Hot Deformation Behavior and Recrystallization Mechanism in an As-Cast CoNi-Based Superalloy

Yong Guan,Yongchang Liu,Zongqing Ma,Huijun Li,Hongyao Yu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

The hot deformation behavior of as-cast CoNi-based superalloy was investigated by means of hot compression tests. Thecorresponding microstructure evolution after hot deformation was examined by optical microscope, as well as the TEMtechnique. The constitutive equation and processing map as a function of deformation temperature and strain rate were developed. Results show that the efficiency peak of the processing map is 0.38 at the temperature of 1130 °C and the strain rate of0.01 s−1. The discontinuous dynamic recrystallization (DDRX) related to the strain-induced grain boundary migration (SIBM)is the dominant recrystallization mechanism during hot working. Meanwhile, the DRX also occurs by forming sub-grainsaround MC carbides and shear band. In addition, the existence of fine γ′ precipitates are found to retard the recrystallization.

In-situ photocrosslinked hydroxide conductive membranes based on photosensitive poly(arylene ether sulfone) block copolymers for anion exchange membrane fuel cells

He, Rui,Wen, Pushan,Zhang, Hai-Ning,Guan, Shumeng,Xie, Guangyong,Li, Li-Zhong,Lee, Myong-Hoon,Li, Xiang-Dan Elsevier 2018 Journal of membrane science Vol.556 No.-

<P><B>Abstract</B></P> <P>A series of photocrosslinkable multi-block poly(arylene ether sulfone) copolymers containing various block lengths of hydrophilic segments were synthesized. For comparison, a series of random poly(arylene ether) copolymers were also synthesized. The anion exchange membranes(AEMs) were fabricated and in-situ photocrosslinking was carried out by UV irradiation in a swollen state. The microphase-separated morphologies of the multi-block membranes were characterized by SAXS and TEM experiments, and the membrane properties were investigated by measuring ion exchange capacity (IEC), water uptake, water swelling ratio, ionic conductivity, methanol permeability and alkaline stability. IECs and water uptakes of the crosslinked multi-block membranes were in the range of 1.11–1.42 meq g<SUP>−1</SUP> and 14.36–31.01% at 20 °C, respectively. The hydroxide conductivity was in the range of 11.38–25.00 mS cm<SUP>−1</SUP> at 20 °C, and showed a maximum value of 178.77 mS cm<SUP>−1</SUP> at 100 °C. The multi-block membranes exhibited low methanol permeability (2.75 × 10<SUP>−7</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>) at room temperature, which is one order of magnitude lower than that of Nafion® 117 (23.8 × 10<SUP>−7</SUP> cm<SUP>2</SUP> s<SUP>−1</SUP>). The crosslinked membranes showed excellent dimensional stability and alkaline stability with only a slight decrease in ionic conductivity. All the multi-block membranes showed superior properties compared to their corresponding random copolymers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Multi-block poly(arylene ether sulfone) copolymers were synthesized for AEMs. </LI> <LI> <I>In-situ</I> photo-crosslinking was carried out by UV irradiation in hydrated states. </LI> <LI> The block copolymers exhibited hydrophilic/hydrophobic phase separated morphology. </LI> <LI> The block copolymers showed superior properties compare to the random copolymers. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Cholesteryl naphthalimide-based gelators: Their applications in the multiply visual sensing of CO₂ based on an anion-induced strategy

Zhang, Xin,Li, Haimiao,Mu, Huifang,Liu, Yifan,Guan, Yanan,Yoon, Juyoung,Yu, Haitao Elsevier 2017 Dyes and pigments Vol.147 No.-

<P><B>Abstract</B></P> <P>Several cholesteryl naphthalimide-derived compounds have been sythesized and developed as CO<SUB>2</SUB> sensors. The derivatives, incorporating ether chains, were found to be capable of gelating various organic solvents, due to the modulation of the hydrophilicity/hydrophobility properties of them. The resulting organogels were well characterized by field emission scanning electron microscopy (FE-SEM), FT-IR spectroscopy, concentration- and temperature-dependent <SUP>1</SUP>H NMR spectra, and powder X-ray diffraction (PXRD). These gelators can be applied as fluorescent sensors for CO<SUB>2</SUB> in DMSO solutions via the anion-triggered strategy. Furthermore, the resulting organogelation systems in DMSO could also provide visual sensing means for CO<SUB>2</SUB> via the reversible solution-to-gel transition. Particularly, the re-gelation of DMSO induced by CO<SUB>2</SUB> bubbling could be directly observed without the aid of the heating-and-cooling operation. And the reversible sensing process could be repeated several times with the excellent chemical stability of the gelation system after the repeated stimuli of fluoride anion, CO<SUB>2</SUB> and N<SUB>2</SUB> with heating. These investigations indicate the developed organogelators own the applicable potential in the CO<SUB>2</SUB> detection.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Two new cholesteryl naphthalimide-based organogelators are developed for CO<SUB>2</SUB> sensing based on an anion-induced strategy. </LI> <LI> Sensors <B>1b</B> and <B>1c</B> exhibited optically ratiometric detection effects for CO<SUB>2</SUB> in solution with relatively low detection limits. </LI> <LI> Gelator <B>1c</B> can provide a visual sensing means for CO<SUB>2</SUB> directly via solution-gel transition. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Excellent microwave absorption of FeCo/ZnO composites with defects in ZnO for regulating the impedance matching

