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In this paper, we analyze the neutrino-driven winds that emerge in twelve unprecedentedly long-duration 3D core-collapse supernova simulations done using the code Fornax. The twelve models cover progenitors with ZAMS mass between 9 and 60 solar masses. In all our models, we see transonic outflows that are at least two times as fast as the surrounding ejecta and that originate generically from a PNS surface atmosphere that is turbulent and rotating. We find that winds are common features of 3D simulations, even if there is anisotropic early fallback. We find that the basic dynamical properties of 3D winds behave qualitatively similarly to those inferred in the past using simpler 1D models, but that the shape of the emergent wind can be deformed, very aspherical, and channeled by its environment. The thermal properties of winds for less massive progenitors very approximately recapitulate the 1D stationary solutions, while for more massive progenitors they deviate significantly due to aspherical fallback. The $Y_e$ temporal evolution in winds is stochastic, and there can be some neutron-rich phases. Though no strong r-process is seen in any model, a weak r-process can be produced and isotopes up to $^{90}$Zr are synthesized in some models. Finally, we find that there is at most a few percent of a solar mass in the integrated wind component, while the energy carried by the wind itself can be as much as 10-20% of the total explosion energy., Comment: 21 pages, 13 figures. Submitted to ApJ

Memory is one of the most essential cognitive functions serving as a repository of world knowledge and episodes of activities. In recent years, large-scale pre-trained language models have shown remarkable memorizing ability. On the contrary, vanilla neural networks without pre-training have been long observed suffering from the catastrophic forgetting problem. To investigate such a retentive-forgetful contradiction and understand the memory mechanism of language models, we conduct thorough experiments by controlling the target knowledge types, the learning strategies and the learning schedules. We find that: 1) Vanilla language models are forgetful; 2) Pre-training leads to retentive language models; 3) Knowledge relevance and diversification significantly influence the memory formation. These conclusions are useful for understanding the abilities of pre-trained language models and shed light on designing and evaluating new learning and inference algorithms of language models.

We calculate the gravitational-wave (GW) signatures of detailed 3D core-collapse supernova simulations spanning a range of massive stars. Most of the simulations are carried out to times late enough to capture more than 95% of the total GW emission. We find that the f/g-mode and f-mode of proto-neutron star oscillations carry away most of the GW power. The f-mode frequency inexorably rises as the proto-neutron star (PNS) core shrinks. We demonstrate that the GW emission is excited mostly by accretion plumes onto the PNS that energize modal oscillations and also high-frequency (``haze") emission correlated with the phase of violent accretion. The duration of the major phase of emission varies with exploding progenitor and there is a strong correlation between the total GW energy radiated and the compactness of the progenitor. Moreover, the total GW emissions vary by as much as three orders of magnitude from star to star. For black-hole formation, the GW signal tapers off slowly and does not manifest the haze seen for the exploding models. For such failed models, we also witness the emergence of a spiral shock motion that modulates the GW emission at a frequency near $\sim$100 Hertz that slowly increases as the stalled shock sinks. We find significant angular anisotropy of both the high- and low-frequency (memory) GW emissions, though the latter have very little power., Comment: accepted to PRD

An all polarization-maintaining figure-nine cavity fiber laser, which could be self-starting in low threshold state was reported. A phase shifter was used in the resonator structure to reduce the mode-locking threshold. When the pump power reached 120 mW, a self-starting conventional soliton mode-locking could be realized, with the central wavelength of 1530 nm and the pulse width of 614.6 fs. Then the pump power gradually increased to 470 mW, which realized the conversion from soliton pulse to noise-like pulse. In this mode-locking state, the laser output power is 63.2 mW, and the corresponding noise-like pulse energy is 5.69 nJ. The constructed laser has the advantages of low mode-locking threshold, self-starting, and can realize the conversion between ultrafast pulses and high-energy pulses only by adjusting the pump power, which has extensive application values.

