Formation Mechanisms for (Cr,Co)7C3/(Cr,Co)23C6 Heterogeneous Precipitates and Stacking Faults Around Carbides in Surfacing Welding of Stellite Alloy on Stainless Steel

Jiankun Xiong,Haibo Zhang,Fuheng Nie,Fen He,Jianping Yang,Zhan Hu,Zhongbo Wen,Haiyan Zhao,Xinjian Yuan 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

The formation mechanisms for two carbides with co-existence and increasing stacking faults nearby the carbides duringsurfacing welding were investigated in this study. The results indicated that the surfacing layer had a two-phase structure ofa matrix phase and a second phase, the density of the second phase was relatively small and the second phase was discontinuous,by contrast with the as-received welding wire. Relatively uniform microstructure of surfacing layer and the weldinginterface without melting of base metal were obtained, resulting in an inapparent change in the microhardness. A few carbideswith blocky shape were identified in the surfacing layer. The mechanisms for (Cr,Co)23C6 of face-centered cubic crystalstructure co-existing with (Cr,Co)7C3 of hexagonal close-packed crystal structure and (Cr,Co)23C6 subsequently forming closeto the pre-formed (Cr,Co)7C3 during the cooling process were discussed in alloying element, calculated equilibrium phasediagram, Gibbs energy, etc. The relatively higher density of the stacking fault present around the carbides was understoodfrom forming energy of stacking faults.

Silencing of Fanconi Anemia Complementation Group F Exhibits Potent Chemosensitization of Mitomycin C Activity in Breast Cancer Cells

Jiankun Yu,Lin Zhao,Yanlin Li,Na Li,Miao He,Xuefeng Bai,Zhaojin Yu,Zhihong Zheng,Xiaoyi Mi,En-Hua Wang,Minjie Wei 한국유방암학회 2013 Journal of breast cancer Vol.16 No.3

Purpose: Fanconi anemia complementation group F (FANCF) is a key factor to maintaining the function of Fanconi anaemia/BRCA (FA/BRCA) pathway, a DNA-damage response pathway. However,the functional role of FANCF in breast cancer has not been elucidated. In the present study, we evaluated the chemosensitization effect of FANCF in breast cancer cells. Methods: We performed specific knockdown of the endogenous FANCF in breast cancer cells by transfecting the cells with an FANCF short hairpin RNA (shRNA) vector. Cell viability was measured with a Cell Counting Kit-8, and DNA damage was assessed with the alkaline comet assay. The apoptosis, cell cycle, and drug accumulation were measured by flow cytometric analysis. Protein expression levels were determined by Western blot analysis, using specific antibodies. Results: The analyses of two breast cancer cell lines (MCF-7 and MDA-MB-435S) demonstrated that the FANCF shRNA could effectively block the FA/BRCA pathway through the inhibition of Fanconi anemia complementation group D2ubiquitination. Moreover, FANCF silencing potentiated the sensitivity of cells to mitomycin C (MMC), where combined FANCF shRNA/MMC treatment inhibited cell proliferation, induced Sphase arrest, apoptosis, and DNA fragmentation, and reduced the mitochondrial membrane potential, compared with MMC treatment alone. Conclusion: Taken together, this study demonstrates that the inhibition of FANCF by its shRNA leads to a synergistic enhancement of MMC cytotoxicity in breast cancer cells. These results suggest that the inhibition of the FA/BRCA pathway is a useful adjunct to cytotoxic chemotherapy for the treatment of breast cancer.

An IPD-based Incentive Mechanism to Eliminate Change Orders in Construction Projects in China

Jiankun Ma,Zhiliang Ma,Jiulin Li 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.7

As in other countries where DBB (Design-Bid-Build) is used, one of the major problems in construction projects in China is cost overrun, and its main cause is change orders that occur during the construction phase. As a new mode of project delivery, IPD (Integrated Project Delivery) is considered capable of solving major problems including change orders in construction projects by involving contractors in the design phase to optimize design results and by introducing an incentive mechanism through which cost savings are shared among participants. However, the existing incentive mechanisms are difficult to adapt in China because contractors rely on change orders to obtain profit from construction projects. This research aims to establish an IPD-based incentive mechanism to eliminate change orders in construction projects in China. First, the final account statement of a completed construction project was analyzed to obtain the economic law of change orders. Second, based on this economic law, this research established an incentive mechanism composed of a compensation method for contractors, another compensation method for designers and a method for calculating their parameters. Finally, 21 completed construction projects and a new construction project were used to validate the incentive mechanism. This research provides not only an applicable IPD-based incentive mechanism to eliminate change orders in construction projects in China but also provides an approach for applying IPD in any other country where DBB is used and where the existing IPD incentive mechanisms cannot be directly applied.

