bluuebunny/crossref_metadata_2025_split huggingface dataset:
A reinforcement learning approach for hotel revenue management with evidence from field experiments
Authors: Chen Ji , Xu Yifan , Yu Peiwen , Zhang Jun 
Published: March 2023

AbstractWe consider a budget hotel chain's revenue management problem of deciding how to dynamically allocate capacity to multiple segments of customers. Our work solves an industrial‐sized problem faced by practitioners, with the reality of implementation motivating us to develop a tailored reinforcement learning approach. Our approach proceeds in two steps. First, a recommended average discount is computed with a reinforcement learning algorithm. Then, the recommended average discount is turned into a capacity allocation through a linear program. This approach overcomes the challenges of characterizing demand and estimating cancellations, and it facilitates hotel managers' acceptance of the revenue management system. We implement this approach in the hotel chain in a pilot study and assess its effectiveness using synthetic control methods. Our approach improves the key operational performance measure—revenue per available room—by 11.80%. There is heterogeneity in how the pilot hotels improve their revenue per available room. Some mainly increase their occupancy rate, some mainly increase the average daily room rate, while others experience significant increases in both. Further analysis shows that our approach uncovers the individual sources of suboptimal performance in pilot hotels and correspondingly improves decision‐making. Our work demonstrates that a reinforcement learning approach for hotel revenue management is promising.
Plastic spectral interference in the biological characterization by Raman or SERS spectroscopy
Authors: Wang Ping‐Shi , Ma Hao , Xi Xiao‐Han , Yue Xiaxia , Pan Si‐Qi , Cao Maofeng , Liu Guo‐Kun , Wang Xiang , Ren Bin 
Published: March 2023

AbstractRaman spectroscopy and surface‐enhanced Raman spectroscopy (SERS) have been widely applied for characterizing biological samples. Nowadays, it is routine to use plastic products for biological sample preparation and analysis during spectral acquisition. However, plastic containers produce undesirable signals severely interfering with the spectra of biological samples, which is neglectable and misleading. Herein, we unveiled the physical and chemical interference of plastic products in the process of Raman spectroscopy characterization. Firstly, we revisited a representative case of interference from polystyrene plastics on normal Raman and SERS spectra of cysteine and demonstrated its physical interference due to misfocusing. Furthermore, we testified SERS spectra of aqueous solution stored in several plastic materials commonly used in biological experiments. The spectra indicate strong spectral interference from the leaching chemicals. To address these problems, we proposed a series of strategies to avoid interference from plastic products in the Raman and SERS characterization of biological samples.
Separation and determination of triadimefon and its metabolites triadimenol enantiomers in fruit puree by supercritical fluid chromatography
Authors: Zhang Wen‐hua , Xu Dun‐ming , Hou Jian‐bo , He Jian‐min , Zhao Fei , Shi Ying‐zhu , Qian Yan 
Published: March 2023

A method was established for the separation and determination of triadimefon and its metabolite triadimenol enantiomer residues in major complementary fruit puree for infants and young children (banana puree, pineapple puree, and grape puree) by supercritical fluid chromatography. After the samples were extracted with acetonitrile and purified with a solid phase extraction cartridge, Acquity Trefoil CEL2 chiral chromatographic column was adopted for separation, and gradient elution was conducted at the flow rate of 1.0 ml/min under the mobile phase of supercritical carbon dioxide ‐ 0.5% ammonia methanol, the detection wavelength was 220 nm and quantification was conducted with the external standard method. The limits of quantitation of triadimefon and triadimenol enantiomers were both 0.05 mg/kg, the linear ranges were 0.5–50 mg/L, and the linear correlation coefficients were greater than 0.9993. The recoveries in the spiked samples at 0.05, 0.2, and 3.0 mg/kg were from 80.1 to 106%, and the relative standard deviation reached 3.3–7.6%. The method is efficient, rapid, reproducible, and environmentally friendly, enabling accurate analysis of pesticide enantiomers, which can detect the enantiomer residues of triadimefon and its metabolite triadimenol in major complementary fruit puree for infants and young children.
Highly sensitive liquid chromatographic method combined with online ion suppression to remove interfering anions and mass spectrometry for impurity profiling of paromomycin sulfate
Authors: Chen Zhouzhou , Zhu Xiaoyue , Geng Yue , Huang Zhenyu , Adams Erwin , Chen Daijie , Tang Sheng , Yin Yu , Yuan Yaozuo 
Published: March 2023

