期刊文献+
共找到170篇文章
< 1 2 9 >
每页显示 20 50 100
Oxaliplatin-induced neuropathy and colo-rectal cancer patient's quality of life:Practical lessons from a prospective cross-sectional,real-world study
1
作者 Iulian Prutianu Teodora Alexa-Stratulat +11 位作者 Elena Octaviana Cristea Andrei Nicolau Diana Cornelia Moisuc Alina Alexandra Covrig Karina Ivanov Adina Emilia Croitoru Monica Ionela Miron Mihaela Ioana Dinu Anca Viorica Ivanov Mihai Vasile Marinca Iulian Radu Bogdan Gafton 《World Journal of Clinical Cases》 SCIE 2022年第10期3101-3112,共12页
BACKGROUND Colon cancer is one the most common forms of cancer in both sexes.Due to important progress in the field of early detection and effective treatment,colon and rectal cancer survivors currently account for 10... BACKGROUND Colon cancer is one the most common forms of cancer in both sexes.Due to important progress in the field of early detection and effective treatment,colon and rectal cancer survivors currently account for 10%of cancer survivors worldwide.However,the effects of anti-cancer treatments,especially oxaliplatinbased chemotherapy,on the quality of life(QoL)have been less evaluated.Although the incidence of severe chemotherapy-induced neuropathy(CIPN)in clinical studies is below 20%,data from real-world studies is scarce,and CIPN is probably under-reported due to patient selection and the patients’fear that reporting side-effects might lead to treatment cessation.AIM To determine the impact of CIPN on QoL in colorectal cancer patients with a recent history of oxaliplatin-based chemotherapy.METHODS We performed a prospective cross-sectional study in two major Romanian oncology tertiary hospitals—the Regional Institute of Oncology Ia?i(Iasi,Romania)and the Fundeni Clinical Oncology Institute(Bucharest,Romania).All consecutive patients with colon or rectal cancer,undergoing Oxaliplatin-based chemotherapy that consented to enroll in the study,were assessed by means of two questionnaires—the EORTC QQ-CR29(quality of life in colon and rectal cancer patients)and the QLQ-CIPN20(assessment of neuropathy).Several demographical,social,clinical and treatment data were also collected.Statistical analysis was performed by means of SPSS v20.The student t test was used to assess the relationship between the QLQ-CIPN20 and QLQ-CR29 results.Kaplan Meyer-curves were used to report 3-year progression-free survival(PFS)in patients that discontinued chemotherapy vs those that completed the recommended course.RESULTS Of the 267 patients that fulfilled the inclusion criteria in the pre-specified time frame,101(37.8%)agreed to participate in the clinical study.At the time of the enrolment in the study,over 50%of the patients had recently interrupted their oxaliplatin-based chemotherapy,most often due to neuropathy.Almost 85%of the responders reported having tingling or numbness in their fingers or hands,symptoms that were associated with pain in over 20%of the cases.When comparing the scores in the two questionnaires,a statistically significant relationship(P<0.001)was found between the presence of neuropathic symptoms and a decreased quality of life.This correlation was consistent when the patients were stratified by sex,disease stage,comorbidities and the presence of stoma or treatment type,suggesting that neuropathy in itself may be a reason for a decreased quality of life.At the 3 year final assessment,median recurrence-free survival in stageⅢpatients was 26.88 mo.When stratified by completion of chemotherapy,median recurrence freesurvival of stageⅢpatients that completed chemotherapy was 28.27 mo vs 24.33 mo in patients that discontinued chemotherapy due to toxicity,a difference that did not reach statistical significance.CONCLUSION CIPN significantly impacts QoL in colorectal cancer patients.CIPN is also the most frequent reason for treatment discontinuation.Physicians should actively assess for CIPN in order to prevent chronic neuropathy. 展开更多
