针对小尺度目标在检测时精确率低且易出现漏检和误检等问题,提出一种改进的YOLOv3(You Only Look Once version 3)小目标检测算法。在网络结构方面,为提高基础网络的特征提取能力,使用DenseNet-121密集连接网络替换原Darknet-53网络作...针对小尺度目标在检测时精确率低且易出现漏检和误检等问题,提出一种改进的YOLOv3(You Only Look Once version 3)小目标检测算法。在网络结构方面,为提高基础网络的特征提取能力,使用DenseNet-121密集连接网络替换原Darknet-53网络作为其基础网络,同时修改卷积核尺寸,进一步降低特征图信息的损耗,并且为增强检测模型对小尺度目标的鲁棒性,额外增加第4个尺寸为104×104像素的特征检测层;在对特征图融合操作方面,使用双线性插值法进行上采样操作代替原最近邻插值法上采样操作,解决大部分检测算法中存在的特征严重损失问题;在损失函数方面,使用广义交并比(GIoU)代替交并比(IoU)来计算边界框的损失值,同时引入Focal Loss焦点损失函数作为边界框的置信度损失函数。实验结果表明,改进算法在VisDrone2019数据集上的均值平均精度(mAP)为63.3%,较原始YOLOv3检测模型提高了13.2百分点,并且在GTX 1080 Ti设备上可实现52帧/s的检测速度,对小目标有着较好的检测性能。展开更多
Three members of the angiopoietin-like(ANGPTL) protein family-ANGPTL3, ANGPTL4 and ANGPTL8-are important regulators of plasma lipoproteins. They inhibit the enzyme lipoprotein lipase, which plays a key role in the int...Three members of the angiopoietin-like(ANGPTL) protein family-ANGPTL3, ANGPTL4 and ANGPTL8-are important regulators of plasma lipoproteins. They inhibit the enzyme lipoprotein lipase, which plays a key role in the intravascular lipolysis of triglycerides present in some lipoprotein classes. This review focuses on the role of ANGPTL3 as emerged from the study of genetic variants of Angptl3 gene in mice and humans. Both loss of function genetic variants and inactivation of Angptl3 gene in mice are associated with a marked reduction of plasma levels of triglyceride and cholesterol and an increased activity of lipoprotein lipase and endothelial lipase. In humans with ANGPTL3 deficiency, caused by homozygous loss of function(LOF) variants of Angptl3 gene, the levels of all plasma lipoproteins are greatly reduced. This plasma lipid disorder referred to as familial combined hypolipidemia(FHBL2) does not appear to be associated with distinct pathological manifestations. Heterozygous carriers of LOF variants have reduced plasma levels of total cholesterol and triglycerides and are at lower risk of developing atherosclerotic cardiovascular disease, as compared to non-carriers. These observations have paved the way to the development of strategies to reduce the plasma level of atherogenic lipoproteins in man by the inactivation of ANGPTL3, using either a specific monoclonal antibody or anti-sense oligonucleotides.展开更多
NRL3 is essential for the growth and development of rice leaves.In this study,we found that the loss function of NRL3 also delayed heading date under natural long daylight and short daylight conditions.The yeast two-h...NRL3 is essential for the growth and development of rice leaves.In this study,we found that the loss function of NRL3 also delayed heading date under natural long daylight and short daylight conditions.The yeast two-hybrid and the bimolecular fluorescence complementation proved that NRL3interacts with OsK4,a Snf1-related kinase.OsK4 localized to the nucleus and expressed in various rice tissues.The rhythmic expression pattern of Os K4 was similar to NRL3 under long daylight and short daylight conditions.Knock-out mutants of Os K4 exhibited early heading under long daylight conditions,indicating that it acts as a negative regulator of heading date in rice.Interestingly,the OsK4 mutant under the nrl3 mutant background rescued the late heading phenotype of nrl3 under long daylight conditions,suggesting that Os K4 functions downstream of NRL3.Moreover,both NRL3 and Os K4 controlled heading date through regulating the expression of Hd3a and RFT1 genes.These findings shed light on the heading date regulation in rice and provide a sound theoretical base to improve regional adaptability of rice.展开更多