A previously developed high‐performance liquid chromatography method combined with pulsed amperometric detection allowed to separate many impurities of paromomycin. However, due to the presence of ion pairing agents and sodium hydroxide in the mobile phase, direct coupling to mass spectrometry for the identification of the chemical structures of the impurities was not an option. Indeed, ion suppression was encountered by trifluoroacetic acid and pentafluoroproponic acid in the mobile phase. A cation self‐regenerating suppressor, which was originally designed for increasing analyte conductivity of ammonia and amines analysis in ion chromatography, was coupled between the liquid chromatography and ion trap‐time of flight‐mass spectrometry and almost all trifluoroacetic acid and pentafluoroproponic acid in the mobile phase was removed. The limit of detection of paromomycin in this integrated system improved significantly to 20 ng/ml (0.4 ng). The chemical structures of 19 impurities were elucidated and seven impurities were reported for the first time.
A reconfigurable phase gradient metasurface antenna for beam steering
Authors: Yuan Yi , Ding Jun , Guo Chenjiang , Huang Chao 
Published: March 2023

AbstractIn this article, a reconfigurable phase gradient metasurface (PGM) antenna for beam steering is presented. The antenna consists of a three‐layer transmitarray metasurface and a broadband patch antenna. The PIN diode is loaded onto the split ring resonator (SRR). The phase gradient principle is used to regulate the electromagnetic waves to achieve the function of the gain enhancement and beam tilt. By clever design, the antenna is quickly switched in beam tilt in the 8.9–9.9 GHz range and gain enhancement in the 7.9–9.4 GHz range without the need for additional circuits. The proposed PGM antenna can achieve beam tilt in a certain bandwidth range and gain enhancement simultaneously. Compared with the previous beam steering antenna, it has broader bandwidth and smaller volume. The experimental results are in good agreement with the simulated ones.
Experimental investigation on mechanical behaviors of composite sandwich panels with a hybrid facesheet
Authors: Zhu Shuhua , Wang Yuequan , Zhou Long , Yi Wentao , Hu Li , Liu Jian , Kang Xinran , Li Hongshuang 
Published: March 2023

AbstractA multi‐functional composite sandwich panel was developed with a hybrid facesheet, which was composed of a quartz fiber reinforced plastic (QFRP) laminate and two copper layers. The other facesheet was made of QFRP laminate. The Nomex® honeycomb was used as the core material. The aim of this paper is to investigate the effects of the hybrid facesheet on the mechanical characterizations of the sandwich panel. Four mechanical performances of both composite sandwich panel with and without copper layers were considered, including the flatwise tensile strength test, the edgewise compressive strength test, the three‐point bending test and the tensile plate shear test. The experimental results show that all the four mechanical performances of the sandwich panel with copper layers were lower than the sandwich panel without copper layers. The flatwise tensile strength decreased by 26.1%. The edgewise compressive strength decreased by 9.5%. The shear strength obtained from the three‐point bending test decreased by 14.9%. The shear strength obtained from tensile plate shear test decreased by 13.7%.
Modification of Nafion's nanostructure for the water management of PEM fuel cells
Authors: Li Yuanchao , Linnell Schwab Natalie , Briber Robert M. , Dura Joseph A. , Nguyen Trung Van 
Published: March 2023

