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Pingxiang Xiangdong shadow play, as the national traditional intangible cultural heritage, has a long history and rich forms of expression, but in the wave of the new era, confined to the geographical and human factors, lack of development opportunities, transferred between the township, the urgent need for inheritance and development. The combination of game and traditional culture is the trend and trend, and the appropriate innovation of traditional cultural presentation should adapt to the trend of the times, cater to the development needs of the society, and make appropriate adjustment from itself, according to its own development law proactively. As a national traditional intangible cultural heritage with profound historical foundation, Pingxiang Xiangdong shadow play should innovate and change the way of promotion as soon as possible, and seek new development in the new era by taking the new industry such as games as the medium, and drive the construction of the region, accelerate the construction of regional special cultural industry and develop regional special culture.

This work reports a $\beta $ -Ga2O3 double-barrier Schottky barrier diode (DBSBD) with both low turn-on voltage and low reverse leakage current by using Ni and PtOx as the anode electrode. The barrier height of PtOx-based diode can be effectively modulated from 1.26 to 1.62 eV by adjusting oxygen pressure during sputtering processes. Combining the maximum work function of PtOx electrode with the optimization of the electrode ratio of Ni and PtOx, the DBSBD with an electrode diameter ratio of $\text{D}_{\text {Ni}} /\text{D}_{\text {PtOx}}= {75}/{150} \mu \text{m}$ not only exhibits a high forward current of 470.9 A/cm2 (at 3.5 V), a low on-resistance of 4.1 $\text{m}\Omega ~\cdot $ cm2 and a low turn-on voltage of 1.13 V, but also possesses a relatively low reverse leakage current of ${1.2}\times {10}^{-{7}}$ A/cm2 (at −100 V), which is more than one order of magnitude lower than that of the Ni-SBD. Silvaco TCAD simulation reveals that such optimization can be attributed to the suppression of edge leakage current due to the double-barrier contact. Therefore, the strategy of double-barrier design can balance the forward and reverse characteristics in SBD, providing a new device structure for advanced power electronics.

Background: Abdominal aortic aneurysm (AAA) is a severe aortic disease with a high mortality rate in the event of rupture. Pharmacological therapy is needed to inhibit AAA expansion and prevent aneurysm rupture. Transcription factor EB (TFEB), a master regulator of autophagy and lysosome biogenesis, is critical to maintain cell homeostasis. In this study, we aim to investigate the role of vascular smooth muscle cell (VSMC) TFEB in the development of AAA and establish TFEB as a novel target to treat AAA. Methods: The expression of TFEB was measured in human and mouse aortic aneurysm samples. We used loss/gain-of-function approaches to understand the role of TFEB in VSMC survival and explored the underlying mechanisms through transcriptome and functional studies. Using VSMC-selective Tfeb knockout mice and different mouse AAA models, we determined the role of VSMC TFEB and a TFEB activator in AAA in vivo. Results: We found that TFEB is downregulated in both human and mouse aortic aneurysm lesions. TFEB potently inhibits apoptosis in VSMCs, and transcriptome analysis revealed that TFEB regulates apoptotic signaling pathways, especially apoptosis inhibitor B-cell lymphoma 2. B-cell lymphoma 2 is significantly upregulated by TFEB and is required for TFEB to inhibit VSMC apoptosis. We consistently observed that TFEB deficiency increases VSMC apoptosis and promotes AAA formation in different mouse AAA models. Furthermore, we demonstrated that 2-hydroxypropyl-β-cyclodextrin, a clinical agent used to enhance the solubility of drugs, activates TFEB and inhibits AAA formation and progression in mice. Last, we found that 2-hydroxypropyl-β-cyclodextrin inhibits AAA in a VSMC TFEB–dependent manner in mouse models. Conclusions: Our study demonstrated that TFEB protects against VSMC apoptosis and AAA. TFEB activation by 2-hydroxypropyl-β-cyclodextrin may be a promising therapeutic strategy for the prevention and treatment of AAA.

