Smart materials for safe lithium-ion batteries against thermal runaway

In recent years,the new energy storage system,such as lithium ion batteries(LIBs),has attracted much attention.In order to meet the demand of industrial progress for longer cycle life,higher energy density and cost efficiency,a quantity of research has been conducted on the commercial application of LIBs.However,it is difficult to achieve satisfying safety and cycling performance simultaneously.There may be thermal runaway(TR),external impact,overcharge and overdischarge in the process of battery abuse,which makes the safety problem of LIBs more prominent.In this review,we summarize recent progress in the smart safety materials design towards the goal of preventing TR of LIBs reversibly from different abuse conditions.Benefiting from smart responsive materials and novel structural design,the safety of LIBs can be improved a lot.We expect to provide a comprehensive reference for the development of smart and safe lithium-based battery materials.

Coastal hypoxia response to the coupling of catastrophic flood,extreme marine heatwave and typhoon:a case study off the Changjiang River Estuary in summer 2020

Massive bodies of low-oxygen bottom waters are found in coastal areas worldwide,which are detrimental to coastal ecosystems.In summer 2020,the response of coastal hypoxia to extreme weather events,including a catastrophic flooding,an extreme marine heatwave,and Typhoon Bavi,is investigated based on multiple satellite,four cruises,and mooring observations.The extensive fan-shaped hypoxia zone presents significant northward extension during July-September 2020,and is estimated as large as 13 000 km^(2) with rather low oxygen minimum(0.42 mg/L) during its peak in 28-30 August.This severe hypoxia is attributed to the persistent strong stratification,which is indicated by flood-induced larger amount of riverine freshwater input and subsequent marine heatwave off the Changjiang River Estuary.Moreover,the Typhoon Bavi has limited effect on the marine heatwave and coastal hypoxia in summer 2020.

Influences of lithofacies on fluid mobility in mixed sedimentary rocks:Insights from NMR analysis of the middle Permian Lucaogou Formation,Junggar Basin

The multi-source mixed sedimentation resulted in a unique series of mixed fine-grained sedimentary rocks evolved within the Permian Lucaogou Formation in the Jimusar Sag,located in the southeastern Junggar Basin,China.The variety of lithofacies within this series resulted in pronounced heterogeneity of pore structures,complicating the analysis of fluid occurrence space and state within reservoirs.As a result,the impact of lithofacies on fluid mobility remains ambiguous.In this study,we employed qualitative methods,such as field emission scanning electron microscopy(FE-SEM)and thin section observation,and quantitative analyses,including X-ray diffraction(XRD),total organic carbon(TOC),vitrinite reflectance(Ro),high-pressure mercury intrusion(HPMI)porosimetry,and nuclear magnetic resonance(NMR),along with linear and grey correlation analyses.This approach helped delineate the effective pore characteristics and principal factors influencing movable fluids in the fine-grained mixed rocks of the Lucaogou Formation in the Jimusar Sag,Junggar Basin.The findings indicate the development of three fundamental lithologies within the Lucaogou Formation:fine sandstone,siltstone,and mudstone.Siltstones exhibit the highest movable fluid saturation(MFS),followed by fine sandstones and mudstones sequentially.Fluid mobility is predominantly governed by the content of brittle minerals,the sorting coefficient(Sc),effective pore connectivity(EPC),and the fractal dimension(D_(2)).High content of brittle minerals favors the preservation of intergranular pores and the generation of microcracks,thus offering more occurrence space for movable fluids.A moderate Sc indicates the presence of larger connecting throats between pores,enhancing fluid mobility.Elevated EPC suggests more interconnected pore throat spaces,facilitating fluid movement.A higher D_(2)implies a more intricate effective pore structure,increasing the surface area of the rough pores and thereby impeding fluid mobility.Ultimately,this study developed a conceptual model that illustrates fluid distribution patterns across different reservoirs in the Lucaogou Formation,incorporating sedimentary contexts.This model also serves as a theoretical framework for assessing fluid mobility and devising engineering strategies for hydrocarbon exploitation in mixed fine-grained sedimentary rocks.

