Dynamic behavior analysis of push-the-bit rotary steerable bottom hole assembly

Zhi-chuan Guan,Heng Wang,Yu-cai Shi,Wei-qing Chen,Guo-shan Zhao,Jian-yun Wang,Guang-qiang Cao 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.4

Rotary steerable drilling technology is currently an advanced technology in the field of drilling engineering. A good understanding of dynamic behavior of rotary steerable system will benefit the drilling progress. Aimed at push-the-bit type of rotary steerable tool, finite element method was employed to model the rotary steerable bottom hole assembly (RSBHA) and establish the motion equation. Contact interaction between drill string and wellbore wall was analyzed and taken as the constraint condition in solving RSBHA motion equation. Force applied by steering pads was as the external force acting at the pads node. Then RSBHA motion state and bit lateral force were obtained by using Newmark method to solve the motion equation. A case was given and effects of influencing factors were analyzed. The results show that stick-slip phenomenon occurs under 60 r/min rotary speed condition and disappears when rotary speed rises to 90 r/min. Fully developed backward whirl comes into being at the near-bit stabilizer when rotary speed increases to 120 r/min. High weight on bit intensifies bit torsional vibration while larger pads’ steering force decreases the bit torsional vibration. Upper stabilizer plays a part in weakening RSBHA backward whirl under high rotary speed condition but reduces the inclination force. Time average of bit lateral force is mainly determined by pads’ steering force. Based on the results, corresponding suggestions were proposed to make the RSBHA be better used in the field applications.

Survey of Corrosion Cost in China and Preventive Strategies

( Wei Ke ),( Zhi Qiang Li ) 한국부식방식학회(구 한국부식학회) 2008 Corrosion Science and Technology Vol.7 No.5

In Vivo Detection of Lipid-Core Plaques by Coronary CT Angiography: A Head-to-Head Comparison with Histologic Findings

Wei-hua Yin,Yan Zhang,Xiang-nan Li,Hong-yue Wang,Yun-qiang An,Yang Sun,Zhi-hui Hou,Yang Gao,Bin Lu,Zhe Zheng 대한영상의학회 2020 Korean Journal of Radiology Vol.21 No.2

Objective: We sought to distinguish lipid plaques using a CT quantitative pixel density histogram, based on the pathological diagnosis of lipid cores as the gold standard. Materials and Methods: Eight patients awaiting heart transplantation due to end-stage coronary heart disease underwent coronary CT angiography (CCTA) spectroscopy prior to heart transplantation; coronary artery pathological analysis was performed for all patients. Lipid-core plaques were defined pathologically as manifesting a lipid core diameter > 200 μm, a circumference > 60 degrees, and a cap thickness < 450 μm. The percentage distributions of CT pixel attenuation ≤ 20, 30, 40, and 50 HU were calculated using quantitative histogram analysis. Results: A total of 271 transverse sections were co-registered between CCTA and pathological analysis. Overall, 26 lipid cores and 16 fibrous plaques were identified by pathological analysis. There was no significant difference in median CT attenuation between the lipid and fibrous plaques (51 HU [interquartile range, 46–63] vs. 57 HU [interquartile range, 50–64], p = 0.659). The median percentage of CT pixel attenuation ≤ 30 HU accounted for 11% (5–17) of lipid-core plaques and 0% (0–2) of fibrous plaques (p < 0.001). The sensitivity and specificity of the method for diagnosing lipid plaques by the average CT pixel attenuation ≤ 30 HU were 80.8% and 87.5%, respectively. The area under the receiver operator characteristics curve was 0.898 (95% confidence interval: 0.765–0.970; 3.0% was the best cut-off value). The diagnostic performance was significantly higher than those of the average pixel CT attenuation percentages ≤ 20, 40, and 50 HU and the mean CT attenuation (p < 0.05). Conclusion: In in vivo conditions, with the pathological lipid core as the gold standard, quantification of the percentage of average CT pixel attenuation ≤ 30 HU in the histogram can be useful for accurate identification of lipid plaques.

공기분위기 하에서 열처리된 고입체 규칙성 폴리아크릴로니트릴의 XRD에 환화반응 속도 연구

Zhi Xian Xu,Jing Xu,Liang Hua Xu,Yong Qiang Dai,Li Wei Xue,Ri Guang Jin 한국고분자학회 2008 폴리머 Vol.32 No.2

Synthesis, Characterization and pH-Responsive Self-Assembly Behavior of Amphiphilic Multiarm Star Triblock Copolymers Based on PCL, PDEAEMA, and PEG

You Qiang Yang,Wen Jing Lin,Li Juan Zhang,Cheng Zhi Cai,Wei Jiang,Xin Dong Guo,Yu Qian 한국고분자학회 2013 Macromolecular Research Vol.21 No.9

