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排序方式: 共有3486条查询结果,搜索用时 125 毫秒
91.
Andrew R. Fallon Di Jin William Phalen G. Gray Fitzsimons Christopher J. Hein 《Coastal management》2017,45(5):360-383
Coastal barrier systems around the world are experiencing higher rates of flooding and shoreline erosion. Property owners on barriers have made significant financial investments in physical protections that shield their nearby properties from these hazards, constituting a type of adaptation to shoreline change. Factors that contribute to adaptation on Plum Island, a developed beach and dune system on the North Shore of Massachusetts, are investigated here. Plum Island experiences patterns of shoreline change that may be representative of many inlet-associated beaches, encompassing an equivocal and dynamically shifting mix of erosion and accretion. In the face of episodic floods and fleeting erosive events, and driven by a combination of strong northeast storms and cycles of erosion and accretion, the value of the average Plum Island residence increases by 34% for properties on the oceanfront where protection comprises a publicly constructed soft structure. Even in the face of state policies that ostensibly discourage physical protection as a means of adaptation, coastal communities face significant political and financial pressures to maintain existing protective structures or to allow contiguous groups of property owners to build new ones through collective action. These factors mitigate against adapting to shoreline change by retreating from the coast, thereby potentially increasing the adverse effects of coastal hazards. 相似文献
92.
针对轨道交通车辆在制造过程中,不锈钢车体表面的钝化膜因机加工、焊接等因素可能遭到破坏,导致不锈钢车体防腐能力下降的情况,详细介绍了不锈钢车体的钝化原理、钝化工艺及钝化效果的检测方法。经过柠檬酸钝化液钝化处理后,可有效去除车体表面游离铁和其他杂质,车体表面颜色均匀一致,提高了不锈钢车体的耐蚀性和美观性。 相似文献
93.
防波堤和航道工程对工程海域潮流场的影响和大风浪条件下航道骤淤是东营港广利港区工程建设中的关键问题。根据搜集的资料和工程区域水文测验数据,对水动力条件、泥沙特征及岸滩演变规律进行分析研究。建立了包含潮汐和泥沙单元的数值模型,用于模拟工程施工对潮流场的影响,并计算了大风浪条件下的骤淤分布规律。结果表明:东营港广利港区具有往复流运动的不正规半日潮流特征。项目建设对口门区域的潮流场影响最大,以大潮为例,涨急、落急流速最大增幅为0.32 m/s和0.16 m/s。10 a一遇风浪条件影响下,口门附近淤强可达0.5 m以上,最大可达到1.02 m。 相似文献
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95.
Hyung Yun Choi Jaeho Shin Chang Jin Oh Jin Ho Bae 《International Journal of Automotive Technology》2017,18(5):851-860
Injury information for vehicle occupants from the body regions of the head, thorax, abdomen, and upper and lower extremities, due to the restraints and interior parts of the vehicle, were extracted from the 2009 ~ 2012 NASS/CDS database. For those cases with high occurrence frequency, a detailed and comprehensive data analysis was performed to find the relationship between the accident, occupant, vehicle, and injury data. A numerical frontal impact sled model with the Hybrid III dummy and the GHBMC human body model was constructed to simulate and identify those injury risks according to NASS/CDS. Among the 5,734 injuries to the aforementioned body regions from frontal crashes are, listed by frequency of occurrence, the lower extremity (27.8 %), upper extremity (21.3 %), thorax (15.1 %), face (10.9 %), spine (8.7 %), head (7.3 %), and abdomen (6.9 %). The main injury sources to the head were the windshield, side structure, and steering wheel. For the thorax and abdomen they were the seat belt and steering wheel. For the lower extremity it was the instrument panel. The main injury patterns for the head were the concussion and the contusion. For the thorax they were vessel laceration and lung contusion. For the abdomen they were laceration and contusion of the organs. For the lower extremity they were bone fracture and ligament rupture. The steering wheel and seat positions were main factors affecting head and thorax injury risks. From the sled impact simulation, high injury risks of the head and thorax were assessed respectively at conditions of steering column tilt down and rear most seat position, which correlated well with the findings from the NASS/CDS data analysis. 相似文献
96.
Taeksu Jung Yongsik Park Young Jin Kim Chongdu Cho 《International Journal of Automotive Technology》2017,18(6):1037-1045
Ensuring engine efficiency is a crucial issue for automotive manufacturers. Several manufacturers focus on reducing the time taken to develop and introduce brand new vehicles to the market. Thus, a synergic approach including various simulations is generally adopted to achieve a development schedule and to reduce the cost of physical tests. This study involved proposing a design process that is very useful in the preliminary development stage through effective support from simulations. This type of simulation-based design process is effective in developing timing chain drives; the use of this process, based on results from multiple trials, showed improvements in performance including low friction and vibration, improved durability, and cost-effective part design when compared to conventional processes. This study proposes an integrated approach to the preliminary design of an automotive timing chain system. The approach involves structural and dynamic analyses. The details of the design process are described by using the case of a virtual engine. This study conducted and summarized a dynamic and structural analysis as well as topological optimization to describe a process to obtain optimal results. The results of this study indicated the following improvements in overall performance factors: 12.1 % improvement in transmission error, 10.1 % reduction in chain tension, 46 % reduction in tensioner arm weight, and 11 % reduction in transversal displacement. 相似文献
97.
目的 评价"SrHPO4/Ca4(PO4)2O/CaHPO4"系掺锶磷灰石骨水泥的生物相容性及其与掺锶量的关系.方法 通过急性全身毒性、热原性、溶血性、体外细胞毒性以及成骨细胞在材料表面的黏附、增殖与表达等实验,检测材料的性能及生物降解潜能.结果 "SrHPO4/Ca4(PO4)2O/CaHPO4"系掺锶磷灰石骨水泥的急性全身毒性、热原性、溶血性、体外细胞毒性均为合格.Sr-CPC的热原性、溶血性以及碱性磷酸酶值与掺锶量呈非线性关系.结论 含锶磷酸钙骨水泥体外细胞生物相容性良好,是安全的新型骨组织工程支架材料. 相似文献
98.
三甲益肝冲剂对实验性肝纤维化大鼠脂质过氧化的影响 总被引:2,自引:0,他引:2
目的观察三甲益肝冲剂对大鼠肝纤维化的作用并探讨与抗脂质过氧化有关的作用机制。方法雄性SD大鼠40只,随机分为模型组、复方丹参组、三甲益肝冲剂组和正常组。以二甲基亚硝胺(DMN)腹腔注射诱导大鼠肝纤维化模型,复方丹参组造模同时给予复方丹参灌胃,三甲益肝冲剂组造模同时给予三甲益肝冲剂灌胃,共4周。4周后处死大鼠取肝组织标本,光镜观察肝组织的病理变化,放射免疫法测定血清丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性。结果与正常组比较,模型组肝组织Masson染色胶原纤维面积和血清MDA含量显著增加(P<0.05),而血清SOD活性明显下降(P<0.05);与模型组比较,三甲益肝冲剂组Masson染色胶原纤维面积和血清MDA含量显著下降(P<0.05),而SOD活性明显升高(P<0.05)。Masson染色胶原纤维面积和血清MDA含量表达呈正相关关系(r=0.435,P<0.05),与SOD活性呈负相关关系(r=-0.358,P<0.05)。结论三甲益肝冲剂具有良好的抗实验性大鼠肝纤维化作用,其主要作用机制与抗肝脏脂质过氧化损伤有关。 相似文献
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100.