Pairing effects on the fragment mass distribution of Th,U,Pu,and Cm isotopes

In this article,a comprehensive study of the fission process of Th,U,Pu,and Cm isotopes using a Yukawa-folded meanfield plus standard pairing model is presented.The study focused on analyzing the effects of the pairing interaction on the fragment mass distribution and its dependence on nuclear elongation.The significant role of pairing interactions in the fragment mass distributions of^(230)Th,^(234)U,^(240)Pu,and^(246)Cm was demonstrated.Numerical analysis revealed that increasing the pairing interaction strength decreased the asymmetric fragment mass distribution and increased the symmetric distribution.Furthermore,the odd-even mass differences at symmetric and asymmetric fission points were examined,highlighting their sensitivity to changes in the pairing interaction strength.Systematic analysis of the Th,U,Pu,and Cm isotope fragment mass distributions demonstrated the effectiveness of the model in reproducing the experimental data.In addition,the effects of the zero-point energy and half-width parameter on the fragment mass distribution for^(240)Pu were explored.Thus,this study provides valuable insights into the fission process by emphasizing the importance of pairing interactions and their relationship with nuclear elongation.

Interaction of a parabolic-shaped pulse pair in a passively mode-locked Yb-doped fiber laser

We numerically investigate the formation and interaction of a parabolic-shaped pulse pair in a passively mode-locked Yb-doped fiber laser. Based on a lumped model, the parabolic-shaped pulse pair is obtained by controlling the intercavity average dispersion and gain saturation energy, Moreover, pulse repulsive and attractive motion are also achieved with different pulse separations. Simulation results show that the phase shift plays an important role in pulse interaction, and the interaction is determined by the inter-cavity average dispersion and gain saturation energy, i.e., the strength of the interaction is proportional to the gain saturation energy, a stronger gain saturation energy will result in a higher interaction intensity. On the contrary, the increase of the inter-cavity dispersion will counterbalance some interaction force. The results also show that the interaction of a parabolic-shaped pulse pair has a larger interaction distance compared to conventional solitons.

The Role of Learner-learner Interaction In Language Learning

This paper is committed to exploring the importance of learner learner interaction for language learning. It starts with a discussion of the roles that learner learner interaction plays in language learning from two points of view pedagogic and psycholinguistic, which is followed by a brief guideline for organizing group work in class.

Highly efficient catalyst for 1,1,2-trichloroethane dehydrochlorination via BN_(3) frustrated Lewis acid-base pairs

In this study,a novel non-metallic carbon-based catalyst co-doped with boron and nitrogen(B,N)was successfully synthesized.By precisely controlling the carbonization temperature of a binary mixed ionic liquid,we selectively modified the doping site structure,ultimately constructing a B,N co-doped frustrated Lewis acid-base pair catalyst.This catalyst exhibited remarkable catalytic activity,selectivity,and stability in the dehydrochlorination reaction of 1,1,2-trichloroethane(TCE).Detailed characterization and theoretical calculations revealed that the primary active center of this catalyst was the BN_(3)configuration.Compared to conventional graphitic N structures,the BN_(3)structure had a higher p-band center,ensuring superior adsorption and activation capabilities for TCE during the reaction.Within the BN_(3)site,three negatively charged nitrogen atoms acted as Lewis bases,while positively charged boron atoms acted as Lewis acids.This synergistic interaction facilitated the specific dissociation of chlorine and hydrogen atoms from TCE,significantly enhancing the 1,1-dichloroethene selectivity.Through this research,we not only explored the active site structure and catalytic mechanism of B,N co-doped catalysts in depth but also provided an efficient,selective,and stable catalyst for the dehydrochlorination of TCE,contributing significantly to the development of non-metallic catalysts.

