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多片簧悬架簧上振动特性的研究
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作者 刘守银 周福庚 钱友军 《农业装备与车辆工程》 2010年第4期16-19,共4页
在参阅国内外簧上振动文献和大量试验的基础上,本文对多片簧上共振的现象、主观评价、发生机理以及试验数据分析进行了阐述,对簧上共振提出改善措施并进行验证和对比评价,最后简单阐述改善簧上共振的意义。
关键词 多片簧 悬架 簧上质量 上共振 平顺性
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一类双曲向量场的光滑线性化 被引量:2
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作者 任志华 《北京大学学报(自然科学版)》 CAS CSCD 北大核心 2004年第1期1-4,共4页
讨论了一类向量场X(x) =Ax +…在双曲奇点附近的光滑线性化及有限阶光滑线性化问题。
关键词 共振 上共振 共振 向量场 线性化
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XMQ6116客车某车速大位移振动的试验分析与改进 被引量:2
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作者 张攀登 《客车技术与研究》 2010年第5期50-52,共3页
XMQ6116客车车速稳定在40~45km/h时整个车身出现有规律的、大位移的振动。经测试发现,该振动是上下方向的、频率3~4Hz,接近人体上下方向的共振频率,驾驶员和乘客反应强烈。通过计算得知,共振时轮胎的激励频率与共振频率吻合,证明激励... XMQ6116客车车速稳定在40~45km/h时整个车身出现有规律的、大位移的振动。经测试发现,该振动是上下方向的、频率3~4Hz,接近人体上下方向的共振频率,驾驶员和乘客反应强烈。通过计算得知,共振时轮胎的激励频率与共振频率吻合,证明激励来自路面,改变轮胎的半径可以调节共振的车速;减小悬架刚度可以减小车身上下振动的刚体模态。 展开更多
关键词 车速共振 上共振 试验 分析 改进
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驱动桥桥壳承载能力试验研究 被引量:1
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作者 谢凡 黄志亮 +1 位作者 张云飞 邓习树 《时代汽车》 2021年第11期160-161,共2页
某型工程车辆,在可靠性试验过程中,驱动桥桥壳若为冲焊结构,会经常从推力杆支座焊缝位置开裂,影响试验效率。对桥壳进行试验研究发现平衡悬架结构在搓衣板路上存在低频“拍击”附加力,并会引起簧上共振,使推力杆座焊缝位置的应力异常增... 某型工程车辆,在可靠性试验过程中,驱动桥桥壳若为冲焊结构,会经常从推力杆支座焊缝位置开裂,影响试验效率。对桥壳进行试验研究发现平衡悬架结构在搓衣板路上存在低频“拍击”附加力,并会引起簧上共振,使推力杆座焊缝位置的应力异常增大,容易产生裂纹。 展开更多
关键词 驱动桥 平衡悬架 低频附加力 上共振
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MAGNETIC RESONANCE IMAGING CHARACTERISTICS AND SURGICAL RESULTS OF ADRENOCORTICOTROPIN-SECRETING PITUITARY ADENOMAS 被引量:9
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作者 Bing Xing Kan Deng Zu-yuan Ren Chang-bao Su Ren-zhi Wang Yi Yang Wen-bin Ma Yong-ning Li 《Chinese Medical Sciences Journal》 CAS CSCD 2008年第1期44-48,共5页
Objective To evaluate magnetic resonance imaging (MRI) characteristics and surgical results of adrenocorticotropin (ACTH) -secreting pituitary adenomas. Methods MRI characteristics and relationship between MRI po... Objective To evaluate magnetic resonance imaging (MRI) characteristics and surgical results of adrenocorticotropin (ACTH) -secreting pituitary adenomas. Methods MRI characteristics and relationship between MRI positive rate and surgical results of 266 patients with pathologically confn'med Cushing's disease were analyzed retrospectively. All patients underwent thin-section sagittal and coronal scans of the pituitary gland before and after administration of gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) on a 1. 5 Tesla MR/scanner, and dynamic enhanced MR/was performed in 39 patients. All patients underwent transsphenoidal adenomectomy. Endocrinological examinations and assessments were performed. Results Preoperative MR/revealed normal results in 41 ( 15.4% ) cases, microadenoma in 179 (67. 3% ), macroadenoma in 42 ( 15.8% ), and huge adenoma in 4 ( 1.5% ). Pituitary apoplexy was found in 13 (4.9%) cases. Positive rate of ACTH-secreting adenomas was 84.6% (225/266) on MR/scans, and that of small microadenomas was 87.2% (34/39) on dynamic enhanced MRI scans. Preoperative endocrinological tests of 199 cases supported the diagnosis of typical Cushing's disease, while the other 67 cases had atypical endocrinological results. The endocrinological cure rate, remission rate, and inefficacy rate were 85.7%, 7.9%, and 6. 4%, respectively. There was no difference in the initial endocrinological cure rate between the patients with positive and normal MRI results (90% vs. 87. 8%, P =0. 904). Conclusions Enhanced coronal pituitary MR/ is helpful for preoperative localization of ACTH-secreting pituitary microadenoma. Dynamic enhanced MR/may improve detection rate of microadenoma. There is no marked difference in the surgical results for patients with preoperative MR/results indicating presence or absence of microadenoma. 展开更多
关键词 adrenocorticotropin-secreting pituitary adenoma magnetic resonance imaging DIAGNOSIS TREATMENT
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Case Report:Subglottic adenoid cystic carcinoma mistaken for asthma 被引量:1
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作者 Hua-lin WANG Lin XU Fu-jun LI 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2009年第9期707-710,共4页
Adenoid cystic carcinoma rarely occurs within the subglottic larynx. In this study, a case of subglottic adenoid cystic carcinoma was reported. A 54 year-old Chinese woman developed a sudden onset of chest distress an... Adenoid cystic carcinoma rarely occurs within the subglottic larynx. In this study, a case of subglottic adenoid cystic carcinoma was reported. A 54 year-old Chinese woman developed a sudden onset of chest distress and cough worsening after physical exertion, and was diagnosed with, and treated as, bronchial asthma. Regular anti-asthmatic therapy did not improve the symptoms. Until a sudden dyspnea, a cervicothoracic computerized tomography (CT) revealed that her upper airway was obstructed by a laryngeal tumor. The patient was diagnosed with a subglottic adenoid cystic carcinoma and treated with complete surgical excision and adjuvant radiation therapy. Follow-up endoscopy and laryngeal magnetic resonance imaging (MR1) at six months showed no recurrence of the tumor. The diagnosis of subglottic adenoid cystic carcinoma should be considered in patients who are characterized by dyspnea, cough, and stridor, but do not respond to regular anti-asthmatic therapy. 展开更多
关键词 Subglottic adenoid cystic carcinoma LARYNX ASTHMA
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