A multi-source information fusion layer counting method for penetration fuze based on TCN-LSTM

When employing penetration ammunition to strike multi-story buildings,the detection methods using acceleration sensors suffer from signal aliasing,while magnetic detection methods are susceptible to interference from ferromagnetic materials,thereby posing challenges in accurately determining the number of layers.To address this issue,this research proposes a layer counting method for penetration fuze that incorporates multi-source information fusion,utilizing both the temporal convolutional network(TCN)and the long short-term memory(LSTM)recurrent network.By leveraging the strengths of these two network structures,the method extracts temporal and high-dimensional features from the multi-source physical field during the penetration process,establishing a relationship between the multi-source physical field and the distance between the fuze and the target plate.A simulation model is developed to simulate the overload and magnetic field of a projectile penetrating multiple layers of target plates,capturing the multi-source physical field signals and their patterns during the penetration process.The analysis reveals that the proposed multi-source fusion layer counting method reduces errors by 60% and 50% compared to single overload layer counting and single magnetic anomaly signal layer counting,respectively.The model's predictive performance is evaluated under various operating conditions,including different ratios of added noise to random sample positions,penetration speeds,and spacing between target plates.The maximum errors in fuze penetration time predicted by the three modes are 0.08 ms,0.12 ms,and 0.16 ms,respectively,confirming the robustness of the proposed model.Moreover,the model's predictions indicate that the fitting degree for large interlayer spacings is superior to that for small interlayer spacings due to the influence of stress waves.

Image Segmentation-P300 Selector: A Brain–Computer Interface System for Target Selection

Brain–computer interface (BCI) systems, such as the P300 speller, enable patients to express intentions withoutnecessitating extensive training.However, the complexity of operational instructions and the slow pace of characterspelling pose challenges for some patients. In this paper, an image segmentation P300 selector based on YOLOv7-mask and DeepSORT is proposed. The proposed system utilizes a camera to capture real-world objects forclassification and tracking. By applying predefined stimulation rules and object-specificmasks, the proposed systemtriggers stimuli associated with the objects displayed on the screen, inducing the generation of P300 signals in thepatient’s brain. Its video processing mechanism enables the system to identify the target the patient is focusing oneven if the object is partially obscured, overlapped, moving, or changing in number. The system alters the target’scolor display, thereby conveying the patient’s intentions to caregivers. The data analysis revealed that the selfrecognitionaccuracy of the subjects using this method was between 92% and 100%, and the cross-subject P300recognition precision was 81.9%–92.1%. This means that simple instructions such as “Do not worry, just focuson what you desire” effectively discerned the patient’s intentions using the Image Segmentation-P300 selector. Thisapproach provides cost-effective support and allows patients with communication difficulties to easily express theirneeds.

Wheel Setting Error Modeling and Compensation for Arc Envelope Grinding of Large-Aperture Aspherical Optics

Precision grinding is a key process for realizing the use of large-aperture aspherical optical elements in laser nuclear fusion devices,large-aperture astronomical telescopes,and high-resolution space cameras.In this study,the arc envelope grinding process of large-aperture aspherical optics is investigated using a CM1500 precision grinding machine with a maximum machinable diameter ofΦ1500 mm.The form error of the aspherical workpiece induced by wheel setting errors is analytically modeled for both parallel and cross grinding.Results show that the form error is more sensitive to the wheel setting error along the feed direction than that along the lateral direction.It is a bilinear function of the feed-direction wheel setting error and the distance to the optical axis.Based on the error function above,a method to determine the wheel setting error is proposed.Subsequently,grinding tests are performed with the wheels aligned accurately.Using a newly proposed partial error compensation method with an appropriate compensation factor,a form error of 3.4μm peak-to-valley(PV)for aΦ400 mm elliptical K9 glass surface is achieved.

Modeling the impacts of climate variability and hurricane on carbon sequestration in a coastal forested wetland in South Carolina

The impacts of hurricane disturbance and climate variability on carbon dynamics in a coastal forested wetland in South Carolina of USA were simulated using the Forest-DNDC model with a spatially explicit approach. The model was validated using the measured biomass before and after Hurricane Hugo and the biomass inventories in 2006 and 2007, showed that the Forest- DNDC model was applicable for estimating carbon dynamics with hurricane disturbance. The simulated results indicated that Hurricane Hugo in 1989 substantially influenced carbon storage immediately after the disturbance event. The simulated net ecosystem exchange (NEE) for the 58-year period (1950-2007) indicated that the hurricane reduced CO2 sequestration due primarily to the increased decomposition of a large amount of litter and woody debris, including fallen trees (over 80% of pre-hurricane trees), debris and branches, and dead roots. The inter-annual fluctuation of soil CO2 flux showed that the climate variability interfered substantially soil carbon dynamics in the forest. The results showed that there were substantial spatial and temporal differences in CO2 flux (3.2 - 4.8 Mg·C·ha–1) and wood biomass due to the differences in physical and biogeochemical characteristics in the forest.

