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.

충북 지방자치단체의 지방재정력 격차분석

장의, 박종섭 忠北大學校 農業科學硏究所 2014 農業科學硏究 Vol.30 No.2

South Korea has enforced local autonomy system since 1995. However, local government have still difficulty in accomplishing autonomy due to the centralized power structure and taxation source. In each local government, measures for inter-regional balanced development have been promoted on an ongoing basis. Moreover, the vertical imbalance between the central and local-finance, even disparity, and horizontal imbalances among regions of the municipalities gets worse and worse. The purpose of this study is to analyze the categories of revenue and expenditure centred on local governments in Chungbuk, presenting the causes of local. financial gap and measures to mitigate them. Meanwhile, factors of disparity in financial power are analyzed between the city and county. Results of the analysis are as follows: the level of income per capita in rural areas is higher than in urban areas. The level of expenditure per capita in rural areas is also higher than in urban areas. To mitigate the disparity of the local financial strength, it is necessary to take advantage of the improvement of policy alternatives.

Clinical Efficacy and Prognosis Factors for Advanced Hepatoblastoma in Children: A 6-year Retrospective Study

Zhang, Yi,Zhang, Wei-Ling,Huang, Dong-Sheng,Hong, Liang,Wang, Yi-Zhuo,Zhu, Xia,Hu, Hui-Min,Zhang, Pin-Wei,Yi, You,Han, Tao Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.8

Objective: This study aimed to investigate the effect of multimodality treatment of advanced paediatric hepatoblastoma (HB) and the factors affecting prognosis. Methods: A total of 35 children underwent multimodality treatments consisting of chemotherapy, surgery, interventional therapy, and autologous peripheral blood stem cell transplantation. The patients were followed up every month. Results: Serum AFP levels in 33 out of 35 patients in this study were significantly increased (P = 0.0002). According to the statistical scatter plot, the values of serum AFP on the 25th, 50th, and 75th percentages were 1,210, 1,210 and 28,318 ng/dl, respectively. Of the 35 cases, 21 were stage IV. 18 cases were treated with systemic chemotherapy before surgery, and 3 cases with locally interventional chemotherapy before surgery. Statistical analysis showed that the preferred interventional treatment affected prognosis, and that there was a statistically significant difference (P = 0.024). Some 33 patients completed the follow-up, of which 17 were in complete remission (CR), 5 were in partial remission (PR), 1 became disease progressive (DP), and 10 died. The remission and overall survival rates were 66.7% (22/33) and 69.7% (23/33), respectively. Patients with the mixed HB phenotypes had worse prognoses than the epithelial phenotype (P < 0.001), and patients in stage IV had a lower survival rate than those in stage III (P < 0.001). Conclusion: Multimodality treatment can effectively improve remission rate and prolong the survival of children with advanced HB. In addition, alpha-fetoprotein (AFP), a tumor marker of liver malignant tumors, HB pathological classification, and staging are highly useful in predicting prognosis.

Enhancing Cross-Cultural Adaptation Skills of International Chinese Language Teachers

Zhang Lin(Lin Zhang),Sun Yi(Yi Sun) 아시아사회과학학회 2023 Jornal of Asia Social Science Vol.10 No.2

Since 2004, China National Office for Teaching Chinese as a Foreign Language began dispatching international Chinese language teachers to countries in need around the world, the teachers have made important contributions to international Chinese language education and cultural communication. International Chinese language teachers are bound to face various discomfort and difficulties when working and living in a cultural environment different from their own, which affects both their teaching and personal life. This paper attempts to analyze the internal and external factors that affect the teachers’ cross-cultural adaptability, as well as the deficiencies in pre-job training for international Chinese language teachers, to find the existing problems and make suggestions to solve them.

