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Low-profile,low sidelobe array antenna with ultrawide beam coverage for UAV communication 被引量:1
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作者 Mei LI Zhiliang SHANG +2 位作者 Lin PU Ming-Chun TANG Lei ZHU 《Chinese Journal of Aeronautics》 2025年第1期444-454,共11页
This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage,low profile,and low Sidelobe Level(SLL)for the application of Unmanned Aerial Vehicle(UAV)air-to-ground commu... This paper presents a design method to implement an antenna array characterized by ultra-wide beam coverage,low profile,and low Sidelobe Level(SLL)for the application of Unmanned Aerial Vehicle(UAV)air-to-ground communication.The array consists of ten broadside-radiating,ultrawide-beamwidth elements that are cascaded by a central-symmetry series-fed network with tapered currents following Dolph-Chebyshev distribution to provide low SLL.First,an innovative design of end-fire Huygens source antenna that is compatible with metal ground is presented.A low-profile,half-mode Microstrip Patch Antenna(MPA)is utilized to serve as the magnetic dipole and a monopole is utilized to serves as the electric dipole,constructing the compact,end-fire,grounded Huygens source antenna.Then,two opposite-oriented end-fire Huygens source antennas are seamlessly integrated into a single antenna element in the form of monopole-loaded MPA to accomplish the ultrawide,broadside-radiating beam.Particular consideration has been applied into the design of series-fed network as well as antenna element to compensate the adverse coupling effects between elements on the radiation performance.Experiment indicates an ultrawide Half-Power Beamwidth(HPBW)of 161°and a low SLL of-25 dB with a high gain of 12 d Bi under a single-layer configuration.The concurrent ultrawide beamwidth and low SLL make it particularly attractive for applications of UAV air-to-ground communication. 展开更多
关键词 Array antenna Broad beam Fan beam Low sidelobe level Chebyshev synthesis UAV communication
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An Ensembled Multi-Layer Automatic-Constructed Weighted Online Broad Learning System for Fault Detection in Cellular Networks
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作者 Wang Qi Pan Zhiwen +1 位作者 Liu Nan You Xiaohu 《China Communications》 2025年第8期150-167,共18页
6G is desired to support more intelligence networks and this trend attaches importance to the self-healing capability if degradation emerges in the cellular networks.As a primary component of selfhealing networks,faul... 6G is desired to support more intelligence networks and this trend attaches importance to the self-healing capability if degradation emerges in the cellular networks.As a primary component of selfhealing networks,fault detection is investigated in this paper.Considering the fast response and low timeand-computational consumption,it is the first time that the Online Broad Learning System(OBLS)is applied to identify outages in cellular networks.In addition,the Automatic-constructed Online Broad Learning System(AOBLS)is put forward to rationalize its structure and consequently avoid over-fitting and under-fitting.Furthermore,a multi-layer classification structure is proposed to further improve the classification performance.To face the challenges caused by imbalanced data in fault detection problems,a novel weighting strategy is derived to achieve the Multilayer Automatic-constructed Weighted Online Broad Learning System(MAWOBLS)and ensemble learning with retrained Support Vector Machine(SVM),denoted as EMAWOBLS,for superior treatment with this imbalance issue.Simulation results show that the proposed algorithm has excellent performance in detecting faults with satisfactory time usage. 展开更多
关键词 broad learning system(BLS) cell outage detection cellular network fault detection ensemble learning imbalanced classification online broad learning system(OBLS) self-healing network weighted broad learning system(WBLS)
