期刊文献+
共找到441篇文章
< 1 2 23 >
每页显示 20 50 100
Tailoring a Back-Contact Barrier for a Self-Powered Broadband Kesterite Photodetector With Ultralow Dark Current Enabling Ultra-Weak-Light Detection
1
作者 Qianfeng Wu Chuanhao Li +7 位作者 Shuo Chen Zhenghua Su Muhammad Abbas Chao Chen Qianqian Lin Jingting Luo Liming Ding Guangxing Liang 《Carbon Energy》 2025年第5期35-44,共10页
Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by hig... Visible and near-infrared photodetectors are widely used in intelligent driving,health monitoring,and other fields.However,the application of photodetectors in the near-infrared region is significantly impacted by high dark current,which can greatly reduce their performance and sensitivity,thereby limiting their effectiveness in certain applications.In this work,the introduction of a C60 back interface layer successfully mitigated back interface reactions to decrease the thickness of the Mo(S,Se)_(2)layer,tailoring the back-contact barrier and preventing reverse charge injection,resulting in a kesterite photodetector with an ultralow dark current density of 5.2×10^(-9)mA/cm^(2)and ultra-weak-light detection at levels as low as 25 pW/cm^(2).Besides,under a self-powered operation,it demonstrates outstanding performance,achieving a peak responsivity of 0.68 A/W,a wide response range spanning from 300 to 1600 nm,and an impressive detectivity of 5.27×10^(14)Jones.In addition,it offers exceptionally rapid response times,with rise and decay times of 70 and 650 ns,respectively.This research offers important insights for developing high-performance self-powered near-infrared photodetectors that have high responsivity,rapid response times,and ultralow dark current. 展开更多
关键词 DETECTIVITY KESTERITE PHOTODETECTOR thin film weak light detection
在线阅读 下载PDF
Effect of Weak Light on the Peroxidation of Membrane_Lipid of Cherry Leaves 被引量:23
2
作者 黄卫东 吴兰坤 战吉 《Acta Botanica Sinica》 CSCD 2002年第8期920-924,共5页
The effect of weak light on the peroxidation of membrane_lipid of one_year_old cherries ( Prunus pseudocerasus L. 'Laiyang') was studied by whole_tree shading. The results showed that the net photosynthetic... The effect of weak light on the peroxidation of membrane_lipid of one_year_old cherries ( Prunus pseudocerasus L. 'Laiyang') was studied by whole_tree shading. The results showed that the net photosynthetic rate of cherry leaves under weak light was remarkably lower; the activity peroxidase (POD) increased when light intensity decreased; the activity of catalase (CAT) showed an opposite trend, and it was positively correlated with light intensity; the activity of superoxide dismutase (SOD) increased under 366 μmol·m -2 ·s -1 and 533.8 μmol·m -2 ·s -1 light intensity, but decreased under 228.8 μmol·m -2 ·s -1 and 83.9 μmol·m -2 ·s -1 light intensity. A remarkable increase of malondialdehyde (MDA), a product of membrane_lipid peroxidation, was also observed in cherry leaves when treated with weak light, indicating more serious peroxidation in the membrane. 展开更多
关键词 weak light CHERRY membrane_lipid peroxidation membrane_protecting enzyme
在线阅读 下载PDF
Effects of Weak Light on the Ultrastructural Variations of Phloem Tissues in Source Leaves of Three-Year-Old Nectarine Trees(Prunus persica L.var. nectarina Ait.) 被引量:6
3
作者 王秀芹 黄卫东 《Acta Botanica Sinica》 CSCD 2003年第6期688-697,共10页
