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Stabilization Strategies Of Pt Catalysts Forproton Exchange Membrane Fuel Cells, Da-Ping He, Shi-Chun Mu

Journal of Electrochemistry

The low service lifetime of proton exchange membrane fuel cells (PEMFCs) is the main bottleneck for their commercial applications. One of the main factors is that the expensive metal Pt catalyst is easy to degradation under the harsh working environment of PEMFC (such as variable voltage, strong acidity, gas-liquid two-phase flow), which leads to the inevitable decay of the catalytic performance, thus, seriously restricting the lifetime of PEMFC. Therefore, the electrochemical stability of Pt-based electrocatalysts has become an important and hot topic to improve the PEMFC lifetime. In this paper, we review the recent development in enhancing the stability of …

The Pilot Application Of Electrochemical Impedance Spectroscopy On Dynamic Proton Exchange Membrane Fuel Cell, Jian-Wei Guo, Jian-Long Wang

Journal of Electrochemistry

By analyzing Electrochemical Impedance Spectroscopy (EIS) in applications of dynamic proton exchange membrane fuel cell (PEMFC), bottlenecks which restrict EIS tool development have been pointed out in this paper. Though the high-frequency resistance in EIS is largely accepted as cell inner-resistance, this can only be applied for cell with low current. The low-frequency resistance is difficult to be realized due to its relation with mass transfer. Furthermore, the improved Randles equivalent circuits are built up preliminarily, thus, penetrating into studies for mass transfer reaction, cell operation/degeneration, and high temperature fuel cell. Inspiringly, EIS is becoming an analyzing tool for stack …

Evidence For Terahertz Acoustic Phonon Parametric Oscillator Based On Acousto-Optic Degenerate Four-Wave Mixing In A Silicon Doping Superlattice, Thomas E. Wilson

Physics Faculty Research

We report evidence for a 1.0-THz self-starting mirrorless acoustic phonon parametric oscillator (MAPPO) produced from acousto-optic phase-conjugate degenerate four-wave (D4WM) mixing in a THz laser-pumped silicon doping superlattice (DSL). The DSL was grown by molecular beam epitaxy on a (100) boron-doped silicon substrate. A superconducting NbTiN subwavelength grating was used to couple the THz laser radiation into the DSL. Superconducting granular aluminum bolometric detection, coupled with Si:B piezophonon spectroscopy, revealed excitation of THz coherent compressional and shear waves, along the ⟨111⟩ direction only. The Bragg scattering condition for distributed feedback, and the energy conservation requirement for the D4WM process, were …

Assessment Of Inequalities In Coverage Of Essential Reproductive, Maternal, Newborn, Child, And Adolescent Health Interventions In Kenya, Emily Catherine Keats, Nadia Akseer, Zaid Bhatt, William Macharia, Anthony Ngugi, Arjumand Rizvi, Zulfiqar Ahmed Bhutta

Paediatrics and Child Health, East Africa

Importance: Previous work has underscored subnational inequalities that could impede additional health gains in Kenya.

Objective: To provide a comprehensive assessment of the burden, distribution, and change in inequalities in reproductive, maternal, newborn, child, and adolescent health (RMNCAH) interventions in Kenya from 2003 to 2014.

Design, Setting, and Participants: This population-based cross-sectional study used data from the 2003, 2008, and 2014 Kenya Demographic and Health Surveys. The study included women of reproductive age (ages 15-49 years) and children younger than years, with national, regional, county, and subcounty level representation. Data analysis was conducted from April 2018 to November 2018.

Exposures: …

Study Of The Reactions E+E-→Π+Π-Π0Π0Π0 And Π+Π-Π0Π0Η At Center-Of-Mass Energies From Threshold To 4.35 Gev Using Initial-State Radiation, J. P. Lees, V. Poireau, V. Tisserand, E. Grauges, A. Palano, G. Eigen, D. N. Brown, Yu G. Kolomensky, M. Fritsch, H. Koch, T. Schroeder, C. Hearty, T. S. Mattison, J. A. Mckenna, R. Y. So, V. E. Blinov, A. R. Buzykaev, V. P. Druzhinin, V. B. Golubev, E. A. Kozyrev, Milind Purohit, Jeffrey Wilson, Et. Al.

