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  1. Math performance continues to be an important focus for improve- ment. Many districts adopted educational technology programs to support student learning and teacher instruction. The ASSISTments program provides feedback to students as they solve homework problems and automatically prepares reports for teachers about student performance on daily assignments. During the 2018- 19 and 2019-20 school years, we conducted a large-scale randomized controlled trial to replicate the effects of ASSISTments in 63 schools in North Carolina in the US. 32 treatment schools implemented ASSISTments in 7th-grade math class- rooms. Recently, we conducted a follow-up analysis to measure the long-term effects of ASSISTments on student performance one year after the intervention, when the students were in 8th grade. The initial results suggested that implement- ing ASSISTments in 7th grade improved students’ performance in 8th grade and minority students benefited more from the intervention. 
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    Free, publicly-accessible full text available July 1, 2024
  2. Destruction of pharmaceuticals excreted in urine can be an efficient approach to eliminate these environmental pollutants. However, urine contains high concentrations of chloride, ammonium, and bicarbonate, which may hinder treatment processes. This study evaluated the application of ferrate(VI) (FeVIO42-, Fe(VI)) to oxidize pharmaceuticals (carbamazepine (CBZ), naproxen (NAP), trimethoprim (TMP) and sulfonamide antibiotics (SAs)) in synthetic hydrolyzed human urine and uncovered new effects from urine’s major inorganic constituents. Chloride slightly decreased pharmaceuticals’ removal rate by Fe(VI) due to the ionic strength effect. Ammonium (0.5 M) in undiluted hydrolyzed urine posed a strong scavenging effect, but lower concentrations (≤ 0.25 M) of ammonium enhanced the pharmaceuticals’ degradation by 300 µM Fe(VI), likely due to the reactive ammonium complex form of Fe(V)/Fe(IV). For the first time, bicarbonate was found to significantly promote the oxidation of aniline-containing SAs by Fe(VI) and alter the reaction stoichiometry of Fe(VI) and SA from 4:1 to 3:1. In-depth investigation indicated that bicarbonate not only changed the Fe(VI):SA complexation ratio from 1:2 to 1:1, but provided stabilizing effect for Fe(V) intermediate formed in situ, enabling its degradation of SAs. Overall, results of this study suggested that Fe(VI) is a promising oxidant for the removal of pharmaceuticals in hydrolyzed urine. 
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  3. An extruded AZ31B (Mg-3Al-1Zn-0.5Mn) magnesium alloy with a twin volume fraction of 60% was subjected to fully reversed strain-controlled tension-compression along the extrusion direction at strain amplitudes ranging from 0.23% to 0.45%. Dislocation slips were the dominant plastic deformation mechanisms without involving persistent twinning-detwinning. At an identical strain amplitude, the fatigue life of the pre-twinned alloy was much lower than that of the as-extruded alloy. Fatigue cracks were mainly initiated on the prismatic or prismatic-basal slip bands in the parent grains. The material volume reduction of the parent grains in the pre-twinned alloy enhanced fatigue damage. Twin cracks were not observed. 
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  4. This paper presents ferrate(VI) (FeVIO42-, FeVI) oxidation of a wide range of sulfonamide antibiotics (SAs) containing five- and six-membered heterocyclic moieties (R) in their molecular structures. Kinetics measurements of the reactions between FeVI and SAs at different pH (6.5 – 10.0) give species-specific second-order rate constants, k5 and k6 of the reactions of protonated FeVI (HFeO4-) and unprotonated FeVI (FeVIO42-) with protonated SAs (HX), respectively. The values of k5 varied from (1.2 ± 0.1) × 103 to (2.2 ± 0.2) × 104 M-1 s-1, while the range of k6 was from (1.1 ± 0.1) × 102 to (1.0 ± 0.1) × 103 M-1 s-1 for different SAs. The transformation products of reaction between FeVI and sulfadiazine (SDZ, contains a six-membered R) include SO2 extrusion oxidized products (OPs) and aniline hydroxylated products. Comparatively, oxidation of sulfisoxazole (SIZ, a five-membered R) by FeVI has OPs that have no SO2 extrusion in their structures. Density functional theory (DFT) calculations are performed to demonstrate SO2 extrusion in oxidation of SDZ by FeVI. The detailed mechanisms of oxidation are proposed to describe the differences in the oxidation of six- and five-membered heterocyclic moieties (R) containing SAs (i.e., SDZ versus SIZ) by FeVI. 
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  5. The electrically pumped vertical-cavity surface- emitting laser (VCSEL) was first demonstrated with metal cavities by Iga (1979); however, the device threshold current was too high. Distributed Bragg reflector cavities proposed by Scifres and Burnham (1975) were adopted to improve the optical cavity loss. Yet, it was not a practical use until the discovery of the native oxide of AlGaAs and the insertion of quantum wells to provide simultaneous current and optical confinement in semiconductor laser by Holonyak and Dallesasse (1990). Later, the first “low- threshold” oxide-confined VCSEL was realized by Deppe (1994) and opened the door of commercial application for a gigabit energy-efficient optical links. At present, we demonstrated that the oxide-confined VCSELs have advanced error-free data trans- mission [bit-error rate (BER) ≤ 10−12]to 57 Gb/s at 25 °C and 50 Gb/s at 85 °C, and also demonstrated that the pre-leveled 16-quadrature amplitude modulation orthogonal frequency- division multiplexing data were achieved at 104 Gbit/s under back-to-back transmission with the received error vector mag- nitude, SNR, and BER of 17.3%, 15.2 dB, and 3.8 × 10−3, respectively. 
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  6. Free, publicly-accessible full text available August 1, 2024
  7. null (Ed.)
    Genetic screens have been used to identify genes involved in the regulation of different biological processes. We identified growth mutants in a Flp/FRT screen using the Drosophila melanogaster eye to identify conditional regulators of cell growth and cell division. One mutant identified from this screen, B.2.16, was mapped and characterized by researchers in undergraduate genetics labs as part of the Fly-CURE. We find that B.2.16 is a non-lethal genetic modifier of the Dark82 mosaic eye phenotype. 
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