PURPOSE: Abdominal aortic aneurysm (AAA) is one of the leading causes of death in the developed world and is currently undertreated due to the complicated nature of the disease. Herein, we aimed to address the therapeutic potential of a novel class of pleiotropic mediators, specifically a new drug candidate, nitro-oleic acid (NO(2)-OA), on AAA, in a well-characterized murine AAA model. METHODS: We generated AAA using a mouse model combining AAV.PCSK9-D377Y induced hypercholesterolemia with Angiotensin II given by chronic infusion. Vehicle control (PEG-400), oleic acid (OA), or NO(2)-OA were subcutaneously delivered to mice using osmotic minipump. We characterized the effects of NO(2)-OA on pathophysiological responses and dissected the underlying molecular mechanisms through various in vitro and ex vivo strategies. RESULTS: Subcutaneous administration of NO(2)-OA significantly decreased the AAA incidence (8/28 mice) and supra-renal aorta diameters as compared to mice infused with either PEG-400 (13/19, p=0.0117) or OA (16/23, p=0.0078). In parallel, the infusion of NO(2)-OA in the AAA model drastically decreased extracellular matrix degradation, inflammatory cytokine levels, and leucocyte/macrophage infiltration in the vasculature. Administration of NO(2)-OA reduced inflammation, cytokine secretion, and cell migration triggered by various biological stimuli in primary and macrophage cell lines partially through activation of the peroxisome proliferator-activated receptor-gamma (PPARγ). Moreover, the protective effect of NO(2)-OA relies on the inhibition of macrophage prostaglandin E2 (PGE(2))-induced PGE(2) receptor 4 (EP4) cAMP signaling, known to participate in the development of AAA. CONCLUSION: Administration of NO(2)-OA protects against AAA formation and multifactorial macrophage activation. With NO(2)-OA currently undergoing FDA approved Phase II clinical trials, these findings may expedite the use of this nitro-fatty acid for AAA therapy.

GTPase-activating SH3 domain-binding protein 2 (G3BP2) is a mediator that responds to environmental stresses through stress granule formation and is involved in the progression of chronic diseases. However, no studies have examined the contribution of G3BP2 in the oscillatory shear stress (OSS)-induced endothelial dysfunction. Here we assessed the effects of G3BP2 in endothelial cells (ECs) function and investigated the underlying mechanism. Using shear stress apparatus and partial ligation model, we identified that stress granule-related genes in ECs could be induced by OSS with RNA-seq, and then confirmed that G3BP2 was highly and specifically expressed in athero-susceptible endothelia in the OSS regions. G3bp2–/–Apoe–/– mice had significantly decreased atherosclerotic lesions associated with deficiency of G3BP2 in protecting endothelial barrier function, decreasing monocyte adhesion to ECs and inhibiting the proinflammatory cytokine levels. Furthermore, loss of G3BP2 diminished OSS-induced inflammation in ECs by increasing YAP nucleocytoplasmic shuttling and phosphorylation. These data demonstrate that G3BP2 is a critical OSS regulated gene in regulating ECs function and that G3BP2 inhibition in ECs is a promising atheroprotective therapeutic strategy.

In this letter, trench-gate metal–oxide–semiconductor field-effect transistors on (010) $\beta $ -Ga2O3 epitaxial layer are fabricated. Enhancement mode is achieved by the gate-recess process, through thoroughly depleting the $\beta $ -Ga2O3 channel to get a positive threshold voltage. For the first time, by using a dynamic parameter test system, the Ga2O3 MOSFET with 2- $\mu \text{m}$ gate length is characterized to present short switching time, including turn-on time ( $\textit {t}_{ \mathrm{\scriptscriptstyle ON}}$ ) of 28.6 ns and turn-off time ( $\textit {t}_{ \mathrm{\scriptscriptstyle OFF}}$ ) of 94.0 ns. In addition, OFF-state interelectrode parasitic capacitances, including input capacitance ( $\textit {C}_{\text {iss}}$ ) of 37 pF/mm, output capacitance ( $\textit {C}_{\text {oss}}$ ) of 42 pF/mm, and reverse transfer capacitance ( $\textit {C}_{\text {rss}}$ ) of 14 pF/mm are also obtained, which can account for the high switching speed. The static and dynamic switching properties of the trench-gate device show the potential of $\beta $ -Ga2O3 MOSFET for the high-speed switching applications.