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Diagnostic and surgical management of giant broad ligament myoma with cystic degeneration:A case report
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作者 Xue Huang Qiang Yao +1 位作者 Yi-Cheng Wu Shi-Cong Liu 《World Journal of Clinical Cases》 2025年第27期105-113,共9页
BACKGROUND Leiomyomas or fibroids commonly originate from the uterus;extrauterine leiomyomas are rare and most often arise from the broad ligament.Diagnosing broad ligament leiomyomas becomes particularly challenging ... BACKGROUND Leiomyomas or fibroids commonly originate from the uterus;extrauterine leiomyomas are rare and most often arise from the broad ligament.Diagnosing broad ligament leiomyomas becomes particularly challenging when they undergo degenerative changes because their clinical and radiological features often mimic those of ovarian tumors.We report a rare case of a giant broad ligament fibroid with cystic degeneration,which was initially mistaken for an ovarian mass.CASE SUMMARY A 49-year-old woman presented with mild abdominal distension and pain as the only symptoms.Upon abdominal examination,a large mass measuring approximately 30 cm and extending from the pelvic cavity to just below the xiphoid process was identified.Both transvaginal ultrasound and contrast-enhanced computed tomography suggested an ovarian origin of the mass.However,laparotomy confirmed that the mass originated from the right broad ligament.The mass was separated from the uterus and bilateral ovaries,with no involvement of the uterus or ovaries.The mass was completely resected with respecting the patient’s desire to retain her uterus and adnexa.Postoperative histopathological examination confirmed leiomyoma with cystic degeneration.CONCLUSION Broad ligament myomas mimic ovarian tumors;accurate diagnosis and careful operation are critical to avoid complications and ensure safety. 展开更多
关键词 Broad ligament myoma Giant leiomyoma Cystic degeneration Ovarian tumor Surgical management Case report
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Identification of a genomic region controlling broad-spectrum immunity to leaf rust in wheat–Agropyron cristatum 2P translocation lines
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作者 Xiajie Ji Shirui Xu +10 位作者 Zongyao Wang Haiming Han Jinpeng Zhang Shenghui Zhou Baojin Guo Xinming Yang Xiuquan Li Xiaomin Guo Taiguo Liu Lihui Li Weihua Liu 《Journal of Integrative Agriculture》 2025年第5期2015-2018,共4页
Wheat leaf rust,caused by Puccinia triticina(Pt),is one of the most devastating diseases in common wheat(Triticum aestivum L.)and can lead to heavy yield loss(Chai et al.2020).Leaf rust can result in 50%yield loss dur... Wheat leaf rust,caused by Puccinia triticina(Pt),is one of the most devastating diseases in common wheat(Triticum aestivum L.)and can lead to heavy yield loss(Chai et al.2020).Leaf rust can result in 50%yield loss during epidemic years(Huerta-Espino et al.2011;Gebrewahid et al.2020;Kolomiets et al.2021).Breeding varieties resistant to leaf rust have been recognized as the most effective and economical method to mitigate wheat losses caused by Pt.The narrow genetic basis of wheat constrains the number of cultivars resistant to leaf rust(Jin et al.2021). 展开更多
关键词 broad spectrum immunity leaf rustcaused Agropyron cristatum genomic region p translocation lines puccinia triticina pt leaf rust WHEAT
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CAFIU Vice-President Liu Hongcai Met with Seiji Yamamoto
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《International Understanding》 2025年第1期12-12,共1页
On 18 December 2024,Liu Hongcai,Vice-President of CAFIU met with Seiji Yamamoto,Director General of the Broad National Alliance for Independence,Peace and Democracy of Japan.The two sides exchanged views on China-Japa... On 18 December 2024,Liu Hongcai,Vice-President of CAFIU met with Seiji Yamamoto,Director General of the Broad National Alliance for Independence,Peace and Democracy of Japan.The two sides exchanged views on China-Japan relations,people-to-people exchanges and cooperation between the two organisations. 展开更多
