Abstract:

In order to enhance the accuracy of current large language model (LLM) in generating answers using retrieval documents, a retrieval-augmented generation method based on domain knowledge was proposed. Firstly, during the retrieval process, the first layer of sparse retrieval was conducted using both the question and domain knowledge, providing a domain-specific dataset for subsequent dense retrieval. Secondly, in the generation process, a zero-shot learning method was employed to concatenate domain knowledge before or after the question, and combined it with the retrieved documents to input into the large language model. Finally, extensive experiments were conducted on datasets in the medical and legal domains using ChatGLM2-6B and Baichuan2-7B-chat, and performance evaluations were conducted. The results indicate that the retrieval-augmented generation method based on domain knowledge can effectively improve the domain relevance of the answers generated by large language models, and the zero-shot learning method outperforms the fine-tuning method. When the zero-shot learning method is used, the sparse retrieval incorporating domain knowledge and the method of placing domain knowledge before the question achieve the best improvement on ChatGLM2-6B, with ROUGE-1, ROUGE-2 and ROUGE-L scores increasing by 3.82, 1.68 and 4.32 percentage points respectively compared to the baseline method. The proposed method can enhance the accuracy of the answers generated by large language models and provide an important reference for the research and application of open-domain question answering.

Abstract:

To address the issue of insufficient overall performance of traditional machine learning algorithms in preterm birth prediction, an innovative preterm birth prediction method based on Stacking model was proposed. Firstly, during the data preprocessing stage, an under-sampling technique was applied to balance the distribution of positive and negative samples, and numerical differences between variables were eliminated through data standardization. Secondly, feature selection was carried out by carefully analyzing the correlations between features and assessing their importance scores. Then, in the construction of the Stacking model, the Pearson correlation coefficient was calculated among the prediction results of different machine learning algorithms, and this analysis was used to adjust both the type and number of base classifiers. Finally, a comprehensive evaluation of the preterm birth prediction method based on the Stacking model was conducted using multiple evaluation indicators, and compared and analyzed with existing methods to verify the effectiveness of the method. The results show that the proposed method achieves remarkable performance, with scores of 0.921 9 in AUC, 0.922 9 in Accuracy, 0.916 4 in F1 score, and 0.858 5 in Recall. These results significantly outperform the best performances of the 11 individual models used to build the Stacking model, and the overall performance is better than the existing research methods. The proposed method can effectively identify high-risk individuals for preterm birth in early pregnancy, providing strong support for early intervention in early pregnanly.

Abstract:

To provide effective research methods for the seismic performance study of fully cast-in-place concrete exterior walls, a refined finite element modeling approach was studied based on previous seismic performance tests. Established a simplified equivalent bracing model for concrete infilled walls suitable for overall structural analysis, proposed methods for determining the location and configuration of diagonal bracing in infilled walls with openings, as well as for calculating the width and thickness of the equivalent diagonal bracing. The research results show that the damage pattern of the fully cast-in-place concrete exterior wall, as well as the hysteresis curve, stiffness, and bearing capacity characteristics derived from the refined finite element analysis, are in good agreement with the experimental results. Therefore, this model effectively reflects the mechanical performance of the test specimens. The results obtained from the simplified analysis model are also in close agreement with the experimental data. While it significantly enhances computational efficiency, the model still maintains high accuracy. The refined and simplified finite element models proposed in this study can serve as references for the finite element analysis of the fully cast-in-place concrete exterior walls at both the component level and the overall structure level.

Abstract:

In order to clarify the durability of iron tailings concrete under complex environment, the damage characteristics of iron tailings concrete under the coupling action of freeze-thaw cycle and sulfate erosion were studied. A freeze-thaw cycle test was carried out on the prepared iron tailings aggregate concrete in 5% (mass fraction, the same below) Na₂SO₄ solution to analyze the changes of mass loss, relative dynamic elastic modulus and compressive strength loss. Combined with damage mechanics, the degradation process of iron tailings concrete under coupling action was studied with ultrasonic wave velocity as damage variable, and a compacted model of iron tailings concrete was established by analyzing the relationship between ultrasonic wave velocity, elastic modulus and porosity. The results indicate that the mass of iron tailings concrete shows a phased increase after 20 cycles, followed by a decreasing trend. The relative dynamic elastic modulus and compressive strength decrease at first fast, then slow and then fast. Compressive strength loss is positively correlated with concrete damage degree, and ultrasonic wave velocity, elastic modulus and porosity are inversely proportional. Under the coupling action of freeze-thaw cycle and sulfate erosion, the deterioration rate of iron tailings concrete is the fastest. This study can provide reference value for the application of iron tailings concrete in complex cold environment.