AbstractA PEM fuel cell with the Nafion ionomer phase of the cathode catalyst layer (CL) that was exposed to hot dry gas during the hot‐pressing process showed improved performance over the whole current density range and ~ 220% peak power increase with humidified air at 80°C. This enhanced performance is attributed to the modified structure of the perfluorosulfonic acid (PFSA) ionomer layer in the CL during the MEA's hot‐pressing process. The dry gas exposure above the glass transition temperature (Tg) results in the aggregation of the ionic groups to retain the residue water molecules. This process separates the ionomer into ionic‐group‐rich domains and ionic‐group‐sparse domains. The ionic‐group‐sparse domains create hydrophobic interface and reactant transport channels with lower water content and thus higher oxygen solubility in the ionomer. Accordingly, the water‐unsaturated ionomer and its surface hydrophobicity enhance the kinetic‐controlled and concentration‐polarized regions of the fuel cell polarization curve, respectively. The surface hydrophobicity of the ionomer layer is analyzed by the contact angle measurement and XPS. The durability of the hydrophobic effect below Tg is demonstrated by boiling the treated material. Re‐treating the hydrophobic sample with humidified gas exposure above Tg eventually exhibits hydrophilic features, further proving the manipulability of the ionic group distribution.
The effect of citrate plasticizers on the properties of nitrocellulose granules
Authors: Gańczyk‐Specjalska Katarzyna , Cieślak Katarzyna , Jakubczak Marcin , Drożdżewska‐Szymańska Katarzyna , Tomaszewski Waldemar , Prasuła Piotr 
Published: March 2023

AbstractNitrocellulose granules containing the proposed new eco‐friendly inert plasticizers, substitutes for phthalate derivatives, such as acetyl triethyl nitrate (ATEC) and tributyl citrate (TBC) were obtained. The single‐base propellants were obtained using safe granulation process (water method). Diethylene glycol dinitrate (DEGDN) was used as an energetic modifier in obtained propellants. It was found that the addition of citrate plasticizers reduced the heat of combustion and dynamic vivacity of powders. At the same time DEGDN increased the heat of combustion of tested materials. Citrate derivatives did not affect the density and thermal decomposition of granules. It was concluded based on pyrostatic analysis that the TBC plasticizer influenced the kinetics of nitrocellulose gelatinization by DEGDN. The kinetic model [nth order with autocatalysis (CnB) reaction] was adjusted based on the process of thermal decomposition. The presence of DEGDN in granules reduces the activation energy and increases the constant heat cumulative rate. The prepared propellants are characterized by excellent thermal stability in accordance with the STANAG 4582 standard. The obtained propellants can be potentially used in small calibre ammunition.
Influence of combination of coaxial cylindrical explosives on fragmentation and shock waves of a shelled composite charge
Authors: Li Jun‐bao , Li Wei‐bing , Wang Xiao‐ming , Zou Bin 
Published: March 2023

AbstractThis paper investigates fragmentation and shock waves generated by a novel coaxial cylindrical composite charge composed of an inner explosive, an intermediate inert material and an outer explosive widely used in tunable ammunition. Charges containing two types of explosive combinations were designed, and explosion experiments were conducted in two initiation modes: detonating only an inner explosive and detonating inner and outer explosives simultaneously. Results suggest the composite charge with higher inner‐detonation velocity and lower outer‐detonation velocity achieves more differentiated power output under different initiations. The differences in the average fragment mass and peak overpressure are as high as 34.5 % and 39.9 %, respectively, which are larger than 4.4 % and 8.4 % under the contrary explosive combination. On the basis of this observation, corresponding 2‐D and 3‐D models were simulated using AUTODYN code to investigate the evolution of the detonation waveform and detonation energy release. The numerically simulated initial shell expansion and later shock wave propagation of the composite charge agreed well with the experimental data. The errors in expansion radius and shock wave parameters (peak overpressure and specific impulse) are less than 6.6 % and 16.9 %, respectively, between the simulations and experiments. It was found that the particle velocity profile in the charge with lower outer‐detonation velocity lagged behind that of the charge with higher inner‐detonation velocity under inner initiation, while a wave front collision zone close to the outer charge appeared in the non‐detonation layer under simultaneous initiation.
Science education with multilingual learners: Equity as access and equity as transformation
Authors: Grapin Scott E. , Pierson Ashlyn , González‐Howard María , Ryu Minjung , Fine Caitlin , Vogel Sara 
Published: March 2023

