基于CNN和迁移学习的农作物病害识别方法研究

互联网是一个巨大的资源库,也是一个丰富的知识库。针对农作物小样本引起的过拟合问题,本研究引入了知识迁移和深度学习的方法,采用互联网公开的ImageNet图像大数据集和PlantVillage植物病害公共数据集,以实验室的黄瓜和水稻病害数据集AES-IMAGE为对象开展相关的研究与试验。首先将批归一化算法应用于卷积神经网络CNN中的AlexNet和VGG模型,改善网络的过拟合问题;再利用PlantVillage植物病害数据集得到预训练模型,在改进的网络模型AlexNet和VGG模型上用AES-IMAGE对预训练模型参数调整后进行病害识别。最后,使用瓶颈层特征提取的迁移学习方法,利用ImageNet大数据集训练出的网络参数,将Inception-v3和Mobilenet模型作为特征提取器,进行黄瓜和水稻病害特征提取。本研究结合试验结果探讨了适用于农作物病害识别问题的最佳网络和对应的迁移策略,表明使用VGG网络参数微调的策略可获得的最高准确率为98.33%,使用Mobilenet瓶颈层特征提取的策略可获得96.8%的验证准确率。证明CNN结合迁移学习可以利用充分网络资源来克服大样本难以获取的问题,提高农作物病害识别效率。

Heavy Metal Pollution and Ecological Risk Assessment in Sediments of Xiling Channel Inland Waterway of Guangdong Province

Using the sediment monitoring data of five sections of the Xiling Channel inland waterway of the Pearl River Delta,and using Nemerow composite index,the coefficient of variation,and the index of geoaccumulation( Igeo) and the potential ecological risk index,this paper analyzed and assessed the heavy metal pollution of sediments. The results indicate that Cr reached mild pollution;Cu had a large degree of variation,and the changes of Cr and Zn were significant with fluctuation;the enrichment of heavy metals decreased as follows: Cd > Cu > Cr > Zn> Pb > Ni > Hg > As;Cd had the highest degree of enrichment and belonged to moderate pollution;the ecological hazard of heavy metals was Cd > Hg > Cu > Pb > As > Cr > Ni > Zn,and Cd had the highest ecological hazard and was the main controlling factor of potential ecological risk. In conclusion,the sediments in Xiling Channel inland waterway were polluted by heavy metals to some extent,and cadmium was the main pollutant and had the largest potential ecological risk.

Correlation of genomic and expression alterations of AS3 with esophageal squamous cell carcinoma

Androgen-induced proliferation shutoff gene AS3, also known as APRIN, is a growth inhibitory gene that is initially implicated in prostate cancer. This gene is required for androgen-dependent growth arrest and is a primary target for 1,25（OH）2D3 and androgens. Allelic loss at AS3 locus has been linked to a variety of cancers. However, the correlation of genomic and expression alterations of AS3 with esophageal squamous cell carcinoma （ESCC） is not well established. In this study, the genornic and expression alterations of AS3 in ESCC and their clinical significance are evaluated. Loss of heterozygosity （LOH） analysis using an AS3 intragenic microsatellite marker D13S171 revealed 72% allelic loss at AS3 locus in ESCC, which is significantly correlated with higher pathological grade （P=0.042）. RT-PCR examination showed that AS3 mRNA obviously decreased in 44% tumors and its down-regulation was correlated with the sex of patients （P=0.03）. Furthermore, the correlation between genornic and expression alterations of AS3 gene was analyzed in 18 ESCC specimens, which indicated that the consistency between allelic loss and decreased mRNA expression of AS3 was relatively poor. The results of this study indicate that the aberrant expression of AS3 may be involved in the tumorigenesis of esophagus and is responsible for the male predominance of ESCC.

