期刊文献+
共找到18,380篇文章
< 1 2 250 >
每页显示 20 50 100
高效低时延分级多PAN太赫兹无线网络MAC层优化协议
1
作者 刘洋 任智 +1 位作者 古金东 周逊 《小型微型计算机系统》 CSCD 北大核心 2024年第8期1966-1971,共6页
针对现有分级多PAN太赫兹无线网络MAC(Medium Access Control)协议中存在的子网形成方案不合理以及私有CTA(Channel Time Allocation)与子网内实际负载不匹配等问题,提出了一种高效低时延的MAC层优化协议.该协议采用基于泛听的按需形成... 针对现有分级多PAN太赫兹无线网络MAC(Medium Access Control)协议中存在的子网形成方案不合理以及私有CTA(Channel Time Allocation)与子网内实际负载不匹配等问题,提出了一种高效低时延的MAC层优化协议.该协议采用基于泛听的按需形成子网机制避免了子网分布不均匀以及因子网形成后没有节点加入而造成的私有CTA资源浪费的问题.在子网形成后,子微微网协调器(Piconet Coordinator,PNC)根据子网内实际负载情况自适应选择私有CTA时隙资源优化机制,让有数据传输需求的节点及时将数据发出.仿真结果表明,所提出的方案能有效地降低数据帧平均接入时延,提高吞吐量以及数据帧的传输成功率. 展开更多
关键词 太赫兹 分级 pan 无线网络 媒体访问控制协议 低时延
下载PDF
ZnO@PAN柔性复合纳米纤维膜的制备及压电特性
2
作者 张瑞 李银辉 +2 位作者 高飞 梁建国 李朋伟 《微纳电子技术》 CAS 2024年第6期45-53,共9页
采用静电纺丝技术,通过两步低温水热法制备了ZnO@聚丙烯腈(PAN)柔性复合纳米纤维膜。研究了静电纺丝电压和滚筒转速对ZnO@PAN柔性复合纳米纤维膜压电和铁电性能的影响。研究结果表明,当静电纺丝电压为20 kV、滚筒速度为1000 r/min时,ZnO... 采用静电纺丝技术,通过两步低温水热法制备了ZnO@聚丙烯腈(PAN)柔性复合纳米纤维膜。研究了静电纺丝电压和滚筒转速对ZnO@PAN柔性复合纳米纤维膜压电和铁电性能的影响。研究结果表明,当静电纺丝电压为20 kV、滚筒速度为1000 r/min时,ZnO@PAN柔性复合纳米纤维膜的输出性能达到最佳,输出开路电压可达到5.5 V,短路电流可达到0.61μA,剩余极化强度可达到0.43μC/cm^(2)。在外部负载电阻为13 MΩ时,柔性复合纳米纤维膜达到最大输出功率0.63μW。经过5000次循环敲击测试,所制备的ZnO@PAN柔性复合纳米纤维膜输出性能保持稳定。通过ZnO@PAN柔性复合纳米纤维膜可实时监测握力器微握、半握、全握三种不同的状态,在自供电柔性压力传感器领域有着广阔的应用前景。 展开更多
关键词 ZnO@聚丙烯腈(pan) 柔性复合纳米纤维膜 静电纺丝技术 压力传感器 柔性材料
下载PDF
CBCT与PAN预测下颌近中低位阻生第三磨牙拔除术损伤水平的临床比较
3
作者 刘喆 武辉 黎昌学 《牙体牙髓牙周病学杂志》 2024年第3期142-146,共5页
目的:运用锥形束CT(CBCT)及口腔曲面断层片(PAN)引导拔除下颌近中低位第三磨牙,探讨CBCT作为术前预测手段是否存在优越性。方法:选取于2022年1月至2023年8月在石河子大学第一附属医院就诊的213例患者,分为PAN组和CBCT组,对两组患者分别... 目的:运用锥形束CT(CBCT)及口腔曲面断层片(PAN)引导拔除下颌近中低位第三磨牙,探讨CBCT作为术前预测手段是否存在优越性。方法:选取于2022年1月至2023年8月在石河子大学第一附属医院就诊的213例患者,分为PAN组和CBCT组,对两组患者分别进行拔牙手术,采集患者术前及术后龈沟液并采用酶联免疫吸附实验(ELISA)测定炎症及疼痛因子浓度;运用统计学方法对比两组在各类指标的差异性。结果:CBCT作为术前评估手段相较传统PAN在明确牙根与MC接触关系上具有优越性(P <0.05),且CBCT组手术时间短、手术并发症发生率低(P <0.05);通过ELISA测定结果得出CBCT组患者龈沟液中炎症因子及疼痛因子的术前术后浓度变化值相较PAN组浓度变化值低(P <0.05)。结论:CBCT相比PAN在评估牙根与下颌管(MC)接触关系这类风险因素方面具有优越性,且应用CBCT作为术前评估手段进行拔牙手术其手术时间短,并发症少,术后损伤小。 展开更多
关键词 pan CBCT 下颌近中低位第三磨牙
下载PDF
基于BTO/PAN复合纳米纤维膜的柔性压电纳米发电机
4
作者 马俊格 李银辉 +2 位作者 耿爱森 梁建国 李朋伟 《微纳电子技术》 CAS 2024年第9期74-82,共9页
采用简单的一步水热法合成了钛酸钡纳米颗粒(BTO NP),通过静电纺丝法制备了BTO/聚丙烯腈(PAN)复合纳米纤维膜,并基于该膜制备了柔性复合压电纳米发电机。研究结果表明,随着BTO掺杂质量分数的增加,BTO/PAN柔性复合压电纳米发电机的输出... 采用简单的一步水热法合成了钛酸钡纳米颗粒(BTO NP),通过静电纺丝法制备了BTO/聚丙烯腈(PAN)复合纳米纤维膜,并基于该膜制备了柔性复合压电纳米发电机。研究结果表明,随着BTO掺杂质量分数的增加,BTO/PAN柔性复合压电纳米发电机的输出电压先增大后减小。当BTO的质量分数为15%时,BTO/PAN柔性复合压电纳米发电机的输出性能最佳,输出电压可达10.2 V,输出电流可达1.52μA。当负载电阻为12 MΩ时,其最大输出功率约为3.72μW,与纯PAN纳米纤维膜压电纳米发电机相比,输出性能有明显改善。经过5000次循环测试结果表明,BTO/PAN柔性复合压电纳米电机的的输出性能没有明显变化,因此其具有较好的稳定性。同时,该压电纳米发电机能够检测人体的不同状态,为研发高性能和自供电的可穿戴生物电子产品提供了参考。 展开更多
关键词 压电纳米发电机 纳米纤维 静电纺丝 纳米颗粒(NP) 聚丙烯腈(pan) 钛酸钡(BTO)
下载PDF
参芪蛭龙汤含药血清对PAN损伤MPC5细胞凋亡的抑制作用
5
作者 薛丕良 王文文 +2 位作者 李星宇 刘星 王顺 《辽宁中医杂志》 CAS 北大核心 2024年第4期196-199,I0004,共5页
