检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

振动利用对FDM薄板动力学性能的影响研究

振动与冲击 2019年第16期38卷 1-6页

作者：姜世杰 yannick Siyajeu 史银芳孙宁宁赵春雨东北大学机械工程与自动化学院

熔融沉积成型(FDM)是当今迅速发展起来的一种快速成型技术(也称3D打印技术),在一定时间内能够直接打印出具有复杂几何形状的模型或零件。然而,FDM产品在机械性能方面却很难与传统加工方式生产的零件相媲美,成为了制约该项技术发展的重... 详细信息

熔融沉积成型(FDM)是当今迅速发展起来的一种快速成型技术(也称3D打印技术),在一定时间内能够直接打印出具有复杂几何形状的模型或零件。然而,FDM产品在机械性能方面却很难与传统加工方式生产的零件相媲美,成为了制约该项技术发展的重要因素之一。首次提出利用振动提高FDM薄板的动力学特性的新方法:将振动引入FDM过程,建立了振动式FDM 3D打印机;分别制备了引入振动前、后Z和X两个打印方向的试验样件,并进行了相应的锤击法模态试验;对比分析利用振动进行加工的FDM样件和普通样件的试验结果,确定振动利用对FDM薄板动力学性能的影响规律。研究表明,利用振动能够使FDM薄板的固有频率发生改变,有效降低其共振响应,提高模态阻尼比,从而提高FDM薄板的阻尼减振性能。

关键词：熔融沉积成型(FDM) 动力学特性利用振动固有频率共振响应阻尼比

Fatigue in children and adolescents with inflammatory bowel disease

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2019年第5期25卷 632-643页

作者： Els Van de Vijver Ann Van Gils Laura Beckers yannick Van Driessche Nicolette Dorien Moes patrick Ferry van Rheenen Department of paediatric Gastroenterology Hepatology and Nutrition Antwerp University Hospital Department of Anesthesiology Antwerp University Hospital Family Medicine Department of paediatric Gastroenterology Hepatology and Nutrition University Medical Center Groningen

AIM To identify factors other than active disease and anemia that contribute to fatigue in pediatric inflammatory bowel disease(IBD).METHODS We performed an electronic search in Medline and EMBASE from their inception to May 2017 using the search term "fatigue" or the related keywords "physical impairment" and "inflammatory bowel disease" with the filter "child"(age 0-18 years). Cross-sectional and case-control studies were included. We restricted our search to studies published in English. We used the pRISMA checklist and flow diagram. Duplicate articles were manually deleted in End Note. To identify further relevant studies, we checked the reference lists of the selected *** We identified 149 papers, of which 19 were retrieved for full text review. Eleven studies were subsequently excluded because fatigue was not evaluated as an outcome measure. Eight papers focused on the desired topic and were discussed in the final analysis. A lack of uniformity of outcome measures made the pooling of data impossible. In all but one study, questionnaires were used to evaluate fatigue. In the remaining study, an accelerometer was used to measure daily activities, sleeping time and their relationships with fatigue in a more quantifiable manner. Adolescents with IBD are significantly more fatigued than healthy controls. In addition to active disease, increased anxiety or depression and disturbed family relationships were frequently reported predictors of fatigue. Quantitative measurement of physical activity in patients with Crohn's disease showed a reduction in the number of steps per day, and patients with ulcerative colitis had a shorter duration of physical activity during the *** Fatigue in pediatric IBD is related to a combination of biological, functional and behavioral factors, which should all be taken into account when managing fatigue.

关键词： Adolescents Children Fatigue Inflammatory bowel disease physical impairment Sleep

Manganese Dioxide (MnO₂) Gaining by Calcination of Manganese Carbonate (MnCO₃) precipitated from Cobalt Removal Solutions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Applied Sciences 2022年第4期12卷 598-613页

