耦合生态系统服务供需的生态安全格局构建——以苏南地区为例

生态系统服务供需平衡是保障生态安全的基础,将生态系统服务供需作用流动机制融入生态安全格局构建对保障区域生态安全和提升人类生态福祉具有重要意义。基于景观生态学原理,提出耦合生态系统服务供需的生态安全格局构建逻辑方法,以苏南地区为研究区构建了景观生态安全格局和社会生态安全格局。研究结果表明:(1)耦合生态系统服务供需的生态安全格局应以维系区域生态安全和保障区域人类生态福祉为构建目标。其中,生态安全以生态系统服务与生态风险为核心关注对象,人类生态福祉的实现依赖于人类主动获取与生态系统服务流;(2)苏南地区生态系统服务供需间存在错配格局,在此基础上分别识别生态源地与需求源地4247.46km^(2)、1882.16km^(2),生态廊道与供需廊道1614.02km、1915.82km,生态夹点29处、生态障碍点23处、生态供需节点20处;(3)形成“三区四带两组团”的社会-景观生态安全格局优化布局方案,并在此基础上提出针对性保护修复策略,推动经济-生态空间协同发展。研究可为丰富区域生态安全格局构建理论和方法、推动国土空间优化与管控提供参考借鉴。

Molecular engineering binuclear copper catalysts for selective CO_(2) reduction to C_(2) products

Molecular copper catalysts serve as exemplary models for correlating the structure-reaction-mechanism relationship in the electrochemical CO_(2) reduction(eCO_(2)R),owing to their adaptable environments surrounding the copper metal centres.This investigation,employing density functional theory calculations,focuses on a novel family of binuclear Cu molecular catalysts.The modulation of their coordination configuration through the introduction of organic groups aims to assess their efficacy in converting CO_(2) to C_(2)products.Our findings highlight the crucial role of chemical valence state in shaping the characteristics of binuclear Cu catalysts,consequently influencing the eCO_(2)R behaviour,Notably,the Cu(Ⅱ)Cu(Ⅱ)macrocycle catalyst exhibits enhanced suppression of the hydrogen evolution reaction(HER),facilitating proton trans fer and the eCO_(2)R process.Fu rthermore,we explo re the impact of diverse electro n-withdrawing and electron-donating groups coordinated to the macrocycle(R=-F,-H,and-OCH_3)on the electron distribution in the molecular catalysts.Strategic placement of-OCH_3 groups in the macrocycles leads to a favourable oxidation state of the Cu centres and subsequent C-C coupling to form C_(2) products.This research provides fundamental insights into the design and optimization of binuclear Cu molecular catalysts for the electrochemical conversion of CO_(2) to value-added C_(2) products.

Benchmark experiment on slab^(238)U with D-T neutrons for validation of evaluated nuclear data

A benchmark experiment on^(238)U slab samples was conducted using a deuterium-tritium neutron source at the China Institute of Atomic Energy.The leakage neutron spectra within energy levels of 0.8-16 MeV at 60°and 120°were measured using the time-of-flight method.The samples were prepared as rectangular slabs with a 30 cm square base and thicknesses of 3,6,and 9 cm.The leakage neutron spectra were also calculated using the MCNP-4C program based on the latest evaluated files of^(238)U evaluated neutron data from CENDL-3.2,ENDF/B-Ⅷ.0,JENDL-5.0,and JEFF-3.3.Based on the comparison,the deficiencies and improvements in^(238)U evaluated nuclear data were analyzed.The results showed the following.(1)The calculated results for CENDL-3.2 significantly overestimated the measurements in the energy interval of elastic scattering at 60°and 120°.(2)The calculated results of CENDL-3.2 overestimated the measurements in the energy interval of inelastic scattering at 120°.(3)The calculated results for CENDL-3.2 significantly overestimated the measurements in the 3-8.5 MeV energy interval at 60°and 120°.(4)The calculated results with JENDL-5.0 were generally consistent with the measurement results.

