Effect of ZnO on the performance of Ag/SiO_2 catalyst for the vapor-phase synthesis of 3-methylindole

The vapor-phase synthesis of 3-methylindole over Ag/SiO2 doped with ZnO was investigated. The catalysts were characterized by XRD, H2- TPR, NH3-TPD and TG techniques. The results indicated that ZnO promoter greatly enhanced the initial activity of the catalyst but disfavored its stability. H2-TPR and XRD results showed that the reduction peak of Ag2O shifted to higher temperature and the intensity of silver diffraction peaks was much weaker after the addition of ZnO promoter to Ag/SiO2. This indicated that there existed the interaction between Ag2O and SiO2-ZnO which promoted the silver particles dispersing on the support and inhibited the sintering of silver during the reaction. NH3-TPD and TG results revealed that the acid amounts of the catalyst and coking increased after adding ZnO to Ag/SiO2, which resulted in the deactivation of Ag/SiO2-ZnO catalyst rapidly.

The Perception of Health Workers and Stakeholders Involved in the Process of Selecting Indigent in Burkina Faso

Background: Indigent selected for their health care is complex and poses enormous challenges. The actors involved have an influence on health actions and their perception is decisive for better care for the indigent. Little evidence exists on these perceptions and this paper has captured this. Methods: A case study involved 163 participants with a questionnaire and an interview guide. The quantitative responses were classified according to a measurement scale, proportions and overall indices of perception (Ip) and satisfaction (CSAT) were calculated. The relationship between variables was investigated using chi-square. Thematic analysis was used with qualitative data. The study met ethical requirements. Results: The participants had a positive perception of the selection: Ip = 0.77, but a minority (1/5) were dissatisfied with the selection. The perception of selection did not differ significantly depending on the experience of the actors. For the vast majority, the definition of indigent was satisfactory (CSAT = 91.4). The selection was done in a top down fashion and steps such as setting up committees, informing stakeholders, had shortcomings which negatively impacted the effectiveness of the selection. The needs of the participants included transparency in the indigent select process, matching the tools for selecting the indigent to the context, strengthening of local action, deconstruction of prejudices in terms of the indigent, power of actors to act, and importance for health services to reach out to the indigent. Conclusion: Considering the perception of the actors as well as their needs will improve the selection for effective care of the indigent.

A New Population Initialization of Particle Swarm Optimization Method Based on PCA for Feature Selection

In many fields such as signal processing,machine learning,pattern recognition and data mining,it is common practice to process datasets containing huge numbers of features.In such cases,Feature Selection(FS)is often involved.Meanwhile,owing to their excellent global search ability,evolutionary computation techniques have been widely employed to the FS.So,as a powerful global search method and calculation fast than other EC algorithms,PSO can solve features selection problems well.However,when facing a large number of feature selection,the efficiency of PSO drops significantly.Therefore,plenty of works have been done to improve this situation.Besides,many studies have shown that an appropriate population initialization can effectively help to improve this problem.So,basing on PSO,this paper introduces a new feature selection method with filter-based population.The proposed algorithm uses Principal Component Analysis(PCA)to measure the importance of features first,then based on the sorted feature information,a population initialization method using the threshold selection and the mixed initialization is proposed.The experiments were performed on several datasets and compared to several other related algorithms.Experimental results show that the accuracy of PSO to solve feature selection problems is significantly improved after using proposed method.