Progress in the treatment of advanced hepatocellular carcinoma with immune combination therapy

Advanced hepatocellular carcinoma(HCC)is a severe malignancy that poses a serious threat to human health.Owing to challenges in early diagnosis,most patients lose the opportunity for radical treatment when diagnosed.Nonetheless,recent advancements in cancer immunotherapy provide new directions for the treatment of HCC.For instance,monoclonal antibodies against immune check-point inhibitors(ICIs)such as programmed cell death protein 1/death ligand-1 inhibitors and cytotoxic t-lymphocyte associated antigen-4 significantly improved the prognosis of patients with HCC.However,tumor cells can evade the immune system through various mechanisms.With the rapid development of genetic engineering and molecular biology,various new immunotherapies have been used to treat HCC,including ICIs,chimeric antigen receptor T cells,engineered cytokines,and certain cancer vaccines.This review summarizes the current status,research progress,and future directions of different immunotherapy strategies in the treatment of HCC.

Observed characteristics of flow,water mass,and turbulent mixing in the Preparis Channel

Preparis Channel is the very important exchange path of energy and materials between the northern Bay of Bengal and Andaman Sea(AS).A set of hydrographic measurements,a microstructure profiler,and a deep mooring were used to determine the characteristics of water masses,turbulent mixing,and flows in the Preparis Channel.The unprecedented short-term mooring data reveal that a deep current in the deep narrow passage(below 400 m)of the Preparis Channel flows toward the Bay of Bengal(BoB)with a mean along-stream velocity of 25.26 cm/s at depth of 540 m;above the deep current,there are a relatively weak current flows toward the AS with a mean along-stream velocity of 15.46 cm/s between 500 m and 520 m,and another weak current flows toward the BoB between 430 m and 500 m.Thus,a sandwiched vertical structure of deep currents(below 400 m)is present in the Preparis Channel.The volume transport below 400 m is 0.06 Sv(1 Sv=106 m^(3)/s)from the AS to the BoB.In the upper layer(shallower than 300 m),the sea water of the AS is relatively warmer and fresher than that in the BoB,indicating a strong exchange through the channel.Microstructure profiler observations reveal that the turbulent diffusivity in the upper layer of the Preparis Channel reaches O(10−4 m^(2)/s),one order larger than that in the interior of the BoB and over the continental slope of the northern AS.We speculate that energetic high-mode internal tides in the Preparis Channel contribute to elevated turbulent mixing.In addition,a local“hotspot”of turbidity is identified at the deep mooring site,at depth of about 100 m,which corresponds to the location of elevated turbulent mixing in the Preparis Channel.

Label-free breast cancer detection and classification by convolutional neural network-based on exosomes surface-enhanced raman scattering

Because the breast cancer is an important factor that threatens women's lives and health,early diagnosis is helpful for disease screening and a good prognosis.Exosomes are nanovesicles,secreted from cells and other body fluids,which can reflect the genetic and phenotypic status of parental cells.Compared with other methods for early diagnosis of cancer(such as circulating tumor cells(CTCs)and circulating tumor DNA),exosomes have a richer number and stronger biological stability,and have great potential in early diagnosis.Thus,it has been proposed as promising biomarkers for diagnosis of early-stage cancer.However,distinguishing different exosomes remain is a major biomedical challenge.In this paper,we used predictive Convolutional Neural model to detect and analyze exosomes of normal and cancer cells with surface-enhanced Raman scattering(SERS).As a result,it can be seen from the SERS spectra that the exosomes of MCF-7,MDA-MB-231 and MCF-10A cells have similar peaks(939,1145 and 1380 cm^(-1)).Based on this dataset,the predictive model can achieve 95%accuracy.Compared with principal component analysis(PCA),the trained CNN can classify exosomes from different breast cancer cells with a superior performance.The results indicate that using the sensitivity of Raman detection and exosomes stable presence in the incubation period of cancer cells,SERS detection combined with CNN screening may be used for the early diagnosis of breast cancer in the future.

