Mechanical behaviours of bedded sandstone under hydromechanical coupling

The combination of the dipping effect and hydromechanical(H-M)coupling effect can easily lead to water inrush disasters in water-rich roadways with different dip angles in coal mines.Therefore,H-M coupling tests of bedded sandstones under identical osmotic pressure and various confining pressures were conducted.Then,the evolution curves of stress-strain,permeability and damage,macro-and mesoscopic failure characteristics were obtained.Subsequently,the mechanical behaviour was characterized,and finally the failure mechanism was revealed.The results showed that:(1)The failure of the sandstone with the bedding angle of 45°or 60°was the structure-dominant type,while that with the bedding angle of 0°,30°or 90°was the force-dominant type.(2)When the bedding angle was in the range of(0°,30°)or(45°,90°),the confining pressure played a dominant role in influencing the peak strength.However,withinβ∈(30°,45°),the bedding effect played a dominant role in the peak strength.(3)With the increase in bedding angle,the cohesion increased first,then decreased and finally increased,while the internal friction angle was the opposite.(4)When the bedding angle was 0°or 30°,the“water wedging”effect and the“bedding buckling”effect would lead to the forking or converging shear failure.When the bedding angle was 45°or 60°,the sliding friction effect would lead to the shear slipping failure.When the bedding angle was 90°,the combination of the“bedding buckling”effect and shear effect would lead to the mixed tension-shear failure.The above conclusions obtained are helpful for the prevention of water inrush disasters in water-rich roadways with different dips in coal mines.

Photonics-assisted THz wireless communication enabled by wide-bandwidth packaged backilluminated modified uni-traveling-carrier photodiode

This paper presents a wide-bandwidth back-illuminated modified uni-traveling-carrier photodiode(MUTC-PD)packaged with standard WR-5 rectangular waveguide for high-speed wireless communications.With optimized epitaxy structure and coplanar waveguide electrodes,the fabricated 4-μm-diameter PD exhibits ultra-flat frequency response and high saturation power.Integrated passive circuits including low-loss bias-tee and E-plane probe are designed to package the PD into a compact module with waveguide output.The packaged PD module has demonstrated a flat frequency response with fluctuations within±2.75 d B over a broadband of 140–220 GHz and a high saturated output power of-7.8 d Bm(166μW)at 140 GHz.For wireless communication applications,the packaged PD is used to implement 1-m free space transmission at carrier frequencies of 150.5 and 210.5 GHz,with transmission rates of 75 and 90 Gbps,respectively.

Characterization and evaluation of brittleness of deep bedded sandstone from the perspective of the whole life-cycle evolution process

The quantitative determination and evaluation of rock brittleness are crucial for the estimation of excavation efficiency and the improvement of hydraulic fracturing efficiency.Therefore,a“three-stage”triaxial loading and unloading stress path is designed and proposed.Subsequently,six brittleness indices are selected.In addition,the evolution characteristics of the six brittleness indices selected are characterized based on the bedding effect and the effect of confining pressure.Then,the entropy weight method(EWM)is introduced to assign weight to the six brittleness indices,and the comprehensive brittleness index Bcis defined and evaluated.Next,the new brittleness classification standard is determined,and the brittleness differences between the two stress paths are quantified.Finally,compared with the previous evaluation methods,the rationality of the proposed comprehensive brittleness index Bcis also verified.These results indicate that the proposed brittleness index Bccan reflect the brittle characteristics of deep bedded sandstone from the perspective of the whole life-cycle evolution process.Accordingly,the method proposed seems to offer reliable evaluations of the brittleness of deep bedded sandstone in deep engineering practices,although further validation is necessary.

