基于空间位置关系的轨迹数据高效降维和查询算法

由于新型信息技术的快速发展,社会处于数字化、信息化转型的关键时期,各行业对于以数据库技术为基础的信息系统的需求也日益凸显.基于位置的服务依赖于海量实时生成的轨迹数据,在处理亿万级随时间连续变化的轨迹数据时,降维算法和查询技术一直是研究的关键,通过降低轨迹数据的规模,减少查询操作时处理数据的时间,能有效提升查询的性能,而能否实现高质量、高效率查询对于数据库而言至关重要.提出了面向轨迹数据的均匀网格编码,并在进一步优化后提出非均匀网格降维算法,将轨迹数据的坐标转化为1维字符串存储,对不符合要求的网格进行合并处理;通过空间位置映射充分保留轨迹数据间复杂的相互关系,并采用范围查询与最近邻查询对降维后的数据进行性能测试.实验使用不同城市真实轨迹数据与模拟生成轨迹数据作为数据集,将提出的均匀网格算法、非均匀网格算法与3种基准方法进行对比.实验证明,优化后的非均匀网格算法降维后数据的空间位置关系相似度可高达82.50%,范围查询时间较其他查询时间提升了至少73.86%,最近邻查询时间提升了至少52.26%,与其他基准方法相比取得了更好的效果.

Insights into Formation and Li-Storage Mechanisms of Hierarchical Accordion-Shape Orthorhombic CuNb_(2)O_(6) toward Lithium-Ion Capacitors as an Anode-Active Material

The orthorhombic CuNb_(2)O_(6)(O-CNO)is established as a competitive anode for lithium-ion capacitors(LICs)owing to its attractive compositional/structural merits.However,the high-temperature synthesis(>900℃)and controversial charge-storage mechanism always limit its applications.Herein,we develop a low-temperature strategy to fabricate a nano-blocks-constructed hierarchical accordional O-CNO framework by employing multilayered Nb_(2)CT_(x)as the niobium source.The intrinsic stress-induced formation/transformation mechanism of the monoclinic CuNb_(2)O_(6)to O-CNO is tentatively put forward.Furthermore,the integrated phase conversion and solid solution lithium-storage mechanism is reasonably unveiled with comprehensive in(ex)situ characterizations.Thanks to its unique structural merits and lithium-storage process,the resulted O-CNO anode is endowed with a large capacity of 150.3 mAh g^(-1)at 2.0 A g^(-1),along with long-duration cycling behaviors.Furthermore,the constructed O-CNO-based LICs exhibit a high energy(138.9 Wh kg^(-1))and power(4.0 kW kg^(-1))densities with a modest cycling stability(15.8%capacity degradation after 3000 consecutive cycles).More meaningfully,the in-depth insights into the formation and charge-storage process here can promote the extensive development of binary metal Nb-based oxides for advanced LICs.

以全蛋为原料制备双蛋白发酵乳工艺优化

采用单因素试验和正交试验法研制双蛋白发酵乳。结果表明:鸡蛋酶解液、豆浆、牛奶体积比为1∶3∶1时效果较好;蔗糖添加量为7%(质量分数)、发酵菌接种量为10%、发酵温度为43℃、发酵时间5 h时制备发酵乳感官评分较高,为90.68±0.11。向双蛋白发酵乳中添加D⁃异抗坏血酸钠0.10%、β⁃环糊精0.20%、羧甲基纤维素钠0.15%、卡拉胶0.10%时制得成品,感官评分较高,为95.42±0.45。产品理化分析结果为持水率(57.45±0.06)%,酸度(83.67±0.57)°T,脂肪含量(2.66±0.04)g/100 g,非脂肪固体含量(9.22±0.06)g/100 g,蛋白质含量(2.60±0.01)g/100 g,多肽含量(0.45±0.01)mg/g,符合GB 19302—2010《食品安全国家标准发酵乳》要求。

Generalized autoencoder-based fault detection method for traction systems with performance degradation

Fault diagnosis of traction systems is important for the safety operation of high-speed trains.Long-term operation of the trains will degrade the performance of systems,which decreases the fault detection accuracy.To solve this problem,this paper proposes a fault detection method developed by a Generalized Autoencoder(GAE)for systems with performance degradation.The advantage of this method is that it can accurately detect faults when the traction system of high-speed trains is affected by performance degradation.Regardless of the probability distribution,it can handle any data,and the GAE has extremely high sensitivity in anomaly detection.Finally,the effectiveness of this method is verified through the Traction Drive Control System(TDCS)platform.At different performance degradation levels,our method’s experimental results are superior to traditional methods.

