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頁次：113-117本文對微縮資料藏品作了簡要的解釋。文章摘要翻譯介紹了一些與中國有關的微縮資料藏品。例如，十八世紀到二十世紀期間在中國的商人，遊客，傳教士和外交官作品的微縮藏品；二十世紀二十年代美國國務院有關中國內務的文件；二十年代上海市政警署文件；四十年代中國的報業和出版物；中國傳教士口頭歷史匯集；中國軍事研究文件；以及1989年發生在北京的民運等。這些微縮資料藏品涵蓋中國近現代的政治，軍事，外交，宗教，新聞和文化等各領域。作者相信這些資料對研究中國的近現代史具有極為寶貴的參考價值。This article provided a brief explanation about microform collections. It translated and introduced some microform collections relating to China. For example, the microform collection on Western traders, travelers, missionaries and diplomats in China during 1700s and 1900s; The Files of U. S. Department of State Relating to Internal Affairs of China in 1920s; Shanghai Municipal Police File in 1920s and 1940s; Chinese Press and Related Publications in 1940s; China Missionaries Oral History Collection; Chinese Military Studies and Materials and Chinese People's Movement in the Spring of 1989. These microform materials cover all the fields of Chinese history in politics, military, religion, press and culture. The author believes that the resources are invaluable to the study of the Chinese contemporary history.

Given the overload trip of a slag conveyor caused by slag falling in a critical coal-fired boiler using blended Zhundong coal， the diagnosis and analysis were carried out from five aspects of coal quality analysis， slag falling location， furnace soot blowing test， aerodynamics field and burner nozzle. The causes of slagging and its falling were deduced. Moreover， the furnace was shut down and inspected to verify the inference. The results indicate that the blended Zhundong leads to a moderate slagging tendency. Under the influence of deformation and blockage of the peripheral air nozzles of the burner， ash from combustion deposits as slag on the side water-cooled wall， accumulating into slags that， upon falling， trigger the overload trip of the conveyor. In view of the coal quality characteristics of the blended Zhundong coal， the paper proposes preventive measures from both operational and maintenance perspectives， providing insights for the operation of boilers facing similar situations.

[Introduction] Accurate estimation of the Li-ion batteries' State of Health (SoH) is essential for future intelligent battery management systems. To solve the problems of poor quality of data features and difficulties in adjusting model parameters, this study proposes a method for estimating the SoH of lithium batteries based on singular value fixed-order noise reduction and the sparrow search algorithm which can optimize the gated recurrent unit (GRU) neural network.[Method] Firstly, three indicators highly correlated with SoH decay were extracted from the battery charge and discharge data. Noise reduction was applied to the features using singular value decomposition techniques to improve their correlation with SoH. Next, using the sparrow search algorithm to optimize the model structure and parameters of the GRU neural network improve the accuracy of estimation of SoH. Finally, the battery data sets from Centre for Advanced Life Cycle Engineering (CALCE) were used to verify the validity of the proposed model. [Result] The experimental results show that the model proposed in this study applies to the battery SoH estimation, with a maximum root mean square error (RMSE) of only 0.018 4. After data noise reduction and algorithm optimization, the RMSE of the GRU model is reduced by 55.41% compared to the initial model. [Conclusion] The method proposed in this paper accurately estimates SoH and can be used as a reference for practical engineering applications.

