Effects of Charred Fructus Crataegi on the contractilily of isolated rat gastric and intestine muscle strips

Objective The purpose of the study is to investigate the effects of Charred Fructus Crataegi Alcohol Extract on contractililty of isolated rat gastric and intesting smooth muscle strips.Methods Isolated rat intestine was selected in the assay to test the effects of Charred Fructus Crataegi Alcohol Extract on contractilty of isolated rat gastric and intestine smooth muscle strips using Krebs' solution,to observe the effects of in the presence of acetylcholine or atropine.Results Charred Fructus Crataegi Alcohol Extract in the range of 2-8 mg crude drugs/mL could significantly reduce the contractility of rat gastric and intestine smooth muscle strips in a dose-dependent manner,and Charred Fructus Crataegi Alcohol Extract 8 mg·mL-1(crude drugs)could inhibit the stimulation induced by acetylcholine.Charred Fructus Crataegi Alcohol Extract 8 mg·mL-1(crude drugs)was found to have a inhibiton of the relaxtion concurrently used with atropin.Conclusions The results suggest that Charred Fructus Crataegi Alcohol Extract has prominent inhibitory effects on the contractile activity of isolated rat gastric and intestine smooth muscle strips.

High temperature dephosphorization behavior of monazite concentrate with charred coal

Dephosphorization behavior of monazite concentrate with charred coal at high temperature was investigated.It is found that the roast temperature is the main factor for the dephosphorization of the monazite.The high dephosphorization efficiency can be reached at the temperatures ranging from 1 200 to 1 400°C.When the monazite pellets,made by pressing mixture of the monazite,charred coal and water into mould,were roasted at 1 400°C for 2 h,98%of phosphorus was removed from the monazite pellets.The roast time has little effect on the dephosphorization efficiency.Meanwhile,the particle size of the charred coal also has great influence on the dephosphorization efficiency of the monazite,and it is better to control particle size around 150μm,while Fe and Fe2O3 have neglectable effect on the dephosphorization of the monazite.

拉萨市夏季含碳气溶胶的浓度水平与组成特征研究

利用颗粒物采样器采集拉萨市夏季(2021年8月30日~2021年9月23日)大气细颗粒物(PM_(2.5))样品,并对不同含碳气溶胶组分进行测定和探讨。根据碳组分挥发性的强弱,将有机碳(OC)分为易挥发组分(HOC)、中等挥发组分(MOC)和难挥发组分(LOC),元素碳(EC)分为焦碳(char)和烟炱(soot)。结果显示,拉萨市夏季大气环境白天OC和EC的平均浓度分别为4.39±0.98μg/m^(3)和1.09±0.69μg/m^(3),夜晚OC和EC的平均浓度分别为4.39±1.43μg/m^(3)和1.17±0.57μg/m^(3)。系统比较OC/EC和char/soot源示踪指标在源辨识上的差异,发现char/soot值比OC/EC值可以更准确地识别关键排放源对含碳气溶胶的影响,说明char/soot值是一个可靠的源解析工具。本研究测定的char/soot平均值为0.20,符合机动车尾气污染特征,远小于生物质燃烧和煤炭燃烧特征值,说明拉萨夏季大气环境主要受机动车尾气排放影响。LOC是拉萨夏季含碳气溶胶最丰富的OC组分,在所有碳组分中的占比为47.7%,其次为MOC(18.2%)和HOC(10.8%)。不同碳组分之间的相关性分析表明,HOC主要通过大气化学反应生成,未来可成为评估二次有机气溶胶的一个潜在指标。

Importance of oxygen-containing functionalities and pore structures of biochar in catalyzing pyrolysis of homologous poplar

Biochar and bio-oil are produced simultaneously in one pyrolysis process,and they inevitably contact and may interact,influencing the composition of bio-oil and modifying the structure of biochar.In this sense,biochar is an inherent catalyst for pyrolysis.In this study,in order to investigate the influence of functionalities and pore structures of biochar on its capability for catalyzing the conversion of homologous volatiles in bio-oil,three char catalysts(600C,800C,and 800AC)produced via pyrolysis of poplar wood at 600 or 800℃or activated at 800℃,were used for catalyzing pyrolysis of homologous poplar wood at 600℃,respectively.The results indicated that the 600C catalyst was more active than 800C and 800AC for catalyzing cracking of volatiles to form more gas(yield increase by 40.2%)and aromatization of volatiles to form more light or heavy phenolics,due to its abundant oxygen-containing functionalities acting as active sites.The developed pores of the 800AC showed no such catalytic effect but could trap some volatiles and allow their further conversion via sufficient aromatization.Nevertheless,the interaction with the volatiles consumed oxygen on 600C(decrease by 50%),enhancing the aromatic degree and increasing thermal stability.The dominance of deposition of carbonaceous material of a very aromatic nature over 800C and 800AC resulted in net weight gain and blocked micropores but formed additional macropores.The in situ diffuse reflectance infrared Fourier transform spectroscopy characterization of the catalytic pyrolysis indicated superior activity of 600C for removal of -OH,while conversion of the intermediates bearing C=O was enhanced over all the char catalysts.