湖北海棠叶化学成分及其应用研究进展

湖北海棠叶是2014年卫生部第20号公告批准的新食品原料,其研究价值主要集中于生物活性成分。基于此,本文归纳了现阶段国内外湖北海棠叶生物活性成分及其提取方法,并从生物活性成分、生理功能等方面综述相关研究进展,以期为湖北海棠叶的创新应用提供思路。

面向交通流预测的路况分级融合模型

针对复杂交通网的路况拥堵问题,提出了L^(2)(LSTM(Long Short-Term Memory)+LGBM(Light Gradient Boosting Machine))融合模型,为道路决策提供数据驱动的基础,优化交通调度,提高出行效率。首先,通过前向关联边结构存储路网模型;其次,提取历史序列数据特征,保留路网中的时序特征;最后,通过将时间序列数据与道路拓扑结构融合进行特征提取,训练模型并完成预测。为便于理解路段状态,采用分级评价,将预测结果划分为:拥堵、缓行和畅通。实验采用北京地区真实路况作为数据集,数据规模达1500余万条。实验将融合模型L^(2)与深度神经网络(DNN)、LSTM和LGBM做对比,实验结果表明,L^(2)的预测精度达91.22%,优于其他模型。最后,采用可视化技术展示实验结果,完成5种可视化图表的实现,便于用户直观理解道路的实时状态。

Percutaneous ultrasound and endoscopic ultrasound-guided biopsy of solid pancreatic lesions: An analysis of 1074 lesions

Backgrounds:Percutaneous ultrasound(US)and endoscopic ultrasound(EUS)-guided pancreatic biopsies are widely accepted in the diagnosis of pancreatic diseases.Studies comparing the diagnostic performance of US-and EUS-guided pancreatic biopsies are lacking.This study aimed to evaluate and compare the diagnostic yields of US-and EUS-guided pancreatic biopsies and identify the risk factors for inconclusive biopsies.Methods:Of the 1074 solid pancreatic lesions diagnosed from January 2017 to February 2021 in our center,275 underwent EUS-guided fine needle aspiration(EUS-FNA),and 799 underwent US-guided core needle biopsy(US-CNB/FNA).The outcomes were inconclusive pathological biopsy,diagnostic accuracy and the need for repeat biopsy.All of the included factors and diagnostic performances of both USCNB/FNA and EUS-FNA were compared,and the independent predictors for the study outcomes were identified.Results:The diagnostic accuracy was 89.8%for EUS-FNA and 95.2%for US-CNB/FNA(P=0.001).Biopsy under EUS guidance[odds ratio(OR)=1.808,95%confidence interval(CI):1.083-3.019;P=0.024],lesion size<2 cm(OR=2.069,95%CI:1.145-3.737;P=0.016),hypoechoic appearance(OR=0.274,95%CI:0.097-0.775;P=0.015)and non-pancreatic ductal adenocarcinoma carcinoma(PDAC)diagnosis(OR=2.637,95%CI:1.563-4.449;P<0.001)were identified as factors associated with inconclusive pathological biopsy.Hypoechoic appearance(OR=0.236,95%CI:0.064-0.869;P=0.030),lesions in the uncinate process of the pancreas(OR=3.506,95%CI:1.831-6.713;P<0.001)and non-PDAC diagnosis(OR=2.622,95%CI:1.278-5.377;P=0.009)were independent predictors for repeat biopsy.Biopsy under EUS guidance(OR=2.024,95%CI:1.195-3.429;P=0.009),lesions in the uncinate process of the pancreas(OR=1.776,95%CI:1.014-3.108;P=0.044)and hypoechoic appearance(OR=0.127,95%CI:0.047-0.347;P<0.001)were associated with diagnostic accuracy.Conclusions:In conclusion,both percutaneous US-and EUS-guided biopsies of solid pancreatic lesions are safe and effective;though the diagnostic accuracy of EUS-FNA is inferior to US-CNB/FNA.A tailored pancreatic biopsy should be considered a part of the management algorithm for the diagnosis of solid pancreatic disease.