Modeling of Slab Induction Heating in Hot Rolling by FEM

FEM (Finite Element Method) has been widely used to solve temperature in hot rolling. The heat gen-erating rate of electromagnetic field has been discussed in order to improve the efficiency and accuracy in the solution of induction heating. A new heat generating rate model was proposed and derived from the calculated results by FEM software in consideration of work frequency, source current density, and the air gap between induction coil and slab. The calculated distribution of heat generating rate in the skin depth by the model is satisfying and reliable compared with that of FEM software. Then, the mathematic model of the heat generating rate model is considered as the density of heat reservoir to solve the temperature in induction heating. Moreover, the temperature evolution of slab in induction heating from a hot rolling plant has been solved by the developed FE code and the calculated temperature has a good agreement with the measured value. Therefore, the heat generating rate model is suitable and efficiency to solve the temperature in induction heating by FEM.

农田土壤有机碳含量对作物产量影响的模拟研究

【目的】探求土壤有机碳含量对作物产量的影响,以期为保障国家粮食安全和耕地持续利用与管理提供决策依据。【方法】利用农田生态系统生物地球化学模型DNDC,针对中国东北、华北、西北、中南、华东和西南6个典型农业区域,每个区域选择各自典型的种植模式和现行的农田管理措施,在各自特定的土壤和气候条件下,输入并运行模型,模拟考察在其它投入条件不变的情况下,改变土壤有机碳本底值对作物产量的影响。【结果】当土壤有机碳含量(SOC)增加1g C.kg-1,东北地区玉米产量可增加176kg·hm-2;华北地区夏玉米与冬小麦轮作,产量可增加约454kg·hm-2;西北地区春玉米产量约可增加328kg·hm-2;中南地区单季水稻产量可增加约185kg·hm-2;华东地区双季稻产量可增加约266kg·hm-2;西南地区水稻与冬小麦轮作产量可增加约229kg·hm-2。【结论】在其它投入既定的条件下,全国各地区均存在通过提高耕地土壤有机碳含量来增加作物产量的潜力。保持较高水平的土壤有机碳含量对节本增效具有十分明显的作用。

东北三省耕地土壤有机碳储量变化的模拟研究

利用农业生态系统生物地球化学模型(DNDC)方法,在GIS区域数据库支持下运行模型,研究了东北三省地区土壤有机碳储量状况,及其在现行农田管理措施下的变化特征。结果表明,以1998年为例,东北三省耕地土壤有机碳(SOC)储量(0-30cm土层)约为124 348万t,黑龙江、吉林和辽宁省分别占58.4％、25.5％和16.1％;在目前的农作制度下土壤有机碳库处于严重的负平衡,每年净丢失有机碳3122万t,黑龙江、吉林和辽宁省分别占59.3％、25.9％和14.8％;单位面积耕地SOC年减少量高达2.05 t·ha-1,黑龙江、吉林耕地SOC丢失最严重。增加秸秆还田比例,提倡免耕和人畜粪便还田,增施有机肥都有助于土壤有机碳的积累和有效地保持土壤有机碳平衡。

田间管理措施对土壤有机碳含量影响的模拟研究

利用农业生态系统生物地球化学模型(DNDC),选择6个典型的种植模式点,在特定的土壤和气候条件下运行模型,考察在其它投入条件不变的情况下,改变田间管理措施(秸秆还田、增施有机肥、改变化肥施用等)对土壤有机碳(SOC)含量影响的长期效应。研究结果表明,在众多的管理措施中,增加秸秆还田比例的固碳效应在众多的农田管理措施中体现最突出,以基本管理措施20年后有机碳含量为对照,当秸秆还田率增加到80%时,齐齐哈尔、平凉和芷江地区增加的SOC含量都在C 3 000 kg/hm2以上,北京郊区、江宁和盐亭地区每公顷则可以增加C10 000 kg以上。化肥增加SOC含量是通过增加作物还田残茬来实现的,与基本措施相比,除了华北和华东地区增施化肥使SOC含量显著增加外,其它地区均不明显。化肥施用量为本底值的50%配合秸秆还田率50%和化肥施用量为本底值的50%增施有机肥C 1 000 kg/hm2的两项措施,在各个地区都表现出比基本管理措施能存储更多的碳素,因此,在我国现在措施下,减少化肥的同时增加秸秆还田比例和增施有机肥是既增加土壤有机碳含量又减少化肥污染的"双赢"措施。