31.38 Gb/s GaN-based LED array visible light communication system enhanced with V-pit and sidewall quantum well structure

Although the 5G wireless network has made significant advances,it is not enough to accommodate the rapidly rising requirement for broader bandwidth in post-5G and 6G eras.As a result,emerging technologies in higher frequencies including visible light communication(VLC),are becoming a hot topic.In particular,LED-based VLC is foreseen as a key enabler for achieving data rates at the Tb/s level in indoor scenarios using multi-color LED arrays with wavelength division multiplexing(WDM)technology.This paper proposes an optimized multi-color LED array chip for high-speed VLC systems.Its long-wavelength GaN-based LED units are remarkably enhanced by V-pit structure in their efficiency,especially in the“yellow gap”region,and it achieves significant improvement in data rate compared with earlier research.This work investigates the V-pit structure and tries to provide insight by introducing a new equivalent circuit model,which provides an explanation of the simulation and experiment results.In the final test using a laboratory communication system,the data rates of eight channels from short to long wavelength are 3.91 Gb/s,3.77 Gb/s,3.67 Gb/s,4.40 Gb/s,3.78 Gb/s,3.18 Gb/s,4.31 Gb/s,and 4.35 Gb/s(31.38 Gb/s in total),with advanced digital signal processing(DSP)techniques including digital equalization technique and bit-power loading discrete multitone(DMT)modulation format.

小细胞肺癌分子分型研究进展

小细胞肺癌(small cell lung cancer,SCLC)是一种极具侵袭性和致命性的恶性肿瘤,具有病因复杂、分化程度低、恶性程度高、生长速度快、侵袭性强、转移早和获得性耐药等特点,导致患者的预后普遍较差。近年来,随着人们对SCLC发生发展分子机制研究的逐渐深入和多组学数据的深入挖掘,提出可以按照细胞内关键转录因子的差异表达进行分子分型,包括SCLC-A、SCLC-N、SCLC-P和SCLC-I等亚型。对SCLC进行分子分型研究并应用于临床,将有助于提高医生对SCLC患者的详细诊断和治疗方案的进一步优化,从而延长患者生存时间,提高患者生活质量。

Studying the performance of fully encapsulated rock bolts with modified structural elements

Numerical simulation is a useful tool in investigating the loading performance of rock bolts.The cable structural elements(cableSELs)in FLAC3D are commonly adopted to simulate rock bolts to solve geotechnical issues.In this study,the bonding performance of the interface between the rock bolt and the grout material was simulated with a two-stage shearing coupling model.Furthermore,the FISH language was used to incorporate this two-stage shear coupling model into FLAC3D to modify the current cableSELs.Comparison was performed between numerical and experimental results to confirm that the numerical approach can properly simulate the loading performance of rock bolts.Based on the modified cableSELs,the influence of the bolt diameter on the performance of rock bolts and the shear stress propagation along the interface between the bolt and the grout were studied.The simulation results indicated that the load transfer capacity of rock bolts rose with the rock bolt diameter apparently.With the bolt diameter increasing,the performance of the rock bolting system was likely to change from the ductile behaviour to the brittle behaviour.Moreover,after the rock bolt was loaded,the position where the maximum shear stress occurred was variable.Specifically,with the continuous loading,it shifted from the rock bolt loaded end to the other end.

FSK Modulation Scheme for High-Speed Optical Transmission

In this paper, we describe the generation, detection, and performance of frequency-shift keying （FSK） for high-speed optical transmission and label switching. A non-return-to-zero （NRZ） FSK signal is generated by using two continuous-wave （CW） lasers, one Mach-Zehnder modulator （MZM）, and one Mach-Zehnder delay interferometer （MZDI）. An RZ-FSK signal is generated by cascading a dual-arm MZM, which is driven by a sinusoidal voltage at half the bit rate. Demodulation can be achieved on 1 bit rate through one MZDI or an array waveguide grating （AWG） demultiplexer with balanced detection. We perform numerical simulation on two types of frequency modulation schemes using MZM or PM, and we determine the effect of frequency tone spacing （FTS） on the generated FSK signal. In the proposed scheme, a novel frequency modulation format has transmission advantages compared with traditional modulation formats such as RZ and differential phase-shift keying （DPSK）, under varying dispersion management. The performance of an RZ-FSK signal in a 4 x 40 Gb/s WDM transmission system is discussed. We experiment on transparent wavelength conversion based on four-wave mixing （FWM） in a semiconductor optical amplifier （SOA） and in a highly nonlinear dispersion shifted fiber （HNDSF） for a 40 Gb/s RZ-FSK signal. The feasibility of all-optical signal processing of a high-speed RZ-FSK signal is confirmed. We also determine the receiver power penalty for the RZ-FSK signal after a 100 km standard single-mode fiber （SMF） transmission link with matching dispersion compensating fiber （DCF）, under the post-compensation management scheme. Because the frequency modulation format is orthogonal to intensity modulation and vector modulation （polarization shift keying）, it can be used in the context of the combined modulation format to decrease the data rate or enhance the symbol rate. It can also be used in orthogonal label-switching as the modulation format for the payload or the label. As an example, we propose a simple orthogonal optical label switching technique based on 40 Gb/s FSK payload and 2.5 Gb/s intensity modulated （IM） label.

