Fiber and Integrated Optics最新文献

筛选
英文 中文
Suppression of third-order intermodulation distortion in analog photonic link based on dual-parallel Mach-Zehnder modulators 基于双平行马赫-曾德尔调制器的模拟光子链路三阶互调失真抑制
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-11-30 DOI: 10.1080/01468030.2021.2005185
Mingwei Gao, Jianxin Ma
{"title":"Suppression of third-order intermodulation distortion in analog photonic link based on dual-parallel Mach-Zehnder modulators","authors":"Mingwei Gao, Jianxin Ma","doi":"10.1080/01468030.2021.2005185","DOIUrl":"https://doi.org/10.1080/01468030.2021.2005185","url":null,"abstract":"<p><b>ABSTRACT</b></p><p>A linearization scheme for the microwave photonic link based on dual-parallel Mach–Zehnder modulator is proposed, which can suppress the third-order intermodulation distortion (IMD3) introduced by the nonlinearity of the electrooptical modulator and thus improve the spurious-free dynamic range (SFDR). By adjusting the optical power splitter, phase shifter, one of the three main factors that produce IMD3 can superimpose destructively with the other two. Theoretical analysis and simulation results show that our proposed scheme has a better electrical signal-to-interference ratio of 24.9 dB than the conventional scheme, and thus the SFDR has a 9 dB·Hz<sup>2/3</sup> improvement. In addition, in the back-to-back system, the error vector magnitude of a 250-MSym/s 16-quadrature-amplitude-modulation is reduced to 2.98% in our proposed scheme compared with the conventional scheme of 14.17%.</p>","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138508561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Evanescent Field Absorption-Based Fiber Optic Sensor for Detecting Power Transformer Oil Degradation 基于倏逝场吸收的光纤传感器用于电力变压器油退化检测
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-11-12 DOI: 10.1080/01468030.2021.2001878
Ş. Hayber, T. Tabaru, Mehmet Güçyetmez
{"title":"Evanescent Field Absorption-Based Fiber Optic Sensor for Detecting Power Transformer Oil Degradation","authors":"Ş. Hayber, T. Tabaru, Mehmet Güçyetmez","doi":"10.1080/01468030.2021.2001878","DOIUrl":"https://doi.org/10.1080/01468030.2021.2001878","url":null,"abstract":"Observing the transformer oil quality is essential for the transformer’s health and system. The aging state of the transformer oils and the average remaining life accordingly can be determined using the breakdown voltage (BDV) test, ultraviolet-visible (UV-Vis) spectroscopy, and the refractive index (RI) standard methods. The subject of this study is to design and manufacture a much simpler and low-cost, evanescent field absorptionbased fiber optic sensor (EFA-FOS) compatible with these proven standard methods and to perform a comparative performance analysis by determining a critical voltage threshold. Apart from the expensive and cumbersome standard methods mentioned above, the usability of the oil is carried out, thanks to the online sensor system, with the pretest using this critical voltage value. EFA-FOS measurement results of oil samples can determine the samples’ aging degree with high accuracy. The samples’ RI is determined with EFA-FOS with a sensitivity of −70 V/RIU and a linearity of 0.98 (R). A strong relationship has also been determined between the sensor output and measured BDV with a regression constant of 0.86 (R). ARTICLE HISTORY Received 30 April 2021 Accepted 31 October 2021","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91180855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 6
Review of OFC 2021: The future of optical networks and communications. Virtual conference 6–10 June 2021 OFC 2021回顾:光网络和通信的未来。虚拟会议2021年6月6日至10日
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-11-02 DOI: 10.1080/01468030.2021.2013657
H. Hodara, P. Mock, C. Slemon
{"title":"Review of OFC 2021: The future of optical networks and communications. Virtual conference 6–10 June 2021","authors":"H. Hodara, P. Mock, C. Slemon","doi":"10.1080/01468030.2021.2013657","DOIUrl":"https://doi.org/10.1080/01468030.2021.2013657","url":null,"abstract":"ABSTRACT This is a detailed review of the latest developments presented at the last OFC 2921 virtual conference. The review covers: Game-Changing developments, specifically Hollow Core Fibers (HCF), Neural Networks (NN) Applications, and Quantum Key Distribution (QKD); and Incremental developments, in particular, Sensors and Data Centers, High-Speed Coherent Optics Transmission, with the latter’s emphasis on Optical Switching.","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74816184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Flexible Multi-band Dual-chirped Microwave Waveforms Generation with Double Bandwidth 双带宽柔性多波段双啁啾微波波形生成
