Application of a hybrid multiscalar indicator in drought identification in Beijing and Guangzhou,China

The Palmer drought severity index(PDSI) is physically based with multivariate concepts, but requires complicated calibration and cannot easily be used for multiscale comparison. Standardized drought indices(SDIs), such as the standardized precipitation index(SPI) and standardized precipitation evapotranspiration index(SPEI), are multiscalar and convenient for spatiotemporal comparison, but they are still challenged by their lack of physical basis. In this study, a hybrid multiscalar indicator, the standardized Palmer drought index(SPDI), was used to examine drought properties of two meteorological stations(the Beijing and Guangzhou stations) in China, which have completely different drought climatologies. The results of our case study show that the SPDI is correlated with the well-established drought indices(SPI, SPEI, and PDSI) and presents generally consistent drought/wetness conditions against multiple indicators and literature records. Relative to the PDSI, the SPDI demonstrates invariable statistical characteristics and better comparable drought/wetness frequencies over time and space. Moreover,characteristics of major drought events(drought class, and onset and end times) indicated by the SPDI are generally comparable to those detected by the PDSI. As a physically-based standardized multiscalar drought indicator, the SPDI can be regarded as an effective development of the Palmer drought indices, providing additional choices and tools for practical drought monitoring and assessment.

Ionic-Liquid-Gating Induced Protonation and Superconductivity in FeSe,FeSe0.93S0.07, ZrNCl, 1T-TaS2 and Bi2Se3

We report protonation in several compounds by an ionic-liquid-gating method, under optimized gating conditions.This leads to single superconducting phases for several compounds. Non-volatility of protons allows post-gating magnetization and transport measurements. The superconducting transition temperature Tc is enhanced to 43.5 K for FeSe0.93S0.07, and 41 K for Fe Se after protonation. Superconducting transitions with Tc^15 K for ZrNCl,~7.2 K for 1-TaS2, and ~3.8 K for Bi2Se3 are induced after protonation. Electric transport in protonated FeSe0.93S0.07 confirms high-temperature superconductivity. Our ^1H nuclear magnetic resonance(NMR)measurements on protonated Fe Se1-xSx reveal enhanced spin-lattice relaxation rate 1/^1T1 with increasing x,which is consistent with the LDA calculations that H+ is located in the interstitial sites close to the anions.

Goodness-of-fit tests for multi-dimensional copulas:Expanding application to historical drought data

The question of how to choose a copula model that best fits a given dataset is a predominant limitation of the copula approach, and the present study aims to investigate the techniques of goodness-of-fit tests for multi-dimensional copulas. A goodness-of-fit test based on Rosenblatt＇s transformation was mathematically expanded from two dimensions to three dimensions and procedures of a bootstrap version of the test were provided. Through stochastic copula simulation, an empirical application of historical drought data at the Lintong Gauge Station shows that the goodness-of-fit tests perform well, revealing that both trivariate Gaussian and Student t copulas are acceptable for modeling the dependence structures of the observed drought duration, severity, and peak. The goodness-of-fit tests for multi-dimensional copulas can provide further support and help a lot in the potential applications of a wider range of copulas to describe the associations of correlated hydrological variables. However, for the application of copulas with the number of dimensions larger than three, more complicated computational efforts as well as exploration and parameterization of corresponding copulas are required.

Superconducting properties of the C15-type Laves phase ZrIr_(2) with an Ir-based kagome lattice

We report systematic studies on superconducting properties of the Laves phase superconductor ZrIr_(2).It crystallizes in a C15-type(cubic MgCu_(2)-type,space group Fd3m)structure in which the Ir atoms form a kagome lattice,with cell parameters a=b=c=7.3596(1)?.Resistivity and magnetic susceptibility measurements indicate that ZrIr_(2) is a type-Ⅱsuperconductor with a transition temperature of 4.0 K.The estimated lower and upper critical fields are 12.8 mT and 4.78 T,respectively.Heat capacity measurements confirm the bulk superconductivity in ZrIr_(2).ZrIr_(2) is found to possibly host strong-coupled s-wave superconductivity with the normalized specific heat change△C_(e)/γT_(c)~1.86 and the coupling strength△_(0)/k_BT_(c)~1.92.First-principles calculations suggest that ZrIr_(2) has three-dimensional Fermi surfaces with simple topologies,and the states at Fermi level mainly originate from the Ir-5d and Zr-4d orbitals.Similar to SrIr_(2) and ThIr_(2),spin–orbit coupling has dramatic influences on the band structure in ZrIr_(2).

Substitution effect on the superconductivity in Mo_(3-x)Re_xAl_(2)C withβ-Mn structure prepared by microwave method

We report the microwave synthesis and the doping effect of Mo_(3-)xRe_xAl_(2)C(0≤x≤0.3)superconductor.Re doping into Mo_(3)Al_(2)C results in a regular shrinkage of the lattice,marked by the linear decrease of lattice parameter a from6.868(1)A(for Mo_(3)Al_(2)C)to 6.846(2)A(for Mo_(2.7)Re_(0.3)Al_(2)C).Upon Re doping,T_(c)of Mo_(3-x)Re_xAl_(2)C first increases and then decreases,with the maximum T_(c)=9.14 K at the optimal doping level of x=0.09.Our report provides a convenient method to synthesize Mo_(3-)xRe_xAl_(2)C within minutes,and also marks the first Re doping study with enhanced superconductivity on the non-centrosymmetric superconductor Mo_(3)Al_(2)C.

