期刊文献+
共找到7篇文章
< 1 >
每页显示 20 50 100
Determination of the degree 120 time-variable gravity field in the Sichuan-Yunnan region using Slepian functions and terrestrial measurements 被引量:5
1
作者 Jiancheng Han Shi Chen +2 位作者 Zhaohui Chen Hongyan Lu weimin xu 《Earthquake Science》 2021年第3期211-221,共11页
The terrestrial time-variable gravity measurements are characterized by a high signal-to-noise ratio and sensitivity to the sources of mass change in the Earth's crust.These gravity data have many applications,suc... The terrestrial time-variable gravity measurements are characterized by a high signal-to-noise ratio and sensitivity to the sources of mass change in the Earth's crust.These gravity data have many applications,such as surface deformation,groundwater storage changes,and mass migration before and after earthquakes.Based on repeated terrestrial gravity measurements at 198 gravity stations in the Sichuan-Yunnan region(SYR)from 2015 to 2017,we determine a time series of degree 120 gravity fields using the localized spherical harmonic(Slepian)basis functions.Our results show that adopting the first 6 Slepian basis functions is sufficient for effective localized Slepian modeling in the SYR.The differences between two gravity campaigns at the same time of year show an obvious correlation with tectonic features.The degree 120 timevariable gravity models presented in this paper will benefit the study of the regional mass migration inside the crust of the SYR and supplement the existing geophysical models for the China Seismic Experimental Site. 展开更多
关键词 Sichuan-Yunnan region terrestrial gravity measurements time-variable gravity Slepian basis function regional gravity field
下载PDF
Deintercalation of Al from MoAlB by molten salt etching to achieve a Mo_(2)AlB_(2) compound and 2D MoB nanosheets 被引量:1
2
作者 Junji Mou Shibo Li +3 位作者 Weiwei Zhang weimin xu Shukai Fan Guoping Bei 《Journal of Advanced Ceramics》 SCIE EI CAS CSCD 2023年第5期943-953,共11页
Two-dimensional(2D)MoB metal borides(MoB MBene)have attracted much attention due to their fascinating properties and functional applications.So far,work on the synthesis of 2D MoB nanosheets by acid or alkaline etchin... Two-dimensional(2D)MoB metal borides(MoB MBene)have attracted much attention due to their fascinating properties and functional applications.So far,work on the synthesis of 2D MoB nanosheets by acid or alkaline etching of MoAlB has not been very successful.It has been proposed that the 2D MoB MBene may be fabricated by chemical etching of a Mo_(2)AlB_(2) precursor,but further investigations were not performed possibly due to the difficult preparation of the metastable Mo_(2)AlB_(2) compound at high temperatures by solid-state reactions.Here,we report on the successful synthesis of the Mo_(2)AlB_(2) compound and 2D MoB nanosheets by the deintercalation of Al from MoAlB through a ZnCl_(2) molten salt etching approach at relatively low temperatures.The influence of etching temperature,etching time,and starting mixtures on the formation of desirable phases have been investigated.A pure Mo_(2)AlB_(2) compound was synthesized at temperatures below 600℃,while the 2D MoB MBene nanosheets were obtained at 700℃through the molten salt etching of MoAlB.In addition,the present work further confirms that the MoB MBene can be prepared by etching the as-synthesized Mo_(2)AlB_(2) precursor in LiF–HCl solution.Our work demonstrates that the molten salt etching is an effective method to prepare 2D MoB MBene. 展开更多
关键词 two-dimensional(2D)materials Mo_(2)AlB_(2) MoB metal borides(MoB MBene) molten salt etching microstructure
原文传递
某异型钢结构安装方案的研究与分析模拟
3
作者 何剡江 徐卫敏 +1 位作者 余春春 刘彬 《钢结构(中英文)》 2023年第11期20-27,共8页
超高层、异形的钢结构或钢-混组合结构不仅在结构使用阶段受力非常复杂,而且施工过程中结构的变形和受力也特别复杂。该工程为具有特殊形体的钢框架-核心筒结构,存在较多的斜向桁架结构,其顶部与对侧的巨型桁架或核心筒通过水平构件强连... 超高层、异形的钢结构或钢-混组合结构不仅在结构使用阶段受力非常复杂,而且施工过程中结构的变形和受力也特别复杂。该工程为具有特殊形体的钢框架-核心筒结构,存在较多的斜向桁架结构,其顶部与对侧的巨型桁架或核心筒通过水平构件强连接,形成“巨型结构”。在整体结构合龙前后,钢桁架主要构件受力形态差异很大。因此,考虑竖直构件及相应楼盖按常规顺序逐层施工,而斜向钢桁架需先行拼装就位,整体结构形成后再拆除临时支撑,并施加重力荷载。另外,因核心筒与桁架竖向刚度差异较大,两者之间的竖向变形差造成与核心筒相连的构件存在较大的内力。为此,在参考了超高层中伸臂桁架的处理方式后,设计采取“放”的手段,即,与核心筒相邻的构件采取后固接和后安装的做法,以减小竖向变形差的不利影响。为减小施工过程中产生的结构初始变形及内力,同时实现上述“放”的要求,根据受力需要,结合施工上的可行性和经济性,设计拟定了精确模拟和简化模拟两种施工拼装方案,并利用有限元程序SAP 2000进行计算和比较。精确模拟方案是指完全严格按照施工顺序,充分考虑构件拼装过程中的变形和应力,并累计到最终内力计算与变形控制中;简化模拟是指将大部分构件在计算模型中一次成型,将分析的重点聚焦在部分构件后安装及后固接对整体结构和相关构件的影响上。两种方案的差异主要在于,方案A考虑了在施工未完成前,新拼装的钢桁架有一段时间处于悬臂状态,而方案B未考虑这部分的影响。以一榀典型钢桁架为例,具体分析对比两种方案的杆件内力和节点位移等计算结果。由于该工程施工方案的特殊性,设计时对计算模型及参数进行了特殊处理,以实现施工方案中的部分步骤的准确模拟。结果表明,两种模拟方案最终状态的内力及变形无显著差异,变形形态与内力分布类同,多数构件最终状态下内力的变化幅度小于3%。根据分析结果,在保证计算精度的前提下,选择简化模拟方案,以提高分析效率。 展开更多
