bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the domain of attraction and local stabilization of nonlinear parameter‐varying systems
Authors: Lu Linhong , Fu Rong , Zeng Jianping , Duan Zhisheng 
Published: October 2019

SummaryIn this paper, the domain of attraction (DA) and the local stabilization problem are investigated under the nonlinear parameter‐varying (NPV) framework. Specifically, to take into account the time‐varying parameter, we generalize the definition of robust DA (RDA) and propose the concept of parameter‐dependent DA (PDA) for NPV systems, together with the sum‐of‐squares (SOS) conditions for their estimations. Differently from the existing DA‐related works, the theoretical results in this paper can be applied to a large class of nonlinear polynomial systems including the time‐invariant, the parameter‐dependent, and the uncertain ones. Moreover, the commonly used iterative/coordinate‐wise search is avoided because we eliminate the bilinear product terms between the Lyapunov functional and the SOS multipliers. We also consider the local stabilization problem of NPV systems, in which the RDA can be specified as a control performance index. Finally, several examples are given for illustration purposes.
Tunable Thermo‐ and pH‐Responsive Hydrogels and MWCNTs/Hydrogel Containing 2‐Aminobenzamide Units in Their Crosslink Chains
Authors: Karimi Ali R. , Nikravesh Golara , Bayat Fahimeh , Khodadadi Azam , Tarighatjoo Mahsa 
Published: October 2019

AbstractIn the present article, a new class of chitosan hydrogels containing 2‐aminobenzamide units in their crosslink chains was prepared by reaction of chitosan with different percentages of bis‐isatoic anhydride as cross‐linker at 70 °C. Then, multi‐walled carbon nanotubes (MWCNTs)/hydrogel nanocomposites were fabricated by crosslinking of chitosan with bis‐isatoic anhydride in the presence of 0.1% and 0.3% (w/w) MWCNTs. Scanning electron microscopy images have verified a 3D porous nanostructure with uniform morphology which MWCNTs were dispersed uniformly on the matrix of hydrogel nanocomposite. The swelling behaviours of the hydrogels and their nanocomposites were investigated by swelling the gels in media of different temperatures and pH. The results indicated the pH‐thermo dual behaviour of hydrogels. Finally, metronidazole was selected as a model drug for the investigation of the drug release properties of the prepared hydrogels. The metronidazole release was affected by physical properties of medium and chemical content of hydrogels.
Hollow α‐Fe2O3 Nanotubes Embedded in Graphene Aerogel as High‐Performance Anode Material for Lithium‐Ion Batteries
Authors: Wang Lingfeng , Wei Guo , Dong Xiaoyu , Zhao Yulong , Xing Zheng , Hong Haiping , Ju Zhicheng 
Published: October 2019

AbstractHematite, with the higher theoretical capacity, as one of the most promising alternatives attract great attention in lithium‐ion batteries (LIBs). However, it is suffers from severe volume expansion and shrinkage during the insertion and extraction of Li ions. Here novel 3D graphene aerogel load with hollow Fe2O3 nanotubes was synthesized with the help of polyvinyl pyrrolidone (PVP) and N‐Methyl pyrrolidone (NMP) by a simple hydrothermal method. Serving as an anode material for LIBs, this composite manifested great cycle performance of high columbic efficiency (97%∼99%), high specific discharged capacity (1512 mAh g−1 at 100 mA g−1) and high rate capability (280 mAh g−1 at 5 A g−1). The superior performance of the material mainly depends on the interaction of graphene sheets and hollow Fe2O3 nanotubes. The 3D framework affords shorter diffusion distance for Li ions and enormous area to accommodate the volume expansion during the insertion/extraction of Li ions. Herein, this composite demonstrates a new way to modify the morphology of Fe2O3 and displays high efficiency and good performance as the anode of LIBs.
Density Functional Computations for Co(I)‐Catalyzed Intermolecular Hydroacylation of Benzaldehydes
Authors: Wang Fen , Meng Qingxi 
Published: October 2019

