期刊文献+
共找到86篇文章
< 1 2 5 >
每页显示 20 50 100
Petrological and geochemical characteristics of mafic rocks from the Neoproterozoic Sugetbrak Formation in the northwestern Tarim Block,China 被引量:1
1
作者 Hong-zhe Xie Xiang-kun Zhu +2 位作者 xun wang Yuan He Wei-bing Shen 《China Geology》 CAS CSCD 2023年第1期85-99,共15页
The Neoproterozoic Sugetbrak Formation in the Aksu area,which is located at the northwest margin of Tarim Block,comprises mafic rocks and provides key records of the evolution of the Rodinia supercontinent.However,the... The Neoproterozoic Sugetbrak Formation in the Aksu area,which is located at the northwest margin of Tarim Block,comprises mafic rocks and provides key records of the evolution of the Rodinia supercontinent.However,the genetic relationship among these mafic rocks exposed in different geographical sections are still unclear.In this study,the petrology,geochemistry,and Sr-Nd-Pb isotope geochemistry of the mafic rocks exposed in the Aksu-Wushi and Yuermeinark areas have been studied in some detail along three sections.The authors found that the mafic rocks in these three typical sections were mainly composed of pyroxene and plagioclase,containing a small amount of Fe-Ti oxides and with typical diabasic textures.All the mafic rocks in this region also showed similar geochemical compositions.They were characterised by high TiO_(2)contents(1.47%–3.59%)and low MgO(3.52%–7.88%),K_(2)O(0.12%–1.21%).Large ionic lithophile elements(LILEs)(Rb,Sr,and Cs)were significantly depleted.Meanwhile,high field strength elements(HFSEs)were relatively enriched.In the samples,light rare earth elements(LREEs)were enriched,while heavy rare earth elements(HREEs)were depleted.Based on the Zr/Nb,Nb/Y,and Zr/TiO_(2)ratios,the Aksu mafic rocks belong to a series of sub-alkaline and alkaline transitional rocks.The mafic rocks along the three typical sections showed similar initial values of^(87)Sr/^(86)Sr(I_(Sr))(0.7052–0.7097)and ε_(Nd)(t)(–0.70 to–5.35),while the Pb isotopic compositions with^(206)Pb/^(204)Pb,^(207)Pb/^(204)Pb and^(208)Pb/^(204)Pb values of 16.908–17.982,15.487–15.721,37.276–38.603,respectively.Most of the samples plot into the area near EM-Ⅰ,indicating that the magma of the mafic rocks might have derived from a relatively enriched mantle with some crustal materials involved.The geochemical element characteristics of most samples showed typical OIB-type geochemical characteristics indicating that the source region had received metasomatism of recycled materials.Combining with the regional geological background and geochemical data,we inferred that the mafic rocks of the Sugetbrak Formation in the Aksu area were formed in an intraplate rift environment.Summarily,based on our study,the mafic rocks of the Sugetbrak Formation in the Aksu area were derived from a common enriched mantle source,and they were product of a magmatic event during the rift development period caused by the breakup of the Rodinia supercontinent. 展开更多
关键词 Mafic rocks Sugetbrak Formation Rodinia supercotinent NEOPROTEROZOIC Sr-Nd-Pb isotopes Mantle plume Geological survey engineering Tarim Block Xinjiang
下载PDF
Rupture process of the January 8, 2022, Menyuan M 6.9 earthquake
2
作者 xun wang Cuiping Zhao 《Earthquake Research Advances》 CSCD 2023年第4期27-32,共6页
After the occurrence of destructively strong earthquakes, rapid acquisition of the source rupture process can provide important reference information for post-earthquake disaster relief and aftershock trend determinat... After the occurrence of destructively strong earthquakes, rapid acquisition of the source rupture process can provide important reference information for post-earthquake disaster relief and aftershock trend determination.An M 6.9 earthquake occurred in Menyuan County, Qinghai Province on January 8, 2022. The epicenter is located in the seismic gap in the middle section of the Haiyuan fault belt. Such a typical strong earthquake was taken as an example to investigate the rupture process of strong earthquakes. Three days after the