bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study on the changes in the East Asian precipitation in the mid‐1990s using a high‐resolution global downscaled atmospheric data set
Authors: Chang Eun‐Chul , Yeh Sang‐Wook , Hong Song‐You , Kim Jung‐Eun , Wu Renguang , Yoshimura Kei 
Published: January 2014

AbstractA high‐resolution global atmospheric data set (DA126) is used to understand the East Asian summer precipitation variability. It is found that a fine resolution of the DA126 precipitation data is able to reveal the detailed structures of the rainfall variability over East Asia and southern China in comparison with global analysis precipitation data sets such as the Climate Prediction Center Merged Analysis of Precipitation (CMAP). The first two empirical orthogonal functions (EOFs) of the DA126 precipitation data over East Asia accurately reflect a decadal shift in rainfall over southern China in the mid‐1990s. Furthermore, the first EOF‐related precipitation of the DA126 is related to the tropical Pacific sea surface temperature (SST) variability (i.e., El Niño/Southern Oscillation), and the second EOF‐related precipitation is associated with the Indian Ocean SST variability. Consequently, the tropical Pacific and the Indian Ocean SSTs have different associations with the East Asian monsoon precipitation variability. However, it is difficult to find such a relationship in the first two EOFs of the CMAP data set over East Asia. Using the DA126 precipitation data set, our further analysis indicates that warming of both the tropical Pacific and the Indian Ocean causes an increase in the rainfall anomaly over southern China after the mid‐1990s, which results in a decadal shift in the rainfall anomaly after the mid‐1990s. In addition, the first EOF‐related precipitation is associated with both the Pacific‐Japan‐like (PJ‐like) pattern and the Eurasian‐like pattern. In contrast, the second EOF‐related precipitation is only associated with the PJ‐like wave trains from the western Pacific to East Asia.
Fluorometrischer Nachweis von Fluorid in wässriger Lösung mittels Teststreifen und einem BODIPY‐Wasserstoffbrückenrezeptor‐Konjugat
Authors: Ashokkumar Pichandi , Weißhoff Hardy , Kraus Werner , Rurack Knut 
Published: January 2014

AbstractDie Bestimmung von biologisch relevanten Anionen wie Fluorid ist eine wichtige Aufgabe in der analytischen Chemie, insbesondere im Hinblick auf Zahnpflege und Osteoporose. Es gibt zwar eine große Zahl an Fluoridsonden, ihre Anwendbarkeit unter umweltrelevanten Bedingungen ist aber auf wenige Beispiele beschränkt. Um dieses Ziel zu erreichen, wurden BODIPY‐Amidothioharnstoff‐Farbstoffe mit unterschiedlicher Wasserstoffbrückendonorstärke entwickelt, wovon die H‐azideste Verbindung (1 c) anorganisches F− (aus NaF) in DMSO/H2O (1:1, v/v) mit 0.01 ppm Empfindlichkeit durch Fluoreszenzlöschung über einen photoinduzierten Elektronentransfer nachweisen kann. Einbettung der Sonde und eines Referenzfarbstoffs in einen Teststreifen‐Assay mit einem tragbaren “Lateral‐Flow”‐Fluoreszenzlesegerät ermöglichte die Bestimmung von F− in wässrigen Lösungen wie versetzten Wasserproben und Zahncremeextrakten mit interner Referenzierung bis zu einer Nachweisgrenze von 0.2 ppm.
Unusual Hafnium–Pyridylamido/ERn Heterobimetallic Adducts (ERn=ZnR2 or AlR3)
Authors: Rocchigiani Luca , Busico Vincenzo , Pastore Antonello , Talarico Giovanni , Macchioni Alceo 
Published: January 2014

