Publications by authors named "Zheng-wei Liu"

Bioaugmentation techniques still show drawbacks in the cleanup of total petroleum hydrocarbons (TPHs) from petroleum-contaminated site soil. Herein, this study explored high-performance immobilized bacterial pellets (IBPs) embed Microbacterium oxydans with a high degrading capacity, and developed a controlled-release oxygen composite (CROC) that allows the efficient, long-term release of oxygen. Tests with four different microcosm incubations were performed to assess the effects of IBPs and CROC on the removal of TPHs from petroleum-contaminated site soil.

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Background: Tuberculosis (TB) outbreaks in schools present a public health challenge. In order to effectively control the spread of transmission, timely screening, accurate diagnosis and comprehensive epidemiological investigations are essential.

Methods: In July 2021, a TB outbreak occurred in a junior high school in Y City, Zhejiang Province.

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The most massive and shortest-lived stars dominate the chemical evolution of the pre-galactic era. On the basis of numerical simulations, it has long been speculated that the mass of such first-generation stars was up to several hundred solar masses. The very massive first-generation stars with a mass range from 140 to 260 solar masses are predicted to enrich the early interstellar medium through pair-instability supernovae (PISNe).

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Background: The aim of this study was to assess the treatment outcomes of multidrug and extensively drug-resistant tuberculosis (M/XDR-TB) in Zhejiang, China and to evaluate possible risk factors associated with poor outcomes of M/XDR-TB.

Methods: Two-hundred-and-sixty-two patients having M/XDR-TB who received the diagnosis and treatment at nine referral hospitals from 1 January 2016 to 31 December 2016 in Zhejiang, China were included. All patients received second-line regimens recommended by WHO under the DOTS-Plus strategy.

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Aim: To determine the etiologies, treatment modalities and visual outcomes of vitreous hemorrhage (VH; range from birth to 18y).

Methods: A total of 262 eyes from 210 patients between January 2010 and September 2016 were included. All children underwent an appropriate ocular and systemic examination.

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Background: Despite significant advancements in the treatment and diagnosis of tuberculosis (TB) over the past decade, drug-resistant TB remains an increasing threat to public health. TB outbreaks are most commonly reported in schools considering the delay in TB diagnosis, sustained contact, and overcrowding observed in schools. This report describes multidrug-resistant TB (MDR-TB) transmission in a school in Zhejiang Province.

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To explore the phenotypic and genotypic characterization of pyrazinamide (PZA) resistance among multidrug-resistant Mycobacterium tuberculosis (MDR-TB) isolates in Zhejiang province, a total of 274 MDR-TB isolates were collected. Drug susceptibility testing and spoligotyping were performed on all clinical isolates. In addition, the mutated features of PZA-resistant loci, including pncA and rpsA, were also analyzed by DNA sequencing.

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Samples of Ho3+/Yb3+ codoped ZrO2-ZnO powder were prepared by a solid-state reaction. Upconversion luminescence of Ho3+ /Yb3+ codoped ZrO2-ZnO powders was reported in the present paper. The excitation spectrum detected at room temperature suggests three excitation peaks centered at 540, 671 and 762 nm respectively, corresponding to 5S2/5F4 --> I8, 5 Fs --> 5 I8, and 5S2/5 F4 --> 5 I7 or 5 I4 --> 5 I8 of Ho3+ ions.

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Samples of Er+3/Yb3+ codoped 3CaO-Al2O3-3SiO2 compounds were prepared, and the properties of frequency upconversion of the samples under the excitation of 980 nm diode laser were studied. Green and red emissions centered at 523, 547 and 656 nm, corresponding to the transitions 2H(11/2)-->4I(15/2), 4S(3/2)-->4I(15/2), and 4F(9/2)-->4I(15/2), respectively, were observed. The dependence of the upconversion fluorescence intensity on the pumping power, and the phonon energy of each sample were observed, and the mechanism of frequency upconversion based on these two items was discussed.

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The rare earth Er3+ doped and Er3+ -Yb3+ co-doped fluoride samples were prepared. Under 980 nm laser excitation, the intense red (650 nm) and green (545 nm) upconversion luminescence was obtained corresponding to the transitions 4S3/2, 2H11/2--4I15/2 and 4F9/2--4I15/2, respectively. For the Er3+ -Yb3+ co-doped fluoride samples, it was found that the ratio of the red upconversion luminescence to the green one decreases as the Er3+ concentration increases.

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Article Synopsis
  • The study focused on various luminescence systems involving Er3+, Tm3+, and Yb3+ at a wavelength of 980 nm, examining their fluorescence spectra.
  • The authors found that the changes in the intensity of green and red light depended on the consistency of Er3+, which was identified as the key factor affecting the luminescence outcomes.
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The direct sensitization up-conversion processes from Yb3+ to Ho3+ and Tm3+ in fluoride were studied. The properties of the up-converted spectra of Yb3+ /Ho3+ and Ho3+ /Yb3+ /Tm3+ co-doped fluorides pumped by a 980 nm laser were compared. Their up-conversion mechanism has been analyzed and discussed.

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Under 980 nm excitation, we obtained five intense up-conversion luminescence bands in Er3+ -Yb3+ -Tm3+ co-doped CdF2: PbF2-based glass as follows: infrared (800 nm), red (645 nm), green (545 nm and 525 nm), blue (480 nm ) and violet (407 nm) up-conversion luminescence. With the addition of Tm3+ , the intensity of 480 nm blue luminescence increased notably compared with that of co-doped Yb3+ -Er3+ sample, which attributed to Tm3+ special energy level structure; logI-logP plot of the luminescence intensity versus pump power shows that 480 nm luminescence emission is a two-photon excitation process induced by the cooperative up-conversion between two Yb3+ ions and the slope of logI-logP plot decreases gradually with increasing pump power and shows a tendency to bend down. The up-conversion mechanism is analyzed in detail under 980 nm semiconductor laser excitation; the dependence of 480 nm up-conversion luminescence intensity on the pump power under the steady states is discussed by using rate equation and the results agree well with the experiments.

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Er3+:Yb3+ co-doped oxy-fluoride glasses with composition of (50-x) GeO2.PbF2.WO3.

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