Study on Dynamic Mechanical Properties of Limestone under Uniaxial Impact Compressive Loads

The dynamic mechanical properties of limestone are studied with 5 types of impact pressure acting on limestone samples in axial direction in this paper. The rubber shaper with a diameter of 5 mm and thickness of 2 mm is adopted. Besides the conical punch of split pressure bar of Hopkinson with a diameter of 50 mm is also used. The half-sinusoid pulse is obtained by using the pulse shaper method and special punch method; the constant strain rate deformation of the sample is realized. Dynamic compressive properties and failure modes of limestone under different impact pressure are investigated. In addition, energy dissipation is studied in the process of experiment. The results show that the dynamic compressive strength of limestone has an exponent relation to strain rate. The failure strain, degree of fragmentation, incident energy, and absorption energy increase, while the energy absorbency decreases with the increasing of strain rate. However, the initial elastic modulus is not sensitive to the strain rate. The research method and conclusions have reference value for the dynamic mechanical properties of other brittle materials

Emergence of central recirculation zone in a V-shaped premixed swirling flame

This paper presents an experimental study on the emergence of the central recirculation zone (CRZ) in a V-shaped premixed swirling flame, using simultaneous measurement of particle image velocimetry (PIV) and CH* chemiluminescence. The results show that either increasing the Reynolds number (Re) or decreasing the equivalence ratio ({\phi}) would facilitate the emergence of CRZ, and the inner shear layer (ISL) plays an essential role in governing the characteristics of CRZ. Further analysis demonstrates that the CRZ emergence can be promoted by higher ISL intensity but suppressed by enhanced viscous diffusion owing to higher flame temperature. As such, the CRZ formation can be interpreted as the outcome of a competition between the ISL intensity, i.e., circulation, and the vorticity consumption due to viscous diffusion. This competition physically corresponds to a special Reynolds number, Re_s, defined as the ratio between the ISL circulation ({\Gamma}) and the ISL effective viscosity ({\nu}_s), with a simplified heat loss model proposed for the temperature and viscosity estimations of the ISL. The outputting {\Gamma}-{\nu}_s plot yields a single boundary line separating the cases with and without CRZ, which points to a common critical Re_s of about 637, justifying the generality of the present criterion for lean-premixed V-shaped swirling flames of various operating conditions. Unlike most previous works which study the CRZ of a swirling flame from the point of vortex breakdown, the present work reveals the importance of enhanced viscous diffusion, caused by flame heating, in suppressing the CRZ emergence

得气客观化研究的思路和展望

The distinctions and relations between Deqi and acupuncture sensation should be distinguished in the objective researches of Deqi. In order to fully explore the relationship among the acupuncture sensation, Deqi and acupuncture curative effect, it is necessary to contrast the curative effect and body response induced by Deqi, unique sensations experienced by the acupunturist, unique sensations experienced by the patient, and stimulation without acupuncture sensation. Strategies and prospects about Deqi research are proposed as follows: (1) Researches of Deqi, such as how to induce Deqi, the influence factors of Deqi, the biological mechanism of Deqi, and so on, should be aimed at good stability of acupuncture curative effect, thus providing scientific evidence for clinical practice. (2) It is essential to introduce objective unified standards to evaluate the curative effect of acupuncture. However, the objective indicator selected in the researches should reflect the correlation between acupuncture curative effect and itself. (3)The acupuncturist manipulation, the physiological and psychological state of the patient, and the environmental factors are all the important factors that affect acupuncture, should be identified in the scientific and clinical research about the scientific research results, the clinical curative effect. should be identified in the scientific and clinical research about the scientific research results, the clinical curative effect,should be identified in scientific research result and the clinical curative effect (4) Some characteristics of the acupuncture treatment in traditional Chinese medicine theory can be used as the emphasis in the objective research of Deqi in the future. Characteristics of acupuncture, such as governing and regulating the spirit, acupuncture points, meridian specificity, distal function, bi-direction regulation function and so on, can be used as the entry point in the objective research of Deqi in the future.得气的客观化研究中应明确得气与针感的区别及联系，有必要将得气针刺（医者、患者针感均出现）、仅出现医者针感的针刺、仅出现患者针感的针刺、无针感刺激下的疗效及机体反应进行对比，以期全面探讨针感、得气及针刺疗效之间的关系。提出得气研究的策略和前景如下：（1）关于得气的研究，例如如何促使得气，有哪些因素影响得气，以及揭示得气的生物学机制等，应以良好稳定的针刺疗效为目的，从而为临床提供证据和科学依据。（2）需对针刺疗效进行评价，并引入相对客观统一的针刺疗效评价标准，研究所选取的反应得气的客观指标应当体现出其与针刺疗效之间的相关性。（3）医者针刺手法、患者生理及心理状态、环境因素是影响针刺得气的重要因素，科研及临床中应辨明这些因素对于科研结果、临床疗效的影响。（4）传统中医理论中针刺治疗的一些特性可作为今后得气客观化研究的重点，治神调神，腧穴、经络特异性，远治作用，双向良性调整作用等针刺疗法的特点可作为今后得气研究的切入点

The Fumigating Activity of Litsea cubeba oil and Citral on Solenopsis invicta

This paper studied the fumigating activity of Litsea cubeba oil and citral on Solenopsis invicta, identified and analyzed the chemical constituents and volatile components of L. cubeba oil via solid-phase microextraction which were then identified via gas chromatography-mass spectrometry. The results showed that citral and (z)-3,7-dimethylocta-2,6-diena were the main components of L. cubeba oil, as well as its volatile compounds. According to the experimental results, L. cubeba oil and citral had good fumigating activity on workers, and also had significant inhibition on the walking ability and climbing ability of workers. At the same time, the effects of the two agentia on the fumigating activity and behavioral inhibition of microergate were stronger than those of macroergate. After treating with L. cubeba oil and citral for 24 hours, the walking rate and grasping rate of microergate were both 0 %. The results showed that L. cubeba oil and citral had good control effect on S. invicta

Insights into midgut cell types and their crucial role in antiviral immunity in the lepidopteran model Bombyx mori

The midgut, a vital component of the digestive system in arthropods, serves as an interface between ingested food and the insect’s physiology, playing a pivotal role in nutrient absorption and immune defense mechanisms. Distinct cell types, including columnar, enteroendocrine, goblet and regenerative cells, comprise the midgut in insects and contribute to its robust immune response. Enterocytes/columnar cells, the primary absorptive cells, facilitate the immune response through enzyme secretions, while regenerative cells play a crucial role in maintaining midgut integrity by continuously replenishing damaged cells and maintaining the continuity of the immune defense. The peritrophic membrane is vital to the insect’s innate immunity, shielding the midgut from pathogens and abrasive food particles. Midgut juice, a mixture of digestive enzymes and antimicrobial factors, further contributes to the insect’s immune defense, helping the insect to combat invading pathogens and regulate the midgut microbial community. The cutting-edge single-cell transcriptomics also unveiled previously unrecognized subpopulations within the insect midgut cells and elucidated the striking similarities between the gastrointestinal tracts of insects and higher mammals. Understanding the intricate interplay between midgut cell types provides valuable insights into insect immunity. This review provides a solid foundation for unraveling the complex roles of the midgut, not only in digestion but also in immunity. Moreover, this review will discuss the novel immune strategies led by the midgut employed by insects to combat invading pathogens, ultimately contributing to the broader understanding of insect physiology and defense mechanisms