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上颌中切牙倒置阻生临床上较少见,矫治方法和理念也不同于其他阻生牙的导萌。缺失上颌中切牙严重影响美观及功能,所以临床上应及早发现并治疗,以利于患者自信心的建立。本文主要介绍了上颌中切牙倒置阻生的原因、治疗方法及保持。     

浅谈人之“八纲脉”

人之脉象大体可从脉位、脉率、脉力、脉畅四个角度,分为浮和沉、迟和数、实和虚、滑和涩八种典型病脉,统称“八纲脉”。八纲脉为辨脉之提纲,可辨别病之表里、寒热、实虚、在气在血,为识脉辨证之捷径。证之临床,该方法提纲挈领,不仅有助于初学者去芜存菁,掌握脉学之要,而且直指临证,指导辨证论治。     

基于“清”“消”“补”探析骨痨汤治疗骨结核的组方特点

目的:该院使用骨痨汤作医治骨结核多年,临床观察证明治疗骨结核有效,故探析骨痨汤的组方特点,以更明确地为骨痨汤的临床运用奠定理论基础。方法:在中医理论的指导下,根据君臣佐使的组方原则对方中10味药物药性、功效进行分析。结果:骨痨汤组方合理,选药精确,融合了中医"清""消""补"三法,突出了清热解毒、活血化瘀的功效,益气抗痨贯彻始终。结论:骨痨汤体现了治本为主、标本兼治的中医治疗原则,效果显著,值得临床的进一步推广应用。     

中医药对新型冠状病毒肺炎的认识与防治

目的探讨中医药对新型冠状病毒肺炎(简称新冠肺炎)的认识与防治措施。方法从中医学角度分析新冠肺炎的归属、病因、病机,以及防治原则、临床组方方法。结果新冠肺炎属中医"疫"病范畴,病位在肺,病因病机为"湿、毒、热",目前临床的防治组方多以"扶正固表"为基础,在疾病不同阶段辨证论治,综合制订治疗方案。结论中医药防治新冠肺炎具有理论优势、经验优势和药物优势,不足之处是中药传统剂型起效慢和中药注射剂存在安全性问题。中西医结合治疗、辨证论治思想、因地制宜、隔离和个人防护等因素对该病的防治有着重要意义。     

基于Cog Tool的数字界面交互行为认知模型仿真研究

目的确定人在视觉信息搜索中的通用认知模式,归纳符合用户认知模式的基本设计准则。方法在用户需求一致性的前提下,通过Cog Tool可视化仿真模型将用户交互过程中的每一步骤进行拆解分析,找出用户在面对不同界面引导作用下的内在认知规律,并探讨界面布局的不同对用户搜索用时的影响,同时结合眼动实验,对比用户在实际操作过程中与模拟操作情况下的认知差异。结果通过Cog Tool的仿真分析与眼动实验相结合的实验数值对比,将用户在交互过程中的内在认知规律提取出来。结论本研究提出的面向界面布局的设计准则,可帮助设计师提高信息认知效率。     

Giant exciton-enhanced shift currents and direct current conduction with subbandgap photo excitations produced by many-electron interactions

Shift current is a direct current generated from nonlinear light–matter interaction in a noncentrosymmetric crystal and is considered a promising candidate for next-generation photovoltaic devices. The mechanism for shift currents in real materials is, however, still not well understood, especially if electron–hole interactions are included. Here, we employ a first-principles interacting Green’s-function approach on the Keldysh contour with real-time propagation to study photocurrents generated by nonlinear optical processes under continuous wave illumination in real materials. We demonstrate a strong direct current shift current at subbandgap excitation frequencies in monolayer GeS due to strongly bound excitons, as well as a giant excitonic enhancement in the shift current coefficients at above bandgap photon frequencies. Our results suggest that atomically thin two-dimensional materials may be promising building blocks for next-generation shift current devices.

