Two-step strategy—conjunctival flap covering surgery combined with secondary deep anterior lamellar keratoplasty for the treatment of high-risk fungal keratitis

AIM:To investigate whether the two-step strategy[conjunctival flap covering surgery(CFCS)combined with secondary deep anterior lamellar keratoplasty(DALK)]is effective for patients with high-risk fungal keratitis(FK).METHODS:In this noncomparative,retrospective case series,10 subjects(6 males,4 females)with a mean age of 56.5±7.1(range 47-72)y with high-risk FK undergone the two-step strategy were included.Reported outcome measures were healing of the corneal ulcer,recurrence of FK,reject reaction,improvement in best corrected visual acuity(BCVA)and relevant complications.RESULTS:The average diameter of corneal infiltrates was 7.50±0.39 mm,ranging from 6.94 to 8.13 mm.The mean depth of corneal infiltrates was 422.4±77.1μm,ranging from 350 to 535μm.The mean corneal thickness was 597.4±117.3μm,ranging from 458 to 851μm.Hypopyon and endothelial plaques were presented in all patients.The period between the two steps was 3.65±0.9(ranging from 3 to 5)mo.The graft diameter was 7.75±0.39 mm.At the last follow-up(average 9.25±3.39,ranging from 5.5 to 17mo),no fungal recurrence or graft rejection appeared,and all patients showed improvement of BCVA.One patient suffered from liver function impairment due to oral voriconazole for 4wk and recovered spontaneously after 1wk of drug withdrawal.CONCLUSION:The two-step strategy is safe and effective in the treatment of high-risk FK by transforming intentional therapeutic penetrating keratoplasty during acute infection to later optical DALK.It is a practical strategy,especially in areas lacking fresh donor corneas and eye bank services.

Optimal guidance strategy for flexible load based on hybrid direct load control and time of use

The time-of-use(TOU)strategy can effectively improve the energy consumption mode of customers,reduce the peak-valley difference of load curve,and optimize the allocation of energy resources.This study presents an Optimal guidance mechanism of the flexible load based on strategies of direct load control and time-of-use.First,this study proposes a period partitioning model,which is based on a moving boundary technique with constraint factors,and the Dunn Validity Index(DVI)is used as the objective to solve the period partitioning.Second,a control strategy for the curtailable flexible load is investigated,and a TOU strategy is utilized for further modifying load curve.Third,a price demand response strategy for adjusting transferable load is proposed in this paper.Finally,through the case study analysis of typical daily flexible load curve,the efficiency and correctness of the proposed method and model are validated and proved.

Optimization of Sporulation Conditions of Biocontrol Bacteria B579 by Two-step Control Strategy

[Objective] For preparing the biopesticide of Bacillus subtilis B579 with high spore concentration,the sporulation conditions were optimized.[Method] Two-step fermentation control strategy was used,in which,the first phase（0-10 h）was to improve cell growth,and the second phase（10-30 h）was to promote spore formation.Four factors including initial glucose concentration,fermentation pH,temperature（in the second phase）and shaking speed（in the second phase）were optimized using the methods of single factor test and orthogonal experiment.[Result] The initial glucose concentration showed a significant effect on sporulation.The optimal conditions for the spore formation of B.subtilis B579 were as follows：initial glucose concentration 5 g/L,fermentation pH 7.0,the temperature for the first phase 37 ℃,and the shaking speed for the first phase 180 r/min,the temperature for the second phase 40 ℃,and the shaking speed for the second phase 200 r/min;in addition,the first phase was 10 h and the second phase of fermentation was conducted for 30 h.Under such conditions,the spore concentration and spore formation rate could reach 9.43×108 CFU/ml and 90.99%,respectively,which represented 6.70-fold and 2.43-fold increase compared with those before optimization.[Conclusion] The spores concentration of biocontrol agent was improved using two-step control strategy,which provided the basis for biopesticide production in large scale.

A two-step quantum secure direct communication protocol with hyperentanglement

We propose a two-step quantum secure direct communication （QSDC） protocol with hyperentanglement in both the spatial-mode and the polarization degrees of freedom of photon pairs which can in principle be produced with a beta barium borate crystal. The secret message can be encoded on the photon pairs with unitary operations in these two degrees of freedom independently. This QSDC protocol has a higher capacity than the original two-step QSDC protocol as each photon pair can carry 4 bits of information. Compared with the QSDC protocol based on hyperdense coding, this QSDC protocol has the immunity to Trojan horse attack strategies with the process for determining the number of the photons in each quantum signal as it is a one-way quantum communication protocol.

