Investigation of Quench Sensitivity and Microstructure Evolution During Isothermal Treatment in 2195 Al–Li Alloy

Zhiwu Zhang,Youping Yi,Wen You,Shiquan Huang,Yonglin Guo,Hailin He 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

To investigate the quenching sensitivity of the 2195 Al–Li alloy rolled sheet and guide the design of the quenching process,the time–temperature-property (TTP) curves of this material were researched through interrupted quenching experiments. The differential scanning calorimetry (DSC) and transmission electron microscope (TEM) were used to characterize theevolution of precipitates during isothermal treatment. The results of this essay demonstrated that the nose temperature of 2195Al–Li alloy is around 370 °C and the temperature range of quenching sensitivity is 340 °C to 400 °C. The microstructureobservation revealed that the T1particles precipitate and grow rapidly at the temperature from 340 to 400 °C, which is dueto the high nucleation rate of phase and fast solute diffusion kinetics, especially at the nose temperature. The needle-shapedθ′/θ″ and T1particles grow up quickly as the isothermal preservation time prolonged, leading to the decrease of the supersaturatedsolid solution of the matrix. This will reduce the number of the age-induced precipitate and weaken the subsequentage hardening effect. Therefore, the rate of cooling should be increased in the quenching sensitivity range (340–400 °C) toinhibit the precipitation of the second phase and obtain excellent mechanical properties. While in other temperature ranges,the cooling rate should be decreased appropriately to reduce residual stress. The appropriate average cooling rate is recommendedto be around 13 °C s−1 at the temperature from 340 to 400 °C.

Fabrication of Photopolymer Hierarchical Micronanostructures by Coupling Electrospinning and Photolithography for SERS Substrates

Wen-Yi Zhang,Xin-Ze Xiao,Chao Lv,Jia Zhao,Gong Wang,Xuan Gu,Ran Zhang,Bin-Bin Xu,Dan-Dan Zhang,Ai-Wu Li,Yong-Lai Zhang,Hong-Bo Sun 한국고분자학회 2013 Macromolecular Research Vol.21 No.3

Reported here is the fabrication of photopolymer hierarchical micronanostructures through a combinative process of electrospinning and subsequent photolithography. Electrospun SU-8 (epoxy-based negative photoresist)nanofiber films have been patterned into gratings with periods of 100, 200, 300, and 400 μm, respectively. Deposition of a silver nanolayer on these interlaced nanofiber films would lead to the formation of various plasmonic nanostructures,and therefore, giving rise to abundant surface-enhanced Raman scattering (SERS) “hot spots”. In the detection of Rhodamine 6G (R6G), probing molecule, the resultant SERS substrates show both high sensitivity and good reproducibility. The SERS enhancement factor could reach as high as ~108, indicating high efficiency. The fabrication of patterned, highly efficient SERS substrates may hold a great promise for the integration of SERS substrates in various microdevices such as microfluidic chips.

Wave propagation and vibration of FG pipes conveying hot fluid

Yi-Wen Zhang,Gui-Lin She 국제구조공학회 2022 Steel and Composite Structures, An International J Vol.42 No.3

The existing researches on the dynamics of the fluid-conveying pipes only focus on stability and vibration problems, and there is no literature report on the wave propagation of the fluid-conveying pipes. Therefore, the purpose of this paper is to explore the propagation characteristics of longitudinal and flexural waves in the fluid-conveying pipes. First, it is assumed that the material properties of the fluid-conveying pipes vary based on a power function of the thickness. In addition, it is assumed that the material properties of both the fluid and the pipes are closely depended on temperature. Using the Euler-Bernoulli beam equation and based on the linear theory, the motion equations considering the thermal-mechanical-fluid coupling is derived. Then, the exact expressions of phase velocity and group velocity of longitudinal waves and bending waves in the fluidconveying pipes are obtained by using the eigenvalue method. In addition, we also studied the free vibration frequency characteristics of the fluid-conveying pipes. In the numerical analysis, we successively studied the influence of temperature, functional gradient index and liquid velocity on the wave propagation and vibration problems. It is found that the temperature and functional gradient exponent decrease the phase and group velocities, on the contrary, the liquid flow velocity increases the phase and group velocities. However, for vibration problems, temperature, functional gradient exponent parameter, and fluid velocity all reduce the natural frequency.

