Austenite Grain Growth Behavior of 30BF Steel Before Rough Rolling

Yong‑feng Chen,Jian‑bo Xie,Yan‑xin Wu,Jian‑xun Fu 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

To investigate the eff ect of heat treatment on the grain size of austenite in 30BF steel, the comparisons of the morphologiesand sizes of austenite grains between heating samples were made with a high-temperature electric resistance furnace, andthe austenite growth models were built with method of mathematics. The results show that most grains in original specimenwith the sizes below 70 μm uniformly distributed. At a heating rate ( v ) of 10 °C/s, the grain size ( d ) value under a certain time( t ) increased by 60–100 μm with raising temperature ( T ) from 850 to 1100 °C, whereas the d value under a certain T merelyincreased by 70–120 μm with raising time to 60 min. Under v = 0.1 °C/s, T = 850 °C, and t = 0 s, the occupied ratio of grainswith sizes of 40–50 μm was 0.165, whereas at 900 °C, the occupied ratio was 0.125. The evolutions of ln (d5.8− d5.80 ) with1/ T were in negative linear correlations, whereas the ln (d5.8− d5.80 ) with ln t were in positive linear correlations. To sum up,the grain growth behavior of steel was elucidated.

MiR-421 Regulates Apoptosis of BGC-823 Gastric Cancer Cells by Targeting Caspase-3

Wu, Jian-Hong,Yao, Yong-Liang,Gu, Tao,Wang, Ze-You,Pu, Xiong-Yong,Sun, Wang-Wei,Zhang, Xian,Jiang, Yi-Biao,Wang, Jian-Jun Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.13

MicroRNAs might act as oncogenes or tumor suppressors in cancer. Recent studies have shown that miR-421 is up-regulated in human gastric cancer. Here, we found that miR-421 was over-expressed in gastric cancer tissues and cell lines. Bioinformatics analysis predicted that the caspase-3 gene was a target of miR-421. Caspase-3 was negatively regulated by miR-421 at the post-transcriptional level. Bax and Bcl-2 were also regulated by miR-421. Moreover, tumor necrosis factor receptor-I and -II, death receptors in the apoptosis pathway, were up-regulated by miR-421. The over-expression of miR-421 promoted gastric cancer cell growth and inhibited apoptosis of the BGC-823 gastric cancer cell line. These observations indicate that miR-421 acts as a tumor promoter by targeting the caspase-3 gene and preventing apoptosis of gastric cancer cells through inhibition of caspase-3 expression. These findings contribute to our understanding of the functions of miR-421 in gastric cancer.

Contact finite element method for dynamic meshing characteristics analysis of continuous engaged gear drives

Yong-jun Wu,Jian-jun Wang,Qin-kai Han 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.6

The dynamic meshing characteristics of gear drives have been a major concern in the design of power transmission systems as they affect vibration, acoustic noise, durability and efficiency. Gaining a more comprehensive understanding of the dynamic meshing characteristics of continuous engaged gear drives is a key to the development of power transmission systems. In this paper, a dynamic contact finite element analysis method, considering the variation of the engaged teeth pairs, the loaded elastic and contact deformations, and the sliding friction, is presented for the dynamic meshing characteristics analysis of continuous and elastic engaged gear drives. Various kinds of continuous engaged gear models under low and high speed condition are simulated and compared using the presented method. The tooth profile modification was designed based on the simulation results. Moreover, the effects of the tooth profile modification, the sliding friction and the time-varying meshing stiffness upon the dynamic meshing characteristics of continuous engaged gear drives are discussed in detail. The results show that the method is not only effective in designing and evaluating the tooth profile modification, but also in studying the dynamic meshing characteristics of continuous engaged gear drives with realistic time-varying meshing stiffness and tooth sliding friction. The present method could provide an effective tool for vibration mechanism study and dynamic design of the continuous engaged gear drives considering more influence factors.

