论《切韵》的审音原则

《切韵》采用了"从分"的审音原则。本文对《切韵·序》关键词"捃选精切"之"切"的释义予以补正,指出《切韵》书题的双层含义。利用南北朝、隋代诗文用韵,验证《切韵》审音"从分"的原则,分析该原则实现的三种途径。根据《颜氏家训·音辞》的全部韵辨例及"开皇论韵"史实,阐明《切韵》审音原则之源。"从分"的兼容机制使《切韵》获得了极大的兼容性,《切韵》系韵书及之后韵书的演进,与这一机制有关。基于"从分"的审音原则,提出了《切韵》语音性质的新观点。

Subclasses of Meromorphic Multivalent Functions

In this paper we introduce some new subclesses of meromorphic multivalent functions. Inclusion relations between these classes, the class preserving integral operators and coefficient estimates are obtained.

Tunable activity of electrocatalytic CO dimerization on strained Cu surfaces:Insights from ab initio molecular dynamics simulations

Controlling catalytic activities through surface strain engineering remains a hot topic in electrocatalysis studies.Herein,ab initio molecular dynamics(AIMD)simulation associated with free energy sampling technology were performed to study the energetics of the key step of producing C2 products in electrocatalytic reduction of CO or CO_(2),i.e.CO dimerization,on strained Cu(100)with an explicit aqueous solvent model.It is worth mentioning that when compressive strain reaches a certain extent,the surface of Cu(100)will undergo reconstruction.We showed that,from tensile to compressive strain,the free energy barrier of CO dimerization decreased,suggesting that the activity of CO dimerization increases.It was also found that some of the reconstructed surfaces showing the lowest free energy barriers but might be less stable can be stabilized in the presence of adsorbed O or CO.Upon detailed quantitative analysis on the charges of surface Cu atoms,we found that the free energy barriers were strongly correlated with the charge of Cu atoms where the OCCO intermediate adsorbs.When the surfaces structures of Cu(100)were altered under compressive strain,the electronic structure of surface Cu atoms was monitored and thus the activity of electrocatalytic CO dimerization can be tuned.

Exponential Synchronization of Master-Slave Lur'e Systems via Intermittent Time-Delay Feedback Control

This paper concerns with the master-slave exponential synchronization analysis for a class of general Lur'esystems with time delay.Different from the previous methods based on the differential inequality technique, a newapproach is proposed to derive some new exponential synchronization criteria.The restriction that the control widthhas to be larger than the time delay is removed.This leads to a larger application scope for our method.Moreover, notranscendental equation is involved in the obtained result, which reduces the computational burden.Two examples aregiven to validate the theoretical results.

Density functional investigation on structural and electronic properties of small bimetallic Pb_(n)Ag_(n)(n=2–12)clusters

Structural and electronic properties of PbnAgn(n=2–12)clusters were investigated by density functional theory with generalized gradient approximation at BLYP level in DMol3 program package.The optimized bimetallic PbnAgn(n=2–12)clusters were viewed as the initial structures,then,those were calculated by ab initio molecular dynamics(AIMD)to search possible global minimum energy structures of PbnAgn clusters,finally,the ground state structures of PbnAgn(n=2–12)clusters were achieved.According to the structural evolution of lowest energy structures,Ag atoms prefer gather in the central sites while Pb atoms prefer external positions in PbnAgn(n=2–12)clusters,which is in excellent agreement with experimental results from literature and the application in metallurgy.The average binding energies,HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities,chemical hardnessη,HOMO orbits,LUMO orbits and density of states of PbnAgn(n=2–12)clusters were calculated.The results indicate that the values of HOMO-LUMO gaps,vertical ionization potentials,vertical electron affinities and chemical hardnessηshow obvious odd-even oscillations when n≤5,PbnAgn(n=2–12)clusters become less chemically stable and show insulator-to-metal transition with the variation of cluster size n,PbnAgn(n≥9)cluster are good candidates to study the properties of PbAg alloys.Those can be well explained by the density of states(DOS)distributions of Pb atoms and Ag atoms between–0.5 Ha and 0.25 Ha in PbnAgn(n=2–12)clusters.