Living on the edge： Effects of body size, group density and microhabitat selection on escape behaviour of southern leopard frogs Lithobates sphenocephalus

Models of optimal escape strategy predict that animals should move away when the costs of fleeing （metabolic and opportunity costs） are outweighed by the costs of remaining. These theoretical models predict that more vulnerable individuals should be more reactive, moving away when an approaching threat is further away. We tested whether escape behaviour （includ- ing ＇escape calling＇） ofLithobates sphenocephalus approached by a human was influenced by body size or the initial microhabi- tat that the individual was found in. Irrespective of their size, frogs in the open tended to remain immobile, enhancing their cryp- sis. Frogs in cover showed different responses according to their body size, but, contrary to our initial predictions, larger frogs showed greater responsiveness （longer flight initiation distance and distances fled） than small frogs. Small frogs tended to remain closer to water and escaped into water, while larger individuals were more likely to jump to terrestrial cover and call during escape. Density of frogs near the focal animal had no effect on escape behaviour. This study indicates a range of escape responses in this species and points to the importance of divergent escape choices for organisms which live on the edge of different environments .

Feature Selection for the Prediction of Translation Initiation Sites

Translation initiation sites (TISs) are important signals in cDNA sequences. In many previous attempts to predict TISs in cDNA sequences, three major factors affect the prediction performance: the nature of the cDNA sequence sets, the rel- evant features selected, and the classification methods used. In this paper, we examine different approaches to select and integrate relevant features for TIS pre- diction. The top selected significant features include the features from the position weight matrix and the propensity matrix, the number of nucleotide C in the se- quence downstream ATG, the number of downstream stop codons, the number of upstream ATGs, and the number of some amino acids, such as amino acids A and D. With the numerical data generated from these features, different classifi- cation methods, including decision tree, naive Bayes, and support vector machine, were applied to three independent sequence sets. The identified significant features were found to be biologically meaningful, while the experiments showed promising results.

Selection for Cheaper Amino Acids Drives Nucleotide Usage at the Start of Translation in Eukaryotic Genes

Coding regions have complex interactions among multiple selective forces,which are manifested as biases in nucleotide composition.Previous studies have revealed a decreasing GC gradient from the 5′-end to 3′-end of coding regions in various organisms.We confirmed that this gradient is universal in eukaryotic genes,but the decrease only starts from the~25th codon.This trend is mostly found in nonsynonymous(ns)sites at which the GC gradient is universal across the eukaryotic genome.Increased GC contents at ns sites result in cheaper amino acids,indicating a universal selection for energy efficiency toward the N-termini of encoded proteins.Within a genome,the decreasing GC gradient is intensified from lowly to highly expressed genes(more and more protein products),further supporting this hypothesis.This reveals a conserved selective constraint for cheaper amino acids at the translation start that drives the increased GC contents at ns sites.Elevated GC contents can facilitate transcription but result in a more stable local secondary structure around the start codon and subsequently impede translation initiation.Conversely,the GC gradients at four-fold and two-fold synonymous sites vary across species.They could decrease or increase,suggesting different constraints acting at the GC contents of different codon sites in different species.This study reveals that the overall GC contents at the translation start are consequences of complex interactions among several major biological processes that shape the nucleotide sequences,especially efficient energy usage.

An Upper Limit for Iterative Learning Control Initial Input Construction Using Singular Values

Selecting a proper initial input for Iterative Learning Control (ILC) algorithms has been shown to offer faster learning speed compared to the same theories if a system starts from blind. Iterative Learning Control is a control technique that uses previous successive projections to update the following execution/trial input such that a reference is followed to a high precision. In ILC, convergence of the error is generally highly dependent on the initial choice of input applied to the plant, thus a good choice of initial start would make learning faster and as a consequence the error tends to zero faster as well. Here in this paper, an upper limit to the initial choice construction for the input signal for trial 1 is set such that the system would not tend to respond aggressively due to the uncertainty that lies in high frequencies. The provided limit is found in term of singular values and simulation results obtained illustrate the theory behind.