Anomalous magnetization jumps in granular Pb superconducting films

Zhang An-Lei,Jiang Wan-Yan,Chen Xing-Hong,Zhang Xiao-Ke,Lu Wen-Lai,Chen Fei,Feng Zhen-Jie,Cao Shi-Xun,Zhang Jin-Cang,Ge Jun-Yi 한국물리학회 2022 Current Applied Physics Vol.35 No.-

In granular superconductors, the grain boundaries are closely related to the vortex dynamics and the macroscopic superconducting properties. In our research, Pb films with different grain sizes were prepared by tuning the substrate temperature. With the grain size decreasing, Pb films are prone to feature the anomalous magnetization jumps in the M − T curves, while in the M − H curves flux avalanche happens. Both phenomena appear in the same region of the H − T phase diagram and thus are considered to have the same origin. The further theoretical analysis shows that with grain size decreasing the pinning mechanism evolves from a mixed δTc and δl pinning to the δl pinning mechanism. The results shed light on the study of pinning mechanism for granular superconductors and is beneficial to the potential application of manipulating vortex pinning by regulation of intrinsic defects.

Possible Epithelial Ovarian Cancer Association with HPV18 or HPV33 Infection

Zhang, Pei-Pei,Zhou, Lei,Cao, Jia-Shi,Li, Yi-Ping,Zeng, Zhi,Sun, Ni,Shen, Li,Zhu, Hao-Yue,Ruan, Yang,Zha, Wen-Ting,Wang, Xin-Yu,Zhang, Ke-Qiang,Zhang, Ran Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.6

The present study was conducted to investigate the prevalence of HPV infection in epithelial ovarian cancer (EOC) in Hunan province. DNA samples were collected from paraffin embedded ovarian tissue from 322 patients with EOC, 99 with ovarian benign tumors and 199 normal persons. The polymerase chain reaction and direct sequencing were used to identify the HPV types in the samples. The relationship between the infection of human papillomavirus (HPV) and the epithelial ovarian carcinoma (EOC) was investigated combined with clinical data. The prevalence of HPV18 and HPV33 in EOC group and benign group was higher than in the normal group. HPV18 and HPV33 may play a role in the development of both EOC and ovarian benign tumor and may participate in the development of EOC with traditional risk factors, family history and abortion, possibly exerting synergistic effects.

Wave propagation in spherical and cylindrical panels reinforced with carbon nanotubes

Yi-Wen Zhang,Hao-Xuan Ding,Gui-Lin She 국제구조공학회 2023 Steel and Composite Structures, An International J Vol.46 No.1

Based on the third-order shear deformation theory, the wave propagations in doubly curved spherical- and cylindrical- panels reinforced by carbon nanotubes (CNTs) are firstly investigated in present work. The coupled equations of wave propagation for the carbon nanotubes reinforced composite (CNTRC) doubly curved panels are established. Then, combined with the harmonic balance method, the eigenvalue technique is adopted to simulate the velocity-wave number curves of the CNTRC doubly curved panels. In the end, numerical results are showed to discuss the effects of the impact of key parameters including the volume fraction, different shell types (including spherical (R1=R2=R) and cylindrical (R1=R, R2=→∞)), wave number as well as modal number on the sensitivity of elastic waves propagating in CNTRC doubly curved shells.

Perioperative Comprehensive Supportive Care Interventions for Chinese Patients with Esophageal Carcinoma: a Prospective Study

Zhang, Xiao-Dan,Zhao, Qing-Yu,Fang, Yi,Chen, Guan-Xuan,Zhang, Hui-Fang,Zhang, Wen-Xiao,Yang, Xiao-Ping Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Objective: To assess the effects of perioperative comprehensive supportive care interventions on outcome of Chinese esophageal cancer patients in a prospective study. Methods: 60 patients with primary esophageal carcinoma were randomized into an intervention group (IG, n=31) and a control group (CG, n=29). The Chinese version of symptom checklist-90 (SCL-90) was adopted to assess their psychological status. The interventions, including health education, psychological support, stress management, coping strategies and behavior training, were carried out in 3 phases (preoperative, postoperative I and postoperative II), and psychological effects were thereafter evaluated accordingly before surgery, and 1 week, 4 weeks and 24 weeks post-surgery. Medical costs were estimated at discharge. Survival of patients was estimated each year post-surgery. General health status and satisfaction-with-hospital were surveyed by a follow-up questionnaire 4 years post-surgery. Results: All the subjects demonstrated higher scores in the preoperative phase than the normal range of Chinese population concerning 7 psychological domains including somatization, obsessive-compulsive, depression, anxiety, hostility, phobic anxiety and paranoid ideation. Although no significant difference was observed between the two groups at admission, the scores of IG, which tended to decrease at a faster rate, were generally lower than those of CG at weeks 1, 4 and 24 post-surgery. The length of hospital stay and medical costs of IG were significantly less than those of CG and satisfaction-with-hospital was better. However, there was no significant difference in 4-year survival or health status between two groups. Conclusions: Appropriate perioperative comprehensive supportive care interventions help to improve the psychological state of Chinese patients with esophageal carcinoma, to reduce health care costs and to promote satisfaction of patients and their families with hospital.