Efficient nitrite-to-ammonia electroreduction over Zr-Ni frustrated Lewis acid-base pairs

Electrochemical NO_(2)~--to-NH_(3) conversion(NO_(2)RR) offers a green route to NH_(3) electrosynthesis, while developing efficient NO_(2)RR catalysis systems at high current densities remains a grand challenge. Herein, we report an efficient Zr-NiO catalyst with atomically dispersed Zr-dopants incorporated in NiO lattice, delivering the exceptional NO_(2)RR performance with industriallevel current density(>0.2 A cm^(-2)). In situ spectroscopic measurements and theoretical simulations reveal the construction of ZrNi frustrated Lewis acid-base pairs(FLPs) on Zr-Ni O, which can substantially increase the number of absorbed nitrite(NO_(2)~-),promote the activation and protonation of NO_(2)~- and concurrently hamper the H coverage, boosting the activity and selectivity of Zr-NiO towards the NO_(2)RR. Remarkably, Zr-NiO exhibits the exceptional performance in a flow cell with high Faradaic efficiency for NH_(3) of 94.0% and NH_(3)yield rate of 1,394.1 μmol h^(-1)cm^(-2) at an industrial-level current density of 228.2 m A cm^(-2),placing it among the best NO_(2)RR electrocatalysts for NH_(3) production.

Numerical Study on Interaction Between Two Bubbles Rising Side by Side in CMC Solution

A numerical simulation was performed to investigate the interaction of two bubbles rising side by side in shear-thinning fluid using volume of fluid （VOF） method coupled with continuous surface force （CSF） method. By considering rheological characteristics of fluid, this approach was able to accurately capture the deformation of bubble interface, and validated by comparing with the experimental results. The rising of bubble pairs with different configurations, including horizontal alignment and oblique alignment, was simulated by the method. The influences of the bubble initial distance and the bubble alignment were studied by analyzing the bubble deformation, rising paths and flow fields surrounding bubbles. The results indicate that within certam mltlal bubble spacing of S = 3.3 （S＊ = SI/D, SI initial distance between bubbles, and D bubble diameter）, the dynamic interaction between two bub- bles aligned horizontally shows repulsive effect that decreases with the increase of initial bubble spacing, but weakens to certain degree by the shear-thinning properties of fluid. However, the interaction between two bubbles aligned obliquely presents a repulsive effect for the small angle involved but an attractive impact for the large one, which is vet strengthened by the rheological characteristics of fluid.

Single Photon Scattering in a Pair of Waveguides Coupled by a Whispering-Gallery Resonator Interacting with a Semiconductor Quantum Dot

The single photon scattering properties in a pair of waveguides coupled by a whispering-gallery resonator in- teracting with a semiconductor quantum dot are investigated theoretically. The two waveguides support four possible ports for an incident single photon. The quantum dot is considered a V-type system. The incident direction-dependent single photon scattering properties are studied and equal-output probability from the four ports for a single photon incident is discussed. The influences of backscattering between the two modes of the whispering-gallery resonator for incident direction-dependent single photon scattering properties are also pre- sented.

Non-covalent Bonded 3D Supramolecular Architectures Based on Acid-base Adducts

Two novel acid-base adducts,[H2L1^2＋]（Hpbda）2（1,L1 = 1,4-di（lH-imidazol-4-yl）benzene,H2pbda = 1,4-benzenedicarboxylic acid） and[H2L2^2＋]（NO3）2（2,L2 = l,4-di（l-carboxymethyl-imidazol-4-yl）benzene）,have been prepared and characterized by single-crystal X-ray diffraction,IR spectroscopy and elemental analysis.Compound 1 crystallizes in monoclinic,space group P21/n with a = 5.3525（11）,b = 9.1471（19）,c = 19.314（4） ？,β = 92.342（3）°,V= 944.8（3） A°3,Z = 2,C16H16N6O（10）,Mr = 452.35,Dc = 1.590 g/cm^3,μ = 0.135 mm^-1,S = 1.058,F（000） = 468,the final R = 0.0661 and wR = 0.1887 for 2298 observed reflections（I〉 2σ（I））.Compound 2 crystallizes in monoclinic,space group P21/c with a = 9.6923（10）,b = 17.2950（17）,c = 7.1880（7） ？,β =94.801（2）°,V= 1200.7（2）A°3,Z = 2,C（28）H（22）N4O8,Mr = 542.50,Dc = 1.501 g/cm^3,μ = 0.112 mm^-1,S= 1.060,F（000） = 564,the final R = 0.0394 and wR = 0.1017 for 2768 observed reflections（I 〉2σ（I））.In the title compounds,both of L1 and L2 ligands act as weak base to accept protons to exhibit diprotonated H2L1^2＋ and H2L2^2＋ form,which can effectively employ as hydrogen bonding donors to combine anion moieties to form binary adducts respectively.In the crystal packing diagram of two polymers,there exist extensive noncovalent interactions including charge-transfer interactions,C（N）-H…π and N-H…O,C-H…O,O-H…O hydrogen bonding interactions between co-crystal moieties which consolidate the structures of supramolecular polymers,thus generating three-dimensional（3D） frameworks.