AbstractNMR spectroscopy and DFT studies indicate that the Symyx/Dow Hf(IV)–pyridylamido catalytic system for olefin polymerization, [{N−,N,CNph−}HfMe][B(C6F5)4] (1, Nph=naphthyl), interacts with ERn (E=Al or Zn, R=alkyl group) to afford unusual heterobimetallic adducts [{N−,N}HfMe(μ‐CNph)(μ‐R)ERn−1][B(C6F5)4] in which the cyclometalated Nph acts as a bridge between Hf and E. 1H VT (variable‐temperature) EXSY NMR spectroscopy provides direct evidence of reversible alkyl exchanges in heterobimetallic adducts, with ZnR2 showing a higher tendency to participate in this exchange than AlR3. 1‐Hexene/ERn competitive reactions with 1 at 240 K reveal that the formation of adducts is strongly favored over 1‐hexene polymerization. Nevertheless, a slight increase in the temperature (to >265 K) initiates 1‐hexene polymerization.
Well‐Defined, Nanometer‐Sized LiH Cluster Compounds Stabilized by Pyrazolate Ligands
Authors: Stasch Andreas 
Published: January 2014

AbstractThe assembly of well‐defined large cluster compounds of ionic light metal hydrides is a synthetic challenge and of importance for synthesis, catalysis, and hydrogen storage. The synthesis and characterization of a series of neutral and anionic pyrazolate‐stabilized lithium hydride clusters with inorganic cores in the nanometer region is now reported. These complexes were prepared in a bottom‐up approach using alkyl lithium and lithium pyrazolate mixtures with silanes in hydrocarbon solutions. Structural characterization using synchrotron radiation revealed isolated cubic clusters that contain up to 37 Li+ cations and 26 H− ions. Substituted pyrazolate ligands were found to occupy all corners and some edges for the anionic positions.
Dinuclear Ruthenium(II) Complexes as Two‐Photon, Time‐Resolved Emission Microscopy Probes for Cellular DNA
Authors: Baggaley Elizabeth , Gill Martin R. , Green Nicola H. , Turton David , Sazanovich Igor V. , Botchway Stanley W. , Smythe Carl , Haycock John W. , Weinstein Julia A. , Thomas Jim A. 
Published: January 2014

AbstractThe first transition‐metal complex‐based two‐photon absorbing luminescence lifetime probes for cellular DNA are presented. This allows cell imaging of DNA free from endogenous fluorophores and potentially facilitates deep tissue imaging. In this initial study, ruthenium(II) luminophores are used as phosphorescent lifetime imaging microscopy (PLIM) probes for nuclear DNA in both live and fixed cells. The DNA‐bound probes display characteristic emission lifetimes of more than 160 ns, while shorter‐lived cytoplasmic emission is also observed. These timescales are orders of magnitude longer than conventional FLIM, leading to previously unattainable levels of sensitivity, and autofluorescence‐free imaging.
Reversible Single‐Crystal‐to‐Single‐Crystal Photochemical Formation and Thermal Cleavage of a Cyclobutane Ring
Authors: Kole Goutam Kumar , Kojima Tatsuhiro , Kawano Masaki , Vittal Jagadese J. 
Published: January 2014

AbstractA [2+2] cycloaddition reaction has been observed in a number of solids. The cyclobutane ring in a photodimerized material can be cleaved into olefins by UV light and heat. The high thermal stability of the metal–organic salt K2SDC (H2SDC=4,4’‐stilbenedicarboxylic acid) has been successfully utilized to investigate the reversible cleavage of a cyclobutane ring. The two polymorphs of K2SDC undergo reversible cyclobutane formation by UV light and cleavage by heat in cycles. Of these, one polymorph retains its single‐crystal nature during the reversible processes. Polymorphs are known to show different physical properties and chemical reactivities. This work reveals that the retention of single‐crystal nature is strongly associated with the packing of molecules, which is controlled by kinetics and thermodynamics. The photoemissive nature of the products makes this as a promising material for photoswitches and optical data storage devices.
Test‐Strip‐Based Fluorometric Detection of Fluoride in Aqueous Media with a BODIPY‐Linked Hydrogen‐Bonding Receptor
Authors: Ashokkumar Pichandi , Weißhoff Hardy , Kraus Werner , Rurack Knut 
Published: January 2014

