Recent progress in CO oxidation over Pt-group-metal catalysts at low temperatures

CO oxidation is probably the most studied reaction in heterogeneous catalysis.This reaction has become a hot topic with the discovery of nanogold catalysts,which are active at low temperatures（at or below room temperature）.Au catalysts are the benchmark for judging the activities of other metals in CO oxidation.Pt-group metals（PGMs） that give comparable performances are of particular interest.In this mini-review,we summarize the advances in various PGM（Pt,Pd,Ir,Rh,Ru）catalysts that have high catalytic activities in low-temperature CO oxidation arising from reducible supports or the presence of OH species.The effects of the size of the metal species and the importance of the interface between the metal and the reducible support are covered and discussed in terms of their promotional role in CO oxidation at low temperatures.

GROUP VELOCITY CONTROL SCHEME WITH LOW DISSIPATION

In order to prevent smearing the discontinuity, a modified term is added to the third order Upwind Compact Difference scheme to lower the dissipation error. Moreover, the dispersion error is controled to hold back the non physical oscillation by means of the group velocity control. The scheme is used to simulate the interactions of shock density stratified interface and the disturbed interface developing to vortex rollers. Numerical results are satisfactory.

Lithofacies Characters and Significance of the Submarine Fan of the Liufengguan Group in Qinling

Field investigation and laboratory research on flysch of the Liufengguan Group in Qinling indicate the following： （1） Sandstone of the Liufengguan Group is categorized as feldspathic lithic graywacke with a minor amount of lithic graywacke in the QFR triangular diagram. Grain size〈0.3 mm. Bedding plane structures such as groove casts and suspected flute casts can be found at the bottom of the sandstone. It is inferred that currents may have come from the southeast during deposition. Bedding structures such as ripple marks, graded bedding, parallel bedding, small-scale cross bedding, climbing bedding, suspected convolute bedding, microlamination and sliding structures have also been observed, which are of indicative significance. It is thought that the Liufengguan Group has the sedimentary characteristics of bedding, bedding plane structures and lithologicai assemblages of deep-sea low-density turbidity current deposits. The vertical succession of the Bouma sequence in the inner fan subfacies zone is generally incomplete： the assemblage of Ta and Tabc is commonly seen; the succession of the middle fan subfacies zone is relatively complete; and divisions Te and Tb are common in the outer fan subfacies zone. （2） The flysh of the Liufengguan Group is a sequence of deep-sea argillaceous-arenaceous submarine fan deposits, in which the authors recognize the inner, middle and outer fan subfacies and also nine types of lithofacies： normal graded sandstone （A1）, medium- to thick-bedded, fine-grained sandstone （A2）, medium- to thick-bedded and massive siltstone （A3）, thin-bedded, fine-grained sandstone and mudstone （B1）, irregular interbeds of thinbedded, fine-grained sandstone and siltstone （B2）, thin-bedded, fine-grained sandstone （C1）, very thin-bedded, fine-grained sandstone （D1）, olistostromes （El） anddeep-sea mudstone （F）. The inner fan consists of four microfacies： natural levee （A1）, water channel （A2, A3） and olistostrome （El）; in the middle fan there also occur four microfacies, i.e., branch channel （B1）, branch channel （B2）, interdistributary bay （D1） and olistostrome. The outer fan is made up of the branch channel （C1） and sheet sand （D1） microfacies, which alternate vertically with sediments of deep-sea plain subfacies （F）. There occur fining- and thinning-upward channel deposits in the outer-fan subfacies zone of the submarine fan of the Liufengguan Group observed in this study. The quartz content of the graywacke of the deposits is all higher than 40% and may reach as high as 60%. Therefore, on the basis of the aforementioned features, this flysh should be formed in a passive continental-margin tectonic environment.

IDMA based MAI mitigation scheme with low complexity and low latency

High complexity and high latency are key problems for multiuser detection （MUD） to be applied to a mobile station in cellular networks. To tackle these problems, an interleave division multiple access （IDMA） based multiple access scheme, grouped spread IDMA （GSIDMA）, is proposed. In a GSIDMA system, lower complexity and latency for mobile stations can be achieved by appropriately dividing active users into different groups. The system model of GSIDMA is constructed and followed by analysing on its system capacity, complexity and latency, and bit error rate （BER） performance. The extrinsic information transfer （EXIT） chart is used to analyze the convergence behavior of the iteration process. The grouping method and interleavers-reuse issue for GSIDMA are also discussed preliminarily. The analyses and simulation results indicate that the complexity and latency of the proposed scheme are much lower than those of IDMA, whereas its BER performance is close to the latter. The properties of low complexity and low latency make it more feasible for the practical implementation.