A critical assessment of the roles of water molecules and solvated ions in acid-base-catalyzed reactions at solid-water interfaces

Solid-aqueous interfaces and phenomena occurring at those interfaces are ubiquitously found in a plethora of chemical systems.When it comes to heterogeneous catalysis,however,our understanding of chemical transformations at solid-aqueous interfaces is relatively limited and primitive.This review phenomenologically describes a selection of water-engendered effects on the catalytic behavior for several prototypical acid-base-catalyzed reactions over solid catalysts,and critically assesses the general and special roles of water molecules,structural moieties derived from water,and ionic species that are dissolved in it,with an aim to extract novel concepts and principles that underpin heterogeneous acid-base catalysis in the aqueous phase.For alcohol dehydration catalyzed by solid Bronsted acids,rate inhibition by water is most typically related to the decrease in the acid strength and/or the preferential solvation of adsorbed species over the transition state as water molecules progressively solvate the acid site and form extended networks wherein protons are mobilized.Water also inhibits dehydration kinetics over most Lewis acid-base catalysts by competitive adsorption,but a few scattered reports reveal substantial rate enhancements due to the conversion of Lewis acid sites to Brønsted acid sites with higher catalytic activities upon the introduction of water.For aldol condensation on catalysts exposing Lewis acid-base pairs,the addition of water is generally observed to enhance the rate when C–C coupling is rate-limiting,but may result in rate inhibition by site-blocking when the initial unimolecular deprotonation is rate-limiting.Water can also promote aldol condensation on Brønsted acidic catalysts by facilitating inter-site communication between acid sites through hydrogen-bonding interactions.For metallozeolite-catalyzed sugar isomerization in aqueous media,the nucleation and networking of intrapore waters regulated by hydrophilic entities causes characteristic enthalpy-entropy tradeoffs as these water moieties interact with kinetically relevant hydride transfer transition states.The discussed examples collectively highlight the utmost importance of hydrogen-bonding interactions and ionization of covalently bonded surface moieties as the main factors underlying the uniqueness of water-mediated interfacial acid-base chemistries and the associated solvation effects in the aqueous phase or in the presence of water.A perspective is also provided for future research in this vibrant field.

Interaction Energies of Tetraalkylphosphonium Cation- and Amino Acid Anion- Based Ionic Liquids

Ab initio calculations were performed using the Gaussian 03 software package to obtain the optimized structure, interaction energy and infrared spectrum of ionic liquids （ILs） containing a tetraalkylphosphonium cation and an amino acid anion. In order to investigate the effect of the presence of nitrogen in the cation, the tetraalkylphosphonium cation was replaced by a tetraalkylammonium cation, while amino acids were retained as anions in the ionic liquid. The amino acids studied here included glycine, alanine, serine, lysine, and glutamine. Optimized structures of several ILs in the gas phase were determined at the levels of Hartree-Fock （HF/6-3＋G（d）） and 1density functional theory （B3LYP/6-3 1＋＋G（d,p））. At high-level estimations, MP2/6-31＋G（d） and MP2/6-31＋＋G（d,p）, the interaction energies between the cations and anions of the ILs were determined. In order to investigate the effect of alkyl-chain length on interaction energy, the alkyl groups were varied from methyl to ethyl and propyl in the tetraalkylphosphonium functional groups. This procedure revealed that there is a considerably stronger interaction between the alkylphosphonium cations and amino acids than between alkylammonium cations and amino acids. Vibrational spectroscopy of ILs shows that a significant -OH vibration peak occurs at 4124 cmt in serine-containing ILs, and a prominent C=O vending peak occurs at 1626 cm^-1 in amino acids.