Exploring the Link Between Topic Initiation and Chinese Learner Involvement in NS-NNS Casual Conversations

This paper reports on a case study which explored Chinese L2 learners＇ conversational involvement in NS-NNS interaction in a study-abroad context. In particular, the study investigated the possible link between topic initiation and conversational involvement examined under the commonly identified topic genres in casual conversations, including ＂observation＂, ＂opinion seeking/providing＂, ＂story-telling＂, ＂chat＂ topics and ＂gossip＂. The findings show differences in the choices of topic initiation between the NS English group and the NNS Chinese group. Further analysis found that the participants＇ topic initiations did not necessarily lead to their active conversational involvement and suggests that the mere fact of getting involved in a topic does not always produce a sense of shared common ground between/among the conversationalists. The positive link between topic initiation and conversational involvement （such as in ＂observation＂）, and its impact upon L2 learners are also discussed in this study, confirming the social constructionist view that social roles and interpersonal relations are created and recreated at a micro-level in everyday discourse.

北京企业对“一带一路”沿线国家和地区OFDI研究

为了进一步推动北京企业对"一带一路"沿线国家和地区直接投资,从北京市出发,以北京企业为主体,基于投资规模、区域分布和产业选择的现状,就北京企业对沿线国家和地区OFDI的情况进行分析,据此,从国家层面和企业层面,提出优化北京企业对"一带一路"沿线国家和地区直接投资的相关建议。

多策略融合的蛇优化算法及其应用

针对蛇算法寻优阶段交互性差,初始种群随机程度严重,易陷入局部最优解等问题,提出了一种多策略融合的蛇优化算法(multi-strategy snake optimizer, MSSO)。首先,利用正交矩阵对蛇种群进行初始化,使个体分布更加均匀;其次,设计探索开发阶段切换的自适应方程,用以替换原有的食物量与温度阈值,使算法进行自适应阶段切换;最后,使用联合反向选择策略替换算法原有的新个体孵化方法,提高算法收敛精度的同时加快算法收敛效率。选取10个基准测试函数从不同角度对MSSO算法进行实验,测试算法性能,分析各策略的有效性,并使用Wilcoxon秩和检验来证明算法显著性,通过两个工程应用仿真实验来验证MSSO的实用性。各实验结果表明MSSO较比较算法综合表现更优,证明MSSO算法改进在寻优能力、鲁棒性、实用性等方面均有所提升。

基于改进麻雀搜索算法的水质模型多参数反演

水质模型参数取值对模型的模拟精度影响很大,为提高BOD-DO水质模型参数反演精度,首先在DobbinsCamp BOD-DO水质模型的基础上,以BOD和DO浓度计算值与实测值之差的加权平方和最小为目标函数,构建了Dobbins-Camp BOD-DO水质多参数反演模型;然后针对麻雀搜索算法(Sparrow Search Algorithm,SSA)求解精度低、稳定性不足和易陷入局部最优等问题,引入Sine混沌映射和对立学习、转移概率以及差分变异3个策略,分别从提高初始种群多样性、扩大搜索空间以及增强种群跳出局部最优的能力三方面对SSA算法进行改进,提出了一种多策略改进的麻雀搜索算法(Multi-strategy Improved Sparrow Search Algorithm,MISSA),并将其应用于Dobbins-Camp BOD-DO水质多参数反演模型的求解;最后通过数值实验将得到的反演结果与SSA算法、模拟退火算法、粒子群算法、遗传算法四种优化算法进行对比,并探讨了参数初值选取和观测噪声水平对反演结果的影响。结果表明:MISSA算法的计算性能明显优于对照组中的4种算法,且能显著降低初值选取对BOD-DO水质模型参数反演结果的影响,当观测数据的噪声水平不超过5%时,MISSA算法可有效提高反演结果的稳定性。该结果验证了MISSA算法在反演Dobbins-Camp BOD-DO水质模型参数的有效性,为水质模型参数求解提供有益参考。

