A SARS-CoV-2 neutralizing antibody discovery by single cell sequencing and molecular modeling

Although vaccines have been developed,mutations of SARS-CoV-2,especially the dominant B.1.617.2(delta)and B.1.529(omicron)strains with more than 30 mutations on their spike protein,have caused a significant decline in prophylaxis,calling for the need for drug improvement.Antibodies are drugs preferentially used in infectious diseases and are easy to get from immunized organisms.The current study combined molecular modeling and single memory B cell sequencing to assess candidate sequences before experiments,providing a strategy for the fabrication of SARS-CoV-2 neutralizing antibodies.A total of 128 sequences were obtained after sequencing 196 memory B cells,and 42 sequences were left after merging extremely similar ones and discarding incomplete ones,followed by homology modeling of the antibody variable region.Thirteen candidate sequences were expressed,of which three were tested positive for receptor binding domain recognition but only one was confirmed as having broad neutralization against several SARS-CoV-2 variants.The current study successfully obtained a SARS-CoV-2 antibody with broad neutralizing abilities and provided a strategy for antibody development in emerging infectious diseases using single memory B cell BCR sequencing and computer assistance in antibody fabrication.

Emission-side drivers affecting carbon neutrality based on vegetation carbon sequestration:Evidence from China

To address climate change,the world needs deep decarbonization to achieve carbon neutrality(CN),which implies net-zero human-caused CO_(2) emissions in the atmosphere.This study used emission-side drivers,including socioeconomic and net primary productivity(NPP)-based factors,to determine the changes in CN based on vegetation carbon sequestration in the case of China during 2001-2015.Spatial exploratory analysis as well as the combined use of production-theoretical decomposition analysis(PDA)and an econometric model were also utilized.We showed that CN was significantly spatially correlated over the study period;Yunnan,Heilongjiang,and Jilin presented positive spatial autocorrelations,whereas Guizhou showed a negative spatial autocorrelation.More than half of CN declined over the period during which potential energy intensity(PEIE)and energy usage technological change were the largest negative and positive drivers for increasing CN.PEIE played a significantly negative role in increasing CN.We advise policymakers to focus more on emission-side drivers(e.g.,energy intensity)in addition to strengthening NPP management to achieve CN.

Nonlinear Model Algorithmic Control of a pH Neutralization Process

Control of pH neutralization processes is challenging in the chemical process industry because of their inherent strong nonlinearity. In this paper, the model algorithmic control (MAC) strategy is extended to nonlinear processes using Hammerstein model that consists of a static nonlinear polynomial function followed in series by a linear impulse response dynamic element. A new nonlinear Hammerstein MAC algorithm (named NLH-MAC) is presented in detail. The simulation control results of a pH neutralization process show that NLH-MAC gives better control performance than linear MAC and the commonly used industrial nonlinear propotional plus integral plus derivative (PID) controller. Further simulation experiment demonstrates that NLH-MAC not only gives good control response, but also possesses good stability and robustness even with large modeling errors.

Continuous-Time Models for Firm Valuation and Their Collateral Effect on Risk-Neutral Probabilities and No-Arbitraging Principle

Extensions of Merton’s model(EMM)considering the firm’s payments and generating new types of firm value distribution are suggested.In the open log-value/time space,these distributions evolve from initially normal to negatively skewed ones,and their means are concave-down functions of time.When payments are set to zero or proportional to the firm value,EMM turns into the Geometric Brownian model(GBM).We show that risk-neutral probabilities(RNPs)and the no-arbitraging principle(NAP)follow from GBM.When firm’s payments are considered,RNPs and NAP hold for the entire market for short times only,but for long-term investments,RNPs and NAP just temporarily hold for individual stocks as far as mean year returns of the firms issuing those stocks remain constant,and fail when the mean year returns decline.The developed method is applied to firm valuation to derive continuous-time equations for the firm present value and project NPV.

Guaranteed Cost Control for Uncertain Nonlinear Time-Delay Neutral Systems Based on T-S Fuzzy Model

The problem of guaranteed cost fuzzy controller is studied for a class of nonlinear time-delay neutral sys-tems with norm-bounded uncertainty based on T-S model. The sufficient conditions are first derived for the existenceof guaranteed cost fuzzy controllers. These sufficient conditions are equivalent to a kind of linear matrix inequalities.Furthermore, a convex optimization problem with LMI constraints is formulated to design the optimal guaranteedcost controller.