Dual-pumped nondegenerate four-wave mixing in semiconductor laser with a built-in external cavity

Wu, Jian-Wei,Qiu, Qi,Hyub Won, Yong IOP 2017 Journal of optics Vol.19 No.4

<P>In this paper, a semiconductor laser system consisting of a conventional multimode Fabry–Pérot laser diode with a built-in external cavity is presented and demonstrated. More than two resonance modes, whose peak levels are significantly higher than other residual modes, are simultaneously supported and output by adjusting the bias current and operating temperature of the active region. Based on this device, dual-pumped nondegenerate four-wave mixing—in which two pump waves and a single signal wave are simultaneously fed into the laser, and the injection power and wavelength of the injected pump and signal waves are changed—is observed and discussed thoroughly. The results show that while the wavelengths of pump wave A and signal wave S are kept constant, the other pump wave B jumps from about 1535 nm to 1578 nm, generating conversion signals with changed wavelengths. The achieved conversion bandwidth between the primary signal and the converted signal waves is broadly tunable in the range of several terahertz frequencies. Both the conversion efficiency and optical signal-to-noise ratio of the newly generated conversion signals are adopted to evaluate the performance of the proposed four-wave mixing process, and are strongly dependent on the wavelength and power of the injected waves. Here, the attained maximum conversion efficiency and optical signal-to-noise ratio are close to −22 dB and 15 dB, respectively.</P>

Optically tunable microwave, millimeter-wave and submillimeter-wave utilizing single-mode Fabry-Pérot laser diode subject to optical feedback

Wu, Jian-Wei,Nakarmi, Bikash,Won, Yong Hyub The Optical Society 2016 Optics express Vol.24 No.3

<P>In this paper, we use optical feedback injection technique to generate tunable microwave, millimeter-wave and submillimeter-wave signals using single-mode Fabry-Perot laser diode. The beat frequency of the proposed generator ranges from 30.4 GHz to 3.40 THz. The peak power ratio between two resonating modes at the output spectrum of can be less than 0.5 dB by judiciously selecting feedback wavelength. In the stabilization test, the peak fluctuation of photonic signal is as low as 0.19 dB within half hour. Aside from locking regions, where the laser is easily locked by the injection beam, the side-mode suppression ratio is well over 25 dB with the maximum value of 36.6 dB at 30.4 GHz beat frequency. In addition, the minimum beat frequency interval between two adjacent photonic signals is as low as 10 GHz. (C) 2016 Optical Society of America</P>

Static/dynamic contact FEA and experimental study for tooth profile modification of helical gears

Yong-jun Wu,Jian-jun Wang,Qin-kai Han 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.5

"With the development of high-performance computers, the contact finite element analysis (FEA) method has become more and more popular for studying both the static and dynamic behaviors of gear drives. In this paper, a precise tooth profile modification (TPM) approach of the helical gear pairs is presented first. The type and amount of the TPM are accurately determined by the static contact FEA results. Then dynamic contact simulations for the helical gear pairs with and without TPM are, respectively, carried out to evaluate the effect of the presented TPM approach on vibration reduction. No additional assumptions and simplifications are required for the static and dynamic contact analysis models. Vibration comparison experiments are also carried out on an open power flow test rig. Both the simulated and experimental results show that the presented precise TPM of helical gears is effective on vibration reduction around the working load, and the dynamic contact simulation is effective in estimating the effect of the TPM on vibration reduction in the designing stage."

Molecular and cytological evidences for the natural wheatgrass hybrids occurrence and origin in west China

Jian Zeng,Xing Fan,Hai-Qin Zhang,Li-Na Sha,Hou-Yang Kang,Li Zhang,Rui-Wu Yang,Chun-Bang Ding,Yong-Hong Zhou 한국유전학회 2012 Genes & Genomics Vol.34 No.5

Interspecies hybridization has been frequently observed in the tribe Triticeae. Natural hybridization between Kengyilia and Roegneria or Elymus species has not been reported as yet. Several sterile wheatgrass individuals exhibiting intermediately morphological traits between Kengyilia and Roegneria or Elymus species were identified in the meadow of Sichuan and Gansu provinces in China, suggesting their natural hybrid origin. The putative hybrids were analyzed by using the sequences of ITS and trnH-psbA together with cytological observation in order to assess the origin of hybrids. Both ITS and cytological data revealed the evidence of allopolyploid origin and confirmed the presence of StStYYP and StStYYHP genomes in the putative natural hybrids. The data suggest that the StStYYP hybrid originated from hybridization between Kengyilia and Roegneria and the hybrid with StStYYHP originated from hybridization between Kengyilia and Elymus. Chloroplast sequence data demonstrated that K. rigidula and K. melanthera were the likely maternal donors in the hybridization events.