作者： Chungu Mwana Mwamba yannick Michael Kabangu Ngoie Muliangala Mbalaba Francis Kasambay Mutangala Francis Mulaja Tshakatumba Constantin Ilunga Mutombo Gabriel Ilunga Mwanza Israel Department of Metallurgy and Materials Faculty of Polytechnics/University of Lubumbashi Lubumbashi Democratic Republic of the Congo Laboratory of Metallography Faculty of Polytechnics University of Lubumbashi Lubumbashi Democratic Republic of the Congo

precipitation was carried out to obtain manganese carbonate by adding a precipitating agent, sodium carbonate (NaCO3). This was followed by calcination of the manganese carbonate (MnCO3) to obtain manganese dioxide (MnO2). For precipitation tests, a pH ranging from 8 to 10, a time of one to two hours, and a temperature of 25°C and 50°C are the parameters that are considered. The calcination of MnCO3 is carried out under the following conditions: time (1, 2, 3, and 4 hours) and temperature (370°C, 420°C, and 470°C). It should be noted that the temperature range selected for the calcination tests is based on thermodynamic data obtained using the HSC CHEMISTRY software. The results obtained show an effective recovery of manganese at 25°C, in one hour, with a pH of 8.5 with a precipitation yield and manganese content in the precipitate around 98.43% and 24.21%, respectively. During calcination tests, results show an increase in mass loss, for a constant calcination time, as temperature increases. On the other hand, increasing the calcination time at a given temperature causes an increase in mass loss. However, a significant decrease in mass loss is noted at 3 hours of calcination. The highest mass loss is obtained at a temperature of 470°C after 4 hours of calcination.

关键词： Manganese Calcination Temperature Carbonate Manganese Dioxide precipitation

performance Survey of pVC Insulation of LC/Gecamines Electrical Cables Subjected to Ageing and Its Life Span Evaluation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Engineering and Technology 2022年第4期10卷 728-737页

作者： Chungu Mwana Mwamba yannick Michael Kabangu Ngoie Muliangala Mbalaba Francis Kasambay Mutangala Francis Katamea Mwanvua Mavé Twite Kabamba Edmond Lukozi Mufaume Donatien Metallurgy and Materials Department Faculty of Polytechnics University of Lubumbashi Lubumbashi Democratic Republic of the Congo Independent Researcher Faculty of Polytechnics University of Lubumbashi Lubumbashi Democratic Republic of the Congo

Considering the insulators ageing in a mixture of pVC and dye, set following operating conditions and time to ensure proper operation and perfect safety of industrial installations using insulated conductors. The results showed that the insulation carried out by the L.C main office was a good quality (on thermal aspect), because the resistance of the insulation is so high (i.e. 3940 Mega Ohms under normal conditions). The results showed a lifespan of 50 years at a temperature of 40°C (close to ambient temperature), plus minus 33 years at a temperature of 70°C;plus minus 22 years at a temperature of 100°C and 12 years at a temperature of 160°C. Furthermore, information on chemical attack, the results showed that pVC cables have poor resistance to sulfuric acid attack (having a pH of 1.5 and a density of 1.84 g/cmp>3p>). LC/Gecamines is able to produce locally a good quality of electrical cables.

关键词： pVC performance Thermal Ageing Chemical Resistance Cable Life Span

The Management of Lumbosciatic Disc Related Disease at Renaissance University Teaching Hospital of N’Djamena-Chad: About 156 Cases

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Modern Neurosurgery 2023年第1期13卷 25-32页

作者： Goumantar Felicien Toudjingar yannick Canton Kessely Ngaoussandjim Ndom-Assal Olivier Ouambi Donald Djasde Mahouli Fata Vounki Alio Hamit Mahamat Momar Code Ba Department of Neurosurgery La Renaissance University Hospital N’Djamena Chad Department of Neurosurgery Reference Nationale University Hospital Center N’Djamena Chad Department of Neurosurgery Fann University Hospital Center Dakar Senegal