Faculty Publications

We study the processes e⁺e⁻ → π⁺π⁻π⁰π⁰π⁰nγ in which an energetic photon is radiated from the initial state. The data are collected with the BABAR detector at SLAC. About 14 000 and 4700 events, respectively, are selected from a data sample corresponding to an integrated luminosity of 469 fb⁻¹. The invariant mass of the hadronic final state defines the effective e⁺e⁻ center-of-mass energy. From the mass spectra, the first precise measurement of the e⁺e⁻ → π⁺π^{− …}

Research Progress In Hydrogen Evolution Low Noble/Non-Precious Metal Catalysts Of Water Electrolysis, Yang Li, Zhao-Yan Luo, Jun-Jie Ge, Chang-Peng Liu, Wei Xing

Journal of Electrochemistry

Hydrogen energy technology with hydrogen as an energy carrier is gaining more and more attention due to its cleanliness and high energy density. Hydrogen fuel cell vehicles have been listed as one of the ultimate energy technologies in the 21st century. Among them, sustainable hydrogen production technology is a necessary prerequisite for the future development of hydrogen energy economy. Electrolyzed water technology driven by renewable resources represents an important way to support the sustainable development of hydrogen energy economy. The development and utilization of high activity, low cost hydrogen evolution catalysts is a key factor in improving the efficiency and …

Growth Characteristics Of Newly Isolated Indonesian Microalgae Under Different Salinity, Wa Iba, Michael A. Rice, Lucie Maranda, Gary H. Wikfors

Fisheries, Animal and Veterinary Sciences Faculty Publications

The aim of this study was to investigate the growth characteristics of microalgae strains isolated from Kendari Bay and the Wanggu River estuary, Indonesia. The growth of the isolates, denoted as Kb1-2, Kb1-3, Kb1-5, and Kb2-6, were evaluated under controlled conditions. A batch culture experiment of these strains except Kb2-6 was conducted for 15 days under salinity levels of 20, 25, 30 and 35 gL-1. Tetraselmis chui, Tisochrysis lutea and Chaetocero sneogracile were also culture and used as the growth references. Cell density was measured every day and cell size was measured from 50 live cells during the logarithmic …

Checkpoint Inhibitors: What Gastroenterologists Need To Know., Monjur Ahmed

Division of Gastroenterology and Hepatology Faculty Papers

Checkpoint inhibitors are increasingly being used in clinical practice. They can cause various gastrointestinal, hepatic and pancreatic side effects. As these side effects can be serious, appropriate management is essential. The different checkpoint inhibitors with their mechanisms of action and indications, as well as evaluation and management of gastrointestinal, hepatic and pancreatic side effects, are discussed in this article.

Fuel Cell Performance Curve After Mea Optimization Structural Optimization Of Low Pt Membrane Electrode Assembly, Yan Rao, Shang Li, Fen Zhou, Tian Tian, Qing Zhong, Zhao-Hui Wan, Jin-Ting Tan, Mu Pan

Journal of Electrochemistry

Membrane electrode assemblies (MEAs) are the key component of proton exchange membrane fuel cell. For a long time, much attention has been paid to develop MEA technology. At present, the research, development and industrialization of fuel cell has entered a new era. More strict requirements for MEA, especially for the reduction of Pt loading with a challenging target of 0.125 mg·W^-1 have to be met. In this paper, the performance losses under low Pt loading are analyzed in terms of activation polarization, ohm polarization and mass-transfer polarization. It is proposed that research should be focused on the activity of …

