能谱CT多参数成像评估胆结石成分的应用价值

目的探究能谱CT多参数成像评估胆固醇结石和非胆固醇结石的应用价值。方法收集125枚胆结石置入猪肝模型中行CT能谱模式扫描,并重建普通螺旋CT图像,测量所有胆结石单能量40 keV、100 keV时的CT值(HU40 keV、HU100 keV)、有效原子序数(Eff-Z)和普通螺旋CT值(HU120 kVp like),并计算40~100 keV区间能谱衰减斜率(K),根据红外光谱分析结果分为胆固醇结石组56枚和非胆固醇结石组69枚。采用秩和检验比较两组各参数差异,利用多因素Logistic回归分析判断胆结石成分的独立影响参数,绘制受试者工作特征(ROC)曲线,分析评估影响效能及截断值。招募胆结石患者80例,术前行CT能谱模式扫描并重建普通螺旋CT图像,分别预测术前胆结石成分,术后取出86枚胆结石行红外光谱分析,分析各参数预测结果的准确性。结果体外非胆固醇结石组HU40 keV、HU100 keV、Eff-Z、K值及HU120 kVp like与胆固醇结石组比较,差异有统计学意义(P <0.05),非胆固醇结石组高于胆固醇结石组。多因素Logistic回归分析结果显示仅Eff-Z [OR=12.57(95%CI:5.38,29.35)]是胆固醇和非胆固醇结石的影响因素,其ROC曲线下面积为0.962(95%CI:0.928,0.997),对应截断值为7.27。体内验证结果显示,以术后红外光谱分析为参照,能谱CT预测胆结石成分的总准确率为91.86%(95%CI:0.831,0.967),而普通螺旋CT预测的总准确率仅为77.9%(95%CI:0.690,0.872),能谱CT与红外光谱分析结果具有较高的一致性(κ=0.832,P <0.05)。而普通螺旋CT值预测胆结石成分结果与红外光谱分析结果一致性一般(κ=0.561,P <0.05)。结论能谱CT多参数成像可较准确地评估胆结石成分,尤其以Eff-Z参考价值为佳,优于普通螺旋CT扫描。

Field Size Evaluation with a High Resolution 2D Diode Array for Variable-Aperture Collimators Used in Robotic Radiosurgery

Robotic radiosurgery/Radiotherapy is increasingly adopted in clinics, and quality assurance (QA) of CyberKnife’s variable-aperture IrisTM collimators requires sub-millimeter precision. Conventional film-based QA for the 12 IrisTM cone sizes (ranging from 5 to 60 mm) is both time consuming (120 minutes for all or 30 minutes for 3 cone sizes) and highly experience dependent. To improve the efficiency, a high-resolution 2D diode detector array, sampling every 2.5 mm, was evaluated for IrisTM aperture size QA. This study focused on a spatial frequency analysis, a dose profile reconstruction, and a sensitivity study to beam size variances. Dose profiles of the 12 cones scanned with a high-resolution diode in a water tank were utilized as the gold standard for comparison. Spatial Fourier transform of these profiles were analyzed to explore applicable sampling frequency. Next, the dose profiles were artificially sampled with a 2.5 mm gap, and then interpolated using a Python-based cubic B-spline. Finally, sensitivity of the diode array system to various field sizes was measured by changing source to detector distance. We found, utilizing the diodes system, QA time was reduced to less than 10 minutes. Spatial frequency of the dose profile showed little contribution beyond 0.2 mm-1, so a Nyquist sampling of 0.4 mm-1 is appropriate for dose verification, corresponding to a 2.5 mm gap. Dose profiles were reconstructed using Cubic B-spline with good agreements to nominal for cones 7.5 mm and larger. The measured IrisTM size using the SRS MapCheck had a standard error of ±0.12 mm. Primarily, the 2D Diode array with a spatial resolution 0.4 mm-1 is appropriate for dose verification for these cones above 7.5 mm, and its application would substantially improve IrisTM QA efficiency.