Leaves from three_year_old solar greenhouse nectarine trees ( Prunus persica L. var. nectarina Ait. “Zao Hong Yan”) were used as materials in this study. It was the first time that the ultrastructural charact... Leaves from three_year_old solar greenhouse nectarine trees ( Prunus persica L. var. nectarina Ait. “Zao Hong Yan”) were used as materials in this study. It was the first time that the ultrastructural characteristics of phloem tissues of source leaves were observed and compared in normal and weak light intensities using the transmission electron microscopy. Results showed that the average diameters of companion cells (CC) and sieve elements (SE) of all kinds of veins were bigger in normal than that in weak light intensity, indicating that light could influence the cell development and growth. Dense cytoplasm with abundant mitochondria, endoplasmic reticulums, multivesicular bodies, vesicles and plastids were observed in normal light intensity. On the contrary, CC with small vacuolar structures and few mitochondrias, endoplasmic reticulums were shown in weak light. Misalignment of grana thylakoid margins of nectarine leaves also was seen in weak light. The sieve pores of SEs were obstructed in weak light. Chloroplasts with numerous starch grains and few mitochondrias were noticed in the mesophyll cell (MES) surrounding the bundle sheath in weak light. The storage of starch grains appeared to result from an unbalance between photosynthate production and export of photosynthates. This observation provided a strong support to the point that most leaves export the most of assimilates in the light time. Plasmodesmal densities between SE/CC, CC/PP (phloem parenchyma cell), PP/PP and PP/BSC (bundle_sheath cell) decreased in weak light. Plasmodesmata were observed between CC/SE (NS) (nacreous_walled sieve element), PP/BSC in branch veins in normal light intensity, but not in weak light. Thus apoplasmic pathway may be the main mode of transport of assimilates in weak light, however symplasmic pathway may be the main mode of transport of assimilates in normal light intensity. These results demonstrated that the solar greenhouse nectarine trees could be adapted to the weak light via the ultrastructure variation of phloem tissues of the source leaves. 展开更多
关键词 nectarine (Prunus persica L.var. nectarina Ait.) phloem tissue ultrastructure weak light SE/CC complex phloem loading
在线阅读 下载PDF
Effects of Weak Light on Starch Accumulation and Starch Synthesis Enzyme Activities in Rice at the Grain Filling Stage 被引量:8
4
作者 LI Tian Ryu OHSUGI +1 位作者 Tohru YAMAGISHI Haruto SASAKI 《Rice science》 SCIE 2006年第1期51-58,共8页
Dynamic changes of starch, amylose, sucrose contents and the activities of starch synthesis enzymes under shading treatments alter flowering were studied using two rice varieties IR72 (indica) and Nipponbare (japon... Dynamic changes of starch, amylose, sucrose contents and the activities of starch synthesis enzymes under shading treatments alter flowering were studied using two rice varieties IR72 (indica) and Nipponbare (japonica) as materials. Under shading treatments, the starch, amylose and sucrose contents decreased, while ADP-glucose pyrophosphorylase (ADPGPPase) activity only changed a little, soluble starch synthase activity and granule bound starch synthase activity decreased, soluble starch branching enzyme (SSBE, Q-enzyme) activity and granule bound starch branching enzyme (GBSBE, Q-enzyme) activity increased, and starch debranching enzyme (DBE, R-enzyme) activity varied with varieties. Correlation analyses showed that the changes of starch content were positively and significantly correlated with the changes of sucrose content in the weak light. Both ADPGPPase activity and SSBE activity were positively and significantly correlated with starch accumulation rate. It was implied that the decline of starch synthase activities was related to the decrease of starch content and the increase of the activity of starch branching enzyme played an important role in the decrease of the ratio of amylose to the total starch under the weak light. 展开更多
