Construction of all-organic low dielectric polyimide hybrids via synergistic effect between covalent organic framework and cross-linking structure

Polyimide(PI)is a promising electronic packaging material,but it remains challenging to obtain an all-organic PI hybrid film with decreased dielectric constant and loss without modifying the monomer.Herein,a series of allorganic PI hybrid films were successfully prepared by introducing the covalent organic framework(COF),which could induce the formation of the cross-linking structure in the PI matrix.Due to the synergistic effects of the COF fillers and the cross-linking structure,the PI/COF hybrid film containing 2 wt%COF exhibited the lowest dielectric constant of 2.72 and the lowest dielectric loss(tanδ)of 0.0077 at 1 MHz.It is attributed to the intrinsic low dielectric constant of COF and a large number of mesopores within the PI.Besides,the cross-linking network of PI prevents the molecular chains from stacking and improves the fraction of free volume(FFV).The molecular dynamics simulation results are well consistent with the dielectric properties data.Furthermore,the PI/COF hybrid film with 5 wt%COF showed a significant enhancement in breakdown strength,which increased to 412.8 kV/mm as compared with pure PI.In addition,the PI/COF hybrid film achieve to reduce the dielectric constant and thermal expansion coefficient(CTE).It also exhibited excellent thermal,hydrophobicity,and mechanical performance.The all-organic PI/COF hybrid films have great commercial potential as next-generation electronic packaging materials.

Effects of Combined Application of Water Retaining Agents and Organic Materials on Water Holding Characteristics of Yellow Brown Soils in Hilly Areas

[Objective] The aim was to reduce fertilizer and water losses caused by surface runoffs in rainy season and provide scientific references for soil moisture in arid season. [Method] The application proportion of complex water-holding organic materials was determined by multi-factor mixture experiment and the curve changes of soil moisture characters were tested to analyze water-holding capacity and water availability of soils. [Result] The initial moisture content of soil with different mixture proportions improved in varying degrees. For example, when water-retention agents reached 0.4% and 0.6% of soil weight, soil moisture contents were 69.0% and70.5%, respectively, which showed significant differences with the control（S0.0）. Soil dehydration terms in different treatments all extended, prolonging in the range of4.6-14 d. [Conclusion] The applications of water-retention agent and organic material would improve water-holding capacity of hills and low mountains, and initial moisture content and dehydration cycle tend to be volatile upon mixture proportion. Therefore,it is necessary to adjust soil fertility, crop species, and irrigation to meet crop demands on fertilizer and water.

Surface organic modification of Fe_3O_4 nanoparticles by silane-coupling agents

Fe3O4 nanoparticles were prepared by chemistry co-precipitation and the mean crystal size was 17.9 nm measured by XRD. After it had been treated by silane-coupling agents KH570, magnetic micro-spheres dispersed in organic medium glycol were gained and the mean size of Fe3O4 nanopowders was 33.7 nm. So it can be concluded that magnetic micro-sphere is made of a few Fe3O4 crystals. Many factors of modification were researched, such as the time of ball milling, the content of Fe3O4 and the content of KH570. The modification of Fe3O4 is relative to the time of ball milling, but the dominant function is affected by the content of Fe3O4 and KH570. When the content of Fe3O4 is known, there is a suitable content of KH570. Different content of Fe3O4 will make the different suitable content of KH570, but the range of latter is less than former, which is relative to the distribution of KH570 on Fe3O4 surface or in the solution.

Highly efficient and stable organic solar cells with SnO_(2)electron transport layer enabled by UV-curing acrylate oligomers

The interfaces between the inorganic metal oxide and organic photoactive layer are of outmost importance for efficiency and stability in organic solar cells(OSCs).Tin oxide(SnO_(2))is one of the promising candidates for the electron transport layer(ETL)in high-performance inverted OSCs.When a solution-processed SnO_(2)ETL is employed,however,the presence of interfacial defects and suboptimal interfacial contact can lower the power conversion efficiency(PCE)and operational stability of OSCs.Herein,highly efficient and stable inverted OSCs by modification of the SnO_(2)surface with ultraviolet(UV)-curable acrylate oligomers(SAR and OCS)are demonstrated.The highest PCEs of 16.6%and 17.0%are achieved in PM6:Y6-BO OSCs with the SAR and OCS,respectively,outperforming a device with a bare SnO_(2)ETL(PCE 13.8%).The remarkable enhancement of PCEs is attributed to the optimized interfacial contact,leading to mitigated surface defects.More strikingly,improved light-soaking and thermal stability strongly correlated with the interfacial defects are demonstrated for OSCs based on SnO_(2)/UV cross-linked resins compared to OSCs utilizing bare SnO_(2).We believe that UV cross-linking oligomers will play a key role as interfacial modifiers in the future fabrication of large-area and flexible OSCs with high efficiency and stability.