A flat super-continuum spectrum light source of all-fiber structure based on noise-like pulse pumping was designed. In the dispersion-managed erbium-doped fiber laser, by adjusting the polarization state in the cavity, when the pump power was 450 mW, the stable noise-like pulse mode locking was achieved, the center wavelength was 1600 nm, and the pulse width was 303 fs. When the maximum pump power was 1 W, the direct output power of the resonator was 8.6 mW, and the lower power could not effectively expand the width of the super-continuum spectrum. Therefore, an erbium-doped fiber amplifier was designed for power amplification, and the maximum output power was 338 mW. The power-amplified noise-like pulse was coupled into the highly nonlinear fiber to obtain a super-continuum spectrum. The 20 dB spectral range of super-continuum spectrum is 1 530 nm ~ 2 300 nm, and in the range of 1 736 nm ~ 2 134 nm, the flatness of the spectrum is less than 0.5 dB.

An all-optical wavelength converter based on graphene oxide (GO) is proposed at the 1.9 µm band. The homemade GO-coated microfiber is acquired through the optical deposition method, which shows a remarkable nonlinear optical response. Stable conversion efficiency up to −45.52 dB is obtained with 1 nm wavelength interval, and the wavelength tuning range can reach 6 nm (1969-1975 nm). With fixed wavelength interval, the conversion efficiency can increase with the increase of pump power. Simultaneously, the fluctuation of conversion efficiency is ±0.41 dB within 2 hours. The demonstrated all-optical wavelength converter based on GO can play an outstanding role in the future of all-optical communications and networks.

The excessive emulation of the human visual system and the lack of connection between chromatic data and distortion have been the major bottlenecks in developing image quality assessment. To address this issue, we develop a new no-reference (NR) image quality assessment (IQA) metric that accounts for the impact of pre-attention and spatial dependency on the perceived quality of distorted images. The resulting model, dubbed the Pre-attention and Spatial-dependency driven Quality Assessment (PSQA) predictor, introduces the pre-attention theory to emulate early phase visual perception by refining luminance-channel data. Chromatic data are also processed concurrently by transforming images from RGB to the perceptually optimized SCIELAB color space. Considering that the gray-tone spatial dependency matrix conveys important texture properties that are closely related to visual quality, this matrix, as a mathematical solution for subsequent visual process emulation, is calculated along with its statistical features on both gray and color channels. To clarify the influence of different regression procedures on model output, support vector regression and AdaBoosting Back Propagation (BP) neural networks are adopted separately to train the prediction models. We thoroughly evaluated PSQA on four public image quality databases: LIVE, TID2013, CSIQ, and VCL. The experimental results show that PSQA delivers highly competitive performance compared with top-rank NR and full-reference IQA metrics.

为了实现2.1 μm波段光纤激光器输出多波长激光，设计了一种基于光纤Sagnac干涉仪的可调谐多波长掺钬光纤激光器。采用1.9 μm波段掺铥光纤激光器泵浦一段长3 m的掺钬石英光纤，获得2.1 μm波段的光放大；环形腔中，由保偏光纤和偏振控制器构成的光纤Sagnac干涉仪，实现2.1 μm波段周期滤波，获得了2.1 μm波段多波长激光，输出功率1 mW~15 mW可调谐，最多可观测到6个波长的激光输出。通过调节环形腔内偏振控制器，能够实现2.1 μm波段1~6个波长的调谐。

This paper concerns about modeling of tethered satellites systems (TSS). In this paper, tethers of TSS are modeled as chains of elastic rods connected by rigid joints. A group of spatial vectors are used to describe displacement, orientation and deformation of the rods, which can avoid the coupling of trigonometric functions of Euler angles. The coordinates of spatial vectors are chosen as the generalized coordinates of system. Equations of motion are derived and written in explicit form. A computationally efficient algorithm is developed to solve equations of motion. Computational complexity of the developed algorithm is reduced to O(n) (n denotes the number of rods). A numerical experiment is performed. Results about energy show energy conservation principle is obeyed. The same numerical experiment is also performed utilizing multibody software ADAMS. Validity of the presented algorithm is demonstrated by comparing numerical results of the two methods.