关键词 weak light starch content ADP-glucose pyrophosphorylase starch synthase starch branching enzyme starch debranching enzyme RICE
在线阅读 下载PDF
Accumulation and Gene Expression of Anthocyanin in Storage Roots of Purple-Freshed Sweet Potato [Ipomoea batatas (L.) Lam] Under Weak Light Conditions 被引量:13
5
作者 HOU Fu-yun WANG Qing-mei +4 位作者 DONG Shun-xu LI Ai-xian ZHANG Hai-yan XIE Bei-tao ZHANG Li-ming 《Agricultural Sciences in China》 CSCD 2010年第11期1588-1593,共6页
Anthocyanidin in plants, an important pigment, is of great interest to researchers, consumers, and commercial entities due to its physiological functions. Anthocyanin content and mRNA levels of anthocynin biosynthesis... Anthocyanidin in plants, an important pigment, is of great interest to researchers, consumers, and commercial entities due to its physiological functions. Anthocyanin content and mRNA levels of anthocynin biosynthesis genes were investigated in storage root of different purple-fleshed sweet potatoes (PFSP) genotypes to understand the regulation mechanism of anthocyanin under weak light conditions. Anthocyanin content, its amount of accumulation, and the expression of CHS, DFR, F3H, GT, and ANS genes in the PFSP storage root under weak light conditions were studied. The results demonstrated that the anthocyanin content of the treatments was decreased and was obviously lower than that of the control until 30 days after shading in Ayamurasaki, while it was lower than that of the control from the beginning of shading in Jishu 18. Their accumulation rates of both treatmeants were lower than its control before 10-20 d of shading in Jishu 18, while those of Ayamurasaki weren't in their treatments. This indicated that Jishul 8 is more sensitive to light as compared to Ayamuraska. Under the different weak light conditions, mRNA levels for ibCHS, ibF3H, ibDFR, and ibANS were obviously decreased, while the expression of ibGT was increased. These results indicated that anthocyanin content was regulated by light at the mRNA levels and the enzymatic level in sweet potato. Therefore, the development dynamic response to anthocyanin content varied in different genotypes of PFSP, and mRNA levels of anthocyanin biosynthesis were inhibited under the weak light condition. 展开更多
关键词 anthocynin sweet potato storage root weak light
在线阅读 下载PDF
Effect of Weak Light on the Photoassimilates Distribution and Transformation of Young Grape Plants 被引量:3
6
作者 ZHAN Ji-cheng, HUANG Wei-dong and WANG Li-jun(College of Horticultural Sciences , China Agricultural University, Beijing 100094 , P. R . China) 《Agricultural Sciences in China》 CAS CSCD 2002年第9期1006-1011,共6页
The effect of weak light on the photoassimilates distribution and transformation of young Jingyu grape plants ( Vitis vinefera L. cv. Jingyu) were studied by shading. Compared to the grape grown under natural light in... The effect of weak light on the photoassimilates distribution and transformation of young Jingyu grape plants ( Vitis vinefera L. cv. Jingyu) were studied by shading. Compared to the grape grown under natural light intensity environment, the net photosynthetic rate diurnal variation curve of experimental plants grown in weak light intensity environment was remarkably lower. Its leaf and stem biomass ratio increased when light intensity decreased, the root and new shoot biomass ratio showed an opposite trend. The 14 C-photoassimilates was mostly distributed to young leaves and stem, a little was distributed to root. The metabolism of 14C-photoassimilates distributed to the entire grape body were also changed under weak light intensity environment. 展开更多
关键词 weak light Net photosynthetic rate(Pn) Biomass partition Photoassimilates distribution Photoassimilates transformation