Single-Cell RNA Sequencing Reveals Potential for Endothelial-to-Mesenchymal Transition in Tetralogy of Fallot

Background:Tetralogy of Fallot(TOF)is a very common cyanotic congenital heart disease.Endothelial-to-mesenchymal transition(EndoMT)is recognized as a physiological mechanism involved in embryonic heart development and endothelial formation.However,there is still a gap in the reports related to the mechanism of EndoMT development in TOF.Methods:First,transcriptomic data of single cell nuclei of TOF and Donor were obtained based on the Gene Expression Omnibus(GEO)database,and the data were normalized and clus-tered by dimensionality reduction using the Seurat package.Subsequently,differentially expressed genes(DEGs)between TOF and Donor were screened using the“FindMarkers”function,and the gene sets of interest were enriched.Finally,to characterize the dynamics of EndoMT occurrence in TOF,we performed pseudotime cell tra-jectory inference as well as utilized SCENIC analysis to probe the gene regulatory networks(GRNs)dominated by transcription factors(TFs)in endothelial cells.Results:We identified a total of six cell clusters based on single-cell nuclear transcriptome data from TOF and Donor.We found that 611 genes with up-regulated expression within TOF showed conversion to mesenchyme.By subdividing endothelial cell subtypes,endothelial cells 2 were shown to be involved in cell adhesion,migration and extracellular matrix processes.Pseudo-time and SCENIC analyses showed that endothelial cell 2 has EndoMT potential.In addition,ERG and TEAD1 are TFs that play key reg-ulatory roles in this subtype,and both of their target genes are also highly expressed in TOF.This demonstrates that ERG and TEAD1 effectively promote the EndoMT process.Conclusion:Our study reveals the molecular mechanisms underlying the development of EndoMT in TOF,which demonstrates that manipulating the endothelial-to-mesenchymal transition may offer unprecedented therapeutic potential for the treatment of TOF.

Hydrocarbon generation mechanism of lamalginite- and telalginite-dominated source rocks in a saline lake basin: A case study of the Permian Lucaogou formation in the Jimusaer Sag, Junggar Basin

The hydrocarbon generation of source rocks is significantly influenced by organic matter type, chemical element composition, and structural characteristics of kerogen. We classified the organic matter types in the shale of the Lucaogou Formation, Jimusar Sag, Junggar Basin, using organic petrology and rock pyrolysis as well as kerogen element and Fourier transform infrared (FT-IR) spectroscopy analyses, and compared the hydrocarbon generation mechanisms of source rocks with different types of organic matter. The organic matter of the Lucaogou Formation contains mostly two types of hydrocarbon generating macerals, the lamalginite and the telalginite based on physical and optical properties (texture, fluorescence, and optical reflectance). The lamalginite is a continuous sheet of less than 5 μm thick and greater than 50 μm in length. It has strong yellow fluorescence. The telalginite occurs as discontinuous short strips or pear-shaped objects with length of 10–30 μm and relatively weak fluorescence. The lamalginite-dominated shale has higher atomic H/C and lower atomic O/C ratios, indicating better hydrocarbon generation potential, whereas the telalginite-dominated shale has higher N and S heteroatom contents. The results of FT-IR spectroscopy of the kerogen indicate that the lamalginite-dominated shale is rich in aliphatic groups with long linear methylene sequences. The aromatic groups content is relatively low, but the carboxyl/carbon group (Cdouble bondO) content is high. The aliphatic group content of the telalginite-dominated shale is relatively low, with short-branched chains. The aromatic group content is relatively high. The methyl vibration signal directly connected to the benzene ring is strong, and the sulfoxide (Sdouble bondO) group has a high-intensity peak. Our results provide new insights into distinguishing organic matter types in the Lucaogou Formation and understanding the hydrocarbon generation mechanisms of source rocks in saline lake basins.