The unmanned surface vehicles (USV) are required to perform a dynamic obstacle avoidance during fulfilling a task. This is essential for USV safety in case of an emergency and such action has been proved to be difficult. However, little research has been done in this area. This study proposes an emergency collision avoidance algorithm for unmanned surface vehicles (USVs) based on a motion ability database. The algorithm is aimed to address the inconsistency of the existing algorithm. It is proposed to avoid collision in emergency situations by sharp turning and treating the collision avoidance process as a part of the turning movement of USV. In addition, the rolling safety and effect of speed reduction during the collision avoidance process are considered. First, a USV motion ability database is established by numerical simulation. The database includes maximum rolling angle, velocity vector, position scalar, and steering time data during the turning process. In emergency collision avoidance planning, the expected steering angle is obtained based on the International Regulations for Preventing Collisions at Sea (COLREGs), and the solution space, with initial velocity and rudder angle taken as independent variables, is determined by combining the steering time and rolling angle data. On the basis of this solution space, the objective function is solved by the particle swarm optimization (PSO) algorithm, and the optimal initial velocity and rudder angle are obtained. The position data corresponding to this solution is the emergency collision avoidance trajectory. Then, the collision avoidance parameters were calculated based on the afore mentioned model of motion. With the use of MATLAB and Unity software, a semi-physical simulation platform was established to perform the avoidance simulation experiment under emergency situation. Results show the validity of the algorithm. Hence results of this research can be useful for performing intelligent collision avoidance operations of USV and other autonomous ships

To extract the time-series characteristics of the original bearing signals and predict the remaining useful life (RUL) more effectively, a parallel multichannel recurrent convolutional neural network (PMCRCNN) is proposed for the prediction of RUL. Firstly, the time domain, frequency domain, and time-frequency domain features are extracted from the original signal. Then, the PMCRCNN model is constructed. The front of the model is the parallel multichannel convolution unit to learn and integrate the global and local features from the time-series data. The back of the model is the recurrent convolution layer to model the temporal dependence relationship under different degradation features. Normalized life values are used as labels to train the prediction model. Finally, the RUL was predicted by the trained neural network. The proposed method is verified by full life tests of bearing. The comparison with the existing prognostics approaches of convolutional neural network (CNN) and the recurrent convolutional neural network (RCNN) models proves that the proposed method (PMCRCNN) is effective and superior in improving the accuracy of RUL prediction.

Objective: Currently, there are no approved drugs for abdominal aortic aneurysm (AAA) treatment, likely due to limited understanding of the primary molecular mechanisms underlying AAA development and progression. BAF60a—a unique subunit of the SWI/SNF (switch/sucrose nonfermentable) chromatin remodeling complex—is a novel regulator of metabolic homeostasis, yet little is known about its function in the vasculature and pathogenesis of AAA. In this study, we sought to investigate the role and underlying mechanisms of vascular smooth muscle cell (VSMC)–specific BAF60a in AAA formation. Approach and Results: BAF60a is upregulated in human and experimental murine AAA lesions. In vivo studies revealed that VSMC-specific knockout of BAF60a protected mice from both Ang II (angiotensin II)–induced and elastase-induced AAA formation with significant suppression of vascular inflammation, monocyte infiltration, and elastin fragmentation. Through RNA sequencing and pathway analysis, we found that the expression of inflammatory response genes in cultured human aortic smooth muscle cells was significantly downregulated by small interfering RNA–mediated BAF60a knockdown while upregulated upon adenovirus-mediated BAF60a overexpression. BAF60a regulates VSMC inflammation by recruiting BRG1 (Brahma-related gene-1)—a catalytic subunit of the SWI/SNF complex—to the promoter region of NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) target genes. Furthermore, loss of BAF60a in VSMCs prevented the upregulation of the proteolytic enzyme cysteine protease CTSS (cathepsin S), thus ameliorating ECM (extracellular matrix) degradation within the vascular wall in AAA. Conclusions: Our study demonstrated that BAF60a is required to recruit the SWI/SNF complex to facilitate the epigenetic regulation of VSMC inflammation, which may serve as a potential therapeutic target in preventing and treating AAA.

