
<
z
≤
1.5
)
=
-
1
.
006
-
0.082
+
0.092
, and here
w
(
z
>
1.5
)
is fixed to
-
1
.
Journal Article
Gallium nitride catalyzed the direct hydrogenation of carbon dioxide to dimethyl ether as primary product
The selective hydrogenation of CO
2
to value-added chemicals is attractive but still challenged by the high-performance catalyst. In this work, we report that gallium nitride (GaN) catalyzes the direct hydrogenation of CO
2
to dimethyl ether (DME) with a CO-free selectivity of about 80%. The activity of GaN for the hydrogenation of CO
2
is much higher than that for the hydrogenation of CO although the product distribution is very similar. The steady-state and transient experimental results, spectroscopic studies, and density functional theory calculations rigorously reveal that DME is produced as the primary product via the methyl and formate intermediates, which are formed over different planes of GaN with similar activation energies. This essentially differs from the traditional DME synthesis via the methanol intermediate over a hybrid catalyst. The present work offers a different catalyst capable of the direct hydrogenation of CO
2
to DME and thus enriches the chemistry for CO
2
transformations.
The conversion of CO
2
to valuable chemicals is still challenged by catalyst developments. Herein, the authors found that GaN is an efficient catalyst for selective CO
2
hydrogenation to dimethyl ether as the primary product, in contrast to the traditional methanol-intermediate route over hybrid catalysts.
Journal Article
Integrated single-cell transcriptome analysis reveals heterogeneity of esophageal squamous cell carcinoma microenvironment
The tumor microenvironment is a highly complex ecosystem of diverse cell types, which shape cancer biology and impact the responsiveness to therapy. Here, we analyze the microenvironment of esophageal squamous cell carcinoma (ESCC) using single-cell transcriptome sequencing in 62,161 cells from blood, adjacent nonmalignant and matched tumor samples from 11 ESCC patients. We uncover heterogeneity in most cell types of the ESCC stroma, particularly in the fibroblast and immune cell compartments. We identify a tumor-specific subset of CST1
+
myofibroblasts with prognostic values and potential biological significance. CST1
+
myofibroblasts are also highly tumor-specific in other cancer types. Additionally, a subset of antigen-presenting fibroblasts is revealed and validated. Analyses of myeloid and T lymphoid lineages highlight the immunosuppressive nature of the ESCC microenvironment, and identify cancer-specific expression of immune checkpoint inhibitors. This work establishes a rich resource of stromal cell types of the ESCC microenvironment for further understanding of ESCC biology.
The microenvironment of oesophageal squamous cell carcinomas (ESCC) is heterogeneous and can strongly impact response to treatment. Here, the authors characterize the ESCC tumour microenvironment with single-cell RNA-seq, finding CST1 + myofibroblasts with potential biological and prognostic significance as well as immunosuppression signatures.
Journal Article
Non-tensorial gravitational wave background in NANOGrav 12.5-year data set
We perform the first search for an isotropic non-tensorial gravitational-wave background (GWB) allowed in general metric theories of gravity in the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) 12.5-year data set. By modeling the GWB as a power-law spectrum, we find strong Bayesian indication for a spatially correlated process with scalar transverse (ST) correlations whose Bayes factor versus the spatially uncorrelated common-spectrum process is 107 ± 7, but no statistically significant evidence for the tensor transverse, vector longitudinal, and scalar longitudinal polarization modes. The median and the 90% equal-tail amplitudes of ST mode are
A
ST
=
1.06
−
0.28
+
0.35
×
10
−
15
, or equivalently the energy density parameter per logarithm frequency is
Ω
GW
ST
=
1.54
−
0.71
+
1.21
×
10
−
9
, at frequency of 1/year.
Journal Article
Constraints on the neutrino mass and mass hierarchy from cosmological observations
Considering the mass splitting between three active neutrinos, we represent the new constraints on the sum of neutrino mass
∑
m
ν
by updating the anisotropic analysis of the Baryon Acoustic Oscillation (BAO) scale in the CMASS and LOWZ galaxy samples from Data Release 12 of the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS DR12). Combining the BAO data of 6dFGS, MGS, LOWZ and CMASS with
Planck
2015 data of temperature anisotropy and polarizations of the Cosmic Microwave Background (CMB), we find that the 95 % C.L. upper bounds on
∑
m
ν
refer to
∑
m
ν
,
N
H
<
0.18
eV for the normal hierarchy (NH),
∑
m
ν
,
I
H
<
0.20
eV for the inverted hierarchy (IH) and
∑
m
ν
,
D
H
<
0.15
eV for the degenerate hierarchy (DH), respectively, and the normal hierarchy is slightly preferred over the inverted one (
Δ
χ
2
≡
χ
NH
2
-
χ
IH
2
≃
-
3.4
). In addition, the additional relativistic degrees of freedom and massive sterile neutrinos are neither favored at present.
Journal Article