Inter-annual variations of dissolved oxygen and hypoxia off the northern Changjiang River(Yangtze River) Estuary in summer from 1997 to 2014

Hypoxia off the Changjiang River Estuary has been the subject of much attention,yet systematic observations have been lacking,resulting in a lack of knowledge regarding its long-term change and drivers.By revisiting the repeated surveys of dissolved oxygen(DO) and other relevant hydrographic parameters along the section from the Changjiang River Estuary to the Jeju-do in the summer from 1997 to 2014,rather different trends were revealed for the dual low-DO cores.The nearshore low-DO core,located close to the river mouth and relatively stable,shows that hypoxia has become more severe with the lowest DO descen ding at a rate of -0.07 mg/(L·a) and the thickness of low-DO zone rising at a rate of 0.43 m/a.The offshore core,centered around 40-m isobath but moving back and forth between 123.5°-125°E,shows large fluctuations in the minimum DO concentration,with the thickness of low-DO zone falling at a rate of -1.55 m/a.The probable factors affecting the minimum DO concentration in the two regions also vary.In the nearshore region,the decreasing minimum DO is driven by the increase in both stratification and primary productivity,with the enhanced extension of the Changjiang River Diluted Water(CDW) strengthening stratification.In the offshore region,the fluctuating trend of the minimum DO concentration indicates that both DO loss and DO supplement are distinct.The DO loss is primarily attributed to bottom apparent oxygen utilization caused by the organic matter decay and is also relevant to the advection of low-DO water from the nearshore region.The DO supplement is primarily due to weakened stratification.Our analysis also shows that the minimum DO concentration in the nearshore region was extremely low in 1998,2003,2007 and 2010,related to El Ni?o signal in these summers.

Radix Ilicis Pubescentis total flavonoids combined with mobilization of bone marrow stem cells to protect against cerebral ischemia/reperfusion injury

Previous studies have shown that Radix Ilicis Pubescentis total flavonoids have a neuroprotective effect, but it remains unclear whether Radix Ilicis Pubescentis total flavonoids have a synergistic effect with the recombinant human granulocyte colony stimulating factor-mobilized bone marrow stem cell transplantation on cerebral ischemia/reperfusion injury. Rat ischemia models were administered 0.3, 0.15 and 0.075 g/kg Radix Ilicis Pubescentis total flavonoids from 3 days before modeling to 2 days after injury. Results showed that Radix Ilicis Pubescentis total flavonoids could reduce pathological injury in rats with cerebral ischemia/reperfusion injury. The number of Nissl bodies increased, Bax protein expression decreased, Bcl-2 protein expression increased and the number of CD34-positive cells increased. Therefore, Radix Ilicis Pubescentis total flavonoids can improve the bone marrow stem cell mobilization effect, enhance the anti-apoptotic ability of nerve cells, and have a neuroprotective effect on cerebral ischemia/reperfusion injury in rats.

Indirect somatic embryogenesis and regeneration of Fraxinus mandshurica plants via callus tissue

Somatic embryogenesis of Fraxinus mandshurica has the problems of low somatic embryo(SE) yield,unsynchronized SE development,and a high percentage of deformed SEs.We aimed to improve F.mandshurica SE production by synchronizing SE development,improving SE quality,and inducing root formation to obtain complete regenerated plants.Cotyledons of immature zygotic embryos of F.mandshurica were induced to form callus and then SEs.The SE induction percentage from explants differed among 32 mother trees,and the one with the highest SE induction percentage(29.8%) was used for further experiments.The highest callus induction percentage was94.2% on 1/2-strength Murashige and Skoog medium(MS1/2)supplemented with 0.15 mg·L^(-1) naphthalene acetic acid.The highest callus proliferation coefficient(240.5) was obtained on McCown's Woody Plant Medium containing 0.1 mg·L^(-1)6-benzyl adenine and 0.15 mg·L^(-1) 2,4-dichlorophenoxyacetic acid.The highest number of SEs(1020.5 g~(-1) fresh weight) was obtained on MS1/2 medium supplemented with1 mg·L^(-1) 6-benzyladenine.The highest number of cotyledon embryos(397/g fresh weight) was obtained by incubating materials on medium containing 1 mg·L^(-1) abscisic acid and then applying a drying treatment.The cotyledon embryos were milky white,uniformly sized(average length 4.7 mm),and 80% of them were normal.The SE rooting percentage on 1/2 MS medium containing 0.01 mg·L^(-1) NAA was 37.5%.Overall,the germination percentage of SEs was 26.4%,and complete regenerated plants were obtained after transplanting and acclimation.These results provide more possibilities for the preservation and breeding of F.mandshurica.