We report a high-power 10 ps level ultrashort pulsed polarization maintaining (PM) supercontinuum source (SCS) fiber amplifier based on a typical Master Oscillator Pulse Amplification (MOPA) configuration. At the pulse width of 12.1 ps, an average output power of 35.45 W is achieved with the single pulse energy of 2.2 μJ. The output wide spectrum ranging from 1020 nm to 1700 nm has been obtained directly from the Yb-doped fiber amplification (YDFA). But the nonlinear effects in this amplification system are too strong to enhance the average power due to the high peak power of 184 kW. Thus an improved high-power picosecond pulsed PM fiber amplifier is achieved based on a chirped pulse amplification (CPA) configuration. The pulse width is stretched to hundred picosecond scale to reduce the high nonlinear effects and the high peak power by a PM single mode fiber (SMF) stretcher. Only 0.9 m-long PM highly Yb-doped fiber is used in the main-stage amplifier. High average output power of 100.8 W is achieved with repetition rate of 16.68 MHz and pulse width of 280 ps. The central wavelength of the output laser is 1064 nm with 3 dB bandwidth of 2.32 nm. The peak power is 21.58 kW and the single pulse energy is 6.04 μJ, respectively. In addition, the pulse trains are stable without serious distortion and pulse splitting which ensure that the high power PM pulse laser can be used in both fundamental research and industrial fields.

In this paper, a 38.7 W amplified (24.8 W compressed) picosecond ytteribium-fiber chirped-pulse amplification system at 1030.3 nm is demonstrated using chirped-volume Bragg grating for the compressor and photonic crystal fiber for the spectral stretcher. For optimizing compressed pulse duration, the spectral width is fine-tuned by controlling the length, dispersion and the parameters of the nonlinear of the photonic crystal fiber, which is an additional dispersion compensation method to eliminate the residual dispersion in the chirped-pulse amplification system. As a result, the chirped pulse width of 330 ps is amplified in ytteribium-doped fiber amplifier and subsequently, re-compressed to 1.1 ps duration corresponding to the peak power of 1.1 MW.

Perivascular adipose tissue (PVAT), the adipose tissue that surrounds most of the vasculature, has emerged as an active component of the blood vessel wall regulating vascular homeostasis and affecting the pathogenesis of atherosclerosis. Although PVAT characteristics resemble both brown and white adipose tissues, recent evidence suggests that PVAT develops from its own distinct precursors implying a closer link between PVAT and vascular system. Under physiological conditions, PVAT has potent anti-atherogenic properties mediated by its ability to secrete various biologically active factors that induce non-shivering thermogenesis and metabolize fatty acids. In contrast, under pathological conditions (mainly obesity), PVAT becomes dysfunctional, loses its thermogenic capacity and secretes pro-inflammatory adipokines that induce endothelial dysfunction and infiltration of inflammatory cells, promoting atherosclerosis development. Since PVAT plays crucial roles in regulating key steps of atherosclerosis development, it may constitute a novel therapeutic target for the prevention and treatment of atherosclerosis. Here, we review the current literature regarding the roles of PVAT in the pathogenesis of atherosclerosis.

