Dynamic and Damage Characteristics of Mortar Composite under Impact Load

Qing Li,Tong-de Zhao,Chen Huang,Bing-bing Yu,Zheng-Hua Gao,Kai Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.3

In the process of underground construction, it is common to spray concrete on the working surface, which will form a concrete-rock composite structure, to achieve the expected reinforcement effect. Compared with pure concrete or rock structures, composite structures have different mechanical properties, energy evolution and damage characteristics. Understanding the dynamic mechanics and damage characteristics of composite structures under impact loads is important to the safety of underground engineering construction. First, dynamic compression tests on different grades of mortar-sandstone composite specimens were carried out by using a Hopkinson pressure bar system to discuss the effect of impact velocities on the mechanical properties and failure modes of composite specimens. The results show that the dynamic peak stress, strain energy density and fragmentation block of the mortar-sandstone composite have an obvious strain rate effect. With an increase in impact velocity, the internal cracks of the sample do not have sufficient time to expand, and the energy absorbed by the sample leads to the continuous initiation of new cracks in the sample, resulting in an increasing damage degree of composite specimens. The increase in mortar strength can significantly increase the peak stress, improve the load-bearing capacity of the sample, and reduce the degree of sample damage. At the same impact velocity, the fragmentation degree of the mortar sample is more severe than that of sandstone, and the mortar sample is broken into powder debris, while the sandstone is broken into fragments. In addition, according to the failure properties of the composite sample, the mortar and sandstone samples are described by different damage models, and the dynamic damage constitutive model of the mortar-sandstone composite is established based on the overlay principle. The dynamic test results were fitted. The research shows that the fitting curves of the model are well fitted with the test curves and that the model accurately reflects the changes in the mechanical parameters of the composite specimens.

Analysis of Esophageal Cancer Time Trends in China, 1989-2008

Zhao, Jun,He, Yu-Tong,Zheng, Rong-Shou,Zhang, Si-Wei,Chen, Wan-Qing Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9

National cancer incidence data were utilized to analyze trends in esophageal cancer incidence in China in order to provide basic information for making cancer control strategy. We retrieved and re-sorted valid esophageal cancer incidence data from National Central Cancer Registry Database over 20 years period from 1989 to 2008. Crude incidence and age-standardized incidence rates were calculated for analysis, with annual percent change estimated by Joinpoint software for long term trend analysis. The crude incidence rate of esophageal cancer was found to have remained relatively stable in both urban and rural areas over the 20 year period. Age standardized incidence rate (ASR) in cancer registration areas decreased from 39.5/100,000 in 1989 to 23.0/100,000 in 2008 in all areas (AAPC=-3.3%, 95% CI:-2.8~-3.7). The trend was no change in urban areas and 2.1% average annual decrease observed in rural aras. Before the year of 2000, esophageal cancer incidence rates significant decreased with 2.8% annually and then the rates kept stable. Over 20 years from 1989 to 2008, esophageal cancer age standardized incidence rate in cancer registration areas decreased with time. However, esophageal cancer is still a big issue and efforts for control should be continuously enhanced. Cancer registration is playing an important role in cancer control with the number of registries increasing and data quality improving in China.

Electronic Structure, Phase Transition, and Elastic Properties of ScC under High Pressure

Yu-Xin Zhao,Jun Zhu,Yan-Jun Hao,Zi-Yuan Li,Long-Qing Chen,Guang-Fu Ji 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.67 No.12

The structural properties and the phase transition for scandium carbide (ScC) have been studied in NaCl (B1), CsCl (B2), ZB (B3), WZ (B4), NiAs (B81), WC (Bh), and Pmmn structures by using the pseudopotential plane-wave method in the framework of the density functional theory. Our theoretical results show that the most stable structure is the B1 phase, contrary to the result of Rahim et al. The phase transitions B1 ! Pmmn and Pmmn ! B2 are predicted at 83.7 and 109.7 GPa, respectively. At the same time, we find that the B3, B4, B81, and Bh phases are not stable over the whole pressure range considered. In particular, the elastic constants of Pmmn-ScC under high pressure are obtained successfully. The effects of pressure on the elastic properties of B1-ScC and Pmmn-ScC are also predicted. The Debye temperatures and the sound velocities of these two structures are estimated from the elastic constants, and by analyzing G/B, the brittle-ductile behavior of ScC is assessed. In addition, the density of states of B1-ScC at high pressures is also discussed.

Analysis on the creep response of bolted rock using bolted burgers model

Zhao, Tong-Bin,Zhang, Yu-Bao,Zhang, Qian-Qing,Tan, Yun-Liang Techno-Press 2018 Geomechanics & engineering Vol.14 No.2

In this paper, the creep behavior of bolted rock was analyzed by using the unconfined creep tests and the numerical results. Based on the test results, the Bolted Burgers creep model (B-B model) was proposed to clarify the creep mechanism of rock mass due to rock bolts. As to the simulation of the creep behaviour of bolted rock, a new user-defined incremental iterative format of the B-B model was established and the open-source $FLAC^{3D}$ code was written by using the object-oriented language (C++). To check the reliability of the present B-B creep constitutive model program, a numerical model of a tunnel with buried depth of 1000 m was established to analyze the creep response of the tunnel with the B-B model support, the non-support and the bolt element support. The simulation results show that the present B-B model is consistent with the calculated results of the inherent bolt element in $FLAC^{3D}$, and the convergence deformation can be more effectively controlled when the proposed B-B model is used in the $FLAC^{3D}$ software. The big advantage of the present B-B creep model secondarily developed in the $FLAC^{3D}$ software is the high computational efficiency.

