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Learning to synthesize:robust phase retrieval at low photon counts 被引量:6
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作者 Mo Deng Shuai Li +2 位作者 Alexandre Goy Iksung Kang George Barbastathis 《Light(Science & Applications)》 SCIE EI CAS CSCD 2020年第1期1657-1672,共16页
The quality of inverse problem solutions obtained through deep learning is limited by the nature of the priors learned from examples presented during the training phase.Particularly in the case of quantitative phase r... The quality of inverse problem solutions obtained through deep learning is limited by the nature of the priors learned from examples presented during the training phase.Particularly in the case of quantitative phase retrieval,spatial frequencies that are underrepresented in the training database,most often at the high band,tend to be suppressed in the reconstruction.Ad hoc solutions have been proposed,such as pre-amplifying the high spatial frequencies in the examples;however,while that strategy improves the resolution,it also leads to high-frequency artefacts,as well as low-frequency distortions in the reconstructions.Here,we present a new approach that learns separately how to handle the two frequency bands,low and high,and learns how to synthesize these two bands into full-band reconstructions.We show that this“learning to synthesize”(LS)method yields phase reconstructions of high spatial resolution and without artefacts and that it is resilient to high-noise conditions,e.g.,in the case of very low photon flux.In addition to the problem of quantitative phase retrieval,the LS method is applicable,in principle,to any inverse problem where the forward operator treats different frequency bands unevenly,i.e.,is ill-posed. 展开更多
关键词 SYNTHESIZE BANDS PHASE
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Impact of black cherry on pedunculate oak vitality in mixed forests:Balancing benefits and concerns
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作者 Ellen Desie Bart Muys +8 位作者 Jan den Ouden Bart Nyssen Rita Sousa-Silva Leon van den Berg Arnold van den Burg Gert-Jan van Duinen Koenraad Van Meerbeek Maaike Weijters Karen Vancampenhout 《Forest Ecosystems》 SCIE CSCD 2023年第6期690-699,共10页
The vitality of European forests continues to decline due to new pests and diseases,climate-change related disturbances and high loads of atmospheric nitrogen deposition.Deteriorating soil health is a major factor und... The vitality of European forests continues to decline due to new pests and diseases,climate-change related disturbances and high loads of atmospheric nitrogen deposition.Deteriorating soil health is a major factor underpinning the low vitality of West-European forests.Selecting tree species with soil ameliorative traits is proposed as an avenue to counteract soil acidification and improve overall forest vitality.Here we evaluate the impact of black cherry(Prunus serotina Ehrh.),a known rich litter species,on the vitality of neighboring pedunculate oak(Quercus robur L.)in ten mixed forests on sand in Germany,Belgium and the Netherlands.We found that black cherry admixture increases foliar N and P to a surplus whereas it causes deficiencies in foliar Mg,thereby resulting in an overall negative effect on oak foliar nutrient concentrations.Contrary,defoliation of oak leaves by herbivory decreases with the proximity of black cherry.Using structural equation modelling(SEM),we tested the hypothesized‘improved soil health’pathway.Our analyses showed that black cherry admixture leads to lower accumulation in the humus layer,resulting in higher soil base saturation which has a positive effect on foliar Ca yet a negative effect on total chlorophyll.Moreover,the SEM illustrated that herbivory of oak leaves decreases when black cherry is admixed,both via dilution and improved soil health.Indirect effects of black cherry on oak vitality via“improved soil health”in our SEM are however small in comparison to direct relations.Hence,our study showed that the combined positive and negative impacts of black cherry on oak vitality are limited,which tempers the potential benefits of using the rich litter species to counteract oak decline via improved soil health–yet,the concern of black cherry as an invasive alien species negatively affecting the vitality of mature pedunculate oak trees may also be exaggerated. 展开更多