Shale gas production evaluation framework based on data-driven models

Increasing the production and utilization of shale gas is of great significance for building a clean and low-carbon energy system.Sharp decline of gas production has been widely observed in shale gas reservoirs.How to forecast shale gas production is still challenging due to complex fracture networks,dynamic fracture properties,frac hits,complicated multiphase flow,and multi-scale flow as well as data quality and uncertainty.This work develops an integrated framework for evaluating shale gas well production based on data-driven models.Firstly,a comprehensive dominated-factor system has been established,including geological,drilling,fracturing,and production factors.Data processing and visualization are required to ensure data quality and determine final data set.A shale gas production evaluation model is developed to evaluate shale gas production levels.Finally,the random forest algorithm is used to forecast shale gas production.The prediction accuracy of shale gas production level is higher than 95%based on the shale gas reservoirs in China.Forty-one wells are randomly selected to predict cumulative gas production using the optimal regression model.The proposed shale gas production evaluation frame-work overcomes too many assumptions of analytical or semi-analytical models and avoids huge computation cost and poor generalization for numerical modelling.

Neutral Higgs Boson Pair Production in Standard Model with the Fourth GenerationQuarks at LHC

We investigated the neutral Higgs boson pair production at the CERN Large Hadron Collider (LHC) in the SM with four families. We found that the gluon-gluon fusion mode is the most dominant one in producing neutral Higgs boson pair at the LHC, and it can be used to probe the trilinear Higgs coupling. If the heavy quarks of the fourth generation really exist within the SM, they can manifest their effect on the cross section of the Higgs pair production process at the LHC. Our numerical results show that there will be neutral Higgs boson pair production events per year if the next generation heavy quarks really exist, while there will be only events produced per year if there are only three families in the SM.

Electrical Neutrality and Symmetry Restoring Phase Transitions at High Density in a Two-Flavor Nambu-Jona-Lasinio Model

A general research on chiral symmetry restoring phase transitions at zero temperature and finite chemical potentials under electrical neutrality condition has been conducted in a Nambu-Jona-Lasinio model to describe twoflavor normal quark matter. Depending on whether mo/A, the ratio of dynamical quark mass in vacuum and the 3D momentum cutoff in the loop integrals, is less or greater than 0.413, the phase transition will be of the second or first order. A complete phase diagram of u quark chemical potential versus mo is given. With the electrical neutrality constraint, the region where the second order phase transition happens will be wider than the one without electrical neutrality limitation. The results also show that, for the value ofmo/A from QCD phenomenology, the phase transition must be of the first order.

Consumer behavior patterns of carbon neutral label using the unified theory of acceptance and use of technology

China has paid considerable attention to developing and implementing a carbon labeling system in response to increasing environmental issues such as global warming.This paper aims to provide a theoretical basis for formulating and implementing a carbon labeling system in China through a study of consumer acceptance behavior and its influencing factors.This paper constructed an extended model of consumers’acceptance behavior of carbon neutral labels based on the theories and methods of Unified Theory of Acceptance and Use of Technology(UTAUT)and analyzed the effects of five factors(carbon label cognition,performance expectancy,effort expectancy,social influence,and facilitating factors)on consumer carbon neutral label acceptance and adoption.The structural equation model analysis revealed that carbon label cognition,performance expectancy,social influence,and facilitating factors significantly,and positively impact consumers’acceptance of carbon neutral labels.Moreover,carbon label cognition,performance expectancy,and facilitating factors significantly,and positively affect consumers’carbon neutral label adoption behavior.Meanwhile,carbon label cognition,and effort expectancy have no significant impact on consumers’willingness to accept carbon neutral labels,which in turn significantly impacts consumers’carbon neutral label adoption behavior.According to the research findings,increasing the promotion of carbon labeling and improving the practical strategies and management recommendations for carbon label design are proposed.

气候变化与碳中和

工业化以来化石燃料的广泛使用使大气中的二氧化碳浓度急剧升高,造成全球气候变暖、极端天气气候事件频发。为有效应对和减缓气候变化,国际社会通过《巴黎协定》设定了2℃和1.5℃温控目标,由此提出了碳中和的概念。文章介绍了全球变暖的基本事实、人类碳排放对工业化以来全球变暖的作用,归纳了关于未来气候变化的主要结果,阐释了1.5/2℃温升阈值与碳中和的关系,概述了国际社会为有效应对全球变暖而在减少碳排放方面的努力。