[Introduction] With the rapid development of AC/DC distribution networks and distributed generation technology, the role of DC microgrids in distribution networks is becoming increasingly important and will become an important component of future distribution networks. Due to the small coverage area and low line impedance of the DC microgrid, when an inter pole short circuit fault occurs, the fault current increases rapidly and has a large amplitude, which can reach more than 10 times the rated working current. This makes it difficult to set the protection of DC microgrids and requires high equipment selection, which restricts the rapid development of DC microgrids. [Method] In response to the above issues, taking the DC microgrid as the research object, starting from the working principle of inter pole faults in the DC microgrid, the fault characteristics on the DC side of the DC microgrid were analyzed. In response to the shortcomings of existing main current limiting methods, a voltage controllable fault current controller was proposed to achieve precise control of fault current. The simulation model of DC microgrid and fault current controller was built for simulation verification. [Result] The simulation results show that the fault current controller can significantly reduce the fault current and achieve precise control of the fault current, making the system controllable before and after the fault without locking the protection. During steady-state operation, the fault current controller can also assist the VSC (Voltage Source Converter) in further stabilizing the DC bus voltage. [Conclusion] To cooperate with the normal operation of the relay protection device and avoid VSC triggering overcurrent protection blocking, it is recommended to set the fault current control range between 1~2 pu.

[Introduction] With the development of new loads, such as distributed power sources and electric vehicles, DC(Direct Current) microgrids have the advantages of fewer commutation links and lower system losses than AC(Alternating Current) microgrids, and have become the current research hotspot. Due to the small coverage of the DC microgrid and access to a large amount of distributed power sources, the fault current rises quickly with a large amplitude when inter-pole short-circuit fault occurs, making it difficult to achieve differential coordination with traditional overcurrent protection used in AC distribution networks and posing a great challenge to fault localization. [Method] Therefore, in response to the characteristics of fault current in DC microgrids, the method for designing overcurrent protection setting value based on the precise control value of fault current through the integration of current limiting and protection was proposed. Combined with the reasonable capacity design of each branch, it can easily achieve differential coordination and accurately locate faults. [Result] A corresponding DC microgrid model is built on the PSCAD/EMTDC simulation platform. The proposed protection scheme is simulated and verified, and the result shows that the scheme can correctly locate the fault point and quickly remove the fault. [Conclusion] The proposed protection scheme can ensure the selectivity of overcurrent, which verifies the rationality of the scheme.

Manufacturing errors are one of the main causes of vibration and noise of gear transmission system，and the combination of multiple errors seriously affects the meshing performance of gear pairs. The influence degree and law of various manufacturing errors on meshing performance of herringbone gear pairs are mainly studied. Firstly，the manufacturing error model is established，and the actual tooth surface is constructed based on the theory of spatial coordinate transformation. Secondly，the influence law of different errors on the meshing performance of the gear pair is explored through the load distribution on the tooth surface，and the influence degree of different errors is explored based on the orthogonal experiment. Finally，the relationship between the influence of typical error types on the meshing performance of gear pairs and the system load is analyzed. The results show that the influence law of various errors on the meshing performance of gear pair is different，and the positive tilt deviation of helix direction has the most prominent influence on the meshing performance of gear pairs under heavy load.

Objective To explore the feasibility and accuracy of cisternal intracranial pressure (ICPc) monitoring after craniotomy in traumatic brain injury (TBI). Methods Four TBI patients underwent evacuation of hematoma were enrolled from May 2019 to July 2020. Ventriculostomy and cisternotomy were performed besides evacuation, and intracranial pressure (ICP) were monitored via the methods of extraventricular drainage (EVD) and cisternal drainage (CD) simultaneously for 7d after craniotomy. The correlation and consistency between ICPc and ventricular ICP (ICPv) were observed. Results The mean values of ICPv were (14.72±5.98), (11.10±4.49), (27.29±6.06) and (12.63±5.36) mm Hg, respectively. The mean values of ICPc were (14.32±5.44), (11.20±4.36), (25.46±5.00) and (12.46±5.21) mm Hg, respectively. The correlation coefficients were 0.977 (P=0.000), 0.961 (P=0.000), 0.892 (P=0.000) and 0.970 (P = 0.000), respectively. Using Bland⁃Altman consistency evaluation, the mean ICP difference between ICPv and ICPc was (0.21±1.36)mmHg, 95%LoA was ⁃2.440-2.870 (P=0.003). Conclusions ICPc and ICPv have good linear correlation and consistency. ICP monitoring through the method of cisternotomy and drainage can be applied to the clinical management of patients with TBI,and is likely to become an alternative method for ICPv. DOI：10.3969/j.issn.1672⁃6731.2020.07.007