目的探讨参芪蛭龙汤含药血清对puromycin aminonucleoside(PAN)损伤MPC5细胞凋亡的抑制作用。方法制备参芪蛭龙汤大鼠含药血清。MPC5细胞随机分为空白组、模型组、给药组,空白组和模型组用10%大鼠空白血清干预,给药组用10%参芪蛭龙汤含... 目的探讨参芪蛭龙汤含药血清对puromycin aminonucleoside(PAN)损伤MPC5细胞凋亡的抑制作用。方法制备参芪蛭龙汤大鼠含药血清。MPC5细胞随机分为空白组、模型组、给药组,空白组和模型组用10%大鼠空白血清干预,给药组用10%参芪蛭龙汤含药血清干预,培养24 h后,模型组和给药组加入50 mg/L的PAN干预24 h后,倒置显微镜下观察MPC5细胞的形态结构,MTS法检测细胞增殖,Hoechst33342/PI染色法检测细胞凋亡,AnnexinV-FITC/PI双染法检测细胞凋亡,Western-blot法检测MPC5细胞中BAX、Bcl-2、Caspase-3、Nephrin、Podocin蛋白的表达。结果与模型组比较,足突结构较明显,数量较多;能够促进PAN处理后MPC5细胞的增殖(P<0.05);降低细胞凋亡率(P<0.05,P<0.01);降低细胞中Bax蛋白的表达(P<0.01)、降低cleaved-Caspase-3/Caspase-3蛋白比值(P<0.05),升高Bcl-2、Nephrin蛋白的表达(P<0.05,P<0.01)。结论参芪蛭龙汤能够修复裂孔隔膜蛋白、减少足细胞凋亡,对维持肾小球的正常滤过功能具有改善作用,从而减少蛋白尿。 展开更多
关键词 膜性肾病 足细胞 pan 细胞凋亡 裂孔隔膜
下载PDF
KH-560处理时间对PAN基碳纤维沥青复合材料性能的影响
6
作者 曹国斌 张燕 《功能材料》 CAS CSCD 北大核心 2024年第4期4223-4229,共7页
以硅烷偶联剂KH-560改性的PAN基碳纤维为添加材料,制备了不同KH-560处理时间的PAN基碳纤维沥青复合材料。通过车辙试验、冻融劈裂试验和间接拉伸疲劳试验等研究了KH-560处理时间对沥青复合材料高温稳定性、低温抗裂性、水稳定性、疲劳... 以硅烷偶联剂KH-560改性的PAN基碳纤维为添加材料,制备了不同KH-560处理时间的PAN基碳纤维沥青复合材料。通过车辙试验、冻融劈裂试验和间接拉伸疲劳试验等研究了KH-560处理时间对沥青复合材料高温稳定性、低温抗裂性、水稳定性、疲劳性能和吸声性能的影响。结果表明,经过KH-560处理后的PAN基碳纤维表面的粗糙度增加,当KH-560处理时间为2 h时,纤维凹槽较深,与沥青的作用面积增大,纤维在复合材料中形成了致密网状结构,增强了PAN基碳纤维复合材料的稳定性。当KH-560处理时间为2 h时,PAN基碳纤维沥青复合材料的高温性能、低温抗裂性能、水稳定性和疲劳性能均最佳,此时其45和60 min的变形量、破坏劲度模量达到最小值,分别为1.851和2.117 mm、2 201 MPa;动稳定度、劈裂抗拉强度和破坏拉伸应变达到最大值,分别为3 077次/mm、4.6 MPa和3479με。在250~1 000 Hz和1 000~1 600 Hz范围内,当KH-560处理时间为2 h时,沥青复合材料的平均吸声系数均达到最大值,分别为0.116和0.127,较未处理的沥青复合材料分别提高了39.76%和45.98%,吸声降噪性能提升显著。综上可知,KH-560的最佳处理时间为2 h。 展开更多
关键词 KH-560处理 pan基碳纤维 沥青 复合材料 疲劳性能 吸声性能
下载PDF
苏皖鲁豫典型城市过氧乙酰硝酸酯(PAN)污染特征分析 被引量:1
7
作者 秦志勇 张红 +4 位作者 汪水兵 洪星园 王馨琦 朱森 卫尤文 《环境化学》 CAS CSCD 北大核心 2024年第5期1599-1607,共9页
为探究苏皖鲁豫区域光化学污染特征,于2021年10月和2022年6月在淮北市开展光化学污染产物过氧乙酰硝酸酯(peroxyacetyl nitrate,PAN)的在线监测,分析了PAN浓度特征、空间来源、产生速率和变化趋势.观测结果表明,观测处2021年10月PAN的... 为探究苏皖鲁豫区域光化学污染特征,于2021年10月和2022年6月在淮北市开展光化学污染产物过氧乙酰硝酸酯(peroxyacetyl nitrate,PAN)的在线监测,分析了PAN浓度特征、空间来源、产生速率和变化趋势.观测结果表明,观测处2021年10月PAN的浓度范围为(0.08—1.44)×10^(−9),2022年6月的浓度范围为(0.61—5.72)×10^(−9);PAN的峰值大部分出现在NO/NO_(2)比值较低的时段.结合气团后向轨迹,2021年10月观测处PAN的潜在源贡献函数(PSCF)高值区范围出现在南部方向,可能是因为西南方向相近城市较高的前体物排放;2022年6月高值区主要出现在北部和东南部,显示山东省西南部是潜在源贡献地区,东南方向的气团在工业化程度较高的城市群之间存在长距离运输. 展开更多
关键词 过氧乙酰硝酸酯 (pan) 光化学污染特征 苏皖鲁豫 在线监测
下载PDF
五味子乙素对胰腺癌Pan02细胞增殖的抑制作用及其机制 被引量:1
8
作者 傅家财 秦玲莎 +5 位作者 杨露 宋美慧 张仙映 刘晓翠 李凤金 齐玲 《吉林大学学报(医学版)》 CAS CSCD 北大核心 2024年第3期638-646,共9页
目的:探讨五味子乙素对胰腺癌Pan02细胞增殖的抑制作用,并阐明其作用机制。方法:采用CCK-8法检测不同浓度(0、0.78、1.56、3.12、6.25、12.50和25.00 mg·L^(-1))五味子乙素作用下Pan02细胞增殖率,以选择五味子乙素作用的最适浓度... 目的:探讨五味子乙素对胰腺癌Pan02细胞增殖的抑制作用,并阐明其作用机制。方法:采用CCK-8法检测不同浓度(0、0.78、1.56、3.12、6.25、12.50和25.00 mg·L^(-1))五味子乙素作用下Pan02细胞增殖率,以选择五味子乙素作用的最适浓度和最佳作用时间。小鼠胰腺癌Pan02细胞分为对照组(0 mg·L^(-1)五味子乙素)、2.5 mg·L^(-1)五味子乙素组、5.0 mg·L^(-1)五味子乙素组和10.0 mg·L^(-1)五味子乙素组。光学显微镜观察各组Pan02细胞形态表现,5-乙基-2'-脱氧尿嘧啶核苷(EdU)染色法检测各组Pan02细胞中EdU阳性细胞率,流式细胞术检测各组不同细胞周期Pan02细胞百分率和细胞凋亡率,Western blotting法检测各组Pan02细胞周期和凋亡相关蛋白表达水平。结果:CCK-8法,五味子乙素作用Pan02细胞48和72 h后,与0 mg·L^(-1)五味子乙素比较,其他浓度五味子乙素作用下Pan02细胞增殖率明显降低(P<0.01),72 h时细胞抑制作用最明显。选择0、2.5、5.0和10.0 mg·L^(-1)五味子乙素作用Pan02细胞,作用时间为72 h。对照组Pan02细胞呈长梭形,状态良好,紧密且贴壁生长,细胞器和细胞质正常;2.5和5.0 mg·L^(-1)五味子乙素组Pan02细胞体积减小,细胞之间黏连消失,细胞膜虽完整但通透性增强,细胞质皱缩,细胞内部产生空泡结构,部分呈碎片状漂浮于溶液表面;10.0 mg·L^(-1)五味子乙素组Pan02细胞有明显凋亡小体生成,呈现凋亡状态。