关键词 Colorectal cancer OXALIPLATIN NEUROPATHY quality of Life Recurrence-free survival cross-sectional study
下载PDF
On-line quality inspection in laser blank welding using ART2 neural network
2
作者 邹媛媛 赵明扬 张雷 《China Welding》 EI CAS 2006年第4期51-54,共4页
Laser blank welding is becoming more and more important in the automotive industry and the quality of the weld is critical for a successful application. A fully automated solution is required to inspect the quality of... Laser blank welding is becoming more and more important in the automotive industry and the quality of the weld is critical for a successful application. A fully automated solution is required to inspect the quality of the blanks. This paper presents a vision inspection system with a CMOS camera which uses ART2 network to inspect the defects on-line to obtain the geometry and the quality of the weld seam. The neural network ART2 has the capability of self-learning fiom the environment. It can distinguish the defects that have been learned before and give new outputs for new defects. So ART2 network is suitable for weld quality inspection in laser blank welding. Additionally, a CO2 laser is used for the blank butt-welding. 展开更多
关键词 quality inspection laser blank welding neural network ART2
下载PDF
Stability evaluation method of large cross-section tunnel considering modification of thickness-span ratio in mechanized operation
3
作者 Junru Zhang Yumeng Liu Bo Yan 《Railway Sciences》 2023年第2期197-210,共14页
Purpose-This study aims to research the large cross-section tunnel stability evaluation method corrected after considering the thickness-span ratio.Design/methodology/approach-First,taking the Liuyuan Tunnel of Huangg... Purpose-This study aims to research the large cross-section tunnel stability evaluation method corrected after considering the thickness-span ratio.Design/methodology/approach-First,taking the Liuyuan Tunnel of Huanggang-Huangmei High-Speed Railway as an example and taking deflection of the third principal stress of the surrounding rock at a vault after tunnel excavation as the criterion,the critical buried depth of the large section tunnel was determined.Then,the strength reduction method was employed to calculate the tunnel safety factor under different rock classes and thickness-span ratios,and mathematical statistics was conducted to identify the relationships of the tunnel safety factor with the thickness-span ratio and the basic quality(BQ)index of the rock for different rock classes.Finally,the influences of thickness-span ratio,groundwater,initial stress of rock and structural attitude factors were considered to obtain the corrected BQ,based on which the stability of a large cross-section tunnel with a depth of more than 100 m during mechanized operation was analyzed.This evaluation method was then applied to Liuyuan Tunnel and Cimushan No.2 Tunnel of Chongqing Urban Expressway for verification.Findings-This study shows that under different