腐蚀磨损协同作用率的研究

提出了腐蚀与磨损“协同作用率”的概念，并用于判断腐蚀与磨损协同作用的性质及大小和确定腐蚀磨损过程中材料损失的主要形式．介绍了协同作用率的测定方法，并以Ｇ１０５钢及化学镀Ｎｉ－Ｐ合金在５．０％ＮａＣｌ溶液中的腐蚀磨损作为研究对象，研究了载荷、滑动速度对腐蚀磨损协同作用的影响．结果表明：协同作用率随载荷增大而增大，随滑动速度增大而减小．

基于佣金率协同的电商导购产业链广告策略研究

本文根据以电商平台和导购平台为代表的电商导购产业链广告策略的不同,构建了四种不同的模型,求解并通过变量的比较和分析得出最优广告策略、定价和服务策略。研究表明:(1)广告策略会使导购平台服务水平和利润增加,电商平台产品价格和利润增加,随着广告投入的增加,整个电商导购产业链的竞争力也在不断增强;(2)合作广告投入决策下,广告投入最大且随着佣金率的降低,广告投入会增加;非合作广告投入决策下,随着佣金率的增加,广告投入会增加;(3)合作广告投入决策下,从短期来看广告投入、产品价格、服务水平和双方利润均最大;从长期来看双方实现了佣金率协同,因此合作广告投入是双方的最优广告策略。

一指禅推法不同作用力下上肢肌群运动方式及肌电信号特征

目的观察不同手法力量下一指禅推法上肢肌电信号特征,找出手法操作关键技术上肢肌群协同运动方式。方法采集专家组、熟练组和初学组手法肌电信号数据。每位测试者按手法力量分轻、中、重3种类型操作,选择连续稳定的数据采用MyoResearch软件进行分析。结果上肢各测试肌群肌电积分(iEMG)比较有显著差异(P<0.05);不同手法力量肌群iEMG比值比较,专家组和熟练组无显著差异(P>0.05),比值前3位为尺侧腕屈肌群、三角肌、桡侧伸肌群;手法核心主动肌群参与运动方式基本一致。初学组在不同手法力量下iEMG比值前3位肌肉群各不相同,差异较明显。专家组、熟练组和初学组之间协同收缩率比较差异均显著(P<0.01),初学组协同收缩率最大,专家组协同收缩率最小,且协同收缩率随手法力量增加逐渐下降。6 min操作三角肌肉中位频率斜率比较,专家组测试者耐疲劳度较好。结论专家组和熟练组手法肌电信号有共同特征,存在手法操作的核心肌群。上肢核心肌群运动方式具有规律性,并且iEMG比值、中位频率斜率、协同收缩率等指标可作为评价手法持久性、均匀性,以及施力方式是否规范的参考标准。

错列正弦型微通道中超临界LNG流动与换热分析

为强化液化天然气在印刷电路板式换热器(PCHE)内的换热效能,提出周期性波动强化综合换热性能的错列正弦型微通道模型并采用数值模拟方法进行验证。得到了流体温度121—345 K范围内超临界LNG在错列正弦型微通道和直通道下,热流密度、质量流量及入口压力对传热系数和摩阻因子的影响规律。此外,结合场协同原理,提出评价局部综合换热性能的参数(场协同率)并对其变化规律进行分析。研究结果表明:传热系数沿流向先增大后减小,峰值出现在准临界点;热流密度和质量流量的增加有利于传热系数的提高,而入口压力对其值的影响与温度区间有关;正弦型通道和直通道的错列排布导致摩阻因子呈周期性下降趋势;采用场协同率与PEC值评估综合换热性能结果趋于一致,且呈周期性波动变化。

Effect of WS_2 addition on electrical sliding wear behaviors of Cu-graphite-WS_2 composites

Four kinds of Cu-based composites with different mass ratios of graphite and WS2 as lubricants were fabricated by hot-pressing method. Electrical sliding wear behaviors of the composites were investigated using a block-on-ring tribometer rubbing against Cu-5%Ag alloy ring. The results demonstrated that 800 ~C was the optimum sintering temperature for Cu-graphite-WS2 dual-lubricant composites to obtain the best comprehensive properties of mechanical strength and lubrication performance. Contact voltage drops of the Cu-based composites increased with increasing the mass ratio of WS2 to graphite. The Cu-based composite with 20% graphite and 10% WS2 showed the best wear resistance due to the excellent synergetic lubricating effect of graphite and WS2. The reasonable addition of WS2 into the Cu-graphite composite can remarkably improve the wear resistance without much rise of electrical energy loss which provides a novel principle of designing suitable sliding electrical contact materials for industrial applications.

