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

高铁路基振动压实机-土耦合系统动力学分析

工程力学 2025年第1期42卷 241-248页

作者：叶阳升尧俊凯蔡德钩魏文彬王柯中国铁道科学研究院铁道建筑研究所北京100081 哈尔滨工业大学土木工程学院哈尔滨150090

压路机连续压实系统根据振动压实过程中振动轮响应评价压实质量,并根据土体压实质量反馈调节压路机工作参数。基于集中参数模型引入塑性弹簧,将压实过程分为弹性、弹塑性、分离三阶段;分别建立三阶段动力学控制方程,依据轮-土相对位移... 详细信息

压路机连续压实系统根据振动压实过程中振动轮响应评价压实质量,并根据土体压实质量反馈调节压路机工作参数。基于集中参数模型引入塑性弹簧,将压实过程分为弹性、弹塑性、分离三阶段;分别建立三阶段动力学控制方程,依据轮-土相对位移与作用力确定各阶段切换条件;采用现场实测数据验证模型可靠性;揭示激振力特性(激振力幅值、激振频率)和土体参数的振动响应规律。结果表明:激振力幅值不变时,振动轮振幅和分离周期随激振频率的增大而减小。激振频率不变时,振动轮振幅和分离周期随着激振频率的增大而增大。当激振力幅值与激振频率不变,振动轮振幅随着土体动剪切模量的提升而降低,土体动剪切模量较小时,土体以塑性变形为主。土体动剪切模量较大时,土体以弹性变形为主,振幅缓慢下降,直至趋于平缓。

关键词：高铁路基路基压实振动压实机土耦合动力学系统

维普期刊数据库博看期刊

Data processing and preliminary results of the Chang'e-3 VIS/NIR Imaging Spectrometer in-situ analysis

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2014年第12期14卷 1578-1594页

作者： bin Liu Chun-Lai Li Guang-Liang Zhang Rui Xu Jian-Jun Liu Xin Ren Xu Tan Xiao-Xia Zhang wei Zuo wei-bin wen Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of Sciences Key Laboratory of Space Active Opto-Electronics Technology Shanghai Institute of TechnicalPhysics Chinese Academy of Sciences

The Chang＇e-3 Visible and Near-infrared Imaging Spectrometer （VNIS） is one of the four payloads on the Yutu rover. After traversing the landing site during the first two lunar days, four different areas are detected, and Level 2A and 2B ra- diance data have been released to the scientific community. The released data have been processed by dark current subtraction, correction for the effect of temperature, radiometric calibration and geometric calibration. We emphasize approaches for re- flectance analysis and mineral identification for in-situ analysis with VNIS. Then the preliminary spectral and mineralogical results from the landing site are derived. After comparing spectral data from VNIS with data collected by the Ma instrument and samples of mare that were returned from the Apollo program, all the reflectance data have been found to have similar absorption features near 1000 nm except lunar sample 71061. In addition, there is also a weak absorption feature between 1750-2400nm on VNIS, but the slopes of VNIS and Ma reflectance at longer wavelengths are lower than data taken from samples of lunar mare. Spectral parameters such as Band Centers and Integrated Band Depth Ratios are used to analyze mineralogical features. The results show that detection points E and N205 are mixtures of high-Ca pyroxene and olivine, and the composition of olivineat point N205 is higher than that at point E, but the compositions of detection points S3 and N203 are mainly olivine-rich. Since there are no obvious absorption features near 1250 nm, plagioclase is not directly identified at the landing site.

关键词： Chang'e-3 -- VNIS -- in-situ analysis -- data processing

Relationship of Retinal Nerve Fiber Layer Thickness and Retinal Vessel Calibers with Cognitive Impairment in the Asymptomatic Polyvascular Abnormalities Population

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2024年第2期37卷 196-203页

作者： WANG Dan Dan WANG An Xin ZHANG Xiao Li wei wen bin WU Shou Ling ZHAO Xing Quan Department of Neurology Beijing Tiantan HospitalCapital Medical UniversityBeijing 100070China China National Clinical Research Center for Neurological Diseases Beijing 100070China Beijing Tongren Eye Center Beijing Key Laboratory of Ophthalmology and Visual ScienceBeijing Tongren HospitalCapital Medical UniversityBeijing 100005China Department of Cardiology Kailuan HospitalTangshan 063001HebeiChina

Objective Cognitive impairment(CI)in older individuals has a high morbidity rate worldwide,with poor diagnostic methods and susceptible population *** study aimed to investigate the relationship between different retinal metrics and CI in a particular population,emphasizing polyvascular *** We collected information from the Asymptomatic Polyvascular Abnormalities Community Study on retinal vessel calibers,retinal nerve fiber layer(RNFL)thickness,and cognitive function of 3,785participants,aged 40 years or *** regression was used to analyze the relationship between retinal metrics and cognitive *** stratified by different vascular statuses were also *** RNFL thickness was significantly thinner in the CI group(odds ratio:0.973,95%confidence interval:0.953–0.994).In the subgroup analysis,the difference still existed in the non-intracranial arterial stenosis,non-extracranial carotid arterial stenosis,and peripheral arterial disease subgroups(P<0.05).Conclusion A thin RNFL is associated with CI,especially in people with non-large vessel *** underlying small vessel change in RNFL and CI should be investigated in the future.