Qualitative analysis of aromatic compounds via 1D TOCSY techniques

The aromatic compounds,including o-xylene,m-xylene,p-xylene,and ethylbenzene,primarily originate from the catalytic reforming of crude oil,and have a wide variety of applications.However,because of similar physical and chemical properties,these compounds are difficult to be identified by gas chromatography(GC)without standard samples.With the development of modern nuclear magnetic resonance(NMR)techniques,NMR has emerged as a powerful and efficient tool for the rapid analysis of complex and crude mixtures without purification.In this study,the parameters of one-dimensional(1D)total correlation spectroscopy(TOCSY)NMR techniques,including 1D selective gradient TOCSY and 1D chemicalshift-selective filtration(CSSF)with TOCSY,were optimized to obtain comprehensive molecular structure information.The results indicate that the overlapped signals in NMR spectra of nonpolar aromatic compounds(including o-xylene,m-xylene,p-xylene and ethylbenzene),polar aromatic compounds(benzyl alcohol,benzaldehyde,benzoic acid),and aromatic compounds with additional conjugated bonds(styrene)can be resolved in 1D TOCSY.More importantly,full molecular structures can be clearly distinguished by setting appropriate mixing time in 1D TOCSY.This approach simplifies the NMR spectra,provides structural information of entire molecules,and can be applied for the analysis of other structural isomers.

The flavonoids from Pentorum chinense Pursh.mediates ferroptosis to alleviate sorafenib-induced liver injury in BRL-3A cells

Background:Drug-induced liver damage is a severe medical issue that affects people all over the world.Sorafenib has some side effects that cause liver injury.A dietary medicinal plant called Penthorum chinense Pursh.(PCP)has hepatoprotective properties.There are currently few reports on PCP’s protective impact and mechanism against sorafenib-induced liver injury.Methods:To create a liver injury model,sorafenib was administered to BRL-3A cells.Cell viability assays,immunofluorescence tests,Western blotting,real-time quantitative PCR,and high-content imaging systems were utilized to examine PCP’s effect and mechanism.Results:In this study,PCP treatment mitigated the liver damage caused by sorafenib by enhancing cell survival,lowering lipid reactive oxygen species and malondialdehyde levels,and elevating glutathione levels.In addition,PCP can enhance the protein expression of cystine/glutamate transporter xCT and glutathione peroxidase 4,reduce iron content and alleviate mitochondrial toxicity.Further mechanism studies revealed that PCP inhibited ferroptosis by promoting the production of nuclear factor E2-related factor 2 nuclear translocation and subsequently affecting target genes(HO-1 and NQO1).Conclusion:Together,PCP regulates the nuclear factor E2-related factor 2 pathway,which helps to lessen ferroptosis brought on by sorafenib.

Clinical experience sharing on gastric microneuroendocrine tumors: A case report

BACKGROUND The majority of gastric neuroendocrine tumors(G-NENs)are present in various lesions under endoscopy,and they can be polypoid uplifts,submucosal tumors or papules,erosions,and ulcers.The lesions are mostly confined to the mucosal or submucosal layer,usually less than 2 cm,and exclusively localized to the gastric body or fundus.In type 1 G-NENs,about 22%of cases have no visible lesions under an endoscope,and such lesions can only be detected via biopsies(microcar-cinoids).CONCLUSION In the case under study,the patient did not have any visible raised lesions under a gastroscope,and the lesions were found only after a random biopsy.This article combines the endoscopic manifestations and clinical features of the lesions in this case to improve the diagnosis of G-NENs.

