Vibration test method of aero-engine 3D printing pre-swirl nozzle based on equivalent installation stiffness

Yujie Zhao,Yeda Lian,Lei Li,Xu Gong,Xianghai Chai,Wei Liu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2

Pre-swirl nozzle is an important cooling component that is located inside of aero-engine and exposed to complex vibration excitation, and exploring its vibration characteristics and durability is of significant importance, especially for 3D printing pre-swirl nozzle. The present study provides a novel vibration test method based on equivalent installation stiffness. Firstly, the vibration characteristics of pre-swirl nozzle in real engine assembly state is calculated by the finite element method, and the equivalent constraint fixture is designed and checked based on this. The check results indicate that the designed fixture can well restore the installation stiffness of engine and the strength of the test fixture elements is enough in the vibration test process. Then, the modal characteristics of pre-swirl nozzle are measured by modal test, based on which the accuracy of the finite element model is verified. Finally, a test program of vibration durability is established to evaluate the vibration durability of pre-swirl nozzle, in which the excitation frequency is determined by combining logarithmic frequency sweep and linear frequency sweep and the location of maximum stress is determined based on a novel method (density increasing method). Besides, the calibration of relation between vibration stress and excitation amplitude is completed. Based on the proposed test program, vibration durability test is performed. The results show that the natural frequency of pre-swirl nozzle only decreases by 0.62 % after 5×10 7 cycles, which indicates that the specimen is always in the stage of fatigue crack initiation over the test duration.

Elastic buckling performance of FG porous plates embedded between CNTRC piezoelectric patches based on a novel quasi 3D-HSDT in hygrothermal environment

Yujie Zhang,Zhihang Guo,Yimin Gong,Jianzhong Shi,Mohamed Hechmi El Ouni,Farhan Alhosny Techno-Press 2023 Advances in nano research Vol.15 No.2

The under-evaluation structure includes a functionally graded porous (FGP) core which is confined by two piezoelectric carbon nanotubes reinforced composite (CNTRC) layers. The whole structure rests on the Pasternak foundation. Using quasi-3D hyperbolic shear deformation theory, governing equations of a sandwich plate are driven. Moreover, face sheets are subjected to the electric field and the whole model is under thermal loading. The properties of all layers alter continuously along with thickness direction due to the CNTs and pores distributions. By conducting the current study, the results emerged in detail to assess the effects of different parameters on buckling of structure. As instance, it is revealed that highest and lowest critical buckling load and consequently stiffness, is due to the V-A and A-V CNTs dispersion type, respectively. Furthermore, it is revealed that by porosity coefficient enhancement, critical buckling load and consequently, stiffness reduces dramatically. Current paper results can be used in various high-tech industries as aerospace factories.

Pharmacokinetic difference of berberine between normal and chronic visceral hypersensitivity irritable bowel syndrome rats and its mechanism

Zipeng Gong,Ying Chen,Ruijie Zhang,Qing Yang,Yajie Wang,Yan Guo,Bingbing Zhou,Xiaogang Weng,Xuchen Liu,Yujie Li,Xiaoxin Zhu,Yu Dong 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.10

Berberine is one of active alkaloids from Rhizomacoptidis in traditional Chinese medicine. The pharmacokineticsof berberine in rat plasma were compared betweennormal and chronic visceral hypersensitivity irritable bowelsyndrome rats (CVH-IBS) established by mechanical colonirritation using angioplasty balloons for 2 weeks after oraladministration of berberine hydrochloride (25 mg/kg) withthe equivalent dose of 22 mg/kg for berberine according tobody weight. Immunohistochemical analysis of c-fos andmyosin light chain kinase (MLCK) and immunofluorescenceanalysis of MLCK in rat colon were conducted. Quantificationof berberine in rat plasma was achieved by using a sensitiveand rapidUPLC-MS/MSmethod. Plasma samples werecollected at 15 different points in time and the pharmacokineticparameters were analyzed by WinNonlin software. Thegreat different pharmacokinetic behavior of berberine wasobserved between normal and CVH-IBS model rats. Compared with normal group, T1/2 and AUC(0–t) of berberinein the model group were significantly increased, respectively(573.21 ± 127.53 vs 948.22 ± 388.57 min; 8,657.19 ±1,562.54 vs 11,415.12 ± 1,670.72 min.ng/ml). Cl/F of berberinein the model group significantly decreased, respectively(13.89 ± 1.69 vs 9.19 ± 2.91 L/h/kg). Additionally,the expressions of c-fos and MLCK in model group werehigher than those in normal group. The pharmacokinetic behaviorof berberine was significantly altered in CVH-IBSpathological conditions, which indicated the dosage modificationof berberine hydrochloride in CVH-IBS were necessary. Especially, improved exposure to berberine in ratplasma inCVH-IBSmodel rats was attributed to increased theexpression of MLCK.

Quantitative Analysis of Seismic Response of Rock Slopes Using Discontinuous Deformation Analysis - A Case Study

Wenjun Gong,Yunsheng Wang,Yujie Wang,Yonghong Luo 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.12