关键词 Seiji Yamamoto Peace Democracy Japan People People Exchanges Cooperation Broad National Alliance Independence Liu Hongcai CAFIU China Japan Relations
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Electromagnetic collaborative optimization of DyFe-MOFs derivatives for ultra-thin electromagnetic wave absorption
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作者 Xiaoli Wang Juhua Luo +4 位作者 Shuangshuang Mao Daqing Cheng Xing Liu Yu Xie Lichun Cheng 《Journal of Advanced Ceramics》 2025年第12期65-76,共12页
Achieving high-performance electromagnetic wave absorption(EMWA)capacity at thinner thicknesses remains a critical yet challenging objective.In this study,Dy_(2)O_(3)/Fe_(3)C/N-doped carbon(DFC)composites were synthes... Achieving high-performance electromagnetic wave absorption(EMWA)capacity at thinner thicknesses remains a critical yet challenging objective.In this study,Dy_(2)O_(3)/Fe_(3)C/N-doped carbon(DFC)composites were synthesized via a solvothermal process followed by high-temperature carbonization,with metal-organic frameworks(MOFs)used as precursors.By systematically adjusting the molar ratio of Dy^(3+)/Fe^(3+),the dielectric and magnetic properties of the materials were synergistically optimized.The EMWA performance exhibited a nonmonotonic dependence on the Dy^(3+)content,first increasing before decreasing at higher concentrations.At an optimal Dy^(3+)/Fe^(3+)molar ratio of 1.2:0.8,the DFC composites demonstrated a remarkable minimum reflection loss value of-56.08 dB at a mere 1.76 mm thickness,alongside an effective absorption bandwidth value of 5.12 GHz(12.56–17.68 GHz).The exceptional EMWA performance stems from optimized impedance matching,multiple scattering and reflections,dielectric loss,and magnetic loss.Furthermore,radar cross-section simulations validated the material’s practical applicability.Therefore,this work provides a novel strategy for designing next-generation EMWA materials with ultra-thin profiles and wideband absorption capabilities. 展开更多
关键词 electromagnetic wave absorption(EMWA) metal-organic frameworks(MOFs) impedance matching broad bandwidth
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Broad-Learning-System-Based Model-Free Adaptive Predictive Control for Nonlinear MASs Under DoS Attacks
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作者 Hongxing Xiong Guangdeng Chen +1 位作者 Hongru Ren Hongyi Li 《IEEE/CAA Journal of Automatica Sinica》 2025年第2期381-393,共13页
In this paper, the containment control problem in nonlinear multi-agent systems(NMASs) under denial-of-service(DoS) attacks is addressed. Firstly, a prediction model is obtained using the broad learning technique to t... In this paper, the containment control problem in nonlinear multi-agent systems(NMASs) under denial-of-service(DoS) attacks is addressed. Firstly, a prediction model is obtained using the broad learning technique to train historical data generated by the system offline without DoS attacks. Secondly, the dynamic linearization method is used to obtain the equivalent linearization model of NMASs. Then, a novel model-free adaptive predictive control(MFAPC) framework based on historical and online data generated by the system is proposed, which combines the trained prediction model with the model-free adaptive control method. The development of the MFAPC method motivates a much simpler robust predictive control solution that is convenient to use in the case of DoS attacks. Meanwhile, the MFAPC algorithm provides a unified predictive framework for solving consensus tracking and containment control problems. The boundedness of the containment error can be proven by using the contraction mapping principle and the mathematical induction method. Finally, the proposed MFAPC is assessed through comparative experiments. 展开更多
关键词 Broad learning technique denial-of-service(DoS) model-free adaptive predictive control(MFAPC) nonlinear multiagent systems(NMASs)
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Photoelectric properties of the semiconductor Bi_(2)YbO_(4)Cl with broad spectral response
