检索结果-南通市图书馆

Improved thermal resistance network model of motorized spindle system considering temperature variation of cooling system

在线全文

学校读者我要写书评

暂无评论

Advances in Manufacturing 2018年第4期6卷 384-400页

作者： Yang Liu Ya-Xin Ma qing-yu meng Xi-Cheng Xin Shuai-Shuai Ming School of Mechanical Engineering and Automation. Northeastern University Shenyang 110819 Liaoning People's Republic of China

In the motorized spindle system of a computer numerical control (CNC) machine tool, internal heat sources are formed during high-speed rotation;these cause thermal errors and affect the machining accuracy. To address this problem, in this study, a thermal resistance network model of the motorized spindle system is established based on the heat transfer theory. The heat balance equations of the critical thermal nodes are established according to this model with Kirchhoffs law. Then, they are solved using the Newmark-β method to obtain the temperature of each main component, and steady thermal analysis and transient thermal analysis of the motorized spindle system are performed. In order to obtain accurate thermal characteristics of the spindle system, the thermal conduction resistance of each component and the thermalconvection resistance between the cooling system and the components of the spindle system are accurately obtained considering the effect of the heat exchanger on the temperature of the coolant in the cooling system. Simultaneously, high-precision magnetic temperature sensors are used to detect the temperature variation of the spindle in the CNC machining center at different rotational speeds. The experimental results demonstrate that the thermal resistance network model can predict the temperature field distribution in the spindle system with reasonable accuracy. In addition, the influences of the rotational speed and cooling conditions on the temperature increase of the main components of the spindle system are analyzed. Finally, a few recommendations are provided to improve the thermal performance of the spindle system under different operational conditions.

关键词： Motorized spindle system Thermal resistance network model Temperature field Cooling system

The process of retinal vascularization in retinopathy of prematurity after ranibizumab treatment in China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2019年第7期12卷 1146-1150页

作者： qing-yu meng Yong Cheng Ming-Wei Zhao Jian-Hong Liang Department of Ophthalmology & Clinical Center of Optometry Peking University People's Hospital Beijing 100044 China Eye Diseases and Optometry Institute Peking University People's Hospital Beijing 100044 China Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases Beijing 100044 China College of Optometry Peking University Health Science Center Beijing 100191 China

AIM: To explore the process of retinal vascularization and risk factors for retinopathy of prematurity(ROP) treated with intravitreal ranibizumab(IVR) as ***: Infants with type 1 ROP who received IVR as primary treatment from August 2014 to October 2016 at Peking University People’s Hospital’s Ophthalmology Department were included in the study. All eyes received 0.25 mg ranibizumab at initial treatment. Retinal vascularization was evaluated clinically. Potential risk factors were also recorded and ***: Retinal vascularization was completed in 126 eyes(62.7%), and retinal vascularization terminated in zone II and zone III with 16 eyes(7.9%) and 44 eyes(21.9%), respectively, after more than 1-year follow-up. In multivariate regression analysis, lower birth weight(BW), severity of ROP and repeated injections were found to be risk factors for peripheral avascular area(P<0.05). CONCLUSION: In our retrospective study, 29.8% of the ROP eyes treated with ranibizumab have peripheral avascular area at the last follow-up. Lighter BW and the severity of ROP are risk factors. Furthermore, repeated injections also increase the risk of retinal peripheral avascular area remaining in ROP patients.

关键词： retinal vascularization retinopathy of prematurity ranibizumab avascular retinal area

Dynamically switchable porphyrin-based molecular tweezer for on-off fullerene recognition

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2024年第6期35卷 283-287页

作者： Zhimin Sun Xin-Hui Guo yue Zhao qing-yu meng Li-Juan Xing He-Lue Sun College of Chemistry and Materials Science Hebei Key Laboratory of Organic Functional MoleculesHebei Normal UniversityShijiazhuang 050024China

Herein,a novel molecular tweezer based on 2,2'-bipyridine-bridged porphyrin subunits was constructed for efficient fullerenes *** syn conformation of the molecule,which was obtained by Zn(Ⅱ)coordination,gives rise to a proper cavity to interact with fullerene guests to form a stable 1:1 complex in toluene *** exhibits distinct binding selectivity towards C_(60)over C_(70).Moreover,the fullerene recognition capacity can be adequately suppressed by importing H_(2)PO_(4)^(-)to competitively capture Zn(Ⅱ)along with syn-anti conformational ***,the molecular tweezer regenerated to bind the fullerene by introducing the Ca^(2+)into the ***,the association-disassociation process can be switched reversibly and repeatedly.