Analysis of cumulative handoff delay for graded secondary users in cognitive radio networks

According to the fact that the secondary users＇ delay requirements for data transmission are not unitary in cognitive radio networks, the secondary users are divided into two classes, denoted by SU1 and SU2, respectively. It is assumed that SU1 has a higher priority to occupy the primary users＇ unutilized channels than SU2. A preemptive resume priority M/G/1 queuing network is used to model the multiple spectrum handoffs processing. By using a state transition probability matrix and a cost matrix, the average cumulative delays of SU1 and SU2 are calculated, respectively. Numerical results show that the more the primary user＇s traffic load, the more rapidly the SU2＇s cumulative handoff delay grows. Compared with the networks where secondary users are unitary, the lower the SUI＇s arrival rate, the more obviously both SUI＇s and SU2＇s handoff delays decrease. The admission access regions limited by the maximum tolerable delay can also facilitate the design of admission control rules for graded secondary users.

Dehydroxylation of Glycerol on Pt Surfaces:Ab Initio Molecular Dynamics Study

Glycerol is an important raw material in the chemical industry,and dehydroxylation of glycerol would produce 1,2-propanediol and 1,3-propanediol.Here we studied glycerol dehydroxylation with ab initio molecular dynamics simulations on Pt(111)and Pt(211)surfaces at 453 K.The free energies obtained on Pt show that dehydroxylation is more likely to occur at the terminal carbon than the central carbon,and 1,2-propanediol would be produced preferentially,which is consistent with the selectivity observed experimentally.We found a linear relationship between the free energy barrier and the difference of average distances between O atoms at the initial state and transition state.Although a high correlation between the stability of gaseous glycerol and the number of formed hydrogen bonds is determined from density functional theory calculations,the hydrogen bonds formed within surface structures play a negligible role in determining the free energy barriers of dehydroxylation.

Theoretical Study of 1,3-Dipolar Cycloaddition of Hydrazoic Acid to Substituted Ynamines

The 1,3-dipolar cycloaddition reactions of various substituted ynamines with hydrazoic acid were theoretically investigated with the high-accuracy CBS-QB3 method. Two regioisomers, 4-amine, and 5-amine substituted adducts, were obtained, with the former as the preferred yield. This regioselectivity is rationalized by the frontier molecular orbital theory. The reactivity and synchronicity are enhanced with the increase of the electron-withdrawing character of the substitute on ynamine fragment. The calculations also show that the effect of solvent increases the activation energy, and the reaction becomes even harder in polar solvent.

Hydrogen Promoted Decomposition of Ammonium Dinitramide:an ab initio Molecular Dynamics Study

Thermal decomposition of a famous high oxidizer arnrnoniurn dinitrarnide （ADN） under high temperatures （2000 and 3000 K） was studied by using the ab initio molecular dynamics method. Two different ternperature-dependent initial decomposition mechanisms were observed in the unirnolecular decomposition of ADN, which were the intrarnolecular hydrogen transfer and N-NO2 cleavage in N（NO2） . They were competitive at 2000 K, whereas the forrner one was predominant at 3000 K. As for the rnultimolecular decomposition of ADN, four different initial decomposition reactions that were also ternperature-dependent were observed. Apart from the aforernentioned rnechanisrns, another two new reactions were the interrnolecular hydrogen transfer and direct N-H cleavage in NH4＋. At the temperature of 2000 K, the N-NO2 cleavage competed with the rest three hydrogen-related decomposition reactions, while the direct N-H cleavage in NH4＋ was predominant at 3000 K. After the initial decomposition, it was found that the temperature increase could facilitate the decomposition of ADN, and would not change the key decomposition events. ADN decomposed into small molecules by hydrogen-prornoted simple, fast and direct chemical bonds cleavage without forrning any large intermediates that rnay impede the decomposition. The main decomposition products at 2000 and 3000 K were the same, which were NH3, NO2, NO, N2O, N2, H2O, and HNO2.