The Security Analysis of Two-Step Quantum Direct Communication Protocol in Collective-Rotation Noise Channel

To analyze the security of two-step quantum direct communication protocol （QDCP） by using Einstein-Podolsky Rosen pair proposed by Deng et al. [Phys. Rev. A 68 （2003）042317] in collective-rotation noise channel, an excellent model of noise analysis is proposed. In the security analysis, the method of the entropy theory is introduced, and is compared with QDCP, an error rate point Qo（M ： （Q0, 1.0）） is given. In different noise levels, if Eve wants to obtain the same amount of information, the error rate Q is distinguishable. The larger the noise level ~ is, the larger the error rate Q is. When the noise level ~ is lower than 11%, the high error rate is 0.153 without eavesdropping. Lastly, the security of the proposed protocol is discussed. It turns out that the quantum channel will be safe when Q 〈 0.153. Similarly, if error rate Q〉 0.153 = Q0, eavesdropping information I 〉 1, which means that there exist eavesdroppers in the quantum channel, and the quantum channel will not be safe anymore.

Antenna geometry strategy with prior information for direction-finding MIMO radars

The antenna geometry strategy for direction finding （DF） with multiple-input multiple-output （MIMO） radars is studied. One case, usually encountered is practical applications, is consi- dered. For a directional antenna geometry with a prior direction, the trace-optimal （TO） criterion （minimizing the trace） on the av- erage Cramer-Rao bound （CRB） matrix is employed. A qualitative explanation for antenna geometry is provided, which is a combi- natorial optimization problem. In the numerical example section, it is shown that the antenna geometries, designed by the proposed strategy, outperform the representative DF antenna geometries.

A hybrid specific index-related process monitoring strategy based on a novel two-step information extraction method

A two-step information extraction method is presented to capture the specific index-related information more accurately.In the first step,the overall process variables are separated into two sets based on Pearson correlation coefficient.One is process variables strongly related to the specific index and the other is process variables weakly related to the specific index.Through performing principal component analysis(PCA)on the two sets,the directions of latent variables have changed.In other words,the correlation between latent variables in the set with strong correlation and the specific index may become weaker.Meanwhile,the correlation between latent variables in the set with weak correlation and the specific index may be enhanced.In the second step,the two sets are further divided into a subset strongly related to the specific index and a subset weakly related to the specific index from the perspective of latent variables using Pearson correlation coefficient,respectively.Two subsets strongly related to the specific index form a new subspace related to the specific index.Then,a hybrid monitoring strategy based on predicted specific index using partial least squares(PLS)and T2statistics-based method is proposed for specific index-related process monitoring using comprehensive information.Predicted specific index reflects real-time information for the specific index.T2statistics are used to monitor specific index-related information.Finally,the proposed method is applied to Tennessee Eastman(TE).The results indicate the effectiveness of the proposed method.

Simulation Study of the Control Strategy of a DC Inverter Heat Pump Using a DC Distribution Network

Photovoltaics,energy storage,direct current and flexibility(PEDF)are important pillars of achievement on the path to manufacturing nearly zero energy buildings(NZEBs).HVAC systems,which are an important part of public buildings,play a key role in adapting to PDEF systems.This research studied the basic principles and operational control strategies of a DC inverter heat pump using a DC distribution network with the aim of contributing to the development and application of small DC distribution systems.Along with the characteristics of a DC distribution network and different operating conditions,a DC inverter heat pump has the ability to adapt to changes in the DC bus voltage and adds flexibility to the system.Theoretical models of the DC inverter heat pump integrated with an ice storage unit were developed.The control strategies of the DC inverter heat pump system considered the influence of both room temperature and varied bus voltage.A simulation study was conducted using MATLAB&Simulink software with simulation results validated by experimental data.The results showed that:(1)The bus fluctuation under the rated working voltage had little effect on the operation of the unit;(2)When the bus voltage was fluctuating from 80%-90%or 105%-107%,the heat pump could still operate normally by reducing the frequency;(3)When the bus voltage was less than 80%or more than 107%,the unit needed to be shut down for the sake of equipment safety,so that the energy storage device could adjust to the sharp decrease or rise of voltage.