1990-2021年环塔里木盆地植被覆盖度(FVC)时空数据集

塔里木盆地是生态极端脆弱区,更是人为扰动剧烈区,荒漠化问题尤为突出。植被覆盖度能够很好地反映地表植被的繁茂程度,是荒漠化监测的一个重要指标。开展区域植被覆盖度监测是掌握荒漠化动态变化,全面分析荒漠化成因等方面研究的基础。研究基于GEE遥感云平台,以1990–2021年LANDSAT卫星植被生长季(4–10月)影像为数据源,获取了环塔里木盆地1990–2021年间7期植被覆盖度数据集。研究通过采用0.5%置信度截取NDVI的上下阈值,获得纯植被覆盖像元和纯土壤覆盖像元的NDVI值,来消除年际间气候差异对植被覆盖度计算的影响,保证各年度植被覆盖度计算的一致性。数据集使用109块无人机正射样地,经过预处理及植被指数法加大津算法得到的FVC值作为验证样本。数据集精度为R^(2)=0.79、线性表达式为y=0.8126x-0.0267。本数据集可为荒漠化变化、驱动机制等方面的研究提供数据支撑。

基于16S rDNA测序的巢湖流域水体粪便污染溯源

排入地表水中的动物粪便会带来一系列生态与公共卫生问题,快速准确鉴别污染来源对于源头控制与污染治理具有重要意义。基于细菌群落的微生物溯源技术(Community-based microbial source tracking)以及高通量DNA测序技术(Nextgeneration sequencing,NGS),对污染源中微生物和环境样本中的微生物群落进行比较分析,进而对水体中粪便污染来源进行预测。本文利用16S rDNA测序,系统分析与比较了巢湖流域水体、沉积物样本与广泛的潜在污染源(包括村庄与养猪场污水,野生水鸟粪便,人类与家禽、家畜粪便)的细菌群落组成,同时,利用基于机器学习的溯源软件FEAST与Sourcetracker,对水体、沉积物样本的潜在污染源进行了预测。结果表明:水体与沉积物样本的微生物多样性显著高于粪便样本,其中巢湖水体与河流沉积物样本具有最高的物种多样性,同时样本中也存在大量未分类物种。变形菌门(Proteobacteria)、放线菌门(Actinobacteria),拟杆菌门(Bacteroidetes)广泛分布于所有样本中。溯源分析结果表明,村庄排污口与污水处理厂排污口样本是河水样本最主要的污染来源,沉积物与湖水样本则预测存在猪场排污水与野生水鸟粪便的污染,所有样本未检测到来自人粪与鸡粪的污染。

全域土地综合整治助力乡村空心化治理的作用机制探析:基于乡村功能演化视角

研究目的:从乡村功能演化视角,探索全域整治助力乡村空心化治理机制,以期为空心化治理决策提供参考。研究方法:理论解析法、半结构式访谈法。研究结果:(1)乡村功能演化是生产功能主导向多功能协调的转型过程,具有城镇去中心化、空间减量化、数字智慧化、绿色生态化等特征;(2)全域整治具有对象全面、目标多元、手段复合、主体多样、机制灵活等优势,更适合解决日益复杂的空心化问题;(3)全域整治协同利益主体,以多元机制支持项目建设,实现用地结构重构、质量重塑、布局重组,促进产业升级、融合与增值,结合设施完善和生态改善,实现“地—业—钱—人”空心化治理和三生功能提升;(4)实证研究表明,全域整治以土地资源的优化配置,促进了产业升级与融合,推动了多渠道资金投入和产出,吸引了人口回流,实现了多维空心化治理。研究结论:从乡村功能演化视角明确了全域整治助力乡村空心化治理机制,未来应从理论内涵、治理路径、政策优化等层面深化研究。