Performance of HT-PEMFC Based on Improved Baffle Structure

This study combines the three-dimensional model of the high-temperature proton exchange membrane fuel cell(HT-PEMFC)with theoretical analysis,by optimizing the structure of the fuel cell,adding a semicircular baffle in the gas channel and implementing novelly arranged obstacles to improve the PEMFC performance. The effects of velocity distribution,interface reactant concentration and pressure drop on performance are studied. The results show that adding obstacles in the gas channel will produce vertical velocity and can improve output performance,especially in the case of high current density and higher baffle radius. The superiority of the optimized structure in mass transfer capacity is proved,and a mechanism explanation is given for the improvement of performance.

Energy Saving Cooperative Communication over Fading Channels with Relay Selection and Power Control

In order to save energy and make more efficient use of wireless channel, this article puts forward an energy saving cooperative relaying scheme which actuates the cooperative transmis- sion only when the feedback from the destination indicates failure of the direct transmission. The proposed scheme selects the optimal relay and its corresponding transmission power in each time slot based on channel condition and residual ener- gy with the objective of minimizing energy con- sumption and extending network lifetime. In the study, the f＇mite-state Markov channel model is used to characterize the correlation structure of channel fading in wireless networks, and the pro- cedure of relay selection and transmission power decision is formulated as a M arkov decision process. Numerical and simulation results show that the proposed scheme consumes less energy and prolongs the network lifetime.

Synergetic Effect of Y Zeolite and ZSM-5 Zeolite Ratios on Cracking, Oligomerization and Hydrogen Transfer Reactions

The objective of this study is to explore the optimum composition of Y and ZSM-5 zeolites to develop novel catalysts for obtaining lower gasoline olefins content and higher propylene yield. Five composite zeolite catalysts with varying Y zeolite/ZSM-5 zeolite ratios have been prepared in this work to investigate the synergy between the Y zeolite and ZSM-5 zeolite on the selectivity to protolytic cracking, β-scission, oligomerization, and hydrogen transfer reactions using a FCC naphtha feedstock at 480 ℃ in a confined fluidized bed reactor. Experimental results showed that the composite catalyst with a Y zeolite/ZSM-5 zeolite ratio of 1:4 had the highest protolytic cracking and β-scission ability, which was even higher than that of pure ZSM-5 catalyst. On the other hand, the catalyst with a Y zeolite/ZSM-5 zeolite ratio of 3:2 exhibited the strongest hydrogen transfer functionality while the pure Y zeolite based catalyst had the highest oligomerization ability. For all the catalysts tested, increasing conversion enhanced the selectivity to protolytic cracking and hydrogen transfer reactions but reduced the selectivity to β-scission reaction. However, no clear trend was identified for the selectivity to oligomerization when an increased conversion was experienced.

Does Amplify-and-Forward Cooperative Relay Improve OFDM/OFDMA Ergodic Capacity？

The ergodic information rate for Orthogonal Frequency-Division Multiplexing / Orthogonal Frequency-Division Multiple Access with amplify-and-forward （AF） relaying systems in the presence of frequency offsets is evaluated. Unlike previous work, per-subcarrier adaptive power allocation is performed on each relay to optimize the system ergodic information rate. For a given frequency offset and total number of relays M, the AF ergodic information rate is proven to be a monotonically increasing function of α （the ratio of the power allocated to the source node and the total transmit power）, implying that the maximum ergodic information rate can be obtained at α=1 （i.e., there is no cooperative relay）. Furthermore, the proof of ＂cooperative relays cannot improve the AF ergodic information rate in a quasi-static wireless channel＂ is also provided in this letter.

A cooperative user selection scheme based on energy efficiency and interference factor in cooperative communication systems

With the rapid development of green communications,energy consumption issue plays more and more important role in cooperative communication strategies and communication systems.Based on cooperative transmission model,a cooperative user selection scheme is proposed in consideration of both energy efficiency and interference factor.With the proposed scheme,the selected cooperative user consumes less energy and receives less interference.Furthermore,the main factor is analyzed to affect system performance,including signal-to-noise ratio(SNR)of source user and cooperative user,distance between source user and cooperative user or base station(BS),and fading factor in the transmission model.Through the proposed scheme,energy consumption and influence of interference are jointly taken into account during the cooperative user selection process.Besides,bit error rate(BER)in proposed scheme is also superior to existing schemes.Simulation results are presented to show the performance improvement of the proposed scheme.