Morphological Control Of Ptcu2 Octahedron And Oxygen Reduction Electrocatalytic Performance Of Ptcu For Fuel Cell, Long-Sheng Cao, Lei Wan, Zhi-Gang Shao, Hong-Mei Yu, Ming Hou, Bao-Lian Yi

Journal of Electrochemistry

Platinum acetylacetonate (Pt(acac)₂) and copper acetylacetonate (Cu(acac)₂) were co-reduced to prepare PtCu₂ octahedron alloy catalyst in N,N-dimethylformamiade by solvothermal method. The PtCu₂ showed lattice compression, and high ratio of non-oxidized Pt with high electronic binding energy. All those structural features contributed to weak adsorption strength of oxygen species on Pt and lower d-band centre position. The influence of structure-directing agent on morphology of PtCu alloy was systematically studied. In the half cell test, as a result of the uniform morphology and regular octahedron of PtCu₂ formed, the mass activity and area specific activity …

Effects Of So2 In Air On Performance Of Direct Methanol Fuel Cell, Bin Qin, Fen-Ning Jing, Xue-Jing Sun, Gong-Quan Sun, Hai Sun

Journal of Electrochemistry

Direct methanol fuel cells (DMFC) generally use oxygen as an oxidant. Contaminants such as sulfides and nitrides in the air can affect the performance of the DMFC. In this work, the effects of SO₂ on the performance of DMFC were investigated and the mechanism of poisoning was analyzed, by means of constant current discharge curve, polarization performance curve, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). In the CV scan, the permeated methanol was oxidized at a low potential to eliminate its effect on the SO₂ poisoning behavior test. The results showed that the SO₂ poisoning resulted …

The Relative Financial Cost And Benefit Of An Ophthalmology Resident Compared To An Advanced Practice Provider, Optometrist, Or Faculty Ophthalmologist, Daniel Moore, William Barr

Journal of Academic Ophthalmology

Objective The main objective of the article is to determine the relative direct financial cost and benefit of an advanced practice provider (APP), optometrist, and faculty ophthalmologist compared with an ophthalmology resident.

Design Single center cost–benefit financial analysis.

Methods The direct total expenses, including mean salary and benefits; the cost/week, based upon calculated hours worked; and net revenue, based upon technical collections subtracted from total expenses were collected for all APPs, optometrists, faculty ophthalmologists, and ophthalmology residents at the University of Kentucky for the 2016 to 2017 academic year. Optometry and ophthalmology faculty collections were adjusted for clinical full-time equivalents. …

Recent Progress In Pt-Based Catalysts For Oxygen Reduction Reaction, Jing Li, Xin Feng, Zi-Dong Wei

Journal of Electrochemistry

One major challenge for a large-scale commercialization of the proton-exchange membrane fuel cells (PEMFCs) technologies that enable a shift to ‘zero-emission’ personal transportation, is the expensive and unstable Pt catalysts, which are mainly used to catalyze the sluggish kinetics of the oxygen reduction reaction (ORR) occurred on the air electrode of PEMFCs. Many research works have targets to improve the stability of Pt-based catalysts and to construct Pt/transitional metal alloys with low Pt loading amount. Herein, we provide a minireview for the Pt-based ORR catalysts based on our recent work, which covers a brief background introduction, the stability improvement of …

Search For The Rare Decay Of B+→ℓ+Νℓγ With Improved Hadronic Tagging, Belle Collaboration, R. Kroeger

Faculty and Student Publications (Open Access)

No abstract provided.

Study Of The Reactions E+E−→Π+Π−Π0Π0Π0 And Π+Π−Π0Π0Η At Center-Of-Mass Energies From Threshold To 4.35 Gev Using Initial-State Radiation, Babar Collaboration, R. Cheaib, L. Cremaldi, R. Godang, D. J. Summers

Faculty and Student Publications (Open Access)

No abstract provided.

Search For Pair-Produced Resonances Decaying To Quark Pairs In Proton-Proton Collisions At S=13 Tev, Cms Collaboration, J. G. Acosta, S. Oliveros

Faculty and Student Publications (Open Access)

No abstract provided.