关键词： Retinal nerve fiber layer Cognitive impairment Polyvascular abnormality

Acute Pulmonary Embolism Caused by Local Resection of Choroidal Melanoma

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2016年第6期129卷 743-745页

作者： Yao Huang wen-bin wei Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University Beijing Ophthalmology and Visual Science Key Lab Beijing 100730 China

Uveal melanoma is the most malignancy in adults, with 6-7 cases/million people.^-~j common primary ocular an annual incidence of The choroid is the most common site of involvement occurring in more than 90% *** We conducted a retrospective study for uveal melanoma at Yongren Eye Center from 1997 to 201 I. A total of 682 cases of uveal melanoma were recorded. Among them, 176 （25.8%） cases received local resection surgery. Most of them survived after surgery and had good recovery. However, life-threatening complication of acute pulmonary embolism （APE） occurred in 3 choroidal melanoma patients shortly after surgery. Till now, to the best of our knowledge, there are few reports of severe postsurgical complications of choroidal melanoma.

关键词： Acute Pulmonary Embolism Choroidal Melanoma Controlled Hypotension Local Resection

Local excision of ciliary body tumors： a long-term prospective cohort study in China

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2008年第21期121卷 2152-2156页

作者： wei wen-bin YANG wen-li HU Shi-min LI bin Ophthalmology and Visual Science Key Laboratory Beijing Tongren Eye Center Beijing Tongren HospitaL Capital Medical University Beijing 100730 China

Background Ciliary body tumors are usually difficult to diagnose and treat in early stages. However, treatment of such tumors has trended toward ocular conservation instead of enucleation. Local excision of ciliary body tumors has become effective with the development of the modern vitrectomy, but long-term outcomes are still not clear. Therefore, we reported the outcome of locally excised ciliary body tumors after long-term follow-up. Methods Twenty-two patients （22 eyes）, who had been diagnosed with ciliary body tumors in Beijing Tongren Hospital from January 1996 to June 2001, were enrolled in this prospective cohort study. Localized lamellar sclera-ciliary excisions were performed. In some cases, vitrectomies, scleral graft transplantations, and further excisions of the anterior choroid were performed. Diagnoses were confirmed by histopathologic examination. Patients were followed from five to eleven years after surgery. Their visual acuity, intraocular pressure and local recurrence were recorded with descriptive percentages. Results After surgery, all patients maintained normal eyeball appearances. Six patients maintained circular pupils. The final best corrected visual acuities （BCVA） varied from 0.02-1.00, including 18 patients （81.82%） who had BCVA equal to or better than that before surgery. Fifteen patients （68.18%） had BCVA better than 0.3. Only two patients had intraocular pressure （lOP） of less than 10 mmHg and the other patients maintained normal lOP. Nine cases （40.91%） were given confirmed diagnosis of malignant melanoma, four （18.18%） of melanocytoma, six （27.27%） of nonpigmented ciliary epithelial adenoma, two （9.09%） of neurofibroma, and one （4.55%） of neurinoma. Twenty patients （90.91%） had no recurrence during the follow-up period. In one case melanocytoma recurred seven years after surgery and enucleation was performed. One patient, whose operation removed a malignant melanoma with a diameter of 16 mm, died of hepatic metastasis five years

关键词： ciliary body tumor local excision prospective cohort study

Dilemma in management of ocular medulloepithelioma in a child

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2012年第2期125卷 392-395页

作者： Zhao Hong-shu wei wen-bin Capital Med Univ Beijing Tongren Hosp Beijing Tongren Eye Ctr Beijing 100730 Peoples R China Beijing Ophthalmol & Visual Sci Key Lab Beijing 100730 Peoples R China

Medulloepithelioma,a rare tumor,arises from the epithelium of the medullary *** this article,we present a *** who suffered from secondary glaucoma,initially presumed the primary disease was *** mass was later found,pathologically proved to be *** discuss the patient management with emphasis on the early signs of examination and the role of ultrabiomicroscopy （UBM） in evaluating pediatric secondary glaucoma and in influencing the management of patients with medulloepithelioma.