In this work the electronic structure and the impurity excess of the basal and rhombohedral twin grain boundaries are investigated, using electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectrosco...In this work the electronic structure and the impurity excess of the basal and rhombohedral twin grain boundaries are investigated, using electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDXS). The measurability of electronic structures of the twin grain boundaries are discussed by comparing theoretical density of states (DOS) from bulk material with interfacial DOS, obtained from local density functional theory (LDFT) calculations.展开更多
High-frequency magnetic materials are crucial for realizing anti-electromagnetic interference in GHz communication devices and electronic equipment.Current mainstream strategy to enhance highfrequency magnetic losses ...High-frequency magnetic materials are crucial for realizing anti-electromagnetic interference in GHz communication devices and electronic equipment.Current mainstream strategy to enhance highfrequency magnetic losses is shape anisotropy,and it is still difficult to obtain an improvement in intrinsic magnetic loss through electronic structure design.In this paper,the effects of 4f-3d interaction between Er and Fe/Co on magnetic moment,charge migration,and spin polarization were investigated based on density functional theory(DFT).The results show that Er 4f-Fe 3d orbitals undergo significant hybridization at around-4 eV,which increase the electronic locality of Fe and enhance the spin of Fe from 2.86 h/2 to 2.91 h/2.The Fe_(0.5-x)Co_(0.5)Er_(x)(0≤x≤0.05)alloys were further prepared by vacuum induction melting and mechanical alloying methods.The saturation magnetization intensity(Ms)increases from 0.141 to 0.182 A·m^(2)/g with increasing Er content.The μ"of Fe_(0.47)Co_(0.5)Er_(0.03)at 16.7 GHz increases from 0.55 to 0.93,and the frequency range over which tanδ_μvalues are greater than 0.5covers 8.0-18.0 GHz,with the maximum value being 0.83 at 17.0 GHz.These results indicate that the Fe_(0.5-x)Co_(0.5)Er_(x)/paraffin composite materials have excellent high-frequency magnetic losses and are promising candidates in the field of microwave-absorbing materials.展开更多
文摘针对小尺度目标在检测时精确率低且易出现漏检和误检等问题,提出一种改进的YOLOv3(You Only Look Once version 3)小目标检测算法。在网络结构方面,为提高基础网络的特征提取能力,使用DenseNet-121密集连接网络替换原Darknet-53网络作为其基础网络,同时修改卷积核尺寸,进一步降低特征图信息的损耗,并且为增强检测模型对小尺度目标的鲁棒性,额外增加第4个尺寸为104×104像素的特征检测层;在对特征图融合操作方面,使用双线性插值法进行上采样操作代替原最近邻插值法上采样操作,解决大部分检测算法中存在的特征严重损失问题;在损失函数方面,使用广义交并比(GIoU)代替交并比(IoU)来计算边界框的损失值,同时引入Focal Loss焦点损失函数作为边界框的置信度损失函数。实验结果表明,改进算法在VisDrone2019数据集上的均值平均精度(mAP)为63.3%,较原始YOLOv3检测模型提高了13.2百分点,并且在GTX 1080 Ti设备上可实现52帧/s的检测速度,对小目标有着较好的检测性能。
文摘Three members of the angiopoietin-like(ANGPTL) protein family-ANGPTL3, ANGPTL4 and ANGPTL8-are important regulators of plasma lipoproteins. They inhibit the enzyme lipoprotein lipase, which plays a key role in the intravascular lipolysis of triglycerides present in some lipoprotein classes. This review focuses on the role of ANGPTL3 as emerged from the study of genetic variants of Angptl3 gene in mice and humans. Both loss of function genetic variants and inactivation of Angptl3 gene in mice are associated with a marked reduction of plasma levels of triglyceride and cholesterol and an increased activity of lipoprotein lipase and endothelial lipase. In humans with ANGPTL3 deficiency, caused by homozygous loss of function(LOF) variants of Angptl3 gene, the levels of all plasma lipoproteins are greatly reduced. This plasma lipid disorder referred to as familial combined hypolipidemia(FHBL2) does not appear to be associated with distinct pathological manifestations. Heterozygous carriers of LOF variants have reduced plasma levels of total cholesterol and triglycerides and are at lower risk of developing atherosclerotic cardiovascular disease, as compared to non-carriers. These observations have paved the way to the development of strategies to reduce the plasma level of atherogenic lipoproteins in man by the inactivation of ANGPTL3, using either a specific monoclonal antibody or anti-sense oligonucleotides.