Background: The perivascular adipose tissue (PVAT) surrounding vessels constitutes a distinct functional integral layer of the vasculature required to preserve vascular tone under physiological conditions. However, there is little information on the relationship between PVAT and blood pressure regulation, including its potential contributions to circadian blood pressure variation. Methods: Using unique brown adipocyte–specific aryl hydrocarbon receptor nuclear translocator-like protein 1 (Bmal1) and angiotensinogen knockout mice, we determined the vasoactivity of homogenized PVAT in aortic rings and how brown adipocyte peripheral expression of Bmal1 and angiotensinogen in PVAT regulates the amplitude of diurnal change in blood pressure in mice. Results: We uncovered a peripheral clock in PVAT and demonstrated that loss of Bmal1 in PVAT reduces blood pressure in mice during the resting phase, leading to a superdipper phenotype. PVAT extracts from wild-type mice significantly induced contractility of isolated aortic rings in vitro in an endothelium-independent manner. This property was impaired in PVAT from brown adipocyte–selective Bmal1-deficient (BA-Bmal1-KO) mice. The PVAT contractile properties were mediated by local angiotensin II, operating through angiotensin II type 1 receptor–dependent signaling in the isolated vessels and linked to PVAT circadian regulation of angiotensinogen. Indeed, angiotensinogen mRNA and angiotensin II levels in PVAT of BA-Bmal1-KO mice were significantly reduced. Systemic infusion of angiotensin II, in turn, reduced Bmal1 expression in PVAT while eliminating the hypotensive phenotype during the resting phase in BA-Bmal1-KO mice. Angiotensinogen, highly expressed in PVAT, shows circadian expression in PVAT, and selective deletion of angiotensinogen in brown adipocytes recapitulates the phenotype of selective deletion of Bmal1 in brown adipocytes. Furthermore, angiotensinogen is a transcriptional target of Bmal1 in PVAT. Conclusions: These data indicate that local Bmal1 in PVAT regulates angiotensinogen expression and the ensuing increase in angiotensin II, which acts on smooth muscle cells in the vessel walls to regulate vasoactivity and blood pressure in a circadian fashion during the resting phase. These findings will contribute to a better understanding of the cardiovascular complications of circadian disorders, alterations in the circadian dipping phenotype, and cross-talk between systemic and peripheral regulation of blood pressure.

// Jian Yang 1, * , Jian-Nan Zhang 2, * , Wei-Lin Chen 1 , Gui-Song Wang 1 , Qing Mao 1 , Shan-Quan Li 2 , Wen-Hao Xiong 1 , Ying-Ying Lin 1 , Jian-Wei Ge 1 , Xiao-Xiong Li 1 , Zhao Gu 1 , Chun-Run Zhao 1 1 Department of Neurosurgery, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P. R. China 2 Operation Room, Shanghai Children’s Medical Center, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, P. R. China * These authors contributed equally to this work Correspondence to: Jian-Wei Ge, email: gejianweior@163.com Xiao-Xiong Li, email: lixiaoxiongzj@yeah.net Keywords: AQP5, U87-MG cells, U251 cells, LN229 cells, cell apoptosis Received: May 17, 2016 Accepted: January 06, 2017 Published: March 22, 2017 ABSTRACT We investigated the effects of aquaporin 5 ( AQP5 ) gene silencing on the proliferation, migration and apoptosis of human glioma cells through regulating the EGFR/ERK/p38MAPK signaling pathway. qRT-PCR was applied to examine the mRNA expressions of AQP5 in five human glioma cell lines. U87-MG, U251 and LN229 cells were selected and assigned into blank, vector, AQP5 siRNA and Flag AQP5 groups. MTT assay was used to measure cell proliferation. Flow cytometry (FCM) with AnnexinV-FITC/PI double staining and PI staining were employed to analyze cell apoptosis and cell cycle respectively. Scratch test was used to detect cell migration. Western blotting was performed to determine the EGFR/ERK/p38 MAPK signaling pathway-related proteins. Results showed that the positive expression of AQP5 in primary glioblastoma was associated with the tumor size and whether complete excision was performed. The mRNA expressions of AQP5 in cell lines of U87-MG, U251 and LN229 were significantly higher than in U373 and T98G. The proliferation rates of U87-MG, U251 and LN229 cells in the AQP5 siRNA group were lower than in the vector and blank groups. The apoptosis rate increased in the AQP5 siRNA group compared with the vector group. Scratch test demonstrated that AQP5 gene silencing could suppress cell migration. Compared with the vector and blank groups, the AQP5 siRNA group showed decreased expressions of the ERK1/2, p38 MAPK, p-ERK1/2 and p-p38 MAPK proteins. AQP5 gene silencing could inhibit the cell proliferation, reduce cell migration and promote the cell apoptosis of U87-MG, U251 and LN229 by suppressing EGFR/ERK/p38 MAPK signaling pathway.

Gypsum-based composite boards reinforced with mono- and multilayer perforated amorphous Fe78Si9B13 ribbons were fabricated by pouring gypsum slurry directly into molds with prelaid epoxy-re...

