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In the context of the rapid development of the Internet and the Internet of Things technology, services based on location information have received more and more attention, and people gradually have higher expectations for the quality and experience of positioning services. At present, outdoor positioning technology is becoming mature, but different from empty outdoor areas, there is a highly complex indoor environment with many interference factors, so it is difficult to receive effective satellite signals. To realize the smooth transition of whole-field positioning, it is necessary to study an economical and efficient indoor positioning technology. The existing indoor positioning technologies have some problems, so this paper comprehensively uses the resource-rich Wi-Fi signal, Frequency Modulation (FM) signal and Digital Terrestrial Multimedia Broadcast (DTMB) signal as the positioning data sources, and proposes a fingerprint fusion positioning method based on the wireless signal distribution characteristic. Experiments show that the proposed method improves localization accuracy by 30% compared to localization with Wi-Fi alone.

An ultra-highly precise and long-term stable frequency transmission system over 120 km commercial fiber link has been proposed and experimentally demonstrated. This system is based on digital output compensation technique to suppress phase fluctuations during the frequency transmission process. A mode-locked erbium-doped fiber laser driven by a hydrogen maser serves as an optical transmitter. Moreover, a dense wavelength division multiplexing system is able to separate forward and backward signals with reflection effect excluded. The ultimate fractional frequency instabilities for the long-distance frequency distributed system are up to 3.14×10-15 at 1 s and 2.96×10-19 at 10 000 s, respectively.

We demonstrate a frequency transfer scheme for over 1000 km optical fiber link with mode locked pulse train as the frequency carrier. The fractional frequency instability was measured as 2.75x10−15/s and 3.91x10−21/120000 s.

We demonstrate a sub-picosecond resolution time-offset measurement over 100 km long fiber using asynchronized dual-comb linear optical sampling.

A high precision multi-node clock network for multiple users was built following the precise frequency transmission and time synchronization of 120 km fiber. The network topology adopts a simple star-shaped network structure. The clock signal of a hydrogen maser (synchronized with UTC) was recovered from a 120 km telecommunication fiber link and then was distributed to 4 sub-stations. The fractional frequency instability of all substations is in the level of 10-15 in a second and the clock offset instability is in sub-ps in root-mean-square average.

An ultrahigh stable phase-locked loop system for synchronization of an optical frequency comb to a hydrogen maser has been proposed and experimentally demonstrated. A mathematical model has been set up to investigate the feasibility and steady state of the phase-locking system. The fractional frequency instability is evaluated by measuring the mixed-phase signal of an improved experimental system. Experimental results show that the fractional frequency instability of the phase-locked loop system lies from 8.83×10

A precise multi-node frequency dissemination scheme for multiple users by feed-forward digital compensation technique is demonstrated. The fractional frequency instabilities of the third-level nodes were measured as 1.79×10−15/s (2.61×10−18/100s) and 1.45×10−15/s (4.58×10−18/100s).

Precision time synchronization between two remote sites is desired in many applications such as global positioning satellite systems, long-baseline interferometry, coherent radar detection and fundamental physics constant measurements. The recently developed frequency dissemination technologies based on optical fiber link have improved the transfer instability to the level of 10−19/day at remote location. Therefore it is possible to keep clock oscillation at remote locations continuously corrected, or to reproduce a “virtual” clock on the remote location. However the initial alignment and the correction of 1 pps timing signal from time to time are still required, besides the highly stabilized clock frequency transfer between distant locations. Here we demonstrate a time synchronization based on an ultra-stable frequency transfer system via 120-km commercial fiber link by transferring an optical frequency comb. Both the phase noise compensation in frequency dissemination and temporal basis alignment in time synchronization were implemented by a feed-forward digital compensation (FFDC) technique. The fractional frequency instability was measured to be 6.18 × 10−20 at 2000 s. The timing deviation of time synchronization was measured to be 0.6 ps in 1500 s. This technique also can be applied in multi-node fiber network topology.

We demonstrate feed-forward digital compensation technique applied in both precise frequency transfer and time synchronization. The fractional frequency instability was 6.18×10−20 at 2000 s and RMS variation of time synchronization was sub-40 ps.

We demonstrate a feed-forward digital compensation scheme in an optical frequency comb based microwave frequency dissemination system over 120-km telecommunication fiber link. The dissemination fractional frequency instability (Λ-counter) was measured at 5.28×10−16/s.