惯容式油气悬架力学建模和试验研究

为满足轮式装甲车辆对高机动越野性能的要求,提出了将滚珠丝杠惯容器与双筒式油气弹簧集成的技术方案,构建了惯容式油气悬架装置。通过剖析该悬架装置弹性力、阻尼力和惯性力的产生机理,揭示了各参数之间的耦合关系,提取出3个相互独立的关键结构参数,采用正交试验法,结合惯容式悬架系统非线性动力学仿真,确定了上述3个关键结构参数的最优值。力学特性试验和1/4悬架试验的结果表明,与传统油气悬架相比,采用惯容式悬架使车体振动加速度降低了13.89%,大幅提高了车辆的乘坐舒适性。

腹腔镜手术对子宫内膜异位症合并不孕症患者的妊娠结局及影响因素分析

目的分析腹腔镜手术治疗对子宫内膜异位症(EMT)合并不孕症妊娠情况的影响,并探讨影响妊娠结局的因素。方法选取青海省妇女儿童医院子宫内膜异位症合并不孕症患者120 例作为研究对象,随机分为观察组与对照组,每组60 例。观察组实施腹腔镜手术治疗;对照组实施常规开腹手术治疗。分析两组手术情况及2 年内的妊娠结局,单因素及Logistic 多因素分析妊娠率影响因素。结果与对照组比较,观察组术中出血量、手术时间和术后住院时间均减少(P <0.05)。随访2 年,两组妊娠率、妊娠结局及子宫内膜异位症复发率比较,差异无统计学意义(P >0.05)。单因素及多因素Logistic 分析术后体外受精-胚胎移植(IVF-ET)是妊娠不良结局的主要影响因素(P <0.05)。结论腹腔镜治疗子宫内膜异位症合并不孕症对患者机体损伤较小,治疗后影响患者妊娠的主要因素为接受IVF-ET 治疗,追溯影响妊娠结局的原因较多而不确定,因此需要大规模、深入的样本研究,进一步分析子宫内膜异位症合并不孕症患者治疗后妊娠的影响因素,从而完善治疗策略。

Effects of Bacillus coagulans supplementation on the growth performance and gut health of broiler chickens with Clostridium perfringens-induced necrotic enteritis

Background: The poultry industry is in need of effective antibiotic alternatives to control outbreaks of necrotic enteritis(NE) due to Clostridium perfringens.Methods: This study was conducted to investigate the effects of feeding Bacil us coagulans on the growth performance and gut health of broiler chickens with C. perfringens-induced NE. Two hundred and forty 1-day-old broiler chicks were randomly assigned to a 2 × 2 factorial arrangement with two dietary B. coagulans levels(0 or 4 × 109 CFU/kg of diet) and two disease chal enge statuses(control or NE chal enged).Results: NE-induced reduction in body weight gain was relieved by the addition of B. coagulans into broiler diets compared with the NE-infected birds. NE infection damaged intestinal morphological structure, promoted intestinal C.perfringens growth and liver invasion, and enhanced anti-C. perfringens specific sI gA concentrations in the gut and specific IgG levels in serum compared with the uninfected birds. NE infection significantly(P < 0.05) decreased mucin-2(at 14 d post-infection(DPI), tol-like receptor 2(TLR2, at 7 and 14 DPI), TLR4(at 7 and 14 DPI), tumor necrosis factor super family15(TNFSF15, at 7 and 14 DPI), lysozyme(LYZ, at 14 DPI) and fowlicidin-2(at 7 and 14 DPI) mR NA levels, whereas it dramatical y(P = 0.001) increased IFN-γ mR NA levels at 7 DPI. However, chal enged birds fed diets supplemented with B.coagulans showed a significant(P < 0.01) decrease in gut lesion scores, decreased C. perfringens numbers in the cecum and liver, and an increase in fowlicidin-2 mR NA levels in compared with the uninfected birds. In addition, compared with the non-supplemented group, dietary inclusion of B. coagulans improved intestinal barrier structure, further increased specific sI gA levels and alkaline phosphatase(IAP) activity in the jejunum, enhanced the expression of jejunum lysozyme mR NA, and inhibited the growth, colonization, and invasion of C. perfringens; in contrast, it reduced serum-specific IgG concentrations and jejunum IFN-γ mR NA levels.Conclusion: These results indicated that dietary B. coagulans supplementation appeared to be effective in preventing the occurrence and reducing the severity of C. perfringens-induced NE in broiler chickens.