农产品产地准出与市场准入运行机制探讨

本文阐述了为建立农产品产地准出与市场准入运行机制,农业农村主管部门在农产品法规和政策制定、生产主体建设、开展产地准出与市场准入基础性工作、试行农产品合格证等"四证"制度、构建农产品检测体系等取得的进展基础上,指出了农产品相关法律法规制度建设、生产经营主体准入门槛、农产品生产标准化、农产品准出准入的大市场氛围等方面存在的问题,提出了从法律层面做好农产品准出准入顶层设计、增加农产品产地准出和市场准入机制的内容、制定农产品市场运行技术规范的解决途径。

Using GIS to Analysis Runoff Change in Land Utilization of Foping, Nature Reserve, Shanxi Province

Land use is an indicator of the interaction between human and the environment on the earth surface. Recently, an increasing attention has been paid to the issue of impact of land use and land cover change on environment and water quality. In this paper, we analyzed the land use and land cover change by using RS and GIS, and simulated its implications in runoff from 1991 to 2000 using SCS model in the Foping Nature Reserve, Shan 'xi Province. Our results showed that this region were main plantation, woodland and grassland. Woodland area increased significantly, while plantation and grassland area decreased, which would greatly affect runoff. Meanwhile, the results show that woodland area and land cover area are negatively correlated with the runoff.

Ecological Investigation and Ecological Security Assessment of Xizhijiang River Basin in Huizhou City of Guangdong Province

In addition to such ecological problems as the pollution of the water system,the unreasonable structure of the upstream Basin and the insufficient water conservation forests,the Xizhi River Basin also faces human decision-making problems such as imperfect ecological compensation mechanism.In view of the above problems,using the DPSIR model(Drivers,Pressures,States,Impacts,Responses),this paper analyzed eucalyptus forest in Xizhi River Basin to assess the security of the Xizhi River ecological Basin,and finally concluded that the ecological status of Xizhi River Basin remains safe.

Investigation of Quantum Dot Color Filter Micro-LED Display

In this work,we present the investigation of the quantum dot color filter(QDCF)micro-light emitting diode(micro-LED)display.Green and red quantum dot photoresist(QDPR)materials are patterned into a pixelated array and precisely bonded with an all-blue micro-light emitting diode(micro-LED)substrate,forming a red,green,and blue(RGB)full color display through color conversion.A few factors that influence the achievable color gamut are further investigated.The resulting 1.1-inch 228-pixels per inch(ppi)display demo shows the good performance.The findings in this paper pave a way to the future industrialization of the micro-LED display.

A Broadband Achromatic Dielectric Planar Metalens in Mid-IR Range

Metalens are planar lenses composed of the subwavelengthh arrays,which have unconventional and versatile functionalities to manipulate the light fields compared with the traditional lens.It is noted that the most metalens are designed in a monochromatic mode in the visible or mid-infrared range(mid-IR),however,the broadband range is needed in many practical applications,such as spectroscopy,sensing,and imaging.Here,we design and demonstrate a broadband achromatic dielectric metalens in the mid-IR range of 4μm-5μm for near diffraction-limited(1.0a)focusing.The broadband achromatic propagation and focusing of the metalens are designed and simulated by constructing and optimizing the phase profile.The Pancharatnam-Berry(P-B)phases of all the elements contribute to the main phase increment of the whole phase profile of the metalens.The additional phase is constructed and optimized by using the random search algorithm to obtain the optimized size of all the elements.The focusing efficiency of the achromatic metalens is also optimized and averaged as the result of phase optimization within a wide band for the building elements,while it is lowered comparing with the regular metalens without broadband achromatic designing.Using this combined designing approach,various flat achromatic devices with the broadband metalens can find a new way for full-color detection and imaging.

The Mechanisms of Luteolin in Treating COVID-19 Based on Bioinformatics Analysis and Molecular Docking

Luteolin is a natural flavonoid that has a variety of pharmacological activities, such as anti-inflammatory, anti-allergic, anti-bacterial, anti-viral, apoptosis inhibition, cell autophagy regulation, and anti-tumor activity. It is one of the main ingredients of an expert-recommended herbal formula for the prevention and treatment of coronavirus disease 2019 (COVID-19). This suggests that luteolin has strong pharmacological effects on the prevention and treatment of COVID-19. The aims of this study were to identify the molecular targets of luteolin and to infer the possible mechanisms by which it exerts its pharmacological effects. The GSE159787 data set was obtained from the Gene Expression Omnibus online database, and differentially expressed genes were analyzed. There were 22 upregulated differentially expressed genes enriched in the COVID-19 signaling pathway, suggesting that the upregulation of these genes may be closely related to the occurrence of COVID-19. Molecular docking results showed that luteolin had strong binding efficiency to 20 of these 22 key genes. Six of these genes (CFB, EIF2AK2, OAS1, MAPK11, OAS3, and STAT1) showed strong binding activity. Luteolin can regulate the COVID-19 signaling pathway by combining with these targets, which may have a therapeutic effect on COVID-19.