Ab initio Molecular Dynamics Study of Adsorption of Hydroxyl Groups on Graphene Surface

Reduced graphene oxide is the precursor to produce graphene in a large scale;however,to date,there has been no consensus on the electronic structure of reduced graphene oxide.In this study,we carried out an ab initio molecular dynamics simulation to investigate the adsorption process of hydroxyl groups on graphene surface.During the adsorption process,the OH group needs to firstly pass through a physical adsorption complex with the OH above the bridge site of two carbon atoms,next to surmount a transition state,then to be adsorbed at the atop site of a carbon atom.With a 5×5 graphene surface,up to 6 hydroxyl groups can be adsorbed on the graphene surface,indicating the concentration coverage of the hydroxyl groups on graphene surface is about 12%.The simulation results show that the negative adsorption energy increases linearly as the number of adsorbed hydroxyl groups increases,and the band gap also increases linearly with the number of adsorbed hydroxyl groups.

Solvation structure and dynamics of Li and LiO_(2)and their transformation in non-aqueous organic electrolyte solvents from first-principles simulations

Density functional theory calculations together with ab initio molecular dynamics(AIMD)simulations have been used to study the solvation,diffusion and transformation of Li^(+)and LiO_(2)upon O_(2)reduction in three organic electrolytes.These processes are critical for the performance of Li-air batteries.Apart from studying the structure of the solvation shells in detail,AIMD simulations have been used to derive the diffusivity and together with the Blue Moon ensemble approach to explore LiO_(2)formation from Li^(+)and O_(2)−and the subsequent disproportionation of 2LiO_(2)into Li_(2)O_(2)+O_(2).By comparing the results of the simulations to gas phase calculations,the impact of electrolytes on these reactions is assessed which turns out to be more pronounced for the ionic species involved in these reactions.

Accurate ab initio Predictions of Ionization Energies and Heats of Formation for Cyclopropenylidene, Propargylene and Propadienylidene

The ionization energies （IEs） of cyclopropenylidene （c-C3H2）, propargylene （HCCCH） and propadienylidene （H2CCC） have been computed using the CCSD（T）/CBS method, which involves the approxixnation to the complete basis set （CBS） limit at the coupled cluster level with single and double excitations plus quasi-perturbative triple excitation effect （CCSD（T））. The zero-point vibrational energy correction, the core-valence electronic correction, the scalar relativistic effect and the high level correction beyond the CCSD（T） excitations have also been made in these calculations. The CCSD（T）/CBS values for the IN（c-C3H2） and IE（HCCCH） of 9.164, 8.987 eV are in good agreement with the experimental values of （9.15±0.03） and （8.96±0.04） eV. The CCSD（T）/CBS calculations yield the IE values of 10.477 and 10.388 eV for the ionization transitions H2CCC→H2CCC^＋ （^2A1, C2v） and H2CCC→H2CCC＋ （^2A＇, Cs）, respectively. On the basis of the Franek-Condon factor consideration, the IE of （10.43±0.02） eV determined in the previous single-photon ionization experiment most likely corresponds to the ionization threshold for the H2CCC→H2CCC^＋（^2A1, C2v） transition. Although the precision of the experimental IN measurements fpr c-C3H2, HCCCH, and H2CCC is insufficient to pin down the accuracy of the theoretical calculations to better than ±30 meV, the excellent agreement between the experimental and theoretical IE values observed in the present study indicates that the CCSD（T）/CBS calculations together with high-order correlation corrections are capable of yielding reliable IE predictions for simple hydrocarbon carbenes and bi-radicals. We have also reported the heats of formation at 0 K （△H^of0） and 298 K （△H^of298）for c-C3H2/c-C3H2^＋, HCCCH/HCCCH^＋, and H2CCC/H2CCC^＋, The available experimental △H^of0 and △H^of298 values for c-C3H2/c C3H2^＋, HCCCH/HCCCH^＋ are found to be in good accord with the CCSD（T）/CBS predictions after taking into account the experimental uncertainties.

