Effect of Different Cooling Rates in High Rheological Rate Forming Process on Mechanical Properties of Zr57Cu20Al10Ni8Ag5 Bulk Metallic Glass

Xiao‑Bo Mei,Bao‑Chuan Liu,Wei Jiang,Quan Xu,Qi‑Dong Zhang,Yu‑Bai Ma,Fang‑Qiu Zu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.9

The influence of cooling rates on the mechanical properties of a Zr-based bulk metallic glass prepared with high rheologicalrate forming (HRRF) was investigated and compared with traditional suction cast methods. Amorphous samples of Zr57Cu-20Ni8Al10Ag5 were prepared in copper molds with different sizes in order to obtain different cooling rates for both HRRFand traditional cast methods. These specimens were subjected to compression experiments, including microhardness testing,X-ray diffraction testing and differential scanning calorimetry analysis. The results indicate that the plasticity of the samplesformed by HRRF are higher than that of the as-cast ones at the same cooling rates, while the microhardness manifests theopposite principle. As the cooling rate increases further, the difference in plasticity further increases between two methods,indicating that the plasticity of metallic glasses is more sensitive to cooling rates during the HRRF process. At the core ofthis phenomenon is the fact that HRRF methods can introduce more free volume into glasses than traditional cast methodswith an elevated cooling rate are able to.

A New ent-Kaurane type Diterpenoid Glycoside from Inula japonica Thunb

Jiang Jiang Qin,Jia Xian Zhu,Wei Dong Zhang1,2,Yan Zhu,Jian Jun Fu,Xiao Hua Liu,Hui Zi Jin 대한약학회 2009 Archives of Pharmacal Research Vol.32 No.10

A new ent-kaurane type diterpenoid glycoside, 17-O-β-D-glucopyranosyl-16α-ent-kauran-19-oic acid (1), together with 17-hydroxy-16α-ent-kauran-19-oic acid (2), 16α,17-dihydroxyl-ent-kauran-19-oic acid (3), and 16α-hydroxy-17-acetoxy-ent- kauran-19-oic acid (4) were isolated from the aerial parts of Inula japonica Thunb. The structure of 1 was determined mainly by use of 1D and 2D NMR spectroscopic techniques including HSQC, 1H-1H COSY, HMBC, and NOESY. In addition, 4 exhibited significant inhibitory activity on NO production in LPS-stimulated RAW264.7 cells with IC50 value of 14.3 μg/mL.

Erratum to: The treatment effect of novel hGHRH homodimer to male infertility hamster

Zhang, Xu-Dong,Guo, Xiao-Yuan,Tang, Jing-Xuan,Yue, Lin-Na,Zhang, Juan-Hui,Liu, Tao,Dong, Yu-Xia,Tang, Song-Shan The Korean Society of Pharmacology 2019 The Korean Journal of Physiology & Pharmacology Vol.23 No.1

The treatment effect of novel hGHRH homodimer to male infertility hamster

Zhang, Xu-Dong,Guo, Xiao-Yuan,Tang, Jing-Xuan,Yue, Lin-Na,Zhang, Juan-Hui,Liu, Tao,Dong, Yu-Xia,Tang, Song-Shan The Korean Society of Pharmacology 2018 The Korean Journal of Physiology & Pharmacology Vol.22 No.6

Extra-hypothalamic growth hormone-releasing hormone (GHRH) plays an important role in reproduction. To study the treatment effect of Grin (a novel hGHRH homodimer), the infertility models of 85 male Chinese hamsters were established by intraperitoneally injecting 20 mg/kg of cyclophosphamide once in a week for 5 weeks and the treatment with Grin or human menopausal gonadotropin (hMG) as positive control was evaluated by performing a 3-week mating experiment. 2-8 mg/kg of Grin and 200 U/kg of hMG showed similar effect and different pathological characteristics. Compared to the single cyclophosphamide group (0%), the pregnancy rates (H-, M-, L-Grin 26.7, 30.8, 31.3%, and hMG 31.3%) showed significant difference, but there was no difference between the hMG and Grin groups. The single cyclophosphamide group presented loose tubules with pathologic vacuoles and significant TUNEL positive cells. Grin induced less weight of body or testis, compactly aligned tubules with little intra-lumens, whereas hMG caused more weight of body or testis, enlarging tubules with annular clearance. Grin presented a dose-dependent manner or cell differentiation-dependentincrease in testicular GHRH receptor, and did not impact the levels of blood and testicular GH, testosterone. Grin promotes fertility by proliferating and differentiating primitive cells through up-regulating testicular GHRH receptor without triggering GH secretion, which might solve the etiology of oligoasthenozoospermia.