earthquake, the InSAR(Interferometric Synthetic Aperture Radar) coseismic deformation field was obtained by Sentinel radar, indicating that the surface ruptured obviously. The southern block of the earthquake faces towards the satellite about 95 cm along the LOS(line of sight) direction, and the northern block is away from the satellite by ~ 74 cm, consistent with the characteristic of left-lateral strike-slip motion. In this study, InSAR coseismic deformation data and farfield waveform data were used to jointly invert the earthquake rupture process, and a four-segment finite fault model was constructed by referring to the surface deformation. The inversion results show that the focal depth of the Menyuan earthquake is about 7 km, and the strike of the seismogenic fault is 89.0°, 104.0°, 119.0°and 131.0°from west to east, respectively. It is a high-dip left-lateral strike-slip earthquake event lasting about 14 s. The rupture propagation mode is a bilateral extension. The maximum slip along the fault is about 380 cm, and the seismic moment magnitude is 6.7. The surface rupture length is about 24 km, which is consistent with that measured in the field survey. The detailed seismic source model can provide basic data for the aftershock trend determination and seismic risk analysis of the adjacent active faults. 展开更多
关键词 Menyuan earthquake Rupture process INSAR Joint inversion
下载PDF
Research on AGV task path planning based on improved A^(*) algorithm
3
作者 Xianwei wang Jiajia LU +2 位作者 Fuyang KE xun wang Wei wang 《Virtual Reality & Intelligent Hardware》 2023年第3期249-265,共17页
Background Automatic guided vehicles(AGVs)have developed rapidly in recent years and have been used in several fields,including intelligent transportation,cargo assembly,military testing,and others.A key issue in thes... Background Automatic guided vehicles(AGVs)have developed rapidly in recent years and have been used in several fields,including intelligent transportation,cargo assembly,military testing,and others.A key issue in these applications is path planning.Global path planning results based on known environmental information are used as the ideal path for AGVs combined with local path planning to achieve safe and rapid arrival at the destination.Using the global planning method,the ideal path should meet the requirements of as few turns as possible,a short planning time,and continuous path curvature.Methods We propose a global path-planning method based on an improved A^(*)algorithm.The robustness of the algorithm was verified by simulation experiments in typical multiobstacle and indoor scenarios.To improve the efficiency of the path-finding time,we increase the heuristic information weight of the target location and avoid invalid cost calculations of the obstacle areas in the dynamic programming process.Subsequently,the optimality of the number of turns in the path is ensured based on the turning node backtracking optimization method.Because the final global path needs to satisfy the AGV kinematic constraints and curvature continuity condition,we adopt a curve smoothing scheme and select the optimal result that meets the constraints.Conclusions Simulation results show that the improved algorithm proposed in this study outperforms the traditional method and can help AGVs improve the efficiency of task execution by planning a path with low complexity and smoothness.Additionally,this scheme provides a new solution for global path planning of unmanned vehicles. 展开更多
关键词 Autonomous guided vehicle(AGV) Map modeling Global path planning Improved A^(*)algorithm Path optimization Bezier curves
下载PDF
我国资源衰退型地区产业转型发展的问题与对策 被引量:2
4
作者 王勋 纪文铮 《工信财经科技》 2021年第1期13-19,共7页
我国资源衰退型地区经济结构转型与产业升级仍面临十分严峻的挑战。资源衰退地区转型困难的根本原因在于,在资源开采开发过程中,未能主动以自身优势为基础逐渐建立起接续替代产业。进而,扭曲的市场结构对民营企业、专业人才等形成了显... 我国资源衰退型地区经济结构转型与产业升级仍面临十分严峻的挑战。资源衰退地区转型困难的根本原因在于,在资源开采开发过程中,未能主动以自身优势为基础逐渐建立起接续替代产业。进而,扭曲的市场结构对民营企业、专业人才等形成了显著的挤占或挤出效应,导致市场机制缺乏包容性,经济缺乏吸引力和竞争力。因此,在充分发挥市场机制作用的基础上,中央和地方政府应相互配合,积极引导资源衰退地区以自身优势为基础发展接续替代产业,在国企债转股和混合所有制改革、完善软硬基础设施建设、设立绿色金融创新试点、支持民营企业创新创业等关键领域和重要环节给予必要的政策、资金支持,着力提升市场机制的包容性,推进资源衰退地区转型发展。 展开更多