在线阅读 下载PDF
Spatial weak-light ring soliton in self-assembled quantum dots 被引量:1
7
作者 陈秋成 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第12期235-239,共5页
By using semiclassical theory combined with multiple-scale method, we analytically study the linear absorption and the nonlinear dynamical properties in a lifetime broadened Λ-type three-level self-assembled quantum ... By using semiclassical theory combined with multiple-scale method, we analytically study the linear absorption and the nonlinear dynamical properties in a lifetime broadened Λ-type three-level self-assembled quantum dots. It is found that this system can exhibit the transparency, and the width of the transparency window becomes wider with the increase of control light field. Interestingly, a weak probe light beam can form spatial weak-light dark solitons. When it propagates along the axial direction, the soliton will transform into a steady spatial weak-light ring dark soltion. In addition, the stability of two-dimensional spatial optical solitons is testified numerically. 展开更多
关键词 spatial weak-light ring dark soliton electromagnetically induced transparency self-assembled quantum dots
原文传递
基于FPGA的轻量化自适应ORB算法研究与实现
8
作者 王鼎轩 姚荣彬 +1 位作者 赵中华 李晓欢 《现代电子技术》 北大核心 2026年第1期117-123,共7页
为了解决ORB算法计算复杂、实时性差以及算法固定阈值在光照变化及低纹理场景下特征检测不足的问题,文中提出一种基于FPGA的轻量化自适应ORB算法加速架构。首先,对ORB算法的特征方向计算进行改进,采用了一种基于区域划分的特征方向角度... 为了解决ORB算法计算复杂、实时性差以及算法固定阈值在光照变化及低纹理场景下特征检测不足的问题,文中提出一种基于FPGA的轻量化自适应ORB算法加速架构。首先,对ORB算法的特征方向计算进行改进,采用了一种基于区域划分的特征方向角度和描述符计算方法,减少了计算资源消耗,结合FPGA的并行化和流水线计算优势,设计了一种轻量化ORB加速架构;其次,在原有算法的基础上加入直方图均衡算法,调整图像亮度,提高图像的对比度,使图像的特征细节更加明显;最后,针对ORB算法的固定阈值,设计了一种自适应阈值计算方法,实现了算法在弱光照和低纹理场景下提取特征点数量的提升。实验结果表明:相对于软件的算法实现,基于FPGA的硬件加速架构能够得到16.1倍的加速效果,在弱光照和低纹理条件下提取特征点数量分别是ORB算法的6.67倍和2.56倍,特征匹配点对数量分别是ORB算法的5.62倍和1.5倍。实现了算法的加速和资源消耗的降低,提升了算法的自适应性以及在不同场景的鲁棒性。 展开更多
关键词 ORB 特征检测 FPGA 轻量化 直方图均衡 自适应阈值 弱光照 低纹理
在线阅读 下载PDF
日光温室番茄苗期低温寡照灾变过程及其影响机制
9
作者 麻雪艳 宫志宏 +3 位作者 刘涛 尹紫薇 李根 王天宁 《气象与环境科学》 2026年第1期1-10,共10页
为深入了解低温寡照致灾过程,提高设施作物低温寡照灾害应对能力,保障国家设施农业生产安全,以天津市日光温室番茄为研究对象,在苗期开展持续10天的低温寡照模拟试验,共设置5种温度水平和2种光照水平,形成5个不同强度的低温寡照处理,分... 为深入了解低温寡照致灾过程,提高设施作物低温寡照灾害应对能力,保障国家设施农业生产安全,以天津市日光温室番茄为研究对象,在苗期开展持续10天的低温寡照模拟试验,共设置5种温度水平和2种光照水平,形成5个不同强度的低温寡照处理,分别为T1(25℃/18℃,200μmol·m^(-2)·s^(-1))、T2(22℃/15℃,200μmol·m^(-2)·s^(-1))、T3(18℃/11℃,200μmol·m^(-2)·s^(-1))、T4(15℃/8℃,200μmol·m^(-2)·s^(-1))和T5(12℃/5℃,200μmol·m^(-2)·s^(-1)),另设一组正常温光对照CK(25℃/18℃,800μmol·m^(-2)·s^(-1)),从灾变过程入手,分析不同强度低温寡照条件下番茄苗期的灾变过程及其可能的影响机制。结果表明,随着低温寡照强度的增加和持续时间的延长,对番茄生长发育指标的抑制作用增加,最终影响番茄的产量和果实品质。但是番茄不同生长指标响应低温胁迫的敏感性不同,不同生长指标对低温寡照的响应次序为叶片光合作用、叶面积、叶干重、茎干重、株高、根干重,番茄各器官对低温寡照的敏感程度由高至低依次为叶、茎、根。基于结构方程模型探讨了低温寡照对番茄生长发育的影响机制:温度会直接影响番茄叶面积的生长,而光照会直接影响番茄叶片生物量的积累,进而间接影响番茄叶面积的扩展,导致茎、根器官生物量积累减少、生长速率降低,最终导致产量和果实品质降低。 展开更多
关键词 番茄 低温 寡照 灾变过程 结构方程模型
在线阅读 下载PDF
灌浆前期低温弱光复合处理对水稻产量和品质的影响 被引量:2
10
作者 胡雅杰 郭靖豪 +7 位作者 丛舒敏 蔡沁 徐益 孙亮 郭保卫 邢志鹏 杨文飞 张洪程 《作物学报》 北大核心 2025年第2期405-417,共13页
以软米粳稻南粳9108和常规粳稻淮稻5号为供试材料,通过人工气候室设置梯度温度模拟水稻灌浆前期(齐穗至穗后20d)温度动态递减变化,设置灌浆前期动态低温和低温弱光处理,并以室外温光作为对照(CK),研究灌浆前期低温弱光对水稻产量及其构... 以软米粳稻南粳9108和常规粳稻淮稻5号为供试材料,通过人工气候室设置梯度温度模拟水稻灌浆前期(齐穗至穗后20d)温度动态递减变化,设置灌浆前期动态低温和低温弱光处理,并以室外温光作为对照(CK),研究灌浆前期低温弱光对水稻产量及其构成、干物质生产和稻米品质的影响。结果表明:与CK相比,灌浆前期低温和低温弱光处理均降低水稻产量,低温弱光处理减产显著。灌浆前期低温弱光处理降低结实率和千粒重导致减产;低温处理降低结实率,而千粒重有所增加。与CK相比,灌浆前期低温和低温弱光处理均降低水稻成熟期干物质重和穗部干重,叶和茎鞘干物质积累量较高;倒一叶、倒二叶和倒三叶SPAD值均呈上升趋势,表现为低温弱光>低温>CK;剑叶的过氧化氢酶(CAT)、过氧化物酶(POD)和超氧化物歧化酶(SOD)活性呈先增加后降低趋势,抗坏血酸过氧化物酶(APX)活性呈增加,丙二醛(MDA)含量和H_(2)O_(2)含量较高。就稻米品质而言,与CK相比,灌浆前期低温处理下稻米加工品质和外观品质变优,而低温弱光处理下稻米加工品质变劣。与CK相比,灌浆前期低温处理下直链淀粉含量增加,胶稠度下降,蛋白质含量降低,食味值降低;而低温弱光处理下直链淀粉含量降低,胶稠度下降,蛋白质含量增加,食味值降低。因此,灌浆前期低温和低温弱光均降低稻米食味品质。 展开更多
关键词 水稻 灌浆前期 低温弱光 产量 品质
在线阅读 下载PDF
Effects of Formaldehyde and Low-light Stress on Growth and Nutrition of Hedera spp.