Use of Low Radioactive Rare-earth Waste for Sewage Treatment

Low radioactive rare earth waste (containing 232 Th,specific activity 5 000 8 000 Bq·kg -1 ) were diluted 20 times by cement,sand and carbide ash and were made into special cement.The radioactivity of this special cement complied with the healthy protect standard for radioactive materials (GB6566 86).Test results showed that this special cement could lower COD,the degradation rate increased as the time went on.In acidic medium,this special cement could remove E Coli effectively.Applying aeration and adding lumps of cement,the degradation of COD versus time complied with Logistic model through fitting by computer.The two “S” curves indicated that aeration and adding lumps of cement had synergistic action on sewage treatment.

Grouping pilot allocation scheme based on matching algorithm in massive MIMO system

Pilot allocation is one of the effective means to reduce pilot pollution in massive multiple-input multiple-output(MIMO)systems.The goal of this paper is to improve the uplink achievable sum rates of strong users,and ensure the quality of service(QoS)requirements of weak users at the same time,so that the sum rates of system can be improved.Combining with the technical advantage of pilot grouping,a low complexity pilot allocation scheme based on matching algorithm is proposed,which divides the users in the target cell into weak user group and strong user group,and adopts the minimum-maximum matching method to allocate pilots in weak user group.Through the introduction of Hungarian algorithm,a pilot allocation method is designed to ensure the fairness of the strong users.The simulation results show that,compared with the smart pilot allocation scheme,the pilot allocation scheme based on Hungarian algorithm,the pilot allocation scheme based on user grouping and the random pilot allocation scheme,the system performance of the proposed scheme has been effectively improved.

Uniquely Decomposable Constellation Group-Based Sparse Vector Coding for Short Packet Communications

Sparse vector coding(SVC)is emerging as a potential technology for short packet communications.To further improve the block error rate(BLER)performance,a uniquely decomposable constellation group-based SVC(UDCG-SVC)is proposed in this article.Additionally,in order to achieve an optimal BLER performance of UDCG-SVC,a problem to optimize the coding gain of UDCG-based superimposed constellation is formulated.Given the energy of rotation constellations in UDCG,this problem is solved by converting it into finding the maximized minimum Euclidean distance of the superimposed constellation.Simulation results demonstrate the validness of our derivation.We also find that the proposed UDCGSVC has better BLER performance compared to other SVC schemes,especially under the high order modulation scenarios.

胺基改性壳聚糖吸附材料的制备及其对铀的吸附性能研究

研究了采用水热法制备壳聚糖微球(HTCC),再通过环氧化-胺化改性法制备胺基改性壳聚糖吸附材料(AHTCC)并用于吸附废水中的低浓度铀。利用红外光谱仪、元素分析仪、热重分析仪等对AHTCC的结构、组分和热稳定性进行表征,并考察了AHTCC对铀的吸附、解吸性能。结果表明:在pH=5~8条件下,AHTCC对溶液中铀的吸附效果较好;铀吸附平衡质量浓度为120 mg/L左右时,吸附量达最大,为151.6 mg/g;铀吸附速率在反应最初60 min较快,180 min时达到吸附平衡;以80 g/L Na_(2)CO_(3)+20 g/L NaHCO_(3)作解吸剂,铀解吸率为97.5%;对于含杂离子浓度较高的实际含铀废水,经AHTCC单次吸附,铀的去除率可达95.6%。

COMPUTER SIMULATION FOR AN ULTRA-LOW RANGE SIDELOBE PULSE COMPRESSION SCHEME

A canceling range sidelobes scheme has been suggested by Yang Guangzheng, et al.,(1997) this technology is based on the fact that all sidelobe of group correlation function of ideal sets are zero. At first, this paper gives the best ideal sets (i. e. the best biphase code sets whose maximal sidelobe not more than 2) for all code length N≤12, which have been obtained from binary sequences by means of the best codes sieving method suggested by Yang Guangzheng, et al.(1997) Computer simulation for group correlation property of best ideal sets for code length N=12 on various conditions is made. Simulation result shows that the sidelobe level of best ideal set with no weighting is zero, under condition of zero-Doppler shift and has ultra-low sidelobe on Doppler up to 5kHz with no weighting and whose tolerance of phase and amplitude distortion is bigger too.