高通量测序分析PIK3CA突变型与野生型结直肠癌的肠道菌群特征

目的:采用16S rDNA二代高通量测序技术,研究PIK3CA突变型与野生型结直肠癌患者中的肠道菌群特征。方法:选取2016年12月至2017年12月华中科技大学同济医学院附属协和医院结直肠癌患者19例,采用16S rDNA高通量测序技术分析PIK3CA突变型(n=4)和PIK3CA野生型(n=15)之间肿瘤组织中微生物多样性和组成差异。结果:在门水平上,结直肠癌患者的肠道菌群主要由变形菌门、栖热菌门、放线菌门、厚壁菌门和拟杆菌门组成,占总群落的98%以上。Alpha多样性分析显示,PIK3CA突变型与野生型结直肠癌患者之间微生物多样性有显著性差异,且PIK3CA突变型患者中微生物多样性明显高于野生型。Beta多样性分析显示PIK3CA突变型与野生型结直肠癌患者的肿瘤微生物特征有显著性差异。Spearman关联网络分析结果显示,在PIK3CA野生型结直肠癌肿瘤组织中,双歧杆菌属与假单胞菌呈正相关。结论:PIK3CA突变型与野生型结直肠癌患者肿瘤组织中的微生物群落结构有显著性差异,且PIK3CA突变患者中的肠道微生物多样性更丰富。

Studies on the Situation of Soil Organic Carbon Storage in Croplands in Northeast of China

This paper aims to estimate the soil organic carbon （SOC） storage in Northeast of China, identify its balance situation and changing trends under current cropping systems, and finally put forward some strategies to keep the SOC in balance. A biogeochemical model （DNDC） for agro-ecosystem was employed to predict SOC dynamics in agricultural ecosystems at regional scale. Data on climate, soil properties, cropping systems, acreage, and management practices at county scale were collected from various sources and integrated into a GIS database to support the model runs at the regional scale. The model predicted results revealed that （1） Total SOC storage in agricultural lands in Heilongjiang, Jilin and Liaoning provinces in Northeast of China is about 1 243.48 × 10^6 t （0-30cm soil layer）, respectively occupying 58.4, 25.5 and 16.1%; （2） Under the current cultivation systems, SOC is in a situation of net loss with carbon losing at a high rate of 31.22 × 10^6 t a^-1 （respectively 59.3, 25.9 and 14.8% in Heilongjiang, Jilin and Liaoning provinces） and 2.05 t ha^-1 a^-1, the situation is more serious in Heilongjiang and Jilin provinces; and （3） Protective cultivations, such as manuring, returning more residue of crop to the field, adopting no-till, are very useful for the accumulation of SOC in these regions.

Effect of microenvironment modulation on stem cell therapy for spinal cord injury pain

Spinal cord injury （SCI） currently ranks second after mental retarda- tion among neurological disorders in terms of cost to society. Pain is a debilitating consequence of SCI related to the nature of the lesion, neurological structures damaged, and secondary pathophysiological changes of surviving tissues （Yezierski, 2005; D＇Angelo et al., 2013）.

中国新能源汽车产业协同创新网络时空演化特征分析

基于2000―2018年间新能源汽车产业发明专利数据,对新能源汽车产业创新发展阶段进行划分,以产业链视角构建新能源汽车产业协同创新网络,并以城市视角进行空间结构分析,以此探究新能源汽车产业协同创新不同发展阶段的时空演化特征。研究发现:(1)新能源汽车产业从初创期、形成期到成长期,协同创新的规模和强度均有明显上升,但在创新总体中始终占据较低比重,创新活力未完全释放,产业创新发展仍有较大空间。(2)产业链协同创新并不均衡,中游创新占据总体创新的大部分,协同创新重心由上中游协同创新向中下游协同创新过渡,创新主体呈现以企业为主、高校和研究所为辅的总体格局。(3)城市协同创新呈现规模扩大化、联系复杂化、区域一体化的特征和多点分散、局部集聚的创新格局,新能源汽车产业创新转移和演化路径已初步形成。

Surgical instruments hyalinization:Occlusion removal in minimally invasive endoscopic surgery

Minimal invasion is an important trend in surgery.However,the endoscope,as one of the key devices for monitoring the process of minimally invasive surgery,is limited by its size and working space it operates in,which result in a considerably narrow field of view.In particular,when a surgical instrument enters through the tool channel,the instrument occupies most of the area in an endoscopic image.This hampers the surgeon’s field of view and has a negative impact on the surgery.This study proposes a novel method for removing the occlusion caused by surgical instruments in endoscopic images by making foreground occlusions on endoscopic images transparent using image restoration and interframe information filling.Compared with unprocessed images,this method can provide a clearer field of view that is necessary for minimally invasive endoscopic surgeries and improve the quality of surgeries.Clinical endoscopic images are used to verify the feasibility of the proposed method,and the results show that the proposed method improves the visual effect of endoscopic images by removing surgical-instrument occlusions.This demonstrates the considerable potential of the proposed method for use in clinical applications.

硒缺乏和中国地方性心肌病:利用生物地球化学对人类健康的病理研究

1937年，在中国东北黑龙江省偏僻的农村地区首次发现一种严重的心肌病。妇女和儿童是主要的发病人群。该病的发生通常无任何征兆，导致大量的人口死亡，主要临床症状是心肌坏死，导致急性低氧、呕吐和最终在数小时内死亡。对该病最初的调查开始于20世纪30年代末至40年代，但未找到生物学感染源。该疾病即被以首次报道死亡病例的克山县来命名为克山病。