AbstractDensity functional theory (DFT) was employed to study and expound Co(I)‐catalyzed intermolecular hydroacylation of benzaldehydes. The ωB97XD/6‐31G(d,p) level (LANL2DZ(f) for I and Co) was applied to optimize all intermediates and transition states. The computational results revealed that Co(I)‐catalyzed hydroacylation went primarily through the oxidative addition, hydrogen migration, and reductive elimination, the rate‐limiting step was the reductive elimination, and the ester was dominating product. The complexation of benzaldehyde occurred prior to its oxidative addition in the active three‐coordinated cobalt‐diphosphine‐benzaldehyde intermediate. The decarbonylation would be prohibited as a result of high relative Gibbs free energies. Moreover, the role of iodide ion, the additive iPr2NEt, and the solvent toluene were studied in detail.
Electrochemical Exfoliation of Graphite to Fluorographene: An Effect of Degree of Functionalization on 2Br−/Br2 Redox Reaction
Authors: Yeddala Munaiah , Narayanan Tharangattu N. , Pitchai Ragupathy , Pillai Vijayamohanan K. 
Published: October 2019

AbstractIn this work, we employed the electrochemical exfoliation (EE) to synthesize and tune the degree of functionalization in fluorinated graphene (FG) and studied its (degree of functionalization) effect on bromine redox reaction. The degree of functionalization was tuned by varying the concentration of the electrolyte. Physical characterization of as‐synthesized FG reveals that fluorine and oxygen content varies from 2.32 to 3.92 atomic % and from 10.46 to 21.16 atomic % respectively. The concentration of fluoride to hydroxide ion ratio should be at an optimum level in the electrolyte to get maximum degree of fluorination, which shows a sizeable effect on bromine redox reaction. The bromine redox reaction is more reversible on highly FG and less reversible on less FG and Oxygen functionalities has no effect on the reaction. The kinetic parameters such as rate constant (k) (varying from 1.45 x 10−3 to 52.43 x 10−3 mA/cm2) and exchange current density (io) (varying from 2.61 x 10−4 to 9.92 x 10−4 cm/s) suggest that nature and degree of functionalization play a vital role to improve the kinetics of redox reaction of bromine. This investigation can pave paths to design new and sustainable electrode materials for bromine‐based redox flow batteries.
Effect of Cobalt Phthalocyanine on Synthesis and Physicochemical Properties of Polyaniline
Authors: Andriianova Anastasiia N. , Mustafin Akhat G. , Abdrakhmanov Ildus B. 
Published: October 2019

AbstractOrganic transition metal complexes are successfully used in polymerization due to their catalytic activity in oxidative reactions. Here, polyaniline was synthesized with cobalt phthalocyanine as catalysts for the aniline oxidative polymerization. The conditions for obtaining polyaniline significantly affect the final product and the introduction of the component into the reaction mixture leads to a change in the physicochemical properties of the polymer. Thus, the effect of the catalyst on the polymer chain was determined using FTIR, UV‐visible spectral methods and atomic adsorption analysis. Electrical conductivity, thermal stability, electrochemical parameters (HOMO‐LUMO, band gap), surface morphology, and fluorescence emission spectra were estimated for the polymer samples obtained. The study of synthesized polymeric materials resulted that the use of cobalt phthalocyanines in the aniline oxidative polymerization process leads to better physicochemical properties, namely electrical conductivity, band gap and fluorescence quantum yield.
The Hydrolysis Equilibrium Effect of Water with Cu(II) Catalysts Used for the Selective Synthesis of Xylitol Monoacetals as Bio‐Based Surfactants
Authors: Tang Qiong , Li Xu , Dong Jinxiang 
Published: October 2019