Abstract:

In order to better improve the seismic performance of the double-steel concrete composite shear wall, a new LYP160 low-yield point corrugated double-steel plate was proposed to replace the flat steel plate in the composite shear wall structure, and 12 groups of specimens were designed with concrete strength (C30, C40, C50 and C60) and medium and low shear span ratios (2.0, 1.5 and 1.0) as the main parameters, including 6 groups of ordinary steel specimens and 6 groups of low-yield steel specimens. The finite element software was used to establish a new LYP160 low-yield point corrugated double-steel plate composite shear wall structure model, and by drawing hysteretic curves and skeleton curves, the seismic performance of 12 groups of specimens, including their bearing capacity and ductility, stiffness degradation and energy dissipation capacity was analyzed. The results show that: 1) With the increase of concrete strength, the bearing capacity of ordinary steel specimens and steel specimens with low-yield point increases, the ductility decreases to a certain extent, and the energy dissipation capacity basically does not change. Under the same concrete strength, the ductility of steel with low-yield point is better than that of ordinary steel. 2) With the decrease of the shear-span ratio, the bearing capacity of ordinary steel specimens and low-yield point steel specimens increases, and the ductility decreases slightly. Under the same shear-span ratio, the ductility of steel with low-yield point is increased by 70.83% compared with that of ordinary steel. The study proves that the bearing capacity, ductility, stiffness degradation and energy dissipation capacity of LYP160 low-yield point steel corrugated double-steel plate concrete composite shear wall are significantly improved compared with ordinary specimens, and have good seismic performance, which can provide theoretical reference for the application of LYP160 low-yield point steel corrugated double-steel plate concrete composite shear wall.

Abstract:

In order to solve the corrosion problem of concrete reinforcement under harsh environment, six new corrosion inhibitors ZS1—ZS6 were synthesized by condensation of 1,4-phenylene diisocyanate or 1,4-phenylene diisothiocyanate and compound (I). The orthogonal experimental method was used to optimize the synthesis process conditions; The corrosion resistance performance of ZS1-ZS6 was tested by linear polarization and AC impedance method, and the optimal corrosion inhibitor was selected; The influence of corrosion inhibitor on the performance of concrete was tested according to the national standard method, and weight loss rate and corrosion inhibition rate of steel bars were tested under different NaCl concentrations according to ASTM G31-72(2004) method. The results show that the optimum preparation conditions of ZS1-ZS6 are as follows: the reaction temperature of 130 ℃, the molar ratio of 1∶1.3 between 1,4-phenylene diisocyanate and diethylene triamine, and the reaction time of 24 hours; Under the optimum conditions, the yield of ZS1-ZS6 reaches 95.7%~97.2%; ZS1-ZS6 all have good anti-rust performance, with ZS5 being the best. The Cl-diffusion coefficient and carbonization depth of the benchmark concrete specimens doped with ZS5 are greatly reduced, and the compressive strength, flexion strength and slump of concrete have little change before and after mixing with ZS5, indicating good compatibility with the concrete, which is beneficial for construction. After soaking carbon steel in a 3.5% NaCl corrosion medium containing ZS5 for 90 days, the radius of the bulk resistance curve still has an increasing trend, the weight loss rate of steel bars is low, the corrosion inhibition rate is high, and the rust resistance durability is good. ZS5 can effectively prevent the corrosion of concrete reinforcement, significantly improve the durability of concrete, and can be widely used in the construction of buildings in corrosive environment.

