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Theoretical and Experimental Research on Rolling Force for Rail Hot Rolling by Universal Mill

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Journal of Iron and Steel Research International 2010年第1期17卷 27-32页

作者： DONG Yong-gang zhang wen-zhi SONG Jian-feng College of Mechanical Engineering Yanshan University Qinhuangdao 066004 Hebei China College ofEletromechanical Engineering Harbin Institute of Technology Harbin 150001 Heilongjiang China

For rail rolling by universal mill, a simplified three-dimensional theoretical model was built firstly. The kinematically admissible velocity field of the web, head, and base of rail was determined respectively; moreover, the corresponding strain rate field and the strength of shear strain rate were obtained. Then, the plastic deformation power of corresponding deformation zone, the power consumed on the velocity discontinuity surface, and the power generated by backward slip and forward slip were proposed. According to the upper-bound method, the roiling force of horizontal roll and two vertical rolls could be obtained. For verifying the theoretical model, the universal rolling experiments of 18 kg/m light rail was accomplished in Yanshan University Rolling Laboratory, and the experimental data of 60 kg/m heavy rail universal rolling were obtained from the Anshan Iron and Steel Group Corporation. Compared with the experimental data, the theoretical results of rolling force for 18 kg/m light rail and 60 kg/m heavy rail universal rolling were somewhat greater than experimental data, but in general did not exceed them by 15%. Thus, the simplified model was reliable and feasible for presetting and optimizing the parameters of rolling technology according to the upper-bound method.

关键词： rail rolling universal mill upper-bound method rolling force experiment

Dynamics Model of Carrier-based Aircraft Landing Gears Landed on Dynamic Deck

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Chinese Journal of Aeronautics 2009年第4期22卷 371-379页

作者： zhang wen,zhang zhi,Zhu Qidan,Xu Shiyue Department of Automation,Harbin Engineering University,Harbin 150001,China Department of Automation Harbin Engineering University Harbin 150001 China

In order to study the carrier-based aircraft landing laws landed on the carrier, the dynamics model of carrier-based aircraft landing gears landed on dynamic deck is built. In this model, the interactions of the carrier-based aircraft landing attitude and the damping force acting on landing gears are considered, and the influence of dynamic deck is introduced into the model through the deck normal vectors. The wheel-deck coordinate system is put forward to solve the complex simulation problem of force-onwheel which comes from the dynamic deck. At last, by simulation, it is demonstrated that the model can be applied to landing attitude when the carrier-based aircraft is landing on the dynamic deck, it is also proved that the model is comprehensive and suitable for any abnormal landing situation.

关键词： carrier-based aircraft landing gear deck wheel-deck coordinate system landing

What MELD score mandates use of entecavir for ACLF-HBV HBeAg-negative patients?

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World Journal of Gastroenterology 2012年第33期18卷 4604-4609页

作者： Ying Yan Li Mai Yu-Bao Zheng Shao-Quan zhang wen-Xiong Xu zhi-Liang Gao Wei-Min Ke Department of Infec-tious Diseases The Third Affiliated Hospital of Sun Yat-sen Uni-versity Guangzhou 510630 Guangdong Province China

AIM: To investigate optimal timing for therapeutic efficacy of entecavir for acute-on-chronic hepatitis B liver failure (ACLF-HBV) in hepatitis B e antigen (HBeAg)negative patients. METHODS: A total of 109 inpatients with ACLF-HBV were recruited from the Department of Infectious Diseases of the Third Affiliated Hospital, Sun Yat-sen University from October 2007 to October 2010. Entecavir 0.5 mg/d was added to each patient's comprehensive therapeutic regimen. Patients were divided into threegroups according to model for end-stage liver disease (MELD) score: high (≥ 30, 20 males and 4 females, mean age 47.8 ± 13.5 years); intermediate (22-30, 49 males and 5 females, 45.9 ± 12.4 years); and low (≤ 22, 28 males and 3 females, 43.4 ± 9.4 years). Statistical analysis were performed using SPSS 11.0 software. Data with normal distribution were expressed as mean ± SD and comparisons were made with Student's t tests. A value of P < 0.05 was considered statistically significant. Viral loads were related exponentially and logarithmic data were used for analysis. RESULTS: For 24 patients with MELD score ≥ 30, treatment lasted 17.2 ± 16.5 d. Scores before and after treatment were significantly different (35.97 ± 4.87 and 40.48 ± 8.17, respectively, t = -2.762, P = 0.011); HBV DNA load was reduced (4.882 ± 1.847 copies log10/mL to 3.685 ± 1.436 copies log10/mL); and mortality rate was 95.83% (23/24). Of 54 patients with scores of 22-30, treatment lasted for 54.0 ± 43.2 d; scores before and after treatment were 25.87 ± 2.33 and 25.82 ± 13.92, respectively (t = -0.030, P = 0.976); HBV DNA load decreased from 6.308 ± 1.607 to 3.473 ± 2.097 copies log10/mL; and mortality was 51.85% (28/54). Of 31 patients with scores ≤ 22, treatment lasted for 66.1 ± 41.9 d; scores before and after treatment were 18.88 ± 2.44 and 12.39 ± 7.80, respectively, (t = 4.860, P = 0.000); HBV DNA load decreased from 5.841 ± 1.734 to 2.657 ± 1.154 copies log10/mL; and mortality was 3.23% (1/31). CONCLUSION: Fo