Recent progress on high-speed optical transmission

The recently reported high spectral efficiency （SE） and high-baud-rate szgnal transmission are all Daseo on digital coherent optical communications and digital signal processing （DSP）. DSP simplifies the re- ception of advanced modulation formats and also enables the major electrical and optical impairments to be processed and compensated in the digital domain, at the transmitter or receiver side. In this paper, we summarize the research progress on high-speed signal generation and detection and also show the progress on DSP for high-speed signal detection. We also report the latest progress on multi-core and multi-mode multiplexing.

Tutorial on laser-based visible light communications[Invited]

Facing escalating demands for high-speed,large-bandwidth,and low-latency wireless data links,laser communication technology has emerged as a promising technology.While free-space optical communication conventionally utilizes nearinfrared light sources,there has been growing interest in exploring new spectral resources,including visible lasers.Recently,laser-based white light has been demonstrated in visible light communication(VLC),with a unique capability to seamlessly integrate with illumination and display systems.This review summarizes the key devices and system technologies in semiconductor-laser-based white light for VLC-related applications.The recent advances and many emerging applications in the evolution of lighting,display,and communication are discussed.

Low-cost,large-coverage,and high-flexibility coherent PON for next-generation access networks:advances,challenges,and prospects[Invited]

Increasing bandwidth requirements have posed significant challenges for traditional access networks.It is difficult for intensity modulation/direct detection to meet the power budget and flexibility requirements of the next-generation passive optical network(PON)at 100G and beyond considering the new requirements.This is driving researchers to develop novel optical access technologies.Low-cost,wide-coverage,and high-flexibility coherent PON is emerging as a strong contender in the competition.In this article,we will review technologies that reduce the complexity of coherent PON(CPON),enabling it to meet the commercial requirements.Also,advanced algorithms and architectures that can enhance system coverage and flexibility are also discussed.

Channel estimation-based time-frequency neural network for post-equalization in underwater visible light communication

This Letter proposes a post-equalizer for underwater visible light communication(UVLC) systems that combines channel estimation and joint time-frequency analysis, named channel-estimation-based bandpass variable-order time-frequency network(CBV-TFNet). By utilizing a bandpass variable-order loss function with communication prior knowledge, CBVTFNet enhances communication performance and training stability. It enables lightweight implementation and faster convergence through a channel estimation-based mask. The superior performance of the proposed equalization method over Volterra and deep neural network(DNN)-based methods has been studied experimentally. Using bit-power loading discrete multitone (DMT) modulation, the proposed method achieves a transmission bitrate of 4.956 Gbps through a 1.2 m underwater channel utilizing only 38.15% of real multiplication calculations compared to the DNN equalizer and achieving a bitrate gain of440 Mbps and a significantly larger dynamic range over the LMS-Volterra equalizer. Results highlight CBV-TFNet's potential for future post-equalization in UVLC systems.