AbstractThe measurement of biologically relevant anions, such as fluoride, is an important task in analytical chemistry, in particular, for dental health and osteoporosis. Although a large number of fluoride probes are known, the applicability under relevant conditions is limited to a few examples. To improve this situation, BODIPY‐amidothiourea dyes with varying hydrogen‐bond donating strengths were developed, the most H‐acidic of which (1 c) could detect F− from an inorganic source (NaF) in 50 % aqueous solution (DMSO/water 1:1, v/v) with 0.01 ppm sensitivity through selective fluorescence quenching by a photoinduced electron‐transfer (PET) process. Use of the probe and a reference dye with a test‐strip assay and a portable and rapidly recording lateral‐flow fluorescence reader made determination of F− in neat aqueous solutions, such as spiked water samples and toothpaste extracts, possible in a self‐referenced manner, achieving a detection limit of 0.2 ppm.
Allylic Functionalization of Unactivated Olefins with Grignard Reagents
Authors: Bao Hongli , Bayeh Liela , Tambar Uttam K. 
Published: January 2014

AbstractNew advances in the functionalization of unactivated olefins with carbon nucleophiles have provided more efficient and practical approaches to convert inexpensive starting materials into valuable products. Recent examples have been reported with stabilized carbon nucleophiles, tethered carbon nucleophiles, diazoesters, and trifluoromethane donors. A general method for functionalizing olefins with aromatic, aliphatic, and vinyl Grignard reagents was developed. In a one‐pot process, olefins are oxidized by a commercially available reagent to allylic electrophiles, which undergo selective copper‐catalyzed allylic alkylation with Grignard reagents. Products are formed in high yield and with high regioselectivity. This was utilized to synthesize a series of skipped dienes, a class of compounds that are prevalent in natural products and are difficult to synthesize by known allylic alkylation methods.
Preparations and properties of a high performance semicrystalline copolyimide and composites reinforced with glass fiber
Authors: Wang Wei , Zhou Hongwei , Chen Dongfeng , Wu Meimei , Liu Yuntao , Chen Chunhai 
Published: January 2014

ABSTRACTA semicrystalline copolyimide derived from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (s‐BPDA), 1,3‐bis‐(4‐aminophenoxy)benzene (TPER), and 4,4′‐oxydianiline (4,4′‐ODA), end capped with phthalic anhydride (PA), was synthesized. Glass fiber reinforced composite was also prepared by impregnating powdery glass fiber with poly(amic acid) followed by solution imidization techniques. This copolyimide displayed a glass transition temperature of 202°C and a melting temperature of 373°C by differential scanning colorimeter (DSC). Crystallization and melting behaviors were investigated under nonisothermal and isothermal crystallization conditions. Double exothermic peaks were found by DSC when the copolyimide was cooled from the melt and multiple melting behaviors can be observed after the coployimide had been isothermally crystallized at different temperatures. Mechanical properties were investigated by dynamical mechanical analysis (DMA) and tensile experiments. The samples were cured at different temperatures and then tested at different temperatures. Results indicated that the copolyimide and the composite showed excellent mechanical properties. Additionally, this copolyimide also showed lower melt viscosity by rheological analysis. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40345.
Ultrafine cellulose triacetate mats electrospun by using co‐solvent of DMSO/chloroform system
Authors: Lan Tian , Shao Zi‐Qiang , Wang Wen‐Jun , Wang Fei‐Jun , Zhang Da‐Lun , Wang Jian‐Quan , Liu Yan‐Hua , Kong Lin‐Lin 
Published: January 2014