Effect of Circuit Parameters on Stability of Voltage-fed Buck-Boost Converter in Discontinuous Conduction Mode

Zhao-He Feng,Ren-Xi Gong,Qing-Yu Wang 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.4

The state transition matrix are obtained by solving state equations in terms of Laplace inverse transformation and Cayley-Hamilton theorem, and an establishment of a precise discreteiterative mapping of the voltage-fed buck-boost converter operating in discontinuous conduction mode is made. On the basis of the mapping, the converter bifurcation diagrams and Lyapunov exponent diagrams with the input voltage, the resistance, the inductance and the capacitance as the bifurcation parameters are obtained, and the effect of the parameters on the system stability is deeply studied. The results obtained show that they have a great influence on the stability of the system, and the general trend is that the increase of either the voltage-fed coefficient, input voltage or the load resistance, or the decrease of the filtering inductance, capacitance will make the system stability become poorer, and that all the parameters have a critical value, and when they are greater or less than the values, the system will go through stable 1T orbits, stable 2T orbits, 4T orbits, 8T orbits and eventually approaches chaos.

Control Strategy for Buck DC/DC Converter Based on Two-dimensional Hybrid Cloud Model

Qing-Yu Wang,Ren-Xi Gong,Li-Wen Qin,Zhao-He Feng 대한전기학회 2016 Journal of Electrical Engineering & Technology Vol.11 No.6

In order to adapt the fast dynamic performances of Buck DC/DC converter, and reduce the influence on converter performance owing to uncertain factors such as the disturbances of parameters and load, a control strategy based on two-dimensional hybrid cloud model is proposed. Firstly, two cloud models corresponding to the specific control inputs are determined by maximum determination approach, respectively, and then a control rule decided by the two cloud models is selected by a rule selector, finally, according to the reasoning structure of the rule, the control increment is calculated out by a two-dimensional hybrid cloud decision module. Both the simulation and experiment results show that the strategy can dramatically improve the dynamic performances of the converter, and enhance the adaptive ability to resist the random disturbances, and its control effect is superior to that of the current-mode control.

Identification of a Novel Human Zinc Finger Gene, ZNF438, with Transcription Inhibition Activity

( Zhao Min Zhong ),( Bo Wan ),( Yun Qiu ),( Jun Ni ),( Wen Wen Tang ),( Xin Ya Chen ),( Yun Yang ),( Su Qin Shen ),( Ying Wang ),( Mei Rong Bai ),( Qing Yu Lang ),( Long Yu ) 생화학분자생물학회 2007 BMB Reports Vol.40 No.4

Association of Lipoprotein-Associated Phospholipase A_2 with Characteristics of Vulnerable Coronary Atherosclerotic Plaques

Yu-Sheng Liu,Qing-Hua Lu,Xiao-Bo Hu,Hong-Zhuan Li,Wei-Dong Jiang,Xin Wang,Hao Lin,Ai-Qiong Qin,Yong-Mei Wang,Tong Zhao,Zhao-Qiang Dong,Mei Zhang 연세대학교의과대학 2011 Yonsei medical journal Vol.52 No.6

Purpose: Lipoprotein-associated phospholipase A2 (Lp-PLA_2) is an inflammatory enzyme expressed in atherosclerotic plaques. We investigated the association of circulating Lp-PLA_2 with characteristics of vulnerable coronary atherosclerotic plaques. Materials and Methods: We recruited 113 patients with either unstable angina (UA, n=59) and stable angina (SA, n=54) by coronary angiography. Thirty-six healthy subjects served as controls. Intravascular ultrasound (IVUS) was used to evaluate the characteristics of coronary atherosclerotic plaque, and serum Lp-PLA2 concentration was measured as well. Results: Lp-PLA_2 concentration was significantly higher in both UA and SA patients [(396±36) μg/L and (321±39) μg/L, respectively]compared with the controls [(127±49) μg/L, p<0.01], and higher in UA than SA group. IVUS findings showed that remodeling index (RI) (0.91±0.15 vs. 0.85±0.11, p=0.005) and eccentricity index (EI) (0.73±0.16 vs. 0.65±0.22, p=0.039) were larger in UA than in SA group, and fibrous caps were thicker in SA than UA group [(0.91±0.23) mm vs. (0.63±0.21) mm, p=0.032]. Moreover, Lp-PLA_2 correlated positively with EI (r=0.439, p<0.01) and RI (r=0.592, p<0.05) in UA group. There was an inverse relationship between Lp-PLA_2 and fibrous cap thickness in both UA (r=-0.587, p<0.001) and SA (r=-0.318, p<0.05) groups. The independent risk factors in UA group were Lp-PLA_2 (OR=1.055, 95% CI: 1.03-1.08, p=0.013), LDL-cholesterol (OR=0.032, 95% CI: 0.00-0.05, p=0.041) and fibrous cap thickness (OR=0.008, 95% CI: 0.00-0.45, p=0.019). Lp-PLA_2 was strongly associated with both EI and fibrous cap thickness in both groups. Conclusion: Serum level of Lp-PLA_2 is associated with both eccentricity index and fibrous cap thickness in both UA and SA groups. Elevated levels of circulating Lp-PLA_2 might to be a strong risk factor and more serious for unstable angina than stable angina.