AbstractXylitol obtained from the biomass was converted into selective products via acetalization with long‐chain aldehydes in the presence of water. The results demonstrate that CuSO4 may be a promising catalyst for the synthesis of monoacetals from n‐octanal. Upon adding the corresponding sodium salt to inhibit the hydrolysis reaction, CuSO4 was less efficient at promoting the reaction when compared to other soluble copper salts (CuCl2, Cu(NO3)2 and Cu(OTf)2) because of its low Lewis acid activity in water. According to the results obtained under different pH conditions, the CuSO4 catalyst was able to selectively prepare the monoacetal because the initial reaction rate was controlled using gradual hydrolysis. Two other monoacetals obtained from n‐hexanal and n‐decanal were also synthesized. In addition, the surfactant properties of all the as‐prepared monoacetals were evaluated.
Construction of 2D/2D Heterogeneous of ZIF‐8/SnS2 Composite as a Transfer of Band‐Band System for Efficient Visible Photocatalytic Activity
Authors: Chou Xiaoyu , Ye Jin , Cui Mimi , Li Yudong , He Yanzhen , Liu Xiaofei , Wang Hongchao 
Published: October 2019

AbstractConstructing two‐dimensional (2D) heterostructured nanocomposites is an effective method to boost photo‐generated carrier separation efficiently using layer material. In this work, a tightly coupled 2D/2D ZIF‐8/SnS2 nanosheet heterogeneous composite was successfully prepared. Due to the good heterogeneous interface between 2D SnS2 and 2D ZIF‐8 nanosheet, 2D/2D ZIF‐8/SnS2 nanocomposites formed a large contact interface, leading to high efficient interfacial charge transfer efficiency and shortening the distance of charge transmission. As a result, the optimized SnS2/2D‐ZIF‐8 composites possess excellent photocatalytic properties and the rate of degradation toward MB under visible light for 100 minutes is 2.32 and 26.75 times than that of pure SnS2 and 2D‐ZIF‐8, respectively. This work offers an efficient way to design 2D/2D heterojunction composites as visible‐light‐driven catalyst for the photocatalytic application.
Determination of Ibuprofen in Tablets and Human Blood Samples: Effect of Clay in Minimizing Overvoltage of Ibuprofen Oxidation
Authors: Ouafy Hayat El , Hammani Hasna , Farahi Abdelfettah , Lahrich Sara , Bakasse Mina , Mhammedi Moulay Abderrahim El 
Published: October 2019

AbstractIn the current research, clay particles modified graphite electrode (Clay−CPE) was used for the electrocatalytic oxidation of ibuprofen (IBU). This clay was utilized to reduce the distortions of ibuprofen oxidation peak shape and for a better signal to noise ratio. The surface characterization of the clay and their activity toward IBU oxidation were studied by electrochemical methods in particular: cyclic voltammetry, Tafel plots and electrochemical impedance spectroscopy. The number of the electrons, rate constant and kinetic parameters related to ibuprofen oxidation were calculated. The ibuprofen peak gets more symmetrical in the presence of clay giving a detection limit (LOD) of 8.35×10−7 mol L−1 (3Sb/M) using differential pulse voltammetry. The main practical applicability of the modified electrode was explored by determining ibuprofen in tablets and human blood samples.
Polyethylene‐Glycol‐ (PEG‐400) Mediated Environmentally Benign Protocol for the Synthesis of Pyrrolo[1,2‐a]quinoxalines from Benzyl Amines at Room Temperature
Authors: Patil Bhausaheb N. , Lade Jatin J. , Pardeshi Sachin D. , Patil Prashant , Chaskar Atul C. 
Published: October 2019

AbstractA metal‐free, adorable, cascade protocol for the synthesis of pyrrolo[1,2‐a]quinoxalines at room temperature using benzylamine derivatives and 1‐(2‐aminoaryl)pyrrole has been performed. This synthetic protocol involves oxidation of benzylamine derivatives into respective aldehydes followed by condensation with 1‐(2‐aminoaryl)pyrrole in PEG‐400 as a green and reusable solvent using K2S2O8 as an oxidant. The transition metal free as well as ligand free synthesis along with broad substrate scope, wide functional group tolerance and good to excellent yield of products makes it environmentally and economically viable.
Etidronic Acid Promoted Sequential One‐Pot Strategy for the Synthesis of 1H‐Imidazo[1,2‐b]pyrazoles: A Green Catalyst for Groebke‐Blackburn‐Bienaymé Reaction
Authors: Vilapara Kalpesh V. , Gami Sagar P. , Gadara Shobhna A. , Naliapara Yogesh T. 
Published: October 2019