The military aircraft health assessment has the problem of difficult application in engineering practice. The military aircraft is taken as the research object of health assessment, including task-oriented capability analysis, function analysis based on fault degradation and parametric health assessment. The two-level mapping of "aircraft-mission function-impact parameters" based on mission analysis is obtained as the object of health assessment. The degradation, severity and maximum entropy modification are comprehensively utilized. The results of aircraft health assessment are obtained by interval analytic hierarchy process and other methods. In combination with the specific example object and parameter analysis results, this assessment method has high reliability, and high engineering practical value.

The effect of multilayer interphase on the transverse cracking behavior of ceramic matrix composites（ CMCs） was simulated by micromechanical finite element method. The sub-layers of interphase were created according to their real thickness within a RVE model to describe the microstructure of multilayer interphase of CMCs. The finite element method was applied to analysis the stress by defining different material properties for the interphase sub-layers. On this basis,the cracking and debonding were simulated by extended finite element method and cohesive interfacial model,respectively.. After all,a simulation method for transverse cracking in the multilayer interphase was developed. The simulation results for cracking path within monolayer BN interphase,and multilayer interphase of different structure（ BN/Si C/BN and BN/Si C/BN/Si C/BN） were compared. It can be seen that the interfacial debonding occurs at the interface between fiber and interphase for CMCs with multilayer interphase. Moreover,the transverse cracking strain of multilayer interphase is higher than that of monolayer interphase and the location of cracks for the two cases is very different.

A surrogate model was established to optimize needling process parameters of three dimensional needled C/C-SiC composites by using back propagation (BP) neural network and improved genetic algorithm. The relationship between needling process parameters and composites stiffness was obtained. The stiffness prediction obtained by BP neural network is in good agreement with the finite element calculated results. The maximum error of training data is 0.526%, and the maximum error of test data is 0.454%. Thus, the BP neural network model exhibits the high prediction accuracy. The genetic and optimization strategies of genetic algorithm were improved to optimize the needling process parameters. The calculated needling process parameters by the model can significantly improve the stiffness of the C/C-SiC composites. The in-plane tensile modulus increase by 11.07% and 11.48%, and the out-of-plane tensile modulus increase by 49.64% and 48.13%, respectively. The comprehensive stiffness performance of composite material increase by 18.17% and 18.21%, respectively.

Ground Penetrating Radar (GPR) is a widely used non-destructive testing tool. Constructing an appropriate forward model is crucial for GPR to perform a full-waveform inversion of layered media. In this paper, a forward model for the quasi-monostatic Stepped-Frequency GPR (SFGPR) is proposed. In the model, the GPR and its interaction with the layered medium are represented as a linear equation in which the effects of the antennas are represented by a set of frequency-dependent transfer functions. To verify the accuracy of the proposed model, the authors constructed a quasi-monostatic SFGPR in a laboratory condition and performed a full-waveform inversion of the measurement signals of plasterboard and woodblock with known thickness. In the inversion results, the thickness estimation errors of the plasterboard and woodblock are not more than 0.3 mm, indicating that the proposed forward model has a very high accuracy. The inversion performances of the quasi-monostatic and monostatic SFGPR are further compared for the layered medium constructed with plasterboard and woodblock, which has a small permittivity difference. The results show that the quasi-monostatic SFGPR can obtain more accurate inversion parameters. By estimating the Signal to Noise Ratio (SNR) of the reflected signal from the interface, it is found that the SNR obtained by the quasimonostatic configuration is 10 dB higher than that of the monostatic; therefore, the quasi-monostatic GPR has the better inversion performance.