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作者 Qibing Li Hong Li +2 位作者 Kai Zhang Tianwu Wang Guangyou Fang 《Journal of Rare Earths》 2025年第9期1852-1858,共7页
Bi_(2)YbO_(4)Cl with a fluorite layer structure belongs to the family of the bismuth rare-earth oxyhalides Bi_(2)REO_(4)X(X=Cl,B r,I).However,the synthesis and photoelectric properties of Bi_(2)YbO_(4)Cl have almost n... Bi_(2)YbO_(4)Cl with a fluorite layer structure belongs to the family of the bismuth rare-earth oxyhalides Bi_(2)REO_(4)X(X=Cl,B r,I).However,the synthesis and photoelectric properties of Bi_(2)YbO_(4)Cl have almost not been reported.In this work,Bi_(2)YbO_(4)Cl was synthesized using the solid-state method and the solvothermal method.Yb3+ions show a strong characteristic absorption peak at 980 nm,which was measured by ultraviolet-visible-near-infrared absorption spectra.The transient photoconductivity of Bi_(2)YbO_(4)Cl was obtained by time-resolved terahertz spectroscopy system under 400 and 800 nm laser excitations,respectively.The frequency-dependent transient photoconductivity analysis reveals the Drude-Smith behavior in Bi_(2)YbO_(4)Cl.Under photoexcitation,the hot charge carriers with a long relaxation lifetime and a carrier mobility of 48 cm^(2)/(V·s) are obtained.The synthesis of Bi_(2)YbO_(4)Cl is of great significance for the development of novel photocatalytic and photo harvesting materials with broad spectral response. 展开更多
关键词 Bi_(2)YbO_(4)Cl Broad spectral response Transient photoconductivity Carrier mobility Rare earths
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Rewiring autoactive NLRs into protease-activated switches for broad-spectrum plant immunity
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作者 Yuting Zhang Muhammad Naveed Aslam Yule Liu 《The Crop Journal》 2025年第6期1660-1662,共3页
Remodeling plant intracellular nucleotide-binding leucine-rich repeat immune receptors(NLRs)to engineer synthetic disease-resistance genes has emerged as a promising approach to achieving broad-spectrum disease resist... Remodeling plant intracellular nucleotide-binding leucine-rich repeat immune receptors(NLRs)to engineer synthetic disease-resistance genes has emerged as a promising approach to achieving broad-spectrum disease resistance.But strategies for expanding NLR recognition spectra[[1],[2],[3],[4],[5]]are often limited by the rapid evolution of pathogens and pests.In our recent study,we developed an innovative strategy to engineer broad-spectrum,durable and complete disease resistance in plants by remodeling autoactive NLRs into protease-activated switches[6]. 展开更多
关键词 disease resistance synthetic disease resistance genes autoactive NLRS remodeling autoacti plant immunity protease activated switches nucleotide binding leucine rich repeat immune receptors broad spectrum disease resistance
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AL5E:A breakthrough in broad-spectrum coronavirus inactivation through structure-guided design
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作者 Heng Gao Jiwei Zhang +1 位作者 Peng Zhan Xinyong Liu 《Chinese Chemical Letters》 2025年第7期1-3,共3页
Coronaviruses are single-stranded,positive-sense RNA enveloped viruses that have posed a significant threat to human health over the past few decades,particularly severe acute respiratory syndrome coronavirus(SARS-CoV... Coronaviruses are single-stranded,positive-sense RNA enveloped viruses that have posed a significant threat to human health over the past few decades,particularly severe acute respiratory syndrome coronavirus(SARS-CoV),Middle East respiratory syndrome coronavirus(MERS-CoV),and SARS-CoV-2.These viruses have caused widespread infections and fatalities,with profound impacts on global economies,social life,and public health systems.Due to their broad host range in natural settings and the consequent high potential for zoonotic spillover events,a thorough investigation of the common viral mechanisms and the identification of druggable targets for pan-coronavirus antiviral development are of utmost importance. 展开更多