转炉一次除尘新OG系统高效喷淋塔喷嘴雾化特性的模拟

利用离散相模型对转炉一次除尘新OG系统高效喷淋塔内喷嘴的雾化特性进行模拟,分析了喷射角度、喷射压力、喷射流量及喷嘴水平间距等因素对雾化场索太尔平均直径（SMD）和蒸发效率的影响.结果表明,在一定范围内随喷射角度增加,液滴在雾化场中的覆盖面增大,液滴驻留时间变长,蒸发效率增加,雾化场SMD减小,喷射角度大于60°时,SMD值减小缓慢.随喷射压力增大,液滴蒸发效率增加,雾化场SMD减小,压力大于1.0 MPa时对SMD的影响较小.随喷射流量增加,液滴蒸发效率减小,雾化场SMD增加,流量小于0.15 kg/s时,SMD增加幅度偏小.两喷嘴水平间距越大,液滴分布面积越大,但对雾化场SMD影响较小.在一定条件下,喷嘴间距约为800 mm时,截面速度分布较均匀.

转炉一次除尘新OG系统高效喷淋塔喷嘴布置方式对喷淋特性的影响

采用离散相模型对新OG系统高效喷淋塔入口段及主体段喷嘴的布置方式进行数值模拟,考察了喷嘴喷射方向和喷淋层数对雾化场气流分布和降温效果的影响。结果表明,喷嘴的喷射方向和塔内的喷淋层数对雾化场的气流分布和降温效果影响较大;喷淋塔入口段采用逆流喷射时,出口截面的速度分布最均匀且降温效果最好;高效喷淋塔的主体段的喷淋层数为5时,塔内烟气的速度流场较均匀,且中心区域的气流速度为2~4 m/s,有助于延长气体与液滴的作用时间;随喷淋层数增加,塔内温度梯度变化增大,水蒸气质量分数分布与温度分布对应,塔内的平均湍动能逐渐增高。

沸石咪唑骨架膜的制备及其应用进展

近年来,将金属-有机骨架材料(MOFs)和膜基材料结合,制备新型MOFs分离膜成为膜领域研究的热点之一。由于MOFs具有类似分子筛结构和空间拓扑结构,在分离、催化等方面具有潜在的应用前景。沸石咪唑框架材料(ZIFs)作为MOFs中重要分支之一,因其具有优异的热稳定性和化学稳定性被应用于膜分离。本工作重点阐述了原位生长、界面反扩散、逐层组装、二次生长、气相沉积和微流体处理等方法制备ZIFs多晶膜和杂化膜,并系统介绍了ZIFs复合膜在染料与重金属离子去除、气体分离、天然气净化、生物医药和电化学传感中的应用。最后,总结了ZIFs复合膜制备过程中存在的问题和挑战,并对ZIFs复合膜未来研究的方向提出了展望。要点:(1)介绍了沸石咪唑框架膜的制备方法。(2)综述了沸石咪唑框架膜的应用。(3)分析了沸石咪唑框架材料与膜结合的机理。(4)指出了目前沸石咪唑框架膜的局限性,提出了潜在的发展方向。

Distribution of heavy metals in sediments of the Pearl River Estuary,Southern China:Implications for sources and historical changes

The distribution of heavy metals （Pb, Zn, Cd and As） in sediments of the Pearl River Estuary was investigated. The spatial distribution of heavy metals displayed a decreasing pattern from the turbidity maxima to both upstream and downstream of the estuary, which suggested that suspended sediments played an important role in the trace metal distribution in the Pearl River Estuary. In addition, metal concentrations were higher in the west part of the estuary which received most of the pollutants from the Pearl River. In the sediment cores, fluxes of heavy metals were consistent with a predominant anthropogenic input in the period 1970-1990. From the mid-1990s to the 2000s, there was a significant decline in heavy metal pollution. The observed decline has shown the result of pollution control in the Pearl River Delta. However, it is noteworthy that the metal concentrations in the most recent sediment still remained considerably high. Taken together, the enrichment of heavy metals in sediments was largely controlled by anthropogenic pollution.