Introduction: Low back disc disease (LSD) is a neurosurgical condition with significant socioeconomic repercussions. The objective of this study was to determine the frequency and report the modalities of management. Methodology: This study on lumbosciatic disc disease was carried out in the neurosurgery department of the University Hospital Center (CHU), la Renaissance in N’Djamena. It covered a period of 12 months (from September 2019 to August 2020). A descriptive and an analytical approach were used. The variables studied were epidemiology, clinic, radiology and therapy. Results: the results showed that LSD represented 14.7% of the reasons for consultation in neurosurgery. The average age was 45.8, and to some extent, it ranges between 18 and 76. Lifting was the main reason behind lumbosciatic disc disease with 35.9% of cases, followed by a sedentary life style which represents 30.8%. Lumbosciatica L5 was noted in 49.4%. Obesity and overweight were significant risk factors (p = 0.02) reported in 59% of cases. Motor and sensory deficits were observed in 14.8% and 17.3% of cases, respectively. CT of the lumbar spine was performed in 91% and MRI in 28.9%. The L4-L5 disc herniation represented 74.3% of cases, with a lateral location in 44.2% and L5 radicular impingement in 30.8%. Conservative treatment was instituted in 87.2% and surgical treatment in 12.8% of cases. Conclusion: LSD is caused by a sedentary lifestyle, physical work and overweight. Surgery deals with complicated cases and cases not responding to conservative treatment.

关键词： Lumbosciatica Herniated Disc Surgical Treatment Conservative Treatment Chad

ESTIMATION OF pARAMETERS IN A CLOSED pYGMY pOpULATION IN CAMEROON

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Annals of Applied Mathematics 2018年第2期34卷 126-137页

作者： yannick Tchaptchie Kouakep David Bekolle University of Ngaoundere ERMIA PO Box 454 Ndang Ngaoundere Cameroon AIMS Cameroon PO Box 608 Limbe Cameroon LYCLAMO/CES-HANGLOA PO Box 46 Ngaoundere Cameroon

Inspired by Kouakep [16], we consider in this note a wellposed model with differential susceptibility and infectivity adding continuous age structure to an ODE model for a ＂Baka＂ pygmy group in the East of Cameroon （Africa）. Assuming a very low contribution of carriers to infection compared to acute infection, we estimate a probability p（a）（to develop symptomatic Hepatitis B state at age a） and acute carriers＇ transmission rate. The value R0 = 2：67 〉 1 of the basic reproduction number estimated from data in the east of Cameroon confirms that HBV is endemic in the Baka pygmy group.

关键词： Hepatitis B parameters estimation Baka pygmy group Cameroon

Increased interleukin-6 is associated with long COVID-19:a systematic review and meta-analysis

在线全文

学校读者我要写书评

暂无评论

Infectious Diseases of poverty 2023年第2期12卷 113-113页

作者： Jing-Xian Yin yannick Luther Agbana Zhi-Shan Sun Si-Wei Fei Han-Qing Zhao Xiao-Nong Zhou Jun-Hu Chen Kokouvi Kassegne School of Global Health Chinese Centre for Tropical Diseases Research Shanghai Jiao Tong University School of Medicine Shanghai People’s Republic of China pan African University Life and Earth Sciences Institute (pAULESI) University of Ibadan Ibadan Nigeria National Institute of parasitic Diseases at Chinese Centre for Disease Control and prevention (Chinese Centre for Tropical Diseases Research) National Health Commission of the People’s Republic of China (NHC) Key Laboratory of Parasite and Vector Biology World Health Organization (WHO) Collaborating Centre for Tropical Diseases National Centre for International Research On Tropical Diseases of the Chinese Ministry of Science and Technology Shanghai People’s Republic of China

Background Coronavirus disease 2019(COVID-19)can involve persistence,sequelae,and other clinical complications that last weeks to months to evolve into long *** studies have suggested that interleukin-6(IL-6)is related to COVID-19;however,the correlation between IL-6 and long COVID-19 is *** designed a systematic review and meta-analysis to assess the relationship between IL-6 levels and long *** Databases were systematically searched for articles with data on long COVID-19 and IL-6 levels published before September 2022.A total of 22 published studies were eligible for inclusion following the pRISMA *** of data was undertaken by using Cochran's Q test and the Higgins I-squared(I2)statistic for ***-effect meta-analyses were conducted to pool the IL-6 levels of long COVID-19 patients and to compare the differences in IL-6 levels among the long COVID-19,healthy,non-postacute sequelae of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection(non-pASC),and acute COVID-19 *** funnel plot and Egger's test were used to assess potential publication *** analysis was used to test the stability of the *** An increase in IL-6 levels was observed after SARS-CoV-2 *** pooled estimate of IL-6 revealed a mean value of 20.92 pg/ml(95%CI=9.30–32.54 pg/ml,I2=100%,pplot showed high levels of IL-6 for long COVID-19 compared with healthy controls(mean difference=9.75 pg/ml,95%CI=5.75–13.75 pg/ml,I2=100%,ppASC category(mean difference=3.32 pg/ml,95%CI=0.22–6.42 pg/ml,I2=88%,p=0.04).The symmetry of the funnel plots was not obvious,and Egger’s test showed that there was no significant small study effect in all *** This study showed that increased IL-6 correlates with long *** an informative revelation suggests IL-6 as a basic determinant to predict long COVID-19 or at least inform