关键词 特殊建筑形体 悬臂施工 施工全过程精细模拟
原文传递
Techniques for postmortem tenderisation in meat processing:effectiveness,application and possible mechanisms 被引量:3
4
作者 Haibo Shi Fereidoon Shahidi +4 位作者 Jiankang Wang Yan Huang Ye Zou weimin xu Daoying Wang 《Food Production, Processing and Nutrition》 2021年第1期237-262,共26页
Developing efficient and promising tenderising techniques for postmortem meat is a heavily researched topic among meat scientists as consumers are willing to pay more for guaranteed tender meat.However,emerging tender... Developing efficient and promising tenderising techniques for postmortem meat is a heavily researched topic among meat scientists as consumers are willing to pay more for guaranteed tender meat.However,emerging tenderising techniques are not broadly used in the meat industry and,to some degree,are controversial due to lack of theoretical support.Thus,understanding the mechanisms involved in postmortem tenderisation is essential.This article first provides an overview of the relationship of ageing tenderisation and calpain system,as well as proteomics applied to identify protein biomarkers characterizing tenderness.In general,the ageing tenderisation is mediated by multiple biochemical activities,and it can exhibit better palatability and commercial benefit by combining other interventions.The calpain system plays a key role in ageing tenderisation functions by rupturing myofibrils and regulating proteolysis,glycolysis,apoptosis and metabolic modification.Additionally,tenderising techniques from different aspects including exogenous enzymes,chemistry,physics and the combined methods are discussed in depth.Particularly,innovation of home cooking could be recommended to prepare relatively tender meat due to its convenience and ease of operation by consumers.Furthermore,the combined interventions provide better performance in controlled tenderness.Finally,future trends in developing new tenderising techniques,and applied consideration in the meat processing industry are proposed in order to improve meat quality with higher economical value. 展开更多
关键词 Postmortem tenderisation Ageing Emerging technique Combination intervention Functionary mechanism
下载PDF
Cut-off value of ulcerative colitis endoscopic index of severity(UCEIS)score for predicting the need for pouch construction in ulcerative colitis:results of a multicenter study with long-term follow-up 被引量:1
5
作者 weimin xu Weijun Ou +4 位作者 Jihong Fu Yubei Gu Long Cui Jie Zhong Peng Du 《Gastroenterology Report》 SCIE EI 2021年第5期435-442,I0002,共9页
Background Total proctocolectomy with ileal pouch–anal anastomosis(IPAA)was the first choice for the surgical treatment of the ulcerative colitis(UC)patients.The data on the predictive value of the ulcerative colitis... Background Total proctocolectomy with ileal pouch–anal anastomosis(IPAA)was the first choice for the surgical treatment of the ulcerative colitis(UC)patients.The data on the predictive value of the ulcerative colitis endoscopic index of severity(UCEIS)for the need for IPAA in UC patients is scarce.We aimed to establish the UCEIS cut-off value to further analyse whether the UCEIS cut-off was suitable for predicting the need for IPAA in UC patients.Methods The clinical data of UC patients from June 1986 to March 2020 at our institute were retrospectively assessed.The UCEIS scores recorded at the time of the first colonoscopy after hospitalization were used in the study.Receiver operating characteristic curve analysis was performed to determine the UCEIS cut-off value for predicting the need for IPAA.Results A total of 283 UC patients were included in the study,with a median UCEIS of 4.During a median follow-up of 13 years,80 patients(28.3%)received surgery invention,among whom 75(93.8%)underwent IPAA surgery and 5(6.2%)received subtotal colectomy with permanent ostomy.A UCEIS cut-off of 6 had the most significant area under the curve of 0.769 for predicting the need for IPAA(P<0.001),with a sensitivity of 72.0%and specificity of 81.8%.UCEIS≥6 was an independent predictive factor for the need for IPAA(P<0.001)and malignant transformation(P=0.010).Patients with UCEIS≥6 had a significantly shorter IPAA-free survival time than those with UCEIS<6(P<0.001).Conclusions UCEIS≥6 may be a threshold value for decision-making for IPAA and should be recommended for UC patients for reducing the incidence of malignant transformation. 展开更多