Carbon pools and fluxes in the China Seas and adjacent oceans

The China Seas include the South China Sea, East China Sea, Yellow Sea, and Bohai Sea. Located off the Northwestern Pacific margin, covering 4700000 km^2 from tropical to northern temperate zones, and including a variety of continental margins/basins and depths, the China Seas provide typical cases for carbon budget studies. The South China Sea being a deep basin and part of the Western Pacific Warm Pool is characterized by oceanic features; the East China Sea with a wide continental shelf, enormous terrestrial discharges and open margins to the West Pacific, is featured by strong cross-shelf materials transport; the Yellow Sea is featured by the confluence of cold and warm waters; and the Bohai Sea is a shallow semiclosed gulf with strong impacts of human activities. Three large rivers, the Yangtze River, Yellow River, and Pearl River, flow into the East China Sea, the Bohai Sea, and the South China Sea, respectively. The Kuroshio Current at the outer margin of the Chinese continental shelf is one of the two major western boundary currents of the world oceans and its strength and position directly affect the regional climate of China. These characteristics make the China Seas a typical case of marginal seas to study carbon storage and fluxes. This paper systematically analyzes the literature data on the carbon pools and fluxes of the Bohai Sea,Yellow Sea, East China Sea, and South China Sea, including different interfaces(land-sea, sea-air, sediment-water, and marginal sea-open ocean) and different ecosystems(mangroves, wetland, seagrass beds, macroalgae mariculture, coral reefs, euphotic zones, and water column). Among the four seas, the Bohai Sea and South China Sea are acting as CO_2 sources, releasing about0.22 and 13.86–33.60 Tg C yr^(-1) into the atmosphere, respectively, whereas the Yellow Sea and East China Sea are acting as carbon sinks, absorbing about 1.15 and 6.92–23.30 Tg C yr^(-1) of atmospheric CO_2, respectively. Overall, if only the CO_2 exchange at the sea-air interface is considered, the Chinese marginal seas appear to be a source of atmospheric CO_2, with a net release of 6.01–9.33 Tg C yr^(-1), mainly from the inputs of rivers and adjacent oceans. The riverine dissolved inorganic carbon (DIC) input into the Bohai Sea and Yellow Sea, East China Sea, and South China Sea are 5.04, 14.60, and 40.14 Tg C yr^(-1),respectively. The DIC input from adjacent oceans is as high as 144.81 Tg C yr^(-1), significantly exceeding the carbon released from the seas to the atmosphere. In terms of output, the depositional fluxes of organic carbon in the Bohai Sea, Yellow Sea, East China Sea, and South China Sea are 2.00, 3.60, 7.40, and 5.92 Tg C yr^(-1), respectively. The fluxes of organic carbon from the East China Sea and South China Sea to the adjacent oceans are 15.25–36.70 and 43.93 Tg C yr^(-1), respectively. The annual carbon storage of mangroves, wetlands, and seagrass in Chinese coastal waters is 0.36–1.75 Tg C yr^(-1), with a dissolved organic carbon(DOC) output from seagrass beds of up to 0.59 Tg C yr^(-1). Removable organic carbon flux by Chinese macroalgae mariculture account for 0.68 Tg C yr^(-1) and the associated POC depositional and DOC releasing fluxes are 0.14 and 0.82 Tg C yr^(-1), respectively. Thus, in total, the annual output of organic carbon, which is mainly DOC, in the China Seas is 81.72–104.56 Tg C yr^(-1). The DOC efflux from the East China Sea to the adjacent oceans is 15.00–35.00 Tg C yr^(-1). The DOC efflux from the South China Sea is 31.39 Tg C yr^(-1). Although the marginal China Seas seem to be a source of atmospheric CO_2 based on the CO_2 flux at the sea-air interface, the combined effects of the riverine input in the area, oceanic input, depositional export,and microbial carbon pump(DOC conversion and output) indicate that the China Seas represent an important carbon storage area.