Study of Sorption Properties of Anion Exchangers with Long-Chained Cross-Linking Agents for Tungsten Hydrometallurgy

The macroporous anion exchangers with long-chained cross-linking agents were investigated for the tungsten recovery from salt solutions.The physical-chemical characteristics of these sorbents were studied by means of sorption-desorption experiment aswell as electron and IR-spectroscopy.The anion exchangers on the basis of macroporous copolymers of methylacrylate and divinyl-ester of diethyleneglycol or tetravinyl-ester of pentaerythritol possess the exchange capacity to tungsten 2--5 times greater than the porous anion exchangers on the basis of styrene and divinylbenzene,therefore they can be used for selective tungsten recovery from comulex salt solutions.

Effects of organic mulching on soil aggregate stability and aggregate binding agents in an urban forest in Beijing, China

Urban forest soil is often disturbed by rapid urbanization. Organic mulching is effective for improving soil quality and aggregate stability. This study evaluated how soil binding agents changed aggregate stability through organic mulching in urban forest soils. Three treatments were applied in Jiufeng National Forest Park, Beijing: (1) no organic mulch (control);(2) wood chips alone (5 cm thickness);and, (3) wood chips + wood compost (This mulch was divided into two layers, the upper layer of wood chips (2.5 cm), the lower layer wood compost (2.5 cm)). Soil samples were collected from the surface 10- cm soil layer and fraction into four aggregates. Glomalin-related soil protein and soil organic carbon were measured in bulk soil and the four aggregates. The results show that wood chips + wood compost increased the proportion of large and small macroaggregates, mean weight diameter and geometric mean diameter. The total and easily extractable glomalin-related soil protein were higher in the wood chips + wood compost. However, soil organic carbon was lower in the wood chips alone application compared to the controls and wood chips + wood compost. Easily extractable / total glomalin-related soil protein and glomalin-related soil protein / soil organic carbon ratios of wood chips alone and wood chips + wood compost had increased trend compared to the controls but did not reach significant levels (p > 0.05). Mean weight diameter and geometric mean diameter correlated positively with total and easily extractable glomalin-related soil protein but were not positively correlated with soil organic carbon, the ratios of easily extractable and total glomalin-related soil protein, and the ratios of glomalin-related soil protein and soil organic carbon. Redundancy analysis revealed that total glomalin-related soil protein was the most important driver for soil aggregate stability, especially the total glomalin-related soil protein of small macroaggregates. The results suggest that wood chips + wood compost enhanced soil aggregate stability through the increase of glomalin-related soil protein. Wood chips alone cannot enhance soil aggregate stability in urban forests in the short term.

Effect of Cross-linking Agent on Barbituric Acid-initiated Resin

To improve the tensile bond strength of denim bonding agents, the adhesion between denim and MMA resin was investigated by applying initiator systems containing 1-cyclohexyl-5-ethyl barbituric acid (CEB), copper acetyl acetonate (CAA), quaternary ammonium chloride (QAC). cupric ion, with the addition of TEGDMA, an.d pretreatment solution for denim, and an HEMA primer. The effects of a cross-linking agent on barbituric acid-initiated denim bonding resin were examined by measuring degree of conversion, molecular weight, hardness of bonding resin, and tensile bond strengths.