关键词 Rich litter species Black cherry Nutrient cycling Insect herbivory Dilution effect Humus type Pedunculate oak Plant-soil interaction
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Diagnostic Validity of Cica Beta Test 1 for the Detection of Extended Spectrum Beta-Lactamase (ESBL) Producing Gram Negative Bacteria by Comparing with Phenotypic Method
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作者 Mostaqimur Rahman Hafiza Sultana +2 位作者 Abdullahil Mosawuir Latifa Akhter Abdullah Yusuf 《Advances in Infectious Diseases》 2019年第1期39-48,共10页
Background: Detection of extended spectrum beta lactamase producing bacteria is an important issue in the clinical settings. Objective: The purpose of the present study was to validate the Cica Beta Test 1 for detecti... Background: Detection of extended spectrum beta lactamase producing bacteria is an important issue in the clinical settings. Objective: The purpose of the present study was to validate the Cica Beta Test 1 for detection of extended spectrum beta-lactamase (ESBL) producing bacteria. Method: This analytical type of cross-sectional study was carried out in the Department of Microbiology and Immunology at Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka from January 2006 to December 2006 for a period of one (01) year. All the patients presented with the clinical features of urinary tract infection and surgical as well as burn wound infection at any age with both sexes were selected as study population. All bacteria were isolated and identified by their colony morphology, staining characters, pigment production, motility and other relevant biochemical tests. Phenotypic confirmation of ESBLs producing isolates were done by inhibitor potentiated disc diffusion test according to CLSI recommendation. The Cica Beta Test 1 was performed according to the manufacturer’s instructions. Result: A total number of 288 Gram negative bacteria were isolated. Among these isolates Cica Beta test 1 was positive in 97 strains and phenotypic confirmatory test was positive in 89 strains. The test sensitivity of Cica Beta Test 1 was 100% (95% CI 95.9% to 100.0%). Specificity of the test was 96.0% (95% CI 92.2% to 98.2%). The positive predictive value (PPV) and negative predictive value (NPV) were 92.7% (95% CI 84.5% to 95.7%) and 100.0% (95% CI 98.0% to 100.0%) respectively. The accuracy of the test was 97.2% (95% CI 95.1% to 99.1%). Area under ROC curve = 0.980 (95% CI 0.964 to 0.996);p value 0.0001. Conclusion: In conclusion, Cica Beta Test 1 is very high sensitivity and specificity for the detection of ESBL from Gram negative bacteria. 展开更多
关键词 Diagnostic Validity Cica BETA Test 1 EXTENDED SPECTRUM BETA-LACTAMASE ESBL Gram Negative Bacteria PHENOTYPIC Method
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STUDY ON HEMODYNAMICS OF ERECTION IN DIABETIC ERECTILE DYSFUNCTION
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作者 傅强 姚德鸿 蒋跃庆 《Journal of Shanghai Second Medical University(Foreign Language Edition)》 2004年第2期121-124,共4页
Objective To study the cavernosa hemodynamics in diabetic erectile dysfunction ( ED).Methods 22 diabetic and 35 psychic ED patients were studied by intracavernosum injection of a mixture papaver-ine and phentolamine (... Objective To study the cavernosa hemodynamics in diabetic erectile dysfunction ( ED).Methods 22 diabetic and 35 psychic ED patients were studied by intracavernosum injection of a mixture papaver-ine and phentolamine (30/1mg) to assess the hemodynamics changes of the corpus cavernosum by means of colour duplex ultrasonography. Results The average hemodynamics data of the diabetic ED patients vs that of the psy-chogenic ED patients in terms of peak flow velocity (PFV):20. 06±7.15cm/s vs 35. 82±9. 41cm/s, end diastolic velocity (EDV) : 8. 82±0. 35cm/s vs 5. 51±0. 42cm/s,artery diameter (Ad) : 0. 78±0. 25cm vs 1. 01±0. 42cm, vein diameter ( Vd) : 1.05±0. 32mm vs 1.21±0. 45mm, resistance index(RI) : 0. 72±0. 28 vs 0. 98±0. 31,mean velocity of artery (MV):6. 71±0. 27cm/s vs 10. 31±3. 32cm/s, dorsal deep vein flow(DDVF) : 28. 81±6. 32cm/ s vs 25. 74±0. 58cm/s. Stasticstical differences existed in PFV, Ad,RI and MV(P <0. 01). The arterial wall is thick and rigid in diabetic ED patients. Conclusion Atheroscleorsis and veno-occlusive dysfunction of the corpus cavernosum are essential to the development of diabetic ED. 展开更多