rock classes,the tunnel safety factor is a strict power function of the thickness-span ratio,while a linear function of the BQ to some extent.It is more suitable to use the corrected BQ as a quantitative index to evaluate tunnel stability according to the actual conditions of the site.Originality/value-The existing industry standards do not consider the influence of buried depth and span in the evaluation of tunnel stability.The stability evaluation method of large section tunnel considering the correction of overburden span ratio proposed in this paper achieves higher accuracy for the stability evaluation of surrounding rock in a full or large-section mechanized excavation of double line high-speed railway tunnels. 展开更多
关键词 Large cross-section tunnel Mechanized operation Tunnel stability Thickness-span ratio Basic quality index of rock Safety factor DEPTH SPAN
下载PDF
Investigation on quality of life of hospitalized patients in China with digestive system malignancy
4
作者 Kai-Lun Zhang Hong-Xia Xu +14 位作者 Wei Li Jiu-Wei Cui Min Weng Qing-Hua Yao Zeng-Qing Guo Yi Ba Fu-Xiang Zhou Zhi-Kang Chen Su-Yi Li Qing-Chuan Zhao Chun-Ling Zhou Ming Liu Lan Zhou Han-Ping Shi Chun-Hua Song 《Journal of Nutritional Oncology》 2024年第2期53-62,I0001,共11页
Background: The purpose of this study is to evaluate the quality of life(QoL) of hospitalized patients in China suffering from digestive system malignancies and to identify potential risk factors for a decrease in QoL... Background: The purpose of this study is to evaluate the quality of life(QoL) of hospitalized patients in China suffering from digestive system malignancies and to identify potential risk factors for a decrease in QoL.Methods: The European Organization for Research and Treatment Core Quality of Life questionnaire(EORTC QLQ-C30) was applied to evaluate the QoL of 23,519 patients with six digestive malignancies(esophageal cancer, gastric cancer, colorectal cancer, liver cancer, biliary tract cancer, and pancreatic cancer). A t test or analysis of variance was employed to analyze the total EORTC QLQ-C30 scale scores and domain scores of the EORTC QLQ-C30 scale among patients in different subgroups.Results: The average QoL score was 50.4 ± 10.8. The tumor type, age, sex, and TNM stage al had an impact on QoL ratings. Colorectal cancer patients had a better total QoL score(49.3 ± 10.3) and scores in the domains of functioning, with milder symptoms, except for diarrhea. Patients with biliary tract cancer(54.2 ± 12.3) and pancreatic cancer(54.2 ± 12.3) reported a poorer QoL, significant functional impairment, and more pronounced symptoms. Patients with esophageal cancer experienced the most severe financial difficulties(35.2 ± 27.5). Patients aged ≥65 years, women, and those with TNM stage Ⅲ/Ⅳ reported lower QoL. In addition, the disparities in total QoL scores and scores in specific domains were significant among patients with some types of tumors, and based on ethnicity, educational level, occupation, treatment(s) received, and place of residence.Conclusions: There is a need to focus on elderly individuals, those with low educational levels, and patients with progressive malignant tumors and to improve routine disease monitoring and symptom management to enhance the quality of life for patients with malignancies of the digestive system. 展开更多
关键词 quality of life Digestive system malignancy cross-sectional study EORTC QLQ-C30
下载PDF
水质氟化物测定过程影响因素探讨
5