Risk prediction models for hepatocellular carcinoma in different populations

Hepatocellular carcinoma （HCC） is a malignant disease with limited therapeutic options due to its aggressive progression. It places heaW burden on most low and middle income countries to treat HCC patients. Nowadays accurate HCC risk predictions can help making decisions on the need for HCC surveillance and antiviral therapy. HCC risk prediction models based on major risk factors of HCC are useful and helpful in providing adequate surveillance strategies to individuals who have different risk levels. Several risk prediction models among cohorts of different populations for estimating HCC incidence have been presented recently by using simple, efficient, and ready-to-use parameters. Moreover, using predictive scoring systems to assess HCC development can provide suggestions to improve clinical and public health approaches, making them more cost-effective and effort-effective, for inducing personalized surveillance programs according to risk stratification. In this review, the features of risk prediction models of HCC across different populations were summarized, and the perspectives of HCC risk prediction models were discussed as well.

Comprehe nsive an alysis of SSRs and database construction using all complete gene-cod ing sequences in major horticultural and represe ntative plants

Simple sequence repeats(SSRs)are one of the most important genetic markers and widely exist in most species.Here,we identified 249,822 SSRs from 3,951,919 genes in 112 plants.Then,we conducted a comprehensive analysis of these SSRs and constructed a plant SSR database(PSSRD).Interestingly,more SSRs were found in lower plants than in higher plants,showing that lower plants needed to adapt to early extreme environments.Four specific enriched functional terms in the lower plant Chlam^tdomonas reinhardtii were detected when it was compared with seven other higher plants.In addition,Guanylate_cyc existed in more genes of lower plants than of higher plants.In our PSSRD,we constructed an interactive plotting function in the chart interface,and users can easily view the detailed information of SSRs.All SSR information,including sequences,primers,and annotations,can be downloaded from our database.Moreover,we developed Web SSR Finder and Batch SSR Finder tools,which can be easily used for identifying SSRs.Our database was developed using PHP,HTML,J avaScript,and MySQL,which are freely available at http://www.pssrd.info/.We conducted an analysis of the Myb gene families and flowering genes as two applications of the PSSRD.Further analysis indicated that whole-genome duplication and whole-genome triplication played a major role in the expansion of the Myb gene families.These SSR markers in our database will greatly facilitate comparative genomics and functional genomics studies in the future.

Thermal hazard assessment of TKX-50-based melt-cast explosive

In the present study, thermal hazards of TNT and DNAN used as the molten binder in TKX-50-based meltcast explosives were comparatively studied through accelerating rate calorimeter(ARC) and Cook-off experiments. Two kinds of ARC operation modes were performed to investigate the thermal safety performance under adiabatic conditions(HWS mode) and constant heating(CHR mode). The obtained results demonstrated that at both heating modes, DNAN/TKX-50 outperformed TNT/TKX-50 from the thermal safety point of view. However, the sensitivity to heat of the samples was reverse because of the different heating modes. In addition, the results of thermal hazard assessment obtained from the cookoff experiment complied with ARC analysis which indicated the molten binder TNT replaced by DNAN would reduce the hazard of the TKX-50 melt cast explosive. Furthermore, the results of cook-off experiments also showed that DNAN/TKX-50 outperformed TNT/TKX-50 from the aspect of thermal stability, which was consistent with the result of CHR mode because of the similar heating process.