Structural and electrical transport properties of Cu-doped Fe1-xCuxSe single crystals

We report the structural and electrical transport properties of Fe1-xCuxSe(x=0,0.02,0.05,0.10)single crystals grown by a chemical vapor transport method.Substituting Cu for Fe suppresses both the nematicity and superconductivity of FeSe single crystal,and provokes a metal–insulator transition.Our Hall measurements show that the Cu substitution also changes an electron dominance at low temperature of un-doped Fe Se to a hole dominance of Cu-doped Fe1-xCuxSe at x=0.02 and 0.1,and reduces the sign-change temperature(TR)of the Hall coefficient(RH).

Superconductivity with a Violation of Pauli Limit and Evidences for Multigap in η-Carbide Type Ti_(4)Ir_(2)O

We report the synthesis,crystal structure,and superconductivity of Ti_(4)Ir_(2)O.The title compound crystallizes in an η-carbide type structure of the space group Fd3m(No.227),with lattice parameters a=b=c=11.6194(1)A.The superconducting temperature T_(c) is found to be 5.1-5.7 K.Most surprisingly,Ti_(4)Ir_(2)O hosts an upper critical field of 16.45 T,which is far beyond the Pauli paramagnetic limit.Strong coupled superconductivity with evidences for multigap is revealed by the measurements of heat capacity and upper critical field.First-principles calculations suggest that the density of states near the Fermi level originates from the hybridization of Ti-3d and Ir-5d orbitals,and the effect of spin-orbit coupling on the Fermi surfaces is prominent.Large values of the Wilson ratio(R_(W)∼3.9),the Kadowaki-Woods ratio[A/γ^(2)∼9.0×10^(−6)µΩ·cm/(mJ·mol^(−1)·K^(−1))^(2)],and the Sommerfeld coefficient(γ=33.74 mJ·mol^(−1)·K^(−2))all suggest strong electron correlations(similar to heavy fermion systems)in Ti_(4)Ir_(2)O.The violation of Pauli limit is possibly due to a combination of strong-coupled superconductivity and large spin-orbit scattering.With these intriguing behaviors,Ti_(4)Ir_(2)O serves as a candidate for unconventional superconductor.

Survival differences between definitive radiotherapy and surgery followed by adjuvant radiotherapy in supraglottic and hypopharyngeal carcinoma

Background:Organ preservation has long been a consideration in the treatment of supraglottic and hypopharyngeal carcin improve the quality of life(QOL).Definitive radiotherapy(DRT)with or without systematic treatment,such as chemotherapy,is always the first choice to achieve improved QOL.This retrospective study focused on the survival differences between DRT and surgery followed by adjuvant radiotherapy(S+RT)in supraglottic and hypopharyngeal carcinoma.Methods:This study included adult patients with supraglottic or hypopharyngeal carcinoma undergoing single-modality treatment with either DRT or S+RT between January 2012 and August 2016.A total of 59 patients were identified,of whom 31 were treated with DRT,and 28 were treated with S+RT.In the 31 cases of DRT,23 cases were treated with concurrent chemoradiotherapy(CRT),one case was treated with DRT plus cetuximab,and seven cases were treated with DRT alone.Of the other 28 cases of S+RT,15 cases were treated with adjuvant concurrent CRT.Survival analysis was used to compare the overall survival(OS),local recurrence-free survival(LRFS)and distant metastasis-free survival(DMFS)between DRT and S+RT groups.Results:The median follow-up was 20 months(range,4-67 months).The patients of the two groups were similar with respect to mean age,original sites,and tumor stages.The 1-,2-,and 5-year OS rates were 80.6%,53.4%,and 24.7% for the DRT group and 85.7%,67.1%,and 24.7%for the S+RT group,respectively.There was no significant difference between the two groups(x^2=3.183,P=0.074).The 1-,2-,and 5-year LRFS and DMFS were 90.4%,61.7%,and 18.0%and 87.4%,49.2%,and 9.9%,respectively,and no statistical difference was observed between the two groups(LRFS:x^2=0.028,P=0.868;DMFS:x^2=3.347,P=0.067).No significant difference was found between the two groups in acute radiotoxicity.Conclusions:Without loss of laryngeal function,the survival of DRT is comparable to that of S+RT in supraglottic and hypopharyngeal carcinoma.

Strong-coupling superconductivity with T_(c)~10.8 K induced by P doping in the topological semimetal Mo_(5)Si_(3)

By performing P doping on the Si sites in the topological semimetal Mo_(5)Si_(3),we discover strong-coupling superconductivity in Mo_(5)Si_(3-x)P_(x)(0.5≤x≤2.0).Mo_(5)Si_(3)crystallizes in the W_(5)Si_(3)-type structure with space group of I4/mcm(No.140),and is not a superconductor itself.Upon P doping,the lattice parameter a decreases while c increases monotonously.Bulk superconductivity is revealed in Mo_(5)Si_(3-x)P_(x)(0.5≤x≤2.0)from resistivity,magnetization,and heat capacity measurements.T_(c)in Mo_(5)Si_(1.5)P_(1.5)reaches as high as 10.8 K,setting a new record among the W_(5)Si_(3)-type superconductors.The upper and lower critical fields for Mo_(5)Si_(1.5)P_(1.5)are 14.56 T and 105 mT,respectively.Moreover,Mo_(5)Si_(1.5)P_(1.5)is found to be a fully gapped superconductor with strong electron-phonon coupling.First-principles calculations suggest that the enhancement of electron-phonon coupling is possibly due to the shift of the Fermi level,which is induced by electron doping.The calculations also reveal the nontrivial band topology in Mo_(5)Si_(3).The T_(c)and upper critical field in Mo_(5)Si_(3-x)P_(x) are fairly high among pseudobinary compounds.Both of them are higher than those in NbTi,making future applications promising.Our results suggest that the W_(5)Si_(3)-type compounds are ideal platforms to search for new superconductors.By examinations of their band topologies,more candidates for topological superconductors can be expected in this structural family.