AbstractResearch in science education with multilingual learners (MLs) has expanded rapidly. This rapid expansion can be situated within a larger dialogue about what it means to provide minoritized students with an equitable education. Whereas some conceptions of equity focus on ensuring all students have access to the knowledge, practices, and language normatively valued in K‐12 schools (equity as access), increasingly prominent conceptions focus on transforming those knowledge, practices, and language in ways that center minoritized students and their communities (equity as transformation). In this article, we argue that conceptions of equity provide a useful lens for understanding emerging research in science education with MLs and for charting a research agenda. We begin by tracing how conceptions of equity have evolved in parallel across STEM and multilingual education. Then, we provide an overview of recent developments from demographic, theoretical, and policy perspectives. In the context of these developments, we provide a conceptual synthesis of emerging research by our team of early‐career scholars in three areas: (a) learning, (b) assessment, and (c) teacher education. Within each area, we unpack the research efforts in terms of how they attend to equity as access while pushing toward equity as transformation. Finally, we propose a research agenda for science education with MLs that builds on and extends these efforts. We close by offering recommendations for making this research agenda coherent and impactful: (a) being explicit about our conceptions of equity, (b) paying attention to the interplay of structure and agency, and (c) promoting interdisciplinary collaboration.
Single‐Atom Gd Nanoprobes for Self‐Confirmative MRI with Robust Stability
Authors: Luo Qing , Liu Junhan , Ma Qian , Xu Suying , Wang Leyu 
Published: March 2023

AbstractGadolinium (Gd)‐based complexes are extensively utilized as contrast agents (CAs) in magnetic resonance imaging (MRI), yet, suffer from potential safety concerns and poor tumor targeting. Herein, as a mimic of Gd complex, single‐atom Gd nanoprobes with r1 and r2 values of 34.2 and 80.1 mM−1 s−1 (far higher than that of commercial Gd CAs) at 3 T are constructed, which possessed T1/T2 dual‐mode MRI with excellent stability and good tumor targeting ability. Specifically, single‐atom Gd is anchored on nitrogen‐doped carbon matrix (Gd‐NxC) through spatial‐confinement method, which is further subjected to controllable chemical etching to afford fully etched bowl‐shape Gd‐NxC (feGd‐NxC) with hydrophilic properties and defined coordination structure, similar to commercial Gd complex. Such nanostructures not only maximized the Gd3+ site exposure, but also are suitable for self‐confirmative diagnosis through one probe with dual‐mode MRI. Moreover, the strong electron localization and interaction between Gd and N atoms afforded feGd‐NxC excellent kinetic inertness and thermal stability (no significant Gd3+ leaching is observed even incubated with Cu2+ and Zn2+ for two months), providing a creative design protocol for MRI CAs.
Bio‐Inspired Electro‐Thermal‐Hygro Responsive Rewritable Systems with Temporal/Spatial Control for Environment‐Interactive Information Display
Authors: Wu Shuangshuang , Shi Huihui , Wei Shuxin , Shang Hui , Xie Weiping , Chen Xipao , Lu Wei , Chen Tao 
Published: March 2023

AbstractUtilization of rewritable luminescent materials for secure information storage and delivery has long been envisaged to reduce the cost and environmental wastes. However, it remains challenging to realize a temporally/spatially controlled display of the written information, which is crucial for secure information encryption. Here, inspired by bioelectricity‐triggered skin pattern switching in cephalopods, an ideal rewritable system consisting of conductive graphene film and carbon dots (CDs) gel with blue‐to‐red fluorescence‐color changes via water‐triggered CDs aggregation and re‐dispersion is presented. Its rewritability is guaranteed by using water ink to write on the CDs‐gel and employing Joule heat of graphene film to evaporate water. Due to the highly controlled electrical stimulus, temporally/spatially controlled display is achieved, enabling on‐demand delivery and duration time regulation of the written information. Furthermore, new‐concept environment‐interactive rewritable system is obtained by integrating sensitive acoustic/optical sensors and multichannel electronic time‐delay devices. This work opens unprecedented avenues of rewritable systems and expands potential uses for information encryption/delivery.
Enhanced Sonodynamic Cancer Therapy through Iron‐Doping and Oxygen‐Vacancy Engineering of Piezoelectric Bismuth Tungstate Nanosheets
Authors: Ding Yiming , Zhao Yunchao , Yao Shuncheng , Wang Shaobo , Wan Xingyi , Hu Quanhong , Li Linlin 
Published: March 2023