关键词： Acute-on-chronic hepatitis B liver failure Hepatitis B e antigen negativity Entecavir Model for end-stage liver disease Mortality

Relationship Between Root Chemical Signals and Grain Quality of Rice

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Agricultural Sciences in China 2007年第1期6卷 47-57页

作者： YANG Jian-chang CHANG Er-hua zhang wen-jie WANG zhi-qin LIU Li-jun Key Laboratory of Crop Genetics and Physiology of Jiangsu Province Yangzhou University Yangzhou 225009 PR. China

This study was designed to elucidate the relationship between root chemical signals and the quality of rice. Various rice genotypes were used. Zeatin （Z）＋ zeatin riboside （ZR）, abscisic acid （ABA）, 1-aminocylopropane -1-carboxylic acid （ACC）, and organic acids in roots during grain filling and the appearance quality, cooking/eating quality were investigated. The correlations among them were analyzed. The results showed that Z ＋ ZR concentrations in the roots at mid- and lategrain-filling stages were significantly and positively correlated with the gel consistency and alkali spreading value （r = 0.72^＊ - 0.90^＊＊）, whereas negatively correlated with the amylose content （r = -0.68^＊ - -0.78^＊＊）. ABA concentrations in roots at mid- grain-filling stage were significantly and negatively correlated with the gel consistency and alkali spreading value （r = -0.90^＊＊-0.91^＊＊）, and positively correlated with the amylose content （r = 0.87^＊＊）. ACC concentrations in root exudates at mid-grain-filling stage were very significantly correlated with the percentage of chalky grains and chalkiness （r = 0.97^＊＊ - 0.98^＊＊）, and those at late-grain-filling stage Were significantly correlated with chalkiness and chalky size （r = 0.69^＊ - 0.96^＊＊）. The more the malic acid and succinic acid exuded from roots for a cultivar, the greater the breakdown values and the smaller the setback values in the starch profile, and the results were reversed for a cultivar with more tartaric acid and citric acid exuded from roots during the grain-filling period. The cultivar with more lactic acid in exudates had smaller gel consistency and alkali spreading values, but had greater amylose content. When roots were treated with exogenous ZR, ABA, and ACC during grain filling, effects of the chemicals on the rice quality were consistent with the relationships of the endogenous hormones （Z ＋ ZR, ABA, and ACC） with the quality indexes. Using rape cake as organic fertilizer can increase the concentrations of mali

关键词： rice root chemical signals appearance quality cooking and eating quality

星形-双梯形接线三相变四相或三相变两相平衡变压器原理研究

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中国电机工程学报 2007年第3期27卷 78-82页

作者：张志文湖南大学电气与信息工程学院湖南省长沙市410082

提出了一种新颖的星形一双梯形接线三相变四相或三相变两相平衡变压器。该变压器采用三相三柱铁心结构,一次侧构成三相系统,采用星形接线,二次侧绕组采用闭合双梯形接线,便于3次谐波电流流通,改善电压波形。2个梯形形状相同,并具有共同... 详细信息