Degradable preformed particle gel as temporary plugging agent for low-temperature unconventional petroleum reservoirs:Effect of molecular weight of the cross-linking agent

The development of unconventional petroleum resources has gradually become an important succession for increasing oil production.However,the related engineers and researchers are paying more and more attention to the application of temporary plugging agents(TPAs)for their efficient development.TPAs can expand the stimulated reservoir volume(SRV)and facilitate the flow of oil and gas to the bottom of the well.Particle-gels used as temporary plugging agents have the characteristics of the simple injection process,good deformation,high plugging strength,and complete self-degradation performance,which have been widely applied in recent years.In this paper,five samples of DPPG polymerized by different molecular weights of cross-linking agents were prepared.In addition,infrared spectroscopy analysis,differential calorimetry scanning(DSC)analysis,static particle gel swelling and degradation performance evaluation experiments,and dynamic temporary plugging performance experiments in cores were conducted at 34°C.Results show that as the molecular weight of the cross-linking agent(at 0.01 g)in the DPPG molecule decreased from 1,000 to 200 Da,the fewer cross-linking sites of DPPG,the looser the microscopic three-dimensional mesh structure formed.The swelling ratio increased from 7 to 33 times.However,the complete degradation time increased from 40 to 210 min.Moreover,the DSC results confirmed that the higher the molecular weight of the cross-linking agent,the worse is chemical stability and the more prone it to self-degradation.DPPG samples had good temporary plugging performance in reservoir cores.DPPGs prepared by the cross-linking agent with smaller molecular weight has a stronger swelling ratio,higher gel strength,and greater plugging strength in the core permeabilities.Moreover,the degraded DPPG is less damaging to the cores.However,their slower degradation rates take a slightly longer times to reach complete degradation.The results of this paper can provide new ideas and a theoretical basis for the development of particle gel-type temporary plugging agents(TPA)with controllable degradation time in low-temperature reservoirs.It can help to expand the application range of existing DPPG reservoir conditions.

Improvements to the Fluoride Reactivation Method by Simple Organic Extraction for Retrospective Detection of Exposure to the Organophosphorus Nerve Agents in Human Plasma

A rapid and simple organic extraction method for the determination of the chemical warfare agent, isopropyl methylphosphonofluoridate (sarin, GB) in human plasma has been developed using gas chromatography-tandem mass spectrometry (GC-MS/MS). In the course of method development, several organic solvents have been screened and chloroform show a low background and increase signal to noise ratio of GB among other organic solvents. Especially, the organic extraction method of reactivated GB from the human plasma has a 30% greater recovery yield than solid-phase ex-traction (SPE). This simple extraction method was successfully applied to the trace analysis of nerve agents in human plasma in the 3rd Organisation for the Prohibition of Chemical Weapons (OPCW) confidence building exercise on biomedical sample analysis.

Lithium Recovery from Electrodes in Cellphone Batteries through the Leaching Process with Organic Agents Assisted by Ultrasound

The present work proposes a mean for recovery of metals used in current ion-lithium batteries, like lithium, cobalt and nickel, using organic agents and ultrasound instead of the more aggressive and less environment friendly method with sulfuric acid. This is especially useful in those countries that doesn’t have lithium deposits and have a growing demand of such batteries, reducing the economic loss this represents. During the process, variables such as temperature, leaching agent concentration and ultrasound frequency were modified, using concentrations of 0.5 M (molar), 1 M and 1.5 M of sodium citrate, temperatures of 25°C, 55°C and 60°C and also ultrasound frequencies of 20 KHz, 30 KHz and 40 KHz. It was found that the best combination of these variables that yielded the most quantity of the desired metal was 0.5 M concentration for both lithium and nickel, while using 60°C and no ultrasound with Li and 55°C and 40 KHz for Ni. For Co the best variables discovered were 1.5 molar concentration, 60°C and 40 KHz.

Self Organization Map for Clustering and Classification in the Ecology of Agent Organizations

Development of computational agent organizations or “societies” has become the domiant computing paradigm in the arena of Distributed Artificial Intelligence, and many foreseeable future applications need agent organizations, in which diversified agents cooperate in a distributed manner, forming teams. In such scenarios, the agents would need to know each other in order to facilitate the interactions. Moreover, agents in such an environment are not statically defined in advance but they can adaptively enter and leave an organization. This begs the question of how agents locate each other in order to cooperate in achieving organizational goals. Locating agents is a quite challenging task, especially in organizations that involve a large number of agents and where the resource avaiability is intermittent. The authors explore here an approach based on self organization map (SOM) which will serve as a clustering method in the light of the knowledge gathered about various agents. The approach begins by categorizing agents using a selected set of agent properties. These categories are used to derive various ranks and a distance matrix. The SOM algorithm uses this matrix as input to obtain clusters of agents. These clusters reduce the search space, resulting in a relatively short agent search time.