Lens-free wavefront shaping method for a diffuse non-lineof-sight link in visible light communication

In this Letter,we propose and experimentally demonstrate a lens-free wavefront shaping method that utilizes synchronized signal block beam alignment and a genetic algorithm(SSBGA)for a diffuse non-line-of-sight(NLOS)visible light communication(VLC)system.The proposed method effectively controls the position and mobility of visible light beams by partitioning spatial light modulator pixels and manipulating beams to converge at distinct spatial positions,thereby enhancing wavefront shaping efficiency,which achieves a significant 23.9 dB optical power enhancement at+2 mm offset,surpassing the lens-based continuous sequence(CS)scheme by 21.7 dB.At+40°angle,the improvement reaches up to 11.8 dB and 16.8 dB compared to the results with and without lens-based CS,respectively.A maximum rate of 5.16 Gbps is successfully achieved using bit-power loading discrete multi-tone(DMT)modulation and the proposed SSBGA in an NLOS VLC system,which outperforms the lens-based CS by 1.07 Gbps and obtains a power saving of 55.6%during the transmission at4 Gbps.To the best of our knowledge,this is the first time that high-speed communication has been realized in an NLOS VLC system without a lens.

Flexible 2 × 2 multiple access visible light communication system based on an integrated parallel GaN/InGaN micro-photodetector array module

In recent studies, visible light communication(VLC) has been predicted to be a prospective technique in the future 6G communication systems. To suit the trend of exponentially growing connectivity, researchers have intensively studied techniques that enable multiple access(MA) in VLC systems, such as the MIMO system based on LED devices to support potential applications in the Internet of Things(IoT) or edge computing in the nextgeneration access network. However, their transmission rate is limited due to the intrinsic bandwidth of LED.Unfortunately, the majority of visible light laser communication (VLLC) research with beyond 10 Gb/s data rates concentrates on point-to-point links, or using discrete photodetector(PD) devices instead of an integrated array PD. In this paper, we demonstrated an integrated PD array device fabricated with a Si-substrated GaN/InGaN multiple-quantum-well(MQW) structure, which has a 4 × 4 array of 50 μm × 50 μm micro-PD units with a common cathode and anode. This single-integrated array successfully provides access for two different transmitters simultaneously in the experiment, implementing a 2 × 2 MIMO-VLLC link at 405 nm. The highest data rate achieved is 13.2 Gb/s, and the corresponding net data rate(NDR) achieved is 12.27 Gb/s after deducing the FEC overhead, using 2.2 GHz bandwidth and superposed PAM signals. Furthermore, we assess the Huffman-coded coding scheme, which brings a fine-grain adjustment in access capacity and enhances the overall data throughput when the user signal power varies drastically due to distance, weather, or other challenges in the channel condition. As far as we know, this is the first demonstration of multiple visible light laser source access based on a single integrated GaN/InGaN receiver module.

High-speed GaN-based laser diode with modulation bandwidth exceeding 5 GHz for 20 Gbps visible light communication

Visible light communication(VLC)based on laser diodes demonstrates great potential for high data rate maritime,terrestrial,and aerial wireless data links.Here,we design and fabricate high-speed blue laser diodes(LDs)grown on c-plane gallium nitride(GaN)substrate.This was achieved through active region design and miniaturization toward a narrow ridge waveguide,short cavity length,and single longitudinal mode Fabry–Perot laser diode.The fabricated mini-LD has a low threshold current of 31 mA and slope efficiency of 1.02 W/A.A record modulation bandwidth of 5.9 GHz(−3dB)was measured from the mini-LD.Using the developed mini-LD as a transmitter,the VLC link exhibits a high data transmission rate of 20.06 Gbps adopting the bit and power loading discrete multitone(DMT)modulation technique.The corresponding bit error rate is 0.003,satisfying the forward error correction standard.The demonstrated GaN-based mini-LD has significantly enhanced data transmission rates,paving the path for energy-efficient VLC systems and integrated photonics in the visible regime.