能力、关系与晋升速度:基于522名县委书记的实证研究

当下对于官员晋升的研究大多聚焦于官员是否获得晋升机会及其晋升概率问题,较少关注官员的晋升速度。论文基于全国522名县级行政区党委书记的个人信息数据,分析了他们的群体特征,并通过建立多元线性回归模型,研究能力和关系对县域干部晋升速度的影响。研究结果表明:县域干部的晋升速度不仅遵循能力逻辑,(全日制)学历高、具有非技术性学科背景、基层工作经历短的干部晋升速度更快;同时也遵循关系逻辑,秘书任职经历加快基层干部向县委书记一职的晋升速度;但相比之下,能力逻辑的效应大于关系逻辑。据此认为,破除“唯学历”偏向,从严规范破格提拔,建立崇尚实干的考核制度和激励体系,匡正选人用人的风气是未来地方干部人事制度改革的重点。

Ascorbic acid synthesis and transportation capacity in old laying hens and the effects of dietary supplementation with ascorbic acid

Background: Laying hens over 75 weeks of age commonly show great declines in immunity and production performance.It is unclear whether these declines can be relieved by supplementing with ascorbic acid(AA) in feed.Two trials were conducted to investigate the synthesis and metabolism of AA in layers of different ages and the effects of dietary supplemental AA on the performance and the immune and antioxidant statuses of 78 weeks old hens.Methods: In Exp.1,equal numbers(24 hens) of 35 weeks old(Young) and 75 weeks old(Old) layers were fed the same diet without AA supplementation for 4 weeks.In Exp.2,360 healthy 78 weeks old laying hens were randomly assigned to 4 treatments(basal diet supplemented with 0,0.25,0.5,or 1 g AA/kg diet) in an 8-week feeding trial.Results: The old hens tended to have decreased L-gulonolactone oxidase(GLO) synthase activity in the kidney and liver than that of the young hens(P = 0.07 and P = 0.05,respectively).Compared with the young hens,the old hens had lower hepatic antioxidant capacity allowing for the lower thioredoxin(TXN),thioredoxin reductase(TXNR) and cytochrome b5 reductase(CYB5 R) gene expression(P < 0.05),whereas increased sodium-dependent vitamin C transporter(SVCT) 1 expression levels in the ileum and kidney and enhanced splenic and hepatic AA concentrations(P < 0.05).Dietary supplementation with AA significantly decreased GLO enzyme activity but increased splenic AA concentration and anti-bovine serum albumin IgG levels(P < 0.05) and tended to increase CD4+T lymphocyte numbers(P = 0.06) in serum.Supplementation of 0.25 g AA/kg diet significantly increased hepatic total antioxidant capacity(T-AOC,P < 0.05) relative to the control group.Conclusions: Laying hens could synthesize AA in both the kidney and the liver,though the GLO enzyme activities were 100 times greater in kidneys than in livers.The old laying hens had greater absorption and reabsorption capacity and higher AA retention in some tissues that did the young hens.Dietary supplementation of AA can improve the health of old layers by enhancing immunity and antioxidant capacity.

Effect of dietary nonphytate phosphorus on laying performance and small intestinal epithelial phosphate transporter expression in Dwarf pink-shell laying hens