提出了一种新颖的星形一双梯形接线三相变四相或三相变两相平衡变压器。该变压器采用三相三柱铁心结构,一次侧构成三相系统,采用星形接线,二次侧绕组采用闭合双梯形接线,便于3次谐波电流流通,改善电压波形。2个梯形形状相同,并具有共同的底边,其中点为四相系统的公共点。2个梯形的4个顶点构成四相或两相系统。该文阐述了该变压器的基本原理、接线方案和基本方程,导出了一二次侧绕组的电流关系,得出了一次侧中性点电流为零的平衡条件和短路阻抗关系。该变压器铁心及绕组结构简单,材料利用率为100%,特别适合于作为四相输电系统及电气化铁路AT供电方式的主变压器。

关键词：平衡变压器星形-双梯形四相输电系统电气化铁路

A meta-analysis of the long-term effects of chronic pancreatitis surgical treatments： duodenum-preserving pancreatic head resection versus pancreatoduodenectomy

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Chinese Medical Journal 2013年第1期126卷 147-153页

作者： LU wen-ping SHI Qing zhang wen-zhi CAI Shou-wang JIANG Kai DONG Jia-hong Department of Hepatobiliary Surgery Chinese People's LiberationArmy General Hospital Beijing 100853 China Department of Microbiology Peking University Health ScienceCenter Beijing 100191 China

Background Surgery is regarded as the most effective treatment to relieve pain and reduce complications in chronic pancreatitis （CP）. Two major strategies exist： duodenum-preserving pancreatic head resection （DPPHR） and pancreatoduodenectomy （PD）. Many studies suggest that DPPHR offers advantages during surgery and in the short-term; however, the long-term effects have not been thoroughly investigated. We analyzed the long-term outcomes of DPPHR and PD, over follow-up times of at least 1 year, to determine the optimal surgical treatment for CP. Methods We systemically reviewed all CP surgical treatment reports, and only included randomized controlled trials （RCT） comparing DPPHR and PD, excluding unqualified studies using several pre-specified criteria. When multiple publications of a single trial were found, the most comprehensive current data were selected. Characteristics of the study populations and long-term postoperative outcome parameters were collected. The quality of the studies and data was analyzed using RevMan 4.2 software. Results Five trials were qualified for meta-analysis, with 261 participants in total （114 in the DPPHR group and 147 in the PD group）. There were no significant differences in the age, gender, or indications for surgery of each group. At the mean of 5.7-year （1-14 years） follow-up examination, DPPHR and PD resulted in equally effective pain relief, exocrine and endocrine function, and similar mortality rates （P 〉0.05）; however, DPPHR patients had improved global quality of life and weight gain, and reduced diarrhea and fatigue （P 〈0.05）. Conclusion DPPHR and PD result in equal pain relief, mortality, and pancreatic function; however, DPPHR provides superior long-term outcomes.

关键词： chronic pancreatitis surgical treatments long-term postoperative effect meta-analysis

Carbon monoxide inhalation ameliorates conditions of lung grafts from rat brain death donors

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Chinese Medical Journal 2008年第15期121卷 1411-1419页

作者： ZHOU Hua-cheng DING wen-gang CUI Xiao-guang PAN Peng zhang Bing LI wen-zhi Department of Anesthesiology Second Affiliated Hospital of Harbin Medical University Harbin Heilongjiang 150086 China

Background Successful lung transplantation has been limited by the scarcity of donors. Brain death （BD） donors are major source of lung transplantation. Whereas BD process induces acute lung injury and aggravates lung ischemia reperfusion injury. Carbon monoxide （CO） inhalation at 50-500 parts per million （ppm） can ameliorate lung injury in several models. We examined in rats whether CO inhalation in BD donor would show favorable effects on lung grafts. Methods Rats were randomly divided into 4 groups. In sham group, donor rats received insertion of a balloon catheter into the cranial cavity, but the balloon was not inflated. In BD-only group, donor rats were ventilated with 40% oxygen after BD confirmation. In BD＋CO250 and BD＋CO500 groups, donor rats inhaled, after BD confirmation, 250 ppm or 500 ppm CO for 120 minutes prior to lung procurement, and orthotopic lung transplantation was performed. The rats were sacrificed 120 minutes after the lung transplantation by exsanguination, and their blood and lung graft samples were obtained. A total of 8 rats fulfilling the criteria were included in each group. Results The inhalation decreased the severity of lung injury in grafts from BD donors checked by histological examination. CO pretreatment reversed the aggravation of PaO2/FiO2 in recipients from BD donors. The CO inhalation down-regulated pro-inflammatory cytokines （TNF-α, IL-6） along with the increase of anti-inflammatory cytokine （IL-10） in recipient serum, and inhibited the activity of myeloperoxidase in grafts tissue. The inhalation significantly decreased cell apoptosis in lung grafts, inhibiting mRNA and protein expression of intercellular adhesion molecule-1 （ICAM-1） and caspase-3 in lung grafts. Further, the inhalation activated phosphorylation of p38 expression and inhibited phosphorylation of anti-extracellular signal-regulated kinase （ERK） expression in lung grafts. The effects of CO at 500 ppm were greater than those at 250 ppm. Conclusions CO exerts po