A series of amphiphilic 4- and 6-armed star triblock copolymers based on poly(ε-caprolactone) (PCL),poly(2-(diethylamino)ethyl methacrylate) (PDEAEMA), and poly(poly(ethylene glycol) methyl ether methacrylate)(PPEGMA) were designed and synthesized by a combination of ring opening polymerization (ROP) and continuous activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). The continuous ARGET ATRP of DEAEMA and PEGMA was in situ monitored by react infrared spectroscopy (ReactIR) and showed good first-order kinetic characteristics. The molecular weights and chemical structures of the copolymers and their precursors were confirmed by gel permeation chromatography (GPC) and 1H NMR. The critical micelle concentration (CMC) values of the star copolymers in aqueous solution were extremely low (2.2-4.0 mg/L), depending on the architecture of the copolymers. The pH-responsive self-assembly behavior of the star copolymers in aqueous solution was investigated by a combination of dynamic light scattering (DLS), UV-vis spectrometry and scanning electron microscopy (SEM). When the pH values decreased from 10 to 3, no obvious fluctuation of the visible light transmittance of the micelle solutions was observed for lower polymer concentrations of 0.1 and 1 mg/mL, while sharp increase occurred at higher concentration of 10 mg/mL. The hydrodynamic diameters (Dh) of the micelle solutions appeared slight increase with the increase of concentration, and increased rapidly as the pH decreased from 10 to 4 followed by a slight decrease at pH 3. The effects of pH value on the zeta potentials exhibited almost the same tendency with the Dh. This may due to the fact that the protonation of tertiary amine groups in DEAEMA can induce the swelling of micelles. The PCL and PDEAEMA contents and the topological structures (4-or 6-arm) showed significant influences on the pH-sensitivity of the micelles. Overall, the results demonstrated that the structures and pH-sensitivity of these amphiphilic copolymers could be well-controlled and their self-assembled micelles are promising carriers for delivery of anticancer hydrophobic drugs.

Stratigraphic Sequence and Deposition-affected Compressibility of Fine-grained Sediments in the Ancient Yellow River Delta during the Late Pleistocene and Holocene

Ming-Zhi Zhao,Qiang Luo,Liang-Wei Jiang,Ming Wei 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.1

To investigate the stratigraphic sequence in the ancient Yellow River Delta and further discuss the correlation of compressibility of undisturbed soils with depositional environments, two boreholes were drilled at Liyao test site in Cangzhou, Hebei Province, China. Some basic tests regarding to index properties were performed on sediments from one borehole, and oedometer test was conducted for the “undisturbed samples” collected from the other. The stratigraphic sequence in the study area is classified into four depositional systems in terms of sedimentation environment. Evaluation of sample disturbance shows that the “undisturbed samples” for oedometer test are just slightly disturbed in the sampling process. Since overall compressibility can be divided into intrinsic compressibility and additional one, the environmental factors that can affect soil microstructure are closely correlated with additional compressibility. Thus, the influencing mechanism of depositional rate on additional void index ΔIv was investigated quantitatively. Moreover, the relationship between floating range of yield stress and buried depth is established. Then, the additional compressibility of undisturbed samples can be evaluated with depositional rate and buried depth. Finally, the predicted overall compression curve with the proposed method in this study is compared with the measured curve to verify the reasonability and feasibility.

An Effective Method for Extraction of Glutaryl-7-aminocephalosporanic Acid Acylase from Recombinant E. coli Cells

Xiao-qiang Ma,Er-zheng Su,Sen-wen Deng,Dong-zhi Wei 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4

In this study, several chemical treatment techniques commonly used for protein extraction were investigated for recovering glutaryl-7-aminocephalosporanic acid acylase (GLA) from recombinant E. coli cells. The best results were obtained by the combined use of cetyltrimethylammonium bromide (CTAB) and KCl. Subsequently, various extraction conditions, such as cation salt, concentrations of CTAB and KCl, extraction temperature, extraction time, and biomass, were optimized to further enhance the release yield and specific activity of GLA. Our results showed that 110% of GLA was released after treatment with 0.5% CTAB (w/v, %) and 0.3 M KCl at 10°C for 12 h, and its specific activity in this extracting solution was approximately 1.5 times higher as compared to that obtained by sonication. This extraction method could avoid the inactivation of GLA caused by drastic mechanical methods, and also enhance its specific activity for industrial extraction.

