A water-free, multi-wavelength diode-pumped Nd:YAG laser is demonstrated to yield a maximum output energy of 131 mJ at a pulse repetition frequency of 100 Hz and with pulse width of 9.6 ns. Zemax simulations informed the selection of a 0.8 at.% doping concentration in Nd:YAG crystals, which promoted a near-Gaussian gain profile. Thermal management was optimized through thermal insulation between the crystals and LDAs, combined with thermoelectric coolers (TECs), heat sinks for precise crystal temperature stabilization, and forced-air cooling for the LDAs. An electro-optic Q-switch based on deuterated potassium dihydrogen phosphate (DKDP) enabled stable pulse generation. The system operated reliably at repetition rates of 50-100 Hz, delivering up to 169.5 mJ per pulse at 80 Hz with pulse width ~8.8 ns and 131 mJ at pulse repetition of 100 Hz with pulse width of ~9.6 ns. The energy fluctuations of the RMS are better than 2.2%. Beam quality factors were measured as Mₓ² = 2.61 and Mᵧ² = 3.31. As far as we know, this is the first demonstration using multi-wavelength laser diode arrays as the pump source to achieve >100 mJ single-pulse energy and >10 MW peak power at a pulse repetition of 100 Hz under water-free cooling, while maintaining good beam quality.

为了降低光通信网络路由转发时的硬件成本和功耗，本文提出了一种灵活相干光接收机，采用了一套可用于硬件实现的低复杂度的数字信号处理(DSP)算法，可以在计算机控制下实现对15GBaud速率单极化QPSK和16QAM两种调制格式信号的处理。本文在仿真系统中对该数字信号处理方案进行了验证，并探索了其在不同信噪比下处理QPSK和16QAM信号的误码率性能。研究结果显示，以1e-3为FEC门限时，对于QPSK信号，当信噪比低于8.2时误码率超过FEC门限;对于16QAM信号，当信噪比低于15.5时误码率超过FEC门限。

With the increase of the demand for UHD HDR TV programs, more and more occasions require simul-production of UHD HDR and HD SDR. This paper introduces the methods and practical experience of simul-production and simulcast in CMG (China Media Group) for both recorded programs and live broadcast programs.

In this paper, we design a novel orthogonal time frequency space modulation based differential chaos shift keying (OTFS-DCSK) transceiver for reliable information transmissions. In this design, we exploit the orthogonal time frequency space (OTFS) modulation which is a two-dimensional modulation designed in the delay-Doppler domain, to combat multiplicative channel fading. Besides, since the OTFS-DCSK signal matrix is rank-1, we propose to utilize a singular vector decomposition (SVD) aided detection at the receiver to suppress the additive white Gaussian noise (AWGN) to further enhance the reliability. Thanks to the diversity obtained from OTFS modulation and the noise-suppression achieved by the SVD aided detection, the proposed OTFS-DCSK transceiver significantly improves the reliability performance, particular in the high-mobility wireless communications over the dual-dispersive channels caused by multipath propagation effects and Doppler shift effects. Simulation results validate the proposed OTFS-DCSK system outperforms the benchmark systems over AWGN, multipath and dual-dispersive fading channels.

Tunable 2∼3-μm femtosecond lasers are of high interest in various applications, such as medical diagnostics and molecular spectroscopy. Cr:ZnSe/ZnS is extremely suited for broadband tunable femtosecond lasers due to its excellent emission bands. In this article, we demonstrate a wavelength-tunable Kerr-lens mode-locked Cr:ZnS laser by utilizing a birefringent filter. The group delay dispersion of the operation and the thickness of the birefringent are finely optimized. With the rotation of the birefringent filter, the scheme offers a tuning bandwidth of over 300 nm from 2,220 nm to 2,520 nm. To the best of our knowledge, it is the broadest tuning range among the reported femtosecond Cr:ZnS lasers.