关键词 severe acute respiratory syndrome coronavirus single stranded positive sense RNA middle east respiratory syndrome coronavirus SARS CoV CORONAVIRUS structure guided design severe acute respiratory syndrome coronavirus sars cov middle broad spectrum inactivation
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Nutritional Value and Application of Broad Bean Nutrition Flour as a Combination of Staple Food 被引量:4
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作者 吴春芳 林晶晶 +2 位作者 卞晓春 陈惠 夏礼如 《Agricultural Science & Technology》 CAS 2015年第6期1280-1285,共6页
This paper introduced the definition and importance of combination of sta-ple food. With broad bean nutrition flour as a sample, the preparation of the combi-nation of staple food was also described. In addition, the ... This paper introduced the definition and importance of combination of sta-ple food. With broad bean nutrition flour as a sample, the preparation of the combi-nation of staple food was also described. In addition, the main nutritional value of broad bean nutrition flour was introduced. Compared with those of other single flours, the nutritional value of broad bean nutrition flour was improved. Moreover, the nutrients in the broad bean nutrition flour would not be destroyed during the processing and preparation of staple food, and the processed steamed bread and raw noodle are more characteristic. The application value and prospects of broad bean nutrition flour, as a combination of staple food, were further discussed. 展开更多
关键词 Broad bean nutrition flour Combination of staple food APPLICATION
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FTIR Spectroscopic Study of Broad Bean Diseased Leaves 被引量:2
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作者 李志永 刘刚 +5 位作者 李伦 欧全宏 赵兴祥 张黎 周湘萍 汪禄祥 《Agricultural Science & Technology》 CAS 2012年第11期2363-2366,2408,共5页
[Objective] The aim was to indentify diseased leaves of broad bean by vibra- tional spectroscopy. [Method] In this paper, broad bean rust, fusarium rhizome rot, broad bean zonate spot, yellow leaf curl virus and norma... [Objective] The aim was to indentify diseased leaves of broad bean by vibra- tional spectroscopy. [Method] In this paper, broad bean rust, fusarium rhizome rot, broad bean zonate spot, yellow leaf curl virus and normal leaves were studied using Fourier transform infrared spectroscopy combined with chemometrics. [Result] The spectra of the samples were similar, only with minor differences in absorption inten- sity of several peaks. Second derivative analyses show that the significant difference of all samples was in the range of 1 200-700 cm2. The data in the range of 1 200- 700 cm' were selected to evaluate correlation coefficients, hierarchical cluster analy- sis (HCA) and principal component analysis (PCA). Results showed that the correla- tion coefficients are larger than 0.928 not only between the healthy leaves, but also between the same diseased leaves. The values between healthy and diseased leaves, and among diseased leaves, are all declined. HCA and PCA yielded about 73.3% and 82.2% accuracy, respectively. [Conclusion] This study demonstrated that FTIR techniques might be used to detect crop diseases. 展开更多
关键词 FTIR spectroscopy Broad bean diseases Principal component analysis Cluster analysis
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Effects of Facilities Condition on Occurrence of Freeze Injury and Fresh Pod Yield of Broad Bean 被引量:2
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作者 吴春芳 卞晓春 +1 位作者 曹云英 夏礼如 《Agricultural Science & Technology》 CAS 2015年第5期890-897,共8页