关键词： Molecular tweezer Fullerene recognition Supramolecular chemistry Conformation conversion Coordination

Negative Charge Management to Make Fragile Bonds Less Fragile toward Electrons for Robust Organic Optoelectronic Materials

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2022年第1期4卷 331-343页

作者： Rui Wang qing-yu meng Yi-Lei Wang Juan Qiao Key Lab of Organic Optoelectronics and Molecular Engineering of the Ministry of Education Department of ChemistryTsinghua UniversityBeijing 100084 Center for Flexible Electronics Technology Tsinghua UniversityBeijing 100084

The operational stability of organic(opto)electronic devices largely depends on the intrinsic stability of organic materials on *** organic light-emitting diode(OLED)materials,a key parameter of their intrinsic stability is the bond-dissociation energy of the most fragile bond(BDE_(f)).Although rarely involved,many OLED molecules have the lowest BDE_(f) in anionic states[BDE_(f)(−)∼1.6–2.5 eV],which could be a fatal short-slab for device ***,we separated BDE_(f)(−)from other parameters and confirmed the clear relationship between BDE_(f)(−),intrinsic material stability and device *** on thermodynamic principles,we developed a general and effective strategy to greatly improve BDE_(f)(−)by introducing a negative charge manager within the *** manager must combine an electron-withdrawing group(EWG)with a delocalizing structure,so that it can firmly confine the negative charge and hinder the charge redistribution toward fragile ***,the use of this manager can substantially promote BDE_(f)(−)by∼1 eV for various fragile bonds and outperform the effect reported from solely employing EWGs or delocalizing *** effect was verified in typical phosphine-oxide and carbazole derivatives and backed up by newly designed molecules with multiple fragile *** strategy provides a new way to transform vulnerable building blocks into robust organic(opto)electronic materials and devices.

关键词： organic anions bond-dissociation energy chemical degradation intrinsic stability organic light-emitting diodes

A Comparative Study on the Bathing Cultures and the Spread of Plague Between China and the West-Taking the Spread of the Black Death in China and Europe in the 14th Century as an Example

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Literature and Art Studies 2023年第5期13卷 377-382页

作者： yu meng-qing School of Translation Studies Shandong UniversityWeihai 264209China

An unprecedented catastrophe shrouded over the Chinese Empire ruled by the yuan Dynasty and Medieval Europe-the Black Death during the 14th century with rapid spread,widespread impact,serious damage to property,and substantial deaths and *** the aftermath of the Black Death,lifestyle changes were made and more sensible bathing habits *** feudal China,Bathing Culture had variously adapted to each dynasty;while its existence in the West was heavily influenced by religion and other *** the post-pandemic era,this paper is dedicated to exploring the possible relevance of Bathing Cultures to the Black Death,and to conducting a comparative study of the plague spread in yuan and Europe and its impact on ethnic Bathing Cultures,reckoning to present informative information to regular prevention and control of the following pandemics.

关键词： bathing culture the Black Death pandemic transmission prevention control

Choroidal thickness,myopia,and myopia control interventions in children:a Meta-analysis and systemic review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2023年第3期16卷 453-464页

作者： qing-yu meng Ze-Qun Miao Shu-Ting Liang Xi Wu Le-Jin Wang Ming-Wei Zhao Li-Li Guo Department of Ophthalmology&Clinical Centre of Optometry Peking University People’s HospitalBeijing 100044China Eye Disease and Optometry Institute Peking University People’s HospitalBeijing 100044China Beijing Key Laboratory of Diagnosis and Therapy of Retinal and Choroid Diseases Beijing 100044China College of Optometry Peking University Health Science CenterBeijing 100044China

