Controlling Reactivity of Palladium Amides for Selective Carbonylation towards Urea and Oxamide Derivatives

Carbonylation reactions,crucial for carbonyl group incorporation,struggle with the inherent complexity of achieving selective mono-or double-carbonylation on single substrates,often due to competing reaction pathways.Herein,our study introduces a strategy employing palladium amides,harnessing their unique reactivity control,to direct the selective carbonylation of amines for the targeted synthesis of urea and oxamide derivatives.The palladium amide structure was elucidated using single-crystal X-ray diffraction.Controlled experiments and cyclic voltammetry studies further elucidate that the oxidation of palladium amide or its insertion into a carbonyl group diverges into distinct pathways.By employing sodium percarbonate as an eco-friendly oxidant and base,we have successfully constructed a switchable carbonylation system co-catalyzed by palladium and iodide under room temperature.The utilizing strategy in this study not only facilitates effective control over reaction selectivity but also mitigates the risk of explosions,a critical safety concern in traditional carbonylation methods.

Control of reactive dividing wall column for selective hydrogenation and separation of C3 stream

In our previous work, the reactive dividing wall column(RDWC) was proposed and proved to be effective for selective hydrogenation and separation of C3 stream. In the present paper, the dynamics and control of the proposed RDWC are investigated. Four control structures including composition and temperature controls are proposed. The feed forward controllers are employed in the four control strategies to shorten the dynamic response time, reduce the maximum deviations and offer an immediate adjustment. The control structures are compared by applying them into the RDWC system with 20% disturbances in both the feed flow rate and the feed compositions, and the results are discussed.

Tuning the selectivity of natural oils and fatty acids/esters deoxygenation to biofuels and fatty alcohols:A review

The chemical transformation of natural oils provides alternatives to limited fossil fuels and produces compounds with added value for the chemical industries.The selective deoxygenation of natural oils to diesel-ranged hydrocarbons,bio-jet fuels,or fatty alcohols with controllable selectivity is especially attractive in natural oil feedstock biorefineries.This review presents recent progress in catalytic deoxygenation of natural oils or related model compounds(e.g.,fatty acids)to renewable liquid fuels(green diesel and bio-jet fuels)and valuable fatty alcohols(unsaturated and saturated fatty alcohols).Besides,it discusses and compares the existing and potential strategies to control the product selectivity over heterogeneous catalysts.Most research conducted and reviewed has only addressed the production of one category;therefore,a new integrative vision exploring how to direct the process toward fuel and/or chemicals is urgently needed.Thus,work conducted to date addressing the development of new catalysts and studying the influence of the reaction parameters(e.g.,temperature,time and hydrogen pressure)is summarized and critically discussed from a green and sustainable perspective using efficiency indicators(e.g.,yields,selectivity,turnover frequencies and catalysts lifetime).Special attention has been given to the chemical transformations occurring to identify key descriptors to tune the selectivity toward target products by manipulating the reaction conditions and the structures of the catalysts.Finally,the challenges and future research goals to develop novel and holistic natural oil biorefineries are proposed.As a result,this critical review provides the readership with appropriate information to selectively control the transformation of natural oils into either biofuels and/or value-added chemicals.This new flexible vision can help pave the wave to suit the present and future market needs.

Deducing Complete Selection Rule Set for Driver Nodes to Guarantee Network’s Structural Controllability

Structural controllability is critical for operating and controlling large-scale complex networks. In real applications, for a given network, it is always desirable to have more selections for driver nodes which make the network structurally controllable. Different from the works in complex network field where structural controllability is often used to explore the emergence properties of complex networks at a macro level,in this paper, we investigate it for control design purpose at the application level and focus on describing and obtaining the solution space for all selections of driver nodes to guarantee structural controllability. In accord with practical applications,we define the complete selection rule set as the solution space which is composed of a series of selection rules expressed by intuitive algebraic forms. It explicitly indicates which nodes must be controlled and how many nodes need to be controlled in a node set and thus is particularly helpful for freely selecting driver nodes. Based on two algebraic criteria of structural controllability, we separately develop an input-connectivity algorithm and a relevancy algorithm to deduce selection rules for driver nodes. In order to reduce the computational complexity,we propose a pretreatment algorithm to reduce the scale of network's structural matrix efficiently, and a rearrangement algorithm to partition the matrix into several smaller ones. A general procedure is proposed to get the complete selection rule set for driver nodes which guarantee network's structural controllability. Simulation tests with efficiency analysis of the proposed algorithms are given and the result of applying the proposed procedure to some real networks is also shown, and these all indicate the validity of the proposed procedure.

