双联齿轮断裂分析

机床传动系统双联直齿轮投入运行不久即发生齿面断裂事故,造成较大经济损失.传动系统所用双联齿轮未达到设计使用寿命,属于早期断裂失效.对现场收集到的断裂齿轮残块进行化学成分分析和硬度测试,对齿廓工作面及断裂形成的断口用扫描电镜进行微观观察,对齿轮残块上出现的裂纹用光学金相显微镜观察其形貌和微观特征,依据检测实验数据和结果,...     

Local Nonautonomous Schrödinger Flows on Kähler Manifolds

In this paper, we prove that the nonautonomous Schrödinger flow from a compact Riemannian manifold into a Kähler manifold admits a local solution     

Self-consistent mean field approximation and application in three-flavor NJL model

In this study, we apply a self-consistent mean field approximation of the three-flavor Nambu–Jona-Lasinio(NJL) model and compare it with the two-flavor NJL model. The self-consistent mean field approximation introduces a new parameter, α, that cannot be fixed in advance by the mean field approach itself. Due to the lack of experimental data, the parameter, α, is undetermined. Hence, it is regarded as a free parameter and its influence on the chiral phase transition of strong interaction matter is studied based on this self-consistent mean field approximation. α affects numerous properties of the chiral phase transitions, such as the position of the phase transition point and the order of phase transition. Additionally, increasing α will decrease the number densities of different quarks and increase the chemical potential at which the number density of the strange quark is non-zero. Finally, we observed that α affects the equation of state(EOS) of the quark matter, and the sound velocity can be calculated to determine the stiffness of the EOS, which provides a good basis for studying the neutron star mass-radius relationship.     

Transverse Ward-Takahashi identities and full vertex functions in different representations of QED_3

We derive the transverse Ward-Takahashi identities(WTI) of N-dimensional quantum electrodynamics by means of the canonical quantization method and the path integration method, and subsequently attempt to prove that QED_3 is solvable based on the transverse and longitudinal WTI, indicating that the full vector and tensor vertices functions can be expressed in terms of the fermion propagators in QED_3. Further, we discuss the effect of different γ matrix representations on the full vertex function.     

Approach to High Open‐Circuit Voltage in Organic Solar Cells Utilizing a Structural Change of the Oxazolino‐C70 Derivative

Reactions of 2,5‐Bn₂C₇₀ (Bn=CH₂Ph) with hydroxide and ArCN (Ar=Ph, m‐ClPh) followed by quenching with I₂ and BnBr afforded dibenzylated and tetrabenzylated oxazolino[70]fullerenes, respectively. The latter has a novel structural configuration, in which the addends are positioned from the polar to the transequatorial region. A key structural feature of this compound is that the oxygen atom of the oxazoline ring is bound to the equatorial belt region of C₇₀, giving structural change in its reduced state. This enables stabilization of the reduced state, suppressing charge recombination dynamics in organic solar cells to give a high open‐circuit voltage (0.85, 0.93, and 1.11 V in devices using P3HT, PTB7, and DPP(TBFu)₂, respectively).