In order to exhume the buried signatures of ``missing planetary caustics'' in the KMTNet data, we conducted a systematic anomaly search to the residuals from point-source point-lens fits, based on a modified version of the KMTNet EventFinder algorithm. This search reveals the lowest mass-ratio planetary caustic to date in the microlensing event OGLE-2019-BLG-1053, for which the planetary signal had not been noticed before. The planetary system has a planet-host mass ratio of $q = (1.25 \pm 0.13) \times 10^{-5}$. A Bayesian analysis yields estimates of the mass of the host star, $M_{\rm host} = 0.61_{-0.24}^{+0.29}~M_\odot$, the mass of its planet, $M_{\rm planet} = 2.48_{-0.98}^{+1.19}~M_{\oplus}$, the projected planet-host separation, $a_\perp = 3.4_{-0.5}^{+0.5}$ au, and the lens distance of $D_{\rm L} = 6.8_{-0.9}^{+0.6}$ kpc. The discovery of this very low mass-ratio planet illustrates the utility of our method and opens a new window for a large and homogeneous sample to study the microlensing planet-host mass-ratio function down to $q \sim 10^{-5}$., 6 figures, 3 tables, submitted to RAA

A fault diagnosis method for bearing and gear based on deep learning waveform image recognition is proposed in this paper. The method can extract valid fault features automatically from time and frequency domain waveform curves of raw vibration signal and complete fault diagnosis. The training method for CNN model based on deep learning combined with transfer learning is designed, which needs only a small amount of faults sample data. The fault diagnosis algorithm and steps are given. The method is tested with a set of time and frequency domain vibration waveform data of gears and bearings in normal and different fault states. The results show that the proposed method has high recognition accuracies for the different types of faults and has good applicability.

Taking the improvement of the safety, reliability and maneuverability of nuclear power plant as the goal, the paper analyzes the development trend and demand of the application and technical approach of artificial intelligent technology in nuclear power plant safety management, operation management and equipment management. The overall development strategy of the intelligent instrument and control(I&C) system in nuclear power plant is proposed at first. The development route is then discussed, from the aspects of constructing the intelligent hardware, promoting the automation and intelligentization degree of I&C system respectively.

设计并实验研究了一种采用Fabry-Perot (F-P)光纤滤波器的2 μm波段宽带可调谐全光纤环形激光器，经过放大的1 550 nm半导体激光泵浦单模铥-钬共掺光纤(THDF)获得2 μm波段宽带增益。实验结果表明，该结构在2 μm波段获得了195 nm调谐范围的激光输出，线宽0.05 nm，边模抑制比66.98 dB。整个结构采用铥-钬共掺光纤放大结构，可使输出功率达到瓦级。

We experimentally demonstrate a passively mode-locking thulium-doped fiber laser based on the combination of the nonlinear polarization rotation (NPR) and the semiconductor saturable absorber mirror (SESAM). In contrast to SESAM mode-locking merely, the fiber lasers based on NPR working together with SESAM have more advantages. By using two mode-locking mechanisms, the nonlinear effect can be enhanced tremendously; then, the threshold of high-order harmonic mode-locking (HML) pulse trains can be decreased, and the pulses width can be compressed. The shapes of the pulses can also be reshaped better, and the HML pulse trains stability can be improved. The high repetition rate of 1.78 GHz is obtained by both NPR and SESAM in the experiment. Because of the variation of the gain-and-loss distribution in the cavity, the output wavelength of mode-locking fiber laser can be tuned from 1839 to 1890 nm, and the multiwavelength HML is also observed in the experiment.

Subjected to external lateral excitations, large-amplitude sloshing may take place in propellant tanks, especially for spacecraft in low-gravity conditions, such as landers in the process of hover and obstacle avoidance during lunar soft landing. Due to lateral force of the order of gravity in magnitude, the amplitude of liquid sloshing becomes too big for the traditional equivalent model to be accurate. Therefore, a new equivalent mechanical model, denominated the “composite model”, that can address large-amplitude lateral sloshing in partially filled spherical tanks is established in this paper, with both translational and rotational excitations considered. The hypothesis of liquid equilibrium position following equivalent gravity is first proposed. By decomposing the large-amplitude motion of a liquid into bulk motion following the equivalent gravity and additional small-amplitude sloshing, a better simulation of large-amplitude liquid sloshing is presented. The effectiveness and accuracy of the model are verified by comparing the slosh forces and moments to results of the traditional model and CFD software.