Recurrent Pneumonia In Children At A Tertiary–Pediatric Hospital In Baghdad, Muhi Kadhem Al-Janabi, Nadia Aziz Nasir, Rafed Kareem Jaber, Abbas Oweid Oleiwe

Iraqi Postgraduate Medical Journal

ABSTRACT: BACKGROUND: There are many children suffering from Recurrent Pneumonia (RP). Children with RP may present a difficult diagnostic challenge. OBJECTIVE: This study was performed to evaluate the frequency levels and underlying causes of RP in Children Welfare Teaching Hospital (CWTH)/Medical City/Baghdad. PATIENTS AND METHODS: In this prospective hospital-based cross-sectional study, 107 children admitted with RP in CWTH in the period from March to July 2014. Children were included in this study if they had at least 2 times pneumonia per year or three ever in life proved by radiographic confirmation during hospital admission. Children were classified according to underlying …

Fuel Cells Reactor For Chemicals And Electric Energy Cogeneration, Zhi-Lin Heng, Xiao-Zi Yuan, Yi-Mei Yin, Zi-Feng Ma

Journal of Electrochemistry

As an energy conversion device, fuel cells can efficiently convert chemical energy into electrical energy. With the developing of technology, it is used as a reactor to conduct the synthesis of high value-added chemicals while generating electrical energy. Having benefits such as mild reaction conditions, controllability of the reaction process, high selectivity of the product, as well as high efficiency of energy utilization, it is widely used in many fields such as preparation of high value-added industrial products, gas separation, water treatment, etc. This paper introduces the current trends and statuses of fuel cell reactors in the cogeneration of chemicals …

Creative Solution Focused Counseling Models (Csfcm): Strategi Kreatif Untuk Mengembangkan Self-Regulated Learning Siswa, Wahyu Nanda Eka Saputra, Augusto Da Costa, Said Alhadi

Jurnal Kajian Bimbingan dan Konseling

The study aimed to develop CSFCM to improve student self-regulated learning. CSFCM is an application of solution-focused counseling integrated with creative arts. The developmental research consisted of three stages: (1) identify the self-regulated learning level; (2) formulating a hypothetical draft of CSFCM to improve student self-regulated learning; and (3) conducting product feasibility testing by experts and practitioners. Data analysis technique used quantitative descriptive analysis. The results showed that the CSFCM which consisting five stages of counseling was categorized as feasible to be implement in the schools.

Inhibition Of Heat-Induced Aggregation Of Tilapia Myosin By Dextran Sulfate At Low Ionic Strength, Li Ting, Zhou Chunxia, Feng Rui, Hong Pengzhi

Food and Machinery

Studied, the inhibitory effect of DS on thermal aggregation of tilapia myosin (2.0 mg/mL) in low ionic strength (1, 50, 150 mmol/L KCl) during the heat treatment (40～80 ℃, 1 ℃/min). The result showed that the myosin had poor solubility in 1 mmol/L KCl. While, with the icreased of ionic strengths, myosin fibrils could dissociate in 50 and 150 mmol/L KCl. After heating, the myosin filaments disappeared, and the heads and tails of myosin aggregated seriously, resulting in the solubility and the content of α-helix decreased significantly. After adding 0.4 mg/mL DS, the change of turbidity, solubility and α-helix content …

Effects Of Microwave On Free Radical Production And Oxidative Properties Of Model Protein, Wang Tingting, Yuan Jiangfeng, Wang Lunji, Zhang Bin, Qiu Zhijun, Gong Minggui, Yin Qihang

Food and Machinery

Bovine Serum Albumin (BSA), a model protein, was used to study the relationship between the free radical production and oxidative properties in the microwave field. Electron paramagnetic resonance (EPR) trapping with 5,5-dimethyl-l-pyrrolin N-oxide (DMPO) was used for the detection of free radical produced by BSA under different microwave treatment conditions. The signal intensity of free radicals arose from BSA solution via the increasing of power, temperature, and time after microwave irradiation. By measuring the carbonyl, thiol and surface hydrophobic oxidative properties of BSA under different microwave temperatures. It was showed that the carbonyl content increased, the thiol content decreased, and …