Type selection and maintenance of the control system of large-scale air separation units

Based on the practice of Baosteel＇ s 60000 m3/h air separation unit （ASU） ,which is the first domestically- integrated unit of such a scale, this paper studies the principles of type selection of the distribution control system （DCS）. It discusses the design of the unit＇s control system,which involves a compressor system,a purification system （molecular sieving）, a turbo expansion system and an air separation system. The final part of the paper discusses the maintenance and future development of the ASU control system at Baosteel.

Joint power control and relay selection scheme for cognitive two-way relay networks

A joint power control and relay selection scheme is considered for a cooperative and cognitive radio system where a secondary network shares spectrum with the primary network. In the secondary network, two secondary users （SUs） communicate with each other via an assist relay. The main point is to provide the best system performance to SUs while maintaining the interference power at primary user （PU） under a certain level. Using convex optimization, a closed-form solution is obtained when optimizing the power allocation among the two nodes and relay. Based on this result, a joint power control and relay selection scheme with fewer variable dimensions is proposed to maximize the achievable rate of the secondary system. Simulation results demonstrate that the sum rate of the cognitive two-way relay network increases compared with a random relay selection and fixed power allocation.

A Cause-Selecting Control Chart Method for Monitoring and Diagnosing Dependent Manufacturing Process Stages

Many industrial products are normally processed through multiple manufacturing process stages before it becomes a final product.Statistical process control techniques often utilize standard Shewhart control charts to monitor these process stages.If the process stages are independent,this is a meaningful procedure.However,they are not independent in many manufacturing scenarios.The standard Shewhart control charts can not provide the information to determine which process stage or group of process stages has caused the problems(i.e.,standard Shewhart control charts could not diagnose dependent manufacturing process stages).This study proposes a selective neural network ensemble-based cause-selecting system of control charts to monitor these process stages and distinguish incoming quality problems and problems in the current stage of a manufacturing process.Numerical results show that the proposed method is an improvement over the use of separate Shewhart control chart for each of dependent process stages,and even ordinary quality practitioners who lack of expertise in theoretical analysis can implement regression estimation and neural computing readily.

Study on Control of Pneumatic Selecting and Shifting Actuators Using Rapid Control Prototyping

A gearbox in-the-loop control platform using dSPACE real-time system is designed for the study on the control technology of pneumatic selecting and shifting actuators based on rapid control prototyping.The operational principle of such actuators was analyzed using dSPACE hardware and software,resulting in a better knowledge of the logical relationship among solenoid valves,gear positions of cylinders and system input/output.Based on these,a control model was developed under the Matlab/Simulink environment and rapidly improved to meet requirements through experiments.Relevant tests have shown that analysis efficiency on selecting and shifting actuators could be raised and development of control strategy facilitated.

Control strategy of central pattern generator gait movement under condition of attention selection

As a typical rhythmic movement, human being＇s rhythmic gait movement can be generated by a central pattern generator （CPG） located in a spinal cord by self- oscillation. Some kinds of gait movements are caused by gait frequency and amplitude variances. As an important property of human being＇s motion vision, the attention selection mechanism plays a vital part in the regulation of gait movement. In this paper, the CPG model is amended under the condition of attention selection on the theoretical basis of Matsuoka neural oscillators. Regulation of attention selection signal for the CPG model parameters and structure is studied, which consequentially causes the frequency and amplitude changes of gait movement output. Further, the control strategy of the CPG model gait movement under the condition of attention selection is discussed, showing that the attention selection model can regulate the output model of CPG gait movement in three different ways. The realization of regulation on the gait movement frequency and amplitude shows a variety of regulation on the CPG gait movement made by attention selection and enriches the controllability of CPG gait movement, which demonstrates potential influence in engineering applications.