作者 李国玉 丁蓉 蔡长君 《化工设计通讯》 2025年第1期97-99,共3页
氟化物作为水质监测重要指标之一,在水环境监测和评价中具有重要的作用和意义。为准确测定水质氟化物含量,从溶液pH、温度、电极性能、甘汞电极、搅拌速度、仪器响应时间等方面探讨各关键因素对氟化物测定过程的影响,有助于简便、灵敏... 氟化物作为水质监测重要指标之一,在水环境监测和评价中具有重要的作用和意义。为准确测定水质氟化物含量,从溶液pH、温度、电极性能、甘汞电极、搅拌速度、仪器响应时间等方面探讨各关键因素对氟化物测定过程的影响,有助于简便、灵敏、快捷借助电化学法分析样品中氟化物的含量,为环境监测提供一定的理论和实践基础。 展开更多
关键词 氟化物 水质监测 电极 空白值 影响因素
下载PDF
土壤氟化物测定对环境监测结果的影响研究
6
作者 王光培 《黑龙江环境通报》 2025年第1期107-109,共3页
氟化物广泛存在于工业废水、农药、化肥中,会对土壤环境构成严重威胁。土壤氟化物测定的准确性会受多种因素影响,空白值处理是重要影响因素之一。基于此,本文研究土壤氟化物测定中的空白值处理对环境监测结果的影响。研究结果表明,在采... 氟化物广泛存在于工业废水、农药、化肥中,会对土壤环境构成严重威胁。土壤氟化物测定的准确性会受多种因素影响,空白值处理是重要影响因素之一。基于此,本文研究土壤氟化物测定中的空白值处理对环境监测结果的影响。研究结果表明,在采用离子选择电极法测定土壤氟化物时,减去40.25μg的空白值会导致测定结果低于524±30 mg/kg或610±6 mg/kg的真值范围,而不减去空白值的结果 509.5-529.5μg和605.5-609.5μg更接近标准物质的真值。该研究成果能为提高环境监测数据的准确性提供参考。同时证明在氟化物测定过程中,需谨慎进行空白值处理。 展开更多
关键词 土壤氟化物 空白值处理 环境监测 监测质量
下载PDF
A Tailor-made Data Quality Approach for Higher Educational Data 被引量:2
7
作者 Cinzia Daraio Renato Bruni +5 位作者 Giuseppe Catalano Alessandro Daraio Giorgio Matteucci Monica Scannapieco Daniel Wagner-Schuster Benedetto Lepori 《Journal of Data and Information Science》 CSCD 2020年第3期129-160,共32页
Purpose: This paper relates the definition of data quality procedures for knowledge organizations such as Higher Education Institutions. The main purpose is to present the flexible approach developed for monitoring th... Purpose: This paper relates the definition of data quality procedures for knowledge organizations such as Higher Education Institutions. The main purpose is to present the flexible approach developed for monitoring the data quality of the European Tertiary Education Register(ETER) database, illustrating its functioning and highlighting the main challenges that still have to be faced in this domain.Design/methodology/approach: The proposed data quality methodology is based on two kinds of checks, one to assess the consistency of cross-sectional data and the other to evaluate the stability of multiannual data. This methodology has an operational and empirical orientation. This means that the proposed checks do not assume any theoretical distribution for the determination of the threshold parameters that identify potential outliers, inconsistencies, and errors in the data. Findings: We show that the proposed cross-sectional checks and multiannual checks are helpful to identify outliers, extreme observations and to detect ontological inconsistencies not described in the available meta-data. For this reason, they may be a useful complement to integrate the processing of the available information.Research limitations: The coverage of the study is limited to European Higher Education Institutions. The cross-sectional and multiannual checks are not yet completely integrated.Practical implications: The consideration of the quality of the available data and information is important to enhance data quality-aware empirical investigations, highlighting problems, and areas where to invest for improving the coverage and interoperability of data in future data collection initiatives.Originality/value: The data-driven quality checks proposed in this paper may be useful as a reference for building and monitoring the data quality of new databases or of existing databases available for other countries or systems characterized by high heterogeneity and complexity of the units of analysis without relying on pre-specified theoretical distributions. 展开更多