Effects Of Aging Time And Cooking Degree On Volatile Flavors Of Beef, Wang Hengpeng, Wu Peng, Chen Shengsu, Tu Mingliang, Gao Ziwu, Xie Jing, Yang Tianyi, Chen Chang, Meng Xiangren

Food and Machinery

In order to study the effects of aging time, cooking degree and their interaction on beef flavor components, the longissimus dorsi of Simmental cattle in the process of aging time (3, 5, 7 d) were selected to make steaks of medium, medium well and well done. Volatile flavor components in different aging times and cooking degree were analyzed by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), explored the best aging time and cooking degree which were beneficial to flavor substances formated. Results showed that, a total of 50 volatile compounds were identified in each beef sample. The …

Determination And Content Analysis Of Phenolic Compounds In Different Late-Maturing Citrus Of China, Zhang Jing, Zhu Lisha, Zhang Yaohai, Zhao Jing, Dong Chao, Jiao Bining

Food and Machinery

In order to provide scientific basis for the utilization of citrus resource and improvement of comprehensive utilization value of fruits, the ultra-performance liquid chromatography (UPLC) was used to determine the main phenolic substances (flavonoied and phenolic acids) in nine Chinese late-maturing citrus. The different phenolic compounds and their contents were analyzed in pulp, juice and peel. The results showed that flavonoids were mainly hesperidin in the parts of the nine citrus varieties, and phenolic acids were mainly ferulic acid, and the content of PMFs in the pericarp was rich. In the juice of nine citrus, the contents of hesperidin and …

Determination Of Benzaldehyde Residues Contents In Honey By Hplc-Ms Using Rhodamine B Hydrazide As The Pre-Column Derivatization Reagent, Peng Xue, Han Rui, Chen Liying, Wang Yue, Zhu Guiping, Cao Ruifang, Zhong Tingting, Shen Guanghui, Luo Qingying, Zhang Zhiqing, Li Shanshan

Food and Machinery

A novel HPLC-MS method was established, using a synthesized rhodamine B hydrazide (RBH) as the new pre-colunm derivatization reagent. After extracted with methanol and derivatized with RBH, the samples were determined by high-performance liquid chromatography(HPLC) coupled with mass spectrometry(MS). The results showed that the reagent RBH has a good sensitivity for mass spectrometry detection, and the derivatization reaction of benzaldehyde was efficient and specific. The benzaldehyde showed a good linear relationship in the range of 0.05～6.00 ng/mL, and the correlation coefficient was 0.996 2. The detection limits and quantitation limits of the method were 0.80×10^-3 ng/mL and 2.71×10^{-3 …}

Rapid Quantitative Prediction Model Of Adulterated Goat Milk Based On Electronic Tongue, Han Hui, Wang Zhiqiang, Li Caihong, Ma Zeliang, Guo Tingting, Yin Tingjia

Food and Machinery

In order to discriminate adulterated goat milk quickly and objectively, a set of portable electronic tongue detection system was exploited, and a new method of fast identification is developed. When detected in the system, the sample solution was first scanned to obtain the "fingerprint" information of adulterated goat milk, and then the discrete wavelet transform (DWT) was used to obtain the characteristics of the "fingerprint" data. On this basis, the principal component analysis (PCA) was used to determine the quality of goat milk with different adulteration ratio. Particle swarm optimization extreme learning machine (PSO-ELM) was applied to quantitatively predict goat …

Migration And Change Of Heavy Metal During The Pickling Of Candied Fruits, Li Wenxiang, Zhou Songhang, Wang Can, Long Qiang, Liu Yang, Lin Wenhua, Cao Xiaoyan