关键词 资源产业衰退型地区 市场包容性 转型发展
下载PDF
情绪与情绪调节策略对知晓感(Feeling-of-Knowing)判断的影响
5
作者 王勋 田婷婷 张振新 《心理学进展》 2014年第7期963-974,共12页
本研究通过两个实验来研究情绪和情绪调节策略对知晓感判断的影响。在实验一中,通过让被试观看影片片段,激发相应的情绪状态,然后对不同情绪的词对做知晓感判断;在实验二中,通过观看影片诱发被试的负性情绪,然后采用不同情绪调节策略对... 本研究通过两个实验来研究情绪和情绪调节策略对知晓感判断的影响。在实验一中,通过让被试观看影片片段,激发相应的情绪状态,然后对不同情绪的词对做知晓感判断;在实验二中,通过观看影片诱发被试的负性情绪,然后采用不同情绪调节策略对被试的情绪状态进行调节并对不同情绪词对做知晓感判断。结果表明:1) 情绪状态和词对的情绪性质对FOK的判断等级和准确性存在影响,表现为在中性状态下,中性词对的判断等级和准确性均高于情绪词对;2) 情绪调节策略对FOK的判断等级产生影响,评价忽视策略和表情宣泄策略条件下被试的FOK判断值显著高于评价重视和表达抑制;3) 情绪调节策略对FOK判断准确性也存在影响,评价重视和评价忽视两种调节策略下被试的FOK判断准确性显著高于表情宣泄和表情抑制策略。 展开更多
关键词 元认知 知晓感 情绪 情绪调节
下载PDF
BUC-21/N-K2Ti4O9复合材料光催化去除Cr(Ⅵ):组成上的细微差异导致性能上的巨大差异 被引量:5
6
作者 王恂 李玉璇 +4 位作者 衣晓虹 赵晨 王鹏 邓积光 王崇臣 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 2021年第2期259-270,共12页
近年来,金属-有机骨架(MOFs)作为一种多相光催化剂因其合成方法多样、活性位点可调等优点被越来越多地应用于光催化还原Cr(Ⅵ)、还原CO2和降解有机污染物等领域.但多数MOFs被其电导率低、电子与空穴的快速复合以及仅在紫外光下激发下才... 近年来,金属-有机骨架(MOFs)作为一种多相光催化剂因其合成方法多样、活性位点可调等优点被越来越多地应用于光催化还原Cr(Ⅵ)、还原CO2和降解有机污染物等领域.但多数MOFs被其电导率低、电子与空穴的快速复合以及仅在紫外光下激发下才能表现出光催化活性等缺点限制了其进一步应用.为此,与g-C3N4、Ag2CO3、TiO2、Bi24O31Br10等半导体、电活性聚合物(PANI)、导体(RGO)、贵金属纳米颗粒(Ag,Pd)等构建复合物是增强MOFs光催化性能的一个有效策略.本文采用简单的机械球磨法,以BUC-21和N-K2Ti4O9为前驱体快速制备了一系列BUC-21/N-K2Ti4O9复合材料(记为B1NX,其中X=0.2,0.5,1,2,3和4,代表N-K2Ti4O9在复合物中的比例).采用粉末X射线衍射(PXRD)、傅里叶变换红外光谱(FTIR)、扫描电镜(SEM)、透射电镜(TEM)、高倍透射电镜(HRTEM)、紫外-可见漫反射(UV-Vis DRS)和X射线光电子能谱(XPS)等技术对UAC-X复合物的形貌和结构进行了表征.研究了B1NX在紫外光和白光照射下光催化还原六价铬(Cr(Ⅵ))的性能.探究了不同pH(pH=2-8)、不同小分子有机酸(柠檬酸、酒石酸和草酸)及共存离子(自来水和湖水中的离子)对光催化还原Cr(Ⅵ)的影响.结果表明,PXRD谱图显示B1NX的衍射峰位置分别与BUC-21和N-K2Ti4O9峰位置完全吻合.SEM、TEM、EDS和HRTEM图片证明在B1NX复合物中BUC-21附着在N-K2Ti4O9表面.在紫外光照射下40 min后,B1N0.5的光催化活性最高,还原效率达到100.0%,且还原速率是BUC-21的1.42倍.而在白光照射下,随着N-K2Ti4O9含量的增加,复合物的光催化活性先增后减.最佳比例B1N3可在100 min时还原99%的Cr(Ⅵ),远远优于对Cr(Ⅵ)几乎无还原能力的BUC-21和N-K2Ti4O9.这是因为N-K2Ti4O9含量的增加不仅有利于电荷的转移,也有利于白光的利用.在紫外光和白光照射下,随着溶液pH值从2提高到8,还原效率逐渐降低.这是因为在酸性条件下H+浓度高有利于Cr(Ⅵ)还原为Cr(Ⅲ),而当pH>6时,Cr^3+与OH-形成Cr(OH)3沉淀附着在催化剂表面,影响对光的吸收,降低了光催化效率.当反应体系中加入草酸、柠檬酸和酒石酸等小分子有机酸时,光催化速率得到显著提高,这是由于小分子链烃有机物容易捕捉光生空穴.共存离子实验表明,虽然湖水和自来水中的共存离子对B1N0.5和B1N3的还原性能稍有抑制,但当反应时间延长时,这种影响可忽略不计.表观量子效率实验证明B1NX还原Cr(Ⅵ)是光诱导过程.光致发光分析、时间分辨光致发光分析、电化学分析、电子自旋共振(ESR)和活性物质捕获实验显示,B1N0.5和B1N3中BUC-21最低未占轨道(LUMO)上的光生电子转移至N-K2Ti4O9导带,提高了光生电子和空穴的分离效率,最终增强了光催化还原Cr(Ⅵ)的活性.N-K2Ti4O9的引入也使得BUC-21的光吸收区域拓展至白光,实现了其实际应用的潜力.同时,B1N0.5在紫外光照射下和B1N3在白光照射下经过5次光催化循环实验后其还原Cr(Ⅵ)效率仍然可达99%,且PXRD谱图、SEM和TEM图像未见明显变化,表明其具有稳定性和重复利用性.综上,BUC-21/N-K2Ti4O9是一种具有应用前景的高效复合型光催化剂. 展开更多
关键词 BUC-21 N-K2Ti4O9 光催化 六价铬 紫外光和白光
下载PDF
Berberine Attenuates Cigarette Smoke Extract-induced Airway Inflammation in Mice:Involvement of TGF-β1/Smads Signaling Pathway 被引量:6
7
作者 Wen wang Gan ZHA +3 位作者 Jin-jing ZOU xun wang Chun-nian LI Xiao-jun WU 《Current Medical Science》 SCIE CAS 2019年第5期748-753,共6页
Although several studies confirmed that berberine may attenuate airway inflammation in mice with chronic obstructive pulmonary disease(COPD),its underlying mechanisms were not clear until now.We aimed to establish an ... Although several studies confirmed that berberine may attenuate airway inflammation in mice with chronic obstructive pulmonary disease(COPD),its underlying mechanisms were not clear until now.We aimed to establish an experiment mouse model for COPD and to investigate the effects of berberine on airway inflammation and its possible mechanism in COPD model mice induced by cigarette smoke extract(CSE).Twenty SPF C57BL/6 mice were randomly divided into PBS control group,COPD model group,low-dose berberine group and high-dose berberine group,5 mice in each group.The neutrophils and macrophages were examined by Wright's staining.The levels of inflammatory cytokines TNF-α and IL-6 in bronchoalveolar lavage fluid(BALF)were detennined by enzyme-linked immunosorbent assay.The expression levels of TGF-β1,Smad2 and Smad3 mRNA and proteins in lung tissues were respectively detected by quantitative real-time polymerase chain reaction and Western blotting.It was found that CSE increased the number of inflammation cells in BALF,elevated lung inflammation scores,and enhanced the TGF-β1/Smads signaling activity in mice.High-dose berberine restrained the alterations in the COPD mice induced by CSE.It was concluded that high-dose berberine ameliorated CSE-induced airway inflammation in COPD mice.TGF-β1/Smads signaling pathway might be involved in the mechanism.These findings suggested a therapeutic potential of high-dose berberine on the CSE-induced airway inflammation. 展开更多