关键词 diabetes mellitus erectile dysfunction colour duplex ultrasonography
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Heuristic Estimation of the Vacuum Energy Density of the Universe: Part II-Analysis Based on Frequency Domain Electromagnetic Radiation
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作者 Vernon Cooray Gerald Cooray +1 位作者 Marcos Rubinstein Farhad Rachidi 《Journal of Electromagnetic Analysis and Applications》 2024年第1期1-9,共9页
In Part I of this paper, an inequality satisfied by the vacuum energy density of the universe was derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according ... In Part I of this paper, an inequality satisfied by the vacuum energy density of the universe was derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an electron is accelerated to a constant and relativistic speed at a distance L from a perfectly conducting plane. The charge of the electron was represented by a spherical charge distribution located within the Compton wavelength of the electron. Subsequently, the electron is incident on the perfect conductor giving rise to transition radiation. The energy associated with the transition radiation depends on the parameter L. It was shown that an inequality satisfied by the vacuum energy density will emerge when the length L is pushed to cosmological dimensions and the product of the radiated energy, and the time duration of emission is constrained by Heisenberg’s uncertainty principle. In this paper, a similar analysis is conducted with a chain of electrons oscillating sinusoidally and located above a conducting plane. In the thought experiment presented in this paper, the behavior of the energy radiated by the chain of oscillating electrons is studied in the frequency domain as a function of the length L of the chain. It is shown that when the length L is pushed to cosmological dimensions and the energy radiated within a single burst of duration of half a period of oscillation is constrained by the fact that electromagnetic energy consists of photons, an inequality satisfied by the vacuum energy density emerges as a result. The derived inequality is given by where is the vacuum energy density. This result is consistent with the measured value of the vacuum energy density, which is 5.38 × 10<sup>-10</sup> J/m. The result obtained here is in better agreement with experimental data than the one obtained in Part I of this paper with time domain radiation. 展开更多
关键词 Classical Electrodynamics Electromagnetic Radiation Action Radiated Energy PHOTON Heisenberg’s Uncertainty Principle Dark Energy Vacuum Energy Cosmological Constant Hubble Radius
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Heuristic Estimation of the Vacuum Energy Density of the Universe: Part I—Analysis Based on Time Domain Electromagnetic Radiation
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作者 Vernon Cooray Gerald Cooray +1 位作者 Marcos Rubinstein Farhad Rachidi 《Journal of Electromagnetic Analysis and Applications》 2023年第6期73-81,共9页
In this paper, an inequality satisfied by the vacuum energy density of the universe is derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an... In this paper, an inequality satisfied by the vacuum energy density of the universe is derived using an indirect and heuristic procedure. The derivation is based on a proposed thought experiment, according to which an electron is accelerated to a constant and relativistic speed at a distance L from a perfectly conducting plane. The charge of the electron is represented by a spherical charge distribution located within the Compton wavelength of the electron. Subsequently, the electron is incident on the perfect conductor giving rise to transition radiation. The energy associated with the transition radiation depends on the parameter L. It is shown that an inequality satisfied by the vacuum energy density will emerge when the length L is pushed to cosmological dimensions and the product of the radiated energy and the time duration of emission are constrained by Heisenberg’s uncertainty principle. The inequality derived is given by ρ<sub>Λ</sub> ≤ 9.9×10<sup>-9</sup>J/m<sup>3</sup> where ρ<sub>Λ </sub>is the vacuum energy density. This result is consistent with the measured value of the vacuum energy density, which is 0.538 × 10<sup>-9</sup>J/m. Since there is a direct relationship between the vacuum energy density and the Einstein’s cosmological constant, the inequality can be converted directly to that of the cosmological constant. 展开更多