AIM:To investigate changes of choroidal thickness(ChT) in children with myopia and the effect of current myopia control interventions on ***:Major literature databases were searched for studies relevant to myopia in *** studies used swept-source optical coherence tomography(SS-OCT) or enhanced depth imaging optical coherence tomography(EDI-OCT) to measure the ChT *** weighted mean difference(WMD) and 95% confidence interval(CI) were pooled to evaluate ChT in myopia ***:A total of 11 eligible articles,including 1693 myopic and 1132 non-myopic eyes,were included in the first *** sub-foveal choroidal thickness(SFCT;WMD=-40.06,95%CI,-59.36 to-20.75,P<0.001) and ChT at other sectors were significantly thinner in myopic eyes compared with the non-myopic *** Meta-analysis revealed that the ChT decreased horizontally from the temporal sector toward the nasal sector in the pediatric myopia *** 11 studies reporting the effect of myopia control interventions were included in the second Meta-analysis for the relationship between myopia control treatments and *** significantly increased after orthokeratology(OK) treatment and OK combined with 0.01% atropine(OKA) treatment(WMD=19.47,95%CI,15.96 to 22.98,P<0.001;WMD=21.81,95%CI,12.92 to 29.70,P<0.001,respectively).The forest plots showed that SFCT changed little in myopic children receiving 0.01% atropine(P=0.30).Furthermore,the Meta-analysis showed that OK treatment had a stronger effect on the value of SFCT in myopic children as compared with 0.01% atropine(WMD=9.86;95%CI,-0.21 to 19.93,P=0.05).There is no difference between the treatment with OK and OKA treatment in ChT in myopic children(P=0.37).CONCLUSION:The ChT in myopic eyes is thinner than that in non-myopic eyes in pediatric *** control interventions including OK and OKA lead to ChT thickening,but other treatments such as 0.01% atropine did not show an increase in ChT.

关键词： choroidal thickness myopia orthokeratology atropine children Meta-analysis

Surgical procedure and prognosis of hilar cholangiocarcinoma

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2004年第3期3卷 453-457页

作者： Bin Yi, Bai-He Zhang, Yong-Jie Zhang, Xiao-qing Jiang, Bao-Hua Zhang,Wen-Long yu, qing-Bao Chen and meng-Chao Wu Department of Biliary Surgery, Eastern HepatobiliarySurgery Hospital, Shanghai 200438 , China Department of Biliary Surgery Eastern Hepatobiliary Surgery Hospital Shanghai 200438 China. billyyi@***

BACKGROUND: Hilar cholangiocarcinoma has a low radi-cal resection rate and a poor long-term survival rate. In re-cent years, its prognosis has been improved with advance-ment of preoperative diagnostic techniques and surgicaltechniques. The aim of this study was to evaluate the prog-nostic factors of hilar cholangiocarcinoma and the relationsof surgical procedure to the prognosis of the ***: A retrospective cohort study was done in 198patients with hilar cholangiocarcinoma (117 men and 81women, aged from 27 to 81 years) , who had been admit-ted to this hospital from December 1997 to December *** symptoms were jaundice (94.5%), pruritus (56.6%)and abdominal pain (33.8%). Bismuth-Corlette classifica-tion showed type in 14 patients, type in 19, type in12, type in 15, type in 112, and unclassifiable typein 26. 144 patients underwent laparotomy and others re-ceived bile drainage endoscopically (including endoscopicretrograde biliary drainage (ERBD) or endoscopic metalbiliary endoprosthesis (EMBE) in 21 patients, endoscopicnose-biliary drainage (ENBD) in 31 or percutaneous trans-hepatic cholangiodrainage in 2. 120 patients (83.3%) re-ceived tumor resection including radical resection in 59 pa-tients (41.0%). Twenty-three patients underwent paunchedbiliary exploration and ***: Cox' s regression model analysis showed thatoccupation, preoperative total serum bilirubin level, opera-tive procedure and postoperative adjuvant radiation weresignificantly related to postoperative survival rate in con-trast to gender, age, choledocholithiasis, hepatitis, preope-rative serum CA19-9 level, Bismuth-Corlette type, his-topathologic grading and postoperative chemotherapy. Thesurvival of patients in groups of biliary drainage, palliativeresection and radical resection differed statistically and pro-longed in a descending order. No statistical difference wasfound between ERBD or EMBE group and palliative resec-tion group. So was between ERBD or EMBE group