爪哇虫草菌JS001浸种处理对水稻生长和防御褐飞虱的影响

【目的】明确新登记的真菌杀虫剂爪哇虫草菌Cordyceps javanica JS001在调控水稻生长和防御褐飞虱Nilaparvata lugens中的作用。【方法】室内分别用1×10^(4),1×106和1×10^(8)孢子/mL爪哇虫草菌JS001孢子悬浮液浸泡水稻种子48 h,以0.01%Triton X-100溶液浸种为对照,待培养8 d后,对水稻苗进行生长测定,并测定褐飞虱成虫对其的行为选择反应;通过气相色谱-串联质谱(GC-MS/MS)分析1×10^(8)孢子/mL爪哇虫草菌JS001孢子悬浮液浸种对水稻苗次生代谢化合物含量的影响。采用1×10^(7)孢子/mL爪哇虫草菌JS001孢子悬浮液和清水(对照)分别浸泡水稻种子48 h,于种子直播50 d后,调查稻田中稻飞虱和蜘蛛个体数量。【结果】室内测定结果表明,与对照相比,1×10^(6)和1×10^(8)孢子/mL爪哇虫草菌JS001孢子悬浮液浸种处理不仅显著促进水稻种子发芽、水稻苗根和茎叶的生长,而且降低褐飞虱成虫对水稻苗的选择性。化合物分析结果表明,与对照相比,1×10^(8)孢子/mL爪哇虫草菌JS001孢子悬浮液浸种处理的水稻苗中防御性化合物过氧化氢、油酸、辛烷等含量显著增加,能吸引褐飞虱的化合物2-壬酮含量显著降低。田间试验结果表明,与对照相比,1×10^(7)孢子/mL爪哇虫草菌JS001孢子悬浮液浸种显著降低稻田中稻飞虱数量,但对捕食性天敌蜘蛛个体数量无影响。【结论】爪哇虫草菌JS001浸种处理不但能促进水稻苗的生长,而且能提高水稻对褐飞虱的防御能力。田间试验进一步明确了爪哇虫草菌JS001在增强水稻防御稻飞虱危害中的作用。这些结果可为爪哇虫草菌的应用及稻飞虱生物防治策略的制定提供新途径。

解草啶包衣减轻丙草胺对栽培稻药害的技术

为了探寻高效防除杂草稻且对栽培稻安全的杂草治理技术,研究解草啶包衣对减轻丙草胺药害以及防治杂草稻的潜力。对栽培稻种子进行不同浓度(4%、7%、10%、13%、16%)解草啶包衣处理,以不含解草啶的种衣剂处理为对照(CK),分别研究不同浓度解草啶包衣处理对栽培稻种子萌发、幼苗生长发育和茎叶重、根重的影响,以及10%解草啶包衣处理对丙草胺防控杂草稻的药效的影响。结果表明,不同浓度解草啶包衣对栽培稻种子萌发均无显著差异;除最高浓度(16%)解草啶包衣处理之外,其他浓度处理对栽培稻幼苗的生长发育均无显著影响;解草啶添加浓度为10%时,栽培稻茎叶、根的鲜重抑制率均最低,说明其对栽培稻的保护效果最好。丙草胺防效结果表明,10%解草啶种子包衣处理对丙草胺防除杂草稻药效无显著影响。因此,推荐对栽培稻种子进行10%解草啶种子包衣处理,并在播后苗前施用丙草胺防除水稻田杂草稻。

无人机辅助蜂窝网络的模式选择与资源优化

研究了无人机(UAV,unmanned aerial vehicle)与蜂窝网络共存下的无线通信资源分配和优化方案。为了提高网络频谱利用率,无人机用户以全双工(FD,full duplex)或半双工(HD,half duplex)设备对设备(D2D,device-to-device)技术复用蜂窝频谱资源接入网络。此外,构造了一个联合接入控制、模式选择、功率控制和资源分配优化问题最大化网络的整体吞吐量,并保证无人机用户和地面蜂窝用户的服务质量要求。为解决这个问题,首先利用凸优化的第一阶段方法分别对全双工和半双工两种设备对设备模式进行接入控制和可行性判定。然后,对可接入无人机用户对使用凸凹过程(CCCP,convex and concave procedure)迭代算法求解功率控制问题。利用该局部最优值,原优化问题可以简化为加权最大化问题。最后,通过库恩-芒克斯(KM,Kuhn-Munrkes)算法对最优信道资源进行匹配,获得系统的全局最优吞吐量值。数值结果表明,所提方案能显著提高系统性能。

乳化沥青提高原油采收率研究进展

乳化沥青具有注入性能好、封堵强度高等优点,作为一种选择性堵剂在油田提高采收率领域比其他化学剂体系更具应用潜力。本文总结了国内乳化沥青堵水体系的开发历程及现场选择性堵水的应用效果。通过调研近年来国内外文献,概述了乳化沥青堵水的作用机理,一种是作为乳液的作用机理,主要是乳液颗粒被变形捕获产生贾敏效应和乳液液滴的机械滞留使水的流动阻力增大;另一种是其分散相也就是乳液破乳后沥青的作用机理,主要是沥青黏附在岩壁上起到的堵水作用。同时,总结了乳化沥青稳定的主要影响因素,包括温度、水相中的电解质浓度和pH值以及分散相中的沥青质,并且论述了各因素影响乳化沥青稳定性的作用机理。最后,详细叙述了乳化沥青应用于油田调剖堵水领域的最新研究进展,研究表明乳化沥青不仅具有优异的封堵效果,还具有独特的封堵选择性。此外,乳化沥青还能与CO_(2)吞吐、泡沫调驱组成复合增产技术进行现场应用,并且指出了乳化沥青应用于调剖堵水领域存在的问题与未来展望。