Preferential Induction of CYP1A1 over CYP1B1 in Human Breast Cancer MCF-7 Cells after Exposure to Berberine

Wen, Chun-Jie,Wu, Lan-Xiang,Fu, Li-Juan,Shen, Dong-Ya,Zhang, Xue,Zhang, Yi-Wen,Yu, Jing,Zhou, Hong-Hao Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.1

Estrogens are considered the major breast cancer risk factor, and the carcinogenic potential of estrogens might be attributed to DNA modification caused by derivatives formed during metabolism. $17{\beta}$-estradiol ($E_2$), the main steroidal estrogen present in women, is metabolized via two major pathways: formation of 2-hydroxyestradiol (2-OH $E_2$) and 4-hydroxyestradiol ($4-OH\;E_2$) through the action of cytochrome P450 (CYP) 1A1 and 1B1, respectively. Previous reports suggested that $2-OH\;E_2$ has putative protective effects, while $4-OH\;E_2$ is genotoxic and has potent carcinogenic activity. Thus, the ratio of $2-OH\;E_2/4-OH\;E_2$ is a critical determinant of the toxicity of $E_2$ in mammary cells. In the present study, we investigated the effects of berberine on the expression profile of the estrogen metabolizing enzymes CYP1A1 and CYP1B1 in breast cancer MCF-7 cells. Berberine treatment produced significant induction of both forms at the level of mRNA expression, but with increased doses produced 16~ to 52~fold greater induction of CYP1A1 mRNA over CYP1B1 mRNA. Furthermore, berberine dramatically increased CYP1A1 protein levels but did not influence CYP1B1 protein levels in MCF-7 cells. In conclusion, we present the first report to show that berberine may provide protection against breast cancer by altering the ratio of CYP1A1/CYP1B1, could redirect $E_2$ metabolism in a more protective pathway in breast cancer MCF-7 cells.

Nonlinear harmonic resonances of spinning graphene platelets reinforced metal foams cylindrical shell with initial geometric imperfections in thermal environment

Yi-Wen Zhang,Gui-Lin She 국제구조공학회 2023 Structural Engineering and Mechanics, An Int'l Jou Vol.88 No.5

This paper reveals theoretical research to the nonlinear dynamic response and initial geometric imperfections sensitivity of the spinning graphene platelets reinforced metal foams (GPLRMF) cylindrical shell under different boundary conditions in thermal environment. For the theoretical research, with the framework of von-Karman geometric nonlinearity, the GPLRMF cylindrical shell model which involves Coriolis acceleration and centrifugal acceleration caused by spinning motion is assumed to undergo large deformations. The coupled governing equations of motion are deduced using Euler-Lagrange principle and then solved by a combination of Galerkin’s technique and modified Lindstedt Poincare (MLP) model. Furthermore, the impacts of a set of parameters including spinning velocity, initial geometric imperfections, temperature variation, weight fraction of GPLs, GPLs distribution pattern, porosity distribution pattern, porosity coefficient and external excitation amplitude on the nonlinear harmonic resonances of the spinning GPLRMF cylindrical shells are presented.

Study on economic performances of multi-span suspension bridges part 2: parametric study

Zhang, Li-Wen,Xiao, Ru-Cheng,Sun, Bin,Jiang, Yang,Zhang, Xue-Yi,Zhuang, Dong-Li,Zhou, Yun-Gang,Tu, Xue Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.47 No.2

Economic performances of consecutive multi-span suspension bridges are studied. The material amount and cost estimation formulas of the bridges have been derived in the part 1 of the study. A parametric study is carried out based on the formulas for investigating the different factors' effect on the bridge cost. The factors include the bridge sag, the bridge span, the bridge foundation and the environment condition, etc. Then, an economical layout of the bridges is proposed for different conditions. Lastly, a selection of suspension bridge types is discussed based on the economy of bridges.