针对目前高速率信息传输的迫切需求，设计并实验了两路数字信号密集波分复用(DWDM)的大气激光通信结构。两路激光波长分别为1 539.76 nm和1 540.55 nm，采用强度调制，光信号经复用和放大后，由光学天线发射，经1 km大气信道传输，在接收端对光谱、波形和眼图进行了测量。实验结果显示，在弱湍流情况下，实现了两路光信号的解复用，并得到了较为清晰的波形图和眼图。两路数字信号的传输速率为20 Gbit/s时，Q因子仍达到5以上。

A multi-wavelength Brillouin erbium-doped fiber laser sensor is proposed and investigated experimentally. It is a linear laser cavity multi-wavelength fiber laser, formed by fixing two high-reflectivity Sangac loop mirrors at both ends. We investigate the laser system output characteristics and test the sensor performance for different temperature. Temperature/humidity and reliable linear-cavity fiber laser sensing operation were successfully achieved. Experimental results show that the temperature sensitivity is $$27.15$$ MHz/ °C and the measurement error caused by frequency drift is about $$\pm 0. 2 8 5$$ °C.

The transmission performance of orbital angular momentum(OAM) beam and Gaussian beam in atmospheric turbulent channel was studied and compared experimentally. The beam spreading, pointing error, power jitter and bit error rate of the two beams were measured respectively, the OAM beam loaded with modulated signals and the Gaussian beam were as carrier. The experimental results show that in the atmospheric turbulence channel, compared with Gaussian beam, beam spreading ratio of the OAM beams reduces by 10.5%, variance of power jitter falls 0.13, dispersion circle diameter of the pointing error decreases by 30.4%, and more focused on the distribution of the center of the beam axis. The lowest detection sensitivity of the OAM beam carrier system reaches −28.97 dBm, which improved 2.5 dB compared with that of Gaussian beam. The experimental results verify that OAM beam is less affected by turbulence than Gaussian beam in atmospheric turbulence channel, and the deterioration of beam quality of OAM beam is much less than Gaussian beam with the increase of turbulence intensity. The results of the experiment provide a reference for the development and application of free space laser communication in atmospheric turbulent channel.

The waste sand can be recycled to reduce the production cost. In this paper, the wet reclamation technology of phosphate modified animal glue used for foundry binder was studied. The results show that: the regeneration process is two times of continuous regeneration, the water sand ratio is 2:2.2, the regeneration time is 6min, the speed is 250rrmin, the ignition loss of the reclaimed sand is 0.30%, the mud removal rate is 82.5%, the average fineness is 51, the tensile strength of the reclaimed sand is 2.59MPa, which is similar to the original sand, and the wet reclamation effect is better.

Liquid sloshing of a large amplitude is prone to take place under excitation, especially when the gravitational intensity becomes small. A composite equivalent mechanical model is established to efficiently and accurately predict the slosh forces and moments exerted on a spherical propellant tank in a spacecraft. The modeling is based on an assumption of the dynamic equilibrium position of the liquid, which changes with time-dependent tank motion. Equivalent gravity is defined to describe the dynamic equilibrium position and act as a restoring force during sloshing. Sloshing of the liquid is assumed to take place around the dynamic equilibrium position. The validity of the modeling method is verified through numerical examples. Good stability and the ability to accurately predict the dynamic response under the violent sloshing of the composite model are revealed.

We develop a full-reference (FR) video quality assessment framework that integrates analysis of space–time slices (STSs) with frame-based image quality measurement (IQA) to form a high-performance video quality predictor. The approach first arranges the reference and test video sequences into a space–time slice representation. To more comprehensively characterize space–time distortions, a collection of distortion-aware maps are computed on each reference–test video pair. These reference-distorted maps are then processed using a standard image quality model, such as peak signal-to-noise ratio (PSNR) or Structural Similarity (SSIM). A simple learned pooling strategy is used to combine the multiple IQA outputs to generate a final video quality score. This leads to an algorithm called Space–TimeSlice PSNR (STS-PSNR), which we thoroughly tested on three publicly available video quality assessment databases and found it to deliver significantly elevated performance relative to state-of-the-art video quality models. Source code for STS-PSNR is freely available at: http://live.ece.utexas.edu/research/Quality/STS-PSNR_release.zip .