中国水层CO_(2)地质封存技术攻关方向

在国家“碳达峰碳中和”战略目标下,为了延长化石能源行业的生命周期,亟需进行大规模碳减排的重大革命,其中CO_(2)地质封存(CCS)这一大规模碳减排的托底技术,已在全球达成共识。为此,系统梳理了全球CCS发展趋势,并针对中国CCS地质特点和工程技术现状,分析了中国发展水层CCS面临的挑战和难点,提出了中国水层CO_(2)地质封存技术的攻关方向。研究结果表明:①中国水层CCS起步早,当前正在开展世界级规模水层CCS先导试验,技术水平与国外并行,CCS有望成为中国未来大规模碳减排的主要手段;②鉴于中国水层多无法回避陆相沉积、断裂发育、非均质性强等先天条件,中国未来建设大规模水层CCS将面临封存规模大、封存成本高和长期封存安全性等3个方面关键技术的挑战;③从推动和形成CCS负碳新产业角度,中国未来水层CCS碳埋存需要攻克CCS地质体评估、CO_(2)高速注入、低浓度CO_(2)封存、降低成本和地质监测等5个关键技术。结论认为,该研究认识进一步坚定了中国发展水层CCS技术的信心,提出的5个方面关键技术为快速形成负碳领域的国家战略科技力量明确了攻关方向,同时为后续推动大规模地下储氢、储氦、压缩空气储能等战略性新兴行业的发展提供了前瞻性技术支撑。

新时代职业教育服务国家重大战略的价值向度

新时代背景下,职业教育的战略功能就是其服务国家战略的能力,不同层次的职业教育在服务国家重大战略上各自具有独特的价值意义。服务国家战略是新时代职业教育发展的内在要求,服务国家现代化发展、实现职业教育内涵式发展、深化职业教育实践性发展是职业教育服务国家重大战略的三个基本价值向度。要着重把握新时代职业教育服务国家战略的功能表现形态,并在技术技能人才培养、产业对接与技术创新、职教文化传承等关键领域主动融入国家战略并准确把握自身定位,有效提升服务国家重大战略的能力和质量。

方坯直轧工艺下连铸坯温度场均匀性及切坯工艺优化

对方坯直轧工艺下连铸坯温度场和初生晶粒演化进行数值模拟,并根据计算结果对连铸坯切坯顺序进行优化。结果表明:随着连铸拉速的提高,连铸方坯表面温度和心表温差逐渐增大,心部等轴晶区也逐渐扩大;拉速对连铸坯初生晶粒取向的影响较小;连铸坯定尺对铸坯头尾温差的影响较大,在拉速不变的情况下,连铸坯定尺每增加1 m,头尾温差增大约10.5℃。方坯直轧工艺生产采用非定尺切坯策略,可以有效减小连铸拉速波动对出坯生产节奏的影响。

二冲程半直喷航空发动机喷油策略研究

基于自主研发的二冲程低压半直喷航空发动机及控制系统,开展喷油控制策略及对发动机性能影响规律的研究。结果表明:对于不同的发动机运行工况,需要采取不同的喷油策略组合。在起动和怠速工况,采用进气道喷射的独立供油方式;在部分负荷及高负荷工况,采用进气道喷射和缸内直喷协同供油方式,随着发动机直喷比例的提高,燃油消耗率相应减小;与采用进气道喷射供油相比较,采用低压半直喷供油可以获得较理想的燃油经济性。

黄河河口治理战略实践及其研究综述

基于“战略”一词的概念定义,将黄河河口的综合治理归纳为防洪减灾安全、流路科学运用、泥沙调控处理、河流供给均衡、生态系统健康、人地系统协调发展等六大战略;系统梳理了各战略在河口治理中的实践历程和研究进展,总结分析各战略研究的适应性与局限性;在此基础上提出了今后开展黄河河口治理战略研究的主导方向。

基于IGCT抑制换相失败的关键控制策略

针对基于电网换相换流器的高压直流(LCC-HVDC)输电系统因以晶闸管作为换流器件而存在的换相失败问题,以集成门极换流晶闸管(IGCT)在中国某背靠背高压直流工程中的应用为基础,首先介绍了IGCT型高压直流的拓扑及基本运行原理。接着,从兼顾换相失败抵御效果和IGCT阀的关断应力角度,提出了适应IGCT阀的关断策略。在此基础上,研究了不同类型交流故障对故障电流峰值的影响,提出了利用故障扰动系数动态调整电流控制器参数的策略,实现故障电流抑制和故障期间直流功率的稳定输送。最后,通过实时数字仿真(RTDS)验证了所提策略的正确性和有效性。

聚甲氧基二甲醚和汽油双燃料火花辅助压燃燃烧及排放试验研究

试验平台基于汽油缸内直喷(gasoline direct injection,GDI)发动机改造,缸内直喷聚甲氧基二甲醚(polyoxymethylene dimethyl ether,PODE),进气道喷射汽油,并将压缩比从10提升至15以利于压燃,以点火和直喷策略作为控制参数,获取双燃料火花辅助压燃(dualfuel spark-assisted compression ignition,DF-SACI)发动机的运行特征。试验结果表明:DFSACI呈现多阶段放热,直喷正时提前可提高混合气均匀性,减小不同燃烧阶段的界限,放热率明显提高;直喷比例可以更为有效地调节CA50和等容燃烧的比例,对热效率影响明显;同时放热率受点火正时提前的影响最小。试验中有效热效率最高可达37.5%。排放方面,DFSACI模式在合适的点火和喷射策略下,可在一定程度上降低HC和CO的排放,HC体积分数可降低至3000×10^(-6)以下,CO体积分数可降低至1500×10^(-6)以下,同时将NOx排放控制在较低水平。通过对燃烧策略的合理调整,PODE/汽油双燃料发动机借助火花辅助压燃可实现高效清洁燃烧。