Streptomyces xinghaiensis sp. nov., isolated from marine sediment.

Zhao, Xin-Qing,Li, Wen-Jun,Jiao, Wen-Ce,Li, Yan,Yuan, Wen-Jie,Zhang, Yu-Qin,Klenk, Hans-Peter,Suh, Joo-Won,Bai, Feng-Wu Society for General Microbiology 2009 International journal of systematic and evolutiona Vol.59 No.11

<P>A novel actinomycete, strain S187(T), was isolated from a marine sediment sample collected from Xinghai Bay, Dalian, China. Growth occurred on ISP medium 2 containing 0-9 % NaCl and at pH 6.0-9.0 and 10-45 degrees C. The cell wall of strain S187(T) contained the isomer ll-diaminopimelic acid as the diagnostic diamino acid. The predominant menaquinones were MK-9(H(6)) (40.8 %), MK-9(H(8)) (38.2 %) and MK-9(H(2)) (8.8 %). The major fatty acids were iso-C(16 : 0) (29.6 %), anteiso-C(15 : 0) (14.0 %) and anteiso-C(17 : 0) (11.6 %). Cells contained phosphatidylethanolamine, phosphatidylinositol, phosphatidylglycerol, phosphatidylinositol mannosides and one unknown phospholipid. The G+C content of the genomic DNA was 72.01 mol%. The 16S rRNA gene sequence of the isolate had similarities of 98.1 and 97.5 % with those of Streptomyces flavofuscus NRRL B-8036(T) (=DSM 41426(T)) and Streptomyces albiaxialis DSM 41799(T), respectively, showing that the novel strain should be assigned to the genus Streptomyces. DNA-DNA hybridizations with the two above-mentioned Streptomyces species showed 31.4 and 46.9 % relatedness, respectively. Moreover, the three strains differed in some physiological and biochemical properties. Thus, on the basis of phenotypic and genotypic analyses, it is proposed that strain S187(T) represents a novel species of the genus Streptomyces, for which the name Streptomyces xinghaiensis sp. nov. is proposed; the type strain is S187(T) (=NRRL B-24674(T)=CCTCC AA 208049(T)=KCTC 19546(T)).</P>

Continuous DC-CIK Infusions Restore CD8⁺ Cellular Immunity, Physical Activity and Improve Clinical Efficacy in Advanced Cancer Patients Unresponsive to Conventional Treatments

Zhao, Yan-Jie,Jiang, Ni,Song, Qing-Kun,Wu, Jiang-Ping,Song, Yu-Guang,Zhang, Hong-Mei,Chen, Feng,Zhou, Lei,Wang, Xiao-Li,Zhou, Xin-Na,Yang, Hua-Bing,Ren, Jun,Lyerly, Herbert Kim Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.6

Background: There are few choices for treatment of advanced cancer patients who do not respond to or tolerate conventional anti-cancer treatments. Therefore this study aimed to deploy the benefits and clinical efficacy of continuous dendritic cell-cytokine induced killer cell infusions in such patients. Materials and Methods: A total of 381 infusions (from 67 advanced cases recruited) were included in this study. All patients underwent peripheral blood mononuclear cell apheresis for the following cellular therapy and dendritic cells-cytokine induced killer cells were expanded in vitro. Peripheral blood T lymphocyte subsets were quantified through flow cytometry to address the cellular immunity status. Clinical efficacy and physical activities were evaluated by RECIST criteria and Eastern Cooperative Oncology Group scores respectively. Logistic regression model was used to estimate the association between cellular infusions and clinical benefits. Results: An average of $5.7{\pm}2.94{\times}10^9$ induced cells were infused each time and patients were exposed to 6 infusions. Cellular immunity was improved in that cytotoxic $CD8^+CD28^+$ T lymphocytes were increased by 74% and suppressive $CD8^+CD28^-$ T lymphocytes were elevated by 16% (p<0.05). Continuous infusion of dendritic cells-cytokine induced killer cells was associated with improvement of both patient status and cellular immunity. A median of six infusions were capable of reducing risk of progression by 70% (95%CI 0.10-0.91). Every elevation of one ECOG score corresponded to a 3.90-fold higher progression risk (p<0.05) and 1% increase of $CD8^+CD28^-$ T cell proportion reflecting a 5% higher risk of progression (p<0.05). Conclusions: In advanced cancer patients, continuous dendritic cell-cytokine induced killer cell infusions are capable of recovering cellular immunity, improving patient status and quality of life in those who are unresponsive to conventional cancer treatment.