三电平辅助变流器寿命优化控制

辅助变流系统是动车组车辆上关键的电气组成部分,主要为空调机组、风机、照明等交流负载提供稳定的三相电源。结温是影响动车组三电平辅助变流器IGBT(Insulated-gate Bipolar Transistor)模块寿命的主要因素。为了提高动车组三电平中点钳位(Neutral-Point Clamped,NPC)型辅助变流器寿命,提出一种降低结温的模型预测电流控制(Model Predictive Current Control,MPCC)策略。首先,考虑传统MPCC在每个采样周期需要代入27个电压矢量循环计算,计算量较大,因此将三电平基本电压矢量划分在间隔60°的6个扇区中,通过计算电压矢量在两相静止坐标下的相角,进而判断参考电压矢量所处扇区,将备选矢量数目从27缩减至10,减少了计算量;其次,传统MPCC直接应用于动车组辅助变流器会使IGBT模块的结温较高,老化速度加快,对变流器安全稳定运行产生不可预测的损害,本文对IGBT模块的开关损耗和导通损耗进行近似等效,得到了和集射极电压、集电极电流相关的功率损耗因子。通过预测每相电流的方向,进而预测IGBT模块的开关和导通情况,动态加入功率损耗因子,并在代价函数中约束每相IGBT及其续流二极管(Free Wheeling Diode,FWD)的功率损耗,使得最优电压矢量在降低功率损耗的同时保证一定的控制性能。通过仿真与实验验证,本文所提方法相比传统MPCC策略降低了功率器件的结温,提高了变流器寿命。

“双碳”目标下黄河流域绿色技术创新效率评价及影响因素

基于“双碳”目标视角,采用超效率动态网络SBM模型测算黄河流域82市(盟)2011—2021年绿色技术创新的综合效率、科技研发效率及成果转化效率,并利用面板Tobit回归模型检验外部环境因素对三种效率的影响。结果表明:将CO_(2)排放量纳入指标体系后,中下游地区绿色技术创新综合效率得以提升,上游地区效率反而下降;黄河流域绿色技术创新综合效率呈波动上升趋势,科技研发效率起引擎作用;黄河流域绿色技术创新综合效率区域差异明显,成果转化效率差异是综合效率差异的主要来源;经济发展水平、产业结构高级化、人力资本禀赋、对外开放水平、政府支持力度和环境规制强度对三种效率的影响具有区域异质性。建议黄河流域提高绿色技术创新能力,完善创新成果转化平台,推动能源和产业结构升级。

中国经济增长与煤炭消费脱钩及影响因素分析

结合中国各省(区、市)2005~2019年的煤炭消费数据及社会经济发展数据,借助Tapio脱钩模型分析了各省(区、市)煤炭消费与经济增长之间的脱钩情况及时空演变.结果表明:各省(区、市)煤炭消费脱钩状态总体呈现出从增长负脱钩、增长联结向弱脱钩、强脱钩转变的较好趋势,大部分地区处于弱脱钩状态.从空间分布来看,东部地区煤炭消费与经济增长脱钩情况明显优于中部地区与西部地区,强脱钩省(区、市)呈现出由北京市、上海市和四川省这3个省(区、市)向外扩张的趋势,而宁夏与新疆的脱钩状态尚不理想,在增长联结与增长负脱钩之间波动.在此基础上,通过拓展的STIRPAT模型和空间杜宾模型分析了影响各省(区、市)脱钩情况的主要因素,并发现能源结构、能源强度、R&D强度、人口密度、对外开放水平、新造林面积、产业结构因素对煤炭消费脱钩指数具有显著影响.未来应加强减煤工作的顶层设计、技术投入与研发和调整能源结构来促进煤炭消费脱钩.

基于电压补偿的双端直流配电网电压就地协调控制

双端直流配电网是一种双端电源供电的网络结构,可为直流负荷提供更加稳定和可靠的电源电压。然而,负荷的功率波动和不平衡使线路电压跌落增大,可能导致直流负荷的电压不平衡度和电压偏差指标越限,影响直流负荷的正常运行。文中基于电压源型换流器(VSC)外环电压控制,考虑中线电压补偿,提出基于电压补偿等效模型的直流配电网电压偏差及不平衡度联合抑制策略,实现直流配电网电压就地协调控制。首先,建立双端直流配电网潮流模型,将VSC电压下垂控制引入潮流模型,分析不同控制策略下的电压偏差和不平衡度的特性。其次,在此基础上,以电压最低点为分点获得双端电源供电回路压降的简化等效模型,并利用最小二乘法实现等效阻抗参数辨识,构建双端直流配电网的电压补偿等效模型。以参数辨识结果作为电压外环控制输入,提出考虑中线电压补偿的双端直流配电网电压就地协调控制策略。最后,在MATLAB/Simulink中搭建仿真模型,验证了双端直流配电网潮流模型的正确性和控制策略的有效性。