Major complications after ultrasound-guided liver biopsy:An annual audit of a Chinese tertiary-care teaching hospital

BACKGROUND As ultrasound-guided percutaneous liver biopsy(PLB)has become a standard and important method in the management of liver disease in our country,a periodical audit of the major complications is needed.AIM To determine the annual incidence of major complications following ultrasoundguided PLB and to identify variables that are significantly associated with an increased risk of major complications.METHODS A total of 1857 consecutive cases of PLB were included in our hospital from January 2021 to December 2021.The major complication rate and all-cause 30-d mortality rate were determined.Multivariate analyses were performed by logistic regression to investigate the risk factors associated with major complications and all-cause 30-d mortality following ultrasound-guided PLB.RESULTS In this audit of 1857 liver biopsies,10 cases(0.53%)of major complications occurred following ultrasound-guided PLB.The overall all-cause mortality rate at 30 d after PLB was 0.27%(5 cases).Two cases(0.11%)were attributed to major hemorrhage within 7 d after liver biopsy.Fibrinogen less than 2 g/L[odds ratio(OR):17.226;95%confidence interval(CI):2.647-112.102;P=0.003],post-biopsy hemoglobin level(OR:0.963;95%CI:0.942-0.985;P=0.001),obstructive jaundice(OR:6.698;95%CI:1.133-39.596;P=0.036),application of anticoagulants/antiplatelet medications(OR:24.078;95%CI:1.678-345.495;P=0.019)and age(OR:1.096;95%CI:1.012-1.187;P=0.025)were statistically associated with the incidence of major complications after PLB.CONCLUSION In conclusion,the results of this annual audit confirmed that ultrasound-guided PLB can be performed safely,with a major complication rate within the accepted range.Strict patient selection and peri-biopsy laboratory assessment are more important than procedural factors for optimizing the safety outcomes of this procedure.

Advances and future directions in keloid research:Pathogenesis,diagnosis and personalized treatment strategies

Keloids,which are abnormal manifestations of wound healing,can result in significant functional impairment and aesthetic deformities.The pathogenesis of keloids is multifaceted and complex and influenced by various factors,such as genetics,the environment,and immune responses.The evolution of keloid treatment has progressed from traditional surgical excision to a contemporary combination of therapies including injection and radiation treatments,among others.This article provides a comprehensive review of keloid pathogenesis and treatment,emphasizing the latest advances in the field.Ultimately,this review underscores the necessity for continued research to enhance our understanding of keloid pathogenesis and to devise more effective treatments for this challenging condition.

Isolation and Screening of Lactic Acid Bacterial Strains with Antibacterial Properties from the Vaginas of Healthy Cows

In the present study, eight strains were isolated from 20 cow vagina samples and identified using phenotype, biochemical analysis, sugar fermentation tests, and 16S rRNA sequence analysis. Among eight strains, only SQ0048 was identified as Lactobacillus johnsonii based on a series of biochemical testing (including the adhesion test, catalase test, bacteriocin production test, antibacterial test, and pH value), suggesting that its biological activity was superior to the other seven strains. Furthermore, SQ0048 had the lowest pH value (4.32) and the shortest fermentation time (8 h) compared with the other strains. The adhesion rate of SQ0048 was significantly higher than that of Lactobacillus delbrueckii, with an average adhesion number of 304 ± 2.67. The hydrogen peroxide production testing in SQ0048 was positive;in addition, bacteriocin gene of SQ0048, encoding an approximately 10-kDa product, was successfully cloned, expressed, and detected using the SDS-PAGE method. Meanwhile, SQ0048 had a weak inhibitory effect on Staphylococcus aureus and Escherichia coli. However, the expression products of the bacteriocin gene of SQ0048 had a very strong inhibitory effect on S. aureus and E. coli, with inhibition zone sizes of 18 ± 0.45 mm and 15 ± 0.60 mm, respectively. These data showed that SQ0048 has excellent antibacterial properties compared with other isolated strains and is a potential probiotic candidate to improve the health of the vaginas of cows by inhibiting pathogenic microorganisms.