Based on transmission line theory and impedance transition, we design an ultra-wideband Transverse ElectroMagnetic (TEM) horn antenna that takes advantage of index gradient structure and loading techniques and is optimized for highway Ground Penetrating Radar (GPR) applications. We use numerical simulation to analyze the effects of different curved surfaces as an extension of the antenna and further improve the antenna performance by the use of a metallic reflective cavity and distributed resistor loading. We then fabricated an antenna based on the optimization results and determined the Voltage Standing Wave Ratio (VSWR) of the antenna to be less than 2 for bandwidths ranging from 0.9–12.6 GHz. The waveform fidelity of the antenna is also good and when we applied this antenna to highway scenarios, it achieved good results.

In the emergency communication,UAVs (unmanned aerial vehicle) are used more and more widely,and a V2I (vehicle to infrastructure) vehicle communication technology based on UAV was proposed.Because of the communication distance and the shelter of the terrain,the ground vehicle and the base station may not connect directly.At this time,the UAV can be used as communication relay.In the process of communication,in order to meet the fairness of ground vehicle communication,a time interval less than the coherence time was selected based on the coordinates of moving ground vehicles,the transmission rate between vehicles in each time interval are calculated to maximize the minimum transmission rate as the optimization goal.In order to solve this problem,the entire communication process was dispersed.First,UAV flight trajectory to maximize the minimum transmission rate at each time interval within the range of the UAV flight path was calculated to get the whole communication process trajectory.Simulation results show that through the path planning of UAV,the information transmission rate of the vehicle is obviously better than the transmission rate under the fixed position of UAV.

A Multiple-Input Multiple-Output (MIMO) ultra-wideband radar can detect the range and azimuth information of targets in real time. It is widely used for geological surveys, life rescue, through-wall tracking, and other military or civil fields. This paper presents the design of an ultra-wideband pseudo random coded MIMO radar that is based on Radio Frequency (RF) switches and implements a MIMO radar system. RF switches are employed to reduce cost and complexity of the system. As the switch pressure value is limited, the peak power of the transmitting signal is 18 dBm. The ultra-wideband radar echo is obtained by hybrid sampling, and pulse compression is computed by Digital Signal Processors (DSPs) embedded in an Field-Programmable Gate Array (FPGA) to simplify the signal process. The experiment illustrates that the radar system can detect the range and azimuth information of targets in real time.

The tension-compression fatigue behavior for needled C/SiC composite at room temperature was studied and compared with the properties under tension-tension fatigue loading. The results show that the tension-compression fatigue strength of the needled C/SiC composites is slightly lower than that under tension-tension loading. Hysteresis phenomenon can be observed under both loading stations. The loops move to the right and their slopes and areas increase as the cycles increase. The microstructure of the composites and the morphology of the fractured surfaces of the failure specimens can be observed by SEM. It shows that in addition to the matrix cracking and interface debonding, which is vertical to the loading direction, the meso failure mechanism under tension-compression cyclic loading also includes matrix cracking and interlayer delamination parallel to loading direction, which can make the stress state within fibers worse and finally weakens the fatigue strength of needled C/SiC composites under tension-compression loading.

Terahertz holographic imaging has broad applications in the field of personal security verification, concealed weapon detection, and non-destructive testing. To suppress the range ambiguity, a fast sparse image reconstruction approach and imaging scheme is proposed for three-dimensional terahertz holography. The proposed algorithm establishes the terahertz imaging geometry and corresponding echo model. The range ambiguity is eliminated using the random step frequency method, and a frequency shift procedure is applied to recover the targets with a high computational efficiency. Simulation and experimental results verify the proposed algorithm.

In this study, we investigated the use of a half-ellipse dipole with distributed resistor-loading. By improving the structure of the antenna arms and using distributed resistor-loading technology, the current reflection at the end of dipole is significantly reduced, the input impedance is improved, and the operation bandwidth is widened. We decreased the backward radiation of the antenna with a cubic metal-reflective cavity and also improved the ground penetration ability. The proposed antenna was simulated and designed with electromagnetic computing software; on the basis of the design results, we fabricated the antenna sample. Measurement results of the return loss and radiation characteristics of the proposed antenna confirm the validity of the simulation. We applied the proposed antenna in a GPR system as an underground target detection experiment; on the basis of the experimental results, we conclude that the antenna is able to meet the needs of GPR systems.