This study examined the effects of various levels of dietary nonphytate phosphorus on laying performance and the expression patterns of phosphorus metabolism related genes in Dwarf pink-shell Jaying hens. A total of 405 28-week-old Dwarf pink-shell laying hens were fed the same corn-soybean basal meals but containing 0.20%, 0.25%, 0.30%, 0.35% or 0.40% nonphytate phosphorus. The results showed that feed intake, egg production, and average egg weights were quadratically correlated with dietary nonphytate phosphorus content （P 〈 0.05）, and the highest egg production, feed intake and average egg weights were achieved when dietary nonphytate phosphorus was at 0.3% （P 〈 0.05）. mRNA expression of intestinal sodium phosphorus co-transporter linearly decreased when dietary nonphytate phosphorus increased, mRNA and protein expression of intestinal calbindin and vitamin D receptor correlated quadratically with dietary nonphytate phosphorus, and the highest expression was found when dietary available phosphorus was at 0.2,5% to 0.3%. In conclusion, the ideal phosphorus requirement for Dwarf pink-shell layer hens is estimated to be 0.3% in a corn-soybean diet. With this level of phosphorus supplementation, calbindin and vitamin D receptor reached their highest expression.

Neonatal vitamin A injection promotes cattle muscle growth and increases oxidative muscle fibers

Background: Vitamin A and its metabolite,retinoic acid(RA),are important regulators of cell differentiation and organ morphogenesis.Its impact on beef cattle muscle growth remains undefined.Method: Angus steer calves were administrated with 0(control) or 150,000 IU vitamin A(retinyl palmitate in glycerol,i.m.) per calf at birth and 1 month of age.At 2 months of age,a biopsy of the Biceps femoris muscle was obtained to analyze the immediate effects of vitamin A injection on myogenic capacity of muscle cells.The resulting steers were harvested at 14 months of age.Results: Vitamin A administration increased cattle growth at 2 months.At 2 months of age,Vitamin A increased PAX7 positive satellite cells and the expression of myogenic marker genes including PAX7,MYF5,MYOD and MYOG.Muscle derived mononuclear cells were further isolated and induced myogenesis in vitro.More myotubes and a higher degree of myogenesis was observed in vitamin A groups.Consistently,vitamin A increased Latissimus dorsi(LD) muscle fiber size at harvest.In addition,vitamin A increased the ratio of oxidative type I and type IIA fibers and reduced the glycolic type IIX fibers.Furthermore,we found that RA,a key bioactive metabolite of vitamin A,activated PPARGC1 A promoter,which explains the upregulated expression of PPARGC1 A in skeletal muscle.Conclusion: Vitamin A administration to neonatal calves enhanced postnatal muscle growth by promoting myogenesis and increasing satellite cell density,accompanied with a shift to oxidative muscle fibers.

低冰镍衍生的具有高结构稳定性和快速扩散动力学的钠离子掺杂层状LiNi1/3Co1/3Mn1/3O2正极

通过共沉淀法合成钠离子(Na^(+))掺杂的高稳定性Li_(1−x)NaxNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM-Na)正极材料。首先论证采用低冰镍提取镍作为合成材料镍源的可行性。其次,在化学试剂合成的NCM(Ni,Co,Mn)材料中预先引入最优含量的Na^(+),占据部分Li^(+)位点,实现具有更低Li^(+)/Ni^(2+)阳离子混排的稳定结构,从而提高其电化学性能。结果表明,当Na+掺杂量为1%(质量分数)(x=0.01)时,获得的NCM-Na正极材料在1C电流密度下,循环100次后容量保持率从76.84%提高至89.21%。特别是在5C大电流密度下,循环200次后,可逆放电比容量依然维持在110 mA·h·g^(-1)。这为杂原子掺杂耦合材料化冶金开发低成本、高性能锂离子电池三元LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)正极材料提供具有前景的策略。

Supplementation of amylase combined with glucoamylase or protease changes intestinal microbiota diversity and benefits for broilers fed a diet of newly harvested corn