An improved resonantly driven piezoelectric gas pump

Yue Wu,Yong Liu,Jian-Fang Liu,Long Wang,Xiaoyang Jiao,Zhigang Yang 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.3

Piezoelectric pumps have the potential to be used in a variety of applications, such as in air circulation and compression. However, piezoelectric membrane pumps do not have enough driving capacity, and the heat induced during the direct contact between the driving part and the gas medium cannot be dissipated smoothly. When the gas is blocked, the piezoelectric vibrator generates heat quickly, which may eventually lead to damage. Resonantly driven piezoelectric stack pumps have high performance but no price advantage. In this situation, a novel, resonantly driven piezoelectric gas pump with annular bimorph as the driver is presented. In the study, the working principle of the novel pump was analyzed, the vibration mechanics model was deter-mined, and the displacement amplified theory was studied. The outcome indicates that the displacement amplification factor is related with the original displacement provided by the piezoelectric bimorph. In addition, the displacement amplification effect is related to the stiffness of the spring lamination, adjustment spring, and piezoelectric vibrator, as well as to the systematic damping factor and the driving frequency. The experimental prototypes of the proposed pump were designed, and the displacement amplification effect and gas output performance were measured. At 70 V of sinusoidal AC driving voltage, the improved pump amplified the piezoelectric vibrator displacement by 4.2 times, the maximum gas output flow rate reached 1685 ml/min, and the temperature of the bimorph remained normal after 2000 hours of operation when the gas medium was blocked.

Application of Joint Detection of AFP, CA19-9, CA125 and CEA in Identification and Diagnosis of Cholangiocarcinoma

Li, Yong,Li, Da-Jiang,Chen, Jian,Liu, Wei,Li, Jian-Wei,Jiang, Peng,Zhao, Xin,Guo, Fei,Li, Xiao-Wu,Wang, Shu-Guang Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.8

Objective: To explore the application of joint detection of serum AFP, CA19-9, CA125 and CEA in identification and diagnosis of cholangiocarcinoma (CC). Materials and Methods: The levels of serum AFP, CA19-9, CA125 and CEA of both 30 patients with CC and 30 patients with hepatocellular carcinoma (HCC) were assessed. Receiver operating characteristic (ROC) curves were used to evaluate the diagnostic effects of single and joint detection of those 4 kinds of tumor markers for CC. Results: The levels of serum CA19-9, CA125 and CEA in CC patients were higher than that in HCC patients,whereas that of serum AFP was significantly lower s. The area under ROC curve of single detection of serum AFP, CA19-9, CA125 and CEA were 0.05, 0.86, 0.84 and 0.83, with the optimal cutoff values of 15.4 ng/ml, 125.1 U/ml, 95.7 U/ml and 25.9 ng/ml, correspondingly, and the percentage correct single diagnosis was <79%. With joint detection, the diagnostic effect of combined AFP, CA19-9, CA125 and CEA was the highest, with an area under the ROC curve of 0.94 (95%CI 0.88~0.99). Conclusions: Single detection of serum CA19-9, CA125 and EA is not meaningful. The sensitivity, specificity, the rate of correct diagnosis and the area under ROC curve of joint detection of AFP, CA19-9, CA125 and CEA are highest, indicating that the joint detection of these 4 tumor markers is of great importance in the diagnosis of CC.

Fabrication of Porous Silicon Nanotips by Using Argon Ion-beam Irradiation

Chang Yong Zhan,Yu Zou,Jian-Chun Wu,P. K. Chu 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.2

Porous silicon nanotips (NTs) are promising in many applications such as field emission, superhydrophobicity,solar cells and photoluminescence. Ion irradiation can create unique nanostructures in many types of materials at room temperature, and this paper reports the surface morphology of porous silicon irradiated by an Ar+ ion beam. Different porous silicons are irradiated, and the effects of the ion’s angle of incidence on the porous silicon nanostructure are investigated. Highdensity NTs of less than 50 nm in size are observed on the porous silicon. The NT size increases,but NT density decreases, with increasing pore size. The orientation of the NTs can be controlled by adjusting the ion impact. Our results reveal that the NTs located at the thick wall between pores and charges created on the tip during Ar+ ion irradiation are beneficial to the formation of the NTs.