Abstract:

In order to further explore the structural dynamic response and damage status of the upper tower subway station and promote the development of the TOD (transit-oriented development) model system oriented by public transportation, the seismic vulnerability analysis of the upper tower subway station structure in the TOD model was carried out. Taking an urban complex project in Beijing as the research background, a nonlinear analysis model of soil-structure interaction under different site types was established by considering the influence of site types, input ground motion characteristics and other factors. A seismic performance evaluation index range of the upper tower subway station structure in TOD mode was proposed and its seismic vulnerability curve was determined, and then the exceedance probability under different damage states was obtained. The results show that the corresponding seismic performance index ranges of the upper tower subway station structure under the five damage states of basically intact, slight damage, moderate damage, severe damage and collapse are [0, 0.136%], (0.136%, 0.324%], (0.324%, 0.664%], (0.664%, 1.122%] and (1.122%, +∞), respectively. The near-field pulse-type ground motion has a greater impact on the ground motion of the structure under the Class Ⅱ site, while the far-field long-period ground motion has a greater impact on the structure under the Class Ⅲ site. Compared with near-field pulse-type ground motion and ordinary ground motion, far-field long-period ground motion is more sensitive to site category. The ground motion characteristics and site types have a significant impact on the dynamic response of the upper tower subway station structure under the TOD mode. Compared with the site type Ⅱ, the ground motion characteristics of the site type Ⅲ have a more significant impact on the structure and the structure is more vulnerable to earthquake damage. The established seismic vulnerability curve and seismic damage probability table can effectively evaluate the seismic performance of the upper tower subway station in TOD mode. The research results can provide valuable reference for the seismic performance evaluation of similar underground structures.

Abstract:

To meet the requirements for long-term monitoring of hazardous gases in environmental monitoring systems, a wireless gas sensor with a low-power operation strategy was designed. The sensor integrated detection modules of methane, carbon monoxide, and carbon dioxide concentrations, with STM32L071CBT6 as the core microprocessor for data acquisition, processing, and storage. A LoRa wireless communication module was employed to transmit monitoring data to the industrial ring network. On this basis, low-power operation strategies and energy management mechanisms were proposed, and experimental verification was conducted on the wireless gas sensor. The results show that the sensor can monitor the concentrations of methane, carbon monoxide, and carbon dioxide in real-time and accurately, and the detection errors are within the allowable error range of the sensitive components; Based on a 6 000 mA·h battery capacity, the implementation of low-power operation strategies and Autosleep power management mechanism extends the monitoring duration to 142.9 days, representing a 378% increase compared to continuous operation mode. The designed wireless gas sensor demonstrates significant application value with competitive performance indicators, providing theoretical reference and practical guidance for intelligent environmental monitoring systems and wireless sensor design.

Abstract:

To improve the safety of electromagnetic sensitive equipment in the carriage in the complex electromagnetic environment, a high-altitude electromagnetic pulse (HEMP) was used as the excitation source, and the electric field-circuit coupling method was used to analyze the electric field strength and induced current of the PCB inside the power supply chassis containing a DC/DC convert in the freight high-speed rail carriage. Firstly, the simulation model of the electric field environment of the freight high-speed rail was established in the electromagnetic simulation software; Secondly, the chassis was placed at different positions inside the carriages, and the HEMP was used to irradiate the carriages from both the upper and side directions. The finite integration method (FIT) was used to predict the electric field distribution inside the carriages under the irradiation of the HEMP and to calculate the strength of the induced electric field inside the computer chassis; Then, the shielding effectiveness of the aluminum alloy material of the chassis in the range of 30~300 MHz was analyzed using the flange coaxial device method. Finally, the electric field strength of the PCB circuit board inside the chassis and the induced current were obtained using the field-circuit coupling method. The results show that for HEMP with a peak electric field of 50 kV/m, the electric field intensity near the window in the middle of the compartment is higher when irradiated on the side of the compartment at a horizontal distance of 30 km from the nuclear explosion point; 3A21 aluminum alloy sample chassis can effectively inhibit the electric field interference; The peak induced current on the PCB circuit board inside the chassis is 1.9 mA, which is in line with the requirements of GB 17625.1—2022 standard; When the peak value of electric field intensity on the PCB circuit board inside the chassis is 270 V/m, the PCB circuit works normally without deviating from the specified index value, meeting the requirements of RS103 electric field radiation sensitivity of GJB 151B—2013 standard. The research results can provide a basis for the electromagnetic protection of high-speed rail freight transportation under HEMP irradiation conditions.