DRG支付方式下公立医院特殊病例住院费用影响因素分析

目的:分析DRG支付方式下,包括高倍率病例和低倍率病例在内的特殊病例费用特征及其影响因素,为降低医疗费用、减轻患者负担和完善DRG支付方式改革提供参考。方法:选取某三甲综合医院2022年全年所有特殊病例的病案首页数据,采用描述性分析和单因素分析对特殊病例的影响因素进行分析,并通过结构方程模型分析各影响因素间的作用路径和影响程度。结果:纳入高倍率病例1281例(占总病例2.78%),其中治疗费用花费最多(占16.29%),费用最少的是诊察费(占0.79%);低倍率病例3266例(占7.09%),其中手术费用花费最多(占31.51%),费用最少的是诊疗费(占1.61%)。性别、年龄、住院天数、科室类别、医保付费方式、并发症均是特殊病例住院费用的影响因素(P<0.05)。结构方程模型结果显示,科室类别对费用的影响最大,性别对费用的影响最小。结论:调整医疗费用结构,缩短患者的住院天数,合理使用DRG支付方式,从而降低医疗费用、提高诊疗效率,实现总体控费目标。

针刺核心肌群联合康复训练治疗慢性非特异性腰痛的临床观察

【目的】观察针刺核心肌群联合康复训练治疗慢性非特异性腰痛的临床疗效。【方法】将96例慢性非特异性腰痛患者随机分为观察组和对照组,每组各48例,对照组给予康复训练,观察组在对照组治疗的基础上,给予针刺核心肌群训练。2组患者均连续治疗2周。治疗2周后,评价2组临床疗效,观察2组患者治疗前后腹横肌与多裂肌均方根(RMS)值的变化情况,以及Oswestry功能障碍指数评分、Roland-Morris功能障碍调查表评分、魁北克腰痛障碍量表评分的情况。比较2组患者治疗前后血清β-内啡肽、血清P物质、血清前列腺素E2水平的变化情况。治疗后随访5个月,评价2组患者的复发情况。【结果】(1)观察组总有效率为93.75%(45/48),对照组为81.25%(39/48)。观察组疗效优于对照组,差异有统计学意义(P<0.05)。(2)治疗后,2组患者的Oswestry功能障碍指数评分、Roland-Morris功能障碍调查表评分、魁北克腰痛障碍量表评分明显改善(P<0.05),且观察组在改善Oswestry功能障碍指数评分、Roland-Morris功能障碍调查表评分、魁北克腰痛障碍量表评分方面明显优于对照组,差异有统计学意义(P<0.05)。(3)治疗后,2组患者的腹横肌、多裂肌RMS值明显改善(P<0.05),且观察组在改善腹横肌、多裂肌RMS值方面明显优于对照组,差异有统计学意义(P<0.05)。(4)治疗后,2组患者β-内啡肽、P物质、前列腺素E2水平均明显改善(P<0.05),且观察组在改善β-内啡肽、P物质、前列腺素E2水平方面均明显优于对照组,差异均有统计学意义(P<0.05)。(5)治疗后观察组复发率为6.25%(3/48),对照组为20.83%(10/48),观察组复发率明显低于对照组,差异有统计学意义(P<0.05)。【结论】针刺核心肌群联合康复训练治疗慢性非特异性腰痛,能明显改善患者的临床症状,改善患者β-内啡肽、P物质、前列腺素E2水平,临床疗效显著。