关键词 Classical Electrodynamics Electromagnetic Radiation Action Radiated Energy PHOTON Heisenberg’s Uncertainty Principle Dark Energy Vacuum Energy Cosmological Constant Hubble Radius
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Hints of the Photonic Nature of the Electromagnetic Fields in Classical Electrodynamics
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作者 Vernon Cooray Gerald Cooray +1 位作者 Marcos Rubinstein Farhad Rachidi 《Journal of Electromagnetic Analysis and Applications》 2023年第3期25-42,共18页
Several recent publications show that the electromagnetic radiation generated by transmitting antennas satisfy the following universal conditions: The time domain radiation fields satisfy the condition A ≥ h/4π &... Several recent publications show that the electromagnetic radiation generated by transmitting antennas satisfy the following universal conditions: The time domain radiation fields satisfy the condition A ≥ h/4π &Rightarrow;q ≥ e where A is the action of the radiation field, which is defined as the product of the radiated energy and the duration of the radiation, h is the Planck constant, e is the electronic charge and q is the charge associated with the radiating system. The frequency domain radiation fields satisfy the condition U ≥ hv &Rightarrow;q ≥ e where U is the energy radiated in a single burst of radiation of duration T/2 and v is the frequency of oscillation. The goal of this paper is to show that these conditions, which indeed are expressions of the photonic nature of the electromagnetic fields, are satisfied not only by the radiation fields generated by physical antennas but also by the radiation fields generated by accelerating or decelerating electric charges. The results presented here together with the results obtained in previous studies show that hints of the photonic nature of the electromagnetic radiation remain hidden in the field equations of classical electrodynamics, and they become apparent when the dimension of the radiating system is pushed to the extreme limits as allowed by nature. 展开更多
关键词 Classical Electrodynamics Electromagnetic Radiation Action Radiated Energy PHOTON Heisenberg’s Uncertainty Principle Dark Energy Vacuum Energy Hubble Radius
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用于精确运动和安全定时的实时以太网——SERCOS Ⅲ 被引量:2
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作者 伯纳德.施耐德 彼得.陆茨 王锡俊 《国内外机电一体化技术》 2008年第2期4-7,共4页
作为实现新一代创新立异的机器概念(它基于智能的网络化的自动化组件)的前提条件,通信接口不仅要又快又准时,而且还要同步工作。在实时以太网解决方案SERCOSⅢ中,一个简单而高效的同步方法保证了各网络单元不但同步而且并发地运转... 作为实现新一代创新立异的机器概念(它基于智能的网络化的自动化组件)的前提条件,通信接口不仅要又快又准时,而且还要同步工作。在实时以太网解决方案SERCOSⅢ中,一个简单而高效的同步方法保证了各网络单元不但同步而且并发地运转。SERCOSⅢ同步过程适用于线型和环型拓扑结构。即使拓扑结构发生变化(如:冗余、热插拔),其精度也保持不变。 展开更多
关键词 SERCOS 实时以太网 定时 安全 运动 同步工作 拓扑结构 自动化组件
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1例瘤型麻风(多菌型)患者的组织样麻风病变(新生)
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作者 Seghal V.N. Aggarwal A. +1 位作者 Srivastava G. 刘安 《世界核心医学期刊文摘(皮肤病学分册)》 2005年第12期4-5,共2页
A 26- year- old man presented with persistent redness of the face over the past 2 years and thickening of the ears for a year. The current state was preceded by three to four episodes of epistaxis, 2- 3 months previou... A 26- year- old man presented with persistent redness of the face over the past 2 years and thickening of the ears for a year. The current state was preceded by three to four episodes of epistaxis, 2- 3 months previously. The patient had not received any treatment. Cutaneous examination revealed indurated (infiltrated) plaques on the face and ears over an apparently normal- looking skin, and numerous, small, ill- defined, slightly hypopigmented, shiny macules all over the body. They were bilateral and symmetric (Fig. 1a,b). There was no variation in the cutaneous sensations of temperature, touch, and pain. The patient showed loss of the lateral eyebrows and conjunctival congestion. Examination of the nerves revealed enlargement of the ulnar, radial, posterior tibial, and right common peroneal nerves; however, there was no tenderness of the nerves. Systemic examination was within normal limits. Examination of a slit- skin smear (under oil immersion), prepared