We integrally demonstrate 2 μm mode-locked pulses performances in all-fiber net anomalous dispersion cavity. Stable mode-locking operations with the center wavelength around 1950-1980 nm can be achieved by using the nonlinear polarization rotation structure and properly designing the dispersion management component. Conventional soliton is firstly obtained with a total anomalous dispersion cavity. Due to the contribution of commercial ultra-high numerical aperture fibers, net dispersion is reduced to -0.077 ps2. So that stretched pulse with 19.4 nm optical bandwidth is obtained and the de-chirped pulse-width can reach 312 fs using extra-cavity compression. Under pump power greater than 890 mW, stretched pulse can evolve into noise-like pulse with 41.3 nm bandwidth. The envelope and peak of such broadband pulse can be compressed with up to 2.2 ps and 145 fs, respectively. The single pulse energy of largely chirped stretched and noise-like pulse can reach 1.785 nJ and 1.53 nJ, respectively. Furthermore, extra-cavity compression can also contribute to a significant increase of peak power.

We demonstrate an actively mode-locked Ho-doped fiber laser. Actively mode-locked pulses are obtained with up to 5.039 GHz repetition rate. The shortest pulse width is 31 ps. Wavelength can be tuned from 2037nm to 2050nm.

We demonstrated a wide-spectrum pulsed fiber laser by using supercontinuum (SC) generate from a narrow pulse width fiber laser pump into high nonlinear fiber (HNLF). The pulse width of wide-spectrum pulsed fiber laser is 7.95ps and the repetition frequency is 4GHz with a 20nm bandwidth. It is found that the anomalous dispersion region near the zero dispersion wavelength has a better stability by observing the wide spectrum pulses in different bands.

A laser and microwave hybrid transmission system based on dual-wavelength Brillouin fiber laser is proposed and demonstrated. Laser and microwave hybrid transmission is achieved through experimental analysis.

A simple approach to generate stable microwave signals by heterodyning pump light and Stokes lasing light from a dual-wavelength Brillouin fiber laser is proposed and demonstrated. A 10-km-long single mode fiber is used as the Brillouin gain medium, and an ultranarrow linewidth distributed feedback laser is used as Brillouin pump, while a 4-m-long unpumped polarization maintaining erbium-doped fiber and subring cavity suppress unwanted side modes. A 10.7 GHz microwave signal is detected by photodetector and the signal linewidth is about 300 kHz. Signal to noise ratio of the microwave signal is about 50 dB. The power and frequency of microwave signal is highly stable, with almost no fluctuations over the test period. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1513–1516, 2014

A solar-photon sail space vehicle, or a sailcraft, is a new type of vehicle apt also for deep-space exploration. A sailcraft is pushed by the pressure of the solar irradiance on the sail. The sailcraft has large and highly flexible structure, and its motion involves a coupling of the orbit, the attitude and structural vibration. Based on the coupling effect of the orbit and the attitude, the theory of time-optimal control is used to design the transfer trajectory from an earth-centric orbit to a heliocentric polar orbit. This paper establishes the reduced dynamic model for a flexible solar sail with foreshortening deformation and coupling of its attitude and vibration. In the process of attitude control, the sailcraft will generate orbital deviations from the designed orbit as well as structural vibration. This is especially true when the sailcraft makes large-angle maneuvers: larger orbital deviations and structural vibrations are generated. When initial deviations and solar pressure disturbance torques are considered, the process of attitude control leads to greater accumulated error in the transfer trajectory, which demonstrates that the process of attitude control is important to the sailcraft mission.

A multiwavelength tunable fiber laser operating at 1.9 µm is demonstrated. A 4 m long Tm-doped single-mode fiber is pumped by a 1.57 µm fiber laser. A Sagnac fiber loop is used in the fiber laser cavity as a tunable filter, and the fiber loop consists of a 3-dB coupler, a polarization controller (PC), and a segment of polarization-maintaining fiber. Adjusting the PC state and pump power, multiwavelength laser with wavelength spacing of 2.5 nm 1895–1915 nm is observed. The number of output wavelength can be tuned precisely from one to four by adjusting the PC state. The 3-dB linewidth and side-mode suppression ratio are 0.045 nm and 45 dB, respectively. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:401–403, 2015

