Effects of Grouting Defects in a Duct on the Bonding of Prestressing Strands

Rong Guo,Zhichao Zhen,Shaowei Zhao,Cunan Li 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.4

Insufficient grouting has a great effect on the bonding performance of pressing stand for a post-tensioned prestressed concrete beam, which leads to a decrease of beam’s bending capacity. This study focused on the influence of defects of local grouting length and grouting fullness on the prestressing strand’s bond performance. The prestressing strand pull-out test was used to evaluate the bonding performance of pressing stand with different defects of local grouting length and grouting fullness. The results indicate that two forms of grouting defects reduce the bonding properties of a prestressing strand, when the slip of the free end of prestressing strand is 0.12 mm (s = 0.12 mm), the bond stress decreases briefly. To analyze the bonding mechanism of the prepressing strand in duct, the bond stresses τ0 and τu at s = 0.12 mm and s = 25 mm were adopted as the characteristic parameters of bond stress to deduce the calculation formula of the bond strength by fitting the test data. A bond-slip constitutive model of prestressing strand in duct under two classes defects was proposed by improving the modified Eligehausen, Popov and Bertero (BPE) model of fiber reinforced polymer (FRP) rebars.

Effects of Stellate Ganglion Block on the Peri-operative Vasomotor Cytokine Content and Intrapulmonary Shunt in Patients with Esophagus Cancer

Guo, Wei,Jin, Xiao-Ju,Yu, Jun,Liu, Yang,Zhang, Jian-Ping,Yang, Da-Wei,Zhang, Lei,Guo, Jiang-Rong Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.21

Objective: To investigate the effects of stellate ganglion block (SGB) on the peri-operative vasomotor cytokine content and intrapulmonary shunt in patients with esophagus cancer who underwent thoracotomy. Materials and Methods: Forty patients undergoing elective resection of esophageal cancer patients who had I~II American Society of Anesthesiologist (ASA) were randomly divided into total intravenous anesthesia group (group N, n=20) and total intravenous anesthesia combined with SGB group (group S, n=20, 0.12 mL/kg 1% lidocaine was used for SGB 10 min before induction). Heart rate (HR), mean arterial pressure (MAP), central venous pressure (CVP), mean pulmonary arterial pressure (MPAP) and continuous cardiac output (CCO) were continuously monitored. The blood from internal jugular vein was drawn respectively before induction ($T_0$), and 30 min ($T_1$), 60 min ($T_2$) and 120 min ($T_3$) after one-lung ventilation (OLV), and 30 min (T4) after two-lung ventilation. The contents of plasma endothelin (ET), nitric oxide (NO) and calcitonin gene-related peptide (CGRP) were detected with enzyme linked immunosorbent assay (ELISA). Meanwhile, arterial and mixed venous blood samples were collected for determination of blood gas and calculation of intrapulmonary shunt fraction (Qs/Qt). Results: During OLV, ET contents were increased significantly in two groups (P<0.05), and no significant difference was presented (P>0.05). NO content in group S was obviously higher than in group N at T3 (P<0.05), whereas CGRP content in group N was markedly lower than in group S at each time point (P<0.05). Qs/Qt was significantly increased in both groups after OLV, but there was no statistical significant regarding the Qs/Qt at each time point between two groups. Conclusions: Total intravenous anesthesia combined with SGB is conducive to regulation of perioperative vasomotor cytokines in thoracotomy, and has little effect on intrapulmonary shunt at the time of OLV.

