Study on Processing of Clear Banana Juice Using Hot Water Extraction Method

In this study, the effects of hot water temperature on clarity, total soluble solids, polyphenol oxidase （PPO） and color of banana juice during hot water ex-traction were discussed based on the theory in which heat treatment might induce the pectin and protein in banana pulp to form insoluble products. The results showed the hot water temperature had a significant effect on the formation of insol-uble polymers in banana pulp from pectin and protein. In 75 ℃ water, the pectin and protein in banana pulp were most inclined to form insoluble products. Under this condition, the clarity of banana juice was also highest. The light transmittance at 660 nm was close to 90%. In the banana juice, extracted by 75 ℃ water, the pectin and protein contents were lowest, and they were lower than 7.3 mg/100 ml and 12.9 mg/100 ml respectively. The 75 ℃ water could not inactivate completely the pectin in banana pulp due to its high heat resistance, Therefore, 0.05% L-cys-teine or ascorbic acid needed to be added into banana pulp to inhibit the browning of juice induced by residual PPO.

Application of multi-scale feature extraction to surface defect classification of hot-rolled steels

Feature extraction is essential to the classification of surface defect images. The defects of hot-rolled steels distribute in different directions. Therefore, the methods of multi-scale geometric analysis （MGA） were employed to decompose the image into several directional subba^ds at several scales. Then, the statistical features of each subband were calculated to produce a high-dimensional feature vector, which was reduced to a lower-dimensional vector by graph embedding algorithms. Finally, support vector machine （SVM） was used for defect classification. The multi-scale feature extraction method was implemented via curvelet transform and kernel locality preserving projections （KLPP）. Experiment results show that the proposed method is effective for classifying the surface defects of hot-rolled steels and the total classification rate is up to 97.33%.

Large-scale physical simulation of injection and production of hot dry rock in Gonghe Basin,Qinghai Province,China

Based on the independently developed true triaxial multi-physical field large-scale physical simulation system of in-situ injection and production,we conducted physical simulation of long-term multi-well injection and production in the hot dry rocks of the Gonghe Basin,Qinghai Province,NW China.Through multi-well connectivity experiments,the spatial distribution characteristics of the natural fracture system in the rock samples and the connectivity between fracture and wellbore were clarified.The injection and production wells were selected to conduct the experiments,namely one injection well and two production wells,one injection well and one production well.The variation of several physical parameters in the production well was analyzed,such as flow rate,temperature,heat recovery rate and fluid recovery.The results show that under the combination of thermal shock and injection pressure,the fracture conductivity was enhanced,and the production temperature showed a downward trend.The larger the flow rate,the faster the decrease.When the local closed area of the fracture was gradually activated,new heat transfer areas were generated,resulting in a lower rate of increase or decrease in the mining temperature.The heat recovery rate was mainly controlled by the extraction flow rate and the temperature difference between injection and production fluid.As the conductivity of the leak-off channel increased,the fluid recovery of the production well rapidly decreased.The influence mechanisms of dominant channels and fluid leak-off on thermal recovery performance are different.The former limits the heat exchange area,while the latter affects the flow rate of the produced fluid.Both of them are important factors affecting the long-term and efficient development of hot dry rock.

Ultrasonic Sound Hot Extract—Ultraviolet Spectrophotometric Determination of Total Flavone in Comb Honey

[Objective] The aim was to establish a rapid method for the determination of the content of total flavonoids in the honey comb. [Method] The content of total flavonoids weas determined based on samples including comb honey, propolis, royal jelly, linden tree honey, with a polyamide column chromatography by spectrophotometry at 360 nm wavelength. [Result] The recovery rate of the method was above 90%, and the variation coefficient was lower than 2%. Compared with the traditional method, this method has less reagent consumption, simple operation and so on.[Conclusion] The content of total flavonoids in comb honey was 14.97 mg/100 g, although is only 0.87% of the total flavone content in propolis. The contained total flavonoids at least doubled than that of others and comb honey is more valuable in the content of flavonoids.