综合“同质等效—流补平衡”的耕地“进出平衡”管制:方法与实证

研究目的:明确耕地“进出平衡”的管制体系,构建综合“同质等效—流补平衡”的管制框架,为科学制定农用地用途管制规则、合理确定耕地“进出平衡”管制要求提供参考。研究方法:逻辑推理法和案例分析法。研究结果:(1)耕地“进出平衡”应以一般耕地和可恢复非耕农用地为对象,综合“同质等效”与“流补平衡”的管制要求,实现耕地长期稳定利用的目标;(2)以“同质等效”和“流补平衡”为管制评价依据和分区划定原则,可为落实区域耕地“进出平衡”提供方法支撑;(3)宜兴市永久基本农田外的农用地可划分为备选补入区(2848.07 hm^(2))、备选流出区(2847.70 hm^(2))、重点保护区(3063.06 hm^(2))和特色发展区(16286.94 hm^(2))4种类型,落实耕地“进出平衡”管制后宜兴市耕地耕作适宜性均值可由0.60提升至0.64。研究结论:明确耕地“进出平衡”管制规则有助于落实耕地保有量和明确耕地利用优先序,并且实现耕地的量质并提、格局优化和功效改善。

乌兰布和沙漠东北缘生态承载力时空动态分析

生态承载力是衡量生态系统稳定性的重要指标之一,其时空变化分析有助于了解地区生态环境变化趋势,对生态环境的治理与恢复评价、环境整体的可持续发展研究以及国土资源优化也具有全面的参考价值。以乌兰布和沙漠东北缘的干旱半干旱地区为研究区,以Landsat系列遥感数据为数据源,基于地区的实际生态状况,构建生态承载力综合指标评价体系,进而获得地区生态承载力时空分布及演变格局,并从降雨、温度以及土地利用变化的角度对生态承载力的变化进行驱动分析。结果表明,1990—2020年乌兰布和沙漠东北缘区域的生态承载力整体呈现先减少后增加的趋势,其中黄河以北的灌区向西南方向的荒漠化区域不断扩张,较高生态承载力的面积占比大幅度增加,高生态承载力面积降低,受土地开发利用的影响较大,其次是温度和降雨,而黄河以南的荒漠化区域以中生态承载力为主,在2010年之前大面积转为较低生态承载力,到2020年又恢复到中生态承载力,受温度影响较大,其次是降雨和灌草植被覆盖状况的变化。

Electrochromic-Induced Rechargeable Aqueous Batteries: An Integrated Multifunctional System for Cross-Domain Applications

Multifunctional electrochromic-induced rechargeable aqueous batteries(MERABs) integrate electrochromism and aqueous ion batteries into one platform, which is able to deliver the conversion and storage of photo-thermal-electrochemical sources.Aqueous ion batteries compensate for the drawbacks of slow kinetic reactions and unsatisfied storage capacities of electrochromic devices. On the other hand, electrochromic technology can enable dynamically regulation of solar light and heat radiation. However,MERABs still face several technical issues, including a trade-off between electrochromic and electrochemical performance, low conversion efficiency and poor service life. In this connection, novel device configuration and electrode materials, and an optimized compatibility need to be considered for multidisciplinary applications. In this review,the unique advantages, key challenges and advanced applications are elucidated in a timely and comprehensive manner. Firstly, the prerequisites for effective integration of the working mechanism and device configuration, as well as the choice of electrode materials are examined. Secondly, the latest advances in the applications of MERABs are discussed, including wearable, self-powered, integrated systems and multisystem conversion. Finally, perspectives on the current challenges and future development are outlined, highlighting the giant leap required from laboratory prototypes to large-scale production and eventual commercialization.

The role of copper in enhancing the performance of heteronuclear diatomic catalysts for the electrochemical CO_(2)conversion to C_(1) chemicals

Diatomic catalysts(DACs)with two adjacent metal atoms supported on graphene can offer diverse functionalities,overcoming the inherent limitations of single atom catalysts(SACs).In this study,density functional theory calculations were conducted to investigate the reactivity of the carbon dioxide(CO_(2))reduction reaction(CO_(2)RR)on metal sites of both DACs and SACs,as well as their synergistic effects on activity and selectivity.Calculation of the Gibbs free energies of CO_(2)RR and associated values of the limiting potentials to generate C_(1) products showed that Cu acts as a promoter rather than an active catalytic centre in the catalytic CO_(2)conversion on heteronuclear DACs(CuN_(4)-MN_(4)),improving the catalytic activity on the other metal compared to the related SAC MN_(4).Cu enhances the initial reduction of CO_(2)by promoting orbital hybridization between the key intermediate*COOH 2p-orbitals and the metals 3d-orbitals around the Fermi level.This degree of hybridization in the DACs CuN_(4)-MN_(4) decreases from Fe to Co,Ni,and Zn.Our work demonstrates how Cu regulates the CO_(2)RR performance of heteronuclear DACs,offering an effective approach to designing practical,stable,and high-performing diatomic catalysts for CO_(2)electroreduction.