EdU染色法,与对照组比较,2.5、5.0和10.0 mg·L^(-1)五味子乙素组Pan02细胞中EdU阳性细胞率均明显降低(P<0.01)。流式细胞术,与对照组比较,2.5、5.0和10.0 mg·L^(-1)五味子乙素组Pan02细胞S期细胞百分率明显升高(P<0.01),G_(2)/M期细胞百分率明显降低(P<0.01),5.0和10.0 mg·L^(-1)五味子乙素组G_(0)/G_(1)期细胞百分率明显降低(P<0.01);与对照组比较,2.5、5.0和10.0 mg·L^(-1)五味子乙素组Pan02细胞凋亡率明显升高(P<0.01)。Western blotting法,与对照组比较,2.5 mg·L^(-1)五味子乙素组Pan02细胞中p27、B细胞淋巴瘤2(Bcl-2)相关X蛋白(Bax)、裂解的半胱氨酸天冬氨酸蛋白酶3(cleaved Caspase-3)和裂解的多聚二磷酸腺苷(ADP)核糖聚合酶(cleaved PARP)蛋白表达水平明显升高(P<0.05或P<0.01);5.0和10.0 mg·L^(-1)五味子乙素组Pan02细胞中细胞周期蛋白(Cyclin)A2、Cyclin E2和Bcl-2蛋白表达水平均明显降低(P<0.05或P<0.01),p27、 Bax、 cleaved Caspase-3和cleaved PARP蛋白表达水平均明显升高(P<0.01)。结论:五味子乙素具有抑制胰腺癌Pan02细胞增殖的作用,其作用机制可能与激活半胱氨酸天冬氨酸蛋白酶3(Caspase-3)通路诱导细胞凋亡和激活p27蛋白并诱导细胞周期S期阻滞有关。 展开更多
关键词 五味子乙素 胰腺肿瘤 pan02细胞 细胞凋亡 细胞周期
下载PDF
PAN/rGO纤维膜应变传感器的制备及性能
9
作者 郑浩栋 张华鹏 《纺织科学与工程学报》 CAS 2024年第3期85-90,共6页
石墨烯材料被广泛用于应变传感器的制备中,但是如何使其具备更高的灵敏度一直是研究人员的一个困扰。基于石墨烯优异的导电性和拉伸性,结合质量轻且多孔的聚丙烯腈(PAN)纳米纤维膜制备一种高灵敏度柔性应变传感器。通过设置定量的PAN与... 石墨烯材料被广泛用于应变传感器的制备中,但是如何使其具备更高的灵敏度一直是研究人员的一个困扰。基于石墨烯优异的导电性和拉伸性,结合质量轻且多孔的聚丙烯腈(PAN)纳米纤维膜制备一种高灵敏度柔性应变传感器。通过设置定量的PAN与三个梯度质量的石墨烯形成对照实验,探究石墨烯含量对复合材料的性能影响。结果表明,石墨烯质量分数增加,会促使PAN/rGO复合材料的孔隙结构变大且均匀,石墨烯含量越高,复合材料电阻变化率越大,电导率越大,在吹气实验中,2 s内就可以完成一次气体压力检测,是制备高灵敏度形变传感器的理想材料。 展开更多
关键词 石墨烯 还原氧化石墨烯 聚丙烯腈 气体传感器
下载PDF
NiFe-LDH@Cu_(2)O/PAN光催化纤维的制备及性能研究
10
作者 高云莉 王琛 +1 位作者 党袁鹏 司佳佳 《纺织器材》 2024年第1期12-16,共5页
针对Cu_(2)O光催化活性较低,粉末光催化剂不易回收及重复使用性差等问题,采用静电纺丝方法制备NFC/PAN光催化纤维;通过引入可在其夹层中容纳阴离子的层状双氢氧化物,用NiFe-LDH对Cu_(2)O进行改性,并将其负载于PAN纤维,使用扫描电子显微... 针对Cu_(2)O光催化活性较低,粉末光催化剂不易回收及重复使用性差等问题,采用静电纺丝方法制备NFC/PAN光催化纤维;通过引入可在其夹层中容纳阴离子的层状双氢氧化物,用NiFe-LDH对Cu_(2)O进行改性,并将其负载于PAN纤维,使用扫描电子显微镜、能谱仪、万能试验机、紫外可见吸收光谱等测试方法,评价不同Ni_(3)Fe_(1)-LDH@Cu_(2)O添加量对光催化纤维的性能影响。指出:在可见光照射60 min后,NFC质量百分比为5%的Ni_(3)Fe_(1)-LDH@Cu_(2)O/PAN对亚甲基蓝的降解效果最佳,达到91.7%,且其比表面积为76.3 cm^(2)/g,具有一定力学稳定性,重复使用5次后其降解率依旧达85%以上;5%Ni_(3)Fe_(1)-LDH@Cu_(2)O/PAN光催化效果在短时间可达到高效率,其光催化纤维降解速率常数最大,为0.0226,拉伸断裂强力提高3.35倍。 展开更多
关键词 NiFe-LDH@Cu_(2)O/pan光催化纤维 层状双氢氧化物 聚丙烯腈纤维 NFC 亚甲基蓝 降解
下载PDF
Characteristics of Gold Mineralization at the Baguiomo Gold Panning Site, Koudougou Region, Burkina Faso, West Africa
11
作者 Pascal Ouiya Aziz Fayçal Tarnagda Martial Eric Fozing 《Open Journal of Geology》 CAS 2024年第1期1-18,共18页
The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are ... The Birimian Baguiomo formations are located in the northern part of the Boromo greenstone belt. In this belt, the volcanic rocks (tholeiitic basalt, calcalkaline basalt, andesite) hosting the gold mineralization are located in the Kwademen-Baguiomo shear zone. This mineralization, located only a few kilometers from the Kwademen gold deposit, is uncharacterized and, together with the latter, could constitute a gold potential capable of being economically exploitable. It is in this sense that this work is carried out with a view to characterizing the gold mineralization of the Baguiomo gold panning site. To carry out this work, we have made direct field measurements, combined with microstructures, and combined all this with