Extraction of indium from indium-zinc concentrates

A new process for extracting indium from indium-zinc concentrates was proposed.The process can directly extract indium from removed copper solution by D2EHPA,and cancel the stage of removing iron in the traditional process because of using iron and part of zinc in the In-Zn concentrates for direct preparing high quality Mn-Zn soft magnetic ferrites.The technologies in the processes,such as leaching the neutral leached residues with high concentrated acid at high temperature,reduction ferric and removing copper,and extracting indium,were investigated.The results show that total recovery ratio of indium is increased from less than 70% in the traditional process to more than 95%.This process has the advantages of largely simplifying the procedure of indium extraction,zero draining off of iron residue and zero emitting of SO2.So this is a clean production process.

Dynamic analysis of heat extraction rate by supercritical carbon dioxide in fractured rock mass based on a thermal-hydraulic-mechanics coupled model

Heat production from geothermal reservoirs is a typical heat transfer process involving a cold working fluid contacting a hot rock formation.Compared to the thermal-physical characteristics of water,supercritical CO_(2)(scCO_(2))has a higher heat storage capacity over a wide temperature-pressure range and may be favored as a heat transfer fluid.Singularly characteristic of scCO_(2)-based heat extraction is that the hydraulic-thermal properties of the scCO_(2) vary dramatically and dynamically with the spatial pressure gradient during unsteady-state flow along fracture.This highly nonlinear behavior presents a challenge in the accurate estimation of heat extraction efficiency in scCO_(2)-based EGS.In this paper,a thermal-h ydraulic-mechanical(THM)coupled model is developed by considering deformation of the fractured reservoir,non-Darcy flow and the varying thermal-physical properties of scCO_(2).The proposed model is validated by matching the modeling temperature distribution with published data.The results show that during continuous injection of scCO_(2),the fracture first widens and then narrows,ultimately reopening over the long term.The sequential fracture deformation behaviors are in response to the combined impacts of mechanical compression and thermally-induced deformation.By controlling the injection parameters of the scCO_(2),it is found that the heat extraction rate is positively correlated to its pore pressure or mass flow rate.The heat extraction rate can be significantly enhanced,when the inlet temperature of scCO_(2) is below its critical temperature.As a result,the heat increment recovered per unit mass of scCO_(2) decreases as the hot rock is gradually cooled.Meanwhile,the heat increment recovered per unit mass of scCO_(2) decreases by increasing the inlet temperature of scCO_(2) or its mass flow rate,but increases as the outlet pressure rises.Furthermore,multi-linear regression indicates that controlling the inlet temperature of the scCO_(2) can significantly improve the thermodynamic efficiency of heat extraction.

In Vitro Antioxidant Activity of Hot Water Extracts from 7 Different Sources of Ganoderma Lucidum

[Objectives] To study the in vitro antioxidant activity of hot water extracts from 7 different sources of Ganoderma lucidum mushroom.[Methods] The in vitro antioxidant activity of hot water extracts from 7 different sources of G. lucidum was studied from total reducing capacity,scavenging of hydroxyl free radical( ·OH),superoxide anion( O_2^(2-)·),and DPPH free radical.[Results]Under the same concentration,hot water extracts wild G. lucidum in Maoer Mountain showed the strongest reducing capacity with the absorbency being 2. 48,the highest scavenging capacity of hydroxyl free radical( · OH) with the scavenging rate being 99. 46%,and the strongest scavenging ability of DPPH free radical with its scavenging rate being 96. 62%. The ability of scavenging superoxide anion free radical( O_2^(2-)·) ranked the third.[Conclusions]The hot water extracts from Maoer Mountain wild G. lucidum showed the highest antioxidant ability in three aspects,indicating that Maoer Mountain wild G. lucidum has high development potential.

Changes in Soil Hot-Water Extractable C,N and P Fractions During Vegetative Restoration in Zhifanggou Watershed on the Loess Plateau

The study was conducted in Zhifanggou Watershed,Shaanxi Province,China,to evaluate the effect of different vegetation types on hot-water extractable C,N and P fractions,with the aim to determine whether hot-water extractable fractions could be used as indicators of soil quality change in Loess Plateau.The six vegetation types established in 1975 were（i） Robinia pseudoacacia L.,（ii） Caragana korshinkii Kom.,（iii） Pinus tabulaeformis Carr.,（iv） P.tabulaeformis-Amorpha fruticosa L.,（v） R.pseudoacacia-A.fruticosa,and（vi） grassland.A cropped hillslope plot and a Platycladus orientalis L.native forest plot were used as references.The results indicated that the conversion of native forest to cropland resulted in a significant decline in the hot-water extractable C,N and P fractions.Hot-water extractable C,N,and P increased when cultivated land was revegetated,but after 30 years the amount of hot-water extractable C,N,and P in revegetated fields was still much lower compared to native forest.Hot-water extractable fractions increased more under mixed-forest than under pure-forest stands.Furthermore,there was a significant correlation between the hot-water extractable fractions and soil chemical and microbiological properties.The results showed that hot-water extractable fractions could be used as indicators of soil quality change on the Loess Plateau.