Geochemical behavior of lithium isotopes in a small mountainous river of the Tibetan Plateau:A case study from Niyang River

Lithium(L_(i))and its isotopes are potential tracers of silicate weathering in river basins.However,the relationship between the Li isotopic composition(δ~7Li)in rivers and silicate weathering intensity remains unclear.This study analyzed the Li concentration and isotopic composition in river waters from the Niyang River,southern Tibetan Plateau.The results show that these samples have significantly variable Li concentrations(0.31–7.4μg/L)andδ~7Li values(+7.0–+20.7‰,n=28),and highδ~7Li values are found in several tributaries.Calculations indicate that dissolved Li in river water is predominantly derived from silicate weathering and geothermal water.With the exception of certain tributaries,geothermal water contributes 68%to 85%of the dissolved Li.Geothermal waters have lowδ~7Li values(-0.9–+2.9‰)in the Tibetan Plateau.Differences in the proportional contribution of dissolved Li in river samples from silicate weathering and geothermal water may be the main reason for the spatiotemporal variation in riverineδ~7Li values.The samples have higherδ~7Li values when the dissolved Li in the water samples is mainly derived from silicate weathering contributions,and lower values when the contribution from geothermal waters is high.Furthermore,the interaction of dissolved Li from geothermal water with secondary minerals results in Li isotopic fractionation,which may contribute to variations in river waterδ~7Li.It is accepted that the lower weathering intensity in orogenic(or mountainous)belts compared to floodplains is the main controlling factor for lowerδ~7Li values in the rivers.This study indicates that geothermal water input may cover the Li isotope signal of silicate weathering in river water,which in turn,affects the accurate understanding of the relationship between riverineδ~7Li values and the silicate weathering intensity.Therefore,whether the lowerδ~7Li values of river waters in hydrothermal-rich orogenic belts are mainly controlled by the regional weathering intensity or the input of hot springs(or both)requires in-depth study,and this is the key to accurately establishing the relationship between the Li isotopic composition and silicate weathering intensity in the river basin.

Si-substrate vertical-structure InGaN/GaN micro-LED-based photodetector for beyond 10 Gbps visible light communication

Visible light communication(VLC)has emerged as a promising communication method in 6G.However,the development of receiving devices is much slower than that of transmitting devices,limited by materials,structures,and fabrication.In this paper,we propose and fabricate an InGaN/GaN multiple-quantum-well-based vertical-structure micro-LED-based photodetector(μPD)on a Si substrate.A comprehensive comparison of the photoelectrical performance and communication performance of three sizes ofμPDs,10,50,and 100μm,is presented.The peak responsivity of all threeμPDs is achieved at 400 nm,while the passband full-widths at half maxima are 87,72,and 78 nm for 10,50,and 100μmμPDs,respectively.The−20 dB cutoff bandwidth is up to 822 MHz for 50μmμPD.A data rate of 10.14 Gbps is experimentally demonstrated by bit and power loading discrete multitone modulation and the proposed digital pre-equalizer algorithm over 1 m free space utilizing the self-designed 4×450μmμPD array as a receiver and a 450 nm laser diode as a transmitter.This is the first time a more than 10 Gbps VLC system has been achieved utilizing a GaN-based micro-PD,to the best of our knowledge.The investigation fully demonstrates the superiority of Si substrates and vertical structures in InGaN/GaNμPDs and shows its great potential for high-speed VLC links beyond 10 Gbps.

Role of EGFL7/EGFR-signaling pathway in migration and invasion of growth hormone-producing pituitary adenomas

Currently, the primary therapeutic strategy for most growth hormone-producing pituitary adenomas （GHPA） is surgery. Due to the invasiveness of GHPA, high recurrence has limited the benefit of complete adenoma removal surgery. Epidermal growth factor-like domain 7 （EGFL7） is a secreted factor implicated in tumor angiogenesis, growth, invasiveness and metastasis in GHPA. Herein, we observed that the expression level of EGFL7 and p-EGFR in invasive GHPA was much higher than that ofnon-invasive GHPA. The overexpression of EGFL7 was positively correlated with activation of EGFR （p-EGFR）. Noticeably, EGFL7 knockdown sig- nificantly inhibited activation of EGFR signaling cascades, including p-ERGR, p-AKT and p-ERK. Further studies showed that EGFL7 knockdown or pharmacological inhibition of EGFR-pathway, using EGFR inhibitor Tyrphostin AG-1478, significantly suppressed migration and invasion of GH3 and GTI-1 cells. In summary, our findings suggest that EGFL7 is a key factor for regulation of EGFR signaling pathway and plays an important role in migration and invasion of invasive GHPA.