data from geochemical rock analysis of the basalts that are the main host formations. Geochemical data show that tholeitic basalts formed from a mantle plume that was emplaced in an oceanic plateau context. Calc-alkaline basalts and andesites are comparable to Paleoproterozoic tholeitic basalts (PTH3), which are slightly enriched in light rare earths. Fertility tests show that these basalts concentrate between 3 and 6 ppb of gold at the time of accretion, which is sufficient for remobilization of this primary gold during the Eburnian orogeny to yield a deposit of around 4 - 5 Moz. Gold mineralization is associated with pyrite crystals when the latter are disseminated in the rock mass, whereas it is associated with hematite in quartz veins concordant with S1 shear deformation. It is mainly the pyrite crystals in the pressure shadows that contain the gold grains, whose development would be synchronous with micro-shear zone reactivation during the first phase of D1<sub>B</sub> deformation. The second phase of D2<sub>B</sub> deformation, which is a crenulation or fracture schistosity, does not significantly affect the shear deformation that controls mineralization. 展开更多
关键词 Kwademen-Baguiomo Shear Zone Gold panning Site Gold Mineralization Eburnian Orogeny
下载PDF
New findings of Changxingaspis(Xiushuiaspidae,Galeaspida)from the Silurian of Tarim Basin and Zhejiang Province,China
12
作者 LI Xutong ZHANG Yumeng +5 位作者 LIN Xianghong ZHU Min ZHAO Wenjin TANG Lizhou SHAN Xianren GAI Zhikun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2024年第3期531-540,共10页
New discovery of the early Silurian fossil fish Changxingaspis(Xiushuiaspidae,Galeaspida),Changxingaspis nianzhongi sp.nov.and C.gui,are described from the Tataertag Formation in Tarim Basin and the Kangshan Formation... New discovery of the early Silurian fossil fish Changxingaspis(Xiushuiaspidae,Galeaspida),Changxingaspis nianzhongi sp.nov.and C.gui,are described from the Tataertag Formation in Tarim Basin and the Kangshan Formation in Zhejiang Province,respectively.C.nianzhongi mainly differs from C.gui in the shape of the median dorsal opening that is transverse elliptic with a width/length ratio of about 3.0,the long lateral transverse canals extending to the lateral margin of the headshield,and the second lateral transverse canal with dichotomous branchings.Discovery of C.nianzhongi from the Tataertag Formation and C.gui from the Kangshan Formation provide direct evidence on the specific level for the correlation between these two formations,which further supports the Silurian fish-bearing red beds in northwest Zhejiang belonging to the Silurian Lower Red Beds(LRBs)rather than the Upper Red Beds(URBs).Additionally,as the first record of the Changxingaspis in Tarim Basin,it extends the paleogeographical distribution of this genus from the South China Block to the Tarim Block,providing new evidence to support faunal exchanges between these two blocks and the hypothesis of a united Tarim-South China Block during the early Silurian. 展开更多