ABSTRACTCellulose triacetate (CTA) nanofiber nonwoven mats were continuously electrospun by using mixed solvent of DMSO/chloroform system. The size and morphology of CTA nanofibers were investigated. It was found that CTA fibers with diameters in the range of 98 nm–1.81 μm were obtained from 8 wt % CTA solutions in 1 : 1, 3 : 2, 2 : 1, 3 : 1, 5 : 1 and 7 : 1 (v/v) DMSO/chloroform. The average diameter of CTA nanofiber was decreased and size distribution was narrowed with increasing the DMSO content in the mixed solvent. Smooth and uniform nanofibers with mean diameters of about 260 nm could be obtained from a solution of CTA in the binary system DMSO/chloroform 5 : 1(v/v) at a polymer concentration of 8 wt %. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40373.
Ab initio emulsion RAFT polymerization of vinylidene chloride mediated by amphiphilic macro‐RAFT agents
Authors: Yang Jie , Bao Yongzhong , Pan Pengju 
Published: January 2014

ABSTRACTAn amphiphilic copolymer poly(acrylic acid)‐block‐poly(styrene) (PAA‐b‐PS) with a trithiocarbonate reactive group was used in the ab initio reversible addition‐fragmentation chain transfer (RAFT) emulsion polymerization of vinylidene chloride (VDC). The fast polymerization and high conversion were achieved. The parameters for a good control over the formation of well‐defined PAA‐b‐PS‐b‐PVDC amphiphilic block copolymers and self‐stabilized latexes were identified. To improve the emulsion stability and prevent the desorption of water‐soluble initiating radicals, the acid groups of PAA‐b‐PS were neutralized by NaOH at the later stage of polymerization. The PAA‐b‐PS‐b‐PVDC block copolymer with a high molar mass of 30 kg mol−1 and the stable latex with 30 wt % solid content was obtained. The kinetics of RAFT emulsion copolymerization of VDC in a living manner was first investigated. The as‐prepared PAA‐b‐PS‐b‐PVDC latex particles were further used as seeds in the emulsion polymerization of styrene, enabling the preparation of novel PAA‐b‐PS‐b‐PVDC‐b‐PS tetra‐block copolymers with a molar mass of 76 kg mol−1 and a relatively low molecular weight distribution of 1.6. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40391.
Spray‐drying microencapsulation of β‐carotene by soy protein isolate and/or OSA‐modified starch
Authors: Deng Xi‐Xiang , Chen Zhong , Huang Qiang , Fu Xiong , Tang Chuan‐He 
Published: January 2014

ABSTRACTMicroencapsulation is an effective strategy to improve the storage stability of β‐carotene. This article investigated the potential and effectiveness of soy protein isolate (SPI) and octenylsuccinic anhydride‐modified starch (MS), alone or in combination (1:1, w/w), to encapsulate β‐carotene by spray drying. The results indicated that the microcapsule with MS exhibited much lower encapsulation efficiency (NE) and poorer dissolution behavior, but much better redispersion behavior, than that with SPI or its blends with MS. The NE was basically unaffected by total solid content (TC) or core/wall ratio; increasing the TC impaired the dissolution and/or redispersion behavior. The dispersion behavior was closely associated with the morphology of the microcapsules. The encapsulated β‐carotene suffered a progressive loss upon storage under high humid or temperature environment, but it exhibited extraordinary stability at low temperatures (e.g., 4°C). The β‐carotene degradation was independent of sunlight. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40399.
Study of polyarylene ether nitrile terminated with phthalonitrile/hybrid Fe3O4 nanospheres composites by orthogonal experiments
Authors: Tong Lifen , Liu Mengdie , Long Ya , Liu Xiaobo 
Published: January 2014