关键词 Knowledge organization Development of data and information services cross-sectional and multiannual quality checks Higher education institutions Information quality
下载PDF
Health-related quality of life evaluated by tumor node metastasis staging system in patients with hepatocellular carcinoma 被引量:11
8
作者 Cui-Xia Qiao Xiao-Feng Zhai +4 位作者 Chang-Quan Ling Qing-Bo Lang Hui-Juan Dong Qun Liu Mou-Duo Li 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第21期2689-2694,共6页
AIM: To investigate and evaluate the change in healthrelated quality of life (HRQoL) by tumor node metastasis (TNM) staging system in patients with hepatocellular carcinoma (HCC). METHODS: A total of 140 patients diag... AIM: To investigate and evaluate the change in healthrelated quality of life (HRQoL) by tumor node metastasis (TNM) staging system in patients with hepatocellular carcinoma (HCC). METHODS: A total of 140 patients diagnosed with HCC between June 2008 and April 2009 in our department were enrolled to this study. One hundred and thirty-five (96.5%) patients had liver cirrhosis secondary to hepatitis B virus (HBV) infection, 73 (54.07%) of them being HBV DNA positive; the other etiologies of liver cirrhosis were alcoholic liver disease (1.4%), hepatitis C (1.4%) or cryptogenic (0.7%). All subjects were fully aware of their diagnosis and provided informed consent. HRQoL was assessed before treatment using the functional assessment of cancer therapy-hepatobiliary (FACT-Hep) questionnaire. Descriptive statistics were used to evaluate demographics and disease-specific characteristics of the patients. One-way analysis of variance and independent samples t tests were used to compare the overall FACT-Hep scores and clinically distinct TNM stages. Scores for all FACT-Hep items were analyzed by frequency analyses. The mean scores obtained from the FACT-Hep in different Child-Pugh classes were also evaluated. RESULTS: The mean FACT-Hep scores were reduced significantly from TNM StageⅠto Stage Ⅱ, Stage ⅢA, Stage ⅢB group (687 ± 39.69 vs 547 ± 42.57 vs 387 ± 51.24 vs 177 ± 71.44, P = 0.001). Regarding the physical and emotional well-being subscales, scores decreased gradually from Stage Ⅰ to Stage ⅢB (P = 0.002 vs Stage Ⅰ; P = 0.032 vs Stage Ⅱ; P = 0.033 vs Stage ⅢA). Mean FACT-Hep scores varied by Child-Pugh class, especially in the subscales of physical well-being, functional well-being and the hepatobiliary cancer (P = 0.001 vs Stage I; P = 0.036 vs Stage Ⅱ; P = 0.032 vs Stage ⅢA). For the social and family well-being subscale, only Stage ⅢB scores were significantly lower as compared with Stage Ⅰ scores (P = 0.035). For the subscales of functional well-being and hepatobiliary cancer, there were significant differences for Stages ⅡΙ, ⅢA and ⅢB (P = 0.002vs StageⅠ). CONCLUSION: HRQoL of patients with HCC worsens gradually with progression of TNM stages. The most impaired subscales of HRQoL, as measured by FACT-Hep, were physical and emotional well-being. 展开更多
关键词 Hepatocellular carcinoma Tumor node metastasis staging Functional assessment of cancer therapy-hepatobiliary Health-related quality of life cross-sectional study
下载PDF
Relationship of Lifestyle Habits with Sleep Quality among Japanese in Their 20s
9
作者 Tomohide Yagyu Kohei Akazawa +4 位作者 Minami Ebihara Junta Ishikawa Koichi Ouchi Koji Kobayashi Kyoko Nakazawa 《Health》 2019年第1期1-8,共8页