新个人所得税改革对中低收入群体劳动供给的影响——基于中国家庭追踪调查的研究

如何通过科学的财税政策应对劳动年龄人口减少、推进共同富裕是学术界和政策界面临的共同命题,其中,收入所得税对激发劳动力市场活力、促进中低收入群体劳动参与的作用尤其引人注目。基于中国家庭追踪调查2016—2020年的三期面板数据,采取双重差分法分析2018年个人所得税改革对劳动供给的影响。实证结果表明:提高个税免征额促进了中低收入群体的劳动参与,但未显著增加劳动时间。经过更换回归模型、安慰剂检验等一系列稳健性检验后,研究结论依然成立。异质性分析显示,个税免征额提高对劳动供给的影响在不同性别和婚姻状况的群体中存在差异,对女性群体、已婚群体的劳动参与影响更大。机制上,新税改显著降低了个体由于照料家庭而退出劳动力市场的情况。因此,未来个税政策的改革方向应包括:持续关注重点人群的收入情况,有效发挥个税调节收入分配的功能;充分考虑个税改革对于女性和已婚群体劳动供给更强的激励作用,积极推行鼓励已婚女性就业的税收优惠政策;进一步细化专项附加扣除项目或标准,增强劳动者获得感,激励低收入群体就业,助力共同富裕。

An Analysis of Two-Dimensional Image Data Using a Grouping Estimator

Machine learning methods, one type of methods used in artificial intelligence, are now widely used to analyze two-dimensional (2D) images in various fields. In these analyses, estimating the boundary between two regions is basic but important. If the model contains stochastic factors such as random observation errors, determining the boundary is not easy. When the probability distributions are mis-specified, ordinal methods such as probit and logit maximum likelihood estimators (MLE) have large biases. The grouping estimator is a semiparametric estimator based on the grouping of data that does not require specific probability distributions. For 2D images, the grouping is simple. Monte Carlo experiments show that the grouping estimator clearly improves the probit MLE in many cases. The grouping estimator essentially makes the resolution density lower, and the present findings imply that methods using low-resolution image analyses might not be the proper ones in high-density image analyses. It is necessary to combine and compare the results of high- and low-resolution image analyses. The grouping estimator may provide theoretical justifications for such analysis.

混合气体抑制煤自燃的实验研究

为了研究混合气体(O_(2)/N_(2)和O_(2)/N_(2)/CO_(2))对煤自燃特性的影响,利用同步热分析仪、程序升温-气相色谱联用仪/红外光谱仪研究煤在混合气体下的特征温度、热效应/标志气体及官能团变化。结果表明:O_(2)/N_(2)气体氛围(简称气氛)下,随着N_(2)体积分数的增加,特征温度点滞后,TG、DTG、DSC均向高温偏移,放热量减少,燃烧阶段活化能升高,煤的最终耗氧量和CO体积分数均降低,煤中羟基增加,脂肪烃、含氧官能团、芳香烃的含量呈减少趋势;O_(2)/N_(2)/CO_(2)气氛下,随着CO_(2)体积分数的增加,特征温度点后移,放热量下降,燃烧阶段活化能减小,耗氧量、CO体积分数均降低,羟基、脂肪烃增加,含氧官能团的含量减少;当O_(2)体积分数相同时,O_(2)/N_(2)/CO_(2)混合气体中的失重率峰值、耗氧量与CO体积分数均小于O_(2)/N_(2)混合气体;-OH易被氧化发生脱水反应,煤在反应初期放热量较少,后期放热量快速增加,CO主要由-C=O生成。

失血性休克复苏液体的演进——低效价抗体O型全血正重新成为首选的应急通用桥接复苏液体

血液复苏是严重失血患者的关键急救措施。血液复苏液体的选用,经历了从全血到晶体液/胶体液、晶体液联合红细胞、等比例血液成分的演进过程。近20年来,采用低效价抗体O型全血(low titer group O whole blood,LTOWB)作为血液复苏的首选应急通用桥接复苏液,已发展成为大趋势。我们对全血在严重失血患者的应用历史和现状做一介绍,并提出我国采用LTOWB作为首选应急通用血液的进一步论证和验证研究建议。

最低工资水平对低收入群体和收入再分配的影响机制研究

党的二十届三中全会审议通过的《中共中央关于进一步全面深化改革、推进中国式现代化的决定》中明确提出,加强普惠性、基础性、兜底性民生建设,完善劳动者工资决定、合理增长、支付保障机制,多渠道增加居民财产性收入,有效增加低收入群体收入,稳步扩大中等收入群体规模,增强居民消费能力和意愿。而最低工资设计是否合理,将直接影响这一目标的科学实现。本文以2010-2018年CFPS家庭调查数据和各地区最低工资数据利用回归的方法验证最低工资调整与工资收入之间的关系,同时考察了最低工资的再分配效应。本文对于最低工资的研究利用微观调查数据对其政策效应进行检验,以验证最低工资对微观个体可能产生的影响,从历史数据的角度,对最低工资水平与低收入群体收入水平以及收入再分配的影响机制展开研究,这可以对现有的研究与政策制定提供参考。