Chemical Constituents in Charred Sanguisorbae Radix

Objective To study the chemical constituents in the effective fractions of charred Sanguisorbae Radix. Methods The compounds were isolated and purified by column chromatography and their structures were identified on the basis of physicochemical properties and spectral analysis. Results Five compounds were isolated and identified as 3β-hydroxy-28-norurs-17,19,21-trien (1), 3β-hydroxy-28-norurs-12,17-dien (2), 3β,19α-dihydroxyurs-13(18)- en-28-oic acid (3), 3β-[(α-L-arabin-opyranosyl) oxy]-28-norurs-12,17-dien (4), and pomolic acid (5). Conclusion Compounds 1, 3, and 4 are novel compounds belong to triterpenoids and triterpenoid saponins, named as sanguisorbigenins Z, Y1 , and Y2 , respectively.

A new approach to pedestal differentiation for soil loss estimation-a case study from a burnt area in north-central Portugal

Soil pedestals have long been used as qualitative indicators of soil splash erosion.In rangelands,plant-capped pedestals,generally grass tussocks,have also been used to quantitatively estimate soil loss since the first half of the twentieth century.In agricultural lands,forests,and bad-lands,stone-capped pedestals have been used as qualitative and semi-quantitative indicators of active,'extreme'erosion.Little work has been reported on using capstone pedestal data for quantifying soil loss.We postulate that three distinct capstone pedestal types may be present in any given location and that a detailed analysis of a pedestal height histogram may be used to recognize their populations.This analysis can subsequently inform if soil loss can be reliably estimated and if so,which of the existing methods using pedestal height data will provide more accurate results.The three proposed capstone pedestal types are:(1)neo-pedestals formed underneath surface stones exposed by(partial)removal of the soil surface cover;(2)endo-pedestals formed underneath stones that were buried in the soil but have been exposed by erosion;and(3)phoenix-pedestals formed underneath stones from collapsed pedestals.In the pedestal height histogram of any given location,a skew to smaller heights may indicate the existence of endo-and/or phoenix-pedestals,which may be revealed as a bi-(or tri)modal distribution when using a smaller bin size.This concept was applied to a case study where soil loss had been monitored for control plots and mulched plots during a 5-year period following wildfire in a eucalypt plantation.We measured pedestal heights and used methods to quantitatively assess soil loss from soil pedestal data in the available literature.Soil pedestal data at the end of the 5-year period under or overestimated soil loss in the control treatment,with results ranging from 60 to 115%of measured soil loss,depending on the method.It is postulated that phoenix-and endo-pedestals may be a driving factor behind the observed discrepancies.We discuss how future research may provide more insight into dominant processes,and how frequency distributions may be used to select the best methods for estimating soil loss from pedestals.

Ignition processes and characteristics of charring conductive polymers with a cavity geometry in precombustion chamber for applications in micro/nano satellite hybrid rocket motors

The arc ignition system based on charring polymers has advantages of simple structure,low ignition power consumption and multiple ignitions,which bringing it broadly application prospect in hybrid propulsion system of micro/nano satellite.However,charring polymers alone need a relatively high input voltage to achieve pyrolysis and ignition,which increases the burden and cost of the power system of micro/nano satellite in practical application.Adding conductive substance into charring polymers can effectively decrease the conducting voltage which can realize low voltage and low power consumption repeated ignition of arc ignition system.In this paper,a charring conductive polymer ignition grain with a cavity geometry in precombustion chamber,which is composed of PLA and multiwall carbon nanotubes(MWCNT)was proposed.The detailed ignition processes were analyzed and two different ignition mechanisms in the cavity of charring conductive polymers were revealed.The ignition characteristics of charring conductive polymers were also investigated at different input voltages,ignition grain structures,ignition locations and injection schemes in a visual ignition combustor.The results demonstrated that the ignition delay and external energy required for ignition were inversely correlated with the voltages applied to ignition grain.Moreover,the incremental depth of cavity shortened the ignition delay and external energy required for ignition while accelerated the propagation of flame.As the depth of cavity increased from 2 to 6 mm(at 50 V),the time of flame propagating out of ignition grain changed from 235.6 to 108 ms,and values of mean ignition delay time and mean external energy required for ignition decreased from 462.8 to 320 ms and 16.2 to 10.75 J,respectively.The rear side of the cavity was the ideal ignition position which had a shorter ignition delay and a faster flame propagation speed in comparison to other ignition positions.Compared to direct injection scheme,swirling injection provided a more favorable flow field environment in the cavity,which was beneficial to ignition and initial flame propagation,but the ignition position needed to be away from the outlet of swirling injector.At last,the repeated ignition characteristic of charring conductive polymers was also investigated.The ignition delay time and external energy required for ignition decreased with repeated ignition times but the variation was decreasing gradually.