Risk Factors for Cervical Cancer in Rural Areas of Wuhan China: a Matched Case-control Study

Zhang, Bin,Zhou, Ai-Fen,Zhu, Chang-Cai,Zhang, Ling,Xiang, Bing,Chen, Zhong,Hu, Rong-Hua,Zhang, Ya-Qi,Qiu, Lin,Zhang, Yi-Ming,Xiong, Chao-Du,Du, Yu-Kai,Shi, Yu-Qin Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Cervical cancer is a serious public health problem in developing countries. We investigated possible risk factors for cervical cancer in rural areas of Wuhan China using a matched case-control study with 33 women diagnosed with cervical cancer and 132 healthy women selected from the same area as matched controls. A questionnaire, which included questions about general demography conditions, environmental and genetic factors, the first sexual intercourse, first marriage age, age at first pregnancy, pregnancy first child's age, female personal health history, social psychological factors, dietary habits, smoking and alcohol status and other living habits was presented to all participants. At the same time, HPV infection of every participant was examined in laboratory testing. Results showed HPV infection (P<0.000, OR=23.4) and pregnancy first child's age (P<0.000, OR=13.1) to be risk factors for cervical cancer. Menopause (P=0.003, OR=0.073) was a protective factor against cervical cancer. However, there was no indication of associations of environmental (drinking water, insecticide, disinfectant) genetic (cancer family history), or life-style factors (smoking status, alcohol status, physical training, sleep quality), including dietary habits (intake of fruit and vegetable, meat, fried food, bean products and pickled food) or social psychological factors with cervical cancer. The results suggest that the risk of cervical cancer in Chinese rural women may be associated with HPV infection, menopause and the pregnancy first child's age.

A 32.2 GHz Full Adder Designed with TLE Method in a InP DHBT Technology

Yi Zhang,Xiaopeng Li,Youtao Zhang,Yufeng Guo,Ying Zhang,Hao Gao 대한전자공학회 2021 Journal of semiconductor technology and science Vol.21 No.6

Ultra-high-speed full adder is the bottleneck in a tens of GHz Direct digital synthesizer (DDS). In this paper, a 32.2 GHz, 1bit full adder in a 0.7 μm InP double hetero-junction bipolar transistor (DHBT) technology is presented. In such a high-speed circuit, signal integrity is a crucial issue. Therefore, a transmission line equivalent (TLE) method is proposed. With the TLE method, the design of the full adder could be simplified with good accuracy. The synchronous latch is combined with adding operation to improve the calculation speed. A single-level parallel-gated circuit is designed using majority decision algorithm to reduce power consumption. Measurement results show that the maximum clock frequency of the full adder is 32.2-GHz, and the overall power consumption is 350 mW. The full adder is successfully adopted in a 17 GHz, 8 bit DDS which can synthesize sin-wave outputs from 66.41 MHz to 8.5 GHz in 66.41 MHz steps with an average Spurious-Free Dynamic Range (SFDR) of -18.1 dBc.

Supervisory Optimization of the MGT-CCHP System Using Model Predictive Control

Yi Zhang,Fan Zhang,Xiao Wu,Junli Zhang,Li Sun,Jiong Shen 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10

This paper proposes a supervisory optimal control structure for the micro-gas-turbine based combined cooling heating and power (MGT-CCHP) system. In the upper layer of the structure, a dynamic optimal reference governor is developed to calculate the optimal operating points according to the given economic performance indexes, and in the lower layer of the structure, model predictive control is utilized to track the given operating points, so that a dynamic optimality can be achieved under the input-output constraints during the optimization. Moreover, a disturbance term is introduced in the model to lump the effect of unmeasured disturbances and plant behavior variations, thus, their influences on the supervisory optimization can be removed. The advantages and effectiveness of the proposed method are demonstrated through the simulations on an 80kW MGT-CCHP simulator.