基于非凸低秩张量分解和群稀疏总变分的高光谱混合噪声图像恢复

高光谱图像(Hyperspectral Image,HSI)在采集的过程中会被大量混合噪声污染,会影响遥感图像后续应用的性能,因此从混合噪声中恢复干净的HSI成为了重要的预处理过程。在本文中,提出了一种基于非凸低秩张量分解和群稀疏总变分正则化的高光谱混合噪声图像恢复模型;一方面,采用对数张量核范数来逼近HSI的低秩特性,可以利用高光谱数据固有的张量结构,同时减少对较大奇异值的收缩以保留图像更多细节特征;另一方面,采用群稀疏总变分正则化来增强HSI的空间稀疏性和相邻光谱间的相关性。并采用ADMM(Alternating Direction Multiplier Method)算法求解,实验证明该算法易于收敛。在模拟和真实的高光谱图像实验中,与其他方法相比,该方法在去除HSI混合噪声方面具有更好的性能。

急性脑梗死患者血清中高迁移率族蛋白、脂联素和氧化低密度脂蛋白的表达水平及其与颈动脉粥样硬化的相关性

目的探讨急性脑梗死患者颈动脉粥样硬化与血清中高迁移率族蛋白(HMGB)、脂联素和氧化低密度脂蛋白(oxLDL)表达水平的相关性。方法回顾性选取2021年9月至2023年9月唐山市人民医院收治的80例急性脑梗死患者作为急性脑梗死组,梗死类型:轻度梗死(梗死直径<3.0 cm)30例,中度梗死(梗死直径3.0~5.0 cm)30例,重度梗死(梗死直径>5.0 cm)20例;颈动脉粥样硬化:内膜粗糙28例,稳定斑块36例,不稳定斑块16例;选取80名无脑血管梗死的体检老年人作为对照组。检测两组研究对象血清中HMGB、脂联素和oxLDL的表达水平,并比较不同梗死类型、不同颈动脉粥样硬化急性脑梗死患者的血清中HMGB、脂联素和oxLDL表达水平,分析急性脑梗死患者颈动脉粥样硬化与血清中HMGB、脂联素和oxLDL表达水平的相关性。结果急性脑梗死组患者的血清中HMGB和oxLDL的表达水平分别为(25.47±5.15)ng/L、(5.22±1.04)mU/L,均明显高于对照组[(3.61±1.21)ng/L、(2.61±0.45)mU/L],脂联素的表达水平为(9.52±1.25)mg/L,明显低于对照组[(17.17±2.16)mg/L],差异均有统计学意义(P<0.05)。轻度梗死、中度梗死、重度梗死急性脑梗死患者的血清中HMGB和oxLDL的表达水平均逐渐升高,脂联素的表达水平逐渐降低,差异均有统计学意义(P<0.05)。内膜粗糙、稳定斑块、不稳定斑块急性脑梗死患者的血清中HMGB和oxLDL的表达水平均逐渐升高,脂联素的表达水平逐渐降低,差异均有统计学意义(P<0.05)。急性脑梗死患者颈动脉粥样硬化程度与血清中HMGB和oxLDL的表达水平均呈显著正相关(r=0.503、0.532,P<0.05),与脂联素表达水平呈显著负相关(r=-0.601,P<0.05)。结论急性脑梗死患者血清中HMGB和oxLDL的表达水平明显升高,脂联素的表达水平明显降低,血清HMGB、脂联素和oxLDL的表达水平与颈动脉粥样硬化病情显著相关,将有效依据提供给了临床诊治急性脑梗死。

共同富裕进程中低收入群体支出型返贫的发生机理与治理路径

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在线上购物配送环节中,综合考虑了碳排放成本、运输成本、货损成本、制冷成本、时间窗惩罚成本等多种成本因素,构建以总成本最小为目标的社区团购配送车辆路径优化模型。利用智能算法鲸鱼算法,对配送路径进行优化,验证了该算法的搜索能力和收敛性。