地方高校汉语言文学专业毕业论文存在问题与对策——以文山学院汉语言文学专业为个案

毕业论文是高校人才培养的重要环节,也是衡量高校办学质量的一项重要指标。调查发现,地方高校汉语言文学专业毕业论文整体质量不高,存在选题过于集中、学生写作能力偏弱、教师指导任务过重、质量监控不力等问题。在此基础上,提出提高思想认识、重构课程体系、加强选题指导、优化指导安排、调整开题时间、补齐监控短板等对策,以期有效提升毕业论文质量,进而提高人才培养质量。

40%砜吡草唑悬浮剂的除草活性及对花生的安全性评价

为明确砜吡草唑在花生田应用的可行性,采用整株生物测定法测定40%砜吡草唑悬浮剂对马唐Digitaria sanguinalis、狼尾草Pennisetum alopecuroides、稗Echinochloa crus-galli、藜Chenopodium album、反枝苋Amaranthus retroflexus及马齿苋Portulaca oleracea的除草活性,评价药剂对花生的安全性,并利用田间小区药效试验进行验证。结果表明:40%砜吡草唑悬浮剂对6种供试杂草均表现出极高活性,GR50为0.76~2.90 g/hm^(2),在13.32 g/hm^(2)剂量下,对供试杂草防效均达100%。40%砜吡草唑悬浮剂对3种禾本科杂草、3种阔叶杂草的毒力分别是960 g/L精异丙甲草胺乳油的5.60~9.30倍和22.16~25.24倍。在盆钵底部渗灌、喷淋浇水2种灌溉条件下,40%砜吡草唑悬浮剂对花生的GR10分别为212.03、87.68 g/hm^(2),剂量越高,对花生生长的抑制愈明显,对花生安全性欠佳。在盆钵底部渗灌条件下,砜吡草唑在花生和供试杂草间的选择性指数为29.45~142.30,具有较高选择性。田间试验表明,40%砜吡草唑悬浮剂施用剂量120~240 g/hm^(2)时,对杂草的总体防效在92.6%以上,花生增产率21.09%~22.71%,杂草防效及花生产量均显著高于960 g/L精异丙甲草胺乳油720 g/hm^(2)处理,所有药剂处理未见药害症状。综上,40%砜吡草唑悬浮剂可作为花生田低量、高效化学除草的备选药剂,但需关注砜吡草唑过量施用及降雨积水等因素导致的花生安全性问题。

危岩崩塌防治技术体系及工程选型分析

危岩崩塌防治技术是保障危岩工程安全稳定的关键。通过对危岩崩塌防治技术的优缺点、适用条件、工程设置原则以及选型程序的分析,认为危岩崩塌防治技术可分为主动防治技术、被动防治技术和辅助防治技术,各项防治技术设计时应充分考虑其适用条件,按照工程设置原则采纳使用,适时选择多种技术组合方式的治理措施进行危岩崩塌工程防治;危岩崩塌防治技术选型应遵循查清危岩体基本情况→评价危岩体状态→选择危岩防治技术→分析防治技术选型结果的基本程序,确定危岩崩塌防治技术选型程序各环节的关键参数,以确定合适的崩塌防治技术。研究成果可为危岩崩塌防治工程设计提供理论依据和关键技术支撑。

海洋命运共同体视域下中国参与全球海洋污染治理的现实基础和路径选择

当前全球海洋污染形势严峻,复杂的国际局势阻碍海洋污染治理合作,打破僵局,建构全球海洋污染治理体系具有紧迫性和必要性.基于全球海洋污染治理困境,运用地缘影响力模型分析中国参与全球海洋污染治理的现实基础,在海洋命运共同体视域下设计我国参与全球海洋污染治理的路径.主要结论如下:①全球海洋污染面临海洋污染治理滞后化,规则制定不合理化以及治理格局差异显著的困境;②我国参与全球海洋污染治理的现实基础包括日益夯实的经济发展基础,“一带一路”建设过程中提升的蓝色影响力以及在国际海洋污染治理合作,国内海洋污染治理中的经验积累;③我国参与全球海洋污染治理的主要路径是依托“一带一路”构建海洋污染治理平台,通过规则制定全局化,治理过程丰富化,体系革新阶段化焕新全球海洋污染治理体系.