Effect of blade tip pattern on blade load and vibration characteristics of a twin-stage axial flow fan

Jiankun Zhang,Haihu Liu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.7

Focusing on a twin-stage axial fan, this paper investigates the effect of blade tip pattern on blade load and vibration characteristics. Steady simulations are first conducted to quantify the aerodynamic performance of various blade tip patterns. The finite element modeling analysis is performed to capture blade load and vibration characteristics, and Campbell diagram is introduced to evaluate resonance margin of different blade tip patterns. Results show that for all selected patterns, the first three mode shapes are mainly the bending of blade tip, which results in stress concentration at the blade root, while the last three are the waving in small range. The proposed blade tip patterns not only increase maximum stress and average deformation, but also significantly increase resonance margin near the rated speed. In addition, based on the harmonic response analysis, we find that the stress and amplitude frequency response will be notably altered by blade tip patterns.

Flexibility and Thermal Storage Properties of Polyurethane Adhesive Supported Phase Change Composites Based on Polyurethane Phase Change Materials

Jiankun Dong,Wenzhao Shi,Jinshu Liu,Shaofeng Lu,Hongjuan Zhou,Shanshan Cui,Manyan Zhang,Guoxin Su 한국섬유공학회 2023 Fibers and polymers Vol.24 No.9

Polyurethane phase change materials (PUPCMs) have been extensively applied in smart textiles and wearable electronic devices because of their excellent energy storage capacity. To realize the flexibility of PUPCMs for certain deformation and compact contact with objects, suitable support structures have been chosen to prepare polyurethane phase change composites (PUFPCCs) with energy storage capacity and device-level flexibility. In this work, PUPCM was prepared by the prepolymer method with polyethylene glycol (PEG) as the soft segment, 4,4-dicyclohexylmethane diisocyanate (HMDI) and 1,2-hexanediol as the hard segment. And polyurethane-based adhesives (PUA) were chosen to provide a support structure for PUFPCCs by physically blending and casting with prepared PUPCM. PUFPCCs showed good flexibility attributed to the film-forming performance of polyurethane-based adhesive in the composites. The chemical structure, crystallization properties, phase transformation properties and thermal stability of the prepared PUPCM and PUFPCCs were investigated via Fourier transform infrared spectroscopy (FT-IR), 1H NMR spectroscopy, X-ray diffraction (XRD), polarizing optical microscope (POM), differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis respectively. The phase change temperature of PUFPCCs ranged from 36 to 40 ℃. The maximum enthalpy value of PUFPCCs was up to 40 J/g for daily application. Moreover, the thermal stability of PUPCM was improved attribute to the support structure of PUA in PUFPCCs. Therefore, the prepared PUFPCCs have great potential for application in flexible wearable devices due to their excellent flexibility, suitable phase transition temperature close to human body temperature, high enthalpy value and improved thermal stability.

Decentralized Active Vibration Control Systems for Multi Degree of Freedom Structures

Jiankun Wang,Zenta Iwai,Mingcong Deng 제어로봇시스템학회 1999 제어로봇시스템학회 국내학술대회 논문집 Vol.5 No.10

Research on a High Power Inverter with Low Frequency Modulation Index by Selective Harmonic Mitigation Technique

Jiankun Cao,Shaojun Xie,Jinming Xu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

This paper proposes a generalized high power inverter scheme based on hybrid asymmetric cascaded topology with low frequency modulation index (FMI) control. Selective harmonic mitigation technique is combined with low order harmonic elimination control strategy for limiting the top 50 low order harmonics into the setting values, which reduces the size and weight of the output filter observably. The proposed inverter scheme of low FMI is suitable for high power applications. The single harmonic distortion (SHD) of low order harmonics can be restricted by different standards according to corresponding industry field.