Bao, Xiukun,Wang, Xiaolei,Zhou, Xinao,Shi, Guimei,Xu, Ge,Yu, Jin,Guan, Yinyan,Zhang, Yajing,Li, Da,Choi, Chuijin Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.769 No.-

<P><B>Abstract</B></P> <P>FeCo/ZnO composites have been successfully prepared through liquid-phase reduction process for the formation of FeCo polyhedrons and sequentially thermal decomposition of colloidal mixture of FeCo and Zn(Ac)<SUB>2</SUB>·2H<SUB>2</SUB>O under nitrogen atmospheres. ZnO nanoparticles are homogeneously deposited on the surface of FeCo polyhedrons and the level of oxygen-vacancy defects in ZnO can be elevated with the increase of ZnO content. By comparison with FeCo polyhedrons, FeCo/ZnO composites exhibit excellent microwave absorption. The optimal RL value can reach −34.8 dB at 14.8 GHz and effective bandwidth (RL < −10 dB) is 5.1 GHz in the frequency range of 12.4–17.5 GHz with a matching thickness of 1.5 mm. The integrated bandwidth with RL < −10 dB can reach 14.1 GHz covering 3.4–17.5 GHz. Theory analysis demonstrates the interfacial polarization, dipole polarization and high conductivity due to oxygen-vacancy defects in FeCo/ZnO composites contribute to enhancement of dielectric loss capacity, which is more favorable for impedance matching.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The preferable impedance matching of FeCo/ZnO composites can be achieved by regulating the ZnO content. </LI> <LI> The optimal reflection loss (RL) can reach −34.8 dB with a matching thickness of 1.5 mm. </LI> <LI> The effective bandwidth with RL < −10 dB achieve 14.1 GHz covering 3.4–17.5 GHz with integrated thickness of 1.5–5 mm. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Morphological Factors and Cardiac Doses in Whole Breast Radiation for Left-sided Breast Cancer

Guan, Hui,Dong, Yuan-Li,Ding, Li-Jie,Zhang, Zi-Cheng,Huang, Wei,Liu, Cheng-Xin,Fu, Cheng-Rui,Zhu, Jian,Li, Hong-Sheng,Li, Miao-Miao,Li, Bao-Sheng Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.7

Background: To investigate the impact of the breast size, shape, maximum heart depth (MDH), and chest wall hypotenuse (the distance connecting middle point of the sternum and the length of lung draw on the selected transverse CT slice) on the volumetric dose to heart with whole breast irradiation (WBI) of left-sided breast cancer patients. Materials and Methods: Fifty-three patients with left-sided breast cancer undergoing adjuvant intensity-modulated radiotherapy (IMRT) were enrolled in the study. The primary breast size and shape, MHD and DCWH (chest wall hypotenuse) were contoured on radiotherapy (RT) planning CT slices. The dose data of hearts were obtained from the dose-volume histograms (DVHs). Data were analyzed by one-way analysis of variance (ANOVA), Student's t-test and linear regression analysis. Results: Breast size was independent of heart dose, whereas breast shape, MHD and DCWH were correlated with heart dose. The shapes of breasts were divided into four types, as the flap type, hemisphere type, cone type and pendulous type with heart mean dose being $491.8{\pm}234.6cGy$, $752.7{\pm}219.0cGy$, $620.2{\pm}275.7cGy$, and $666.1{\pm}238.0cGy$, respectively. The flap type of breasts shows a strong statistically reduction in heart dose, compared to others (p=0.008 for V30 of heart). DCWH and MHD were found to be the most important parameters correlating with heart dose in WBI. Conclusions: More attention should be paid to the heart dose of non-flap type patients. The MHD was found to be the most important parameter to correlate with heart dose in tangential WBI, closely followed by the DCWH, which could help radiation oncologists and physicsts evaluate heart dose and design RT plan in advance.