不同珊瑚对酸化、苯并[a]芘单一和复合胁迫的生理响应

海洋酸化和持久性有机污染物的排放对珊瑚礁生态系统的健康具有负面影响。为阐明酸化、苯并[a]芘(benzo[a]pyrene,BaP)单一及复合胁迫对2种不同形态珊瑚共生虫黄藻光合生理指标和抗氧化酶活性的影响,本研究以澄黄滨珊瑚(Porites lutea)和多孔鹿角珊瑚(Acropora milllepora)为研究对象,分析了不同胁迫处理(酸化、BaP胁迫、酸化与BaP复合胁迫)对2种珊瑚的共生虫黄藻密度、叶绿素a含量以及抗氧化酶活性的毒性效应。研究结果显示,单一酸化胁迫(pH=7.8)下,多孔鹿角珊瑚共生虫黄藻密度、叶绿素a含量和超氧化物歧化酶(SOD)酶活性呈显著下降(P<0.01),过氧化物酶(POD)酶活性显著上升(P<0.01);澄黄滨珊瑚共生虫黄藻密度、叶绿素a含量无显著变化,SOD、POD酶活性显著下降(P<0.01)。单一BaP(10μg·L^(-1))胁迫下,多孔鹿角珊瑚共生虫黄藻的密度、叶绿素a含量显著下降(P<0.01),SOD、POD酶活性无显著变化;澄黄滨珊瑚共生虫黄藻密度无显著变化,叶绿素a含量显著下降(P<0.01),SOD、POD酶活性明显升高(P<0.01);在海水酸化复合BaP胁迫下,多孔鹿角珊瑚的共生虫黄藻叶绿素a含量、SOD酶活性显著下降(P<0.01),澄黄滨珊瑚共生虫黄藻密度显著升高(P<0.05),POD酶活性显著下降(P<0.01)。研究结果表明,珊瑚对不同环境的胁迫响应存在种间差异,多孔鹿角珊瑚较澄黄滨珊瑚更加敏感;珊瑚共生虫黄藻叶绿素a含量变化更适合作为海洋酸化、BaP胁迫的指示因子。

Combined imbibition system with black nanosheet and low-salinity water for improving oil recovery in tight sandstone reservoirs

Nanomaterials and low-salinity water(LSW)are two popular enhanced oil recovery(EOR)methods that have been widely studied in recent years.The former is used for in-depth conformance improvement and the latter for microscopic oil displacement(by altering the potential and contact angle).However,there are few literature on combining them to achieve synergistic effects,especially for tight sandstone res-ervoirs.Based on the reservoir conditions of the Jimusar Oilfield,this study investigated the oil recovery mechanism of the combined imbibition system,which was composed of black nanosheet(BN)and LSW.Its performances including decreasing interfacial tension,emulsification,and wettability alterations were evaluated.The imbibition differences between the single system of BN and LSW and the combined BN-LsW imbibition system were then compared.Results showed that the combined imbibition system had a better emulsification effect on the crude oil and could also alter the wettability of the core surface.Moreover,the combined system could increase both the imbibition rate and the ultimate oil recovery.The nuclear magnetic T2 spectrum also indicated that the addition of black nanosheets could divert more fluid into small pores and thus improve the microscopic sweep efficiency.