On Sufficient Conditions for p-valently Close-to-convexity

Let A p(n)(p, n∈N=｛1,2,…｝) denote the class of functions of the form f(z)=z p+a p+n z p+n +… which are analytic in the unit disc E=｛z:｜z｜<1｝. By using the method of differential subordinati ons we give some sufficient conditions for a function f(z)∈A p(n) to be a certain subclass R p(n,k) of p-valently close-to-convexity funct ions.

Molecular Dynamics Insights into Electron-Catalyzed Dissociation Repair of Cyclobutane Pyrimidine Dimer

Excess electrons are not only an important source of radiation damage,but also participate in the repair process of radiation damage such as cyclobutane pyrimidine dimer(CPD).Using ab initio molecular dynamics(AIMD)simulations,we reproduce the single excess electron stepwise catalytic CPD dissociation process in detail with an emphasis on the energy levels and molecular structure details associated with excess electrons.On the basis of the AIMD simulations on the CPD aqueous solution with two vertically added excess electrons,we exclude the early-proposed[2+2]-like concerted synchronous dissociation mechanism,and analyze the difference between the symmetry of the actual reaction and the symmetry of the frontier molecular orbitals which deeply impact the mechanism.Importantly,we propose a new model of the stepwise electron-catalyzed dissociation mechanism that conforms to the reality.This work not only provides dynamics insights into the excess electron catalyzed dissociation mechanism,but also reveals different roles of two excess electrons in two bond-cleavage steps(promoting versus inhibiting).

Grammar Consciousness-Raising Tasks and Intermediate Learners＇ Achievement and Perceptions

While there is lots of empirical evidence showing that grammar consciousness raising tasks （GCRTs） have an edge over the traditional modes of grammar instruction, there is very little qualitative evidence reflecting learners＇ perceptions of externally imposed educational changes including GCRTs. To extrapolate the previous findings and fill in this gap, this study aims to： （I） test the alleged superiority of GCRTs in grammar instruction and （2） explore learners＇ perceptions of learning grammar through GCRTs. To this end, this study used a mixed-method design including a quantitative and a qualitative dimension. The former dimension aimed at testing the superiority of GCRTs on a random sample of intermediate learners from Simin language school in Karaj, Iran through the robust Solomon-four-group design and the latter dimension aimed at collecting and analyzing qualitative interview data on learners＇ perceptions of GCRTs. The quantitative results clearly showed that learners being taught through GCRTs significantly outperformed those instructed through the traditional mode of grammar instruction and the qualitative analysis of learners＇ perspectives showed that the participants had a positive perception of GCRTs and this positive perception was rooted in GCRTs＇ potential to： （1） facilitate the internalization of grammar and （2） involve learners in discovery learning. The findings have clear implications for syllabus designers and practitioners.

Ab Initio Molecular Dynamics Simulation of Liquid Water with Fragmentbased Quantum Mechanical Approach under Periodic Boundary Conditions

In this study,we investigated the structural and dynamical properties of liquid water by using ab initio molecular dynamics simulation under periodic boundary conditions based on the fragment-based quantum mechanical approach.This study was carried out using the second-order Møller-Plesset perturbation theory(MP2)with the aug-cc-pVDZ basis set,which has been validated to be sufficiently accurate for describing water interactions.Diverse properties of liquid water,including radial distribution functions,diffusion coefficient,dipole moment,triplet oxygen-oxygen-oxygen angles,and hydrogen-bond structures,were simulated.This ab initio description leads to these properties in good agreement with experimental observations.This computational approach is general and transferable,providing a comprehensive framework for ab initio predictions of properties of condensed-phase matters.