The purpose of this study was to analyze the effects of lifestyle on sleep quality in young Japanese adults. A cross-sectional study was conducted on the web. We analyzed 637 eligible subjects (316 men and 321 women) ... The purpose of this study was to analyze the effects of lifestyle on sleep quality in young Japanese adults. A cross-sectional study was conducted on the web. We analyzed 637 eligible subjects (316 men and 321 women) aged 20 - 29 years. Information on diet and individual lifestyle characteristics, including sleep quality, which was assessed using the Pittsburgh Sleep Quality Index Japanese version (PSQI-J). Results were obtained by participants completing an online questionnaire. The participants were divided into two groups based on whether they were students (“student group”) or not (“not student group”). The participants with a PSQI-J global score of 6 or higher were evaluated as low-sleep-quality. Logistic regression analyses were performed to evaluate associations of lifestyle habits with low-sleep-quality. Logistic regression analyses were applied for “student group” and “not student group”. The results showed that days of eating out at dinner (OR: 1.11, CI: 1.00 - 1.22) and skipping dinner (OR: 1.21, CI: 1.05 - 1.42) were significant and independent predictors for low-sleep-quality among the “not student group”. There were no significant and independent predictors for low-sleep-quality among “student group”. Our results suggested that excessive intake by eating out and deficient intake by skipping dinner might lead to a high PSQI-J score. It is necessary for young people to receive education on the importance of cooking their own meals for traditional and daytime eating. The implication of this study lies in the fact that we have analyzed the effects of lifestyle habits on quality of sleep. 展开更多
关键词 SLEEP quality EATING Out SKIPPING MEAL cross-sectionAL Study Pittsburgh SLEEP quality Index
下载PDF
Effect of Eating out on Quality and Quantity of Sleep among Japanese in Their 20s
10
作者 Tomohide Yagyu Kohei Akazawa +2 位作者 Minami Ebihara Junta Ishikawa Ouchi Koichi 《Health》 2018年第9期1261-1269,共9页
The purpose of this study was to analyze the effects of eating out or skipping meals on the quality or quantity of sleep in young Japanese adults. We analyzed 584 eligible subjects (283 men and 301 women) aged 20 - 29... The purpose of this study was to analyze the effects of eating out or skipping meals on the quality or quantity of sleep in young Japanese adults. We analyzed 584 eligible subjects (283 men and 301 women) aged 20 - 29 years. Information on diet and individual lifestyle characteristics, including sleep quality, which was assessed by the Pittsburgh Sleep Quality Index Japanese version (PSQI-J), were obtained by participants completing an online questionnaire. Kendall’s tau coefficient was used to measure the ordinal association between diet and sleep quality. The Mann-Whitney U test was performed to evaluate differences in sleep quality by frequency of eating out and frequency of skipping meals. The results revealed a significant difference in sleep duration and PSQI-J score between people who eat out >2 times a week (“high restaurants group”) and those who do not (“low restaurants group”). Furthermore, whereas the mean sleep duration in the “high restaurants group” was 6.59 hours, the mean sleep duration in the “low restaurants group” was 6.90 hours (p = 0.007). The PSQI-J score was significantly higher in the “high restaurants group” than in the “low restaurants group” (4.91 versus 4.37, p = 0.006). Significant differences were also evident in the test’s component scores: C2, C3, and C7. No significant difference was found in sleep duration and PSQI-J score between the groups in terms of frequency of skipping meals (breakfast, lunch, and dinner). Our results suggested that excessive intake by eating out more than twice a week may lead to short sleep duration and high PSQI-J score. 展开更多