关键词 BERBERINE CIGARETTE SMOKE extract chronic OBSTRUCTIVE pulmonary disease TGF-β1/Smads signaling pathway
下载PDF
附睾小体功能蛋白及sRNA研究进展 被引量:5
8
作者 肖娟 王讯 +3 位作者 罗毅 李晓开 李学伟 苗龙 《遗传》 CAS CSCD 北大核心 2018年第3期197-206,共10页
精液质量是反映男性生殖健康最基本和最重要的指标。哺乳动物的精子需在附睾中经历一系列复杂的结构与功能的变化才能成熟并具有潜在受精能力。精子成熟是由大量转录因子、激素等信号分子协同调控的复杂生理过程。近年来越来越多的证据... 精液质量是反映男性生殖健康最基本和最重要的指标。哺乳动物的精子需在附睾中经历一系列复杂的结构与功能的变化才能成熟并具有潜在受精能力。精子成熟是由大量转录因子、激素等信号分子协同调控的复杂生理过程。近年来越来越多的证据表明附睾小体(epididymosomes)中的功能蛋白和s RNAs(small RNAs)可参与调节精子成熟及受精等过程。本文主要综述了附睾小体中功能蛋白及两类主要的s RNAs(t RNAs和mi RNAs)的生物学作用,以期为男性不育等疾病的治疗提供一定的理论指导和新的治疗思路。 展开更多
关键词 精液 EXOSOME 附睾小体 蛋白质 MIRNA tsRNA
下载PDF
Benefits of multidisciplinary collaborative care team-based nursing services in treating pressure injury wounds in cerebral infarction patients 被引量:7
9
作者 You-Hua Gu xun wang Si-Si Sun 《World Journal of Clinical Cases》 SCIE 2022年第1期43-50,共8页
BACKGROUND Cerebral infarction patients need to be bedridden for long periods of time often resulting in pressure injuries,which may represent a serious threat to patients'life and health.An effective nursing prog... BACKGROUND Cerebral infarction patients need to be bedridden for long periods of time often resulting in pressure injuries,which may represent a serious threat to patients'life and health.An effective nursing program should be adopted for timely intervention in patients with pressure wounds.AIM To explore the value of nursing services based on a multidisciplinary collaborative treatment team in patients with pressure injury wounds following cerebral infarction.METHODS Patients with cerebral infarction pressure injury wounds in our hospital from December 2016 to January 2021 were selected and divided into one study group and one control group based on the simple random number table method.The control group was treated with conventional nursing care(CNC),and the study group was treated with care services based on multidisciplinary collaborative care(MDCC).The Pressure Ulcer Scale for Healing(PUSH),healing effect,Self-Perceived Burden Score(SPBS),and satisfaction with the intervention were calculated before and after 2 and 4 wk of intervention in both groups.RESULTS Sixty-two patients were enrolled,and 31 patients were assigned to each group.The results of the interventions were as follows:(1)There was no significant difference between the PUSH scores of the MDCC group(11.19±2.46)and CNC group(12.01±2.79)before the intervention(P>0.05),and the PUSH scores were lower after 2 and 4 wk of intervention in the MDCC group(6.63±1.97 and 3.11±1.04)than in the CNC group(8.78±2.13 and 4.96±1.35 points)(P<0.05);(2)The rate of wound healing in the MDCC group(96.77%)was higher than that in the CNC group(80.65%)(P<0.05);(3)There was no significant difference between the SPBS scores of emotional factors(21.15±3.11),economic factors(9.88±2.15),and physical factors(8.19±2.23)in the two groups before the intervention.The scores of emotional factors(13.51±1.88),economic factors(6.38±1.44),and physical factors(5.37±1.08)were lower in the MDCC group than in the CNC group(16.89±2.05,7.99±1.68 and 7.06±1.19)after 4 wk of intervention(P<0.05);and(4)Satisfaction with the intervention was higher in the MDCC group(93.55%)than in the CNC group(74.19%)(P<0.05).CONCLUSION Interventions for patients with cerebral infarction pressure wounds based on an MDCC treatment team can effectively reduce patients'self-perceived burden,improve pressure wound conditions,facilitate wound healing,and increase patient satisfaction with the intervention. 展开更多
关键词 Multidisciplinary collaborative treatment team Pressure injury wounds from cerebral infarction Pressure Ulcer Scale for Healing score Self-Perceived Burden Score Healing effect