海藻酸钠-g-聚丙烯酰胺/氧化石墨烯复合水凝胶的制备及控释行为

以海藻酸、丙烯酰胺为单体,氧化石墨烯为原料制备了海藻酸钠-g-聚丙烯酰胺/氧化石墨烯(NaAlg-g-PAAm/GO)复合水凝胶,采用傅里叶变换红外光谱和扫描电镜对其结构和形貌进行了表征;当GO的质量分数从0.6%增至3.2%时,溶胀率从37%减至21%;阳离子对水凝胶的溶胀性的影响能力是Fe3+>Ca2+>K+;以5-氟尿嘧啶(5-FU)为抗癌药物模型,模拟胃腔和小肠的环境,研究了在pH=1.2和pH=7.4的缓冲溶液中复合水凝胶的控制释放行为,实验结果表明水凝胶在pH=7.4的缓冲溶液中的累积释放率明显高于在pH=1.2的溶液中的累积释放率,所以该类水凝胶有望成为靶向药物释放的载体。

晚期外伤性支气管断裂闭锁经支气管镜下介入治疗2例诊治体会

目的探讨晚期外伤性支气管断裂闭锁经支气管镜下介入治疗的可行性。方法采用支气管镜下微波、球囊扩张和冷冻等多种支气管镜下介入手段治疗,以期实现晚期外伤性支气管断裂闭锁的再通。结果2例晚期外伤性支气管断裂闭锁患者经支气管镜下介入治疗后,均实现了闭锁支气管的再通,明显改善了患者临床症状。结论支气管镜下介入治疗可有效实现晚期外伤性支气管断裂闭锁的再通,提供了一种新的治疗手段。

Highly active electrocatalysis of hydrogen evolution reaction in alkaline medium by Ni–P alloy: A capacitance-activity relationship

Different weights of amorphous Ni–P alloy with same P contents were electrodeposited on nickel plate with same area used as cathode for hydrogen evolution reaction(HER). The amorphous Ni–P alloy coatings were characterized for their surface morphology and composition through Scanning electron microscopy(SEM) and Energy dispersive X-ray spectroscopy(EDS) techniques, X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) analysis. The electrocatalytic activity for HER in alkaline medium is determined by linear scan voltammetry(LSV) and a relationship between HER activity and capacitance is established. The capacitance varies with the loading of the Ni–P on Ni plate but the activity for HER is directly proportional to the capacitance in alkaline and vice versa. 3#Ni–P/Ni containing 3.85 mg Ni–P alloy with highest capacitance performs the best catalytic activity. This work provides direct evidence to explore the capacitance influence on the electrocatalystic activity for the HER.

Prognostic values of optic nerve sheath diameter for comatose patients with acute stroke:An observational study

BACKGROUND Optic nerve sheath diameter(ONSD)measurement is one of the non-invasive methods recommended for increased intracranial pressure(ICP)monitoring.AIM This study aimed to evaluate the roles of optic nerve sheath diameter(ONSD)and ONSD/eyeball transverse diameter(ETD)ratio in predicting prognosis of death in comatose patients with acute stroke during their hospitalization.METHODS A total of 67 comatose patients with acute stroke were retrospectively recruited.The ONSD and ETD were measured by cranial computed tomography(CT)scan.All patients underwent cranial CT scan within 24 h after coma onset.Patients were divided into death group and survival group according to their survival status at discharge.The differences of the ONSD and ONSD/ETD ratio between the two groups and their prognostic values were compared.RESULTS The ONSD and ONSD/ETD ratio were 6.07±0.72 mm and 0.27±0.03 in the comatose patients,respectively.The ONSD was significantly greater in the death group than that in the survival group(6.32±0.67 mm vs 5.65±0.62 mm,t=4.078,P<0.0001).The ONSD/ETD ratio was significantly higher in the death group than that in the survival group(0.28±0.03 vs 0.25±0.02,t=4.625,P<0.0001).The area under the receiver operating characteristic curve was 0.760(95%CI:0.637-0.882,P<0.0001)for the ONSD and 0.808(95%CI:0.696-0.920,P<0.0001)for the ONSD/ETD ratio.CONCLUSION The mortality increased in comatose patients with acute stroke when the ONSD was>5.7 mm or the ONSD/ETD ratio was>0.25.Both indexes could be used as prognostic tools for comatose patients with acute stroke.The ONSD/ETD ratio was more stable than the ONSD alone,which would be preferred in clinical practice.