Coulomb Interaction between Electrons and a New Concept of Atom

It is shown that the approximation of a strong Coulomb interaction between electrons results in a new model of the atom with a spatial quantization of electrons accompanied by their quantization in energy. This model implies that electrons rotate in circular orbits centered outside the atomic nucleus and only orbit axes pass through it. The Coulomb interaction between electrons leads to a spherically symmetric distribution of their orbits on the surfaces of equipotential spheres of a spherically symmetric electrostatic field of the nucleus. The distribution is similar to “inscribing” electron orbits into faces of regular nucleus-centered polyhedra so each polyhedron corresponds to a certain electron state (s, p, d, f), and a certain set of polyhedra corresponds to a certain period of the Mendeleev Table. It is shown that a spherically symmetric distribution of electron orbits gives rise to the formation of electron pairs in which electron orbits with a common axis are located symmetrically with respect to the nucleus and the orbital magnetic moments of the electrons are oppositely directed. The physical meaning of the electron spin concept becomes clear. The spin turns out to be related to the orbital magnetic moment of an electron and reflects the fact that two electrons of a pair rotate in opposite directions relative to their common axis. So the spin is one of characteristics of the electron state in the atom associated with electron rotation in the orbit centered outside the nucleus. The atomic model gives an insight into the periodicity of changes in the atomic properties with increasing nuclear charge and the reasons for an electron double energy quantization associated with different states and periods. The model shows that the atomic structure and properties can be explained by using concepts of classical mechanics and classical electrodynamics which regard the electron as a particle.

不同结对编程策略对小学生学习效果影响的比较研究

结对编程是一种以协作方式学习编程的教学策略,该研究将结对编程与单独编程相结合,构成混合结对编程策略,采用准实验研究法,从编程总评成绩、结对融洽度、结对互动话语等方面,探究混合结对编程和常规结对编程两种策略对小学生学习编程效果影响的差异。实验结果表明,混合结对编程策略能够增进结对伙伴之间的融洽度,促进学生之间的积极互动,提高小学生的编程能力。教师应正确认识结对编程与单独编程的价值,通过组合应用,提高编程教学实效。

激发态DNA碱基对分子间相互作用的理论研究

[目的]利用本课题组发展的定量分析方法研究激发态DNA碱基对分子间相互作用的本质,以及不同类型的电子跃迁对DNA碱基对分子间相互作用的影响.[方法]采用广义Kohn-Sham能量分解分析方法(generalized Kohn-Sham based energy decomposition analysis,GKS-EDA),对两种Waston-Crick构型和两种stacked构型的DNA碱基对分子间相互作用本质进行理论研究.[结果]对于Waston-Crick构型的碱基对,n→π^(*)跃迁削弱了轨道极化作用但加强了电子相关作用,激发态分子间相互作用由电子相关作用主导,而π→π^(*)跃迁对分子间氢键影响较小;对于stacked构型的碱基对,π→π^(*)跃迁削弱了静电相互作用但增强了电子相关作用.[结论]Waston-Crick构型碱基对分子间相互作用本质受电子激发跃迁影响较大,而电子激发跃迁基本不改变stacked构型碱基对分子间相互作用本质.