下载PDF
The SSA-BP-based potential threat prediction for aerial target considering commander emotion 被引量:4
10
作者 xun wang Jin Liu +1 位作者 Tao Hou Chao Pan 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第11期2097-2106,共10页
The target's threat prediction is an essential procedure for the situation analysis in an aerial defense system.However,the traditional threat prediction methods mostly ignore the effect of commander's emotion... The target's threat prediction is an essential procedure for the situation analysis in an aerial defense system.However,the traditional threat prediction methods mostly ignore the effect of commander's emotion.They only predict a target's present threat from the target's features itself,which leads to their poor ability in a complex situation.To aerial targets,this paper proposes a method for its potential threat prediction considering commander emotion(PTP-CE)that uses the Bi-directional LSTM(BiLSTM)network and the backpropagation neural network(BP)optimized by the sparrow search algorithm(SSA).Furthermore,we use the BiLSTM to predict the target's future state from real-time series data,and then adopt the SSA-BP to combine the target's state with the commander's emotion to establish a threat prediction model.Therefore,the target's potential threat level can be obtained by this threat prediction model from the predicted future state and the recognized emotion.The experimental results show that the PTP-CE is efficient for aerial target's state prediction and threat prediction,regardless of commander's emotional effect. 展开更多
关键词 Aerial targets Emotional factors Potential threat prediction BiLSTM Sparrow search algorithm Neural network
下载PDF
Potentially fatal electrolyte imbalance caused by severe hydrofluoric acid burns combined with inhalation injury: A case report 被引量:3
11
作者 He Fang Guang-Yi wang +2 位作者 xun wang Fang He Jian-Dong Su 《World Journal of Clinical Cases》 SCIE 2019年第20期3341-3346,共6页
BACKGROUND Hydrofluoric acid(HF)is one of the most common causes of chemical burns.HF burns can cause wounds that deepen and progress aggressively.As a result,HF burns are often severe even if they involve a small are... BACKGROUND Hydrofluoric acid(HF)is one of the most common causes of chemical burns.HF burns can cause wounds that deepen and progress aggressively.As a result,HF burns are often severe even if they involve a small area of the skin.Published cases of HF burns have mostly reported small HF burn areas.Few cases of HF inhalation injury have been reported to date.CASE SUMMARY A 24-year-old man suffered from extensive hydrofluoric acid burns covering 60%of the total body surface area(TBSA),including deep second degree burns on 47%and third degree burns on 13%of the TBSA,after he fell into a pickling pool containing 15%HF.Comprehensive treatments were carried out after the patient was admitted.Ventricular fibrillation occurred 9 times within the first 2 h,and the lowest serum Ca2+concentration was 0.192 mmol/L.A dose of calcium gluconate(37 g)was intravenously supplied during the first 24 h,and the total amount of calcium gluconate supplementation was 343 g.Extracorporeal membrane oxygenation(ECMO)was applied for 8 d to handle the acute respiratory distress syndrome(ARDS)induced by the HF inhalation injury.The patient was discharged after 99 d of comprehensive treatment,including skin grafting.CONCLUSION Extensive HF burns combined with an inhalation injury led to a potentially fatal electrolyte imbalance and ARDS.Adequate and timely calcium supplementation and ECMO application were the keys to successful treatment of the patient. 展开更多
关键词 Hydrofluoric acid burn INHALATION injury HYPOCALCEMIA Acute respiratory distress syndrome EXTRACORPOREAL membrane OXYGENATION Case report
下载PDF
Effect of indium addition on the microstructural formation and soldered interfaces of Sn-2.5Bi-1Zn-0.3Ag lead-free solder 被引量:3
12