11
作者 Yongfu ZHANG Shengjing PENG Yanfen NIU 《Agricultural Biotechnology》 CAS 2018年第5期48-53,57,共7页
Potted seedlings of Hedera nepalensis and H. helix were exposed to formaldehyde and low light alone or in combination for four months, before the morphological and nutritive indices of the plants were measured to asse... Potted seedlings of Hedera nepalensis and H. helix were exposed to formaldehyde and low light alone or in combination for four months, before the morphological and nutritive indices of the plants were measured to assess the effects of formaldehyde and low-light stress on the growth and nutrient accumulation of Hedera species. The results showed that treatment with either formaldehyde or low-light stress reduced leaf length, leaf width, stem length, stem diameter, root length and biomass, but increased leaf shape index of the two Hedera species. Treatment with formaldehyde alone increased root-shoot ratio, while treatment with formaldehyde + low light or low light alone decreased root-shoot ratio of the two Hedera species. Under the stress of formaldehyde, soluble sugar content decreased, while starch content increased in roots, stems and leaves of the two Hedera species; total carbon content, proline content and carbon-to-nitrogen (C/N) ratio increased, while protein content and phosphorus content decreased in roots of the two Hedera species; the contents of total carbon, protein and total nitrogen in leaves of the two Hedera species; C/N ratio in roots of H. nepalensis increased; the C/N ratio in roots of H. nepalensis and that in leaves of the two Hedera species significantly increased. Under formaldehyde + low light stress, the soluble sugar content decreased, while starch content increased in stems and leaves of the two Hedera species; starch content in roots of the two Hedera species decreased; the contents of protein and total nitrogen decreased, while C/N ratio increased in leaves of H. nepalensis ; proline content in roots and stems of the two Hedera species significantly increased. 展开更多