关键词： brain death lung transplantation carbon monoxide reperfusion injury肺移植一氧化碳老鼠大脑医学研究手术

Real-world evidence on the efficacy and safety of vonoprazanamoxicillin dual therapy for Helicobacter pylori treatment in elderly patients

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World Journal of Gastroenterology 2025年第1期31卷 68-78页

作者： wen Gao Jing-wen Li Hui Ye Xue-zhi zhang Jian-Xiang Liu Hong Cheng Department of Gastroenterology Peking University First HospitalBeijing 100034China School of Medicine Tsinghua MedicineTsinghua UniversityBeijing 100034China Department of Traditional Chinese Medicine and Integrative Medicine Peking University First HospitalBeijing 100034China

BACKGROUND A dual therapy regimen containing amoxicillin is a common treatment option for the eradication of Helicobacter pylori(***).While substantial research supports the efficacy and safety of vonoprazan and amoxicillin(VA)dual therapy in the general population,there is still a lack of studies specifically focusing on its safety in elderly *** To evaluate efficacy and safety of VA dual therapy as first-line or rescue treatment for *** in elderly *** As a real-world retrospective study,data were collected from elderly patients aged 60 years and above who accepted VA dual therapy(vonoprazan 20 mg twice daily+amoxicillin 1000 mg thrice daily for 14 days)for *** eradication in the Department of Gastroenterology at Peking University First Hospital between June 2020 and January *** status was evaluated by^(13)C-urease breath test 6 weeks after *** adverse events(AEs)during treatment were *** In total,401 cases were ***-one cases were excluded due to loss to follow-up,lack of re-examination,or unwillingness to take *** total of 380 included cases comprised 250 who received VA dual therapy as first-line treatment and 130 who received VA dual therapy as rescue *** was successfully eradicated in 239 cases(95.6%)in the first-line treatment group and 116 cases(89.2%)in the rescue treatment *** overall incidence of AEs was 9.5%for both ***,9.2%of patients experienced an AE in the first-line treatment group and 10.0%in the rescue treatment *** patients discontinued treatment due to AE,with a discontinuation rate of 1.3%.No serious AE *** The VA dual therapy regimen as a first-line treatment and a rescue therapy was effective and safe for elderly patients aged 60 and older.

关键词： Helicobacter pylori Vonoprazan Amoxicillin Dual therapy Elderly

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基于压电陶瓷的结构损伤检测技术

压电与声光 2006年第3期28卷 350-352,356页

作者：张兢徐霞张志文重庆工学院电子信息与自动化学院重庆400050 日本山口大学机械电子研究室

根据压电材料的压电效应,压电陶瓷片(PZT)既可作为传感器又可作为驱动器。将压电陶瓷片粘贴在待测结构的表面,运用压电阻抗技术,对结构中螺栓松动的损伤进行检测分析。实验证明,通过检测压电动态阻抗的变化即可分析出螺栓松动的结构损... 详细信息

根据压电材料的压电效应,压电陶瓷片(PZT)既可作为传感器又可作为驱动器。将压电陶瓷片粘贴在待测结构的表面,运用压电阻抗技术,对结构中螺栓松动的损伤进行检测分析。实验证明,通过检测压电动态阻抗的变化即可分析出螺栓松动的结构损伤情况。基于压电陶瓷的结构损伤检测技术,可以对机械结构进行实时在线损伤检测,它不仅适用于宏观损伤检测,且在高频激励下,对于微小损伤的检测也非常有效。

关键词：结构损伤检测技术压电陶瓷阻抗法导纳螺栓