Background: The effect of amylases combined with exogenous carbohydrase and protease in a newly harvested corn diet on starch digestibility, intestine health and cecal microbiota was investigated in broiler chickens.Methods: Two hunderd and eighty-eight 5-day-old female chickens were randomly divided into six treatments: a newly harvested corn-soybean meal diet(control); control supplemented with 1,500 U/g α-amylase(Enzyme A);Enzyme A + 300 U/g amylopectase + 20,000 U/g glucoamylase(Enzyme B); Enzyme B + protease 10,000 U/g(Enzyme C); Enzyme C + xylanase 15,000 U/g(Enzyme D); and Enzyme D + cellulase 200 U/g + pectinase 1,000 U/g(Enzyme E). Growth performance, starch digestibility, digestive organ morphology, and intestinal microbiota were evaluated in the birds at 16 and 23 d of age.Results: Compared with the control diet, supplementation with Enzyme A significantly decreased ileum lesion scoring at 16 d of age(P < 0.05); supplementation with Enzyme B or Enzyme C showed positive effects on ileal amylopectin and total starch digestibility(P < 0.05); Broilers fed with a diet supplemented with Enzyme D had a tendency to decrease body weight gain at 23 d. Enzyme E supplementation improved lesion scoring of jejunum and ileum at 16 d(P < 0.05), and increased ileal amylopectin or total starch digestibility at 23 d(P < 0.05).Supplementation of enzymes changed cecal microbiota diversity. High numbers of Campylobacter, Helicobacter and Butyricicoccus, Anaerostipes and Bifidobacterium, Sutterella and Odoribacter were the main genera detected in supplementations with Enzymes B, C, D, and E respectively.Conclusions: Supplementation with amylase combined with glucoamylase or protease showed a beneficial effect on starch digestibility and intestinal microbiota diversity, and increased growth of broilers fed with newly harvested corn.

Recent Progress in Atmospheric Chemistry Research in China: Establishing a Theoretical Framework for the “Air Pollution Complex”

Atmospheric chemistry research has been growing rapidly in China in the last 25 years since the concept of the“air pollution complex”was first proposed by Professor Xiaoyan TANG in 1997.For papers published in 2021 on air pollution(only papers included in the Web of Science Core Collection database were considered),more than 24000 papers were authored or co-authored by scientists working in China.In this paper,we review a limited number of representative and significant studies on atmospheric chemistry in China in the last few years,including studies on(1)sources and emission inventories,(2)atmospheric chemical processes,(3)interactions of air pollution with meteorology,weather and climate,(4)interactions between the biosphere and atmosphere,and(5)data assimilation.The intention was not to provide a complete review of all progress made in the last few years,but rather to serve as a starting point for learning more about atmospheric chemistry research in China.The advances reviewed in this paper have enabled a theoretical framework for the air pollution complex to be established,provided robust scientific support to highly successful air pollution control policies in China,and created great opportunities in education,training,and career development for many graduate students and young scientists.This paper further highlights that developing and low-income countries that are heavily affected by air pollution can benefit from these research advances,whilst at the same time acknowledging that many challenges and opportunities still remain in atmospheric chemistry research in China,to hopefully be addressed over the next few decades.

An approach to gas sensors based on tunable diode laser incomplete saturated absorption spectra

A spectral profile reconstruction method that can be applied to incomplete saturated-absorption spectra is proposed and demonstrated. Through simulation and theoretical calculation, it is proved that compared with the traditional wholeprofile fitting method, this new method can increase the concentration detection upper limit of a single absorption line by about 8.7 times. High-concentration water vapor is measured using TDLAS technology, the total water vapor pressure and the self-broadened half-width coefficient of the spectrum were simultaneously measured from incomplete saturatedabsorption spectra and compared with high-precision pressure sensors and the HITRAN databases. Their maximum relative deviations were about 4.63% and 9.10%, respectively. These results show that the spectral profile reconstruction method has great application potential for expanding the dynamic range of single-line measurements to higher concentrations,especially for in-situ online measurements under complex conditions, such as over large temperature and concentration dynamic ranges.

Effects of dietary phosphorous supplementation on laying performance,egg quality,bone health and immune responses of laying hens challenged with Escherichia coli lipopolysaccharide