This paper presents the design of a handheld pseudo random coded Ultra-WideBand (UWB) radar for human sensing. The main tasks of the radar are to track the moving human object and extract the human respiratory frequency. In order to achieve perfect penetrability and good range resolution, m sequence with a carrier of 800 MHz is chosen as the transmitting signal. The modulated m-sequence can be generated directly by the high-speed DAC and FPGA to reduce the size of the radar system, and the mean power of the transmitting signal is 5 dBm. The receiver has two receiving channels based on hybrid sampling, the first receiving channel is to sample the reference signal and the second receiving channel is to obtain the radar echo. The real-time pulse compression is computed in parallel with a group of on-chip DSP48E slices in FPGA to improve the scanning rate of the radar system. Additionally, the algorithms of moving target tracking and life detection are implemented using Intel’s micro-processor, and the detection results are sent to the micro displayer fixed on the helmet. The experimental results show that the moving target located at less than 16 m far away from the wall can be tracked, and the respiratory frequency of the static human at less than 14 m far away from the wall can be extracted.

Lunar Penetrating Radar (LPR), which is one of the most important science payloads onboard the Chang'E-3 (CE-3) rover, is used to obtain electromagnetic image less than 100 m beneath the lunar surface. This paper describes the system composition and working mechanism of the LPR and presents a detailed analysis of its data. We investigated special signal-processing methods and present the result of channel-1 data. The result shows that the effective echo occurs at depths greater than 100 m. Moreover, an unusual reflection exists at depth of 40 m, which may be the boundary of two geological units beneath the lunar surface.

The classical Frequency-Wavenumber (F-K) imaging algorithm can efficiently reconstruct the image for homogeneous medium; however, it cannot generate focused and properly-located images for layered medium. Considering the electrical properties of individual layer and the discontinuity between layers, the phase shift migration for layered medium is derived in this paper. The analysis on the backscattered transfer function shows that some assumptions and mathematical approximations are applied in the proposed method. The numerical and experimental results are presented to show the feasibility of the proposed method for real-time imaging of layered medium.

Video Synthetic Aperture Radar (ViSAR) system offers high imaging frame rate, and high resolution, and it is consequently used to investigate and locate near-moving targets. Compared with microwave SAR, the practical application of ViSAR is restricted by motion compensation caused by short wavelength. Even slight platform vibrations cause significant variations in the phase of echo signal.Thus, it is imperative to analyze the motion compensation and the error of ViSAR. In this study, the results show that imaging is affected less in the direction of flight direction and by low vibration in the direction of the slant range. In contrast, high-frequency vibration in the direction of the slant range requires higher compensation accuracy. Given the particularity of ViSAR's motion compensation, a compensation scheme is designed to achieve high compensation precision .The effectiveness of the scheme is verified by ViSAR imaging simulation experiments.

To suppress airwave interference, a time-domain coded electromagnetic exploration method is proposed with Pseudo-Random Binary Sequences (PRBS) code as the source signal. Based on the PRBS code and receiving voltages, which are recorded simultaneously, the impulse response of the earth can be obtained by the time-domain deconvolution signal recovery method, and the target information is effectively contained in the impulse response. The selection methods of clock frequency and code length were analyzed and field experiments were carried out, which demonstrated that the signal quality of the EM data could be improved by decreasing the clock frequency, or increasing the code length. The proposed method could greatly suppress the airwave interference and effectively identify underground anomalies.

A High-speed digital sampling technology suitable for periodical impulse radar signal is proposed in this paper. One bit high-speed quantize is constructed by differential comparator in FPGA. Time-interleaved digital sampling and buffer encoding are used to one bit stream based on the internal multi-phase clock of FPGA, to achieve sampling rate higher than 1 GHz. High speed digital sampling is realized by the accumulation of one bit sampling data with different comparison levels. An 8 bit, 1.6 GHz ADC based on the proposed method is realized on XC2V3000 Xilinx’s FPGA, which is successfully applied in GPR. The proposed method has the advantages of low cost and power consumption as compared with real sampling, and exhibits higher efficiency as compared with equivalent sampling.