2型糖尿病患者初始使用胰岛素的决策参与影响因素质性研究的Meta整合

目的从患者和医护人员的角度归纳分析2型糖尿病患者初始使用胰岛素的决策参与影响因素的质性研究,为促进患者的决策参与提供参考。方法系统检索CINAHL,Cochrane Library,EMBASE,PubMed,Web of Science,PsycINFO,中国知网,万方,维普和SinoMed收录的关于2型糖尿病患者初始胰岛素决策参与影响因素的质性研究,检索日期从建库至2023年9月30日,采用澳大利亚乔安娜布里格斯研究所(Joanna Briggs Institute,JBI)循证卫生保健中心质性研究质量评价工具对纳入文献进行评价,并采用汇集性整合方法对结果进行整合。结果共纳入文献19篇,提炼出20个研究结果,归纳成7个类别(患者决策相关价值观、患者决策参与的角色偏好、患者自身疾病情况、医护人员在患者决策参与中的角色定位、医护人员的专业素质、患者与医护人员的关系、医疗机构支持程度),共4个整合主题(患者个人因素、医护人员因素、患者-医护人员互动因素、医疗机构因素)。结论2型糖尿病患者胰岛素初始使用的决策参与受到患者自身、医护人员和医疗机构的影响,需要多方人员努力,不仅引导患者积极参与决策,医护人员和医疗机构也要提供有效的决策支持。

数字“一带一路”经济合作的理论内涵、实践成效与路径选择

共建“一带一路”倡议下,数字技术的融合应用推动了共建国家之间经济合作的开展。数字“一带一路”经济合作具有以数字技术、数字合作、数字治理为基本要素,以数字基础设施、数字金融服务等为支撑,以外部动力和外在保障为实践选择的理论内涵。当前,数字“一带一路”经济合作在数字基础设施建设、数字国际市场黏性、数字安全治理、数字赋能产业、数字商业生态协同这五方面具有显著成效。然而,在数字核心技术研发、数字地域融合、数字服务体系构建、数字安全治理等方面,数字经济合作仍面临挑战,阻碍了共建国家数字经济发展和“一带一路”倡议实施的深度融合。为此,聚焦数字经济的基础性、创新性、包容性、赋能产业发展以及激发数据挖掘这五方面,提出发展数字“一带一路”经济的路径选择。

涉案企业合规考察启动条件研究

准确把握涉案企业合规考察的启动条件是保证合规改革正当性、督促司法机关依法办案、确保法律正确适用、维护国家刑事法治化的重要保障。然而,目前并无涉案企业合规考察启动的统一标准,实践中启动合规考察存在以公共利益为主要导向、将企业合规与清理“挂案”相结合、个人犯罪中要求企业合规等误区。通过对域外涉案企业合规考察适用范围和启动条件的比较分析,结合我国实践,可从否定条件、准入条件及考量因素三个方面综合分析是否启动合规考察,实现我国涉案企业合规考察启动的规范化和法治化。

《学位法》时代学术复核制度的法治逻辑

学术复核制度作为维护学位申请人合法权益、规范学位授予权行使、实质性化解学位争议的一大制度创新,旨在发挥其促进学术公正、尊重学术自治的价值功能。为了考察实践中高校学术复核制度的运行逻辑,本研究对96所“双一流”建设高校的准学术复核制度文本进行分析发现,当前学术复核制度在实践中面临受理范围类别有限且条件苛刻、受理机构独立性欠缺和专业性不足、专家回避原则执行不力和人员构成不尽合理、复核处理期限不明和申请人参与程度低等多重法治困境。为将学术复核制度建设纳入法治轨道,我国应从规范制定、制度实施、强化监督三个维度着手,建立健全《学位法》框架下的学术复核办法,完善学术复核内部治理体系,建立和完善学术复核制度的国家监督体系,以促进学位争议案件中学术评价纠纷的实质和公正解决。

Controlled Synthesis of Polymers

Controlled synthesis is central to obtaining polymers with accurate structures and excellent performances.Recent research in the controlled synthesis of polymers has focused on optimizing monomers,initiation systems,and reaction conditions.The satisfactory sequence,topological structure,and dispersity have been achieved to satisfy the growing demand for functional polymers.This re-view summarizes the selection of monomers of various types and structures,the innovation of initiation systems,and the optimiza-tion of reaction conditions in the controlled synthesis of polymers and discusses their challenges and opportunities.