基于数学模型的造纸机水针移动控制系统优化研究

为有效应对造纸机水针移动惯性所造成的定位偏差,确保水针精准且快速移动,以拟合优化方法构建了造纸机水针移动控制数学模型。采取变速双控制中性区方法,以反复测试寻找控制中性区数值的合理范围,并针对性建立水针移动与中性区数值的数学模型,以求解控制中性区数值。实际应用验证结果表明,变速双控制中性区方法的引进使造纸机水针移动曲线变化趋向于平缓,且终止位置与设定位置误差控制于0.79%,精确度非常高;相比传统变速单控制中性区方法,水针移动响应时间缩短了25s。

基于T型三电平整流器的改进模型预测功率控制

为解决传统模型预测功率控制(MPPC)的谐波含量高、计算量大、权重因子设计困难等问题,提出了一种改进MPPC。首先使用一种低运算量的最优扇区判断方法,再通过代价函数最小化原则来确定其作用时间。为平衡中点电位(NP-V),将矢量序列分为P型序列和N型序列,它们对NP-V的影响相反,使用一个代价函数选择下一时刻选用的矢量序列类型,从而达到动态平衡NP-V的目的,同时消除了权重因子带来的影响。为提高输出电压的动态响应速度,使用改进滑模控制(SMC)来代替传统MPPC中的PI控制对直流侧电压进行控制。最后,仿真与实验验证了所提控制策略在电网侧电流、直流输出电压、输出功率及算法运算时间方面具有有效性。

我国城镇职工养老保险精算因子测算与比较——基于退休制度改革的探讨

为缓解老龄化趋势下养老金支出不断增加的压力,以我国城镇职工养老保险体系的可持续发展为着眼点,探讨延迟退休的养老金待遇给付标准设计。建立养老金财富精算模型,从精算中性的视角测算我国9个省份精算因子Φ值和α值,并测算利率变化对精算中性调整系数α值的影响。实证结果表明,在北京、海南、河南和黑龙江,按照目前的养老金给付制度,延迟退休会增加参保人的养老金财富。若改革退休制度、延迟退休年龄,对不同退休年龄参保人养老金待遇的给付标准可以参考α值设定。

H形钢构件双向压弯下全过程弯矩计算模型

为探究可发展全截面塑性的H形钢构件在双向压弯加载全过程中塑性应力及两主轴弯矩的发展机制,基于经由已有实验数据校核过的建模方法,采用ABAQUS建立了不同轴压比、腹板和翼缘宽厚比的H形截面构件在不同加载角度下的参数分析模型。结合有限元分析结果,考察了双向压弯下H形截面钢构件的塑性应力发展规律,引入平截面假定,对其应力分布形式进行一定的简化处理。进一步,通过最小二乘法拟合得到相关参数,建立加载位移、塑性发展程度和宏观承载能力三者之间内在联系,构建H形钢构件双向弯矩的理论计算模型。该模型充分考虑了截面尺寸、位移加载方向角、轴压比和加载位移的影响。通过对模型计算结果的分析,验证了该模型可得到构件在加载任意时刻的应力分布形式,并为考虑一定截面塑性发展的双向抗弯设计提供更为简便的设计方法。

考虑双碳目标的新型火力发电企业环境效率测度

我国提出了“双碳目标”以改善生态环境、实现可持续发展。火力发电行业无疑是促进节能减排的重要领域,有必要对其环境效率进行测度。从传统火力发电企业定义出发提出新型火力发电企业概念,构建考虑碳排放的环境效率评价体系,采用USSBM模型和GML指数从静态和动态两角度对15家新型火力发电企业2017—2021年度环境效率进行评估。结果表明,新型火力发电行业环境效率处于较高水平但仍有一定的进步空间,以双碳目标的提出为节点,多数样本企业环境效率改善速度有所提升且其驱动力渐由技术效率转变为技术进步。

双碳背景下居民快递包装回收行为研究

在“双碳”背景下,针对目前中国快递包装回收率低的问题,利用湖南省高校学生家庭的308份调研数据,研究居民快递包装回收行为影响因素。以拓展的计划行为理论为基础,通过构建结构方程模型(structural equation model,SEM)进行验证分析,并替换不同模型,用线性回归对结果进行稳健性检验。研究结果表明:感知行为控制和低碳自我认同感对居民快递包装回收意愿的影响程度明显高于回收态度、主观规范;实施垃圾分类会显著正向调节回收意愿与回收行为之间的关系,并且实施垃圾分类的程度越高,发生快递包装回收实际行为的可能性越大。