AbstractA development of Groebke‐Blackburn‐Bienaymé (GBB) reaction was shown by the application of Etidronic acid as a green catalyst. A number of 1H‐imidazo[1,2‐b]pyrazoles derivatives were prepared via multicomponent GBB reaction in one pot sequential steps by the condensation of 5‐amino‐1H‐pyrazole, aldehyde and isonitrile. Here, we have demonstrated the development of GBB protocol by the utility of Etidronic acid in milder reaction medium to modify and simplify the existing synthetic strategies that removes hazardous acids, toxic solvents and drastic conditions with sustainable product yields and purity.
Navigating geographic and cultural distances in international expansion: The paradoxical roles of firm size, age, and ownership
Authors: Li Yu , Zhang Yan A. , Shi Wei 
Published: October 2019

AbstractResearch SummaryWhile geographic and cultural distances deter firms' international expansion, they do so via different mechanisms, such that firms with advantages in overcoming one‐dimension may face disadvantages in overcoming the other. Larger, older, and state‐owned firms have better access to resources in their home countries than smaller, younger, and non‐state‐owned firms, and thus are less concerned about the high operating costs associated with larger geographic distances. However, they are less adaptable to culturally distant countries and thus are more concerned about larger cultural distances. We propose that firm size, age, and state ownership weaken the deterrent effect of geographic distance while amplifying the deterrent effect of cultural distance. Results using data on Chinese firms' location choices of foreign direct investments in 2001–2013 support our predictions.Managerial SummaryA key decision that managers need to make in expanding overseas is the foreign location choice. Although managers generally refrain from expanding to geographically and culturally distant countries, the importance of geographic and cultural distances in their consideration varies across firms, which tend to differ in resource endowment and adaptability. Because larger, older, and state‐owned firms are better positioned to absorb additional operating costs but are less adaptable to foreign countries' local environments than smaller, younger, and non‐state‐owned firms, the deterrent effect of geographic distance (cultural distance) is weaker (stronger) for the former than for the latter. Our findings show that foreign countries that seem to be good fits when considering geographic distance may be misfits when considering cultural distance, and vice versa.
Biosorption in der Anwendung zur Reinigung von Kartoffelstärkeabwässern
Authors: Kintzel A. 
Published: October 2019

ZusammenfassungEs werden Laboratoriumsversuche zur Reinigung des Abwassers aus der Kartoffelstärkefabrikation mit Belebtschlamm beschrieben. Das Biosorptionsverfahren ist für diesen Zweck besonders geeignet. Der Reinigungsprozeß unter Anwendung der Biosorption dauert 2½ Stunden und ergibt eine etwa 90% ige Senkung des BSB5‐Wertes.
Molecular association of starch at high temperature
Authors: Sterling By Cl. 
Published: October 2019

SummaryA survey of native starches has shown that a high amylose‐containing corn starch and the starch of wrinkled pea (also with high amylose content) are characterized by the “B” X‐ray diffraction pattern. Starch gels which have been held and dried at 20 °C also exhibit a “B” pattern. Gels held and dried at 70 °C. tend to have a “C” pattern, with variations. These latter gels are less dispersible than gels of 20 °C. The evidence indicates a strong molecular association in starch gels which are held at high temperatures. Basic structural differences in molecules of different varieties of starch in high temperature gels are indicated by their varying crystalline forms.
Zur Frage eines mehrsprachigen Wörterbuches auf dem Gebiet der Stärke
Authors: Ulmann M. 
Published: October 2019