基于GMM-Ada-LASSO模型的高维过程统计质量监控方法

针对高维数据往往不服从正态分布导致统计监控模型识别精度低、监控效率差的问题,文章提出一种基于高斯混合模型的变量选择控制图方法。首先,利用高斯混合模型将高维过程分解成若干个服从正态分布的子分布;然后,运用Adaptive LASSO算法识别潜在异常变量;最后,构建多元EWMA控制图实现高维过程统计质量监控。通过仿真实验,在六种不同情形下对所提方法的监控性能进行测试。结果表明,与传统MEW⁃MA和VS-MEWMA控制图相比,所提监控方法对非正态数据具有较强的稳健性,对高维过程具有良好的监控性能。

通过调节碳自由基的反应活性调控偶联反应产物和羰基化合物的选择性合成

在温和条件下,生物质(例如,生物质衍生醇、葡萄糖、木糖和木质素)通过光催化转化为高附加值化学品受到了广泛关注.目前,光催化氧化生物质衍生醇的主要产物是羰基化合物,即醛类化合物.相比之下,生物质衍生醇的C–C偶联产物(如氢化苯偶姻和乙二醇)是制药和合成化学领域重要的中间体和原料,具有较大的应用价值.然而,由于对反应机理的理解不足,生物质衍生醇的选择性光催化氧化生成对应的C–C偶联产物和羰基化合物仍然具有挑战性.本文合成了不同金属助催化剂(Au,Pt,Pd和Ru)负载的Cd0.6Zn0.4S复合光催化剂(M-CZS)用于光催化生物质衍生醇的选择性氧化.高分辨透射电镜和X射线光电子能谱结果证明了M-CZS复合光催化剂的成功合成.紫外-可见漫反射光谱结果表明,金属Au和Ru引入后,催化剂可见光的吸收能力增强.采用光致发光光谱、时间分辨光致发光光谱、光电流强度曲线和电化学阻抗曲线研究了催化剂的载流子分离和重组行为,结果表明,金属Au和Ru的引入促进了光生载流子的分离.所制Au-CZS催化剂生成C–C偶联产物(氢化苯偶姻)的速率为40 mmol gcat.^(‒1)h^(‒1),选择性大于98%.Ru-CZS催化剂生成羰基化合物(苯甲醛)的速率为21 mmol gcat.^(‒1)h^(‒1),选择性高达99%.催化剂稳定性测试结果表明,Au-CZS和Ru-CZS催化剂具有良好的光催化稳定性.此外,所制Au-CZS和Ru-CZS催化剂对各种生物质衍生醇具有良好的光催化活性和较高的选择性.电子顺磁共振谱与中间体捕获实验结果表明,反应过程中主要的反应中间体是苯甲醇C_(α)–H键断裂产生的碳自由基中间体.通过密度泛函理论计算研究了Au-CZS和Ru-CZS光催化生物质衍生醇选择性氧化合成偶联产物和羰基化合物过程中,每一步所需的热力学自由能,结果表明,碳自由基中间体在Au和Ru的弱和强吸附,分别导致了C–C偶联产物和羰基化合物的选择性合成.综上,本文报道了一种在Cd0.6Zn0.4S固溶体中引入不同金属助催化剂的策略,通过调节相应碳自由基中间体的反应活性,实现生物质衍生醇的选择性氧化,为生物质衍生醇的高选择性转化提供了新见解.

无线传感网络拥塞控制中节点选择强制博弈方法

无线传感网络中节点数据流量较大,分布范围较广,节点选择寻优计算复杂,导致浪费大量算力在节点选择上,拥塞控制效果不佳。提出一种无线传感网络拥塞控制中节点选择强制博弈方法,计算单条网络链路传输成本,依据传输数据耗费能量,计算传输节点可用能量比值,在传输变量权重值基础上,求得传输节点实际拥堵指数,完成节点选择。计算网络连接层的数据包丢弃概率,确定网络拥塞程度,汇聚节点数据流建立节点选择强制博弈模型,明确传感网络稳态传输条件,利用流量正态分布算法,在节点选择博弈中做出强制选择。经仿真分析证明:所提方法分组递交率保持在83%以上,丢包数量保持在100 pkt/s之内,网络传输节点端到端的延迟在0.3 s以内。