Using Tongxian No.2 as material, the effects of different film-covering time, different sowing time and different planting density on the occurrence of freeze injury and yield of fresh broad beans were investigated. T... Using Tongxian No.2 as material, the effects of different film-covering time, different sowing time and different planting density on the occurrence of freeze injury and yield of fresh broad beans were investigated. The randomized block design was adopted. The results showed that with the delayed film covering, the incidence of mild freeze injury and number of headless seedlings were increased correspondingly, but the yield was increased; with the delayed sowing, the branch number per plant, effective branch number per plant, incidence of mild freeze injury and number of headless seedlings were all reduced, and the broad beans, sowed on September 30 th, obtained the highest yield; planting density showed on effect on the occurrence of freeze injury, and the yield was increased with the increase of planting density. Under the same film-covering time, the incidence of freeze injury was reduced with the delayed sowing time and it showed no changes when planting density was changed, but the yield was increased with the increase of planting density and it was highest when broad bean seeds were sowed on September 30th;under the same sowing time, the incidence of freeze injury was increased with the delayed film-covering time and it showed no changes when planting density was changed, and the yield was increased with the delayed film-covering time and increased planting density; under the same planting density, the incidence of freeze injury was increased with the delayed film-covering time but was reduced with the delayed sowing time, and the yield was increased with the delayed film-covering time and it was highest when the broad bean seeds were sowed on September30 th. Under same film-covering time and sowing time, the total branch number per plant and effective branch number per plant were reduced, but the yield was increased with the increase of planting density; under same film-covering time and planting density, the incidence of freeze injury was reduced with the delayed sowing time, and the yield was highest when broad bean seeds were sowed on September30th; under same sowing time and planting density, the incidence of freeze injury and the yield were all increased with the delayed film-covering time. 展开更多
关键词 Facility broad bean Film-covering time Sowing time Planting density Freeze injury Fresh pod yield
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蚕豆染色病毒CPS基因的序列测定及RT-PCR检测方法的建立 被引量:1
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作者 陈红运 陈青 +4 位作者 黄峰 赵文军 廖富荣 陈洪俊 朱水芳 《植物病理学报》 CAS CSCD 北大核心 2009年第6期646-649,共4页
The nucleotide sequence of small coat protein(CPS) gene of Broad bean stain virus(BBSV) was determined and compared with other comoviruses.The CPS gene of BBSV consisted of 687 nucleotides and encodes a putative prote... The nucleotide sequence of small coat protein(CPS) gene of Broad bean stain virus(BBSV) was determined and compared with other comoviruses.The CPS gene of BBSV consisted of 687 nucleotides and encodes a putative protein of 228 amino acid residues.The CPS sequence of BBSV and those of other comoviruses shared identities of 36.5%-58.9% and 35.2%-70.3% at the nucleotide and amino acid levels,respectively.The RT-PCR method specific for BBSV detection was developed based on the determined CPS sequence.The RT-PCR assay presented here allows,for the first time,rapid and specific detection of BBSV. 展开更多
关键词 Broad bean stain virus small coat protein detection
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Detection of Broad Bean Diseases by Fourier Transform Infrared Spectroscopy Combined with Curve Fitting 被引量:1
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作者 汪小华 刘刚 +4 位作者 欧全宏 周湘萍 郝建明 刘剑虹 汪禄祥 《Agricultural Science & Technology》 CAS 2015年第6期1310-1313,共4页