Cross-cultural adaption and psychometric properties of the Chinese version of the Diabetes Behavior Rating Scale: a pilot study

Self-care behavior plays a major role in diabetic management. However, in China, a satisfactory instrument has not yet been developed to evaluate the compliance of self-care behavior for young patients with type 1 diabetes mellitus(T1 DM). The Diabetes Behavior Rating Scale(DBRS) has a potential to be the first mature instrument. The purpose of this study is to cross-culturally adapt the DBRS, and preliminarily evaluate its psychometric properties. The instrument translation included translation, back translation and culture adaptation. Psychometric properties were assessed in a sample of 116 young patients with T1 DM adapting insulin injection therapy. The Chinese version of the DBRS was divided to four subscales. Cronbach's α for the total scale was 0.92. The mean inter-item and item-total correlations were 0.35 and 0.54 respectively. Test-retest reliability showed good temporal stability(r=0.81, P=0.001). Negative correlations were found between DBRS scores with the Diabetes Distress Scale scores(r=.0.32, P=0.003) and hemoglobin A1 c(HbA1 c) levels(r=.0.36, P=0.002). Higher DBRS scores correlated with better glycemic control. The Chinese insulin injection therapy version of the DBRS is well translated and culturally adapted. It shows good overall reliability and validity and appears to be a valuable tool for assessing the diabetic self-care behaviors for young patients with T1 DM.

Spatial and Seasonal Variations of Nutrients in Sediment Profiles and Their Sediment-Water Fluxes in the Pearl River Estuary,Southern China

Three cruises were launched in the Pearl River Estuary （PRE） in 2005 to investigate the biogeochemical cycling of nutrients associated with early diagenesis related to degradation of organic matter. Seasonal and spatial variations of pore water nutrient concentrations and profile patterns in sediments were studied. Nutrient fluxes at the sediment-water interface （SWI） were measured by incu- bation experiments, and we here discussed the accumulation and transformation processes of nutrients at the SWI. The nutrients generally decreased from the Pearl River outlets downstream, indicating an- thropogenic influences on the nutrient inputs in the estuary. NO3-N concentration was the highest of the three forms of DIN （dissolved inorganic nitrogen, the sum of NH4-N, NO3-N and NO2-N） in the overly- ing water, and NH4-N was the main component of DIN in pore water. The gradual increase of NH4-N and the rapid decrease of NO3-N with sediment depth provided the evidence for anaerobic conditions below the SWI. Negative fluxes of NO3-N and positive fluxes of NH4-N were commonly observed, sug- gesting the denitrification of NO3-N at the SWL The DIN flux direction suggested that the sediment was the sink of DIN in spring, however, the sediment was generally the source of DIN in summer and winter. PO4-P distribution patterns were distinct while SiO4-Si inconspicuously varied in sediment profiles in different seasons. The flux results indicated that PO4-P mainly diffused from the water column to the sediment while SiO4-Si mainly diffused from the sediment to the water column. Generally, the incu- bated fluxes were the coupling of diffusion, bioturbation and biochemical reactions, and were relatively accurate in this study.