关键词 SLEEP quality Dietary HABITS cross-sectionAL Study Pittsburgh SLEEP quality Index EATING OUT
下载PDF
Approach Based on Response-Surface Method to Optimize Lining of Dies Used in 3D Free-Bending Forming Technology
11
作者 Cheng Cheng Jiaxin Guo +2 位作者 Ali Abd El‑Aty Jie Tao Xunzhong Guo 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2024年第5期307-331,共25页
In three-dimensional free-bending forming(3D-FBF),the tube is not overly constrained,and the plastic deformation behavior and forming quality of the bent tube are significantly affected by the critical structure of th... In three-dimensional free-bending forming(3D-FBF),the tube is not overly constrained,and the plastic deformation behavior and forming quality of the bent tube are significantly affected by the critical structure of the forming die lining.However,the effects of die-lining structural parameters on the tube quality,and a method to determine the combination of die-lining structural parameters is yet to be devised.This study aims to propose a new framework that allows one to understand the effects of various die-lining structural parameters on tube quality and to propose the best combination of die-lining structural parameters.First,finite-element modeling is performed to simulate 3D-FBF and examine the effects of individual die-lining structures on the quality of tube formation.The simulation results show that the deformation-zone length and die gap are positively correlated with the tube-section distortion and wall-thickness variation,whereas it shows an opposite trend with respect to the bending radius.Additionally,the lining chamfer radius of the bending die and the guide lining chamfer radius minimally affect the tube forming quality.Subsequently,the optimal die-lining structure is obtained using the response-surface method.The tube cross-sectional distortion rate reduced from 2.73 to 2.53%after the die lining is optimized.Additionally,the average inner-wall thickness reduced to 1.06 mm,whereas the average outer-wall thickness increased to 0.97 mm.This paper proposes a method for optimizing the forming-die-lining mechanism and for improving the tube forming quality in 3D-FBF. 展开更多
关键词 Die lining Forming quality Response surface method cross-sectional distortion Wall thickness
下载PDF
基于DEFORM-3D的新能源汽车电机定子冲裁成形有限元分析
12
作者 佘冉 文少波 肖庆朋 《机械研究与应用》 2024年第4期133-137,共5页
电机作为新能源汽车的重要组成部件之一,其能量受到广泛的关注。而定子加工质量直接影响到电机的品质,进而影响到新能源汽车的性能。文章以新能源汽车电机高硅钢材料定子为研究对象,在SolidWorks软件中建立模型,运用DEFORM-3D软件对定... 电机作为新能源汽车的重要组成部件之一,其能量受到广泛的关注。而定子加工质量直接影响到电机的品质,进而影响到新能源汽车的性能。文章以新能源汽车电机高硅钢材料定子为研究对象,在SolidWorks软件中建立模型,运用DEFORM-3D软件对定子冲裁过程进行仿真模拟,通过改变冲裁间隙和冲裁速度,分析了冲裁过程中定子应力、应变和材料内部流动速率的变化规律。研究表明,随着冲裁间隙增大,最大冲裁力逐渐减小,且断裂成形存在滞后性;随着冲裁速度的增大,毛刺高度有所增加。研究结果为进一步优化定子冲裁工艺提供了依据,对定子生产制造具有一定指导意义。 展开更多
关键词 电机定子 冲裁 DEFORM-3D 有限元分析 断面质量
下载PDF
冲裁速度对冲压件断面质量的影响 被引量:27
13
作者 赵中华 张猛 韦习成 《塑性工程学报》 CAS CSCD 北大核心 2010年第4期45-49,共5页