Region Stability Analysis for Switched Nonlinear Systems with Multiple Equilibria

Rong-Wei Guo,Yuzhen Wang 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.2

This paper investigates the region stability analysis for switched nonlinear systems whose subsystemshave different equilibria, which are referred to multi-equilibrium switched nonlinear systems, and proposes a numberof new results on the region stability analysis. Through investigating the dynamical behavior of the multiequilibriumswitched system, two methods are established, based on which several new results are then obtainedfor the region stability. It is shown that the main results obtained in this paper not only guarantee the region stabilityof the multi-equilibrium switched nonlinear system under arbitrary switching, but also provide several newapproaches to determine the corresponding regions of convergence. Moreover, an improved average dwell time(ADT) method is proposed for the stability of switched nonlinear systems whose subsystems do not share a commonLyapunov function. Finally, an illustrative example with numerical simulation is studied by using the obtainedresults. The study of example shows that our results work very well in analyzing the region stability of somemulti-equilibrium switched nonlinear systems.

Varistor and dielectric properties of Cr2O3 doped SnO2eZn2SnO4 composite ceramics

Guo-Zhong Zang,Feng-Zi Zhou,Jing-Xiao Cao,Xiao-Fei Wang,Zhao-Wu Wang,Li-Ben Li,Guo-Rong Li 한국물리학회 2014 Current Applied Physics Vol.14 No.12

Cr2O3 doped SnO2eZn2SnO4 composite ceramics were prepared by traditional ceramic processing and the varistor, dielectric properties were investigated. With increasing Cr2O3 content, the breakdown electrical field EB increases from 11 to 92 V/mm and the relative dielectric constant εr measured at 1 kHz, 50 C decreases from 11,028 to 3412, respectively. The barrier height fB about 0.8e0.84 eV and the decreasing of SnO2 grain size suggest that the varistor behavior with high εr is originated from SnO2 eSnO2 or SnO2eZn2SnO4 grain boundary. In the dielectric spectra lower than 1 kHz, a dielectric peak is presented and depressed with increasing bias voltage. Similarly, at high temperature, the dielectric constant also presents a dielectric peak in the temperature spectra and the peak becomes faint with increasing frequency. The exhibition of the dielectric peak is thought to be attributed to the conduction of grain boundary since it is accompanied by the sharp increase of dielectric loss. In addition, a dielectric relaxation with the activation energy about 0.4e0.5 eV was observed in the temperature range of 20 e100 C. Based on the results, the formation mechanism of Schottky barriers at grain boundaries and the varistor behavior with high dielectric constant are well understood.

Research Advances of Leptotrombidium scutellare in China

Rong Xiang,Xian-Guo Guo 대한기생충학열대의학회 2021 The Korean Journal of Parasitology Vol.59 No.1

Impact of Allogenic and Autologous Transfusion on Immune Function in Patients with Tumors

Guo, Jian-Rong,Xu, Feng,Jin, Xiao-Ju,Shen, Hua-Chun,Liu, Yang,Zhang, Yi-Wei,Shao, Yi Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.1