Cost-Aware Multi-Domain Virtual Data Center Embedding

Virtual data center is a new form of cloud computing concept applied to data center. As one of the most important challenges, virtual data center embedding problem has attracted much attention from researchers. In data centers, energy issue is very important for the reality that data center energy consumption has increased by dozens of times in the last decade. In this paper, we are concerned about the cost-aware multi-domain virtual data center embedding problem. In order to solve this problem, this paper first addresses the energy consumption model. The model includes the energy consumption model of the virtual machine node and the virtual switch node, to quantify the energy consumption in the virtual data center embedding process. Based on the energy consumption model above, this paper presents a heuristic algorithm for cost-aware multi-domain virtual data center embedding. The algorithm consists of two steps: inter-domain embedding and intra-domain embedding. Inter-domain virtual data center embedding refers to dividing virtual data center requests into several slices to select the appropriate single data center. Intra-domain virtual data center refers to embedding virtual data center requests in each data center. We first propose an inter-domain virtual data center embedding algorithm based on label propagation to select the appropriate single data center. We then propose a cost-aware virtual data center embedding algorithm to perform the intra-domain data center embedding. Extensive simulation results show that our proposed algorithm in this paper can effectively reduce the energy consumption while ensuring the success ratio of embedding.

Stomatin plays a suppressor role in non-small cell lung cancer metastasis

Objective:Metastasis is one of the key causes of high mortality in lung cancer.Aberrant DNA methylation is a common event in metastatic lung cancer.We aimed to identify new epigenetic regulation of metastasis-associated genes and characterize their effects on lung cancer progression.Methods:We screened genes associated with non-small cell lung cancer(NSCLC)metastasis by integrating datasets from the Gene Expression Omnibus(GEO)database.We obtained epigenetic-regulated candidate genes by analyzing the expression profile of demethylation genes.By overlapping analysis,epigenetically modulated metastasis-associated genes were obtained.Kaplan-Meier plotter(KM plotter)was utilized to assess the overall survival(OS)of stomatin in lung cancer.Immunohistochemistry(IHC)was conducted to determine the association between stomatin and metastasis-associated clinical indicators.Both in vitro and in vivo assays were performed to investigate the potential role of stomatin in metastasis.The regulation mechanisms of transforming growth factorβ1(TGFβ1)on stomatin were determined by Sequenom MassARRAY quantitative methylation and western blot assays.Results:A series of bioinformatic analyses revealed stomatin as the metastasis-associated gene regulated by DNA methylation.The KM plotter analysis showed a positive association between stomatin and the OS of lung cancer.IHC analysis indicated that the decreased stomatin expression is linked with advanced TNM stage.Loss-and gainof-function experiments displayed that stomatin could inhibit the migration and invasion of NSCLC cells.Furthermore,TGFβ1 repressed stomatin expression during epithelial-to-mesenchymal transition(EMT).The negative correlation between stomatin and TGFβ1 was also validated in advanced stage III lung tumor samples.The underlying mechanism by which TGFβ1 inhibits stomatin is due in part to DNA methylation.Conclusions:Our results suggest that stomatin may be a target for epigenetic regulation and can be used to prevent metastatic diseases.

Spatial-Modulated Physical-Layer Network Coding Based on Block Markov Superposition Transmission for Maritime Relay Communications

As an alternative to satellite communications,multi-hop relay networks can be deployed for maritime long-distance communications.Distinct from terrestrial environment,marine radio signals are affected by many factors,e.g.,weather conditions,evaporation ducting,and ship rocking caused by waves.To ensure the data transmission reliability,the block Markov superposition transmission(BMST)codes,which are easily configurable and have predictable performance,are applied in this study.Meanwhile,the physical-layer network coding(PNC)scheme with spatial modulation(SM)is adopted to improve the spectrum utilization.For the BMST-SMPNC system,we propose an iterative algorithm,which utilizes the channel observations and the a priori information from BMST decoder,to compute the soft information corresponding to the XORed bits constructed by the relay node.The results indicate that the proposed scheme outperforms the convolutional coded SM-PNC over fast-fading Rician channels.Especially,the performance can be easily improved in high spatial correlation maritime channel by increasing the memory m.