关键词 vertebrate paleontology Galeaspids Changxingaspis new taxon Tataertag Formation Kangshan Formation Aeronian-Telychian TARIM zhejiang
下载PDF
Exploring the Spatiotemporal Changes and Driving Forces of Ecosystem Services of Zhejiang Coasts,China,Under Sustainable Development Goals
13
作者 ZHANG Shu SUN Chao +2 位作者 ZHANG Yixin HU Ming SHEN Xingru 《Chinese Geographical Science》 SCIE CSCD 2024年第4期647-661,共15页
Ecosystem services(ESs)refer to the continuous provisioning of ecosystem goods and services that benefit human beings.Over recent decades,rapid urbanization has exerted significant pressure on coastal ecosystems,resul... Ecosystem services(ESs)refer to the continuous provisioning of ecosystem goods and services that benefit human beings.Over recent decades,rapid urbanization has exerted significant pressure on coastal ecosystems,resulting in biodiversity and habitat loss,environmental pollution,and the depletion of natural resources.In response to these environmental challenges,the Sustainable Development Goals(SDGs)were proposed.Given the pressing need to address these issues,understanding the changes in ESs under the SDGs is crucial for formulating specific ecological strategies.In this study,we first analyzed land use and cover change in the Zhejiang coasts of China during 2000–2020.Then,we investigated the spatiotemporal configuration of ESs by integrating carbon storage(CS),soil retention(SR),habitat quality(HQ)and water yield(WY)using the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model.The driving mechanisms of ESs,which varied by space and time,were also explored using the Geo-detector method.The results revealed that,over the past two decades:1)the Zhejiang coasts have experienced a significant increase of 2783.72 km^(2) in built-up land areas and a continuous decrease in farmland areas due to rapid urbanization;2)owing to higher precipitation,extensive vegetation cover,and reduced anthropogenic disturbances,forests emerge as a crucial land use type for maintaining ecosystem services such as HQ,CS,WY,and SR;3)ESs have generally declined across the entire Zhejiang coasts,with a significant decrease observed in the northern areas and an increase in the southern areas spatially;4)the expansion of built-up land areas emerged as the primary factor affecting ecosystem services,while the vegetation factor has been increasingly significant and is expected to become predominant in the near future.Our study provides insights of understanding of ecosystem service theory and emphasizing the importance of preserving biodiversity for long-term sustainable development,and valuable scientific references to support the ecological management decision-making for local governments. 展开更多
关键词 ecosystem services(ESs) Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model Geo-detector land use and cover change(LUCC) zhejiang coasts China