Objective: To observe the effects of allogeneic and autologous transfusion on cellular immunity, humoral immunity and secretion of serum inflammatory factors and perforin during the perioperative period in patients with malignant tumors. Methods: A total of 80 patients (age: 38-69 years; body weight: 40-78 kg; ASA I - II) receiving radical operation for gastro-intestinal cancer under general anesthesia were selected. All the patients were divided into four groups based on the methods of infusion and blood transfusion: blank control group (Group C), allogeneic transfusion group (group A), hemodiluted autotransfusion Group (Group H) and hemodiluted autotransfusion + allogenic transfusion Group (A+H group). Venous blood was collected when entering into the surgery room ($T_0$), immediately after surgery ($T_1$) and 24h ($T_2$), 3d ($T_3$) and 7d ($T_4$) after surgery, respectively. Moreover, flow cytometry was applied to assess changes of peripheral blood T cell subpopulations and NK cells. Enzyme linked immunosorbent assays were performed to determine levels of IL-2, IL-10, TNF-${\alpha}$ and perforin. Immune turbidimetry was employed to determine the changes in serum immunoglobulin. Results: Both CD3+ and NK cells showed a decrease at $T_1$ and $T_2$ in each group, among which, in group A, CD3+ decreased significantly at $T_2$ (P<0.05) compared with other groups, and CD3+ and NK cell reduced obviously only in group A at $T_3$ and $T_4$ (P<0.05). CD4+ cells and the ratio of D4+/CD8+ were decreased in groups A, C and A+H at $T_1$ and $T_2$ (P<0.05). No significant intra- and inter-group differences were observed in CD8+ of the four groups (P<0.05). IL-2 declined in group C at $T_1$ and $T_2$ (P<0.05) and showed a decrease in group A at each time point (P<0.05). Moreover, IL-2 decreased in group A + H only at $T_1$. No significant difference was found in each group at $T_1$ (P<0.05). More significant decrease in group ?? at $T_2$, $T_3$ and $T_4$ compared with group A (P<0.05), and there were no significant differences among other groups (P>0.05). IL-10 increased at $T_1$ and $T_2$ in each group (P<0.05), in which it had an obvious increase in group A, and increase of IL-10 occurred only in group A at $T_3$ and $T_4$ (P<0.05). TNF-${\alpha}$ level rose at $T_1$ (P<0.05), no inter- and intra-group difference was found in perforin in all groups (P<0.05). Compared with the preoperation, both IgG and IgA level decreased at $T_1$ in each group (P<0.05), and they declined only in Group A at $T_2$ and $T_3$ (P<0.05), and these parameters were back to the preoperative levels in other groups. No significant differences were observed between preoperative and postoperative IgG and IgA levels in each group at $T_4$ (P>0.05). No obvious inter- and intra-group changes were found in IgM in the four groups (P>0.05). Conclusions: Allogeneic transfusion during the perioperative period could obviously decrease the number of T cell subpopulations and NK cells and the secretion of stimulating cytokines and increase the secretion of inhibiting cytokines in patients with malignant tumors, thus causing a Th1/Th2 imbalance and transient decreasing in the content of plasma immune globulin. Autologous transfusion has little impact and may even bring about some improvement oo postoperative immune function in patients with tumors. Therefore, cancer patients should receive active autologous transfusion during the perioperative period in place of allogeneic transfusion.

FRP Flexural Strengthened Concrete Member Design Method of Based on Early-Warning Fuses

Rong Guo,Shuo Ning,Shaowei Zhao,Minghao Wang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.11

The bearing capacity of members strengthened with prestressed carbon fiber reinforced plastic is improved significantly, however, the ductility of the members strengthened are reduced obviously. Moreover, no sign are observed before the failure and the failure process rapidly. The current study proposed a reinforcement method based on early-warning fuses theory to address this issue and took carbon fiber reinforced plastic as an example. First, it's necessary to determine the area of carbon fiber board and the application of prestressed in each part of the member (early-warning fuses part and load-bearing part). This needs to be determined by the basic safety reserve and the additional safety reserve of the carrying capacity, then the calculation formula are derived; second, designing six simulation beams and four test beams. Based on the comparison of the computation of the derived formula with the simulation and test results, the calculated values of the early-warning load agree well with the simulated and experimental values, and the calculated values of the ultimate load are less than the simulated and experimental values. This showed that the theoretical calculation method has high accuracy. In addition, various evaluation index prove that the members strengthened have sufficient reserves.

Acute Normovolemic Hemodilution Effects on Perioperative Coagulation in Elderly Patients Undergoing Hepatic Carcinectomy

Guo, Jian-Rong,Jin, Xiao-Ju,Yu, Jun,Xu, Feng,Zhang, Yi-Wei,Shen, Hua-Chun,Shao, Yi Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.8