Si-substrate LEDs with multiple superlattice interlayers for beyond 24 Gbps visible light communication

High-speed visible light communication(VLC)using light-emitting diodes(LEDs)is a potential complementary technology for beyond-5 G wireless communication networks.The speed of VLC systems significantly depends on the quality of LEDs,and thus various novel LEDs with enhanced VLC performance increasingly emerge.Among them,In Ga N/Ga N-based LEDs on a Si-substrate are a promising LED transmitter that has enabled VLC data rates beyond 10 Gbps.The optimization on the period number of superlattice interlayer(SL),which is a stressrelief epitaxial layer in a Si-substrate LED,has been demonstrated to be an effective method to improve Si-substrate LED’s luminescence properties.However,this method to improve LED’s VLC properties is barely investigated.Hence,we for the first time experimentally studied the impact of SL period number on VLC performance.Accordingly,we designed and fabricated an integrated 4×4 multichromatic Si-substrate wavelength-divisionmultiplexing LED array chip with optimal SL period number.This chip allows up to 24.25 Gbps/1.2 m VLC transmission using eight wavelengths,which is the highest VLC data rate for an In Ga N/Ga N LED-based VLC system to the best of our knowledge.Additionally,a record-breaking data rate of 2.02 Gbps over a 20-m VLC link is achieved using a blue Si-substrate LED with the optimal SL period number.These results validate the effectiveness of Si-substrate LEDs for both high-speed and long-distance VLC and pave the way for Si-substrate LED design specially for high-speed VLC applications.

240 Gb/s optical transmission based on an ultrafast silicon microring modulator

An ultrafast microring modulator(MRM) is fabricated and presented with V_(π)· L of 0.825 V · cm. A 240 Gb/s PAM-8 signal transmission over 2 km standard single-mode fiber(SSMF) is experimentally demonstrated. PN junction doping concentration is optimized, and the overall performance of the MRM is improved. Optical peaking is introduced to further extend the EO bandwidth from 52 to 110 GHz by detuning the input wavelength. A titanium nitride heater with 0.1 nm/m W tuning efficiency is implemented above the MRM to adjust the resonant wavelength. High bit rate modulations based on the high-performance and compact MRM are carried out. By adopting off-line signal processing in the transmitter and receiver side, 120 Gb/s NRZ, 220 Gb/s PAM-4, and240 Gb/s PAM-8 are measured with the back-to-back bit error ratio(BER) of 5.5 × 10^(-4), 1.5 × 10^(-2), and 1.4 × 10^(-2), respectively. A BER with different received optical power and 2 km SSMF transmission is also investigated. The BER for 220 Gb/s PAM-4 and 240 Gb/s PAM-8 after 2 km SSMF transmission is calculated to be 1.7 × 10^(-2), and 1.5 × 10^(-2), which meet with the threshold of soft-decision forward-error correction,respectively.

Ran binding protein 9(RanBPM) binds IFN-λR1 in the IFN-λsignaling pathway

Like the type I interferons(IFNs),the recently discovered cytokine IFN-λ displays antiviral,antiproliferative,and proapoptotic activities,mediated by a heterodimeric IFN-λ receptor complex composed of a unique IFN-λR1 chain and the IL-10R2 chain.However,the molecular mechanism of the IFN-λ-regulated pathway remains unclear.In this study,we newly identified RAN-binding protein M(RanBPM) as a binding partner of IFN-λR1.The interaction between RanBPM and IFN-λRl was identified with a glutathione S-transferase pull-down assay and coimmunoprecipitation experiments.IFN-λ1 stimulates this interaction and affects the cellular distribution of RanBPM.However,the interaction between RanBPM and IFN-λR1 does not correlate with their conserved TRAF6-binding sites.Furthermore,we also found that RanBPM is a scaffolding protein with a modulatory function that regulates the activities of IFN-stimulated response elements.Therefore,RanBPM plays a novel role in the IFN-λ-regulated signaling pathway.