下载PDF
The Spatial-Temporal Characteristics of Meteorological Disasters in the Southwest Region of Zhejiang Province during 1953-2022
14
作者 Qi Zhang Yifan Wang +3 位作者 Zhidan Zhu Hongxia Shi Wenhao Yang Shujie Yuan 《Journal of Geoscience and Environment Protection》 2024年第3期16-27,共12页
Meteorological disasters are some of the most serious and costly natural disasters, which have larger effects on economic and social activity. Liuchun Lake is an ecotourism area in the southwest region of Zhejiang pro... Meteorological disasters are some of the most serious and costly natural disasters, which have larger effects on economic and social activity. Liuchun Lake is an ecotourism area in the southwest region of Zhejiang province, where also has experienced meteorological disasters including rainstorm and cold wave. Understanding the temporal-spatial characteristics of meteorological disasters is important for the local tourism and economic development. Based on the daily temperature and precipitation from 18 meteorological stations in the southwest of Zhejiang province during 1953-2022 and some statistical approaches, the temporal and spatial characteristics of meteorological disasters (Freezing, Rainstorm, Cold wave) are analyzed. The results indicate that 1) Rainstorm occurred frequently around the Liuchun lake, the frequency was about 8 times/a, it can also reach about 3 times/a in the other region. Freezing and cold wave (including strong cold wave and extremely cold wave) had the same spatial distribution as rainstorm, however, except for Liuchun lake, they occurred less than one time in the other regions;2) The trend of rainstorm had larger spatial difference, it increased in all the study area, but it increased more significantly around the study area than around Liuchun lake. Freezing was on the downtrend in the whole region, with 93.3% of the stations passed the 95% significant level. Cold wave also showed a declined trend, but it was insignificantly at most of the stations, only 33% of the stations passed the 90% significant level. Compared with cold wave, strong cold wave and extremely strong cold wave had weaker decline in all the regions. In general, from 1953 to 2022 rainstorm showed an increasing trend, it was the main meteorological disaster in the study area, cold wave displayed a decreasing trend, but it still occurred about 2 - 3 times/a in most regions. 展开更多
关键词 Southwest of zhejiang Province RAINSTORM Cold Wave Spatial Distribution Trend Analysis
下载PDF
Analysis of the Impact of Technical Trade Barriers on the Export of Toys-Based on Analysis of Zhejiang,China
15
作者 LIU Ningning CHEN Xiaoxi 《Chinese Business Review》 2024年第1期37-46,共10页