The high-frequency measurement of downhole vibration signal is vital for the analyses of abnormal vibration signal in the process of drilling. In this work, an acquisition method of downhole vibration high-frequency measurement signal based on compressed sensing technology is proposed. Moreover, the establishment method of sparse dictionary and observation matrix is studied in-depth, and an OMP algorithm against spectrum leakage is proposed. The performance of the proposed method has been investigated via simulations by varying the applied signals over 100 times. The result demonstrated that the proposed approach captures the high-frequency signal at the equivalent sampling rate of 390 MS/s by utilizing a low-speed ADCs with a sampling rate of 65 MS/s and a pseudo random binary sequence. This method provides a new way to acquire the high-frequency measurement data of downhole vibration, and provides favorable data support for mastering the comprehensive law of downhole vibration and diagnosing downhole abnormal vibration.

Great progress has been made in the generation of ultrashort laser pulses in the mid-infrared (MIR) band of femtosecond laser by intra-pulse difference frequency technology, and it has been widely used in physics, chemistry, biomedicine, and other scientific areas. Firstly, the development and research background of MIR laser are introduced. Then the basic principle of intra-pulse difference frequency generation (DFG) of femtosecond laser is introduced. The progress on MIR pulse generation by intra-pulse DFG with different driving sources, such as Ti: sapphire laser, femtosecond laser at 1 mu m waveband, femtosecond laser at 2 mu m waveband, and fiber laser, is reviewed and compared. Finally, the future developments of the MIR femtosecond laser generated by intra-pulse DFG are prospected.

With the rapid development and wide application of Internet of things, this article provides a modern scientific monitoring way for the application of radioactive sources and combines deeply with nuclear detection technology at present. By this way to form an Internet of things system for monitoring radioactive sources as the main part of the dangerous goods, it protects the healthy development of nuclear technology.

A resonantly pumped injection-seeded single-frequency Q-switched Ho:YAG ceramic laser is demonstrated. The seed laser is a single frequency Ho:YAG non-planar ring oscillator at 2090 nm. The slave laser is a Ho:YAG ceramic laser with a U-shape cavity. Single frequency Q-switched laser with output energy of 8.5 mJ, pulse duration of 94 ns and repetition rate of 200 Hz were obtained at 2090nm.

We demonstrated a 2097 nm Ho:YAG ceramic master oscillator and power amplifier system pumped by Tm:YLF lasers. Laser characteristics of 0.6 at.% and 0.4 at.% Ho:YAG ceramics were studied in CW and Q-switched modes. An output energy of 20.6 mJ at a pulse repetition frequency of 200 Hz was achieved from the master oscillator. The pulse energy was amplified to 34 mJ by the Ho:YAG ceramic amplifier with a pulse duration of 54 ns.

An injection-seeded Q-switched Ho: YAG laser at 2090 nm was demonstrated. Single-frequency laser pulses with energy of 17.04 mJ, and pulse duration of 122 ns at repetition rate of 250 Hz were obtained.

The successive sampling instead of periodic sampling for the vibration signal in the fatigue life test of rolling bearings is beneficial to the diagnosis of premature fatigue failure of bearings.The hardware design and software imple-mentation of the continuous data acquisition card in life test are presented.All the signal inputs/outputs,adjustment of rotating speed and loading during the test are completed on the acquisition card,the host can use relatively more time for online identification of premature fatigue failure of bearings.

Ovarian endometrioma is a common form of endometriosis, which may cause infertility, dysmenorrhea and pelvic pain in women of reproductive age. Although surgery is the treatment of choice for endometriomas, recurrence poses a formidable frustration. This study investigated potential risk factors of endometriomas recurrence, aiming to better understand its pathogenesis. A total of 307 patients with endometriomas were followed up for an average of 28.6 months and the 1-, 2- and 3-year cumulative recurrence rate was 9.5%, 21.9%, and 29.2%, respectively. Twenty-one potential risk factors for endometriomas recurrence were evaluated using Cox’s proportional hazards models. Total revised American Fertility Society（rAFS） score was significantly associated with higher recurrence（OR=1.858, 95% CI=1.122–3.075, P=0.016）, as well as younger age at surgery（OR=0.953, 95% CI=0.915–0.992, P=0.020）. Semiradical surgical treatment was defined as surgical removal of cyst plus hysterectomy with preservation of bilateral or unilateral ovary, and was a significant factor that was associated with lower recurrence than the conservative surgery（OR=0.318, 95% CI=0.107–0.951, P=0.040）. Postoperative pregnancy was favorable factors for disease recurrence（OR=0.217, 95% CI=0.102–0.460, P=0.000）. The results suggest that endometrioma recurrence is inversely associated with age at surgery and postoperative pregnancy, and may correlate with total rAFS score and conservative surgery method.