研究了强磁场对射频溅射沉积Fe-Si-O薄膜的微结构和磁性能的影响. 在O2流量比小于1.0%、外加磁场低于1.0 T的溅射条件下, 得到了中孔型、相分离型和混合型3种典型的样品宏观形貌, 表明强磁场不但影响等离子体的分布而且影响溅射原子的角分布. 在O2流量比大于2.0%,外加磁场高于2.0 T的条件下制备的Fe-Si-O薄膜中, 经X射线衍射分析发现了强(110)取向的Fe3O4相；磁性测量发现垂直膜面方向上的剩磁和矫顽力大于平行膜面情况. 这些结果表明在薄膜沉积过程中, 强磁场不但使磁性薄膜取向, 而且在膜中诱导出了显著的垂直磁各向异性.

Recent neuroanatomical studies have revealed a direct hypothalamocerebellar histaminergic pathway. However, the functional significance of the histaminergic fibers in the cerebellum is not yet clear. In this study, the effects of histamine on the firing of cerebellar Purkinje cells (PCs) were investigated in vitro. Histamine predominantly produced excitatory (106/111, 95.5%) and in a few cases inhibitory (5/111, 4.5%) responses in PCs. The histamine-induced excitation was not blocked by perfusing the slice with low Ca2+ high/Mg2+ medium (n = 8), supporting a direct postsynaptic action of histamine. The histamine H2 receptor antagonist ranitidine effectively blocked the excitatory response of PCs to histamine (n = 20), but triprolidine, an H1 receptor antagonist, could not significantly block the histamine-induced excitation, or only very slightly decreased the excitatory effect of histamine on the cells (n = 13). On the other hand, the highly selective H2 receptor agonist dimaprit mimicked the excitatory effect of histamine on PCs and this dimaprit-induced excitation was also blocked by ranitidine (n = 20), but not triprolidine (n = 8). However, the H1 receptor agonists betahistine and 2-thiazolylethylamine did not show any effect on the PCs (n = 9 and 14). These results reveal that histamine excites cerebellar PCs via H2 receptors and suggest that the hypothalamocerebellar histaminergic fibers may play an important role in functional activities of the cerebellum.

An ultrahigh stable phase-locked loop system for synchronization of an optical frequency comb to a hydrogen maser has been proposed and experimentally demonstrated. A mathematical model has been set up to investigate the feasibility and steady state of the phase-locking system. The fractional frequency instability is evaluated by measuring the mixed-phase signal of an improved experimental system. Experimental results show that the fractional frequency instability of the phase-locked loop system lies from 8.83×10−16 at 1 s to 1.67×10−19 at 1000 s, which indicates our proposed phase-locking system possesses ultrahigh measurement precision with good long-term stabilization performance.

Owing to the particularity of civil explosives, the site selection of a civil explosive distribution center has remarkable difference from the site selection of an ordinary distribution center. Particular consideration should be given to the safety condition. SOM (Self-Organizing Map) neural network is used to analyze and process the factors that influence the site selection of a civil explosive distribution center. Optimization and decision are made on multiple candidate solutions. The calculation analysis indicates this method realizes the classification of relations through competition among neurons and can perfectly meet the requirements of the decision making on site selection of a civil explosive distribution center.

The aim of load matching at truck is to make the truck cargo stowage reasonable in volume, weight and loading sequence of a distribution area, to raise efficiency of truck and to reduce costs of the distribution. An effectual truck stowage planning model is built. The model can equilibrate the truck cargo weight and the volume and make the transport resources more effective. The opinion of backtrack programming for use the truck load matching is proposed, which is an important technique for solving combinatorial search problems and can choose suitable cargo for truck in a short time. This technique is proved to be highly effective by examples.

The purpose of these experiments was to test the hypothesis that a conditioned nictitating membrane reflex can be acquired in decerebrate rabbits in the absence of the cerebellum. Experiments examining the effects of large cerebellar lesions on the acquisition and performance of the conditioned reflex were performed in acutely prepared decerebrate rabbits. Most lesions encompassed all of the cerebellar nuclear regions ipsilateral to the eye receiving the unconditioned stimulus. In all rabbits included in this study the continuity between the cerebellar nuclei and the brainstem was interrupted, even in those preparations in which small regions of the nuclei were present in the lateral hemisphere. The findings demonstrate that these animals could acquire the conditioned reflex independent of whether conditioning had occurred prior to the cerebellectomy. Strong associativity was found between the latency of the conditioned response and the interstimulus interval between the conditioned and unconditioned stimuli. The behavior of the conditioned reflex observed in the decerebrate-decerebellate animals different from that reported for awake intact rabbits in two ways. Once the conditioned behavior had been acquired, the percent of trials showing conditioned responses was somewhat less in decerebrate-decerebellate rabbits and was also more variable in these animals. The data demonstrate that the nictitating membrane reflex can be classically conditioned in the absence of the cerebellum, indicating that this structure is neither necessary nor sufficient for the acquisition of this type of conditioned behavior. In addition, an hypothesis is presented which addresses the difference between the data reported here and those previously reported by other laboratories based on observations in awake intact animals.