基于“阴阳交感”及临床药理探讨“黄连-肉桂”对失眠的治疗

药物配伍是中医的魂之所在,用药如用兵,善用方者,必善药之配伍,执简驭繁。失眠皆因阳盛阴衰,阴阳失交所致,而临床上心肾不交型失眠尤为多见。黄连,味苦性寒,有泻火之功,当属阴药;肉桂,味辛甘、性大热,有补火助阳、引火归元之功,当属阳药。“黄连-肉桂”配伍,交通心肾阴阳二气,可治阴阳失调、心肾不交所致失眠之症。“黄连-肉桂”联用效果更显著,一种可能是由于两药联用后会使有效成分的溶出率更高,还有一种可能是会增多或抑制相关蛋白的表达。通过探讨“黄连-肉桂”所体现的阴阳交感的中医思想,不仅可以为治疗阴阳失调提供新的思路,也可以通过现代药理研究预测出治疗失眠的新机制,并通过实验进行药效验证,为中西医结合治疗失眠打开新思路。

单线态裂分中间态的理论研究进展

单线态裂分是指有机材料在光激发后,从一个单重态激子转变为两个三重态激子的光物理过程。该过程有望提高光电转换效率,因而受到了广泛的关注。研究发现单线态裂分中存在一个关键的中间态,而如何构建中间态的波函数则是重要的挑战。本文着重介绍了双激发态波函数构建的两类理论模型,而后讨论了振动、轨道和自旋相互作用对中间态形成和解离的影响。最后总结了进一步的理论研究将面临的挑战。

Towards Understanding Energy Levels of Two Identical Nucleons with Delta Interaction

In this paper we study a given system of two identical nucleons in the presence of an attractiveδinteraction.We derive the formulas for energies of identical nucleons with the configuration|j_1j_2J>explicitly,and explain all empirical rules of the energy level ordering with spin J and parity,deep understandings of which have been desirable for a few decades.We also proved analytically that the energy interval between the lowest level and the second lowest level is larger than the sum of intervals of all other successive levels,thus present a sound explanation of the large energy gap between the ground state and the first excited state of such system.

融合成对损失函数与分级图卷积网络的协同排名模型

协同排名方法是一类直接优化推荐项目序列的推荐方法,但在显式评分场景中,现有的协同排名算法对用户和项目间的交互信息利用不足,使用的交互函数对用户和项目间的非线性交互关系建模不充分。针对此问题,提出一种融合成对损失函数与分级图卷积网络的协同排名模型。首先根据评分数据构造用户和项目的分级异质交互二部图以及项目间的成对比较集合;之后利用分级图卷积网络挖掘用户和项目间的异质交互关系,并设计相应的自连接操作;接着利用神经网络融合辅助信息以构造两者的嵌入表示,结合神经网络与内积构造用户项目间的交互函数以建模非线性关系;最后基于成对比较数据优化模型,提升模型预测排名质量。在多个公开数据集上与同类方法的对比实验结果表明,所提算法预测排名质量较优。

Nilsson平均场加对力模型的近似角动量投影的可行性分析

为了讨论Nilsson平均场加对力模型的近似角动量投影方法的可行性,以ds壳为例,分析了严格角动量投影和近似角动量投影结果中2_(1)^(+),4_(1)^(+)和0_(2)^(+)能级与波函数的关系.结果表明,在对力强度参数不太小时,可以用近似角动量投影方案来恢复Nilsson平均场加对力模型的角动量.

New loop pairing criterion based on interaction and integrity considerations

Loop pairing is one of the major concerns when designing decentralized control systems for multivariable processes.Most existing pairing tools,such as the relative gain array(RGA) method,have shortcomings both in measuring interaction and in integrity issues.To evaluate the overall interaction among loops,we propose a statistics-based criterion via enumerating all possible combinations of loop statuses.Furthermore,we quantify the traditional concept of integrity to represent the extent of integrity of a decentralized control system.Thus,we propose that a pairing decision should be made by taking both factors into consideration.Two examples are provided to illustrate the effectiveness of the proposed criterion.

Time-dependent Calculations for Two-proton Decay Width with Schematic Density-dependent Contact Pairing Interaction

We calculate the two-proton decay width of the6 Be nucleus employing the schematic densitydependent contact potential for the proton-proton pairing interaction. The decay width is calculated with a time-dependent method, in which the two-proton emission is described as a time-evolution of a threebody meta-stable state. Model-dependence of the two-proton decay width has been shown by comparing the results obtained with the two different pairing models, schematic density-dependent contact and Minnesota interactions, which have zero and finite ranges, respectively.