Bimodal Phenomenon of the Stress–Strain Curve During Hot Compression of LA43M Mg–Li Alloy

Yi Li,Yanjin Guan,Hu Chen,Jiqiang Zhai,Jun Lin,Liang Chen 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

In this study, the samples of LA43M Mg–Li alloy were compressed to the true strains of 0.12, 0.16, 0.36 and 0.60 under300 °C and the strain rate of 0.1 s−1. Under this condition, the stress–strain curves present a special bimodal phenomenon atthe early deformation stage, which is caused by twinning and dynamic recrystallization. In the process of hot compression,extension twins generated first. Twinning accommodated strain and the glide of twinning dislocations dissipated local strainenergy, resulting in the first local stress drop. Then extension twins coarsened and devoured all the matrix, leading to thechange of grain orientation. Subsequently, dislocations accumulated at the grain boundaries and resulted in the increase instress. With further strain, dynamic recrystallization occurred, discontinuous dynamic recrystallization is the main dynamicrecrystallization mechanism. The generation of dynamic recrystallization resulted in the strain softening and leaded tothe second local stress drop. Twinning retards the occurrence dynamic recrystallization and has a crucial influence on themicrostructure development during the hot compression of LA43M.

Optimized Medium Improves Expression and Secretion of Extremely Thermostable Bacterial Xylanase, XynB, in Kluyveromyces Lactis

( Yin Tie ),( Li Li Miao ),( Fei Fei Guan ),( Gui Li Wang ),( Qing Peng ),( Bing Xue Li ),( Guo Hua Guan ),( Ying Li ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.11

An extremely thermostable xylanase gene, xynB, from the hyperthermophilic bacterium Thermotoga maritima MSB8 was successful expressed in Kluyveromyces lactis. The response surface methodology (RSM) was also applied to optimize the medium components for the production of XynB secreted by the recombinant K. lactis. The secretion level (102 mg/l) and enzyme activity (49 U/ml) of XynB in the optimized medium (yeast extract, lactose, and urea; YLU) were much higher than those (56 mg/l, 16 U/ml) in the original medium (yeast extract, lactose, and peptone; YLP). The secretory efficiency of mature XynB was also improved when using the YLU medium. When the mRNA levels of 13 characterized secretion-related genes in the K. lactis cultured in YLP and YLU were detected using a semiquantitative RT-PCR method, the unfolded protein response (UPR)-related genes, including ero1, hac1, and kar2, were found to be up-regulated in the K. lactis cultured in YLU. Therefore, the nutrient ingredients, especially the nitrogen source, were shown to have a significant influence on the XynB secretory efficiency of the host K. lactis.

Value of contrast-enhanced ultrasonography in microwave ablation treatment of symptomatic focal uterine adenomyosis

Xiao-Long Li,Jia-Xin Li,Song-Yuan Yu,Pei-Li Fan,Yun-Jie Jin,Er-Jiao Xu,Sai-Nan Guan,Er-Ya Deng,Qiu-Yan Li,Zheng-Biao Ji,Jiu-Ling Qi,Hui-Xiong Xu,China Alliance of Multi-Center Clinical Study for Ultra 대한초음파의학회 2024 ULTRASONOGRAPHY Vol.43 No.1

Purpose: This study evaluated the value of contrast-enhanced ultrasonography (CEUS) in the ultrasound-guided microwave ablation (MWA) treatment of symptomatic focal uterine adenomyosis.Methods: This retrospective study was conducted between March 2020 and January 2023, enrolling 52 patients with symptomatic focal uterine adenomyosis who had undergone MWA. All patients were examined with CEUS before and after MWA. The non-perfused volume (NPV) was compared between CEUS and dynamic contrast-enhanced magnetic resonance imaging (DCEMRI) following ablation. Therapeutic efficacy and safety were evaluated at 3-, 6-, and 12-month follow-ups. Additionally, this study explored the correlations between pre-treatment CEUS features and a volume reduction ratio indicating sufficient ablation, defined as 50% or more at the 3-month follow-up.Results: No significant differences in NPV were noted between CEUS and DCE-MRI immediately after MWA and during follow-up (all P>0.05). At the 3-month follow-up, the median VRRs for the uterus and adenomyosis were 33.2% and 63.9%, respectively. Sufficient ablation was achieved in 69.2% (36/52) of adenomyosis cases, while partial ablation was observed in the remaining 30.8% (16/52). The identification of non-enhancing areas on pre-treatment CEUS was associated with sufficient ablation (P=0.016). At the 12-month follow-up, significant decreases were observed in both the uterine and adenomyosis volumes (all P<0.001). Dysmenorrhea and menorrhagia were significantly alleviated at 12 months, and no major complications were encountered.Conclusion: CEUS can be used to evaluate the ablation zone of focal adenomyosis that has been treated with MWA, similarly to DCE-MRI. The identification of non-enhancing areas on pretreatment CEUS indicates satisfactory treatment outcomes. Purpose: This study evaluated the value of contrast-enhanced ultrasonography (CEUS) in the ultrasound-guided microwave ablation (MWA) treatment of symptomatic focal uterine adenomyosis. Methods: This retrospective study was conducted between March 2020 and January 2023, enrolling 52 patients with symptomatic focal uterine adenomyosis who had undergone MWA. All patients were examined with CEUS before and after MWA. The non-perfused volume (NPV) was compared between CEUS and dynamic contrast-enhanced magnetic resonance imaging (DCE- MRI) following ablation. Therapeutic efficacy and safety were evaluated at 3-, 6-, and 12-month follow-ups. Additionally, this study explored the correlations between pre-treatment CEUS features and a volume reduction ratio indicating sufficient ablation, defined as 50% or more at the 3-month follow-up. Results: No significant differences in NPV were noted between CEUS and DCE-MRI immediately after MWA and during follow-up (all P>0.05). At the 3-month follow-up, the median VRRs for the uterus and adenomyosis were 33.2% and 63.9%, respectively. Sufficient ablation was achieved in 69.2% (36/52) of adenomyosis cases, while partial ablation was observed in the remaining 30.8% (16/52). The identification of non-enhancing areas on pre-treatment CEUS was associated with sufficient ablation (P=0.016). At the 12-month follow-up, significant decreases were observed in both the uterine and adenomyosis volumes (all P<0.001). Dysmenorrhea and menorrhagia were significantly alleviated at 12 months, and no major complications were encountered. Conclusion: CEUS can be used to evaluate the ablation zone of focal adenomyosis that has been treated with MWA, similarly to DCE-MRI. The identification of non-enhancing areas on pre- treatment CEUS indicates satisfactory treatment outcomes.