关键词 Hedera spp. FORMALDEHYDE weak light GROWTH NUTRITION
在线阅读 下载PDF
空间定位与特征泛化增强的铁路异物跟踪检测 被引量:2
12
作者 陈永 王镇 周方春 《北京航空航天大学学报》 北大核心 2025年第1期9-18,共10页
针对现有深度学习异物跟踪检测算法易受复杂环境、目标遮挡等影响,导致出现漏检及检测精度低等问题,提出了一种空间定位与特征泛化增强的铁路异物跟踪检测算法。提出改进多尺度级联GhostNet特征提取网络,提升对红外目标的特征提取能力;... 针对现有深度学习异物跟踪检测算法易受复杂环境、目标遮挡等影响,导致出现漏检及检测精度低等问题,提出了一种空间定位与特征泛化增强的铁路异物跟踪检测算法。提出改进多尺度级联GhostNet特征提取网络,提升对红外目标的特征提取能力;利用异物空间位置定位与泛化形态信息,设计空间定位与特征泛化增强模块,增强对复杂场景下位置移动与跟踪轨迹变化目标的检测精度;构建金字塔预测网络,得到红外铁路异物的检测锚框、类别及置信度信息;通过改进类别和置信度显示的DeepSORT跟踪算法,结合卡尔曼滤波与匈牙利算法实现红外弱光环境下铁路异物跟踪检测。实验结果表明:所提算法对铁路异物的跟踪检测精确度达到83.3%,平均检测速度为11.3帧/s;与比较算法相比,所提算法检测精度更高,对红外弱光场景下铁路异物跟踪检测具有较好的性能。 展开更多
关键词 机器视觉 异物检测 红外弱光 空间定位 特征泛化增强 目标跟踪
原文传递
厚皮甜瓜新品种‘金种缘金甜’
13
作者 田红梅 王元龙 +4 位作者 王飞 潘弘 陶珍 张建 王朋成 《园艺学报》 北大核心 2025年第S1期153-154,共2页
‘金种缘金甜’是以XD-001为母本、以XD-005为父本杂交选育而成的厚皮甜瓜新品种。全生育期96 d左右,果实发育期36 d左右。果实椭圆形,果皮黄色,上覆10~12条银色淡绿凹沟,果面光滑亮丽,果肉橙色,肉质细嫩甜脆,香味浓郁;中心可溶性固形... ‘金种缘金甜’是以XD-001为母本、以XD-005为父本杂交选育而成的厚皮甜瓜新品种。全生育期96 d左右,果实发育期36 d左右。果实椭圆形,果皮黄色,上覆10~12条银色淡绿凹沟,果面光滑亮丽,果肉橙色,肉质细嫩甜脆,香味浓郁;中心可溶性固形物含量17.4%左右;平均单果质量1.51 kg,每公顷产量达65 700 kg;抗白粉病、霜霉病,耐低温弱光。适宜安徽、山东、河南、江苏、浙江、陕西、甘肃春季及秋延种植。 展开更多
关键词 甜瓜 橙肉 耐低温弱光 品种
原文传递
基于多任务联合学习的弱光场景人脸检测算法
14
作者 张霞 苏昭辉 陈路 《计算机科学》 北大核心 2025年第2期191-201,共11页
弱光场景中的人脸检测指在弱光条件下使用图像处理技术检测人脸。目前,大多数弱光环境下的人脸检测算法通常先将弱光图像进行增强再进行人脸检测,忽略了人脸检测和图像增强任务之间的特征相关性,从而影响了模型泛化能力。受EnlightenGA... 弱光场景中的人脸检测指在弱光条件下使用图像处理技术检测人脸。目前,大多数弱光环境下的人脸检测算法通常先将弱光图像进行增强再进行人脸检测,忽略了人脸检测和图像增强任务之间的特征相关性,从而影响了模型泛化能力。受EnlightenGAN算法的启发,文中提出一种适用于弱光环境人脸检测的多任务联合学习算法:首先融合人脸检测和图像增强的输入层共享表示;其次将人脸注意力网络和EnlightenGAN相结合,在全局-局部判别器的基础上增加用于人脸区域判定的局部判别器;最后在自正则化注意力图的基础上增加光照权重参数,通过调节使人脸检测的精度达到最佳值。在DARK FACE数据集上的实验结果表明,与现有算法相比,所提算法的人脸检测精度提升了1.92%,同时能够很好地提升弱光图像视觉质量。 展开更多
关键词 弱光环境 人脸检测 图像增强 多任务联合学习 局部判别器
在线阅读 下载PDF
面向单目可见光环境的自适应双手重建网络
15
作者 廖国琼 黄龙杰 +2 位作者 李清新 辜勇 李海波 《图学学报》 北大核心 2025年第4期837-846,共10页