递进式融合多策略的改进哈里斯鹰优化算法

针对哈里斯鹰优化算法(HHO)易陷入局部最优、全局探索性能与局部开发能力不平衡等缺点,提出递进式融合多策略的改进哈里斯鹰优化算法(IHHO).首先,调整随机游走机制的位置更新方程以实现小范围优质勘探,提升该机制有效性,加强算法局部开发能力;其次,采用S型自适应能量控制因子,使算法能根据搜索进程合理调控捕猎行为,修正寻优模型;最后,融入定点重组与诱变策略,既保证种群优良基因集中于某一个体,又丰富种群多样性,算法局部寻优性能和局部极值规避能力并进增强.实验表明,所提改进方法以递进式提升算法性能,经耦合叠加效应后所得IHHO的搜索精度高、收敛速度快,并且具有较强实用性.

新型船舶中压直流固态断路器拓扑分析与设计

为解决船舶中压直流(medium voltage direct current,MVDC)电力系统直流电流开断困难,以及发生短路时故障电流上升率高且峰值大的问题,提出一种基于耦合电抗器的阻容限流型固态直流断路器拓扑。以晶闸管(silicon controlled rectifier,SCR)作为主开断器件,通过耦合电抗器来辅助晶闸管开断,并在直流系统发生故障时,通过换流过程将阻容限流元件接入,有效限制故障电流上升率和峰值,减少故障开断所需时间。基于所提拓扑设计了6 kV/4.2 kA的直流断路器模型,在PSCAD/EMTDC中进行仿真,并与现有拓扑进行对比分析。仿真结果表明:所设计断路器可针对直流系统不同的运行状态,按照不同的控制策略顺利完成对直流电流的开断,并且在开断速度、限流能力和金属氧化物避雷器(metal oxide arrester,MOA)耗能方面均具有一定优势。

英语阅读中词义推测策略的教学研究

词义推测策略是依靠阅读间接或附带习得词汇过程中至关重要的方法。文章通过有关推测词义策略的直接词汇教学,探讨教学对二语词义推测能力的影响。研究以75名英语专业一年级本科生为实验对象,并将其分为控制组和实验组。经过对实验组的相关教学,比较实验组与控制组以及实验组内的词义推测能力,结果显示:(1)在教学干预后的实验组推测词义的均值显著高于控制组;(2)教学干预后实验组推测词义的均值显著高于干预前的均值。结果表明,推测词义策略的直接词汇教学有助于大学英语学习者阅读中推测词义的能力提高。

直喷汽油机高效颗粒捕集器技术及控制策略研究

为了适应国家排放法规对汽油直喷发动机颗粒物监测粒径逐渐减小的要求,根据汽油直喷发动机排放开发目标,设计不同的汽油机颗粒捕集器(GPF)技术方案,通过发动机台架试验、转毂试验的测试选型确定捕集效率高、背压小的最优方案。建立了基于发动机原排和压差的GPF控制策略,结合GPF测试选型数据标定GPF碳载量模型、再生效率模型等,实现再生工况识别并协调再生控制。通过WLTC排放循环验证GPF控制策略,最优方案的捕集效率满足排放开发目标,有效降低了汽油直喷汽油机的颗粒物排放。

基于改进帝王蝶算法的最大似然DOA估计

针对传统最大似然波达方向(maximum likelihood direction of arrival,ML-DOA)估计存在计算量大、估计精度差等问题,本文提出一种采用改进帝王蝶优化算法(improved monarch butterfly optimization algorithm,IMBO)的ML-DOA估计方法。IMBO算法通过精英反向学习策略对初始帝王蝶种群进行优化,得到适应度值较优的初始帝王蝶个体,进而能够改善帝王蝶种群的多样性;引入差分进化算法启发的变异操作以及自适应策略对帝王蝶个体的寻优方式进行改进,扩大了算法的搜索空间;引入了高斯-柯西变异算子,自适应调整变异步长,避免算法陷入局部最优。将IMBO应用于ML-DOA,实验表明,与传统的DOA估计算法相比,在不同信源数目、信噪比以及种群数量下,本文提出的算法收敛性能更好,均方根误差更低,运算量更小。