from a representative lesion (plaque), demonstrated an abundance of solid and uniform- staining acid- fast bacilli, occurring either singly or in parallel clumps/globii, in an average field (6+ ). Furthermore, a scraping mount (10% KOH) prepared from the lesion on the back was negative. Hematoxylin and eosin- stained sections prepared from a biopsy taken from a plaque revealed a conspicuous granuloma composed of peculiar spindle- shaped histiocytes. Several of the granulomas were present in the mid and lower dermis. They were characterized by whorled, criss- cross, or parallel patterns. Solid and uniform- staining, slender, rod- like (length three times that of the breadth) acidfast bacilli were found scattered throughout the section. A few histiocytes closely packed with acid- fast bacilli, together with lymphocytic infiltrates, were also seen. There was a prominent eosinophilic stained clear zone just below the epidermis. It was free from acid- fast bacilli as well as the inflammatory infiltrate (Fig. 2a,b). A definitive diagnosis of untreated lepromatous l 展开更多
关键词 多菌型 瘤型麻风 抗酸杆菌 涂片检查 皮肤温度觉 色减斑 胫后神经 典型皮损 耳部皮肤 腓总神经
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Female Entrepreneurship in Switzerland: Specificities and Differences
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作者 Mathias Rossi Silna Borter, Marie Sansonnens 《Journal of Modern Accounting and Auditing》 2012年第8期1225-1236,共12页
Women entrepreneurs are increasingly representing an underexploited potential of the Swiss economy. Although entrepreneurship represents a rapidly expanding phenomenon, women meet specific difficulties that explain th... Women entrepreneurs are increasingly representing an underexploited potential of the Swiss economy. Although entrepreneurship represents a rapidly expanding phenomenon, women meet specific difficulties that explain this lack of exploitation by the economy, The Global Entrepreneurship Monitor (GEM), a not-for-profit academic research consortium, published its annual report which mentioned in particular a difference between female and male entrepreneurship. According to these results, it can be noticed that the typical profile of the female entrepreneur differs from that of her male counterpart. In Switzerland, those differences can be situated at three levels: (I) In the first place, a natural difference of the female entrepreneurship at the level of activities (service activities, low-added value, and low potential of job creation); (2) Secondly, a difference in motivation/commitment (part-time work, start-up funds available, skills, received opportunities, and fear of failure); and (3) Thirdly, a difference at the level of insertion (revealing the importance of networking, access to financing and structures of encouragement). The present communication points up a typical profile of the woman entrepreneur in Switzerland. The authors also intend to identify the kind of obstacles female entrepreneur is likely to meet as well as the existing initiatives to exceed stereotypes by taking into account her specificities. There are several supports and measures intended to help women entrepreneurship concerning the following aspects: better time management; adapted following and training structures; access to easier financing; and better visibility and networking. 展开更多
关键词 ENTREPRENEURSHIP female entrepreneurship Swiss entrepreneurship GENDER gender differences
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麦角固醇光解生产维生素D2新工艺
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作者 林琳 《大化科技》 2004年第3期12-14,共3页
本工艺采用紫外光照法用麦角固醇生产维生素D2(简称VD2),并对其生产的条件进行了优化和比较,进行了工业化实验,得到了较好的结果。最终麦角固醇转化率为50%以上,维生素D2选择性得率为40%以上.达到了工业化的要求。
关键词 紫外光照法 麦角固醇 维生素D2 生产工艺 转化率 乙醇 光照时间 光反应 汞灯
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服务令产品物超所值
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作者 张国民 《教育技术资讯》 2005年第4期46-46,共1页
爱普生公司不但以领先的影像技术和稳定可靠的内在品质在诸多竞争者中独占鳌头,更以完备周到的售后服务领先于业界。爱普生是较早在国内建立投影机售后服务体系的品牌之一。至今,国内已经有25个主要城市建立了40佘家授权服务中心/站... 爱普生公司不但以领先的影像技术和稳定可靠的内在品质在诸多竞争者中独占鳌头,更以完备周到的售后服务领先于业界。爱普生是较早在国内建立投影机售后服务体系的品牌之一。至今,国内已经有25个主要城市建立了40佘家授权服务中心/站。专业培训的认证工程师、原厂提供的维修零备件、规范的维修服务管理,使服务质量和用户满意度逐年提高。对投影机类产品,爱普生除提供标准的2年整机保修、6个月的灯泡保修外,又采取了一系列新的服务举措: 展开更多
关键词 产品 售后服务体系 爱普生公司 用户满意度 内在品质 影像技术 服务领先 服务中心 主要城市 专业培训 服务管理 服务质量 服务举措 投影机 竞争者 工程师 零备件 国内 维修 保修 独占 品牌 授权
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