Long term structural health monitoring for old deteriorated bridges: a copula-ARMA approach

Yi Zhang,Chul-Woo Kim,Lian Zhang,Yongtao Bai,Hao Yang,Xiangyang Xu,Zhenhao Zhang 국제구조공학회 2020 Smart Structures and Systems, An International Jou Vol.25 No.3

Long term structural health monitoring has gained wide attention among civil engineers in recent years due to the scale and severity of infrastructure deterioration. Establishing effective damage indicators and proposing enhanced monitoring methods are of great interests to the engineering practices. In the case of bridge health monitoring, long term structural vibration measurement has been acknowledged to be quite useful and utilized in the planning of maintenance works. Previous researches are majorly concentrated on linear time series models for the measurement, whereas nonlinear dependences among the measurement are not carefully considered. In this paper, a new bridge health monitoring method is proposed based on the use of long term vibration measurement. A combination of the fundamental ARMA model and copula theory is investigated for the first time in detecting bridge structural damages. The concept is applied to a real engineering practice in Japan. The efficiency and accuracy of the copula based damage indicator is analyzed and compared in different window sizes. The performance of the copula based indicator is discussed based on the damage detection rate between the intact structural condition and the damaged structural condition.

A 2 GS/s, 6-bit DAC for UWB Applications In 0.18 ㎛ CMOS Technology

Yi Zhang,Zhonghua Liu,Changchun Zhang,Yufeng Guo,Ying Zhang,Xiaopeng Li,Youtao Zhang,Hao Gao 대한전자공학회 2019 Journal of semiconductor technology and science Vol.19 No.6

To satisfy higher and higher transmission rate and broadband requirement of modern communication, high-speed, low-resolution Digital-to-Analog Converters (DACs) becomes the key element. In this paper, the design of a 2 GS/s, 6 bit DAC without calibration for Ultra-wideband (UWB) applications, is presented. The DAC is based on current steering architecture and is segmented with 4 bit unary and 2 bit binary. To realize larger linear range and fast switching, the source degeneration switch is designed instead of the traditional differential switch. The DAC is designed and taped-out in SMIC 0.18 ㎜ CMOS technology and the area is 975 ㎛´ 775 ㎛. The wafer bonding measurement results shows that the DNL is 0.11 LSB, INL is 0.25 LSB. Under a clock frequency of 2 ㎓, the DAC can achieve a SFDR of 51 ㏈ for input signal of 6㎒, and a SFDR of 32.4 ㏈ for Nyquist input while the power consumption is 79 ㎽.

RhoGDI2 induced malignant phenotypes of pancreatic cancer cells via regulating Snail expression

Yi Bin,Hu You,Zhu Dongming,Yao Jun,Zhou Jian,Zhang Yi,He Zhilong,Zhang Lifeng,Zhang Zixiang,Yang Jian,Tang Yuchen,Huang Yujie,Li Dechun,Liu Qiuhua 한국유전학회 2022 Genes & Genomics Vol.44 No.5

Background: Rho GDP dissociation inhibitor 2 (RhoGDI2) has been shown to contribute to the aggressive phenotypes of human cancers, such as tumor metastasis and chemoresistance. Objective: This study aimed to assess the effects of RhoGDI2 on tumor progression and chemoresistance in pancreatic cancer cells. Methods: The expression of RhoGDI2 in pancreatic cancer cells was detected by Western blot analysis. Gain-of-function and loss-of-function approaches were done to examine the malignant phenotypes of the RhoGDI2-expressing or RhoGDI2-depleting cells. The correlation between RhoGDI2 and Snail was also analyzed. Results: Differential expression of RhoGDI2 protein in pancreatic cancer cell lines was identified. Gain-of-function and loss-of-function experiments showed that RhoGDI2 induced the malignant phenotypes of pancreatic cancer cells, including proliferation, migration, invasion, and gemcitabine (GEM) chemoresistance. The upregulation of RhoGDI2 stimulated the expression of Snail, resulting in the altered expression of epithelial marker E-cadherin and mesenchymal marker Vimentin, which were characteristics of the tumorigenic activity of epithelial-mesenchymal transition. The expression of RhoGDI2 and Snail was upregulated in clinical tumor samples, and higher expression of RhoGDI2 or Snail was significantly associated with poor patient survival in pancreatic ductal adenocarcinoma (PDAC). Conclusion: The findings indicated that RhoGDI2 promoted GEM resistance and tumor progression in pancreatic cancer and that RhoGDI2 might be a potential therapeutic target in patients with PDAC.