For the prevention and mitigation of hazards, it is crucial to quantitatively analyze the seismic response of rock slopes. However, only a few studies have quantitatively analyzed the seismic response of rock slopes; these studies have considered topographic effects only and have neglected geological site effects, such as impedance contrasts and fractures, which are important factors affecting the seismic response of rock slopes, as revealed by multiple recent phenomena. Therefore, this study primarily aims to investigate the possibility of employing a numerical model for quantitatively analyzing the seismic response of rock slopes by considering the geological site effects. Herein, a discrete element method, i.e., discontinuous deformation analysis (DDA), was employed for the dynamic analyses, and a well-monitored rock slope, Mount Dong, was selected as the case study. In the proposed DDA model, horizontal and vertical ground motions were applied simultaneously. The different weathering degrees of the Mount Dong rock layers were considered to reflect the impedance contrasts, and the penalty value at the fractures was altered according to the stiffness for reflecting the fracture effects. Furthermore, a set of optimal boundary settings, especially for DDA, were applied to handle seismic dynamic problems. Results show that DDA can quantitatively reflect the seismic response of Mount Dong along a single direction, such as the horizontal direction, which is sufficient to satisfy engineering requirements. The peak ground acceleration amplification analyses indicate that: 1) a strong impedance contrast is more important than topographic effects for the seismic response of Mount Dong; and 2) in addition to the impedance of rock layers, widely spread fractures also play an important role in contributing to the seismic response anisotropy of rock slopes. Finally, spectral amplification analyses reveal that the responses of the inner and surface portion of Mount Dong are significant in a low- and high-frequency range, respectively.

Piperine as a Potential Nutraceutical Agentfor Managing Diabetes and Its Complications: A Literature Review

Dan Su,Yujie Wang,Shan Xu,Lidan Tang,Hao Yang,Jinhong Gong 한국식품영양과학회 2023 Journal of medicinal food Vol.26 No.10

The global prevalence of diabetes and its related complications has increased drastically and is currently aworldwide health challenge. There is still an urgent need for safe and effective natural products and supplements as alternativeand/or adjunctive therapeutic interventions. Nowadays, people pay more and more attention to the nutritional and medicinalvalue of food ingredients. As one of the most widely employed spices in cooking, pepper also has novel medicinal valuesattributed to its main component, piperine (Pip). Pip is an amide alkaloid with pleiotropic properties such as antiinflammatory,antioxidant, anti-cancer, and other related activities. Recently, Pip has received increasing scientific attentiondue to its antidiabetic and related complication properties. However, the values of existing studies are limited due to beingscattered and unsystematic. The present study reviewed the therapeutic potential and possible mechanisms of Pip in diabetesand related complications, with the aim of providing promising candidates for the development of novel and effectivealternative and/or adjunctive nutraceutical agents for the management of diabetes.

Control Over the Branched Structures of Platinum Nanocrystals for Electrocatalytic Applications

Ma, Liang,Wang, Chengming,Gong, Ming,Liao, Lingwen,Long, Ran,Wang, Jinguo,Wu, Di,Zhong, Wei,Kim, Moon J.,Chen, Yanxia,Xie, Yi,Xiong, Yujie American Chemical Society 2012 ACS NANO Vol.6 No.11

<P>Structural control of branched nanocrystals allows tuning two parameters that are critical to their catalytic activitythe surface-to-volume ratio, and the number of atomic steps, ledges, and kinks on surface. In this work, we have developed a simple synthetic system that allows tailoring the numbers of branches in Pt nanocrystals by tuning the concentration of additional HCl. In the synthesis, HCl plays triple functions in tuning branched structures <I>via</I> oxidative etching: (i) the crystallinity of seeds and nanocrystals; (ii) the number of {111} or {100} faces provided for growth sites; (iii) the supply kinetics of freshly formed Pt atoms in solution. As a result, tunable Pt branched structurestripods, tetrapods, hexapods, and octopods with identical chemical environmentcan be rationally synthesized in a single system by simply altering the etching strength. The controllability in branched structures enables to reveal that their electrocatalytic performance can be optimized by constructing complex structures. Among various branched structures, Pt octopods exhibit particularly high activity in formic acid oxidation as compared with their counterparts and commercial Pt/C catalysts. It is anticipated that this work will open a door to design more complex nanostructures and to achieve specific functions for various applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2012/ancac3.2012.6.issue-11/nn304237u/production/images/medium/nn-2012-04237u_0010.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn304237u'>ACS Electronic Supporting Info</A></P>

Core gut microbiota in Jinhua pigs and its correlation with strain, farm and weaning age

Hua Yang,Yingping Xiao,Junjun Wang,Yun Xiang,Yujie Gong,Xueting Wen,Defa Li 한국미생물학회 2018 The journal of microbiology Vol.56 No.5

Gut microbial diversity and the core microbiota of the Jinhua pig, which is a traditional, slow-growing Chinese breed with a high body-fat content, were examined from a total of 105 fecal samples collected from 6 groups of pigs at 3 weaning ages that originated from 2 strains and were raised on 3 different pig farms. The bacterial community was analyzed following high-throughput pyrosequencing of 16S rRNA genes, and the fecal concentrations of short-chain fatty acids (SCFAs) were measured by gas chromatograph. Our results showed that Firmicutes and Bacteroidetes were the dominant phyla, and Lactobacillus, Streptococcus, Clostridium, SMB53, and Bifidobacterium were the most abundant genera. Fifteen predominant genera present in every Jinhua pig sample constituted a phylogenetic core microbiota and included the probiotics Lactobacillus and Bifidobacterium, and the SCFAproducing bacteria Clostridium, Prevotella, Bacteroides, Coprococcus, Roseburia, Ruminococcus, Blautia, and Butyricicoccus. Comparisons of the microbiota compositions and SCFA concentrations across the 6 groups of pigs demonstrated that genetic background and weaning age affected the structure of the gut microbiota more significantly than the farm. The relative abundance of the core genera in the pigs, including Lactobacillus, Clostridium, Prevotella, Bacteroides, Roseburia, Ruminococcus, Blautia, and Butyricicoccus varied dramatically in pigs among the 2 origins and 3 weaning ages, while Oscillospira, Megasphaera, Parabacteroides, and Corynebacterium differed among pigs from different farms. Interestingly, there was a more significant influence of strain and weaning age than of rearing farm on the SCFA concentrations. Therefore, strain and weaning age appear to be the more important factors shaping the intestinal microbiome of pigs.