Generalized Block Markov Superposition Transmission over Free-Space Optical Links

In free-space optical(FSO) communications, the performance of the communication systems is severely degraded by atmospheric turbulence. Channel coding and diversity techniques are commonly used to combat channel fading induced by atmospheric turbulence. In this paper, we present the generalized block Markov superposition transmission(GBMST) of repetition codes to improve time diversity. In the GBMST scheme, information sub-blocks are transmitted in the block Markov superposition manner, with possibly different transmission memories. Based on analyzing an equivalent system, a lower bound on the bit-error-rate(BER) of the proposed scheme is presented. Simulation results demonstrate that, under a wide range of turbulence conditions, the proposed scheme improves diversity gain with only a slight reduction of transmission rate. In particular, with encoding memory sequence(0, 0, 8) and transmission rate 1/3, a diversity order of eleven is achieved under moderate turbulence conditions. Numerical results also show that, the GBMST systems with appropriate settings can approach the derived lower bound, implying that full diversity is achievable.

基于HPLC指纹图谱结合化学模式识别评价侧柏叶的质量

目的 建立不同产地侧柏叶的HPLC指纹图谱,并采用化学模式识别评价侧柏叶质量。方法 采用HPLC法。以ZORBAX Eclipse plus-C18为色谱柱(250 mm×4.6 mm,5μm),以乙腈-0.1%磷酸溶液为流动相,梯度洗脱,流速:1.0 mL·min^(-1),检测波长:254 nm。利用中药色谱指纹图谱相似度评价系统(2012版)建立24批侧柏叶HPLC指纹图谱并进行相似度评价,结合混合对照品图谱确定共有峰。采用SPSS 25.0软件进行聚类分析。采用Simca-P软件进行主成分分析和偏最小二乘法-判别分析,并筛选影响侧柏叶质量的差异性成分。结果 侧柏叶指纹图谱中共有13个共有峰,与对照指纹图谱相比,除S2一批外,其余23批药材的相似度均高于0.92。并指认了杨梅苷、槲皮苷、异槲皮苷、穗花双黄酮4个共有峰。聚类分析结果显示24批药材聚为两类,S1、S3-S24聚为一类,同一产地的药材有较大差异,不同产地药材也有相似性;S2聚为一类为圆柏叶。主成分分析结果表明6类主成分的累计方差贡献率为88.412%,可以反映原始色谱峰大部分信息。偏最小二乘法判别分析筛选出5种成分,是24批药材产生质量差异的标志性成分。结论 所建HPLC指纹图谱方法操作简便、准确,结合化学模式识别可用于侧柏叶的质量控制。峰8等5个成分为影响侧柏叶质量的差异性成分。

Temperature field model in surface grinding: a comparative assessment

Grinding is a crucial process in machining workpieces because it plays a vital role in achieving the desired precision and surface quality.However,a significant technical challenge in grinding is the potential increase in temperature due to high specific energy,which can lead to surface thermal damage.Therefore,ensuring control over the surface integrity of workpieces during grinding becomes a critical concern.This necessitates the development of temperature field models that consider various parameters,such as workpiece materials,grinding wheels,grinding parameters,cooling methods,and media,to guide industrial production.This study thoroughly analyzes and summarizes grinding temperature field models.First,the theory of the grinding temperature field is investigated,classifying it into traditional models based on a continuous belt heat source and those based on a discrete heat source,depending on whether the heat source is uniform and continuous.Through this examination,a more accurate grinding temperature model that closely aligns with practical grinding conditions is derived.Subsequently,various grinding thermal models are summarized,including models for the heat source distribution,energy distribution proportional coefficient,and convective heat transfer coefficient.Through comprehensive research,the most widely recognized,utilized,and accurate model for each category is identified.The application of these grinding thermal models is reviewed,shedding light on the governing laws that dictate the influence of the heat source distribution,heat distribution,and convective heat transfer in the grinding arc zone on the grinding temperature field.Finally,considering the current issues in the field of grinding temperature,potential future research directions are proposed.The aim of this study is to provide theoretical guidance and technical support for predicting workpiece temperature and improving surface integrity.