Study on the Activation Effect of Fermented Organic Fertilizers on Selenium in the Soil of Southern Dragon Fruit Orchards

[Objectives]This study was conducted to explore the effects of using fermented organic fertilizers such as cow manure on the activity of selenium in the soil.[Methods]The project team applied the organic fertilizer prepared by fermenting cow manure and other raw materials to activate selenium in the soil at two dragon fruit orchard bases in Shilong Town,Guiping City and Dingdang Town,Long an County,and carried out many years of experiments.[Results]The contents of available selenium in the two experimental orchards in Shilong Town and Dingdang Town increased by 10%and 5%,respectively,and the selenium contents in dragon fruit increased by 228.6%and 200.0%,respectively.[Conclusions]The application of fermented organic fertilizers such as cow manure can increase available selenium content in the soil,thereby increasing the selenium content of dragon fruit.

Assessment of strength development in cement-admixed artificial organic soil with GX07

To explore the stabilization effect of stabilizing agent GX07 on treating organic soil and the influence of organic matter on the strength development of stabilized soil,artificial organic soil with various organic matter content was obtained by adding different amounts of fulvic acid into non-organic clay,and then liquid-plastic limit tests were carried out on the artificial organic soil.Meanwhile,unconfined compressive strength(UCS) tests were performed on cement-only soil and composite stabilized soil,respectively.The test results indicate that the plastic limit of soil samples increases linearly,and the liquid limit increases exponentially as the organic matter content increases.The strength of stabilized soil is well correlated with the organic matter content,cement content,stabilizing agent content and curing time.When the organic matter content is 6%,as the cement content varies in the range of 10%-20%,the strength of cement-only soil increases from 88.5 to 280.8 kPa.Once 12.6% GX07 is added into the mix,the strength of stabilized soil is 4.93 times compared with that of cement-only soil.GX07 can obviously improve the strength of cemented-soil and has a good economic applicability.A strength model is proposed to predict strength development.

Preparation of Controllable Cross-Linking Polyethylene Foaming Materials and Their Properties

In order to prepare the polyethylene materials with controlling properties,we developed two kinds of controllable cross-linking polyethylene foaming system.2,5-dimethyl-2,5-bis (tert-butyl peroxy) hexane was used as cross-linking agent and TEMPO as cross-linking inhibitor,azodicarbonamide (AC) was used as foaming agent and citric acid as foaming promoter.The density,expansion ratio,cellular structure and mechanical property of these two kinds of controllable materials were studied.Experimental results show that,properties of these two kinds of materials appear similar trend:cellular size and expansion ratio are enlarged with the amount of cross-linking inhibitor or foaming promoter increasing,while density and mechanical strength appear decreasing trend.Through comparing those two material systems’ properties,cross-linking polyethelene foaming system with citric acid as foaming promoter has better properties.

Discrete decision model and multi-agent simulation of the Liang Zong two-chain hierarchical organization in a complex project

Different from the organization structure of complex projects in Western countries, the Liang Zong hierarchical organization structure of complex projects in China has two different chains, the chief-engineer chain and the general-director chain,to handle the trade-off between technical and management decisions. However, previous works on organization search have mainly focused on the single-chain hierarchical organization in which all decisions are regarded as homogeneous. The heterogeneity and the interdependency between technical decisions and management decisions have been neglected. A two-chain hierarchical organization structure mapped from a real complex project is constructed. Then, a discrete decision model for a Liang Zong two-chain hierarchical organization in an NK model framework is proposed. This model proves that this kind of organization structure can reduce the search space by a large amount and that the search process should reach a final stable state more quickly. For a more complicated decision mechanism, a multi-agent simulation based on the above NK model is used to explore the effect of the two-chain organization structure on the speed, stability, and performance of the search process. The results provide three insights into how, compared with the single-chain hierarchical organization, the two-chain organization can improve the search process: it can reduce the number of iterations efficiently; the search is more stable because the search space is a smoother hill-like fitness landscape; in general, the search performance can be improved.However, when the organization structure is very complicated, the performance of a two-chain organization is inferior to that of a single-chain organization. These findings about the efficiency of the unique Chinese-style organization structure can be used to guide organization design for complex projects.