In many military and law-enforcement covert missions, wireless communication links need to remain undetected. In this paper, a novel spectrum spread technique based on noise modulated (NM) transmission is proposed and a feasibility study was conducted. In NM transmissions a reference pseudo-noise signal is generated and is superposed with the information signal, with a time delay. The pseudo-random noise sequence is transmitted separately and used to recover the signal from the noise modulated information signal. The transmitted information signal is noise like making it difficult to detect or decode by an adversary. If an adversary does discover the transmission, decoding is difficult without the pseudo-random noise sequence and time delay between noise and signal. Conventional NM uses polarized antennas to orthogonally transmit the noise modulated information signal and pseudo-noise signal. However, the two polarized antennas are rarely, if ever, completely isolated in practice making signal recovery difficult if not impossible. In this paper a feasibility study was performed on a novel multi-frequency NM scheme for NM communications with a single polarized antenna. A universal software radio peripheral (USRP) software defined radio (SDR) testbed was used to demonstrate that multi-frequency NM transmission masks a QPSK signal from an adversary and the signal can be successfully recovered by a friendly receiver.

Through simulation calculations and experiments, the two popular methods of generating nanosecond (ns) pulsed laser were studied respectively. A new method for generating a ns pulsed laser with high power and ultra-high repetition frequency by using dispersive fiber after SESAM mode-locked oscillator was proposed. In the simulation calculation of the mode-locked ns pulsed laser, the time-frequency evolution characteristics of the laser formation process were analyzed. The variation process of the stimulated Raman scattering (SRS) effect was obtained at different injection powers. In the simulation calculation of the extracavity modulation ns pulsed laser, the threshold of the stimulated Brillouin scattering (SBS) effect was obtained in the 4-stage fiber amplification experiment. Then, the nonlinear dynamics model of the ns pulsed fiber laser was established by considering various nonlinear effects. The results showed the theoretical models were consistent with the experimental investigations. This provided a new way to further optimize the parameter of ns pulsed fiber lasers and also contribute to solve nonlinear damage problems in such lasers.

We report on a nanosecond all-fiber MOPA with ultra-high repetition rate (tens of MHz), which is seeded by a semiconductor saturable absorber mirror (SESAM) mode-locking fiber oscillator at 1064 nm. Ultra-high repetition rate of tens of MHz is realized by reducing fiber length in laser cavity. By using single-mode fiber stretcher with total length of 16 km, pulse width of mode locking laser pulse can be broadened from 28 ps to 1~7 ns. The maximum average power is achieved to be 54 W with pulse duration of 1.3 ns and repetition rate of 27.7 MHz. To the best of our knowledge, this is the first demonstration on an ultra-high repetition-rate (tens of MHz) nanosecond all-fiber MOPA based on a SESAM passively mode-locking fiber oscillator.

Mobile ad-hoc networks (MANET) have been widely used in many different areas, such as mobile sensor networks, smart vehicle systems, unmanned aerial vehicle relayed networks, etc. In all scenarios, routing is one of the key technical challenges. In order to improve the quality of communication and extend the lifetime of all battery-powered units, we propose a novel routing algorithm that incorporates the concerns about battery level, quality of service (QoS), motion of nodes, and routing overhead. In addition to the routing algorithm, we also design a connection maintenance method that monitors the quality of the route during communication and determines the time to find a new route. Via numerical results, it is proven that our design has a good balance among the requirements of stability, delay, overhead, and network lifetime.

In this Letter, we report a high-performance NiO/β-Ga2O3 pn heterojunction diode with an optimized interface by annealing. The electrical characteristics of the pn diode without annealing (PND) and with annealing (APND) are studied systematically. The APND device has a lower specific on-resistance of 4.1 mΩ cm2, compared to that of the PND, 5.4 mΩ cm2. Moreover, for the APND, a high breakdown voltage of 1630 V with lower leakage current is achieved, which is 730 V higher than that of the PND. The enhanced electrical performance of the APND leads to a record high power figure of merit of 0.65 GW/cm2 in Ga2O3-based pn diodes, which is among the best reported results in Ga2O3 power devices. In addition, the interface trap density of the diode decreases from 1.04 × 1012 to 1.33 × 1011 eV−1 cm−2 after annealing, contributing to much lower hysteresis. Simultaneously, the ideality factor n for the APND is steady at elevated temperatures due to the stable interface. The results of C − V characteristics reveal the bulk defects inside the nickel oxide film grown by sputtering, which are calculated by high- and low-frequency capacitance methods. X-ray photoelectron spectroscopy of NiO illustrates the reasons for the changes in the concentration of holes and defects in the film before and after annealing. This work paves the way for further improving the performance of Ga2O3 diode via interface engineering.