Technical barriers to trade,as a non-tariff barrier,have an increasing impact on the international market.As a major province in toy exports,Zhejiang Province’s toy export trade is therefore greatly hindered.This art... Technical barriers to trade,as a non-tariff barrier,have an increasing impact on the international market.As a major province in toy exports,Zhejiang Province’s toy export trade is therefore greatly hindered.This article aims to explore the impact of technical trade barriers on toy exports in Zhejiang Province and analyze countermeasures.Through literature review and some empirical analysis,it is found that technical trade barriers have greatly promoted the development of Zhejiang’s toy industry;however,they have also subjected it to impacts and pressures such as cost and technology.In response to the impact of technical trade barriers on toy exports,this article proposes corresponding countermeasures to avoid such barriers:firstly,establish a quality management system that complies with export product regulations to ensure that the products produced can meet international requirements and standards;secondly,reduce dependence on overseas markets;then enhance one’s own technology,and strengthen product innovation,in order to enhance the international competitiveness of the product and oneself;in addition,we should also explore diversified markets and expand the sales channels and coverage of our products. 展开更多
关键词 technical trade barriers zhejiang Province export of toys countermeasure analysis
下载PDF
Other Cities’Distribution Institutions for Publishing Books in Modern Chinese Libraries:Taking Huating Bookstore,the Shanghai General Distribution Office of Modern Zhejiang Library,as an Example
16
作者 HE Dan WANG Xirong 《Cultural and Religious Studies》 2024年第3期123-132,共10页
Many modern Chinese libraries have established distribution agencies in other cities to distribute books published or sold on consignment.Huating Bookstore,which was once the Shanghai General Distribution Office of Zh... Many modern Chinese libraries have established distribution agencies in other cities to distribute books published or sold on consignment.Huating Bookstore,which was once the Shanghai General Distribution Office of Zhejiang Library in modern times,is one of them.On the basis of a brief description of modern Zhejiang Library and its book publishing,as well as the overview of Huating Bookstore,the paper introduces and analyzes the ZPL Publishing Book Catalogue sent by Huating Bookstore,and the ZPL publishing and selling consignment books issued by Huating Bookstore.It points out that Huating Bookstore is a bridge between the ZPL located in Hangzhou and various retail ZPL publishing bookstores in Shanghai.Their production and sales relationship is a mutually beneficial one. 展开更多
关键词 modern Chinese libraries zhejiang Library Huating Bookstore Yu Heqin book publishing and distribution
下载PDF
一种PAN基碳纤维助剂投放装置及其投放方法
17
《高科技纤维与应用》 CAS 2024年第1期90-90,共1页
本发明提出一种PAN基碳纤维助剂投放装置及其投放方法,涉及复合材料技术领域,其中PAN基碳纤维助剂投放装置通过设置存储助剂的储料本体,内部设有定位组件的计量本体,计量本体和储料本体之间设有溢流管,溢流管置于计量本体的管口为溢流管口.