Abstract:

To prevent safety accidents and improve the safety of in-service storage tanks with defects, the stress intensity factors of cracks of different sizes and locations in tanks with crack defects were studied. Taking the storage tank with a semi-elliptic surface crack under internal pressure as the research object, the influence of different crack length c, the ratio of crack depth to tank thickness (a/t), and the location of the crack on the maximum value K_Ⅰ,max of the stress intensity factor at the crack tip was studied by using the interaction integration method. The results show that when the crack is located in the cylinder, K_Ⅰ,max> increases with the increase of crack length and the ratio of crack depth to tank thickness, and the growth rate is not fixed; When the crack is located in the elliptical head, K_Ⅰ,max decreases with the increase of the angle θ between the geometric center of the crack surface and the connecting line of the elliptical head center and the long axis of the elliptical head, and increases with the increase of the crack length; When the crack is located in the high stress area near the opening, the change rule of K_Ⅰ,max with the crack length is consistent with that of the cylinder; When the crack length is greater than the crack depth, K_Ⅰ,max appears in the middle of the crack leading edge, and vice versa. The research results have a certain reference significance for the safety evaluation and inspection rules of in-service defective storage tanks and other pressure vessels.

Abstract:

In order to achieve non-contact visual sensing of the blunt impact field for ballistic protection devices, a self-responsive bionic target was established. Mechanoluminescence material (ZnS∶Cu), was used as the force-sensitive material and compounded with silicone rubber to prepare a responsive bionic skin. This skin was then combined with the bionic adipose prepared from Kraton polymer (hereinafter referred to as Kraton-based bionic adipose) to form the self-responsive bionic target. Quasi-static mechanical tests were carried out on the self-responsive bionic skin and Kraton-based bionic adipose, and their mechanical properties were compared with those of biological skin and biological adipose. Finally, the impact characteristics of the self-responsive bionic target were studied. The results indicate that the elastic modulus of the designed and synthesized bionic skin （ZnS∶Cu-5，ZnS∶Cu-10） at a strain rate of 0.10 s^-1 differs from that of the skin of the human forearm by 5.33% and 1.33% respectively within the low strain region. The elastic modulus of the Kraton-based bionic adipose is close to that of the adipose tissue of the sheep′s hip region, with a deviation of 5.53%. This demonstrates the rationality of using the "mechanoluminescence material-silicone rubber-Kraton-based polymer" as the bionic target. The target exhibits a significant mechanoluminescence response under impact loading, with the luminescent intensity linearly correlated with the peak value of the shock wave. When the impact air pressure is 0.3 MPa, the relative error of the initial peak pressure of the obtained blunt impact field shock wave is 13.7%, indicating high accuracy. This shows that the self-responsive bionic target has great potential in real-time visual testing of shock wave fields experienced by soft tissues. The research provides a new idea for ballistic terminal testing methods.

Abstract:

In order to study the dynamic response and stability of transmission tower foundations in karst geological regions under earthquake action, the finite element numerical simulation method was used to study the changes in acceleration response, settlement, stress, and damage levels of transmission tower foundations under different spectral characteristics of seismic waves, peak acceleration of seismic waves, sizes of karst caves, and different vertical distances from the transmission tower foundations. The results show that the acceleration response of the top of the transmission tower foundation under earthquake actions has a significant amplification effect; With the increase of peak acceleration, the settlement value of the transmission tower foundation continues to increase; With the increase of the diameter of the karst cave, the change trend of the foundation settlement conforms to the exponential function distribution; The influence of karst caves on the settlement of the transmission tower foundations decreases with the increase of distance and the settlement fluctuation amplitude is related to the vertical distance between the karst cave and the transmission tower foundation; There is stress concentration at the intersection of the corner of the transmission tower foundation and it is a vulnerable area to earthquake damage. When the vertical distance between the karst cave and the tower foundation is greater than 3 meters, the inclination is less than 5‰ , which meets the settlement limit requirement. However, when the vertical distance between the karst cave and the tower foundation is less than 3 meters, instability is prone to occur. In practical engineering design, attention should be paid to and prevention measure should be taken. The research results can provide reference for the stability assessment of tower foundations under earthquake action, as well as for their seismic design, construction, and maintenance.