Studies of Gas Emissions and Performance of Stoves Using Biomass

In this article,we evaluated the energy performance parameters and gas emissions to identify which of the stoves studied performs best,and the biomass char briquettes with less emission.Biomass char briquettes from peanut shells,cashew nut shells,and corn cobs were produced using wheat flour as a binder.The binder rate was set at 9%and 10%.Based on the energy performance parameters,it was highlighted that the char briquette from corn cob with 9%binder(Char_CC_9%)has the best energy performance,followed by the char briquette from peanut shells with 9%binder(Char_PNS_9%),and lastly,the char briquette from cashew nut shells with 10%binder(Char_CNS_10%).The average energy efficiency of the“jambar”stove was 15.68%,while that of the“Malgache”stove was 12.41%.The average specific fuel consumption of the“jambar”stove was 0.12 kg of fuel per kilogram of water while that of the“Malgache”stove was 0.15 kg of fuel per kilogram of water.In terms of gaseous emissions,CO(carbon monoxide)concentrations were very high for char briquettes from corn cobs,with a CO emission factor of 0.40 g/min and NOx emission factor of 9.79 mg/min.For char briquettes from cashew nut shells,CO and NOx emission factors were respectively 0.30 g/min and 5.32 mg/min.The lowest average concentrations were obtained with char briquettes from peanut shells with a CO emission factor of 0.25 g/min and NOx 3.98 mg/min.

Organic structure and possible origin of ancient charred paddies at Chuodun Site in southern China

A number of ancient charred paddies with a 14C dating of about 5900 a BP were recovered in the sixth excavation at Chuodun Site and are assigned to the Majiabang culture(7-6 ka BP).To understand their formation mechanism,the ancient charred paddies were compared to modern paddies using FT-IR spectrum and thermaogravimetric analysis.At the same time,modern charred paddies were made in helium by the laboratory method,and the structural characteristics of them and the ancient ones were revealed using CP/MAS-13C-NMR.Our results show there are more aromatic moieties in ancient charred paddies compared to modern paddies.The aliphatic components of modern charred paddies decrease continuously,accompanied by the accumulation of aromatic components,when the duration and temperature of oxidation increase,and the structure buildings of modern charred paddies are more similar to ancient ones.Given the planting manner of paddies during Majiabang culture period,these ancient charred paddies might be a result of the original farming mode involving fire.

Facile modification of aluminum hypophosphate and its flame retardancy for polystyrene

A phosphorus-containing flame retardant, aluminum hypophosphite(AHPi), has been modified by(3-aminopropyl) triethoxysilane(KH550) to prepare flame-retardant polystyrene(PS). The influence of modified AHPi on the morphology and characterization was investigated, and differences in flame retardant properties of the PS/AHPi and PS/modified AHPi were compared. The PS composite can pass the vertical burning tests(UL-94 standard) with a V-0 rating when the mass content of modified AHPi reaches20%, compared with the mass content of 25% AHPi. The element mapping of the PS composite shows that modified AHPi has better dispersion in PS than AHPi. Thermogravimetric analysis results indicated that adding modified AHPi can advance the initial decomposition temperature of the composite material.With the addition of modified AHPi, the decrease in peak heat release rate(p HRR) is more evident than AHPi, and the char yield of the resultant PS composites gradually increased. With the addition of 25%modified AHPi, the p HRR and total heat release of PS composites decreased by 81.4% and 37.6%. The modification of AHPi promoted its dispersion in the PS matrix and improved the char formation of PS composites. The results of real-time infrared spectrometry of PS composites, Fourier transform infrared spectra and X-ray photoelectron analysis of the char layer indicated that modified AHPi has flame retardancy in condensed and gas phases.