功能菌剂偶联有机肥强化秸秆还田

设置添加秸秆降解菌剂(MC)、有机肥(OF)、菌肥联用(MC+OF)和空白对照(CK) 4个处理,进行了为期120d的还田实验,分析不同处理对还田秸秆降解速度、土壤理化性质及土壤微生态的影响.结果表明,MC+OF处理的秸秆降解和腐殖化效果最佳.还田120d时,MC+OF组半纤维、纤维素、木质素降解率和秸秆失重率分别较其他处理高2.87%~11.78%、3.20%~10.59%、6.00%~32.97%和9.49%~26.77%(P<0.05),腐殖质含量最高,达70.39g/kg;土壤总有机碳和溶解性有机碳分别较初始增加33.39%和62.00%,土壤总养分(氮磷钾)相对初始增加134.21mg/kg.此外,秸秆降解菌剂接种后其中的Aspergillus能够在秸秆还田过程中成为优势菌属,并诱导了Alcaligenes、Ensifer和Brevundimonas等具有木质纤维素降解功能的土著微生物显著富集;菌肥联用还提高土壤中蔗糖酶、脲酶和中性磷酸酶等碳、氮和磷转化的关键酶活力,降低了病理营养型真菌总量,提升了土壤品质.综上所述,MC+OF是解决还田秸秆降解难、资源循环受阻的有效手段,对降低环境污染风险和实现生态环境可持续发展具有重要意义.

肺移植受者术后医院感染病原学特点及药敏分析:一项单中心5年回顾性调查研究

目的分析单中心近5年肺移植受者术后医院感染特点及药物敏感性。方法选取无锡市人民医院2019年1月至2023年12月724例肺移植受者,依据医院感染判定原则,回顾性分析肺移植受者医院感染情况及感染部位,对医院感染病原菌分布及其药敏试验状况进行分析。结果724例肺移植受者中,275例发生医院感染,感染率为38.0%。感染例次率由2019年的54.2%降低至2023年的22.8%,呈逐年下降趋势(Z=30.98,P<0.001)。感染部位主要为下呼吸道,占73.6%。感染病原菌以革兰阴性菌为主,前4位为鲍曼不动杆菌(37.1%)、铜绿假单胞菌(17.3%)、肺炎克雷伯菌(13.7%)和嗜麦芽窄食单胞菌(13.4%),对亚胺培南的耐药率分别为89%、53%、58%和100%。革兰阳性菌以金黄色葡萄球菌为主(3.6%),对苯唑西林的耐药率为67%。结论近5年肺移植受者的医院感染呈下降趋势,主要以下呼吸道感染为主,感染病原菌主要为鲍曼不动杆菌、铜绿假单胞菌、肺炎克雷伯菌,对亚胺培南的耐药率均较高。

面向Agent程序设计的研究

面向Agent程序设计(agent-oriented programming,简称AOP)基于多Agent系统的抽象和思想、借助于Agent理论和技术来支持软件系统的构造与实现,其程序设计思想、软件模型、基础理论和语言设施有别于现有主流程序设计技术,如OOP,代表了一种新颖的程序设计范型.由于多Agent系统被视为支持开放环境下复杂软件系统开发的一种新颖、有效的技术手段,因而近年来AOP受到人工智能、软件工程和分布计算等领域研究学者和工程实践人员的高度关注,并在过去20年取得了重要进展.但是,无论在应对复杂多Agent系统开发方面,还是在大规模工业化应用等方面,AOP的研究与实践都面临着严峻的挑战.作为一种程序设计范型,AOP研究需要在交叉其他学科知识(如人工智能)的基础上,充分借鉴软件工程以及已有程序设计范型的原理、原则和成功实践,从而推动技术走向成熟并为广大工程实践人员所接受.通过对AOP研究历程的系统介绍,从软件工程的视点考虑MAS程序设计的不同层次,综述AOP在程序设计抽象与模型、机制与理论、语言与设施和支撑平台这4个方面的研究成果,展示不同时期AOP研究关注点的变化以及发展趋势,分析当前AOP研究与实践存在的问题和面临的挑战,并展望进一步的研究.

面向结构的Agent组织形成和演化机制

基于 Agent组织的多 Agent问题求解可以大大降低求解难度和交互复杂性 .其中 Agent组织的形成和演化是基于 Agent计算和合作的关键 .给出了面向结构的组织形成和演化机制 ,解决了麻木性和灵活性差问题 ,保证了 Agent的效用理性和个性倾向 ,刻画了演化所满足的性质 ,改进了 Shehory,Kraus,Glaser等的组织形成和演化方法 .