作者 Ming-jie Dong Zhi-ming Gao +2 位作者 Yong-chang Liu xun wang Li-ming Yu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第11期1029-1035,共7页
The microstructural formation and properties of Sn-2.5Bi-xIn-1Zn-0.3Ag (in wt%) alloys and the evolution of soldered interfaces on a Cu substrate were investigated. Apart from the relatively low melting point (about 1... The microstructural formation and properties of Sn-2.5Bi-xIn-1Zn-0.3Ag (in wt%) alloys and the evolution of soldered interfaces on a Cu substrate were investigated. Apart from the relatively low melting point (about 195?C), which is close to that of conventional eutectic Sn-Pb solder, the investigated solder presents superior wettability, solderability, and ductility. The refined equiaxial grains enhance the mechanical properties, and the embedded bulk intermetallic compounds (IMCs) (Cu6Sn5 and Cu5Zn8) and granular Bi particles improve the joint reliability. The addition of In reduces the solubility of Zn in the β-Sn matrix and strongly influences the separation and growth behaviors of the IMCs. The soldered interface of Sn-2.5Bi-xIn-1Zn-0.3Ag/Cu consists of Cu-Zn and Cu-Sn IMC layers. 展开更多
关键词 无铅焊料 接口 焊接 显微组织 金属间化合物 机械性能 金属化合物 微观结构
下载PDF
Lnc-RAP3对小鼠3T3-L1前脂肪细胞分化的影响 被引量:4
13
作者 李欢 冯晋川 +3 位作者 李贵林 王讯 李明洲 刘海峰 《遗传》 CAS CSCD 北大核心 2018年第9期758-766,共9页
长链非编码RNA(long non-coding RNA,lnc RNA)是一类长度大于200nt、没有长开放阅读框架但往往具有m RNA结构特征的RNA,可以在转录及转录后水平参与基因的表达调控。近年来,有研究证实lnc RNA对脂肪生成具有重要作用。Lnc-RAP3位于小鼠(... 长链非编码RNA(long non-coding RNA,lnc RNA)是一类长度大于200nt、没有长开放阅读框架但往往具有m RNA结构特征的RNA,可以在转录及转录后水平参与基因的表达调控。近年来,有研究证实lnc RNA对脂肪生成具有重要作用。Lnc-RAP3位于小鼠(Mus musculus)17号染色体,其表达量在小鼠脂肪细胞分化前后呈现显著差异,但其具体的生物学功能尚不清楚。为探讨lnc-RAP3在小鼠3T3-L1前脂肪细胞成脂分化中的作用,本文首先构建了lnc-RAP3的真核表达载体pc DNA3.1-RAP3,利用脂质体将pc DNA3.1-RAP3和人工合成的lnc-RAP3的si RNAs分别转染3T3-L1前脂肪细胞,并对转染后的细胞进行诱导分化,并通过油红O染色、q RT-PCR检测成脂分化相关基因表达等方法比较过表达和敲降lnc-RAP3对3T3-L1前脂肪细胞成脂分化的影响。结果显示,过表达lnc-RAP3后,细胞内脂滴聚集显著减少(P<0.05),在诱导分化第0 d、2 d和4 d时C/EBPα、Glut4、PPARγ、LPL和FAS的表达水平均呈显著(P<0.05)或极显著(P<0.01)下降;敲降lnc-RAP3后,细胞内脂滴聚集显著增多(P<0.05),同时在诱导分化第0 d、2 d时PPARγ、LPL、C/EBPα、FAS和Glut4的表达水平呈显著(P<0.05)或极显著(P<0.01)升高。本研究结果表明,lnc-RAP3可能通过影响成脂分化相关基因的表达来抑制3T3-L1前脂肪细胞的成脂分化。 展开更多
关键词 lnc-RAP3 3T3-L1前脂肪细胞 成脂分化
下载PDF
Nonlinear primary resonance analysis for a coupled thermo-piezoelectric-mechanical model of piezoelectric rectangular thin plates 被引量:1
14
作者 xun wang Chunxia XUE Haitao LI 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2019年第8期1155-1168,共14页
A model of piezoelectric rectangular thin plates with the consideration of the coupled thermo-piezoelectric-mechanical effect is established. Based on the von Kar- man large deflection theory, the nonlinear vibration ... A model of piezoelectric rectangular thin plates with the consideration of the coupled thermo-piezoelectric-mechanical effect is established. Based on the von Kar- man large deflection theory, the nonlinear vibration governing equation is obtained by using Hamilton’s principle and the Rayleigh-Ritz method. The harmonic balance method (HBM) is used to analyze the first-order approximate response and obtain the frequency response function. The system shows non-linear phenomena such as hardening nonlinear- ity, multiple coexistence solutions, and jumps. The effects of the temperature difference, the damping coefficient, the plate thickness, the excited charge, and the mode on the pri- mary resonance response are theoretically analyzed. With the increase in the temperature difference, the corresponding frequency jumping increases, while the resonant amplitude decreases gradually. Finally, numerical verifications are carried out by the Runge-Kutta method, and the results agree very well with the theoretical results. 展开更多
关键词 PIEZOELECTRIC rectangular thin plate thermo-piezoelectric-mechanical coupling HARMONIC BALANCE method (HBM) primary resonance ANALYSIS
下载PDF
表面增强拉曼散射光谱结合化学计量学方法对蜂蜜中双甲脒的高效检测(英文) 被引量:1
15
作者 聂新明 王静 +4 位作者 王勋 田亚平 陈斯 龙洲洋 宗成华 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第4期444-450,I0002,共8页