Anti-proliferative Effects of Atractylis lancea (Thunb.) DC. via Down-regulation of the c-myc/hTERT/Telomerase Pathway in Hep-G2 Cells

Guo, Wei-Qiang,Li, Liang-Zhi,He, Zhuo-Yang,Zhang, Qi,Liu, Jia,Hu, Cui-Ying,Qin, Fen-Ju,Wang, Tao-Yun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.11

Atractylis lancea (Thunb.) DC. (AL), an important medicinal herb in Asia, has been shown to have anti-tumor effects on cancer cells, but the involved mechanisms are poorly understood. This study focused on potential effects and molecular mechanisms of AL on the proliferation of the Hep-G2 liver cancer cell line in vitro. Cell viability was assessed by MTT test in Hep-G2 cells incubated with an ethanol extract of AL. Then, the effects of AL on apoptosis and cell cycle progression were determined by flow cytometry. Telomeric repeat amplification protocol (TRAP) assays was performed to investigate telomerase activity. The mRNA and protein expression of human telomerase reverse transcriptase (hTERT) and c-myc were determined by real-time RT-PCR and Western blotting. Our results show that AL effectively inhibits proliferation in Hep-G2 cells in a concentrationand time-dependent manner. When Hep-G2 cells were treated with AL after 48h,the $IC_{50}$ was about 72.1 ${\mu}g/mL$. Apoptosis was induced by AL via arresting the cells in the G1 phase. Furthermore, AL effectively reduced telomerase activity through inhibition of mRNA and protein expression of hTERT and c-myc. Hence, these data demonstrate that AL exerts anti-proliferative effects in Hep-G2 cells via down-regulation of the c-myc/hTERT/telomerase pathway.

Clinical Application of Endoscopic Inguinal Lymph Node Resection after Lipolysis and Liposuction for Vulvar Cancer

Wu, Qiang,Zhao, Yi-Bing,Sun, Zhi-Hua,Ni, Jing,Wu, Yu-Zhong,Shao, Heng-Hua,Qu, Jun-Wei,Huang, Xin-En Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.12

Aim: To examine lymph nodes obtained after lipolysis and liposuction of subcutaneous fat of the inguinal region of female vulvar cancer patients to explore the feasibility of clinical application. Methods: The field of operation was on the basis of the range of the conventional resection of inguinal lymph nodes. We injected lipolysis liquid fanwise, started liposuction after 15-20 minutes; then the subcutaneous fatty tissue was sucked out clearly by suction tube. We selected the first puncture holes located on 2-3 cm part below anterior superior spine, the others respectively being located 3cm and 6cm below the first for puncturing into the skin, imbedding a trocar to intorduce $CO_2$ gas and the specular body, and excise the lymph nodes by ultrasonic scalpel. The surgical field chamber was set with negative pressure drainage and was pressured with a soft saline bag after surgery. Results: A lacuna emerged from subcutaneous of the inguinal region after lipolysis and liposuction, with a wide fascia easily exposed at the bottom where lymph nodes could be readily excised. The number of lymph nodes of ten patients excised within the inguinal region on each side was 4-18. The excised average number of lymph nodes was 11 when we had mature technology. Conclusion: Most of adipose tissue was removed after lipolysis and liposuction of subcutaneous tissue of inguinal region, so that the included lymph nodes were exposed and easy to excise by endoscope. This surgery avoided the large incision of regular surgery of inguinal region, the results indicating that this approach is feasible and safe for used as an alternative technology.

Down-regulation of Phosphoglucose Isomerase/Autocrine Motility Factor Enhances Gensenoside Rh2 Pharmacological Action on Leukemia KG1α Cells

You, Zhi-Mei,Zhao, Liang,Xia, Jing,Wei, Qiang,Liu, Yu-Min,Liu, Xiao-Yan,Chen, Di-Long,Li, Jing Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.3

Aims and Background: Ginsenoside Rh2, which exerts the potent anticancer action both in vitro and in vivo, is one of the most well characterized ginsenosides extracted from ginseng. Although its effects on cancer are significant, the underlying mechanisms remain unknown. In this study, we sought to elucidate possible links between ginsenoside Rh2 and phosphoglucose isomerase/autocrine motility factor (PGI/AMF). Methods: $KG1{\alpha}$, a leukemia cell line highly expressing PGI/AMF was assessed by western blot analysis and reverse transcription- PCR (RT-PCR) assay after transfection of a small interfering (si)-RNA to silence PGI/AMF. The effect of PGI/AMF on proliferation was measured by typan blue assay and antibody array. A cell counting kit (CCK)-8 and flow cytometry (FCM) were adopted to investigate the effects of Rh2 on PGI/AMF. The relationships between PGI/AMF and Rh2 associated with Akt, mTOR, Raptor, Rag were detected by western blot analysis. Results: KG1${\alpha}$ cells expressed PGI/AMF and its down-regulation significantly inhibited proliferation. The antibody array indicated that the probable mechanism was reduced expression of PARP, State1, SAPK/JNK and Erk1/2, while those of PRAS40 and p38 were up-regulated. Silencing of PGI/AMF enhanced the sensibility of $KG1{\alpha}$ to Rh2 by suppressing the expression of mTOR, Raptor and Akt. Conclusion: These results suggested that ginsenoside Rh2 suppressed the proliferation of $KG1{\alpha}$, the same as down-regulation of PGI/AMF. Down-regulation of PGI/AMF enhanced the pharmacological effects of ginsenoside Rh2 on KG1${\alpha}$ by reducing Akt/mTOR signaling.