Chinese EFL Learners' Comprehension of English Idiom Variants:Effects of Variation Type and Proficiency Level

The creative use of English idioms has led to heterogeneous idiom variants that are particularly problematic for L2 learners. Drawing on a cognitive linguistic perspective of idiom learning, this paper categorizes English idiom variants into four major types, and reports on an empirical study that investigated the effects of variation type and proficiency level on Chinese EFL learners＇ comprehension of English idiom variants. Targeting non-English major college students of basic and intermediate English levels, the study confirmed the influence of proficiency level on learners＇ comprehension and evaluation of the difficulty of idiom variants. Structural change in idioms was found to be the easiest type and idioms modified in terms of literal imagery were the most difficult in comprehension. These findings suggest that the dominant ＂rote memorization＂ tends to limit learners＇ choices of comprehension strategies to literal translation and L1 transfer. The learning environment unsupportive of cultivating L2 learners＇ analytical ability is held accountable for the generally low success rates in comprehension of idiom variants.

Genetic Variation of Porcine Circovirus Type 2 Isolate 201105ZJ

[Objective] This study aimed to investigate the genetic variation of porcine circovirus type 2 （PCV2） in China. [Method] The strain was isolated from infected samples by cel passage and preliminarily identified by PCR and IFA. Ful-length genome of the isolated strain was obtained by specific amplification for homology and phylogenetic analysis. [Result] A PCV2 strain was successful y isolated and named 201105ZJ, which could proliferate in PK15 cel lines. Specific fragments could be amplified by specific PCR assay. According to results of IFA assay, specif-ic immunofluorescence was observed; the TCID50 was low （102.67）; the ful-length genome sequence of the isolated strain was 1 768 bp, sharing 94.1%-96.8% ho-mology with 13 reference strains; to be specific, the isolated strain exhibited the highest homology of 96.8% with AF055392PCV2a; the isolated strain 201105ZJ and reference strain AF055392 belonged to genotype PCV2a, exhibiting a distant genetic relationship with genotype PCV2c. [Conclusion] Characteristics of genetic variation of PCV2 isolate 201105ZJ provided theoretical basis for vaccine development, investi-gation of PCV2 pathogenesis, and prevention and control of porcine circovirus-as-sociated diseases （PCVAD） in East China.

Conservation laws for Birkhoffian systems of Herglotz type

Conservation laws for the Birkhoffian system and the constrained Birkhoffian system of Herglotz type are studied. We propose a new differential variational principle, called the Pfaff-Birkhoff-d＇Alembert principle of Herglotz type. Birkhoff＇s equations for both the Birkhoffian system and the constrained Birkhoffian system of Herglotz type are obtained. According to the relationship between the isochronal variation and the nonisochronal variation, the conditions of the invariance for the Pfaff-Birkhoff-d＇Alembert principle of Herglotz type are given. Then, the conserved quantities for the Birkhoffian system and the constrained Birkhoffian system of Herglotz type are deduced. Furthermore, the inverse theorems of the conservation theorems are also established.

A new type of adiabatic invariants for disturbed non-conservative nonholonomic system

According to the Herglotz variational principle and differential variational principle of Herglotz type, we study the adiabatic invariants for a non-conservative nonholonomic system. Firstly, the differential equations of motion of the non-conservative nonholonomic system based upon the generalized variational principle of Herglotz type are given, and the exact invariant for the non-conservative nonholonomic system is introduced. Secondly, a new type of adiabatic invariant for the system under the action of a small perturbation is obtained. Thirdly, the inverse theorem of the adiabatic invariant is given. Finally, an example is given.

The energy levels of a two-electron two-dimensional parabolic quantum dot

This paper studies the two-electron total energy and the energy of the electron-electron interaction by using a variational method of Pekar type on the condition of electric-LO-phonon strong coupling in a parabolic quantum dot. It considers the following three cases： 1） two electrons are in the ground state; 2） one electron is in the ground state, the other is in the first-excited state; 3） two electrons are in the first-excited state. The relations of the two-electron total energy and the energy of the electron-electron interaction on the Coulomb binding parameter, the electron-LO-phonon coupling constant and the confinement length of the quantum dot are derived in the three cases.

Influence of an anisotropic parabolic potential on the quantum dot qubit

To study the influence of an anisotropic parabolic potential （APP） on the properties of a quantum dot （QD） qubit, we obtain the eigenenergies and eigenfunctions of the ground and first excited state of an electron, which is strongly coupled to the bulk longitudinal optical （LO） phonons, in a QD under the influence of an APP by the celebrated Lee-Low-Pines （LLP） unitary transformation and the Pekar type variational （PTV） methods. Then, this kind of two-level quantum system can be excogitated to constitute a single qubit. When the electron locates at the superposition state of its related eigenfunctions, we get the time evolution of the electron＇s probability density. Finally, the influence of an APP on the QD qubit is investigated. The numerical calculations indicate that the probability density will oscillate periodically and it is a decreasing function of the effective confinement lengths of the APP in different directions. Whereas its oscillatory period is an increasing one and will diminish with enhancing the electron-phonon （EP） coupling strength.