We report a linear-cavity mode-locked Yb-doped fiber laser using self-made semiconductor saturable absorber mirrors (SESAMs). The SESAMs are grown by means of metalorganic chemical vapor deposition, with a design of high modulation depth using strain-compensated multiple quantum wells. We choose two kinds of self-made SESAMs with different periods of top reflector in the linear cavity, and they can both be applied to stable mode-locking operation without damage. The output characteristics of the mode-locked oscillator indicate that SESAMs with high modulation depth are beneficial for mode-locked fiber lasers and the modulation depth can limit the pulse width of the output pulses.

We report on a nanosecond all-fiber amplifier with repetition rate of tens of MHz. It is based on a passively mode-locked fiber oscillator at 1064 nm, which has a pulse width of 28 ps and repetition rate of 27.7 MHz. The single-mode fiber with length of 8 km is adopted as a fiber stretcher, in which new frequency components are introduced by strong nonlinear effect such as self-phase modulation, resulting in the broadening of spectral bandwidth from 0.4 nm to around 20 nm. The group-velocity dispersion of the 8 km fiber stretcher is −38 ps (nm km) −1, which stretches the pulse duration of the picosecond pulse to 1–7 ns. At the repetition rate of 27.7 MHz, an average power of 54 W is demonstrated with pulse width of 1.3 ns, and 21 W is achieved with pulse width of ∼5 ns, which have optical-to-optical conversion efficiencies of 41.2% and 30.1% respectively. This all-fiber amplifier based on the passively mode-locked fiber oscillator and 8 km single-mode fiber stretcher is capable of delivering nanosecond pulses while maintaining an ultra-high repetition rate of tens of MHz.

In this paper, we study user selection (US) strategies for a multiple-input–multiple-output (MIMO) cognitive radio (CR) downlink network, where the $r$ -antenna underlay CR secondary users (SUs) coexist with a primary user (PU), and all terminals are equipped with multiple antennas. Two main scenarios are considered: 1) The $t$ -antenna cognitive base station (CBS) has perfect or partial channel state information at the transmitter (CSIT) from the CBS to the PU receiver (RX), and 2) the CBS has absolutely no PU CSIT. For these scenarios, we propose and evaluate multiple SU selection schemes that are applicable to both best-effort PU interference mitigation and hard interference temperature (IT) constraints. The computational complexity of the proposed schemes can be significantly smaller than that of an exhaustive search with negligible performance degradation. For the selection of $C$ SUs out of $K$ candidates, our proposed sliding window scheme, for example, is of complexity $\mathcal{O}(Krt^2)$ , whereas an exhaustive search is on the order of $\mathcal{O}(\binom{K}{C}C^4r^3)$ . When $t$ and $r$ are of the same order, the computational complexity of the proposed scheme can be $\binom{K}{C}C^4/K$ times smaller. Mathematical complexity analysis and numerical simulations are provided to show the advantage of our schemes.

Power management is a critical component for wireless networks involving battery operated devices operating in harsh and unpredictable environments. This paper proposes the use of hybrid automatic repeat request (HARQ) for energy efficient power management that improves network reliability, guarantees quality of service (QoS), and extends network lifetime. A power optimization problem is first formulated under peak power, energy budget, causality (when energy harvesting is used), and QoS constraints. Relaxation of some of constraints is then proposed that is motivated by practical considerations as well as complexity issues. An efficient solution to the simplified optimization problem is then put forward to compute the optimal operating modes/parameters and an interpolation scheme is then proposed for real time implementation. Numerical results are then presented that demonstrate the effectiveness of the proposed design approach in achieving much lower energy consumption while guaranteeing the required communication QoS.