Synthesis,physical properties,and annealing investigation of new layered Bi-chalcogenide LaOBiHgS_3

The transport and thermoelectric properties together with annealing of the new layered Bi-chalcogenide LaOBiHgS_3 are studied. On the transport part, the insulating behavior of the as-grown sample is evidently depressed by post annealing.A hump-like abnormality appears around 170 K. The thermoelectric performance of the sample is observably improved by the annealing, mainly because of the enhanced electrical conductance. The present results suggest that the physical properties of LaOBiHgS_3 are sensitive to post annealing and the possible micro adjustments that follow, indicating the layered Bi-chalcogenide family to be an ideal platform for designing novel functional materials.

Anti-viral activity of Staphylococcus aureus lysates against herpes simplex virus type-Ⅰinfection:an in vitro and in vivo study

AIM:To investigate the effect of Staphylococcus aureus(S.aures)lysates(SALs)on herpes simplex virus type-Ⅰ(HSV1)infection in human corneal epithelial(HCE)cells and in a mouse model of HSV1 keratitis.METHODS:HCE,Vero,HeLa,and BV2 cells were infected with HSV1[HSV1f strain,HSV1f;HSV-1-H129 with green fluorescent protein(GFP)knock-in,HSV1g].Pre-or post-infection,SAL at various concentrations was added to the culture medium for 24 h.GFP fluorescence in HSV1g or plaque formation by HSV1f were examined.The effects of heat-treated SAL,precooled acetone-precipitated SAL,and SAL subjected to ultrafiltration(100 kDa)were evaluated.The effects of other bacterial components and lysates on HSV1 infection were also tested,including lipoteichoic acid(LTA),peptidoglycan(PGN),staphylococcal protein A(SPA),andα-hemolysin from S.aureus(α-toxin)as well as lysates from a wild-type S.aureus strain,S.epidermidis,and Escherichia coli(W-SAL,SEL,and ECL,respectively).In addition,SAL eye drops were applied topically to BALB/c mice with HSV1 keratitis,followed by in vivo observations.RESULTS:The cytopathic effect,plaque formation(HSV1f),and GFP expression(HSV1g)in infected cells were inhibited by SAL in a dose-dependent manner.The active component of SAL(≥100 kDa)was heat-sensitive and retained activity after acetone precipitation.In HSV1ginfected cells,treatment with LTA-sa,α-toxin,PGN-sa,or SPA did not inhibit GFP expression.SAL,W-SAL,and SEL(but not ECL)decreased GFP expression.In mice with HSV1 keratitis,SAL reduced corneal lesions by 71%.CONCLUSION:The results of this study demonstrate that SAL can be used to inhibit HSV1 infection,particularly keratitis.Further studies are needed to determine the active components and mechanism underlying the effects of SAL.

Application of Submerged Ultrafiltration in Pretreatment of Flue Gas Desulfurization Wastewater

Nowadays,the zero liquid discharge of flue gas desulfurization(FGD)wastewater from coal-fired units has attracted the attention of all countries in the world.The pretreatment methods generally have the problems of high operation cost,small treatment capacity,and poor flexibility.However,the membrane method can avoid the above problems.In the current research,it has not been found that someone directly uses submerged ultrafiltration to pretreat FGD wastewater.Therefore,this paper innovatively proposed to directly use ceramic ultrafiltration membrane to treat FGD wastewater,which can ensure effluent quality and improve the flexibility of the pretreatment system.In this paper,the performance of submerged ultrafiltration membrane for the filtration of FGD wastewater from a power plant was studied to optimize the filtration performance and improve the effluent quality.The effects of operating parameters such as membrane permeate flux,aeration rate and filtration/backwashing time combination on the membrane performance were studied.The results showed that when the filtration/backwashing time combination was 15 min/30 s,with the increased in permeate flux from 55 L/(m2·h)to 100 L/(m2·h),the steady transmembrane pressure(TMP)increased from 39 kPa to 70 kPa,and the fouling rate increased significantly from 4.5 kPa/h to 7.3 kPa/h;When the aeration rate increased from 10 m3/(m2·h)to 30 m3/(m2·h),the membrane pollution was much reduced.Excessive aeration rate cannot further alleviate the membrane pollution,but also brought greater energy consumption;Increasing backwashing time can effectively inhibit the formation of gel layer on the surface of the membrane and prolong the initial stage of low-pressure operation;The rejection of suspended solids(SS)and turbidity of the equipment studied in this paper can reach more than 99%under various working conditions,which can satisfy the water quality requirements of the subsequent steps.The submerged ultrafiltration membrane was suitable for the pretreatment of FGD wastewater because it can ensure the quality of permeate under the premise of long-term operation.