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-11-02 DOI: 10.1080/01468030.2021.2014606
H. Zhang, J. Ma, Junyi Zhang
{"title":"Flexible Multi-band Dual-chirped Microwave Waveforms Generation with Double Bandwidth","authors":"H. Zhang, J. Ma, Junyi Zhang","doi":"10.1080/01468030.2021.2014606","DOIUrl":"https://doi.org/10.1080/01468030.2021.2014606","url":null,"abstract":"ABSTRACT A multi-band dual-chirp linearly frequency modulated (LFM) signal-generation scheme with doubled chirp bandwidth and flexible center frequency and band numbers is proposed. In the scheme, the polarization multiplexed multi-tone optical signals with chirped phases are generated via a dual-polarization dual-parallel Mach–Zehnder modulator (DPMZM) cascaded with a polarization modulator. The two polarization multiplexed lightwaves are recombined as two linearly polarized beams by a polarization beam splitter and are detected by a balanced photodiode with a photocurrent that includes the multi-band dual-chirp LFM signal with doubled bandwidth and multiplied central frequencies but does not have a dc component. Since the orders and numbers of the generated optical sidebands are changed by adjusting the bias voltages of a DPMZM, we can obtain the multi-band dual-chirp LFM signal flexibly. Based on simulation, four-band, six-band and two seven-band dual-chirp LFM signals are generated with four groups of bias voltage configurations. For each case, every dual-chirp LFM signal of the generated multi-band dual-chirp LFM signal has a 5-GHz bandwidth and a time-bandwidth product of 512. The auto-correlations and ambiguity function of the generated LFM signal show good performance of pulse compression and range-Doppler resolution.","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73773051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Dark Pulse Mode-locked Laser based on Aluminum Zinc Oxide coated D-shape fiber as Saturable Absorber 基于锌铝包覆d型光纤作为可饱和吸收剂的暗脉冲锁模激光器
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-11-01 DOI: 10.1080/01468030.2021.1995084
B. Nizamani, A. Jafry, G. Fizza, F. A. Memon, S. Salam, M. Najm, M. A. Abdul Khudus, E. Hanafi, R. Apsari, S. Harun
{"title":"Dark Pulse Mode-locked Laser based on Aluminum Zinc Oxide coated D-shape fiber as Saturable Absorber","authors":"B. Nizamani, A. Jafry, G. Fizza, F. A. Memon, S. Salam, M. Najm, M. A. Abdul Khudus, E. Hanafi, R. Apsari, S. Harun","doi":"10.1080/01468030.2021.1995084","DOIUrl":"https://doi.org/10.1080/01468030.2021.1995084","url":null,"abstract":"ABSTRACT We have experimentally reported aluminum zinc oxide (AZO) as a novel saturable absorber to generate a mode-locked laser operating in dark pulsed regime. The D-shaped fiber was first prepared by side polishing a single-mode fiber to the 1 dB insertion loss. The AZO was dissolved in isopropyl alcohol and then deposited onto the D-shaped fiber by drop casting method. By carefully optimizing the polarization of the cavity, a dark pulse was achieved, which remained stable within the pump power of 65.7–101.35 mW. Pulse width was 220 ns, and the pulse repetition rate was 1.85 MHz.","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85019470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Performance Analysis Of Optical Modulation Techniques Based On Reduction Of Second Order Harmonics And Chromatic Dispersion on OFDM Signals 基于降低二阶谐波和色散的OFDM信号光调制技术性能分析
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-10-12 DOI: 10.1080/01468030.2021.1945171
Apoorv Kulkarni, Shrey Kothavade, Dhananjay Patel, Rajat Jain