ZusammenfassungMehrsprachige Fachwörterbücher sind ein wichtiges Hilfsmittel für eine internationale fachliche Verständigung, und auch auf dem Stärkegebiet wäre ein solches Fachwörterbuch sehr erwünscht. Erschwerend wirkt sich häufig auch auf dem Gebiet der Stärke der Mangel an klaren Begriffsdefinitionen aus, was mit für die Schwierigkeiten verantwortlich zu machen ist, die leicht bei einer Verständigung in verschiedenen Sprachen, so auch bei Übersetzungen, auftreten. Seit einigen Jahren findet man internationale Bestrebungen zur Schaffung mehrsprachiger Fachwörterbücher für die verschiedensten Gebiete. In den Aufgabenbereich der UNESCO gehört die Beratung in Angelegenheiten der Wörterbücher, die Sorge um wissenschaftliche Dokumentation, Terminologie und Verbesserung von Übersetzungen. Das Technische Komitee TC 37 der ISO befaßt sich dagegen in der Hauptsache mit der Normung von Terminologien; es lenkt und berät die an Fachterminologien arbeitenden Organisationen.Vorbereitende Arbeiten zur Schaffung eines mehrsprachigen Fachwörterbuches (deutschenglischrussisch) auf dem Stärkegebiet sind von der Abteilung für Stärkeforschung des Institutes für Ernährung der Deutschen Akademie der Wissenschaften zu Berlin durch Anlage einer mehrsprachigen Fachwortsammlung geleistet worden. Es bedarf aber einer kritischen Gemeinschaftsarbeit eines möglichst großen Kreises von Fachleuten auf dem Gebiet der Stärke und seiner Nebengebiete, um die zahlreichen Definitions‐ und Normungsfragen zu klären, und um zu einem allen Anforderungen genügenden, mehrsprachigen Wörterbuch auf dem Gebiet der Stärke zu kommen.
Neuere Beiträge zur Chemie der Stärkefraktionen VI
Authors: Holló J. , Szejtli J. , László E. 
Published: October 2019

ZusammenfassungIm Zuge unserer Untersuchungen wurde festgestellt, daß das polarographische Sauerstoffmaxima‐dämpfungsvermögen auch in der Stärkeforschung Anwendung finden kann. Die Kennlinie der Maximadämpfung der Stärke wurde mathematisch auf Grund der Langmuirschen Isotherme beschrieben. Es wurde untersucht, in welcher Weise der Sauerstoffgehalt der Lösung die obige Isotherme modifiziert. In der vorliegenden Arbeit wurde das Maximadämpfungsvermögen in bezug auf die folgenden Gebiete der Stärkeforschung besprochen:

Zur Untersuchung des Verlaufes und des Mechanismus der Verkleisterung,
zur Untersuchung der sauren Hydrolyse,
zur Untersuchung der Retrogradation.
Beurteilung der Inversionswirkung von Stärkesirupen vom Standpunkt der Bonbonerzeuger
Authors: Zelenka S. , Rašper V. , Paulu M. 
Published: October 2019