A Novel Virtual Space Vector Modulation Strategy for the Neutral-Point Potential Comprehensive Balance of Neutral-Point-Clamped Converters

Zhang, Chuan-Jin,Tang, Yi,Han, Dong,Zhang, Hui,Zhang, Xiao,Wang, Ke The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

A novel Virtual Space Vector (VSV) modulation strategy for complete control of potential neutral point (NP) issues is proposed in this paper. The neutral point potential balancing problems of multi-level converters, which include elimination of low frequency oscillations and self-balancing for NP dc unbalance, are investigated first. Then a set of improved virtual space vectors with dynamic adjustment factors are introduced and a multi-objective optimization algorithm which aims to optimize these adjustment factors is presented in this paper. The improved virtual space vectors and the multi-objective optimization algorithm constitute the novel Virtual Space Vector modulation. The proposed novel Virtual Space Vector modulation can simultaneously recover NP dc unbalance and eliminate low frequency oscillations of the neutral point. Experiment results show that the proposed strategy has excellent performance, and that both of the neutral point potential issues can be solved.

Research on steady characteristics of human-robot system for preventing elderly falls during walking

Xiao Dong Zhang,Xiaoqi Mu,Liangliang Li,Ahmad Bala Alhassan,Khaled Kadry Hamza 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.9

Due to the ever-increasing demand of caregivers and the high cost of nursing the elderly, researchers have been developing the elderly assistant robots (EARs) for assisting the elderly. To improve the safety of the elderly during walking, the steady characteristics of the EAR are discussed for preventing elderly falls during walking in this paper. Initially, the walking elderly was modeled as an inverted pendulum, and the steadiness region of the human and the general elderly fall conditions were obtained. The dynamics of the human-robot system were derived for preventing the general elderly falls. Also, the steadiness of the human and the robot were analyzed, respectively. Finally, experiments were conducted to verify the effectiveness of the models. The results demonstrated that the system met the requirements of steadiness, and hence, the designed robot could prevent elderly fall during walking. Thus, this study provides a theoretical basis for the effective control and the practical application of the EARs.

Patients with Spontaneously Ruptured Hepatocellular Carcinoma Benefit from Staged Surgical Resection after Successful Transarterial Embolization

Zhang, Dong-Zhi,Zhang, Ke,Wang, Xiao-Peng,Cai, Hui Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.1

Background: Surgical resection of spontaneously ruptured hepatocellular carcinoma (HCC) after successful transarterial embolization (TAE) remains controversial. The aim of this study was to investigate its efficacy in a series of cases. Materials and Methods: We retrospectively examined ruptured HCC cases from Jan 2000 to Dec 2008; all of these 126 cases received TAE as the initial therapy. Subsequently, 74 cases received staged surgical resection, and the remaining 52 cases underwent repeated TACE. The baseline demographic data, tumor characteristics, and long term survival were recorded and compared. Results: The demographic and baseline characteristics were comparable between the hepatic resection and TACE groups; furthermore, no significant difference in the tumor characteristics was detected between the two groups. The differences in in-hospital, 30-day and 90-day mortality between the two groups were not significant (P>0.05). However, the 1-, 3-, and 5-year overall survival rates were 85.1%, 63.5%, and 37.8%, respectively, in the hepatic resection group, which were significantly higher than those in the TACE group (69.2%, 46.2%, and 17.3%, respectively, P=0.004). Univariate and multivariate analyses indicated that these patients benefitted from hepatic resection compared with TACE with respect to long-term outcomes. Conclusions: Staged hepatic resection after TAE is an effective treatment that results in superior long-term survival to repeated TACE.