准确重建双手手部网格对于自然的人机交互体验来说是一个至关重要的过程,但由于双手的遮挡、户外收集双手交互数据集的复杂性和复杂的光照环境干扰等因素导致双手手部重建任务仍极具挑战性。目前已有的工作大多是在环境干扰比较小的实... 准确重建双手手部网格对于自然的人机交互体验来说是一个至关重要的过程,但由于双手的遮挡、户外收集双手交互数据集的复杂性和复杂的光照环境干扰等因素导致双手手部重建任务仍极具挑战性。目前已有的工作大多是在环境干扰比较小的实验室等场景下取得的的良好效果,而在复杂的光照场景中的重建效果仍不佳。为了解决上述问题,提出一种面向单目可见光环境的自适应手部重建网络。通过引入单手检测框和使用2D复杂光照场景数据集进行弱监督等策略使得模型得以对复杂光照场景产生泛化性;设计的双手特征交互器得以有效建立左右手特征的远距离依赖关系,缓解了单手检测框缺乏双手交互信息的问题;针对如何有效融合交互特征与单手特征的问题,设计了自适应融合的策略,增强了模型的鲁棒性。实验结果表明,在包含多个复杂光照场景的HIC数据集中取得了最佳的效果。 展开更多
关键词 复杂光照场景 手部网格 双手交互 弱监督 特征融合
在线阅读 下载PDF
微带谐振法弱光信号检测技术研究 被引量:1
16
作者 李亚峰 李恩 穆仕博 《中国测试》 北大核心 2025年第4期160-167,共8页
以光与微波互作用机理为基础,结合微波谐振法检测技术准确度高、响应快以及灵敏度高等特点,提出一种基于微带谐振法的弱光信号检测新技术。与传统将光信号转化为电信号进行检测不同,将硫化镉(CdS)光敏电阻加载在微带谐振环开口处,使CdS... 以光与微波互作用机理为基础,结合微波谐振法检测技术准确度高、响应快以及灵敏度高等特点,提出一种基于微带谐振法的弱光信号检测新技术。与传统将光信号转化为电信号进行检测不同,将硫化镉(CdS)光敏电阻加载在微带谐振环开口处,使CdS敏化材料的光敏特性与微带测试传感器的微波谐振特性相结合,实现将弱光信号检测转变为微波信号进行检测。测试结果表明:采用该微带谐振环传感器可实现对红光、绿光和蓝紫光的最低可检测功率分别为Pred=7.5×10^(–9)W,Pgreen=1.1×10^(–8)W,Pblue=2.5×10^(–8)W,响应灵敏度分别为Rred=0.015 dB/nW,Rgreen=0.0027 dB/nW,Rblue=0.0025 dB/nW,噪声等效功率分别为NEPred=8.38×10^(–11)W/Hz1/2,NEPgreen=1.23×10^(–10)W/Hz1/2,NEPblue=2.8×10^(–10)W/Hz1/2,即微带谐振法测试系统可实现对弱光信号的高灵敏检测。此外,3种单色光在最低可测功率的5次重复性实验中,测试系统的最大测试误差≤0.18%,可验证测试系统的稳定性。 展开更多
关键词 微波谐振法 微带谐振环 硫化镉 弱光检测
在线阅读 下载PDF
61份西瓜种质苗期耐弱光性研究
17
作者 尚文凯 刘勇鹏 +7 位作者 骆恒斌 马肖静 韩亚伟 李晓慧 王永 朴凤植 张涛 赵卫星 《山东农业科学》 北大核心 2025年第2期38-47,共10页
本研究以61份西瓜种质为试验材料,在室内设置200μmol·m^(-2)·s^(-1)和60μmol·m^(-2)·s^(-1)的LED光强处理,通过测定不同西瓜种质幼苗的13个性状指标及运用相关性分析、主成分分析、隶属函数分析、聚类分析等多元... 本研究以61份西瓜种质为试验材料,在室内设置200μmol·m^(-2)·s^(-1)和60μmol·m^(-2)·s^(-1)的LED光强处理,通过测定不同西瓜种质幼苗的13个性状指标及运用相关性分析、主成分分析、隶属函数分析、聚类分析等多元分析方法对其进行耐弱光性综合评价。结果表明,弱光(60μmol·m^(-2)·s^(-1)光强)胁迫下,61份西瓜种质幼苗的株高、茎粗、叶宽、叶长、叶柄长度、地上部地下部干鲜重及根系各性状的变异系数均超过对照(200μmol·m^(-2)·s^(-1)光强),且两者间存在显著的遗传差异性;其次,13个性状的耐弱光系数均存在不同程度的相关性,综合影响着西瓜幼苗的耐弱光能力;通过主成分分析将西瓜13个性状耐弱光系数指标转化为4个相互独立的综合指标,其累计贡献率达到80.48%;通过隶属函数分析并按D值大小进行聚类分析,将61份种质分成4类,其中Ⅰ类极耐弱光性种质1份、Ⅱ类耐弱光性种质22份、Ⅲ类中耐弱光性种质7份、Ⅳ类弱光敏感性种质31份;筛选出的耐弱光性最强种质为HY-25、HY-90和HY-81。本研究结果可为筛选西瓜耐弱光性鉴定指标、科学评价西瓜种质的耐弱光性提供参考依据。 展开更多
关键词 西瓜 苗期 耐弱光性 隶属函数 聚类分析
在线阅读 下载PDF
辣椒耐低温弱光研究进展
18
作者 马玲玲 SHAMS Shamsullah +7 位作者 李戎轩 NAEEM Beenish 张正海 曹亚从 于海龙 冯锡刚 吴华茂 王立浩 《园艺学报》 北大核心 2025年第8期2155-2165,共11页