Rabies Virus Pseudotyped with CVS-N2C Glycoprotein as a Powerful Tool for Retrograde Neuronal Network Tracing

Efficient viral vectors for mapping and manipulating long-projection neuronal circuits are crucial in structural and functional studies of the brain. The SAD strain rabies virus with the glycoprotein gene deleted pseudotyped with the N2 C glycoprotein(SAD-RV(DG)-N2 C(G)) shows strong neuro-tropism in cell culture, but its in vivo efficiency for retrograde gene transduction and neuro-tropism have not been systematically characterized.We compared these features in different mouse brain regions for SAD-RV-N2 C(G) and two other widely-used retrograde tracers, SAD-RV(DG)-B19(G) and r AAV2-retro. We found that SAD-RV(DG)-N2 C(G) enhanced the infection efficiency of long-projecting neurons by^10 times but with very similar neuro-tropism, compared with SAD-RV(DG)-B19(G). On the other hand, SAD-RV(DG)-N2 C(G) had an infection efficiency comparable with r AAV2-retro, but a more restricted diffusion range, and broader tropism to different types and regions of longprojecting neuronal populations. These results demonstrate that SAD-RV(DG)-N2 C(G) can serve as an effective retrograde vector for studying neuronal circuits.

Relationship between nutrients and plankton biomass in the turbidity maximum zone of the Pearl River Estuary

Nutrients,dissolved and particulate organic carbon and plankton（bacterio-,phyto-and zoo-）were compared in the turbidity maximum zone（TMZ） and adjacent areas（non-TMZ） in the Pearl River estuary.Our results showed that high levels of suspended substances had marked effect on dynamics of nutrients and plankton in the TMZ.Based on the cluster analysis of total suspended solids（TSS） concentrations,all stations were divided into two groups,TMZ with average TSS of 171 mg/L and non-TMZ of 45 mg/L.Suspended substances adsorbed PO^（3-）_4 and dissolved organic carbon,resulting in higher particulate phosphorus and organic carbon（POC）and lower PO^（3-）_4 and DOC in the TMZ,compared to the non-TMZ.However,suspended substances had limited effect on nitrogenous nutrients.Phytoplankton growth was light-limited due to high concentrations of suspended substances in the TMZ and a peak of phytoplankton abundance appeared in the non-TMZ.In contrast,the highest bacterial abundance occurred in the TMZ,which was likely partly responsible for low DOC levels.Two peaks of zooplankton abundance observed in the TMZ and non-TMZ in the Pearl River estuary were primarily supported by bacteria and phytoplankton,respectively.Our finding implied that high levels of suspended solids in the TMZ affect the trophic balance.

Picoplankton and virioplankton abundance and community structure in Pearl River Estuary and Daya Bay, South China

By using flow cytometry techniques, we investigated the abundance and composition of the heterotrophic prokaryotes, virioplankton and picophytoplankton community in the Pearl River Estuary and Daya Bay in the summer of 2012. We identified two subgroups of prokaryotes, high nucleic acid（HNA） and low nucleic acid（LNA）, characterized by different nucleic acid contents. HNA abundance was significantly correlated with larger phytoplankton and Synechococcus（Syn） abundance, which suggested the important role of organic substrates released from primary producers on bacterial growth. Although LNA did not show any association with environmental variables, it was a vital component of the microbial community. In contrast to previous studies, the total virioplankton concentration had a poor relationship with nutrient availability. The positive relationship between large-sized phytoplankton abundance and the V-I population confirmed that V-I was a phytoplankton-infecting viral subgroup. Although the V-II group（bacteriophages）was dominant in the virioplankton community, it was not related with prokaryotic abundance, which indicated factors other than hosts controlling V-II abundance or the uncertainty of virus-host coupling. With respect to the picophytoplankton community,our results implied that river input exerted a strong limitation to Syn distribution in the estuary, while picoeukaryotes（Euk） were numerically less abundant and showed a quite different distribution pattern from that of Syn, and hence presented ecological properties distinct from Syn in our two studied areas.

Optical analysis method for fast plasma characterization of high-speed miniaturized synthetic jet

In this paper,a new optical analysis method for plasma characterization is proposed.Plasma characteristics are obtained directly by measuring the plasma luminous color,rather than the complex spectral diagnosis method,which is difficult to obtain at high speed.By using the light transmittance curve of the human cornea,the RGB coordinates are calculated from the measured plasma spectrum data.Plasma characteristics are diagnosed using the Boltzmann plot method and the Stark broadening method.The corresponding relationship of the electron temperature,electron density data points,and luminous color is established and analyzed.Our research results indicate that this optical analysis method is feasible and promising for fast plasma characterization.