The solar sail is a new type of spacecraft for deep space exploration that is propelled by solar radiation pressure. The solar sail is large, has a large moment of inertia, and is highly flexible, and its motion involves a coupling of the orbit, the attitude, and structural vibration. With the coupling effect of the orbit and the attitude included, a non-Keplarian displaced solar orbit is designed. In the rotating frame, the solar sail has a stable equilibrium point, and an attitude controller is employed for coupled attitude-orbit control. With control, the time required for eliminating the orbital deflection is much larger than that required for the attitude deflection. Including the additional influence of the flexibility of the solar sail, the structure shows a sustained, high-frequency vibration, which also leads to sustained and high-frequency likewise small vibrations of the orbit and attitude. This work demonstrates the importance of including the structural flexibility into the coupling effect of...

We propose an all-fiber source at 3.8 μm with a high Tm-doped fiber as the gain medium pumped by a 1565-nm high-power fiber laser. With a laser diode at 1565 nm amplified by a high power erbium-doped fiber amplifier injecting into a segment of Tm-doped fiber, a fiber laser at 3.8 μm generates. Simultaneously, a second-order laser at 1.9 μm (dual-frequency of 3.8 μm) can be observed clearly. The laser has a threshold pump power of ∼300 mW and generates more than 176 mW continuous-wave output power with 1560 mW pump power. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:848–850, 2014

Ammonia is a major signal that regulates nitrogen fixation in most diazotrophs. Regulation of nitrogen fixation by ammonia in the Gram-negative diazotrophs is well-characterized. In these bacteria, this regulation occurs mainly at the level of nif (nitrogen fixation) gene transcription, which requires a nif-specific activator, NifA. Although Gram-positive and diazotrophic Paenibacilli have been extensively used as a bacterial fertilizer in agriculture, how nitrogen fixation is regulated in response to nitrogen availability in these bacteria remains unclear. An indigenous GlnR and GlnR/TnrA-binding sites in the promoter region of the nif cluster are conserved in these strains, indicating the role of GlnR as a regulator of nitrogen fixation. In this study, we for the first time reveal that GlnR of Paenibacillus polymyxa WLY78 is essentially required for nif gene transcription under nitrogen limitation, whereas both GlnR and glutamine synthetase (GS) encoded by glnA within glnRA operon are required for repressing nif expression under excess nitrogen. Dimerization of GlnR is necessary for binding of GlnR to DNA. GlnR in P. polymyxa WLY78 exists in a mixture of dimers and monomers. The C-terminal region of GlnR monomer is an autoinhibitory domain that prevents GlnR from binding DNA. Two GlnR-biding sites flank the -35/-10 regions of the nif promoter of the nif operon (nifBHDKENXhesAnifV). The GlnR-binding site Ⅰ (located upstream of -35/-10 regions of the nif promoter) is specially required for activating nif transcription, while GlnR-binding siteⅡ (located downstream of -35/-10 regions of the nif promoter) is for repressing nif expression. Under nitrogen limitation, GlnR dimer binds to GlnR-binding siteⅠ in a weak and transient association way and then activates nif transcription. During excess nitrogen, glutamine binds to and feedback inhibits GS by forming the complex FBI-GS. The FBI-GS interacts with the C-terminal domain of GlnR and stabilizes the binding affinity of GlnR to GlnR-binding site Ⅱ and thus represses nif transcription., Author summary GlnR is a global transcription regulator of nitrogen metabolism in Bacillus and other Gram-positive bacteria. GlnR generally functions as repressor and inhibits gene transcription under excess nitrogen. Our study for the first time reveals that GlnR simultaneously acted as an activator and a repressor for nitrogen fixation of Paenibacillus by binding to different loci of the single nif promoter region according to nitrogen availability. In excess glutamine, the feedback inhibited form of glutamine synthetase (GS) encoded by glnA within glnRA operon directly interacts with the C-terminal domain of GlnR and then controls the GlnR activity. Also, overexpression of glnR or deletion of glnA or mutagenesis of GlnR-binding site Ⅱ led to constitutive nif expression in the absence or presence of high (100 mM) concentration of ammonia. This work represents the first instance of a dual positive and negative regulatory mechanism of nitrogen fixation.