Power allocation and mode selection methods for cooperative communication in the rectangular tunnel

For the multipath fading on electromagnetic waves of wireless communication in the confined areas,the rectangular tunnel cooperative communication system was established based on the multimode channel model and the channel capacity formula derivation was obtained.On the optimal criterion of the channel capacity,the power allocation methods of both amplifying and forwarding(AF) and decoding and forwarding(DF) cooperative communication systems were proposed in the limitation of the total power to maximize the channel capacity.The mode selection methods of single input single output(SISO) and single input multiple output(SIMO) models in the rectangular tunnel,through which the higher channel capacity can be obtained,were put forward as well.The theoretical analysis and simulation comparison show that,channel capacity of the wireless communication system in the rectangular tunnel can be effectively enhanced through the cooperative technology;channel capacity of the rectangular tunnel under complicated conditions is maximized through the proposed power allocation methods,and the optimal cooperative mode of the channel capacity can be chosen according to the cooperative mode selection methods given in the paper.

Prediction and mechanistic analysis of May precipitation in North China based on April Indian Ocean SST and the Northwest Pacific Dipole

North China May precipitation(NCMP)accounts for a relatively small percentage of annual total precipitation in North China,but its climate variability is large and it has an important impact on the regional climate and agricultural production in North China.Based on observed and reanalysis data from 1979 to 2021,a significant relationship between NCMP and both the April Indian Ocean sea surface temperature(IOSST)and Northwest Pacific Dipole(NWPD)was found,indicating that there may be a link between them.This link,and the possible physical mechanisms by which the IOSST and NWPD in April affect NCMP anomalies,are discussed.Results show that positive(negative)IOSST and NWPD anomalies in April can enhance(weaken)the water vapor transport from the Indian Ocean and Northwest Pacific to North China by influencing the related atmospheric circulation,and thus enhance(weaken)the May precipitation in North China.Accordingly,an NCMP prediction model based on April IOSST and NWPD is established.The model can predict the annual NCMP anomalies effectively,indicating it has the potential to be applied in operational climate prediction.

外周血CEA、ATER及CTCs对晚期肺腺癌患者化疗效果及预后的评估价值分析

目的:探究外周血癌胚抗原(CEA)、协同肿瘤红细胞花环率(ATER)及外周血循环肿瘤细胞(CTCs)对晚期肺腺癌患者化疗效果及预后的评估价值。方法:回顾性分析2015年1月-2018年5月抚州市第一人民医院肿瘤科收治的127例晚期肺腺癌患者的临床资料,患者均进行2个周期化疗。将患者根据化疗效果分为CR组(n=20)、PR组(n=46)、SD组(n=37)、PD组(n=24)。比较不同化疗效果患者外周血CEA、ATER及CTCs差异;使用Spearman法分析患者外周血CEA、ATER与晚期肺腺癌患者化疗效果的相关性。全部晚期肺腺癌患者均随访3年,根据患者是否死亡分为存活组(n=49)、死亡组(n=78),比较不同预后结局晚期肺腺癌患者外周血CEA、ATER及CTCs差异,使用受试者特征(ROC)曲线分析晚期肺腺癌患者外周血CEA、ATER及CTCs对死亡结局的预测效能。结果:不同化疗效果患者外周血CEA、ATER及CTCs比较,差异均有统计学意义(P<0.05)。Spearman分析结果显示,晚期肺腺癌患者外周血CEA与患者化疗效果正相关(r_(s)=0.871,P<0.05),外周血ATER与患者化疗效果负相关(r_(s)=-0.889,P<0.05)。存活组患者外周血CEA水平、CTCs阳性率均低于死亡组,外周血ATER水平高于死亡组(P<0.05)。ROC曲线结果显示,外周血CEA、ATER及CTCs预测晚期肺腺癌患者死亡结局的AUC分别为0.814、0.937、0.641(P<0.05)。结论:外周血CEA、ATER及CTCs均可用于晚期肺腺癌患者的化疗效果评估及预后预测。

圆管管束特性试验及协同分析

为分析前排绕流扰动对后排管换热及阻力的影响规律，以4列多排（2～10）管束为研究对象，建立稳定的热态流场，采用错列及顺列2种方式，分析传热及流动特性在不同管排数下的变化规律；定量分析管排数对阻力特性的影响规律，定义了管排阻力修正系数，并根据实验数据给出了其在不同管排数下的取值；根据场协同理论定义了相对场协同率的概念，用以表征不同管排数下其总体换热效率相对实际最大换热的比值。研究结果表明，管间绕流为管束换热器管排影响规律的主要原因，10排及以上管束流场均匀，管间绕流影响最小，场协同角较小，10排以内采用管排系数进行修正。

Energy Efficiency Analysis of Cellular Networks with Cooperative Relays via Stochastic Geometry

Cooperative relaying is a promising technology that can improve the spectral and energy efficiency of cellular networks. However, the deployed relays consume a lot of energy and system resources. To improve the energy efficiency of the relay-assisted cellular networks, this paper considers the use of energy harvesting(EH) on relay nodes. A random sleeping strategy is also introduced in macro base stations(MBS) as a possible method to reduce energy consumption. In this paper, an analytical model is proposed to investigate the energy efficiency of cellular networks with EH relays and sleep mode strategy. Numerical results confirm a significant energy efficiency gain of the proposed networks comparing to the cellular networks with non-EH relays and MBSs without sleep mode strategy. The effects of the density and transmit power of MBSs on energy efficiency are also given through simulations.