SchlußfolgerungBeim Vergleich beider Methoden, welcher sich der Bonbonerzeuger zur Beurteilung des Stärkesirups bedient, d. h. der Bestimmung des Inversionsvermögens (IV) und des Inversionsfaktors (IF), zeigte sich, daß die Beziehung zwischen diesen Werten nicht genügend nachweisbar ist. Analysen von direkt im Betriebe erzeugten Bonbonmassen ergaben, daß die Menge des gebildeten Invertzuckers in einer direkten Beziehung zu dem IV des Sirups steht. Da aber keine verläßliche Beziehung zwischen den Werten des IV und des IF nachgewiesen werden konnte, kann man auf Grund des IF nicht schließen, wie stark die katalytische Wirkung des Stärkesirups auf die angeführte Inversion sein wird. Die genaue Bestimmung des IF wird durch den nicht genügend deutlichen Farbumschlag der Indikatoren bei der Bestimmung der Titrationswerte erschwert und dies hauptsächlich bei gelb gefärbten Sirupen. Die Bestimmung des IV als Objektivierung der Bonbonprobe ist zwar umständlicher und erklärt nicht die Ursache der Inversionswirkung des Sirups, gibt aber dem Bonbonhersteller einen sehr verläßlichen Wert, da diese Bestimmung komplex die Wirkung der Faktoren auswertet, welche sich an der Bildung des Invertzuckers beteiligen und dabei eigentlich die Qualität der Hartkaramellen in bezug auf ihre Lagerfähigkeit beeinflussen. Zu diesen Faktoren ist es nötig, auch den katalytischen Einfluß der Kationen der Schwermetalle und der Erdalkalien einzu‐beziehen, denn diese erhöhen erheblich das IV.Endlich wurde der puffernde Charakter der Stärkesirupe mit einem höheren scheinbaren Gehalt an P2O5 resp. einem höheren Phosphatäquivalent (PE) überprüft, welches sich günstig bei der Ansäuerung der noch nicht genügend gekühlten Bonbonmasse auswirken kann.
Crystallinity of potato starch
Authors: Sterlin Cl. 
Published: October 2019

SummaryMethods have been described for the determination of the crystallinity of potato starch, based upon the X‐ray diffraction technique of Hermasns and Weidinger. The crystallinity of air‐dry native potato starch is 21%; that of the moistened, natioe starch is 28%. Air‐dry Lintnerized potato starch is 27% crystalline while the moistened, Lintnerized starch has a crystallinity of 34%. Crystallinity values, based upon other data, have, been computed; these fall within the limits of the determinations by the X‐ray method and help confirm those data.
L'eau de sorption de l'amidon: Etude par spectrologie hertzienne
Authors: Guilbot A. , Charbonniere R. , Abadie P. , Girard† P. 
Published: October 2019

ZusammenfassungWir zeigten die Möglichkeiten der Hertzschen Spektrologie zur Untersuchung eines Wasser‐Makromolekül‐Systems. Es scheint angebracht, besonders auf die Notwendigkeit hinzuweisen, die dielektrische Untersuchung in einem sehr weiten Frequenzbereich durchzuführen, sonst gelangt man nur zu fragmentarischen Ergebnissen, die die Schlußfolgerungen verfälschen können (17).Einige Hypothesen verlangen genauere Bestätigungen, und die durchgeführte Spektralanalyse stellt in Anbetracht unserer Kenntnisse über feste Stoffe nur eine grobe Annäherung dar. Dennoch erweist sich die Methode von jetzt an als sehr wertvoll, da sie gestattet, die Größenordnung von unter verschiedenen Zuständen gebundenen Wassermengen, charakterisiert durch die mittlere Aktivierungsenergie, zu bestimmen. Nach unserer Kenntnis wurden bisher von den übrigen schon angewandten Untersuchungstechniken keine Angaben dieser Art geliefert. Die Resultate der Hertzschcn Spektrologie treffen sich in bestimmten Punkten mit denen der anderen Untersuchungstechniken: im besonderen die bemerkenswerten Wassergehalte von 9–10% (19, 21) und 15–16% (11) und vielleicht der Wassergehalt der etwa dem Sorptionsgleichgewicht des bei 20° C gesättigten Wasserdampfes entspricht (21).Die Bindung des Wassers in makromolekularen Ketten wie die der Stärkekomponenten bleibt weiterhin wegen der Kontinuität und dem gleichzeitigen Vorhandensein verschiedener Typen von Wasser schwierig zu untersuchen. Nichtveröffentlichte Sorptionsresultate und augenblicklich durchgeführte Untersuchungen mit Hilfe der Beugung der Röntgenstrahlen lassen voraussehen, daß es durch Kombination der Hertzschen Spektrologie mit anderen physikochemischen Methoden möglich sein wird, genauere Kenntnisse zumindest über die Art der Bindung der ersten in der Stärke vorhandenen 15% Wasser zu gewinnen.