低温弱光胁迫是中国冬季辣椒保护地栽培主要的限制因子之一,影响辣椒的产量和品质。本文综述了辣椒在耐低温、弱光及低温弱光双重胁迫条件下的国内外研究进展,总结了辣椒在应对胁迫时的生理(生长、生理生化和光合特性)和分子机制的响应... 低温弱光胁迫是中国冬季辣椒保护地栽培主要的限制因子之一,影响辣椒的产量和品质。本文综述了辣椒在耐低温、弱光及低温弱光双重胁迫条件下的国内外研究进展,总结了辣椒在应对胁迫时的生理(生长、生理生化和光合特性)和分子机制的响应,并展望了辣椒耐低温弱光双重胁迫的研究前景。 展开更多
关键词 辣椒 低温 弱光 胁迫 机制 综述
原文传递
融合颜色恒常性和多尺度小波的弱光照图像细节增强
19
作者 刘巧玲 刘玲 喻娜 《激光杂志》 北大核心 2025年第4期115-120,共6页
光照不足易导致图像细节丢失,影响图像的检测和分析。为此,提出一种融合颜色恒常性与多尺度小波技术的弱光照图像细节增强方法。利用B样条曲线精准校正色彩偏差,通过四叉树空间索引与暗通道先验技术实现场景深度重构。应用大气散射模型... 光照不足易导致图像细节丢失,影响图像的检测和分析。为此,提出一种融合颜色恒常性与多尺度小波技术的弱光照图像细节增强方法。利用B样条曲线精准校正色彩偏差,通过四叉树空间索引与暗通道先验技术实现场景深度重构。应用大气散射模型来复原低频无雾图像,并通过梯度增强提升去雾图像的纹理细节。引入多尺度小波重构技术生成清晰的图像。从输出图像中提取光照权重矩阵,并利用该矩阵完成光照分量的初始估计。在光照结构的约束下,优化估计初始光照分量。通过非线性光照调整进一步优化光照效果,结合Retinex模型增强弱光照图像的细节表现力。实验结果表明,所提方法增强处理后的弱光照图像细节方面更加丰富且清晰。 展开更多
关键词 融合颜色恒常性 多尺度小波 弱光照图像 细节增强
原文传递
花后弱光对软质小麦干物质积累转运、籽粒产量和淀粉品质的影响
20
作者 杨婷婷 陈娟 +4 位作者 ABDUL Rehman 李婧 闫素辉 汪建来 李文阳 《作物学报》 北大核心 2025年第8期2204-2219,共16页
探究花后弱光对软质小麦干物质积累转运、籽粒产量和淀粉品质的影响,为江淮地区软质小麦抗逆优质丰产栽培技术提供参考。于2022—2024年度,在大田条件下,以软质小麦品种荃麦725(QM725)和扬麦15(YM15)为材料,试验于小麦灌浆期(开花后7~35... 探究花后弱光对软质小麦干物质积累转运、籽粒产量和淀粉品质的影响,为江淮地区软质小麦抗逆优质丰产栽培技术提供参考。于2022—2024年度,在大田条件下,以软质小麦品种荃麦725(QM725)和扬麦15(YM15)为材料,试验于小麦灌浆期(开花后7~35 d)设置3个遮光处理,即遮光10%(S1)、遮光20%(S2)和遮光30%(S3),以自然光照条件作为对照(CK)。研究花后弱光胁迫对软质小麦干物质积累转运、籽粒产量和淀粉品质形成的影响。结果表明,与对照(CK)相比,花后弱光显著增加了花前器官同化物的转运量、转运率以及对籽粒的贡献率,减少了花后光合同化物的积累量以及籽粒贡献率。花后不同弱光处理后,显著降低了小麦穗粒数和千粒重,进而导致籽粒产量降低,且在各处理下,虽提高了小麦籽粒蛋白质含量,但显著降低了籽粒淀粉含量、籽粒蛋白质和淀粉积累量。花后弱光胁迫下,显著降低了软质小麦B型淀粉粒(粒径≤10.0μm)体积、表面积和数目百分比,增加了A型淀粉粒(粒径>10.0μm)体积、表面积百分比,对软质小麦籽粒A型淀粉粒数目百分比无显著影响,只有年份间差异显著。在B型淀粉粒中,弱光对粒径0.1~2.8μm淀粉粒体积百分比的影响大于2.8~10.0μm淀粉粒。在A型淀粉粒中,弱光对粒径>22.0μm淀粉粒体积百分比的影响大于10.0~22.0μm淀粉粒。不同程度弱光处理下,小麦峰值黏度、低谷黏度、最终黏度等糊化特性均显著降低,且虽提高了淀粉热焓值参数,但显著降低了起始温度、峰值温度和终止温度。花后弱光显著影响了小麦干物质积累、转运以及对籽粒的贡献率,并降低了小麦穗粒数、千粒重和籽粒产量,虽提高了籽粒蛋白质含量,但显著降低了籽粒淀粉含量,从而影响了小麦籽粒产量的形成。随着花后光照强度的降低,对B型淀粉粒的影响大于A型淀粉粒,即B型淀粉粒体积、表面积和数目占比降低,A型淀粉粒体积和表面积占比增加,小麦峰值黏度等糊化参数、起始温度、峰值温度和终止温度等显著降低,最终影响小麦籽粒品质。 展开更多
关键词 软质小麦 弱光 干物质积累转运 籽粒产量 粒度分布 糊化特性
在线阅读 下载PDF
上一页 1 2 23 下一页 到第
使用帮助 返回顶部