Fourier transform infrared (FTIR) spectroscopy was used to study diseased leaves in broad bean. Results showed that the infrared spectra of different broad bean diseased leaves were similar, which were mainly made u... Fourier transform infrared (FTIR) spectroscopy was used to study diseased leaves in broad bean. Results showed that the infrared spectra of different broad bean diseased leaves were similar, which were mainly made up of the vibrational absorption bands of protein,lipid and polysaccharide.There were minor differences in-cluding the spectral peak position, peak shape and the absorption intensity in the range of 1 800-1 300 cm-1. There were obvious differences among their second derivative spectra in the range of 1 800-1 300 cm-1. After the procedure of the Fourier self-deconvolution and curve fitting of health bean leaves and broad bean diseased leaves in the range of 1 700-1 500 cm-1, three sub-peaks were obtained at 1 550 cm-1 (protein amide Ⅱ band), 1 605 cm-1 (lignin) and 1 650 cm-1 (protein amide I band).The ratios of relative areas of the bands of amide Ⅱ, lignin, and amide I were 38.86%, 28.68% and 32.47% in the spectra of healthy leaves, respec-tively. It was distinguished from the diseased leaves (chocolate spot leaf: 15.42%, 42.98% and 41.61%, ring spot leaf:32.39%, 35.63% and 31.98%, rust leaf: 13.97%, 46.40% and 39.65%, yel owing leaf curl disease leaf: 24.01%,36.55% and 39.44%). For sub-peak area ratios (A1 563/A1 605, A1 650/A1 605 and A1 563/A1 654), those of four kinds of diseased leaves were smal er than that of healthy leaves, and there were also differences among four kinds of diseased leaves. The results proved that FTIR combining with curve fitting might be a potential y useful tool for detecting different kinds of broad bean diseases. 展开更多
关键词 Fourier transform infrared (FTIR) spectroscopy Broad bean diseases Second derivative spectra Curve fitting
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高精度感光制板研究与实践 被引量:1
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作者 陈玮 顾思思 《邵阳学院学报(自然科学版)》 2008年第1期33-36,共4页
PWB(Printed Wre Broad)是电子产品不可或缺的重要组件,PWB感光制作具有制作方便、出板快、成本低等优点.本文基于近百次PWB感光制作,研究分析了感光制板各阶段操作要领,提出了确保PWB制作精度和成功率的改进措施.实践表明:本文强调的... PWB(Printed Wre Broad)是电子产品不可或缺的重要组件,PWB感光制作具有制作方便、出板快、成本低等优点.本文基于近百次PWB感光制作,研究分析了感光制板各阶段操作要领,提出了确保PWB制作精度和成功率的改进措施.实践表明:本文强调的操作要领是决定制作成功与否的关键,提出的改进措施可以提高制板精度,最小线宽、间距可达4.7mil,接近PCB专业厂家的工艺能力。 展开更多
关键词 PWB(Printed WIRE Broad) 感光制作 精度 成功率
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Effects of Pb on Growth and Development of Broad Bean Roots
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作者 张燕 《Agricultural Science & Technology》 CAS 2013年第4期595-597,共3页
[Objective] This study aimed to investigate the influence of Pb2+ on the growth and development of broad bean roots. [Method] The effects of Pb2+ solution of different concentrations on root length, color, bending a... [Objective] This study aimed to investigate the influence of Pb2+ on the growth and development of broad bean roots. [Method] The effects of Pb2+ solution of different concentrations on root length, color, bending and mitotic index frequency of root tip cells of broad bean were measured and observed. [Result] Pb2+ at concentration lower than 20 mg/L promoted the growth and development of roots, increased the cell mitotic indexes, but had little influence on root color and bending. When the Pb2+ concentration was higher than 20 mg/L, the root growth was inhibited; the root color gradually turned deeper; the roots bended, but the cell mitotic index was decreased. [Conclusion] Pb2+ promoted the growth of broad bean at low concentration but inhibited the growth at high concentration, and the influence was related to Pb2+ concentration and time. 展开更多
关键词 Pb2+ Broad bean Root length BENDING COLOR MITOSIS
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长期生态学研究中的经典实验途径——Lawcs和Gilbrt的Broad balk实验
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作者 周德本 《国土与自然资源研究》 1992年第S1期19-21,共3页
没有长期实验领域的资料而去讨论长期实验是困难的,最早的实验在Rothamsted进行,在那里,测定了植物的氮素来源和化肥及农家肥对小麦产量的影响,该实验始于1843年,与类似的芜%Barnfild实验一样,随后变得更复杂而最终终止了。Barnfield... 没有长期实验领域的资料而去讨论长期实验是困难的,最早的实验在Rothamsted进行,在那里,测定了植物的氮素来源和化肥及农家肥对小麦产量的影响,该实验始于1843年,与类似的芜%Barnfild实验一样,随后变得更复杂而最终终止了。Barnfield实验以其简单的形式,仍然存在着而基本上没有改变,就象那时能够想象一样,该实验对“长期实验”做出了贡献,简单的设计可能是其成功的关键。当随后R.A.Fi sher试图分析时,这导致他设计新的野外实验统计和随机因子设计(Fisher 1925,1935),并变成了后来田间分析的基础;因为Broadbalk没有反复的实验,现在也不能重复;已经产生了如此多的不同且可改变的变化,就象后来土壤分析所示的,这是在做到最初目的之后继续取样的。存在(Survival)已是实验最显著的成就之一,一起进行的有费歇尔(Fi的叮i*)的田间统计和对土壤、植物营养、/h麦产量、病害、昆虫、线虫、微生物和杂草的研究(例子见Bawden)。 展开更多
关键词 BROAD balk Gilbrt Lawcs 植物营养 因子设计 费歇尔 Gilbert 土壤分析 ECOLOGY 样地