本文建立了一种灵敏、快速、环保的表面增强拉曼光谱(SERS)方法,以银纳米棒阵列为基底,测定了蜂蜜中微量的双甲脒.银纳米棒采用斜角沉积法制备,具有良好的SERS活性,增强因子为-10^7.利用密度泛函理论首先对双甲脒的特征峰进行了归属.进... 本文建立了一种灵敏、快速、环保的表面增强拉曼光谱(SERS)方法,以银纳米棒阵列为基底,测定了蜂蜜中微量的双甲脒.银纳米棒采用斜角沉积法制备,具有良好的SERS活性,增强因子为-10^7.利用密度泛函理论首先对双甲脒的特征峰进行了归属.进一步探测了该方法用于双甲脒检测的可行性,其对蜂蜜中双甲脒的最低检测浓度为0.08mg/kg.另一方面,采用偏最小二乘回归分析方法,对SERS全波谱进行分析并与双甲脒的浓度进行关联,建立了一种多元的双甲脒预测模型.结果表明,蜂蜜样本中双甲脒的预测浓度与实际浓度吻合较好.与传统的基于SERS单峰强度的单变量定量模型相比,本文提出的多元预测模型综合了双甲脒的所有特征峰,提高了检测精度和抗干扰能力. 展开更多
关键词 双甲脒 表面增强拉曼光谱方法 斜角沉积 蜂蜜检测 传感 银纳米棒 密度泛函理论 偏最小二乘回归法
下载PDF
Bubble translation driven by pulsation in a double-bubble system 被引量:1
16
作者 张玲玲 陈伟中 +3 位作者 张圆媛 武耀蓉 王寻 赵帼英 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第3期265-269,共5页
The pulsation and translation of two cavitation bubbles are studied numerically in sound field. The results show that bubbles' pulsation driven by the sound makes them translate. Different pulsations lead to diffe... The pulsation and translation of two cavitation bubbles are studied numerically in sound field. The results show that bubbles' pulsation driven by the sound makes them translate. Different pulsations lead to different translations. Two bubbles will be mutually attractive to each other if they pulsate in phase, while they will be repulsive if out of phase. Furthermore,the secondary Bjerknes force for small phase difference is attractive, and it becomes repulsive for other phase differences up to π phase difference due to the nonlinear effect, although the attractive strength between two bubbles is much larger than the repulsive strength. Finally, one bubble pulsation and the other bubble stationary make the bubbles repel each other. 展开更多
关键词 DOUBLE BUBBLE dynamics PULSATION TRANSLATION phase DIFFERENCE
原文传递
Influence of cascade reservoirs on spatiotemporal variations of hydrogeochemistry in Jinsha River 被引量:1
17
作者 Qiu-sheng Yuan Pei-fang wang +3 位作者 Juan Chen Chao wang Sheng Liu xun wang 《Water Science and Engineering》 EI CAS CSCD 2021年第2期97-108,共12页
River hydrogeochemistry offers necessary guidance for effective water environmental management.However,the influence of cascade reservoirs on river hydrogeochemistry remains unknown.In this study,the Jinsha River,the ... River hydrogeochemistry offers necessary guidance for effective water environmental management.However,the influence of cascade reservoirs on river hydrogeochemistry remains unknown.In this study,the Jinsha River,the headwaters of the Yangtze River of China,was selected to investigate the spatiotemporal variations of hydrogeochemistry after the construction of six cascade reservoirs.Major ions,total dissolved solids,electrical conductivity,and pH values of sampled water in the upper natural reaches and lower reservoir-regulated reaches were analyzed in both flood and dry seasons.The results of Piper diagram and Gibbs plots showed that the hydrogeochemistry of the Jinsha River was naturally controlled by both evaporation-crystallization and carbonate weathering processes,but it was also artificially affected by reservoirs.The impoundment of cascade reservoirs affected the hydrodynamic condition of the river.The river flow in the flood season was reduced by approximately 24.5%,altering the proportions of water sources and leading to notable hydrogeochemical alterations in reservoir-regulated reaches.Conversely,river hydrogeochemistry generally remained unchanged in the dry season,owing to the insignificant effect of cascade reservoirs on river flow.In contrast to what has been observed in previous studies of individual reservoirs,the cumulative influence of cascade reservoirs on the Jinsha River flow regime did not cause abrupt hydrogeochemical changes between the upstream and downstream areas of each reservoir.Moreover,the water quality assessments revealed that the impoundment of cascade reservoirs improved downstream irrigational water quality,with lower Naþratio values in the flood season.This study provides the earliest evaluation of cascade reservoir influence on the hydrogeochemistry of the Jinsha River.The findings of this study can be used as a reference for scientific guidelines for future environmental management of cascade reservoirs in large rivers. 展开更多