Dual Power Allocation Optimization Based on Stackelberg Game in Heterogeneous Network with Hybrid Energy Supplies

In heterogeneous network with hybrid energy supplies including green energy and on-grid energy, it is imperative to increase the utilization of green energy as well as to improve the utilities of users and networks. As the difference of hybrid energy source in stability and economy, thus, this paper focuses on the network with hybrid energy source, and design the utility of each user in the hybrid energy source system from the perspective of stability, economy and environment pollution. A dual power allocation algorithm based on Stackelberg game to maximize the utilities of users and networks is proposed. In addition, an iteration method is proposed which enables all players to reach the Stackelberg equilibrium(SE). Simulation results validate that players can reach the SE and the utilities of users and networks can be maximization, and the green energy can be efficiently used.

5-ASA in ulcerative colitis:Improving treatment compliance

5-aminosalicylic acid(5-ASA)compounds are a highly effective treatment for ulcerative colitis(UC).While UC patient compliance in clinical studies is over 90%, only 40%of patients in every day life take their prescribed therapy.Adherence to medication has been emphasized recently by a Cochrane meta-analysis that has suggested that future trials of 5-ASA in UC should look at patient compliance rather than drug efficacy. Better compliance can be obtained by reducing the number of tablets and times of administration.Given that the 5-ASA formulations have different delivery systems that split the active moiety in various regions of the intestine,it is particularly important that an adequate dose of the drug arrives at the inflamed part of the colon.5-ASA Multi matrix(MMx)is a novel,high strength(1.2 g),oral formulation designed for oncedaily dosing.It releases the active moiety throughout the colon.Different studies with this compound have shown that it is as effective as 5-ASA enema in the treatment of mild-to-moderate,left-sided UC,and is comparable to a pH-dependent,delayed release 5-ASA (Asacol ),even if given once daily.Recently,the effectiveness in the acute phase of UC has been confirmed also in maintenance.In conclusion,at present,5-ASA MMx seems theoretically the best agent for maintaining patient compliance,and consequently,treatment effectiveness.

Adherence-A concept analysis in the context of cardiac rehabilitation

Objective： To explore and identify the concept of adherence in the context of cardiac rehabilitation. This conceptanalysis will provide a framework for clinical decision-making and intervention to improve patients’ adherence tocardiac rehabilitation programme. Method： Walker and Avant’s framework was used to analysis the concept ofadherence. Results： Adherence is defined as patients collaboration with health care provider, active involvement in thetreatment regimen, and persistence in practice characterized by self-efficacy and relapse-prevention. Defining Attributesof adherence include collaboration relationship; self-efficacy promotion and relapse-prevention. Antecedents ofadherence include health care provider’s prescription, illness perceptions, social-economic and environmental factors.Patients adherence to cardiac rehabilitation programme can improve clinical outcomes. However, there is no standardinstrument to measure adherence. Conclusion： Based on the concept analysis, in order to improve patients’ adherence tocardiac rehabilitation, health care provider should invite patients active involvement in making rehabilitation plan andpromote patients’ self-efficacy and prevention relapse.

Molecular Simulation Studies on Basicity of Nitrogen-containing Compounds

The DFT-based （density fimctional theory） ab initio quantum mechanical methods have been applied to study the basicity of the nitrogen-containing compounds in petroleum. The results have indicated that there is a distinct relationship between the protonation energy of nitrogen-containing compounds and their basicity. The more negative the protonation energy, the stronger the basicity is. It has been also found that aliphatic amines are more basic than pyridines or aromatic amines, and all these compounds are more basic than pyrroles. The addition of the aromatic rings can influence the basicity of anilines, while the 5- and 6-membered heterocyclic compounds function differently. The solvent properties may affect the basicity of these nitrogen-containing compounds.