{"title":"Performance Analysis Of Optical Modulation Techniques Based On Reduction Of Second Order Harmonics And Chromatic Dispersion on OFDM Signals","authors":"Apoorv Kulkarni, Shrey Kothavade, Dhananjay Patel, Rajat Jain","doi":"10.1080/01468030.2021.1945171","DOIUrl":"https://doi.org/10.1080/01468030.2021.1945171","url":null,"abstract":"ABSTRACT This work explains the theoretical and mathematical investigations of the transmission performance of an optical Single Sideband (SSB) modulation technique generated by a Mach Zehnder Modulator (MZM) with a 90° and 120° phase shift using hybrid coupler (Modified SSB) in addition to the Vestigial Sideband technique (VSB). The problem addressed in this paper is the effect of non-linearity of the transmitter system and the chromatic dispersion in single mode fiber due to the presence of second- and higher order harmonics. The non-linearity of the transmitter generates second and higher order harmonics, which affects the system performance leading to reduction in the data rate and increased distortion. The transmission performance of SSB, M-SSB and VSB is evaluated based on the extinction ratio of the MZM, different transmission lengths of the fiber, optical signal modulation index and the receiver sensitivity. A mathematical model has been developed for all the systems representing the modulation techniques till the second order. The baseband modulation consists of an RF signal of frequency 18 GHz and an Orthogonal Frequency Division Multiplexing (OFDM) signal with 4-QAM modulation technique converted to optical signal, using the MZM and transmitted over a SMF of distance of 75 Km. Our results show that the M-SSB technique proves to be more immune toward transmitter nonlinearity and chromatic dispersion as compared to its counterparts. In addition to this, it improves the receiver sensitivity by 6.56 dBm. The results generated by software simulation are in tandem with the mathematical model.","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80635720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Sodium Carbonate for Generating Q-Switched Pulses in 1550 nm Region 碳酸钠在1550nm区域产生调q脉冲
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-06-22 DOI: 10.1080/01468030.2021.1942334
M. Najm, B. Nizamani, Pei Zhang, S. Salam, H. Arof, Norrima Mokhtar, A. Al-Hiti, M. Yasin, S. Harun
{"title":"Sodium Carbonate for Generating Q-Switched Pulses in 1550 nm Region","authors":"M. Najm, B. Nizamani, Pei Zhang, S. Salam, H. Arof, Norrima Mokhtar, A. Al-Hiti, M. Yasin, S. Harun","doi":"10.1080/01468030.2021.1942334","DOIUrl":"https://doi.org/10.1080/01468030.2021.1942334","url":null,"abstract":"ABSTRACT In this study, we have experimentally demonstrated the sodium carbonate (Na₂CO₃) thin-film as a saturable absorber (SA) for Q-switched laser generation in erbium-doped fiber laser (EDFL) cavity. The Na₂CO₃ powder was embedded in polyvinyl alcohol (PVA) to fabricate the thin film. The Na2CO3 was then employed in an EDFL cavity for passively generating Q-switched pulses with a minimum pulse width of 1.2 µs and maximum repetition rate of 94.7 kHz. The fundamental frequency of 94.7 kHz had the signal to noise ratio of 73.51 dB, which indicates the pulses were stable. The Q-switched laser operated at center wavelength of 1560 nm.","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73204138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
From 1G to 5G 从1G到5G
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-05-04 DOI: 10.1080/01468030.2021.1919358
H. Hodara, E. Skaljo
{"title":"From 1G to 5G","authors":"H. Hodara, E. Skaljo","doi":"10.1080/01468030.2021.1919358","DOIUrl":"https://doi.org/10.1080/01468030.2021.1919358","url":null,"abstract":"ABSTRACT Wireless Mobile Communications have undergone major “generational” changes since MacDonald of Bell Telephone Laboratories introduced the concept of cellular communications in 1979. Over the last four decades, the technology has evolved from the first generation, 1 G, followed by 2 G, 3 G, and 4 G, to reach today’s threshold of the fifth generation, 5 G. In order to grasp the magnitude of the impact 5 G is having on our society (5 G internet is expected cover up to 65% of the world’s population by the end of 2025!), it is essential to understand the historical development of the previous generations. This review describes and explains the technology from 1 G to 4 G, culminating with the current state-of-the-art of 5 G, and its expected performance over the next ten years. We cover the major technical features of 5 G that differentiate them from the previous generations, in particular,the introduction of the MM-Wave spectrum combined with MIMO, Multiple Input-Multiple Output antenna arrays. We single out these two features as they provide orders of magnitude increases in channel capacity (20 Gb/s Downlink data transfer rates with reduced latency of 1 ms) and internet connectivity on the order of billions. We conclude with related 5 G marketing data, some of it related to the smart phone, a marvel of engineering and a credit to human creativity. 5 G is committed to connecting billions of devices with billions of people, both wirelessly and via the internet. Such a technical advance is a game-changer!","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90565059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 18