AbstractSonodynamic therapy (SDT) is regarded as a new‐rising strategy for cancer treatment with low invasiveness and high tissue penetration, but the scarcity of high‐efficiency sonosensitizers has seriously hindered its application. Herein, the iron‐doped and oxygen‐deficient bismuth tungstate nanosheets (BWO‐Fe NSs) with piezotronic effect are synthesized for enhanced SDT. Due to the existence of oxygen defects introduced through Fe doping, the bandgap of BWO‐Fe is significantly narrowed so that BWO‐Fe can be more easily activated by exogenous ultrasound (US). The oxygen defects acting as the electron traps inhibit the recombination of US‐induced electrons and holes. More importantly, the dynamically renewed piezoelectric potential facilitates the migration of electrons and holes to opposite side and causes energy band bending, which further promotes the production of reactive oxygen species. Furthermore, Fe doping endows BWO‐Fe with Fenton reactivity, which converts hydrogen peroxide (H2O2) in tumor microenvironment into hydroxyl radicals (•OH), thereby amplifying the cellular oxidative damage and enhancing SDT. Both in vitro and in vivo experiments illustrate their high cytotoxicity and tumor suppression rate against refractory breast cancer in mice. This work may provide an alternative strategy to develop oxygen‐deficient piezoelectric sonosensitizers for enhanced SDT via doping metal ions.
Regulating the Coordination Geometry and Oxidation State of Single‐Atom Fe Sites for Enhanced Oxygen Reduction Electrocatalysis
Authors: Wang Minjie , Wang Li , Li Qingbin , Wang Dan , Yang Liu , Han Yongjun , Ren Yuan , Tian Gang , Zheng Xiaoyang , Ji Muwei , Zhu Caizhen , Peng Lishan , Waterhouse Geoffrey I. N. 
Published: March 2023

AbstractFeNC catalysts demonstrate remarkable activity and stability for the oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells and Zn–air batteries (ZABs). The local coordination of Fe single atoms in FeNC catalysts strongly impacts ORR activity. Herein, FeNC catalysts containing Fe single atoms sites with FeN3, FeN4, and FeN5 coordinations are synthesized by carbonization of Fe‐rich polypyrrole precursors. The FeN5 sites possess a higher Fe oxidation state (+2.62) than the FeN3 (+2.23) and FeN4 (+2.47) sites, and higher ORR activity. Density functional theory calculations verify that the FeN5 coordination optimizes the adsorption and desorption of ORR intermediates, dramatically lowering the energy barrier for OH− desorption in the rate‐limiting ORR step. A primary ZAB constructed using the FeNC catalyst with FeN5 sites demonstrates state‐of‐the‐art performance (an open circuit potential of 1.629 V, power density of 159 mW cm−2). Results confirm an intimate structure‐activity relationship between Fe coordination, Fe oxidation state, and ORR activity in FeNC catalysts.
Stable LiF‐Rich Electrode–Electrolyte Interface toward High‐Voltage and High‐Energy‐Density Lithium Metal Solid Batteries
Authors: Yang Tianqi , Zhang Wenkui , Lou Jiatao , Lu Huanming , Xia Yang , Huang Hui , Gan Yongping , He Xinping , Wang Yao , Tao Xinyong , Xia Xinhui , Zhang Jun 
Published: March 2023

AbstractLithium‐rich layered oxide (LRLO) materials have attracted significant attention due to their high specific capacity, low cost, and environmental friendliness. However, owing to its unique capacity activation mechanism, the release of lattice oxygen during the first charge process leads to a series of problems, such as severe voltage decay, poor cycle stability, and poor rate performance. Herein, a fluorinated quasi‐solid‐state electrolyte (QSSE) via a simple thermal polymerization method toward lithium metal batteries with LRLO materials is reported. The well‐designed QSSE exhibits an ionic conductivity of 6.4 × 10−4 S cm−1 at 30 °C and a wide electrochemical stable window up to 5.6 V. Most importantly, XPS spectra demonstrate the generation of a LiF‐rich electrode–electrolyte interface (EEI), where the in situ generated LiF provides strong protection against the structural degradation of LRLO materials and directs the uniform plating/stripping behaviors of lithium‐ions to inhibit the formation of lithium dendrites. As a result, LRLO/QSSE/Li batteries exhibit excellent rate performance and demonstrate a large initial capacity for 209.7 mA h g−1 with a capacity retention of 80.8% after 200 cycles at 0.5C. This work provides a new insight for the LiF‐rich EEI design of safe, high‐performance quasi‐solid‐state lithium metal batteries.