ABSTRACTA novel series of composites of polyarylene ether nitrile terminated with phthalonitrile (PEN‐t‐Ph) filled with hybrid Fe3O4 nanospheres (h‐Fe3O4) was prepared via in situ composition. Based on the cross‐linking interactions between the phthalonitrile at the end of PEN‐t‐Ph molecular chains and the phthalonitrile on the surface of h‐Fe3O4 particles to form phthalocyanine ring, it was shown that the PEN‐t‐Ph/h‐Fe3O4 system had superior interfacial compatibility and the h‐Fe3O4 particles were locked in the matrix resin. These results had been confirmed by scanning electron microscope analysis. By orthogonal experiments and statistic analysis, the optimal conditions of cure temperature, type of h‐Fe3O4 and content of h‐Fe3O4 had been determined. Meanwhile, the results of range analysis and variance analysis indicated that the cure temperature had great effects on the thermal properties. Thermal studies revealed that the glass transition temperature of PEN‐t‐Ph/h‐Fe3O4 cured at 320°C was 214.7°C, increased by about 40°C compared to the PEN‐t‐Ph/h‐Fe3O4 without heat treatment, and the temperature corresponding to the weight loss of 5 wt % was increased by about 20°C. Mechanical measurements indicated that PEN‐t‐Ph/h‐Fe3O4 cured at 320°C possesses excellent mechanical properties with tensile strength of 93.33 MPa and tensile modulus of 2414.05 MPa, 9.91 MPa, 355.76 MPa higher than pure PEN‐t‐Ph film cured at 320°C, and 13.26 MPa, 397.90 MPa higher than PEN‐t‐Ph/h‐Fe3O4 without heat treatment. Most importantly, the presence of h‐Fe3O4 particles endows PEN‐t‐Ph/h‐Fe3O4 system with good magnetic property. Thus, PEN‐t‐Ph/h‐Fe3O4 cured at 320°C may have potential applications in field of magnetic materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40418.
Self‐Assembly of Chiral Propeller‐like Supermolecules with Unusual “Sergeants‐and‐Soldiers” and “Majority‐Rules” Effects
Authors: Nie Bo , Zhan Tian‐Guang , Zhou Tian‐You , Xiao Ze‐Yun , Jiang Guo‐Fang , Zhao Xin 
Published: January 2014

AbstractChiral amplification is an interesting phenomenon in supramolecular chemistry mainly observed in complicated systems in which cooperative effect dominate. Herein, chiral, supramolecular, propeller‐like architectures have been constructed through coassembly of an achiral disk‐shaped molecule and chiral amino acid derivatives driven by intermolecular hydrogen bonding. Both the “sergeants‐and‐soldiers” principle and “majority‐rules” effect are applicable in these discrete four‐component supermolecules, which are the simplest supramolecular system ever reported that exhibit chiral amplification.
Finite‐Horizon ε‐Optimal Tracking Control of Discrete‐Time Linear Systems Using Iterative Approximate Dynamic Programming
Authors: Tan Fuxiao , Luo Bin , Guan Xinping 
Published: January 2014

AbstractIn this paper, we propose a finite‐horizon neuro‐optimal tracking control strategy for a class of discrete‐time linear systems. In applying the iterative approximate dynamic programming (ADP) algorithm to determine the optimal tracking control law for linear systems, we need finite iterations to obtain the result in practical applications, instead of infinite iterations. An ε‐error bound is introduced into the ADP algorithm to determine the number of iteration steps. The approximation optimal tracking control law will approach the solution of the Hamilton‐Jacobi‐Bellman (HJB) equation through a self‐adaptive iteration within the given value of ε‐error bound. ε error bound is used to stop the iteration process. So, we can obtain the ε‐approximation tracking control law in a finite number of iterations. Nevertheless, different ε will produce different control performances. Furthermore, we will find an optimal ε error bound, which can obtain optimal performance of the ADP algorithm on the basis of the controlled system tracking the desired trajectory. One example is included to complete the ADP algorithm under different error bounds. From the simulation results, we can find the optimal ε error bound. Finally, the simulation validates the efficiency of the proposed algorithm.
Robust Stability and Stabilization of Positive Interval Systems Subject to Actuator Saturation
Authors: Zhang Ji‐Shi , Deng Zeguan , Wang Yan‐Wu 
Published: January 2014