Polarization Beam Splitter Based on the Gold Wire-Filled Dual-Core Photonic Crystal Fiber at the Communication Wavelengths 通信波长上基于金线填充双芯光子晶体光纤的偏振分束器
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-01-02 DOI: 10.1080/01468030.2021.1882621
Yongxia Zhang, Yuwei Qu, J. Yuan, Haiyun Wang, Xian Zhou, Jiahao Huo, B. Yan, Qiang Wu, Kuiru Wang, Keping Long, Chongxiu Yu
{"title":"Polarization Beam Splitter Based on the Gold Wire-Filled Dual-Core Photonic Crystal Fiber at the Communication Wavelengths","authors":"Yongxia Zhang, Yuwei Qu, J. Yuan, Haiyun Wang, Xian Zhou, Jiahao Huo, B. Yan, Qiang Wu, Kuiru Wang, Keping Long, Chongxiu Yu","doi":"10.1080/01468030.2021.1882621","DOIUrl":"https://doi.org/10.1080/01468030.2021.1882621","url":null,"abstract":"ABSTRACT In this paper, a polarization beam splitter (PBS) based on the gold wire-filled dual-core photonic crystal fiber is proposed. The full-vector finite element method is used to investigate the influences of the fiber structure parameters on the transmission characteristics and coupling length. By appropriately adjusting the fiber structure parameters, the coupling length ratio of 2:1 can be achieved at wavelengths 1.55 and 1.31 μm, so the incident light can be well separated into the two beams with orthogonal polarization states. When the fiber length is 805.3 μm, the maximum extinction ratio (ER) within bandwidth of 60 nm is −132.12 dB at wavelength 1.55 μm. When the fiber length is 1264.9 μm, the maximum ER within bandwidth of 70 nm is −197 dB at wavelength 1.31 μm. By optimizing the fiber structure parameters, a PBS with a length of 249.12 μm, the maximum ER of −112.2 dB, and bandwidth of 120 nm can be obtained.","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88719386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
The Temperature Effect on U and Coil Shaped POF Sensors to Detect Refractive Index Change 温度对U形和线圈形POF传感器折射率变化的影响
IF 1.7 4区 物理与天体物理
Fiber and Integrated Optics Pub Date : 2021-01-02 DOI: 10.1080/01468030.2021.1904059
T. Tabaru
{"title":"The Temperature Effect on U and Coil Shaped POF Sensors to Detect Refractive Index Change","authors":"T. Tabaru","doi":"10.1080/01468030.2021.1904059","DOIUrl":"https://doi.org/10.1080/01468030.2021.1904059","url":null,"abstract":"ABSTRACT The effect of the temperature on refractive index (RI) sensors based on U and Coil-shaped plastic optical fiber (POF) was investigated. For this purpose, four POF-RI sensor probes were produced, and RI changes caused by ethanol changes in solutions were detected. Two of the produced probes were U-shaped, while the other two were Coil-shaped. For the first time in the literature, the effect of both the geometry of the U and Coil-shaped POF-RI sensors on the sensor parameters and the effect of the medium temperature have been analyzed together. As a result of the experiments conducted at 25°C, the best RI change detection sensitivity, linearity, and resolution values were determined as 821%/RIU, 0.9974 (R2), 5.18 × 10−4. In addition, temperature dependence loss (TDL) and temperature dependence RI deviation (TDR) were measured at different temperatures (25–40°C) in the 1.3346–1.45 RI range, and the effect of temperature change on POF-RI sensor probes was characterized.","PeriodicalId":50449,"journal":{"name":"Fiber and Integrated Optics","volume":null,"pages":null},"PeriodicalIF":1.7,"publicationDate":"2021-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79154716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
0
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
确定
请完成安全验证×
相关产品
×
本文献相关产品
联系我们:info@booksci.cn Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。 Copyright © 2023 布克学术 All rights reserved.
京ICP备2023020795号-1
ghs 京公网安备 11010802042870号
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术官方微信