Constructing digital war-field electromagnetic environment needs to model and simulate the transmitting course of electric waves combining various environment factors. The Parabolic Equation (PE) described model is suitable for computing the waveguide propagation characteristics from an area in the horizon to that over the horizon, and there is Split-Step Fourier Transform (SSFT) algorithm to resolve the model. But it is an iterative method based on step length and is difficult to be realized in parallels, thus it is difficult to meet the requirement time wise and bring the obstacles to constructing war-field electromagnetic environment fastly. This paper puts forward a parallel computing method based on matrix transposing, and realizes parallel computing of the algorithm by constructing two-dimensional matrixes and distributing them to different process in line or in row. The method makes full use of the operating ability of calculation clusters, decreasing computing time. The result of computer simulating shows that parallel algorithm can have a speedup as four times large as that of sequential algorithm, thus verifies the effectiveness of the method.

DOI：10.3969/j.issn.1672-6731.2011.05.006

Software development based on message driven framework has become an important pattern for big data application system.The message management module which is an important part of whole framework was designed and implemented.The basic format of message and the standard of message management was defined,its function was realized,and the advantages through a case were shown.

Objective: To characterize the prevalence and species/genotypes of Cryptosporidium spp. in farmed pigs in the north of the Yangtze River in Anhui Province., Methods: A total of 500 samples of pig feces were obtained from seven largescale pig farms in the north of the Yangtze River in Anhui Province. PCR and sequences analysis of the small subunit rDNA gene were used to detect and identify the Cryptosporidium species/genotypes., Results: The overall prevalence of Cryptosporidium was 4.8% (24/500). Additionally, Cryptosporidium prevalence was 40.0% in Qianshan and 6.3% in Chuzhou, respectively. No Cryptosporidium infection was found in other sampling areas. The DNA sequence analysis of the SSUrDNA gene revealed that all of the isolates represented C. scrofarum . The Cryptosporidium infection rate (9.1%) of pigs (> 60 days) was significantly higher than the rates of both pigs (< 30 days) and pigs (30-60 days) (both P < 0.01)., Conclusions: C. scrofarum in the farmed pigs in the north of the Yangtze River in Anhui Province may be a source of Cryptosporidium infection and pose a potential public health threat to humans and other animals, and therefore, the status should be paid more attention to.

Objective: To understand the quality of malaria blood examinations in township-level hospitals, so as to provide the evidence for continuing the malaria blood examinations in the stage of post-malaria elimination., Methods: A total of 64 township hospitals were investigated and 640 negative malaria blood slides were scored individually according to 10 indicators in "Malaria Elimination Technical Scheme" in 2013 and 2014. The single and multiple indicators were calculated, and the work of blood examinations and situation of technicians were investigated. The data of malaria blood examinations and patient discovery in township hospitals of Nantong City were collected and analyzed during the period of 2011-2014., Results: For the single indicator, 29.5% of the thick blood films did not reach the standard, and 35.8% of thin blood films did not reach the standard. For the multiple indicators, blood slides with more than 4 indicators below the standard (poor quality) accounted for 32.5%. From malaria blood examinations and malaria situation, the number of slides was 194 635 during the period of 2011-2014, and there were no local vivax malaria casesin 4 consecutive years from 2011 to 2014, and local malaria has been effectively controlled in Nantong City. For health facilities where malaria patients initially presented, the township and village level accounted for 16.3%, and county and higher level accounted for 83.7%., Conclusions: The quality of malaria blood examinations in township level hospitals of Nantong City is not high and the microscopic examination has a relatively low efficiency in the discovery of malaria cases. A new model for malaria blood examinations needs to be further explored.