Regulating the Localization of Intumescent Flame Retardant for Improving the Flame Retardancy of Ethylene-vinyl Acetate Copolymer Using Polyamide 6 as a Charring Agent

Polyamide 6 (PA6) was employed as a charring agent of intumescent flame retardant (IFR) to improve the flame retardancy of ethylene-vinyl acetate copolymer (EVA). Different processing procedures were used to regulate the localization of IFR in the EVA matrix. Localizations in which IFR was dispersed in the PA6phase or in the EVA phase were prepared. The effect of the localization of IFR on the flame retardancy of EVA was investigated. The limited oxygen index (LOI), vertical burning (UL 94) and cone calorimeter test (CCT)showed that the localization of IFR in the EVA matrix exhibited a remarkable influence on the flame retardancy.Compared with EVA/IFR, a weak improvement in the flame retardancy was observed in the EVA/PA6/IFR blend withthe localization of IFR in the PA6 phase. When IFR was regulated from the PA6 phase to the EVA matrix,a remarkable increase in the flame retardancy was exhibited. The LOI was increased from 27.8%to 32.7%, and the UL 94 vertical rating was increased from V-2 to V-0. Moreover, an approximately 41.36%decrease in the peak heat release rate was exhibited. A continuous and compact intumescent charring layer that formed in the blends with the localization of IFR in the EVA matrix should be responsible for its excellent flame retardancy.

A Novel Siamese Network for Few/Zero-Shot Handwritten Character Recognition Tasks

Deep metric learning is one of the recommended methods for the challenge of supporting few/zero-shot learning by deep networks.It depends on building a Siamese architecture of two homogeneous Convolutional Neural Networks(CNNs)for learning a distance function that can map input data from the input space to the feature space.Instead of determining the class of each sample,the Siamese architecture deals with the existence of a few training samples by deciding if the samples share the same class identity or not.The traditional structure for the Siamese architecture was built by forming two CNNs from scratch with randomly initialized weights and trained by binary cross-entropy loss.Building two CNNs from scratch is a trial and error and time-consuming phase.In addition,training with binary crossentropy loss sometimes leads to poor margins.In this paper,a novel Siamese network is proposed and applied to few/zero-shot Handwritten Character Recognition(HCR)tasks.The novelties of the proposed network are in.1)Utilizing transfer learning and using the pre-trained AlexNet as a feature extractor in the Siamese architecture.Fine-tuning a pre-trained network is typically faster and easier than building from scratch.2)Training the Siamese architecture with contrastive loss instead of the binary cross-entropy.Contrastive loss helps the network to learn a nonlinear mapping function that enables it to map the extracted features in the vector space with an optimal way.The proposed network is evaluated on the challenging Chars74K datasets by conducting two experiments.One is for testing the proposed network in few-shot learning while the other is for testing it in zero-shot learning.The recognition accuracy of the proposed network reaches to 85.6%and 82%in few-and zero-shot learning respectively.In addition,a comparison between the performance of the proposed Siamese network and the traditional Siamese CNNs is conducted.The comparison results show that the proposed network achieves higher recognition results in less time.The proposed network reduces the training time from days to hours in both experiments.

日本酚氧化酶的分离纯化及其部分生物化学性质研究

利用离子交换层析和凝胶过滤层析等方法,从日本(Charybdis japonica)血淋巴中分离纯化出了酚氧化酶,并以L-二羟苯丙氨酸(L-DOPA)作为特异性底物对其生化性质和酶性质进行了研究。结果表明,酚氧化酶和酚氧化酶原的分子质量分别为64.5 ku和69.5 ku。以L-DOPA为底物对酚氧化酶纯品进行研究发现,其最适pH值为6.0、最适温度为40℃。对底物L-DOPA和儿茶酚的米氏常数Km值分别为3.41和7.97 mmol/L。该酶对亚硫酸钠、苯硫脲极为敏感,对硫脲、苯甲酸非常敏感,表明该酶很可能是一种儿茶酚酶型的酶。此外,EDTA,DETC,Zn2+,Mg2+和Cu2+均能显著抑制该酶活性,且10 mmol/L Cu2+能有效地回复该酶被DETC所抑制的酶活性,表明该酶确为一种Cu-金属酶。