Detection of PRL-2 gene expression in hepatocellular carcinoma by real-time fluorescence quantitative PCR

Objective:To quantitatively detect the expression level of PRL-2 in primary hepatocellular carcinoma using real-time fluorescence quantitative PCR.Methods:Total RNA isolated from human HCC and liver tissue adjacent to the tumor was reversely transcribed into cDNA.Real-time fluorescence quantitative PCR(Q-PCR) method was used to analyze the expres-sion level of PRL-2 gene.Results:The Q-PCR method was performed successfully to precisely detect RNA level.PRL-2 was expressed in all portal vein tumor thrombosis(PVTT) and HCC,but only in some paratumor tissue.The highest expression level of PRL-2 gene was recorded in PVTT;meanwhile expression level of PRL-2 was higher than that in paratumor liver tis-sues and in HCC(P < 0.01),and it was higher in HCC than that in paratumor liver tissues.Conclusion:The Q-PCR may be the most precise method to quantitatively detect RNA level and can be used in gene expression changes.The PRL-2 gene has higher expression in PVTT than that in HCC and in paratumor liver tissue cells,indicating that it plays an important role in the development and metastasis of the HCC.

A study of medication rules of traditional Chinese medicine in the treatment of pre diabetes based on data mining

Background:To summarize the concerted application and prescription rules of traditional Chinese medicine in the treatment of pre diabetes.Methods:Microsoft Excel 2010 was used to summarize the categories,nature,flavour and channel tropism of drugs.The cluster analysis of high-frequency drugs was carried out by SPSS 22.0,and the association rules of high-frequency drugs were analyzed by Apriori algorithm provided by SPSS modeler 14.0.Results:One hundred and forty-six references were included,including 153 prescriptions and 131 drugs.Their frequency of use is listed in the following order.The top 3 categories of drugs were“Tonifying,Heat-Clearing”,diuresis and“Diffusing Dampness”drugs.The top 5 drugs were Huangqi(Astragali radix),Fuling(Poria),Huanglian(Coptidis rhizoma),Shanyao(Dioscoreae rhizoma),Gegen(Puerariae lobatae radix).The top 3 channel tropism of drugs were spleen,stomach and lung.The top 3 nature of drugs were cold,warm and calm.The top 3 flavour of drugs were sweet,bitter and pungent.The cluster analysis of high-frequency drugs showed that it could be classified into 4 categories:“Benefiting Qi”for promoting production of fluid,“Clearing Heat”and“Eliminating Dampness”,“Nourishing Yin”and“Clearing Heat”,and“Invigorating Spleen”for“Diffusing Dampness”.The results of association rule analysis showed that the combination with the highest degree of confidence and support was Poria-Chenpi(Citri reticulatae pericarpium)-Banxia(Pinelliae rhizoma)-Baizhu(Atractylodis macrocephalae rhizoma)and the combination with the highest frequency was Astragali radix-Puerariae lobatae radix.Conclusion:The pre diabetes is due to deficiency.The disease location is spleen and stomach and the pathological factor is phlegm-damp,that is why benefiting qi and invigorating spleen is regarded as the key link of clinical treatment.

Physicochemical difference of coffee beans with different species,production areas and roasting degrees

In recent decades,the demand for coffee has seen a continuous increase,and the aroma and flavor of coffee has been widely studied.The current research chose coffee beans of two species(Coffea arabica and C.canephora)from five production areas(Brazil,India,Indonesia,Uganda and Vietnam)with four different roasting degrees(medium light,medium,medium dark and dark),to investigate the difference on physicochemical properties.The results showed that Arabica coffee beans had higher concentrations of fat and organic acids,and total amount of volatile compounds,whereas Robusta beans had higher concentrations of protein.With the increase of roasting degree,the concentrations of protein,fat,organic acids,and the total amount of volatile compounds of coffee beans increased,while the concentrations of chlorogenic acid compounds decreased.The discriminant analysis indicated that the tested coffee beans could be clearly discriminated by species and roasting degrees,but not by production area.The results of this research conclude the physicochemical difference of Arabica and Robusta beans with different roasting degrees.The results can provide a theoretical basis for coffee bean selection for the relevant industries.