关键词 ulcerative colitis endoscopic index of severity ileal pouch-anal anastomosis ulcerative colitis
下载PDF
Thymol ameliorates ammonium toxicity via repressing polyamine oxidase-derived hydrogen peroxide and modulating ammonium transporters in rice root
6
作者 Kai Guo Guangchi An +6 位作者 Ning Wang Bingdong Pang Zhiqi Shi Hongwu Bai Li Zhang Jian Chen weimin xu 《Food Production, Processing and Nutrition》 2021年第1期106-114,共9页
Background:Ammonium is an indispensable nutrient for crop growth,but anoxic conditions or inappropriate fertilizer usage result in the increase in ammonium content in soil.Excessive ammonium causes phytotoxicity.Thymo... Background:Ammonium is an indispensable nutrient for crop growth,but anoxic conditions or inappropriate fertilizer usage result in the increase in ammonium content in soil.Excessive ammonium causes phytotoxicity.Thymol is a kind of natural phenolic compound with anti-microbial properties.However,little is known about the role of thymol in modulating plant physiology.Here we find the novel role of thymol in protecting rice from ammonium toxicity.Results:Thymol remarkably rescued rice seedlings growth from ammonium stress,which may resulted from the attenuation of reactive oxygen species(ROS)accumulation,oxidative injury,and cell death in both shoots and roots.Polyamine oxidase(PAO)metabolizes polyamines to produce ROS in plants in response to stress conditions.Thymol blocked ammonium-induced upregulation of a set of rice PAOs,which contributed to the decrease in ROS content.In rice seedlings upon ammonium stress,thymol downregulate the expression of ammonium transporters(AMT1;1 and AMT1;2);thymol upregulated the expression of calcineurin B-like interacting protein kinase 23(CIPK23)and calcineurin B-like binding protein 1(CBL1),two negative regulators of AMTs.This may help rice avoid ammonium overload in excessive ammonium environment.Correlation analysis indicated that PAOs,AMTs,and CBL1 were the targets of thymol in the detoxification of excessive ammonium.Conclusion:Thymol facilitates rice tolerance against ammonium toxicity by decreasing PAO-derived ROS and modulating ammonium transporters.Such findings may be applicable in the modulation of nutrient acquisition during crop production. 展开更多
关键词 Ammonium toxicity Polyamine oxidase Reactive oxygen species RICE THYMOL
下载PDF
Effect of ultrasound power on extraction kinetic model,and physicochemical and structural characteristics of collagen from chicken lung
7
作者 Ye Zou Heng Yang +5 位作者 Xinxiao Zhang Pingping xu Di Jiang Muhan Zhang weimin xu Daoying Wang 《Food Production, Processing and Nutrition》 2020年第1期10-21,共12页
The effects of ultrasound power on extraction kinetic model,and physicochemical and structural characteristics of collagen from chicken lung were studied.Ultrasound power caused a significant increase in extraction ra... The effects of ultrasound power on extraction kinetic model,and physicochemical and structural characteristics of collagen from chicken lung were studied.Ultrasound power caused a significant increase in extraction rate and equilibrium concentration,with the maximum extraction yield(31.25%)at 150 W.The experimental data were consistent with the predicted ones in this empirical equation,in which the percentage error differences was 0.026–4.159%.Besides,ultrasound treatment did not affect their triple-helical structure.The thermal stability of pepsin-soluble collagen by ultrasound pretreatment(UPSC)was higher,due to the higher imino acid content(20.76%).UPSC also exhibited better solubility and fibril forming capacity.Overall,the kinetic model of UPSC from chicken lung could serve the purpose of obtaining collagen,which displayed a potential alternative source to mammal collagens for application in food,biomaterials and biomedical fields. 展开更多
关键词 Extraction kinetics Chicken lung Pepsin-soluble collagen Ultrasound pretreatment
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部