聚焦辐照条件对脉冲CO_2激光诱导液体气穴通道效应的影响

利用高速摄像技术检测脉冲CO2激光诱导液体气穴通道形成、发展和坍塌的动态过程,考察不同聚焦辐照条件对气穴效应的影响。实验获得了气穴通道脉动过程的序列图像,得到了表征气穴通道特性的参数(如最大穿透深度等)。实验结果表明,不同聚焦条件对气穴通道的动力学过程有显著影响。正离焦及焦点位置条件下,气穴通道在最大纵深时,整体形态类似于漏斗状,而负离焦条件下,则呈U形。研究结果对激光医疗、激光水下加工、能源等领域的研究具有一定的参考价值。     

Determination of ablation threshold of dental hard tissues irradiated with Er:YAG and Er,Cr:YSGG lasers

We evaluate the ablation thresholds of Er:YAG and Er,Cr:YSGG laser for enamel and dentin.A total of 140 dental slices is evenly divided into two groups:the dentin group and the enamel group.Dental tissues are irradiated with either an Er:YAG laser or an Er,Cr:YSGG laser with pulse widths in the order of 100 μs.The laser fluence is increased gradually until the ablation crater is formed.The laser ablation threshold is calculated using probit analysis.The ablation thresholds of the Er:YAG laser for dentin and enamel range from 2.88 to 3.36 J/cm2 and from 2.94 to 3.8 J/cm2,respectively,and the ablation thresholds of the Er,Cr:YSGG laser for dentin and enamel range from 2.92 to 4.2 J/cm2 and from 4.93 to 5.66 J/cm2,respectively.     

Computational and Theoretical Chemistry in Structure-Reactivity Studies of Organophosphorus Compounds

Computational multivariation analysis, molecular orbital calculation as well as molecular mechanics study were used for the qualitative and quantitative evaluation of the relationship between chemical structure and reactivity of organophosphorus compounds.     

Norms of the composition of the maximal and projection operators

In this paper, we develop different norm estimates for the compositions of the maximal and projection operators, applied to the solutions of a nonlinear elliptic partial differential equation. As applications, we also obtain some estimates related to the Jacobian and exponents of mappings.     

Study on the formation and role of copper chloride hydroxide in the oxidative carbonylation of methanol to dimethyl carbonate

The synthesis of dimethyl carbonate by oxidative carbonylation of methanol over CuCl/SiO₂-TiO₂ catalysts has been investigated in a slurry reaction system. The γ-Cu₂(OH)₃Cl crystals were detected by X-ray diffraction on the catalysts after reaction. It was revealed that γ-Cu₂(OH)₃Cl was formed by CuCl reacting with O₂ and by-product water. The catalytic tests showed that γ-Cu₂(OH)₃Cl was largely inactive for this reaction, may be attributed to its high stability that resisted the Cu⁺/Cu²⁺ redox cycle.     

动作电位编码光学二次谐波快速检测神经纤维膜电位动力学

神经纤维膜电位动力学特性与神经信息的传导和编码密切关联。目前,传统电生理测量方法无法同时对膜上多个部位的动作电位进行快速检测。利用非线性光学二次谐波方法,通过数学建模,研究了髓鞘神经纤维动作电位编码的二次谐波信号特征及其检测灵敏性,并将其用于分析由压力引起的神经纤维形态改变,包括轴突直径和髓鞘厚度的改变,实现神经传导信息变化的快速检测。发现神经纤维膜电位的变化可以通过光学二次谐波信号的特征来表征。当神经纤维严重脱鞘时,其上的动作电位会产生明显的传输阻滞。结果表明光学二次谐波技术有望成为神经纤维损伤状态快速检测的一种有力手段。     

Bubbling Solutions for Relativistic Abelian Chern-Simons Model on a Torus

We prove the existence of bubbling solutions for the following Chern-Simons-Higgs equation:

Infinitely many positive solutions for the nonlinear Schrödinger equations in {\mathbb{R}^N}

We consider the following nonlinear problem in ${\mathbb {R}^N}$ $$- \Delta u +V(|y|)u = u^{p},\quad u > 0 \quad {\rm in}\, \mathbb {R}^N, \quad u \in H^1(\mathbb {R}^N), \quad \quad \quad (0.1)$$ where V(r) is a positive function, ${1< p < {\frac{N+2}{N-2}}}$ . We show that if V(r) has the following expansion: $$V(r) = V_0+\frac a {r^m} +O \left(\frac1{r^{m+\theta}}\right),\quad {\rm as} \, r\to +\infty,$$ where a > 0, m > 1, θ > 0, and V ₀ > 0 are some constants, then (0.1) has infinitely many non-radial positive solutions, whose energy can be made arbitrarily large.     

解二阶抛物型方程组的再生核函数法

建立了二阶抛物型方程组的一种新数值方法-再生核函数法.利用再生核函数,直接给出了每个离散时间层上近似解的显式表达式,由显式表达式可实现完全并行计算;用能量估计法证明了格式的稳定性及二阶收敛性;给出了一些数值结果.     

朋原子结构与原子辐射理论看玻尔新思维的特征

玻尔提出原子理论过程中的创新思维具有显著的开放性、批判性、辩证性和非逻辑性特征，对当前的科技创新和科学教育有重要的启迪，促使我们对摆脱旧有观念束缚、充分利用直觉思维、恰当处理精确与的关系等问题进行了深入的思考。