转管机枪后坐对机心组传动系统的影响

为提高转管机枪的性能,研究了其后坐运动对机心组传动系统的影响。对机匣凸轮曲线槽与机心组主滚轮的三种状态进行了分析,依据动量矩定理列写机心组主滚轮运动微分方程。提出了在考虑后坐运动的前提下,机心组主滚轮提前横越冲击和逆传动的观点,探讨了转管机枪编程方案。将不同的间隙大小与是否考虑后坐运动进行组合。仿真实例表明:在考虑后坐运动及机心组主滚轮与机匣凸轮曲线槽之间装配间隙的情况下,机心组主滚轮会在几个短促的区间内突然换向,使其与机匣凸轮曲线槽的接触力突然增大,表现出与传统凸轮机构的加减速过程完全不同的特性;机匣凸轮曲线槽的磨损是由传动时的驱动压力和后坐运动的机心组主滚轮经常性的急刹车与快速换向造成的。

Belt or network?The spatial structure and shaping mechanism of the Great Wall cultural belt in Beijing

The relationship between cross-regional cultural landscapes does not currently receive enough attention in cultural landscape conservation. Cultural landscapes in China are faced with the crisis of fragmentation and islanding, which makes it necessary to strengthen the idea of integrated conservation. The Great Wall cultural belt in Beijing is a cross-regional linear cultural landscape in the northwest mountainous area of Beijing. With the Great Wall as a link connecting the surrounding natural, social, and cultural resources to form a banded structure, it has the typical and practical significance of integrated conservation. Based on the theory of the cultural landscape security pattern and its ‘node – setting – connection' model, this research studies the spatial structure and shaping mechanism of the Great Wall cultural belt in Beijing from the perspective of tourist flow, using Flickr geo-tagged photos and Wikiloc tracks. The results identify the core nodes and intermediate nodes of the Great Wall cultural belt in Beijing and show that it has a multicore, multi-group hierarchical nesting structure differing from the geographic space, which has groups following the evolution orbit of ‘linear string – circumnuclear star – complete network.' To explain the differences between the cultural association network(CAN) and the geospatial network(GSN), we find that the cultural associations between nodes rely on geophysical channels, including heritage corridors and traffic passages, as physical carriers, but the nodes' attraction and their setting elements, containing natural geography environments, settlements, administrative divisions, etc., change the channel resistance, so CAN and GSN present different characteristics. From the perspective of systematic and spatial network thoughts, this study has made an attempt to adopt new analysis and research methods to achieve the integrated conservation and inheritance of linear cultural landscapes in mountainous areas.

Atrial fibrosis： an obligatory component of arrhythmia mechanisms in atrial fibrillation？

Advances in clinical and fimdamental research, which have been promoted over last decades have led to a well- established understanding of atrial fibrillation （AF） as an epiphenomenon that despite similar manifestations may have different underlying mechanisms and thus require in- dividualized treatments. With rare exceptions of AF caused by mutations in genes coding ion channels in pa- tients with structurally normal atria, fibrotic replacement of atrial myocardium remains the comer stone of atrial pa- thology in patients with AF.

Numerical and Experimental Study of Steel Space Truss with Stamped Connection

Tubular section members made of steel are common in space trusses. There are several types of connections to attach these members. The most popular is the staking end-flattened connection. The reduced cost and the fast assemblage of the truss are among the advantages of the staking end-flattened connection on 3D trusses. However, such connections present disadvantages like eccentricities and stiffness weakening of the tubular members. In this work, based on computer simulations and experimental lab tests on prototypes, small changes on the staking end-flattened connections such as reinforcement and eccentricity correction are evaluated. The results show an increase of 68% for local collapse and 17% for global collapse in the truss load carrying capacity when the suggested changes proposed in this article are used for the staking end-flattened connections.

Multicenter clinical efficacy observation of integrated Traditional Chinese Medicine-Western Medicine treatment in acute onset period of pulmonary heart disease

OBJECTIVE: To evaluate the efficacy of integrated Traditional Chinese Medicine-Western Medicine(TCM-WM) in the treatment of acute onset pulmonary heart disease(PHD).METHODS: A total of 240 patients met the inclusion criteria and were enrolled. These inpatients were divided into group A(treatment group) and B(control group) in order of admission according to the principles of randomization and control. The research was performed simultaneously in three hospitals. Two groups were given basic treatment that included: controlled oxygen therapy, active and effective anti-infection, maintaining airway patency,correcting O_2 deficiency and CO_2 retention, correcting acid-base imbalance and electrolyte disturbance, reducing pulmonary hypertension and treating right heart failure, nutritional support and treatment of complications. Group A was given basic treatment and integrated Traditional Chinese Medi-cine(TCM) differentiating therapy; group B was given basic therapy and a placebo that was similar in appearance and taste to TCM medicinal broth of pharmaceutical preparations, provided by Yibin Pharmaceutical Company(Yibin, China, Wuliangye Group).RESULTS: The mortality in the treatment group decreased by 4.98% compared with the control group. The treatment group reported improved ventilation, corrected hypoxemia, improved nutritional status and promoted digestive functions. It also significantly improved the patient's self-life skills, improved the patient's quality of life and could shorten the length of hospital stay.CONCLUSION: Comprehensive integrated TCMWM treatment showed good clinical efficacy toward the acute onset period of PHD patients.

Supramolecular organizing centers(SMOCs) as signaling machines in innate immune activation

Innate immunity offers the first line of defense against infections and other types of danger such as tumorigenesis. Its discovery provides tremendous therapeutic opportunities for numerous human diseases. Delving into the structural basis of signal transduction by innate immune receptors, our lab has recently helped to establish the new paradigm in which innate immune receptors transduce ligand-binding signals through formation of higher-order assemblies containing intracellular adapters, signaling enzymes and their substrates. These large signalosome assemblies may be visible under light microscopy as punctate structures in the μm scale, connecting to the underlying molecular structures in the nm scale. They drive proximity-induced enzyme activation, and provide a mechanism for signaling amplification by nucleated polymerization. These supramolecular signaling complexes also open new questions on their cellular organization and mode of regulation, pose challenges to our methodology, and afford valuable implications in drug discovery against these medically important pathways.

Simulation Analysis of Factors Influencing Chiller EER

This study constructed a mathematic model of a variable frequency centrifugal chiller using Simulink software. By running the simulation, it was discovered that when the other factors are constant, the EER(Energy Efficiency Ratio) of the chiller increases with decreases in the temperature of the cooling water and increases in the temperature of the chilled water. The effect of changes in the cooling water temperature on the EER of the chiller is stronger than that of changes in the chilled water temperature. In addition, as the chiller load decreases, the EER increases until reaching a maximum, after which it decreases. Furthermore, the EER of chillers working under a constant flow rate is slightly higher than that of those working under varying flow rates.