关键词： cholangiocarcinoma/surgery prognosis cholangiopancreatography endoscopic retrograde

Identification of antimalarial targets of chloroquine by a combined deconvolution strategy of ABPP and MS-CETSA

在线全文

学校读者我要写书评

暂无评论

Military Medical Research 2023年第1期10卷 64-77页

作者： Peng Gao Yan-qing Liu Wei Xiao Fei Xia Jia-yun Chen Li-Wei Gu Fan Yang Liu-Hai Zheng Jun-Zhe Zhang Qian Zhang Zhi-Jie Li yu-qing meng Yong-Ping Zhu Huan Tang Qiao-Li Shi Qiu-Yan Guo Ying Zhang Cheng-Chao Xu Ling-yun Dai Ji-Gang Wang Artemisinin Research Center Institute of Chinese Materia MedicaChina Academy of Chinese Medical SciencesBeijing 100700China Department of Traditional Chinese Medicine Southern Medical UniversityGuangzhou 510515China Department of Geriatrics the Second Clinical Medical College of Jinan Universitythe First Affiliated Hospital of Southern University of Science and TechnologyShenzhen People’s HospitalShenzhen 518020GuangdongChina Institute of Molecular and Cell Biology Agency for ScienceTechnology and Research(A*STAR)Singapore 138673Singapore Department of Biological Sciences National University of SingaporeSinga‑pore 117543Singapore

Background: Malaria is a devastating infectious disease that disproportionally threatens hundreds of millions of people in developing countries. In the history of anti-malaria campaign, chloroquine(CQ) has played an indispensable role, however, its mechanism of action(MoA) is not fully ***: We used the principle of photo-affinity labeling and click chemistry-based functionalization in the design of a CQ probe and developed a combined deconvolution strategy of activity-based protein profiling(ABPP) and mass spectrometry-coupled cellular thermal shift assay(MS-CETSA) that identified the protein targets of CQ in an unbiased manner in this study. The interactions between CQ and these identified potential protein hits were confirmed by biophysical and enzymatic ***: We developed a novel clickable, photo-affinity chloroquine analog probe(CQP) which retains the antimalarial activity in the nanomole range, and identified a total of 40 proteins that specifically interacted and photocrosslinked with CQP which was inhibited in the presence of excess CQ. Using MS-CETSA, we identified 83 candidate interacting proteins out of a total of 3375 measured parasite proteins. At the same time, we identified 8 proteins as the most potential hits which were commonly identified by both ***: We found that CQ could disrupt glycolysis and energy metabolism of malarial parasites through direct binding with some of the key enzymes, a new mechanism that is different from its well-known inhibitory effect of hemozoin formation. This is the first report of identifying CQ antimalarial targets by a parallel usage of labeled(ABPP)and label-free(MS-CETSA) methods.

关键词： Chloroquine Antimalaria Activity-based protein profiling(ABPP) Cellular thermal shift assay(CETSA) Quantitative proteomics

火电厂DCS系统主控制室人机界面仿真评价研究

在线全文

学校读者我要写书评

暂无评论

系统仿真学报 2009年第16期21卷 5251-5255页

作者：许青孟庆鑫颜声远哈尔滨工程大学机电工程学院哈尔滨150001

提出了火电厂DCS系统主控制室人机界面功能仿真评价方法,开发了主控制室功能仿真模型与人机界面评价软件。该方法可在主控制室投入运行之前对人机界面的设计与操纵员主观期望一致性进行仿真评价,减少由于人因设计不良而导致误读、误判... 详细信息

提出了火电厂DCS系统主控制室人机界面功能仿真评价方法,开发了主控制室功能仿真模型与人机界面评价软件。该方法可在主控制室投入运行之前对人机界面的设计与操纵员主观期望一致性进行仿真评价,减少由于人因设计不良而导致误读、误判和误操作的发生。构造了主控制室OM画面评价指标体系,运用层次分析法计算了OM画面评价指标的权值。采用操纵员作为评价主体对OM画面进行了功能仿真评价。评价结果表明,提出的火电厂DCS系统主控制室人机界面仿真评价方法能及时发现人机界面的设计缺陷,可用于工程应用前的人因设计评价。

关键词：功能仿真评价 DCS系统主控制室人机界面评价指标