When continuous wave light is shone on a noncentrosymmetric crystal, a direct current (DC) can arise due to a second-order optical response of the crystal. The origin of this current is interpreted to be related to the “shift” (1–4) of the intracell coordinates of the excited electron. This so-called shift current is proposed as an alternative to the photocurrent generated by traditional semiconductor p–n junctions (i.e., a junction between hole-doped [p-type] and electron-doped [n-type] semiconductors) for photovoltaic applications (5, 6). Unlike conventional photovoltaic devices, shift current is a bulk phenomenon, which does not require a p–n junction to separate the optically generated electron–hole pair for a DC. Moreover, recent studies reveal that the photocarriers in shift current can have long travel distances, which is distinct from the usual drift transport mechanism in traditional solar cells (7, 8) and makes shift current a promising candidate for efficient energy conversion.Despite many investigations over the past decade, a basic understanding of shift currents is far from complete. Most theoretical studies to date rely on the assumption of having noninteracting particles (3–6, 9–11). Given that it is well known that light-induced electron–hole pairs can form bound or resonant excitons (correlated electron–hole states), which dominate and qualitatively change the absorption features of semiconductors, electron–hole interactions or excitons are expected to play a large role in shift currents, especially for reduced dimensional systems. However, it is not straight forward to generalize existing ab initio methods [such as the ab initio GW plus Bethe-Salpeter equation (GW-BSE) approach (12)], used to understand and compute excitonic effects in linear optical absorption, to study nonlinear optical responses. Different model approaches to investigate the effects of many-electron interactions on nonlinear optical responses of materials have been proposed. For instance, a Floquet-based model Hamiltonian formalism showed that excitonic effects enhance nonlinear response (13). In the specific case of second harmonic generation, first-principles approaches have been developed and applied to real materials, for instance, by making an approximation to the full many-body perturbation theory treatment (14, 15) or to the time-dependent density function theory, in which electron interaction effects are taken into account via simplified kernels (16). A real-time formulation based on propagating the time-dependent Schrodinger equation has also been developed (17) and applied to second harmonic generation (18). For shift currents in real materials, only one recent study considered the effects of excitons on the linear optical coefficient that might influence shift currents, but these authors included only the effects of excitons on the electromagnetic field profile in a bulk sample, and the crucial process of shift current generation itself is still treated within an independent-particle picture (11). Thus, there is still no first-principles calculation and understanding of the role of many-electron interactions, particularly those due to excitons, on shift currents.Here, we show from first principles that 1) bound exciton states in the band gap can generate substantial shift currents, and 2) excitonic effects in the electron–hole continuum part of the spectrum can also greatly enhance shift currents due to the enhancement of the optical matrix elements from the coherence of the electron–hole pairs and to interexciton couplings that arose in the nonlinear responses.     

《御纂医宗金鉴》伤科内治原则及方药应用特色探研

[目的]探求《御纂医宗金鉴》伤科内治原则及方药应用特色。[方法]运用文献法对《御纂医宗金鉴》伤科内治法相关内容进行研究,从辨治原则和方药应用两个角度进行归纳和分析,并举医案一则探讨该治法对临床的指导作用。[结果]《御纂医宗金鉴》伤科内治法以辨瘀血出血、辨病位为辨证要点;伤科的治疗原则包括瘀血从肝论治、分阶段论治、调畅情志、兼症施治;书中用方经典,多在用方时加用引药,并提出了"假其热以行其寒"的用药思想。所举验案诊为骨折脾虚肝郁、瘀血阻滞证,基于该理论,从肝论治伤科疼痛,治以疏肝健脾、活血通络,注重情志调节与兼症施治,故见收效。[结论]《御纂医宗金鉴》系统总结了伤科内治的辨治原则和方药应用,伤科内治注重辨瘀血出血及辨病位,治疗原则包括瘀血从肝论治、分阶段论治、调畅情志、兼症施治,用方时多加用引药,对于指导临床治疗伤科病症具有重要的参考价值。