AbstractThis paper addresses the stabilization problem for a class of uncertain positive linear systems (PLSs) in the presence of saturating actuators. The objective is to obtain sufficient conditions for the robust stability of PLSs and to design robust state feedback control laws such that the closed‐loop uncertain system is asymptotically stable and positive at the origin with a large domain of attraction. Several sufficient conditions for robust stabilization and positivity are derived via the Lyapunov function approach and convex analysis method for both the discrete‐time and the continuous‐time cases, respectively. The state feedback controller design and the estimation of the domain of attraction are presented by solving a convex optimization problem with linear matrix inequalities (LMIs) constraints. A numerical example is given to show the effectiveness of the proposed methods.
Tensor Product Model Transformation Based Control and Synchronization of a Class of Fractional‐Order Chaotic Systems
Authors: Kuntanapreeda Suwat 
Published: January 2014

AbstractFractional‐order chaotic systems are the complex systems that involve non‐integer order derivatives. In this paper, tensor product (TP) model transformation‐based controller design for control and synchronization of a class of the fractional‐order chaotic systems is investigated. We propose a novel linear matrix inequality (LMI)‐based stabilization condition for fractional‐order TP models with a controller derived via a parallel distributed compensation (PDC) structure. In the controller design, the controlled system first is transformed into a convex state‐space TP model using the TP model transformation. Based on the transformed TP model, the controller is determined by solving the proposed LMI condition. To the best of our knowledge, this is the first investigation of TP model transformation based design in fractional‐order systems. Several illustrative examples are given to demonstrate the convenience of the proposed LMI condition and the effectiveness of the controller design.
Chiral separability of boron cluster species studied by screening approaches utilizing polysaccharide‐based chiral stationary phases
Authors: Mangelings D. , Vander Heyden Y. , Vespalec R. 
Published: January 2014

ABSTRACTIn this study, the screening steps of chiral separation strategies with polysaccharide‐based chiral stationary phases were applied on boron cluster compounds in normal‐phase liquid chromatography (NPLC) and polar organic solvents chromatography (POSC). Since the screening steps were initially developed to analyze organic compounds, their applicability for boron clusters was investigated. Overall, the screening steps in NPLC were applicable for the separation of zwitterions, while for anions mostly no elution was observed. A hypothesis for the latter behavior is precipitation of anions in the nonpolar mobile phases. Ten out of 11 compounds could be partially or baseline separated on the NPLC screening systems. In POSC, all zwitterions were separated on at least one of the screening systems, with an overall lower retention as in NPLC. Anions were detected but not separated in the majority of the experiments. Also their retention on the chiral stationary phases was very limited. This study showed that the chiral discrimination potential of chemically modified polysaccharides is meaningful for chiral separations of structurally chiral boron cluster species, but needs further systematic research, in which recognition mechanisms should be further explored. In addition, some unusual peaks also indicated that conditions with a high separation efficiency must first be searched for some of the tested systems. Copyright © 2014 John Wiley & Sons, Ltd.
A geometric approach to animating thin surface features in smoothed particle hydrodynamics water
Authors: Jang Taekwon , Noh Junyong 
Published: January 2014

AbstractWe propose a geometric approach to animating thin surface features of smoothed particle hydrodynamics‐based water. Explicit interparticle connections are created among smoothed particle hydrodynamics particles to approximate the geometries of thin surfaces while addressing the issue of unresolved surface areas. The deformations measured on the connections actuate the animations of the surfaces by disconnecting the stretched and bent connections. The reconstruction of thin surfaces and the accuracy of the animation are improved by adding auxiliary particles over the connections via Poisson‐disk sampling. Copyright © 2014 John Wiley & Sons, Ltd.