Characteristics of Solid-state Fermented Feed and its Effects on Performance and Nutrient Digestibility in Growing-finishing Pigs

Hu, Jiankun,Lu, Wenqing,Wang, Chunlin,Zhu, Ronghua,Qiao, Jiayun Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.11

This study investigated the effects of solid-state fermentation of a compound pig feed on its microbial and nutritional characteristics as well as on pig performance and nutrient digestibility. A mixed culture containing Lactobacillus fermentum, Saccharomyces cerevisae and Bacillus subtilis was used for solid-state fermentation and solid-state fermented feed samples were collected on days 0, 1, 2, 3, 5, 7, 10, 15, 20 and 30 for microbial counts and chemical analysis. Lactic acid bacteria increased rapidly during the first three days of fermentation and then slowly declined until day 10 and, thereafter, the counts were maintained at about 6.7 log cfu/g for the duration of the fermentation period. Enterobacteria also increased during the first two days, and then fell below the detectable level of the analysis (3.0 log cfu/g). The pH of the fermentation substrate declined from 6.1 at the start of fermentation to 5.7 by day 30. The water-soluble protein content increased from 8.2 to 9.2% while the concentration of acetic acid increased from 16.6 to 51.3 mmol/kg over the 30-day fermentation. At the end of the 30-day fermentation, the solid-state fermented feed was used in a pig feeding trial to determine its effects on performance and nutrient digestibility in growing-finishing pigs. Twenty crossbred barrows ($14.11{\pm}0.77kg\;BW$) were allotted into two dietary treatments, which comprised a regular dry diet containing antibiotics and a solid-state fermented feed based diet, free of antibiotics. There was no difference due to diet on pig performance or nutrient digestibility. In conclusion, solid-state fermentation resulted in high counts of lactic acid bacteria and low counts of enterobacteria in the substrate. Moreover, feeding a diet containing solid-state fermented feed, free of antibiotics, can result in similar performance and nutrient digestibility in growing-finishing pigs to a regular diet with antibiotics.

Role of Microstructure on the Shock-Induced Strengthening Behavior of Ti–6Al–4V Alloy

Yu Ren,Jiankun Lin 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

The influence of microstructure on the shock-induced strengthening behavior of Ti–6Al–4V (Ti-64) alloy was systematicallyinvestigated through plate impact experiments and quasi-static reload compression tests. Ti-64 displays no enhancedshock-induced strengthening effect at equivalent strain, regardless of the microstructure and shock stress amplitude. However,the shock-induced enhancement ratio is higher in the alloy having the bimodal microstructure with high equiaxed primaryα-phase (P ) volume fraction or the lamellar microstructure with wide α-platelets. The microstructure analyses show thatthe substructures of the postshock Ti-64 with both bimodal and lamellar microstructures are dominated by planar slip. Dislocations are easier to nucleate, move and tangle in those large-sized α phases, such as equiaxedP and wide α-platelet,leading to the formation of reticular substructures and slip bands. However, the dislocation density is relatively low in thesmall α plate of the transformed β regions and in the narrow α-platelet, which is attributed to the relaxation of shock stressand consequently to the suppression of dislocation nucleation caused by the obvious grain/phase boundary damping effect. Only a small number of twins were formed in the lamellar microstructure with wide α-platelet, indicating that grain size andinterface damping also affect the twinning behavior of Ti-64 under shock loading conditions.

The Mechanical Properties of Lean Clay Filler under Freeze-thaw and Thermostatic Curing Cycles in Loess Plateau

Xiaoqiang Liu,Jiankun Liu,Yahu Tian,Yupeng Shen,Dan Chang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.4

The subgrade filler weakens its mechanical property after suffering from freeze-thaw (F-T) cycles, which threatens the trains' operation safety. It is essential to study the filler's mechanical property's evolution with the F-T cycles and reveal the test factors' incidence on the mechanical parameters. This study conducted a series of unconsolidated and undrained (UU) triaxial shear tests in the F-T and thermostatic-curing (T-C) groups, considering the temperature, confining pressure, and cycle times. As the control group, the T-C group can more prominently reflect the F-T effects on the soil's mechanical parameters, including the stress-strain curve, shear strength, and strength index. A piecewise and linear function can fit internal friction angle or cohesion's change with cycle times, respectively. The fitting parameters reflect the T-C and F-T effects on soil's mechanical properties. The absolute degree of incidence reveals the correlation between mechanical parameters and test factors. The -15°C has the most significant incidence than -5°C and 20°C in shear strength, while -5°C has the most considerable incidence than -15°C and 20°C in friction angle or cohesion. The water distribution and volume expansion due to the F-T cycles are the main reasons determining mechanical properties' evolution with the cycle times in different negative temperatures.