有机锡氧羧酸簇合物[PhCH_2Sn(O)(O_2CCH=CHAr)]_6的合成、表征和[PhCH_2Sn(O)(O_2CCH=CHPh)]_6的晶体结构

利用 [(PhCH2 ) 3 Sn] 2 O与ArCHCHCO2 H反应 ,合成 6个新的 [PhCH2 Sn(O) (O2 CCHCHAr) ] 6簇合物 .通过元素分析、红外光谱和X射线单晶衍射对其结构进行了表征 .用X射线单晶衍射测定了 [PhCH2 Sn(O) (O2 CCHCHPh) ] 6的晶体结构 ,结果表明 ,该簇合物为三斜晶系 ,空间群P1- ,a =1 6 771(3)nm ,b =1 80 2 0 (4)nm ,c =2 10 73(4)nm ,α =10 8 111(3)° ,β =10 3 6 14 (3)° ,γ =10 4 6 79(3)° ,Z =2 ,V =5 5 0 33(18)nm3 ,Dc=1 35 0g/cm3 ,μ =1 396mm-1,F(0 0 0 ) =2 2 0 8,R =0 0 6 0 6 ,wR =0 .6 98.该化合物为鼓型簇状结构 ,锡原子呈畸变的八面体构型 .

Ablation characteristics of insulator under high-temperature gas dual-pulse erosion

This study numerically simulated and investigated the flow field characteristics of a typical dual-pulse solid rocket motor with a soft pulse separation device through thermal insulation ablation under high-temperature dual-pulse erosion.The ablation rate of ethylene-propylene-diene monomer(EPDM)insulator was measured after the experiment.Experimental results were analyzed through scanning electron microscopy and microcomputed tomography.The ablation mechanism of the EPDM insulator under the operation conditions of a dual-pulse solid rocket motor was evaluated by analyzing the results.The results reveal that the internal flow field of the motor with a soft pulse separation device is uniform.The original charred layer existing on the EPDM insulator surface in the first pulse combustor is the decisive factor affecting the final ablation rate of the dual-pulse motor during the second pulse operation,and the ablation characteristic region is easily formed with the exfoliation of the charred layer.The ablation rate difference of the insulator increases with gas velocity.

Hydrogen Production From Crude Bio-oil and Biomass Char by Electrochemical Catalytic Reforming

We reports an efficient approach for production of hydrogen from crude bio-oil and biomass char in the dual fixed-bed system by using the electrochemical catalytic reforming method. The maximal absolute hydrogen yield reached 110.9 g H2/kg dry biomass. The product gas was a mixed gas containing 72%H2, 26%CO2, 1.9%CO, and a trace amount of CH4. It was observed that adding biomass char （a by-product of pyrolysis of biomass） could remarkably increase the absolute H2 yield （about 20%-50%）. The higher reforming temperature could enhance the steam reforming reaction of organic compounds in crude bio-oil and the reaction of CO and H20. In addition, the CuZn-Al2O3 catalyst in the water-gas shift bed could also increase the absolute H2 yield via shifting CO to CO2.

信号流图在配电网潮流计算中的应用

为了解决采用传统方法进行配电网潮流计算所面临的实际困难,提出了基于流图理论求解线性方程的配电网潮流计算新方法,避免了繁琐的矩阵运算,提高了计算精度,克服了传统算法不适用的配电网特殊环境带来的影响,且该方法不存在计算的收敛性问题及其多解问题,避免了传统的潮流方法的纯“数值计算”所带来的各种误差。

面向数字人文的古诗文本情感术语抽取与应用研究

在跨学科知识范式下,数字人文的研究范畴随着自身学科体系的拓展而不断泛化,采取关键语义技术解析文化对象中的人文内涵与情感知识对于重拾学科"人文性"与"计算性"特质具有重要意义。本文以古诗文本为例,面向汉语诗文及其鉴赏实现大规模人文情感术语的自动化抽取与分析。首先在无标注集环境下提出一种基于"冷启动"的字序列自动标引方法来获取学习语料,随后在字向量(Char2Vec)指导下将汉字特征(部首、拼音等)和BERT语言学模型分别引入机器学习与深度学习模型,并从知识发现的角度定义新术语识别规则。研究发现,将现代鉴赏融入古诗原文显著优化了情感知识的广度与深度,领域术语能够被有效标引。训练的BERT-BiLSTM-CRFs深度学习模型的效果明显优于CRFs机器学习,最佳F1与F1distinct可分别达到95.63%和85.43%;同时汉字特征的引入也有效提升了传统CRFs效果,以领域特征和基于"竖心旁""心字底"部首约束特征为最优。相较于机器学习抽取出的长篇幅新术语,深度学习能够拓展出更多寄托情感知识的新意象词。源于诗文与鉴赏的情感术语为文学信息资源的情感分析与知识服务提供了参考(人文性),基于汉字语言特征的抽取方案为中文领域自然语言处理技术的深化提供了启迪(计算性)。

An exemplification of the Evolving Process by Studying the Chinese Character Mao

This paper tries to demarcate the evolving process of decategorization into three periods and exemplify it by studying the Chinese character Mao.The exemplification shows the correctness of the demarcation.