Abstract:

为了提高小型随车起重机出厂起重性能测试的方便性和高效性。依照随车起重机自身的车载吊臂工作性能,设计了一种基于PLC控制的液压试验平台检测设备。根据随车起重机在工作中需要完成的动作和性能参数要求,设计了一套电-液控制系统,描述了液压试验平台结合多传感器实时采集数据与PLC进行RS485通信,并对液压系统中电磁阀电信号进行调控,以此检测随车起重机起重性能状况。结果表明:该液压试验台经对2 t和3.5 t小型随车起重机进行起重性能测试的结果符合厂家所设计的起重机性能参数范围。该套液压检测设备采用触摸屏进行人机交互,界面操作简单、系统运行平稳,既保证了性能检测的准确度,又可以有效缩短检测周期,提高了出厂性能检测的效率。

Abstract:

为了夯实近代童装文物复原研究的理论基础,以河北永清服装博物馆内一件大红色提花绸儿童夹袄为研究对象,对文物的纤维色彩、形制结构和面料组织结构进行深入研究。采用显微观察、红外光谱、紫外可见光谱、薄层色谱等方法对文物的纤维与染料进行检测鉴别,同时用平面接触式测量法获取文物数据,密度镜测量法分析面料组织,并对文物结构图和组织图进行复原。结果表式测量法获取文物数据,密度镜测量法分析面料组织,并对文物结构图和组织图进行复原。结果表明:该夹袄整体采用丝纤维制成,多为富贵儿童穿着;红色衣身为偶氮类染料染色,缘饰为靛系染料染色,说明近代已使用合成染料,且色泽艳丽;服装结构为盘扣缘饰(满族特色)和交领绑带(汉族特色)并用,为满汉融合背景下的特殊形制。研究结果可使近代童装的理论研究更加完善,为近代童装的复原研究提供方法和科学依据。

Abstract:

In order to analyze haze change regularity and the origin of the haze weather and provide technical support for its prevention, the correlation between the haze and meteorological condition and pollutants concentration are discussed based on the surface meteorological observation data and the pollutants concentration monitoring data from the step station of Shijiazhuang environmental monitoring center. It is proved that the haze days during the 1960s is minimal; the haze days rises sharply during the initial stages for reform and opening-up and the 1990s; the haze days obviously decreases after the 2000s.The haze occurs more frequently in autumn (20.5%) and winter (53.5%), and less in spring(15.2%) and summer(10.8%). Quiet wind, lower humidity and continuous no-rain days are the important causes of the haze. The mass concentration change regularity of SO₂, NO_<i>x, PM2.5 and PM10 (the correlation coefficients are 78.4%,70.9%,77.3% and 73.8%, respectively) is coherence with the haze days of Shijiazhuang City. Their mass concentration is obviously higher in haze days than in the normal days. Their mass concentration is highest in winter, lower in autumn and lowest in summer.

Abstract:

Antimony-doped tin dioxide is an excellent catalyst, which has good electrical conductivity and high temperature stability. The sol-gel method is used to prepare ATO nanopowders, and their structure characterization and performance analysis are also conducted. Stable tin and antimony citrate complexes solution is obtained from the starting materials metal tin and antimony trioxide. The solution undergoes sol-gel transformtion when acetonitrile is added dropwise. Antimony doped tin oxide nanoparticles are obtained with the washed gel heat-treated at different temperatures. The antimony doped tin oxide nanoparticles exhibit shrinking crystallite size, increasing specific surface area and tin oxide lattice parameters changing with the rise of antimony doping content. The crystalline size increases, while speciflc surface area decreases with the increase of annealing temperature. The particle crystallinity shows a decrease tendency for the high antimony doping level with increasing temperatures.