研究压力机实际冲压速度对冲裁件断面质量的影响规律,建立物理试验模型和有限元模拟分析模型,确定了Cockcroft-Latham断裂准则和合适的断裂因子,并根据伺服压力机的特性设计了不同的冲压速度。结果表明,对于H1F60CS压力机,速度设置在20... 研究压力机实际冲压速度对冲裁件断面质量的影响规律,建立物理试验模型和有限元模拟分析模型,确定了Cockcroft-Latham断裂准则和合适的断裂因子,并根据伺服压力机的特性设计了不同的冲压速度。结果表明,对于H1F60CS压力机,速度设置在20%左右时,断面质量最好,与实际生产在低速切断时可以提升切断面的品质的经验一致。但当速度再减小时,出现光亮带高度下降,同时毛刺高度增加,说明冲裁速度一味减小,对能提高断面质量并非可行。 展开更多
关键词 普通冲裁 实际冲压速度 断面质量 断裂准则 断裂因子
下载PDF
高速冲裁过程中的韧性断裂和断面质量研究进展 被引量:13
14
作者 陈明和 胡道春 《中国机械工程》 EI CAS CSCD 北大核心 2016年第9期1263-1271,共9页
总结和评述了冲裁过程中均匀塑性流动形成光洁表面以及空穴长大引起断面撕裂的现象,从材料细观损伤角度阐明了高速冲裁韧性断裂机理及材料断裂参数的确定方法;综述了工艺参数对冲裁断面质量的影响规律、冲裁过程中的热效应以及冲裁断面... 总结和评述了冲裁过程中均匀塑性流动形成光洁表面以及空穴长大引起断面撕裂的现象,从材料细观损伤角度阐明了高速冲裁韧性断裂机理及材料断裂参数的确定方法;综述了工艺参数对冲裁断面质量的影响规律、冲裁过程中的热效应以及冲裁断面的微观组织变化等的研究现状;最后对高速冲裁过程中的韧性断裂和断面质量的研究趋势进行了展望。 展开更多
关键词 高速冲裁 韧性断裂 冲裁断面质量 温升效应 绝热剪切带
下载PDF
水质总氮空白实验的分析及改进措施 被引量:11
15
作者 刘燕 申志林 《环境科学与技术》 CAS CSCD 北大核心 2005年第B06期46-48,58,共4页
在总氮的测定过程中,空白测试是必不可少的分析试验,然而,在实际操作应用的过程中,发现空白值经常存在偏高的情况,加大了系统误差。因此,如何降低空白值、保证分析样品的精密度和准确度成为关键之一。从试剂影响、器皿影响、操作过程的... 在总氮的测定过程中,空白测试是必不可少的分析试验,然而,在实际操作应用的过程中,发现空白值经常存在偏高的情况,加大了系统误差。因此,如何降低空白值、保证分析样品的精密度和准确度成为关键之一。从试剂影响、器皿影响、操作过程的影响及环境影响等方面进行全面论述分析,并以实验数据予以验证,在此基础上笔者提出降低空白值的手段和措施,以指导实验室操作实践。 展开更多
关键词 总氮 过硫酸钾 空白实验 水质分析
下载PDF
精冲模具磨损及对制件棱边质量的影响 被引量:3
16
作者 林立峰 王贵成 +2 位作者 樊曙天 张玉新 方代正 《机械设计与制造》 北大核心 2009年第10期243-245,共3页
基于精密冲裁的加工过程,选用DEFORM-2D有限元软件建立出其精密冲裁模型,利用Archard磨损理论对冲裁模具的磨损量等进行了预测,并采用简化刃口与磨损刃口两种形式对精密冲裁进行模拟,系统地揭示出模具特征点上的磨损深度值、制件棱边质... 基于精密冲裁的加工过程,选用DEFORM-2D有限元软件建立出其精密冲裁模型,利用Archard磨损理论对冲裁模具的磨损量等进行了预测,并采用简化刃口与磨损刃口两种形式对精密冲裁进行模拟,系统地揭示出模具特征点上的磨损深度值、制件棱边质量的变化,以及不同刃口磨损状态下板料等效应变、静水应力分布的变化规律。对进一步规范模具更换周期,进而优化模具结构具有重要意义。 展开更多
关键词 精密冲裁 模具 棱边质量 磨损
下载PDF
吹扫捕集-GC/MS法测定水中苯系物质量控制指标研究 被引量:5
17
作者 胡冠九 李娟 +3 位作者 袁力 夏新 王荟 史啸勇 《中国环境监测》 CAS CSCD 北大核心 2011年第B10期30-33,共4页
采用吹扫捕集-气相色谱/质谱法,通过统计全国多家实验室的测定数据和实际样品测试两种方法,对水中苯、甲苯、乙苯、间/对二甲苯、邻二甲苯、苯乙烯和异丙苯8种苯系物的平行样测定相对偏差、空白加标回收率及实际样品加标回收率3个质控... 采用吹扫捕集-气相色谱/质谱法,通过统计全国多家实验室的测定数据和实际样品测试两种方法,对水中苯、甲苯、乙苯、间/对二甲苯、邻二甲苯、苯乙烯和异丙苯8种苯系物的平行样测定相对偏差、空白加标回收率及实际样品加标回收率3个质控指标进行了研究,分别给出每种苯系物的质控指标评价标准,提出其平行样测定相对偏差为6.5%~13.2%;空白加标浓度为0.01~80μg/L时,空白加标回收率的范围为78%~87%;样品测定浓度为未检出~60μg/L、加标浓度在0.2~150μg/L时,实际样品加标回收率范围为74%~122%。 展开更多
关键词 苯系物 质控指标 平行样相对偏差 空白回收率 样品回收率
下载PDF
高速精密级进冲压中的冲裁断面质量实验研究 被引量:7
18
作者 黄珍媛 蔡志兴 +3 位作者 阮锋 郭雷 周驰 肖民 《塑性工程学报》 CAS CSCD 北大核心 2009年第3期9-12,共4页
运用正交实验方法,研究了冲裁间隙、模具表面粗糙度、冲压速度对高速精密级进冲压中的冲裁断面质量的影响,结果显示,模具表面粗糙度对冲裁断面质量的影响最大,模具表面精度越高,冲裁断面质量越好。因此,尽量采用先进的加工设备和加工工... 运用正交实验方法,研究了冲裁间隙、模具表面粗糙度、冲压速度对高速精密级进冲压中的冲裁断面质量的影响,结果显示,模具表面粗糙度对冲裁断面质量的影响最大,模具表面精度越高,冲裁断面质量越好。因此,尽量采用先进的加工设备和加工工艺以获得尽量高的凸、凹模表面加工精度,对于保证高速精密级进冲压中的冲裁断面质量非常重要。 展开更多
关键词 高速精密级进冲压 冲裁断面质量 模具表面粗糙度 正交实验
下载PDF
一种新的冲裁间隙实验模具的设计 被引量:3
19
作者 陈康 田源 +2 位作者 陈元芳 韦正 库美芳 《机械设计与制造》 北大核心 2011年第7期235-237,共3页
冲裁间隙是影响冲裁件质量、模具寿命、冲裁力的重要因素,而冲裁间隙实验又是材料加工专业中的基础实验,在专业课程的学习中具有非常重要的作用。在以往的教学中开设冲裁间隙实验时为了改变冲裁间隙的大小,需要多次更换模具,非常不方便... 冲裁间隙是影响冲裁件质量、模具寿命、冲裁力的重要因素,而冲裁间隙实验又是材料加工专业中的基础实验,在专业课程的学习中具有非常重要的作用。在以往的教学中开设冲裁间隙实验时为了改变冲裁间隙的大小,需要多次更换模具,非常不方便。现开发的是一种新的冲裁间隙实验模具,能实现不拆卸模具的情况下快速更换冲裁凸模,从而为实验提供不同的冲裁间隙值,克服了传统实验中多次装卸模具、调试模具的缺点,节约了实验时间,提高了实验的可靠性和安全性。该模具已经申请了实用新型专利,并获授权。 展开更多
关键词 冲裁间隙 断面质量 实验模具 模具寿命
下载PDF
厚板双侧齿圈压边精冲参数对成形影响规律研究 被引量:2
20
作者 苏春建 王朋 +1 位作者 王清 尹国校 《机械设计与制造》 北大核心 2017年第6期160-163,共4页
在板材精冲加工过程中,加工参数的设定是影响冲裁断面质量的关键。针对厚板精密冲裁件常出现的冲裁件断面质量差的问题,本课题提出双侧齿圈压边的精冲方式,利用DEFORM2D软件建立了8mm AISI-20钢的精冲模型,进行了有限元分析。通过采用... 在板材精冲加工过程中,加工参数的设定是影响冲裁断面质量的关键。针对厚板精密冲裁件常出现的冲裁件断面质量差的问题,本课题提出双侧齿圈压边的精冲方式,利用DEFORM2D软件建立了8mm AISI-20钢的精冲模型,进行了有限元分析。通过采用双侧齿圈压边方式对冲裁成形后的冲裁件断面质量进行模拟,分析齿圈形式、压边力、反压边力及模具圆角等工艺参数对成形过程及冲裁件断面质量的影响规律,通过数值模拟得出在不同工艺参数的条件下厚板精冲变形区内静水压力的变化规律,分析了不同参数条件下冲裁件断面质量与冲裁力之间的关系。实验结果表面,采用V形齿圈,增大压边力、反压边力及凹模圆角半径为0.14mm时对提高精冲件断面质量具有显著作用。 展开更多
关键词 厚板 参数 双侧齿圈压边 模拟 精冲 质量
下载PDF
上一页 1 2 9 下一页 到第
使用帮助 返回顶部