Expression and correlation of Ezrin and survivin in non-small cell lung cancer

Objective: The aim of this study was to explore expression and correlation of Ezrin and survivin in non-small cell lung cancer (NSCLC). Methods: Expression of Ezrin and survivin were detected and analyzed by Envision method of immu- nohistochemical staining in 86 NSCLC. Results: The strong expression rate of Ezrin in NSCLC was 60.5% and significantly correlated with lymph node metastasis (P < 0.05), but no associated with gender, histologic subtype, TNM stages, differen- tiation and smoking. Meanwhile, the positive expression rate of survivin in NSCLC was 65.1% and significantly correlated with TNM stages and lymph node metastasis (P < 0.05), but no associated with gender, histologic subtype, differentiation and smoking. And expression of Ezrin and survivin were positively correlated in NSCLC (r = 0.384). Conclusion: Ezrin and survivin may play synergetic roles in the process of carcinogenesis of NSCLC, and their expression may be significantly associated with NSCLC metastasis. Detection of Ezrin and survivin may be valuable for diagnosing lung cancer metastasis and providing evidence for clinical treatment.

Cooperative detection algorithm of spectrum holes in cognitive radio

To improve the detection performance of sensing users for primary users in the cognitive radio, an optimal cooperative detection algorithm for many sensing users is proposed. In this paper, optimal decision thresholds of each sensing user are discussed. Theoretical analysis and simulation results indicate that the detection probability of optimal decision threshold rules is better than that of determined threshold rules when the false alarm of the fusion center is constant. The proposed optimal cooperative detection algorithm improves the detection performance of primary users as the attendees grow. The 2 dB gain of detection probability can be obtained when a new sensing user joins in, and there is a 17 dB improvement when the accumulation number increases from 1 to 50.

Cooperative Anti-Interference Spectrum Sharing with Secondary User Selection

In this paper, we propose a cooperative anti-interference spectrum sharing strategy with secondary user selection where the secondary system can gain spectrum access along with the primary system. Specifically, secondary user and are selected to transmit the primary and secondary signal through different bandwidth in the second transmission slot which occupies fraction of the time. Thus, the primary and secondary systems will not interfere with each other. We study the joint optimization of time and bandwidth allocation such that the transmission rate of the secondary system is maximized, while guaranteeing the primary system to achieve its target rate. Simulation results confirm efficiency of the proposed spectrum sharing strategy, and the significant performance improvement of the cognitive system.

The efficacy of capecitabine and temozolomide against neuroendocrine carcinomas

Objective Neuroendocrine carcinomas(NECs) are resistant to currently available chemotherapy agents, and its therapeutic options are limited. Preclinical data have suggested synergy between capecitabine and temozolomide(CAPTEM). Therefore, we evaluated the efficacy and safety of CAPTEM in patients with metastatic NECs who have failed prior therapies.Methods A retrospective review was conducted on seven patients with metastatic NECs for whom platinum-based chemotherapies and hepatic chemoembolization failed. Patients received capecitabine(1000 mg twice daily on days 1-14) and temozolomide(150–200 mg/m^2 once daily on days 10–14) every 28 days. Tumor assessments were performed every two cycles.Results Among the seven patients treated, two achieved partial remission and four achieved stable disease. The total response rate was 29%, and the clinical benefit was 86%. Median progression-free survival was 10(range: 8–14) months. The most common toxicities were grade 1 and 2 neutropenia, grade 1 fatigue, and grade 1 and 2 hand-foot syndrome. No grade 4 toxicities or treatment-related deaths were observed.Conclusion Our study showed that the CAPTEM regimen is an effective and well-tolerated salvage option for NECs. Further prospective studies are warranted to evaluate optimal combinations of the CAPTEM regimen for NECs.

Cooperative Voltage Control Method by Residential PV Systems in Distribution System

Recently, the number of system interconnection of the renewable energy such as PV （photovoltaic） generation system and wind power generation system has been increasing drastically. A distribution system with the distributed generation must be operated keeping reliability of power supply and power quality. When high-capacity PV systems are interconnected to the distribution system, the system voltages may be deviated from the upper limit or lower limit of proper voltage in the distribution system. In this study, the authors propose a cooperative voltage control method of the distribution system by the power factor control of plural residential PV systems. In order to verify the validity of the proposal method, the numerical calculations are carried out by using an analytical model of distribution system which interconnected residential PV systems.