关键词 pan基碳纤维 溢流管 复合材料技术 投放装置 助剂 投放方法 本体
下载PDF
自支撑PAN/Cd_(0.8) Zn_(0.2) S/MgIn_(2)S_(4)复合纳米纤维膜的制备及光催化性能
18
作者 王思新 郑楠 +1 位作者 王宇 董晓丽 《大连工业大学学报》 CAS 2024年第5期364-368,共5页
采用静电纺丝和溶剂热相结合的方法制备了PAN/Cd_(0.8)Zn_(0.2)S/MgIn_(2)S_(4)复合纳米纤维膜,利用DRS、SEM、XRD和电化学测试等表征样品的晶体结构、光学特性和形貌等。通过模拟可见光降解罗丹明B测定了PAN/Cd_(0.8)Zn_(0.2)S/MgIn_(2... 采用静电纺丝和溶剂热相结合的方法制备了PAN/Cd_(0.8)Zn_(0.2)S/MgIn_(2)S_(4)复合纳米纤维膜,利用DRS、SEM、XRD和电化学测试等表征样品的晶体结构、光学特性和形貌等。通过模拟可见光降解罗丹明B测定了PAN/Cd_(0.8)Zn_(0.2)S/MgIn_(2)S_(4)复合纳米纤维膜的光催化活性。结果表明,相比于PAN/Cd_(0.8)Zn_(0.2)S和PAN/MgIn_(2)S_(4),PAN/Cd_(0.8)Zn_(0.2)S/MgIn_(2)S_(4)复合纳米纤维膜展示出了最佳的光催化降解性能,在120min时降解效率可达到96%。制备的PAN/Cd_(0.8)Zn_(0.2)S/MgIn_(2)S_(4)复合纳米纤维膜相比于粉状的半导体光催化剂具备良好的柔性和自支撑性能,在实际应用中易于回收,且可避免二次污染。 展开更多
关键词 静电纺丝 光催化 纳米纤维膜 自支撑 聚丙烯腈
下载PDF
Research on the Internal Talent Training Path and Performance Evaluation Mechanism of New R&D Institutions in Zhejiang Province
19
作者 Xiangjiang Li 《Proceedings of Business and Economic Studies》 2024年第2期100-105,共6页
New research and development(R&D)institutions are an important part of the national innovation system,playing an important role in promoting the transformation of scientific and technological achievements.In recen... New research and development(R&D)institutions are an important part of the national innovation system,playing an important role in promoting the transformation of scientific and technological achievements.In recent years,new R&D institutions have gradually become the driving force of innovation-driven development in China.Taking new R&D institutions in Zhejiang Province as the research object,this paper studies the internal talent training path and performance evaluation mechanism of new R&D institutions in Zhejiang Province by using the literature research method,comparison method,case verification method,and other methods.The investigation results show that there are problems such as lack of material and spiritual support and neglect of the absorption of local talents in the internal talent training,and there are problems such as unclear standards,insufficient data,and opaque processes in the performance evaluation mechanism,which greatly affect the establishment and improvement of the performance evaluation mechanism.Given the above problems,this paper puts forward a forward-looking,oriented,flexible,and compatible talent training path and performance evaluation mechanism,hoping to optimize the effective internal talent training path of new R&D institutions,improve the evaluation performance,and promote healthy development of new R&D institutions in Zhejiang Province. 展开更多
关键词 INNOVATION New R&D institutions zhejiang Province Talent cultivation Performance evaluation mechanism
下载PDF
基于上转换发光的Y_(7)O_(6)F_(9):Er,Yb/PAN复合纤维温度传感特性 被引量:1
20
作者 赵昕 刘哲 +1 位作者 林海 李德胜 《发光学报》 EI CAS CSCD 北大核心 2023年第2期279-288,共10页
通过水热法配合高温煅烧合成了斜方晶系Y_(7)O_(6)F_(9):Er,Yb晶体,该晶体可实现高效上转换发光且具有良好的高分子亲和性。利用高压静电纺丝技术将Y_(7)O_(6)F_(9):Er,Yb晶体颗粒与高分子化合物聚丙烯腈(PAN)复合,制备出了兼备温度传... 通过水热法配合高温煅烧合成了斜方晶系Y_(7)O_(6)F_(9):Er,Yb晶体,该晶体可实现高效上转换发光且具有良好的高分子亲和性。利用高压静电纺丝技术将Y_(7)O_(6)F_(9):Er,Yb晶体颗粒与高分子化合物聚丙烯腈(PAN)复合,制备出了兼备温度传感特性、柔韧性和灵活性的Y_(7)O_(6)F_(9):Er,Yb/PAN纤维。977 nm激光激发下,晶体颗粒和复合纤维在303~433 K温度范围内均展示出高效的上转换发光和良好的温度传感特性,且复合纤维在测温范围内表现出优于晶体颗粒的温度灵敏度和分辨率。在303 K温度下有最大绝对灵敏度值1.143%·K^(-1),在433 K温度下有最小的分辨率0.15 K。因此,具有柔韧性的复合纤维既有良好温度传感特性又可任意调节形态,适应复杂多样的应用环境,是可应用于实现智能穿戴领域温度传感性能的有效候选材料。 展开更多
关键词 Y_(7)O_(6)F_(9):Er Yb/pan复合纤维 高压静电纺丝 上转换发光 温度传感
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部