Distributed Consensus Control for Automatic Gauge Control of Hot Strip Mills

Xiao-Dong Zhang,Shao-Shu Gao,Wei-Xi Gao,Xu-Ying Wang,Wei Zhang 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.5

In this study, the distributed control strategy is proposed for the automatic gauge control(AGC) system, which is a typical multi-agent system. The distributed control protocol is developed with the subspace identification method using the measurements of the local agent and its neighbors directly,without any knowledge of the AGC system dynamics. The stability analysis of the multi-agent system with the proposed control protocol is given. In addition, the consensus control protocol with communication time delay is investigated. Finally, simulation results are carried out to verify the feasibility and effectiveness of the proposed control strategy.

Pattern Recognition of Human Grasping Operations Based on EEG

Xiao Dong Zhang,Hyouk Ryeol Choi 대한전기학회 2006 International Journal of Control, Automation, and Vol.4 No.5

The pattern recognition of the complicated grasping operation based on electroencephalography (simply named as EEG) is very helpful on realtime control of the robotic hand. In the paper, a new spectral feature analysis method based on Band Pass Filter (simply named as BPF) and Power Spectral Analysis (simply named as PSA) is presented for discriminating the complicated grasping operations. By analyzing the spectral features of grasping operations with the use of the two-channel EEG measurement system and the pattern recognition of the BP neural network, the degree of recognition by the traditional spectral feature method based on FFT and the new spectral features method based on BPF and PSA could be compared. The results show that the proposed method provides highly improved performance than the traditional one because the new method has two obvious advantages such as high recognition capability and the fast learning speed.

Catalytic topological insulator Bi₂Se₃ nanoparticles for <i>in</i> <i>vivo</i> protection against ionizing radiation

Zhang, Xiao-Dong,Jing, Yaqi,Song, Shasha,Yang, Jiang,Wang, Jun-Ying,Xue, Xuhui,Min, Yuho,Park, Gyeongbae,Shen, Xiu,Sun, Yuan-Ming,Jeong, Unyong Elsevier 2017 Nanomedicine Vol.13 No.5

<P><B>Abstract</B></P> <P>Bi<SUB>2</SUB>Se<SUB>3</SUB> nanoparticles (NPs) have attracted wide interests in biological and medical applications. Layer-like Bi<SUB>2</SUB>Se<SUB>3</SUB> with high active surface area is promising for free radical scavenging. Here, we extended the medical applications of Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs further to <I>in vivo</I> protection against ionizing radiation based on their superior antioxidant activities and electrocatalytic properties. It was found that Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs can significantly increase the surviving fraction of mice after exposure of high-energy radiation of gamma ray. Additionally, the Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs can help to recover radiation-lowered red blood cell counts, white blood cell counts and platelet levels. Further investigations revealed that Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs behaved as functional free radical scavengers and significantly decreased the level of methylenedioxyamphetamine. <I>In vivo</I> toxicity studies showed that Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs did not cause significant side effects in panels of blood chemistry, clinical biochemistry and pathology.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs can significantly increase the surviving fraction of mice up to 70% after Gamma radiation. </LI> <LI> Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs can help to recover radiation-lowered red blood cell counts, white blood cell counts and platelet levels. </LI> <LI> Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs behaved as functional free radical scavengers and significantly decreased the level of methylenedioxyamphetamine. </LI> </UL> </P> <P><B>Graphical Abstract</B></P> <P>Layer-like Bi<SUB>2</SUB>Se<SUB>3</SUB> with high active surface area can protect mice against ionizing radiation based on their superior antioxidant activities and electrocatalytic properties. Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs can significantly increase the surviving fraction of mice up to 70% after exposure of high-energy radiation of gamma ray. Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs behaved as functional free radical scavengers and significantly decreased the level of methylenedioxyamphetamine. <I>In vivo</I> toxicity studies showed that Bi<SUB>2</SUB>Se<SUB>3</SUB> NPs did not cause significant side effects in panels of blood chemistry, clinical biochemistry and pathology.</P> <P>[DISPLAY OMISSION]</P>