Food and Machinery

In this study, based on the determination of heavy metal residues in raw materials, the migration behavior of heavy metal in candied fruits was preliminary analyzed by monitoring dynamic changes of heavy metal content during pickling. The results showed that the contents of Plumbum, Cadmium, Chromium, Mercury and Arsenic in raw materials were 0.151 0, 0.024 1, 0.110 0, 0.000 0, 0.013 2 mg/kg, respectively; During the pickling process, residual heavy metal elements could migrate into the pickling solution, and significant differences were found in migration and relative behavior for different heavy metal elements. The contents of Plumbum, Cadmium, Cadmium …

Study On The Packaging Quality Stability Of Paper-Packaging Machines For Chinese Dried Noodles, Zong Xiangdong, Fu Junhui, Jiao Zuiping, Wang Ruibin, Zhao Bo, Wei Yimin

Food and Machinery

To determine the packaging quality stability of paper-packaging machines (HNQ) for Chinese dried noodles based on the key technology improvement, and to meet demands from noodle industries to packaging stability and efficiency, the production lines of a dried noodles manufacturing industry were sampled for investigation. The packaging effects of two kinds of packaging machines (HNQ and SDH) and four same machines in a line were for each kind were tested and analyzed. The results showed that no significant difference in the instant weight of packaged noodles between the SDH packaging machines was found. The differences of coefficient variation (CV%) among …

Design Of Intelligent Milk Machine Based On User Behavior Contact, Wang Weiwei, Wang Wei, Li Huanni

Food and Machinery

In order to optimize and upgrade the intelligent milk machine, solve the problems encountered during the operation, a intelligent milk machine that improves the user's operating experience was designed by analyzing the users' behavioral contacts. The users’ behavior were observed to identify the touch points of using process and sort the contact priorities. Moreover, intelligent milk machine was designed by analytic hierarchy process. According to the design method, the demand point was transformed into a design opportunity to construct a intelligent milk machine design framework. Based on user behavior, intelligent milk machine was produced for the users to operate it …

The Changes Intexture And Physicochemical Properties Of Giant Freshwater Prown (Macrobrachium Rosenbergii) During Frozen Storage, Liu Jiatong, Jiang Qixing, Yang Fang, Wang Bin, Xu Yanshun, Xia Wenshui, Xu Yan

Food and Machinery

The texture and physicochemical properties of giant freshwater prawn during frozen storage were investigated in this study. The quality differences of frozen whole prawn and headless prawn were compared and analyzed by shear stress, myofibrillar fragmentation index, myofibrillar apparent diameter, TCA soluble peptide and total protease activity. The results showed that the shear force of prawn decreased with the extension of storage time. The shear force of frozen whole prawn decreased more rapidly than headless prawn. After 16 weeks, the shear force of frozen whole prawns and headless shrimp decreased by 36.81% and 25.40%. The myofibril fragmentation index and TCA …

Effect Of Electrostatic Field Combind With Controlled Freezing-Point Storage Technology On The Quality Of Litopenaeus Vannamei In Storage Period, Duan Weiwen, Quan Qinguo, Zhang Xueqin, Zhang Zewei, Chen Ming, Zeng Xuege, Liu Shucheng, Ji Hongwu

Food and Machinery

Used the electrostatic field combined with controlled freezing-point storage technology to preserve the Litopenaeus vannamei, and examined the effects of different electrostatic field（1.5,2.5,3.5 kV）combined with controlled freezing-point storage（-1 ℃±1 ℃）on quality of Litopenaeus vannamei. Some quality index changes were compared in Polyphenol Oxidase （PPO） relative enzyme activity, whiteness, sensory, total bacterial counts, TVB-N, pH, drip loss, K value and rheology property. The results showed that electrostatic field inhibited the PPO relative enzyme activity, the sensory and whiteness significantly better than the controlled freezing-point storage. In the late period of storage, the total bacterial counts was inhibited by electrostatic field and …