Effect of nano TiO_(2) and SiO_(2) on gelation performance of HPAM/PEI gels for high-temperature reservoir conformance improvement

Nanoparticles have been widely used in polymer gel systems in recent years to improve gelation performance under high-temperature reservoir conditions. However, different types of nanoparticles have different effects on their gelation performance, which has been little researched. In this study, the high-temperature gelation performance, chemical structure, and microstructure of polymer gels prepared from two nanomaterials (i.e., nano-SiO_(2) and nano-TiO_(2)) were measured. The conventional HPAM/PEI polymer gel system was employed as the control sample. Results showed that the addition of nano-TiO_(2) could significantly enhance the gel strength of HPAM/PEI gel at 80 ℃. The gel strength of the enhanced HPAM/PEI gel with 0.1 wt% nano-TiO_(2) could reach grade I. The system also had excellent high-temperature stability at 150 ℃. The enhanced HPAM/PEI gel with 0.02 wt% nano-TiO_(2) reached the maximum gel strength at 150 ℃ with a storage modulus (G′) of 15 Pa, which can meet the need for efficient plugging. However, the nano-SiO_(2) enhanced HPAM/PEI polymer gel system showed weaker gel strength than that with nano-TiO_(2) at both 80 and 150 ℃ with G′ lower than 5 Pa. Microstructures showed that the nano-TiO_(2) enhanced HPAM/PEI gel had denser three-dimensional (3D) mesh structures, which makes the nano-TiO_(2) enhanced HPAM/PEI gel more firmly bound to water. The FT-IR results also confirmed that the chemical structure of the nano-TiO_(2) enhanced HPAM/PEI gel was more thermally stable than nano-SiO_(2) since there was a large amount of –OH groups on the structure surface. Therefore, nano-TiO_(2) was more suitable as the reinforcing material for HPAM/PEI gels for high-temperature petroleum reservoir conformance improvement.

Measurement and simulation of the leakage neutron spectra from Fe spheres bombarded with 14 MeV neutrons

Iron is commonly used as a structural and shielding material in nuclear devices. The accuracy of its nuclear data is critical for the design of nuclear devices. The evaluation data of ^(56)Fe isotopes in the latest version of the CENDL-3.2 library from China was significantly updated. This new data must be tested before it can be used. To test the reliability of this data and assess the shielding effect, a shielding benchmark experiment was conducted with natural Fe spherical samples using a pulsed deuterium–tritium neutron source at the China Institute of Atomic Energy(CIAE). The leakage neutron spectra from the natural spherical iron samples with different thicknesses(4.5, 7.5, and 12 cm) were measured between 0.8 and 16 MeV after interacting with 14 MeV neutrons using the time-of-flight method. The simulation results were obtained by Monte Carlo simulations by employing the Fe data from the CENDL-3.2, ENDF/B-VIII.0, and JEDNL-5.0 libraries. The measured and simulated leakage neutron spectra and penetration rates were compared, demonstrating that the CENDL-3.2 library performs sufficiently overall. The simulation results of the other two libraries were underestimated for scattering at the continuum energy level.

NMR diffusion analysis of catalytic conversion mixtures from lignocellulose biomass using PSYCHE-iDOSY

The component analysis and structure characterization of complex mixtures of biomass conversion remain a challenging work.Hence,developing effective and easy to use techniques is necessary.Diffusion-ordered NMR spectroscopy(DOSY)is a non-selective and non-invasive method capable of achieving pseudo-separation and structure assignments of individual compounds from biomass mixtures by providing diffusion coefficients(D)of the components.However,the conventional 1H DOSY NMR is limited by crowded resonances when analyzing complex mixtures containing similar chemical structure resulting in similar coefficient.Herein we describe the application of an advanced diffusion NMR method,Pure Shift Yielded by CHirp Excitation DOSY(PSYCHE-iDOSY),which can record high-resolution signal diffusion spectra efficiently separating compounds in model and genuine mixture samples from cellulose,hemicellulose and lignin.Complicated sets of isomers(D-glucose/D-fructose/D-mannose and 1,2-/1,5-pentadiol),homologous compounds(ethylene glycol and 1,2-propylene glycol),model compounds of lignin,and a genuine reaction system(furfuryl alcohol hydrogenolysis with ring opening)were successfully separated in the diffusion dimension.The results show that the ultrahigh-resolution DOSY technique is capable of detecting and pseudo-separating the mixture components of C_(5)/C_(6) sugar conversion products and its derivative hydrogenation/hydrogenolysis from lignocellulose biomass.