基金supported by the China National Natural Science Foundation(Grant No.31871597)the Key Research and Development Program of Zhejiang Province,China(Grant No.2021C02063-2)+2 种基金the Key Research and Development Program of China National Rice Research Institute(Grant No.CNRRI-2020-02)the Science and Technology Project of Jiangxi Provincial Department of Education,China(Grant No.GJJ180217)the Project supported by Jiangxi Youth Science Foundation,China(Grant No.20202BAB215001)。
文摘NRL3 is essential for the growth and development of rice leaves.In this study,we found that the loss function of NRL3 also delayed heading date under natural long daylight and short daylight conditions.The yeast two-hybrid and the bimolecular fluorescence complementation proved that NRL3interacts with OsK4,a Snf1-related kinase.OsK4 localized to the nucleus and expressed in various rice tissues.The rhythmic expression pattern of Os K4 was similar to NRL3 under long daylight and short daylight conditions.Knock-out mutants of Os K4 exhibited early heading under long daylight conditions,indicating that it acts as a negative regulator of heading date in rice.Interestingly,the OsK4 mutant under the nrl3 mutant background rescued the late heading phenotype of nrl3 under long daylight conditions,suggesting that Os K4 functions downstream of NRL3.Moreover,both NRL3 and Os K4 controlled heading date through regulating the expression of Hd3a and RFT1 genes.These findings shed light on the heading date regulation in rice and provide a sound theoretical base to improve regional adaptability of rice.
文摘In this work the electronic structure and the impurity excess of the basal and rhombohedral twin grain boundaries are investigated, using electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDXS). The measurability of electronic structures of the twin grain boundaries are discussed by comparing theoretical density of states (DOS) from bulk material with interfacial DOS, obtained from local density functional theory (LDFT) calculations.
基金Project supported by the Nation Natural Science Foundation of China(52304410,51972242)Major Project of Hubei Province(2023BAA003)。
文摘High-frequency magnetic materials are crucial for realizing anti-electromagnetic interference in GHz communication devices and electronic equipment.Current mainstream strategy to enhance highfrequency magnetic losses is shape anisotropy,and it is still difficult to obtain an improvement in intrinsic magnetic loss through electronic structure design.In this paper,the effects of 4f-3d interaction between Er and Fe/Co on magnetic moment,charge migration,and spin polarization were investigated based on density functional theory(DFT).The results show that Er 4f-Fe 3d orbitals undergo significant hybridization at around-4 eV,which increase the electronic locality of Fe and enhance the spin of Fe from 2.86 h/2 to 2.91 h/2.The Fe_(0.5-x)Co_(0.5)Er_(x)(0≤x≤0.05)alloys were further prepared by vacuum induction melting and mechanical alloying methods.The saturation magnetization intensity(Ms)increases from 0.141 to 0.182 A·m^(2)/g with increasing Er content.The μ"of Fe_(0.47)Co_(0.5)Er_(0.03)at 16.7 GHz increases from 0.55 to 0.93,and the frequency range over which tanδ_μvalues are greater than 0.5covers 8.0-18.0 GHz,with the maximum value being 0.83 at 17.0 GHz.These results indicate that the Fe_(0.5-x)Co_(0.5)Er_(x)/paraffin composite materials have excellent high-frequency magnetic losses and are promising candidates in the field of microwave-absorbing materials.
