Factors Affecting Polymer Translocation Through a Nanopore in a Membrane

The variation of the translocation time with respect to the solvent quality was also studied. It showed that there is a transition, as the solvent quality improves from \poor to \good: when ABc, τ increases with increasing AB. When the chain length was changed, it was found that when the absorbed energy u0 was greater than uc, τ was proportional to N1:602; for u0相似文献   

原子吸收光谱法测量质量控制研究

以原子吸收光谱法对锌合金标准物质中的铜元素定值为例,运用田口方差分析方法对定值数据进行分析处理,实现元素定值过程的质量控制。从实验设计方案的角度确定实验过程的不确定度,对溶解、等份稀释、仪器校准三部分的实验步骤分别进行数据处理,计算各部分方差波动对总实验数据波动的贡献率,从而确定最主要的不确定度来源。     

Probing R-parity Violating Interactions via pp^-→eμ＋X Channel on Tevatron

We investigate the lepton flavor violation processes pp→eμX induced by R-parity violating interactions at the Tevatron hadron collider. The theoretical calculation and Monte Carlo simulation demonstrate that with a set of suitable cuts on experimental observables, one might be capable to reduce the standard model physical background to a controllable level so that the signals of R-parity violating interactions could be detected distinctively. Furthermore, clear sneutrino information can be abstracted from the purified event sample where other SUSY scalar quark ``pollution' is heavily suppressed. We conclude that with a reasonable assumption of 10 fb^-1 integrated luminosity, the experiments at the Tevatron machine would have potential to discover sneutrino in the region of m_{\tilde{ν}}≤400 GeV via lepton flavor violation eμ production channels, or extend the mass scale constraint up to m_{\tilde{ν}}≥ 550 GeV at 95% CL.     

The dynamical feature of transition of a Hamiltonian system to a dissipative system

The mechanism of generation and annihilation of attractors during transition from a Hamiltonian system to a dissipative system is studied numerically using the dissipative standard map. The transient process related to the formation of attracting basins of periodic attractors is studied by discussing the evolution of the KAM tori of the standard map. The result shows that as damping increases, attractors are mainly generated from elliptic orbits of the Hamiltonian system and annihilated by colliding with unstable periodic orbits originating from the corresponding hyperbolic orbits of the Hamiltonian system. The transient process also exhibits the general feature of bifurcation.     

从环境教育视角解析新化学课程标准

本文从环境教育角度对教育部制定的《全日制义务教育化学课程标准 (实验稿)》的前言、课程目标、内容标准和实施建议 4部分做了分析和讨论。     

Special Elements of the Lattice of Overcommutative Varieties of Semigroups

The distributive, codistributive, standard, costandard, and neutral elements of the lattice of overcommutative varieties of semigroups are completely described.     

高等数学教学中落实素质教育之浅见

本文主要讨论了数学素质教育的重要性及如何具体在高等数学教学中培养学生的数学素质     

振动轮式微机械陀螺频率配置和气压选择

推导了振动轮式微机械陀螺的输出信号与输入角速度的幅频、相频关系,讨论了在不同的频率配置和品质因数下陀螺的灵敏度、带宽和零位稳定性。陀螺振动频率应设计在2kHz左右,检测轴自然频率比驱动轴高一个陀螺频带宽度。根据实测陀螺振动品质因数与气压的关系曲线,振动轮式微机械陀螺合适的工作气压是100Pa-1000Pa。     

Thermodynamics of Silicon Nitride. Standard molar enthalpy of formation of amorphous Si3N4 at 298.15 K

The standard molar enthalpy of formation Δ_f H _m ⁰=–760±12 kJ for amorphous silicon nitride a-Si₃N₄ has been determined from fluorine combustion calorimetry measurements of the massic energy of the reaction: a-Si₃N₄(s)+6F₂(g)=3SiF₄(g)+2N₂(g). This value combined with Δ_f H _m ⁰= –828.9±3.4 kJ for a-Si₃N₄ indicates that determined for the first time molar enthalpy change for the transition from amorphous to α-crystalline form Δ_trs H _m ⁰=69±13 kJ is very evident, in spite of its large uncertainty range resulting from impurity corrections. This revised version was published online in July 2006 with corrections to the Cover Date.     

氩气中一氧化碳、二氧化碳、甲烷、乙烷混合气体标准样品的研制

介绍气体报警仪标定和检测使用的氩气中一氧化碳、二氧化碳、甲烷、乙烷气体标准样品的制备,以气相色谱法对其均匀性和稳定性进行考核,对定值结果的不确定度进行了评定。标准气体定值范围:一氧化碳为500～1000μmol/mol,不确定度2%;二氧化碳为1000～5000μmol/mol,不确定度2%;甲烷为300～500μmol/mol,不确定度3%;乙烷为300～500μmol/mol,不确定度3%。