关键词： medulloepithelioma ciliary body iris pathology

Clinical characteristics and treatment of neurofibroma of the choroid

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2012年第10期125卷 1832-1835页

作者： wei wen-bin JIE Ying MO Jing LI bin Beijing Tongren Eye Center Beijing Tongren HospitalCapital Medical UniversityBeijing 100730China

Background Neurofibroma is a kind of benign neoplasm that derives from nervous tissues. Though this tumor is the most common types in the peripheral nervous system, it is rarely seen in the choroid and easy to be misdiagnosed of choroidal melanoma. The aim of this study was to review the clinical features of neurofibroma of the choroid in the Chinese race. Methods A retrospective case series design was used. Two male and one female patients diagnosed with choroidal neurofibroma in Beijing Tongren Eye Center were included in this study. The clinical histories were abstracted from the patients＇ medical records. Routine eye examinations including visual acuity, intraocular pressure, slit lamp and ophthalmoscope were performed. Auxiliary examinations included fluorescein fundus angiography （FFA）, AB-ultrasound scan, color doppler imaging （CDI）, and magnetic resonance imaging （MRI）. Local resection of the tumors was performed and the specimens underwent pathological examinations. Results The tumors were of yellow-pink color with pigmentation on the surface. CDI showed arterial blood signals in the tumor and MRI showed high-intensity in the Tl-weighted image and a slightly increased intensity in the T2-weighted image. FFA and indocyaninegreen angiography demonstrated the tumors were of hypofluorescence at early stage and hyperfluorescence with prominent leakage at late stage. The pathological examination confirmed the tumors were choroidal neurofibroma. After 5-10-year follow-up, there were no recurrences of the tumors and the retinas were well attached. Conclusions Choroidal neurofibroma is difficult to be diagnosed clinically and pathological confirmation is important. These tumors can be managed conservatively by local resection.

关键词： neurofibroma choroid local resection

Data preprocessing and preliminary results of the Moon-based Ultraviolet Telescope on the CE-3 lander

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2014年第12期14卷 1674-1681页

作者： wei-bin wen Fang Wang Chun-Lai Li Jing Wang Li Cao Jian-Jun Liu Xu Tan Yuan Xiao Qiang Fu Yan Su wei Zuo National Astronomical Observatory Chinese Academy of Sciences Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of Sciences Key Laboratory of Space Astronomy and Technology National Astronomical ObservatoriesChinese Academy of Sciences

The Moon-based Ultraviolet Telescope （MUVT） is one of the payloads on the Chang＇e-3 （CE-3） lunar lander. Because of the advantages of having no at- mospheric disturbances and the slow rotation of the Moon, we can make long-term continuous observations of a series of important celestial objects in the near ultra- violet band （245-340 nm）, and perform a sky survey of selected areas, which can- not be completed on Earth. We can find characteristic changes in celestial brightness with time by analyzing image data from the MUVT, and deduce the radiation mech- anism and physical properties of these celestial objects after comparing with a phys- ical model. In order to explain the scientific purposes of MUVT, this article analyzes the preprocessing of MUVT image data and makes a preliminary evaluation of data quality. The results demonstrate that the methods used for data collection and prepro- cessing are effective, and the Level 2A and 2B image data satisfy the requirements of follow-up scientific researches.

关键词： Chang'e-3 mission -- the Moon-based Ultraviolet Telescope -- data preprocessing -- near ultraviolet band

Quantitative parameter character of choroidal melanoma in contrast-enhanced ultrasound

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2012年第24期125卷 4440-4444页

作者： YANG wen-li wei wen-bin LI Dong-jun a Department of Ophthalmology Beijing Tongren Eye Center Beijing Tongren Hospital Capital Medical University Beijing Ophthalmology & Visual Sciences Key Laboratory Beijing 100730 China

Background Choroidal melanoma is the most common intraocular malignant tumor in adults. It threatens not only the visual function but also the patient＇s life. Therefore, it is important to find a non-traumatic, quantitative and repetitive diagnostic method. This study investigated the value of quantitative analysis of contrast-enhanced ultrasound （CEUS） in the diagnosis of choroidal melanoma. Methods CEUS were performed in 51 cases of choroidal melanoma, which were diagnosed either pathologically or clinically and in 14 cases of choroidal hemangioma. The characteristics of the time-intensity curve of the contrast agent were analyzed. For the quantitative analysis, the following parameters of the contrast agent in the lesion were included： rising time （RT）, time to peak （TTP）, maximum intensity （MI） and the mean transit time （MTT）. Results Choroidal melanoma had the following characteristics on CEUS： Choroidal lesions were completely filled with contrast agent. The typical filling pattern was centripetal, with the peripheral of the choroidal lesion filled with the contrast agent first and then the center of the lesion. In some cases, areas with contrast agent filling defect were obseved in the lesions. The contrast agent filled the lesion slower than the normal eye and orbital tissue but faded faster in the lesion. Quantitative analysis showed that in choroidal melanoma, MI of contrast agent （191.31%±146.90%） was significantly more than that of the normal tissue （100.00%±0.00%）（P 〈0.05） and MTT （（63.56±26.04） seconds） was significanly less than that of the normal tissue （（149.87±182.68）seconds）（P 〈0.05）. TTP （22.80±9.85） was less than that of the normal tissue （（29.57±24.76） seconds） and RT （（18.52±7.09） seconds） was less than that of the normal tissue （（26.45±21.83） seconds）. Both the differences of TTP and RT were not statistically significant though. Logistic regression showed that to predict choroidal melanoma and choroidal hemangioma with MI and MTT, the sensi

关键词： choroidal disease malignant melanoma contrast ultrasound diagnosis