关键词： SARS-CoV-2 COVID-19 Interleukin-6 Long COVID-19 Immune mediator Meta-analysis

patterns of Acute Kidney Injury in a Medical Emergency Department in Sub-Saharan Africa

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Nephrology 2022年第3期12卷 267-275页

作者： Weu Mélanie Tia Mélanie Anastasie Wognin Christ Zahe Reine Marie Koffi Nathanael Mey Kehi Jonathan Kpan Abdul yannick Gonan Ouattara Bourhaima Department of Internal Medicine University Teaching Hospital of Bouaké University Alassane Ouattara of C&ocirc te d’Ivoire Bouaké C&ocirc te d’Ivoire

Background: Acute kidney injury (AKI) is a common in community and a serious outcome in hospital setting. Despite the progress of dialytic and non-dialytic therapeutic means, its mortality remains high. Our objective was to contribute to a better knowledge of how AKI managed in an emergency medical ward in an African country located in the southern part of the Sahara. patients and Methods: We conducted a retrospective study from January 1 to December 31, 2019, conducted at the emergency department of the University Teaching Hospital of Bouake, on cases of AKI. Results: During the study period, we collected 221 cases of AKI out of a total of 1778 files giving a prevalence of 12.4%. The mean age was 54 ± 19 years. A male predominance with a sex ratio of 1.4 was observed. The main past histories were hypertension in 40.4%, cardiac disease in 16.9%, and diabetes in 14.3%. The patients in were classified in 63.8% of cases as stage I, in 22.1% as stage II and in 14.1% as stage III according to the AKIN criteria. AKI was functional in 93.2% of cases. Hemodialysis was indicated in 15 (6.8%) patients, but only 3 (1.4%) underwent it. The mortality rate was 45.2%. Factors associated with mortality were: creatinine level greater than or equal to 30 mg/l, sepsis and impaired vigilance. Conclusion: Acute renal failure was frequent in subjects under 60 years old. Its mechanism of occurrence is functional and therefore it can be prevented by vascular filling. The majority of patients were seen at AKIN Stage I. The outcome was favorable in more than one third of the cases and the mortality rate remains high.

关键词： AKI African Setting High Mortality

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

振动利用对FDM薄板机械性能的影响研究

振动与冲击 2019年第9期38卷 22-26,70页

作者：姜世杰 SIYAJEU yannick 孙宁宁李鹤闻邦椿东北大学机械工程与自动化学院沈阳110819

熔融沉积成型(Fused Deposition Modeling,FDM)是当今迅速发展起来的一种快速成型技术,然而其产品在机械强度方面很难与传统加工方式生产的零件相媲美,成为制约该技术发展的重要因素之一。首次将振动应用于FDM 3D打印过程以期提高制品... 详细信息

熔融沉积成型(Fused Deposition Modeling,FDM)是当今迅速发展起来的一种快速成型技术,然而其产品在机械强度方面很难与传统加工方式生产的零件相媲美,成为制约该技术发展的重要因素之一。首次将振动应用于FDM 3D打印过程以期提高制品的机械性能。首先,将振动引入FDM过程,完成了振动式FDM 3D打印机的改装;然后分别制备了振动引入前、后Z和X两个方向的拉伸试件,并完成了抗拉强度的检测试验;最后,对比分析利用振动加工的FDM试件和普通试件的实验结果,以研究振动对FDM薄板抗拉强度和正交各向异性的影响。试验表明,利用振动能够显著提高FDM薄板Z方向的抗拉强度、弹塑性以及稳定性,并能明显降低FDM薄板的正交各向异性。

关键词：熔融沉积成型振动抗拉强度正交各向异性