Effect of system response on partial surge initiated instability in a transonic axial flow compressor

Partial surge is a type of instability inception in transonic compressors and occurs in the form of axisymmetric low-frequency disturbances localized in the hub region.Previous studies illustrate that the frequency of partial surge is set by the Helmholtz frequency of the entire system,which motivates to propose a hypothesis that the system response performs an important role in the formation of partial surge.For further verification,a series of experiments are conducted to explore the link between the propagating of the partial surge and the system feedback in this study.In the first case,an additional test point is set on the wall of the plenum to detect the system response.Combining the flow behaviors inside the plenum with the disturbances in the rotor tip and stator hub/tip regions,the effects of the system feedback on the occurrence of the continuous disturbances and the rotating stall cells are illustrated.In the second case,a screen is mounted at the compressor outlet to prevent positive feedback from the plenum.The experimental results demonstrate that in the absence of system feedback,it is the occurrence of spike-type stall inception that leads to the flow instability instead of that of partial surge.In addition,three flow phenomena in the second case are discussed,including the occurrence of the single pulse,the unstable process during the stall evolution and the switch of instability inception.

Effects and mechanisms of Helicobacter pylori infection on the occurrence of extra-gastric tumors

Helicobacter pylori(H.pylori)colonizes the human stomach and many studies have discussed the mechanisms of H.pylori infection leading to gastric diseases,including gastric cancer.Additionally,increasing data have shown that the infection of H.pylori may contribute to the development of extra-gastric diseases and tumors.Inflammation,systemic immune responses,microbiome disorders,and hypergastrinemia caused by H.pylori infection are associated with many extra-gastric malignancies.This review highlights recent discoveries;discusses the relationship between H.pylori and various extra-gastric tumors,such as colorectal cancer,lung cancer,cholangiocarcinoma,and gallbladder carcinoma;and explores the mechanisms of extra-gastric carcinogenesis by H.pylori.Overall,these findings refine our understanding of the pathogenic processes of H.pylori,provide guidance for the clinical treatment and management of H.pylori-related extra-gastric tumors,and help improve prognosis.

Tomato Root Response to Subsurface Drip Irrigation

Four depth treatments of subsurface drip irrigation pipes were designated as 1) at 20,2) 30 and 3) 40 cm depths all with a drip-proof flumes underneath,and 4) at 30 cm without a drip-proof flume to investigate the responses of a tomato root system to different technical parameters of subsurface drip irrigation in a glass greenhouse,to evaluate tomato growth as affected by subsurface drip irrigation,and to develop an integrated subsurface drip irrigation method for optimal tomato yield and water use in a glass greenhouse. Tomato seedlings were planted above the subsurface drip irrigation pipe. Most of the tomato roots in treatment 1 were found in the top 0-20 cm soil depth with weak root activity but with yield and water use efficiency (WUE) significantly less (P ---- 0.05) than treatment 2; root activity and tomato yield were significantly higher (P = 0.05) with treatment 3 compared to treatment 1; and with treatment 2 the tomato roots and shoots grew harmoniously with root activity,nutrient uptake,tomato yield and WUE significantly higher (P= 0.05) or as high as the other treatments. These findings suggested that subsurface drip irrigation with pipes at 30 cm depth with a drip-proof flume placed underneath was best for tomato production in greenhouses. In addition,the irrigation interval should be about 7-8 days and the irrigation rate should be set to 225 m3 ha-1 per event.

多自由度非线性系统动力响应时程分析技术

本文介绍多自由度非线性系统动力响应时程分析技术。在与频谱分析法等过去常用的动力响应分析法对比中说明了这一新方法的突出优点和发展现状。文中还给出了这一分析方法在核电设备地震响应分析中应用时的实例分析结果。

The responses of nursing system to the outbreak of SARS in a general hospital

Severe Acute Respiratory Syndrome (SARS), referred to as 'contagious atypical pneumonia' is the fastest spreading communicable disease known in recent history. This disease is different from other kinds of respiratory contagion due to the following aspects: the syndrome happens quickly and the infectivity is high. New problems encountered by the nursing management staff are the precipitate, pestiferous, and large numbers of in-patients and the understanding of appropriate responses, within large complex hospitals, to ensure patient care is actively supported and infectivity is prevented. To deal with these problems, we implemented the following strategies; reinforcement of the management system; optimization of the nursing flow; amendments to related hospital policies; collection of relevant information; adherence to stringent disinfection protocols; isolation of areas; reallocation of hospital resources and more efficient utilization of resources. The above strategies have reinforced the nursing management system's active response, guaranteed daily operation of the hospital's nursing activities, including the quality of care provided by the nurses, and ensured the health of patients, nurses and doctors.