Background: Acute normovolemic hemodilution (ANH) has been widely used to prevent the massive blood loss during hepatic carcinoma. The influences of ANH on coagulation function are still controversy, especially in elderly patients. The study observed ANH effects on coagulation function and fibrinolysis in elderly patients undergoing the disease. Materials and Methods: Thirty elderly patients (aged 60-70 yr) with liver cancer (ASA I or II) taken hepatic carcinectomy from February 2007 to February 2008 were randomly divided into ANH group (n=15) and control group (n=15). After tracheal intubation, patients in ANH group and control group were infused with 6% hydroxyethyl starch (130/0.4) and Ringer's solution, respectively. Blood samples were drawn from patients in both groups at five different time points: before anesthesia induction (T1), 30 min after ANH (T2), 1 h after start of operation (T3), immediately after operation (T4), and 24 h after operation (T5). Then coagulation function, soluble fibrin monomer complex (SFMC), prothrombin fragment (F1+2), and platelet membrane glycoprotein (CD62P and activated GP IIb/GP IIIa) were measured. Results: The perioperative blood loss and allogeneic blood transfusion were recorded during the surgery. The perioperative blood loss was not significantly different between two groups (p>0.05), but the volume of allogeneic blood transfusion in ANH group was significantly less than in control group ($350.0{\pm}70.7$) mL vs. ($457.0{\pm}181.3$) mL (p<0.01). Compared with the data of T1, the prothrombin time (PT) and activated partial thromboplastin time (APTT) measured after T3 were significantly longer (p<0.05) in both groups, but within normal range. There were no significant changes of thrombin time (TT) and D-dimer between two groups at different time points (p>0.05). SFMC and F1+2 increased in both groups, but were not statistically significant. PAC-1-positive cells and CD62P expressions in patients of ANH group were significantly lower than those at T1 (p<0.05) and T2-T5 (p>0.05). Conclusions: ANH has no obvious impact on fibrinolysis and coagulation function in elderly patients undergoing resection of liver cancer. The study suggested that ANH is safe to use in elderly patients and it could reduce allogeneic blood transfusion.

Design and Optimization of an Improved T-shape Linear Permanent Magnet Machines

Rong Guo,Wei He 한국자기학회 2023 Journal of Magnetics Vol.28 No.3

This paper presents an improved T-shape linear permanent magnet machine (T-LPMM) based on a traditional surface-mounted linear permanent magnet machine (SM-LPMM). The proposed topological structure aims to protect the surface of the permanent magnet from corrosion and enhance the rigidity against make highfrequency vibration. Firstly, the slotless magnetic field is predicted using finite-element method (FEM) with automatic scripting in MATLAB to consider the inset T-shape structure of PM. Then, the Schwarz-Christoffel (SC) mapping is adopted to calculate the slot effect. Afterward, a subdomain (SD) model is established to analyze the armature reaction, and Taguchi method is employed for optimization purposes. The optimized result is verified by FEM, and a comparison experiment is conducted between T-LPMM and SM-LPMM. The experimental demonstrate superior electromagnetic output performance of the proposed T-LPMM.

Characteristics Comparison before and after Lyophilization of Transferrin Modified Procationic-Liposome-Protamine-DNA Complexes (Tf-PLPD)

Zhi-Rong Zhong,Zhi-rong Zhang,Ji Liu,Yong Deng,Hong-wei Zhang,Yao Fu,Qing-guo Song,Qin He 대한약학회 2007 Archives of Pharmacal Research Vol.30 No.1

A novel non-viral gene delivery system, Procationic-Liposome-Protamine-DNA complexes (PLPD) which could further adsorb transferrin on the surface as a targeting ligand to form Tf- PLPD, was prepared and characterized before and after lyophilization. The size distribution of Tf-PLPD was in the range of 240 ± 12 nm and the zeta potential was -24.10 ± 2.5 mV. The transfection efficiencies of PLPD and Tf-PLPD were 12.18 ± 3.8 and 24.26 ± 2.6 mU β-galactosidase/ mg protein respectively. The lyophilization and the presence of serum didn’t affect the tansfectivities of PLPD or Tf-PLPD. Compared to LipofectamineTM 2000 (Invitrogen, U.S.A.), the procationic liposomes had less cytotoxicity to cells. In summary the procationic lipoplex described here, combining the condensing effect of protamine and the targeting capability of Tf, was a perspective non-viral vector for gene delivery system.