Effects of Aqueous Extract of Schizandra Chinensis Fruit on Cadmium-Induced Change of Monoamine Neurotransmitters in Rats

Zhao, Zheng Lin,Zhao, Guang Wen,Li, Li,Li, Meng Quan,Guan, Li Xin,Yang, Xu Dong,Li, Hou Zhong,Lin, Feng,Lee, Jong-Rok,Zhao, Rong Jie Korean Society of ToxicologyKorea Environmental Mu 2009 Toxicological Research Vol.26 No.1

The effects of aqueous extract of Schizandra Chinensis Fruit (AESC) on cadmium-induced changes of monoamine neurotransmitters in the different brain regions of adult rats were investigated. Male rats were received intraperitoneal (i.p.) administration of CdCl2 (0.6 mg/kg/d) for 21 days and sacrificed 7 days after the last administration. Concentrations of norepinephrine (NE), dopamine (DA) in striatum and serotonin (5-HT), 5-hydroxyindole acetic acid (5-HIAA) in cortex were measured by HPLC. There were significant decreases of NE, DA, 5-HT and 5-HIAA in Cd intoxicated rats (P < 0.05), while pretreatment with AESC (20 mg/kg/d or 60 mg/kg/d, p.o., 30 min before $CdCl_2$) greatly inhibited the decrease of monoamine transmitters, respectively (P < 0.05). Also, AESC significantly increased the reduction of glutathione contents and superoxide dismutase activities in cortex induced by $CdCl_2$. These results suggest that AESC ameliorates Cd-induced depletion of monoamine neurotransmitters in brain through its antioxidant activity.

Effects of Aqueous Extract of Schizandra Chinensis Fruit on Cadmium-Induced Change of Monoamine Neurotransmitters in Rats

Zheng Lin Zhao,Guang Wen Zhao,Li Li,Meng Quan Li,Li Xin Guan,Xu Dong Yang,Hou Zhong Li,Feng Lin,Jong Rok Lee,Rong Jie Zhao 한국독성학회 2009 Toxicological Research Vol.25 No.1

The effects of aqueous extract of Schizandra Chinensis Fruit (AESC) on cadmium-induced changes of monoamine neurotransmitters in the different brain regions of adult rats were investigated. Male rats were received intraperitoneal (i.p.) administration of CdCl₂ (0.6 ㎎/㎏/d) for 21 days and sacrificed 7 days after the last administration. Concentrations of norepinephrine (NE), dopamine (DA) in striatum and serotonin (5-HT), 5-hydroxyindole acetic acid (5-HIAA) in cortex were measured by HPLC. There were significant decreases of NE, DA, 5-HT and 5-HIAA in Cd intoxicated rats (P < 0.05), while pretreatment with AESC (20 ㎎/㎏/d or 60 mg/kg/d, p.o., 30 min before CdCl₂) greatly inhibited the decrease of monoamine transmitters, respectively (P < 0.05). Also, AESC significantly increased the reduction of glutathione contents and superoxide dismutase activities in cortex induced by CdCl₂. These results suggest that AESC ameliorates Cd-induced depletion of monoamine neurotransmitters in brain through its antioxidant activity.