基于改进MOEA/D的模糊柔性作业车间调度算法

针对实际生产车间中加工时间的不确定性,将加工时间以模糊数的形式表示,建立以最小化模糊最大完工时间和模糊总材料消耗为优化目标的多目标模糊柔性作业车间调度问题数学模型,提出一种改进基于分解的多目标进化算法(IMOEA/D)进行求解。该算法基于机器和工序两层编码并采用混合的初始化策略提高初始种群的质量,利用插入式贪婪解码策略对机器的选择进行解码,缩短总加工时间;采用基于邻域和外部存档的选择操作结合改进的交叉变异算子进行种群更新,提高搜索效率;设置邻域搜索的启动条件,并基于4种邻域动作进行变邻域搜索,提高局部搜索能力;通过田口实验设计方法研究关键参数对算法性能的影响,同时得到算法的最优性能参数。在Xu 1~Xu 2、Lei 1~Lei 4和Remanu 1~Remanu 4测试集上将所提算法与其他算法进行对比,结果表明,IMOEA/D算法的解集数量和目标函数值均较优,在Lei 2算例获得的解集个数为对比算法的2倍以上。

三电平逆变器SHEPWM非线性方程组的求解

初值对三电平逆变器特定谐波消除脉宽调制(selected harmonic elimination PWM,SHEPWM)非线性方程组求解过程收敛与否和收敛速度都至关重要。为了提高非线性方程组的求解速度,提出了一种以冲量相等、重心重合为原则的求取非线性方程组初值的方法,使得每一个M下取得的初值往往可以保证大多数M(以0.01为分辨率)值对应的非线性方程组收敛,而且显著加快了迭代的收敛速度。对采用所提方法求得的初值不能收敛的M值对应的方程组求解,采取了以其相邻的M值对应的数值解为初值的有效方法,结合这两种初值方法。以11个开关切换点为例,以0.01为调制度M的分辨率,对M从1.15到0.01范围内的每一点上的非线性方程组,采用Matlab6.5中提供的基于牛顿迭代法的fsolve函数,分别求解,并给出至少一个可以实现的数值解。讨论了三电平逆变器SHEPWM问题的多解现象和简单的优化原则。建立了二极管箝位三电平逆变器实验电路模型,对所求SHEPWM的解抽样进行实验,实验证明了所求解能够实现基波控制目标并消除选定的低频次谐波,证明该文提出的方法是有效的。

中国抗震规范强震记录选取的初选条件研究

合理的强震记录选取对于结构时程分析具有重要意义,而其地震动特性是否符合要求是判断选取结果是否合理的先决条件。我国建筑抗震设计规范中设计地震分组与设防烈度的概念并无清晰对应的地震动参数指标,故工程及研究人员在实际选波过程中往往模糊了上述要求。利用地震烈度和峰值加速度的衰减关系,首先给出了各设防烈度下震级的初选范围,进而针对远场的高烈度设防地区给出了距离初选范围,最后结合目前常用的国内外强震记录数据现状给出了场地类别筛选的建议。结论可为工程建筑依据抗震规范进行强震记录选取提供参考。

C2C环境下感知在线评论与初始信任的调节因素

对网上卖家缺乏初始信任已经成为顾客选择网上购物的一个主要障碍.通过对C2C网上购物环境下的顾客进行问卷调查,探讨感知在线客户评论与顾客初始信任之间的影响因素,挖掘顾客专业能力和产品参与的调节效应.研究发现顾客专业能力对评论质量与顾客初始信任,以及评论者专业能力与顾客初始信任之间的关系具有调节作用;产品参与对评论质量、评论数量和评论者专业能力与初始信任之间的关系具有调节作用.