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Improved electromagnetic dissipation of Fe doping LaCoO_(3)toward broadband microwave absorption 被引量:11
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作者 Fan Wang Weihua Gu +4 位作者 Jiabin Chen Qianqian Huang Mingyang Han Gehuan Wang Guangbin Ji 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第10期92-100,共9页
Perovskite LaCoO_(3)is of great potential in electromagnetic wave absorption considering its outstanding dielectric loss as well as the existing magnetic response with the magnetic doping.However,the dissipation mecha... Perovskite LaCoO_(3)is of great potential in electromagnetic wave absorption considering its outstanding dielectric loss as well as the existing magnetic response with the magnetic doping.However,the dissipation mechanism of the magnetic doping on the microwave absorption is lack of sufficient investigated.In this paper,LaCo_(1-x)Fe_(x)O_(3)(x=0,0.05,0.1,0.15,0.2,0.25,0.3,LCFOs)perovskites with different Fe doping amounts were prepared successfully by the sol-gel method and subsequent heat treatment in the air atmosphere.The structure characterization carried out by the frst-principles calculations shows the effect of Fe doping on the dielectric and magnetic properties of LCFOs and the strong hybridization of Co/Fe-3d with O-2p in the LCFOs system was successfully demonstrated.Particularly,when x=0.1 and the thickness is only 1.95 mm,the LaCo_(0.9)Fe_(0.1)O_(3)exhibits the best microwave absorption performance with the minimum reflection loss(RL)value of about-41 dB.The typical samples achieve a broad effective absorption bandwidth(EAB)of 5.16 GHz(7.92-13.08 GHz),which covers the total X band(8-12 GHz).Considering that,the especial Fe doping perovskite is promising to be a candidate as efficient microwave absorbers. 展开更多
关键词 Perovskites LaCoO_(3) Magnetic doping FIRST-PRINCIPLES Electromagnetic wave absorption Broad bandwidth
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Hierarchically porous carbon derived from natural Porphyra for excellent electromagnetic wave absorption 被引量:7
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作者 Juhua Luo Ziyang Dai +3 位作者 Mengna Feng Xiaowen Chen Caihong Sun Ying Xu 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第34期206-214,共9页
A highly efficient absorber with features including lightweight, broad bandwidth, and tunable electromagnetic property still remains challenging for practical applications. Herein, the Porphyra-derived porous carbon(P... A highly efficient absorber with features including lightweight, broad bandwidth, and tunable electromagnetic property still remains challenging for practical applications. Herein, the Porphyra-derived porous carbon(PPC) was fabricated via facile procedures of low-temperature pre-carbonization combined with KOH chemical activation. The composition, microstructure, and electromagnetic wave absorption properties of the samples were elucidated based on X-ray diffraction(XRD), Raman, X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), transmission electron microscopy(TEM),Brunauer-Emmer-Teller(BET), and vector network analyzer(VNA). The porosity of PPC can be readily regulated by adjusting activation temperature. The PPC obtained at 750 ℃ was composed of a threedimensional hierarchically porous carbon network. The C and N elements of natural Porphyra were introduced into the carbon skeleton during the carbonization process. The large specific surface, dopants, and three-dimensional hierarchically porous carbon network can effectively improve the impedance matching and dielectric dissipation, leading to an excellent electromagnetic wave absorption performance. Especially, the optimal reflection loss(RL) value reached –57.75 d B at 9.68 GHz with a broad bandwidth(RL< –10 d B) value of 7.60 GHz at 3.5 mm. Overall, the results indicate that the PPC can provide a new way to achieve lightweight, effective, and sustainable absorbers. 展开更多
关键词 Porphyra-derived carbon Hierarchically porosity Electromagnetic wave absorption Broad bandwidth Lightweight
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