Background: Phosphorus is an essential nutrient to maintain poultry health and performance. The objective of this study was to evaluate the effect of dietary phosphorus levels on egg production, egg quality, bone health, immune responses of laying hens challenged with Escherichia coli lipopolysaccharide.Methods: Three hundred laying hens at 28 wk were randomly divided into 2 dietary treatments with 10 replicates of 15 birds. The wheat-soybean based diets contained either 0.12% or 0.4% non-phytate phosphorus(NPP). At 32 wk of age, all the birds of each dietary treatment were injected into the abdomen with 1.5 mg/kg body weight(BW) of either LPS or saline once a day at 24-h intervals for continuous 9 d. The performance of laying hens was evaluated for 9 d. The eggs after the fifth injection were collected to value the egg quality. Three hours after the first injection, blood was collected to measure serum metabolite and immune response associated parameters.Three hours after the fifth injection, the hens were euthanized to obtain tibia, cecal tonsils and jejunum.Results: Compared with saline-injected hens, LPS-injected hens had lower feed intake and egg production(P < 0.05).Eggshell thickness, strength, albumin height and Haugh unit were significantly increased in LPS-injected hens compared with saline-injected hens(P < 0.05). Furthermore, laying hens challenged with LPS had lower villious height/crypt depth ration than those received saline. Serum calcium, phosphorus and SOD activities significantly decreased in the LPS-injected hens compared with the control(P < 0.05). LPS up-regulated expression of IL-1β, IL-6 and IL-10 in cecum, and serum concentration of MDA, IL-1β and IL-6(P < 0.05), whereas 0.40% dietary non-phytate phosphorus supplementation significantly increased(P < 0.05) villi height/crypt depth ratio, decreased(P < 0.05) serum MDA and IFN-γ concentration compared with the 0.12% non-phytate phosphorus group.Conclusion: In summary, this study demonstrates that 0.40% dietary non-phytate phosphorus supplementation significantly increased calcium and phosphorus levels of eggshell, increased villi height/crypt depth ratio, decreased serum MDA and IFN-γ concentration compared with the 0.12% non-phytate phosphorus groups. The results indicate that high level of dietary non-phytate phosphorus exerts a potential effect in alleviating systemic inflammation of LPSchallenged laying hens.

BaTiO_(3)/Polyurethane Dielectric Composites with Diels-Alder Bond for Improved Self-Healing Properties

In general,self-healing dielectric composites are mainly composed of polar hydrogen bonds,which have high hydrophilicity and are unsuitable for humid environment.Dielectric composite with Diels-Alder(D-A)bond contains covalent bonds,it can be adopted as an efficient self-healing material.Here,we construct self-healing barium titanate(BT)/polyurethane(PU)dielectric composites by adopting PU with D-A bond as matrix(BT/PU-DA).The prepared 10%BT/PU-DA composite exhibits superior self-healing ability than that of PUDA.Moreover,its dielectric constant can reach 9.3 with a loss of only 0.04 at 1000 Hz and maintain 93%repair efficiency of tensile strength.The experimental analysis suggests the introduction of D-A bond can enhance the thermostability and self-healing ability of BT/PU-DA composite.In addition,the incorporation of BT nanoparticles and D-A bond in the self-healing composite contributes to the lower dielectric loss and excellent tensile strength after healing.The adopted strategy is a promising and facile approach to develop highly efficient selfhealing dielectric material,which will be conducive to reuse and sustainable development of the electronic packaging material in aqueous medium or wet environment.

Collectively induced transparency and absorption in waveguide quantum electrodynamics with Bragg atom arrays

Collective quantum states, such as subradiant and superradiant states, are useful for controlling optical responses in many-body quantum systems. In this work, we study novel collective quantum phenomena in waveguide-coupled Bragg atom arrays with inhomogeneous frequencies.For atoms without free-space dissipation, collectively induced transparency is produced by destructive quantum interference between subradiant and superradiant states. In a large Bragg atom array, multi-frequency photon transparency can be obtained by considering atoms with different frequencies. Interestingly, we find collectively induced absorption(CIA) by studying the influence of free-space dissipation on photon transport. Tunable atomic frequencies nontrivially modify decay rates of subradiant states. When the decay rate of a subradiant state equals to the free-space dissipation, photon absorption can reach a limit at a certain frequency. In other words, photon absorption is enhanced with low free-space dissipation, distinct from previous photon detection schemes. We also show multi-frequency CIA by properly adjusting atomic frequencies. Our work presents a way to manipulate collective quantum states and exotic optical properties in waveguide quantum electrodynamics(QED) systems.