Abstract:

Po lyv inyl Alcoho l ( PVA) is w ater??soluble polymer , and no n??t ox ic t o human body. It has go od bio??compat ibility, so PVA develops rapidly in medical t reatment . Develo pment in the study o f PVA, including adv ance of PVA hydro??gel in eye, wo und dr essing s and art ificial car tilag e, and application o f PVA member in medicine and so o n are intro duced in det ail in t he re?? v iew

Abstract:

This paper introduced the widespread use of acetonitrile as a good organic solvent and an important raw material in the field of chemical industry, medicine and so on, and gave a summary report about some direct and indirect synthesis methods in regard of the properties of acetonitrile. Then the potential application prospect and synthetic method of acetonitrile were put forward.

Abstract:

To provide a foundation for further study on Huanglianwendan decoction and its possible clinical applications,this paper reviewed the recent 10years'' literatures about its clinical studies, including those on treating psychosis, digestive system disease, decompensation disease, chronic renal failure disease, curdiovascular, and otorhinolaryngology disease.

Abstract:

Po lymer nano par ticles as drug car rier sy st ems is a new kind o f drug deliver y sy stem. It is easy to get to site- specific throug h bio film bar rier fo r the nanoparticles. Po lymer nanopart icles hav e new characterist ics fo r multifo rmity of polymeric mater ial, so po lymer nano par ticles em ployed as drug carr iers hav e att racted attention. In this r ev iew , the tw o prepa rativ e methods for dispersio n of the pr eformed po lymer s and polymerization o f mo nomers are ex pounded, t he measur ing metho d of particles d-i ameter , modality, moleculer w eight, Zeta po tent ial and thermic perfo rmance are investig ated, and the applicatio ns are discussed. At last are the sug g estions o n development t rend fo r polymer nanoparticles as drug car rier

Abstract:

This article summarized the physical chemistry and biological treatment technologies of high salinity organic wastewater and introduced combined processes of biological and other treatments. Halophilic bacteria and salt-tolerant microzyme have wide practicability in the treatment of highsalinity wastewater.

Abstract:

This paper investigated the feasibility of detecting Sudan Red in foods with thin layer chromatography, and compared the result of Sudan Red separation with high-effect silica gel G plates (HPSGG) and the result of it with polyamide plates. It is found that HPSGG has more advantages over polyamide plates in separating Sudan Red. HPSGG gives high detection sensitivity, up to 0.3mg/ kg, fast analysis and clear separation. Polyamide plates needs 40minutes while high-effect silica gel G plates needs only 5～10minutes. The Sudan pigments and other interference pigments such as pepper pigments,can be completely separated. The method can be applied to rapidly detect Sudan Red illegally added in foods such as chilli products and hamburgers.

Abstract:

This paper summarized the methods of the measurement of total nitrogen, the measurement of total phosphorus and the combined measurement.It compared the merits and demerits of these methods and put forward the development trend of the measurement methods.

Abstract:

This paper introduced the production process and application of pentaerythritol and analyzed its market situation.Then the paper pointed out the problems unsettled and gave some advices.

Abstract:

Face recognition is a technique used for identify identity by analyzing face images and distilling effective recognition information from face images. This article presented an arithmetic of face recognition based on eigenfaces, gave the explaination of eigenface,and made a simulation of DRL face database by using program baced on OpenCV. This method recognizes and classifies face images by computing the space distance between face image and eigenfaces,and it can recognize face image quickly and exactly.

Abstract:

A br ief intro ductio n to DNP3. 0 ( Distr ibuted Netwo rk Pr oto co l 3. 0) is presented at this paper to gether w ith an explanation o f t he architecture and functio nality pr ovided by this prot ocol. An appr oach to implement the pr oto co l that ado pts the OOP and the VCL component techniques in the Delphi prog r amm ing envir onment is discussed

Abstract:

Based on sixsigma,the software process defects management model is established. The model combines the method of six sigma to provide effective solution for software process defects management. The model can get better quality and better customer satisfaction by optimizing the software development process, tracking adverse factors and eliminating defects.