关键词 River hydrogeochemistry Spatiotemporal variations Controlling factors Cascade reservoirs Jinsha River
下载PDF
Isolation and bioinformatics analysis of differentially methylated genomic fragments in human gastric cancer 被引量:1
18
作者 Ai-Jun Liao Qi Su +2 位作者 xun wang Bin Zeng Wei Shi 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第9期1333-1338,共6页
AIM:To isolate and analyze the DNA sequences which are methylated differentially between gastric cancer and normal gastric mucosa. METHODS: The differentially methylated DNA sequences between gastric cancer and normal... AIM:To isolate and analyze the DNA sequences which are methylated differentially between gastric cancer and normal gastric mucosa. METHODS: The differentially methylated DNA sequences between gastric cancer and normal gastric mucosa were isolated by methylation-sensitive representational difference analysis (MS-RDA). Similarities between the separated fragments and the human genomic DNA were analyzed with Basic Local Alignment Search Tool (BLAST). RESULTS: Three differentially methylated DNA sequences were obtained, two of which have been accepted by GenBank. The accession numbers are AY887106 and AY887107. AY887107 was highly similar to the 11th exon of LOC440683 (98%), 3' end of LOC440887 (99%), and promoter and exon regions of DRD5 (94%). AY887106 was consistent (98%) with a CpG island in ribosomal RNA isolated from colorectal cancer by Minoru Toyota in 1999. CONCLUSION: The methylation degree is different between gastric cancer and normal gastric mucosa. The differentially methylated DNA sequences can be isolated effectively by MS-RDA. 展开更多
关键词 胃癌 DNA甲基化 生物信息学 胃黏膜
下载PDF
The isotopic evidence of gas source of the cold mineral springs with high pCO_2 in Wudalianchi 被引量:1
19
作者 Xumei MAO Yanxin wang xun wang 《Chinese Journal Of Geochemistry》 EI CAS 2006年第B08期146-146,共1页
关键词 矿物 天然气 热量 矿化作用
下载PDF
Genome-wide identification and expression analyses of homeodomain-leucine zipper family genes reveal their involvement in stress response in apple(Malus×domestica) 被引量:1
20
作者 Quanyan Zhang Tao Chen +5 位作者 xun wang Jiahui wang Kaidi Gu Jianqiang Yu Dagang Hu Yujin Hao 《Horticultural Plant Journal》 SCIE CSCD 2022年第3期261-278,共18页
The homeodomain-leucine zipper(HD-Zip)family has been shown to perform amultitude of functions during plant development and stress responses;however,the familymembers and functions have not been identified in apple(Ma... The homeodomain-leucine zipper(HD-Zip)family has been shown to perform amultitude of functions during plant development and stress responses;however,the familymembers and functions have not been identified in apple(Malus×domestica).In this study,83 HD-Zips(MdHDZs)were identified in the apple genome.They were assembled into four subgroups according to the classification in Arabidopsis,where MdHDZs in the same subgroup had similar gene structures and conserved protein motifs.Putative cis-element analysis of MdHDZs promoter regions uncovered numerous elements related to the response of stress and plant hormones.In addition,twelve transcripts of the MdHDZs showed different expression patterns under salt,drought,low temperature and ABA stresses by quantitative reverse transcription-PCR(qRT-PCR)assay.To further explore the function of MdHDZs in apple,MdHDZ3 was selected to verify its function under salt,low temperature and ABA stresses;and genetic transformation was used to obtain MdHDZ3 transgenic apple calli.The results demonstrated that MdHDZ3 increased sensitivity to salt,low temperature and abscisic acid in apple calli,suggesting that MdHDZ3 plays an important role in response to stresses.Subcellular localization and three-dimensional structural analysis revealed that MdHDZ3 was a nuclear-localized protein.Taken together,these findings provide potential information for further identification of HD-Zip proteins in apple. 展开更多
关键词 APPLE HD-ZIP HDZ Gene expression Stress response
下载PDF
上一页 1 2 5 下一页 到第
使用帮助 返回顶部