Recent Advances in Electrochemical-Based Silicon Production Technologies with Reduced Carbon Emission

Sustainable and low-carbon-emission silicon production is currently one of the main focuses for the metallurgical and materials science communities.Electrochemistry,considered a promising strategy,has been explored to produce silicon due to prominent advantages:(a)high electricity utilization efficiency;(b)low-cost silica as a raw material;and(c)tunable morphologies and structures,including films,nanowires,and nanotubes.This review begins with a summary of early research on the extraction of silicon by electrochemistry.Emphasis has been placed on the electro-deoxidation and dissolution–electrodeposition of silica in chloride molten salts since the 21st century,including the basic reaction mechanisms,the fabrication of photoactive Si films for solar cells,the design and production of nanoSi and various silicon components for energy conversion,as well as storage applications.Besides,the feasibility of silicon electrodeposition in room-temperature ionic liquids and its unique opportunities are evaluated.On this basis,the challenges and future research directions for silicon electrochemical production strategies are proposed and discussed,which are essential to achieve large-scale sustainable production of silicon by electrochemistry.

数字金融创新对经济高质量发展的影响研究

在数字化时代,金融领域变革深刻,数字金融创新成全球经济关键驱动。信息技术发展使大数据等新兴技术与金融深度融合,数字金融打破传统边界,重塑服务生态。这种创新改变金融机构运营和服务模式,对经济高质量发展影响深远。它提高金融服务效率、支持实体经济、优化资源配置、增强风险防控,在多维度与经济高质量发展紧密相连。本文深入研究其影响,旨在为金融领域提供建议。数字金融创新提升效率体现在简化流程、加快资金流转等方面。对实体经济支持包括为企业提供融资渠道、推动产业升级等。在风险防控上,能精准分析和预警风险。通过案例可看到其对企业融资、产业发展和区域经济繁荣的积极作用。未来需加强科技创新,重视风险防控和监管,完善基础设施建设,加强人才培养和国际合作交流,以推动经济高质量可持续发展。

基于自适应深度射线树的WLAN室内目标入侵检测算法

由于无线局域网(wireless local area network, WLAN)的广泛部署和智能终端对WLAN协议的普遍支持,本文提出一种基于自适应深度射线树的WLAN室内目标入侵检测算法,其利用现有WLAN基础设施即可实现未携带任何信号收发设备的室内目标的入侵检测.为此,首先建立基于自适应深度射线树的准三维射线追踪模型,对室内静默和入侵状态下的接收信号强度(received signalstrength, RSS)传播特性进行建模;其次,联合RSS均值、方差、最大值、最小值、极差值和中位值6种信号特征构建概率神经网络(probabilistic neural network, PNN)的训练数据库;最后,利用训练得到的PNN对新采集RSS数据进行多分类判决,进而实现对室内目标的入侵检测与区域定位.实验结果表明,本文所提算法具有较高的入侵检测概率和较低的数据库构建开销.

室内Wi-Fi异步效应下CSI定位误差界估计方法

与传统的基于接收信号强度(received signal strength, RSS)的室内Wi-Fi定位方法相比,信道状态信息(channel state information, CSI)包含了信号传输过程中更细粒度和更多样化的物理层信息(如信道中各个子载波的振幅和相位信息),故基于CSI的室内Wi-Fi定位方法通常具有更高的定位精度.在利用CSI进行定位时,发送端采用正交频分复用(orthogonal frequency division multiplexing,OFDM)技术在多个正交子载波上并行发送数据并在接收端进行解调,但由于异步效应(如载波频率偏差(carrier frequency offset, CFO)、采样时钟频率偏差(sampling frequency offset, SFO)和符号定时偏差(symbol timing offset, STO))的存在,接收端子载波的正交性难以得到保证,于是,基于CSI的室内Wi-Fi定位方法的性能会因为符号间干扰(inter symbol interference, ISI)和载波间干扰(inter carrier interference, ICI)的影响而下降.对此,本文从频域的角度推导了不同异步效应下的CSI定位误差界以评估基于CSI的室内Wi-Fi定位性能.