通过对国内外辐射环境剂量监测现状的分析,结合我国核技术应用的现状以及黑龙江省所处的地理位置,提出黑龙江省辐射环境剂量监测网络建设的构想,对加快智慧型城市建设和构建和谐社会具有重要的意义.

We demonstrated a Q-switched Ho:YAG ceramic laser operating at 2097 nm. The Ho:YAG ceramic laser was resonantly pumped by a Tm:YLF laser at 1908 nm. The laser performance with two Ho-doping concentrations of Ho:YAG ceramics in a U-shaped resonator was studied. Different pump spots were investigated to obtain high extract efficiency. The wavelength of Ho:YAG ceramic laser was tuned from 2090.70 nm to 2098.10 nm. The Q-switched pulse energy were 9.6 mJ at a pulse repetition frequency (PRF) of 200 Hz and 10.2 mJ at a PRF of 100 Hz, respectively. The beam quality M(2) factors were measured to be less than 1.1 in both directions.

A wavelength-space tunable dual-wavelength fiber laser for millimeter wave signal processing is demonstrated based on an Opto-DMD and the PCF. The wavelength spacing can be experimentally tuned from ~20 GHz to ~135 GHz.

A resonantly pumped monolithic Ho:YAG nonplanar ring oscillator (NPRO) with single-frequency and dual-wavelength laser outputs is demonstrated. The Ho:YAG NPRO is resonantly pumped by a 1907-nm Tm:YLF laser. In single-frequency operation, the output power is 3.09 W, with a slope efficiency of 61% and an optical efficiency of 48% with respect to the pump power. Up to 10 W dual-wavelength laser output at 2091 and 2097 nm is also obtained from the Ho:YAG NPRO with the maximum pump power, with a slope efficiency of 61% with respect to the pump power. (C) 2014 Society of Photo-Optical Instrumentation Engineers (SPIE)

We demonstrated a stable single-frequency laser operating at 2122 nm from a monolithic nonplanar Ho:YAG ring oscillator (NPRO). The Ho:YAG NPRO was resonantly pumped by a 1907 nm Tm:YLF laser built up by ourselves. The maximum multimode output power from the Ho:YAG NPRO was 9.66 W and the slope efficiency was 71.7%. With accurate adjustment of the pump position to make the laser oscillate in single frequency condition, an output power of 8.0 W was obtained with a slope efficiency of 61.4% and an optical-optical efficiency of 50.0%. The power stability of the Ho:YAG NPRO laser was 0.29% at maximum single frequency output power. The beam quality M(2) factors were measured to be less than 1.1 in x- and y- directions.

Traditional GM counter and scintillation detector was substituted by high-pressure chamber,in order to improve the measurement sensitivity and obtain better energy response. The pA level current signal,output from high-pressure spherical chamber,was amplified with low input offset current electrometer amplifier. Therefore,the radiation dose monitoring equipment with high accuracy,wide range and well stable and reliable operation was designed and produced.

Mn-Co-Ni-O system semiconductor ceramic is the most common infrared thermistor material, but it has a weak bonding strength with the conventional Au electrode. In this paper, the Ti/Au double layer electrode was used as electrode of semiconductor ceramic wafer, and the effects of Ti/Au electrode on interfacial bonding strength and noise factor were investigated. It is found that the Ti/Au electrode has a good bonding strength with the semiconductor ceramic wafer, and the thermistor has relative low noise factor. The influence mechanism of Ti/Au electrode on noise factor is due to the titanium oxide, which is formed by Ti element diffusion through Au layer and reaction with oxygen. During the heat treatment, the Ti layer reacts with the wafer substrate, in the meantime, the Ti element diffuses through the Au layer. Elevating the heat treatment temperature, increasing the thickness of Au layer or decreasing the thickness of Ti layer can inhibit the diffusion of Ti element to the Au surface, and the noise factor is declined consequently.