血清学血小板/白蛋白、C反应蛋白/白蛋白评估克罗恩病黏膜愈合及疾病复发的价值

背景目前对克罗恩病(Crohn’s disease,CD)血清学标志物的研究较多的炎症性标志物主要为C反应蛋白,但无法用单独指标进行预测,近年来有研究发现血清标志物的联合应用可更准确的进行预测,且血清血小板/白蛋白(platelet/serum albumin,PLT/ALB)、C反应蛋白/白蛋白(C-reactive protein/serum albumin,CRP/ALB)值在评估炎症活动期等方面的特异性较高.目的探讨血清学血小板/白蛋白、C反应蛋白/白蛋白评估CD黏膜愈合及疾病复发的价值.方法选取新洲区人民医院2019-04/2021-04收治的85例CD患者.根据临床及内镜下愈合标准分为黏膜愈合组(n=44)和黏膜未愈合组(n=41),比较两组患者一般资料、治疗前及治疗6 mo后血清ALB、PLT、CRP、PLT/ALB、CRP/ALB水平及与SES-CD评分的相关性分析及评估黏膜愈合的价值,根据是否复发分为复发组和未复发组,比较两组血清指标水平及血清指标预测疾病复发的价值.结果2019-04/2021-04收治的85例CD患者经过6 mo治疗后,黏膜愈合组(n=44)中ALB水平较黏膜未愈合组(n=41)显著升高,而PLT、CRP水平显著降低,且PLT/ALB、CRP/ALB指标水平均降低,差异均具有统计学意义(P<0.05),血清ALB、PLT、CRP、PLT/ALB、CRP/ALB指标与SES-CD评分有明显相关性;采用受试者工作特征曲线(receiver operating characteristic curve,ROC)评估,ALB、PLT、CRP、CRP/ALB及PLT/ALB评估黏膜愈合的ROC曲线与坐标轴形成面积(area under ROC curve,AUC)值分别为0.712、0.662、0.774、0.776、0.719(AUC>0.5);治疗6 mo后,复发组(n=45)ALB较未复发组(n=40)明显降低,而PLT、CRP、PLT/ALB、CRP/ALB水平升高,差异具有统计学意义(P<0.05);采用ROC曲线评估,ALB、PLT、CRP、CRP/ALB和PLT/ALB评估疾病复发的AUC值为0.641、0.628、0.643、0.652、0.651(AUC>0.5).结论血清学优化PLT/ALB、CRP/ALB指标在评估CD黏膜愈合及疾病复发的效果更佳,其临床价值高.

基于广义谐振理论的输电线路无源干扰谐振频率求解

IEEE标准难以完全预测中波频段输电线路的无源干扰谐振频率,同时现有方法计算量过大,为解决此问题,提出基于广义谐振理论的输电线路无源干扰谐振频率求解方法。首先,结合坡印廷定理,从电磁能量平衡的角度出发,将包含输电线路及无线电台站的封闭面等效为广义封闭系统;然后,根据复频率理论,推导输电线路与无线电台站所构成电磁系统的谐振频率与品质因数Q值之间的关系表达式;最后,对观测点的散射场强进行采样,采用模型参数估计的方法求解反映散射场强与频率映射关系的系统函数。以IEEE计算输电线路无源干扰的模型为算例,通过仿真计算验证所提方法可将无源干扰谐振频率预测范围扩展至3 MHz。此外,与矩量法相比,当采样点选择适当时,最大谐振频率偏差可控制在3%以内。