Objective To determine whether maternal β-human chorionic gonadotropin(β-hCG) level in second-trimester may be associated with subsequent development of pregnancy-induced hypertension(PIH). Methods Seven hundred and sixty-two women in mid-trimester were to have maternal urine β-hCG standardized concentrations and maternal serum β-hCG measurements. Their case histories were recorded and reviewed from mid-trimester to delivery. The relation was observed between maternal urine, serum markers and subsequent development of PIH. Results Among 762 women, 504 cases were normal pregnancies, 42 cases had PIH, 94 cases had premature rupture of membrane (PROM), 69 cases had preterm delivery (PD), 53 other cases were excluded by various reasons. The levels of maternal urine, serum β-hCG in PIH were (61.75±9.78) IU/L and (304.56±54.17) ng/mg respectively, which were higher significantly than normal pregnancy group ([20.65±7.61] IU/L and [146.34±47.81] ng/mg, P Conclusion The elevation of maternal mid-trimester urine, serum β-hCG levels is not only an early signal for dysfunction of placenta but also a dangerous signal for development of PIH. Second-trimester maternal urine β-hCG measurement proves to be superior to serum marker in clinical prediction.

Sand moulds are used in the casting process. However, after heating, the binder in the sand loses the binding properties, and the most part of the foundry sand has to be discarded from the process. The waste foundry sand after the regeneration can be recycled, and reclamation can reduce the production cost and lower waste emissions. The objective of this work was to investigate the possibility of reusing the animal glue binder waste foundry sand from the study of three regeneration methods. Studies with the waste foundry sand and reclaimed sand were performed in order to compare the results obtained with raw sand. The characterization of the samples was performed by scanning electron microscopy and energy dispersive spectroscopy. Results show that the waste sand was regenerated by mechanical regeneration, thermal regeneration and wet reclamation, respectively. The reclaimed sands have a better performance than the waste foundry sand, and are similar to raw sand. Further, the wet regeneration method is the best one among the three methods.

Sensors deployment optimization has become one of the most attractive fields in recent years. However, most of the previous work focused on the deployment problem in 2D space. Compared to the traditional form, sensors deployment in multidimensional space has greater research significance and practical potential to satisfy the detecting needs in complex environment. Aiming at solving this issue, a multi-dimensional space sensor network model is established, and the radar system is selected as an example. Considering the possible working mode of the radar system (e.g., searching and tracking), two distinctive deployment models are proposed based on maximum coverage area and maximum target detection probability in the attack direction respectively. The latter one is usually ignored in the previous literature. For uncovering the optimal deployment of the sensor network, the particle swarm optimization (PSO) algorithm is improved using the proposed weights determination scheme, in which the linear decreasing, the pooling strategy and the cloud theory are combined for weights updating. Experimental results illustrate the effectiveness of the proposed method.

SUMMARYWe have made a systematic study of the gait of a straight leg planar passive walking model through simulations and experiments. Three normalised parameters, which represent the foot radius, the position of the mass centre and the moment of inertia, are used to characterise the walking model.In the simulation, we have obtained the fixed points and the basins of attraction of the walking models with different parameter combinations by the aid of the cell mapping method. With the results of fixed points, we investigated the effects of parameter variations on the gait descriptors, including step length, period, average speed and energy inefficiency. A model that has a large basin of attraction has been obtained, and it can start walking far from its fixed point. However, the size of the basin of attraction is not a good measurement of robustness. Thus, we proposed floors with random slope angles or stairs with random heights to test robustness. Five hundred times of simulations with 100 non-dimensional time units were implemented for each parameter combination. The times that the walker failed to arrive at the end were recorded. The simulation results showed that the model with a larger foot radius and higher position of mass centre has a lower possibility of falling on uneven floors. A large moment of inertia is helpful for walking on a random slope angle floor, while low values of moment of inertia are good for navigating random stairs.Prototype experiments have validated the simulation results, which showed that models with larger feet have a longer step length and high speed. However, period differences were difficult to obtain in the experiments since the differences were very small. We have tested the sensitivity with the initial conditions of the models with different foot radii on a flat floor, and have also tested the robustness of the models on a floor with random slope angles. The times that the model reached the end of the floor were recorded. The experimental results showed that a large foot radius is good for improving the basin of attraction and robustness on uneven floors. Finally, the exceptions of the experiment are explained.