Artificial neural network techniques to predict the moisture ratio content during hot air drying and vacuum drying of Radix isatidis extract

Background:To predict the moisture ratio of Radix isatidis extract during drying.Methods:Artificial neural networks were designed using the MATLAB neural network toolbox to produce a moisture ratio prediction model of Radix isatidis extract during hot air drying and vacuum drying,where regression values and mean squared error were used as evaluation indexes to optimize the number of hidden layer nodes and determine the topological structure of artificial neural networks model.In addition,the drying curves for the different drying parameters were analyzed.Results:The optimal topological structure of the moisture ratio prediction model for hot air drying and vacuum drying of Radix isatidis extract were“4-9-1”and“5-9-1”respectively,and the regression values between the predicted value and the experimental value is close to 1.This indicates that it has a high prediction accuracy.The moisture ratio gradually decreases with an increase in the drying time,reducing the loading,initial moisture content,increasing the temperature,and pressure can shorten the drying time and improve the drying efficiency.Conclusion:Artificial neural networks technology has the advantages of rapid and accurate prediction,and can provide a theoretical basis and technical support for online prediction during the drying process of the extract.

The Influence of Drying Temperature and Extraction Methods on a-Mangostin in Mangosteen Pericarp

The effects of drying temperature and extraction methods on α-mangostin content in mangosteen pericarp （Garcinia mangostana L.） powder were investigated. In the first part of experiment suitable drying temperature for retention α-mangostin content was determined. Three levels of drying temperatures （55, 65 and 75 ℃） were used in this study. The drying rates were increased with drying temperature. Room temperature extraction method was performed to investigate the effect of drying temperature on retention α-mangostin content in mangosteen pericarp. The α-mangostin content extracted at three different drying temperatures （55, 65 and 75 ℃） was 35.98 ± 0.49%, 40.32 ± 0.24%, and 37.79±0.34% w/w, respectively. The results showed that the suitable temperature for drying mangosteen pericarp was 65 ℃ that gave the highest of α-mangostin content. The second part of experiment was the comparison between extraction methods, such as shaking water bath extraction （SWE）, soxhlet extraction （SE） and microwave-assisted extraction （MAE）. The results show that MAE gave the highest extraction rate and α-mangostin content as compare to SWE and SE. The α-mangostin content extraction from SWE, SE and MAE are 45.83 ± 0.02, 34.82± 0.17 and 49.79 ± 0.15% w/w of crude extract, respectively.

Effects of hot-water extract of <i>Paecilomyces hepiali</i>on hypertension parameters in Spontaneously Hypertensive Rats

In this study, effects of hot water extract of Paecilomyces hepiali mycelia on hypertension parameters in spontaneously hypertensive rats (SHR) were investigated. The tested parameters included blood pressure, blood and urine biochemical composition, renin and angiotensin II levels in the blood. Prior to these tests, the extract was examined for toxicity. The fungus was cultivated in a solid medium composed of 40 g brown rice, 0.32 g glucose, 0.65 g sucrose, 2 g peptone and 65 ml corn steep liquor. No abnormality or harmful effects were observed in the toxicity test. Administration of a continuous-dose, once daily, to SHR for 27 weeks (from 13 weeks of age) decreased the systolic blood pressure (SBP) significantly. Levels of blood urea nitrogen, β-lipoprotein lipid peroxides and low density lipoprotein were significantly lower in the treated groups when compared to the control group. Urinary protein was significantly reduced in the middle and high dose groups. In comparison with the control group (0 mg/kg/10ml/day), significantly higher values were obtained for total cholesterol in groups that were given middle (170 mg/kg/10ml/day) and high (250 mg/kg/10ml/day) dosages. In all dosages (low, middle and high) the values for triglyceride were significantly higher than value found in the control group. In terms of angiotensin II levels, the value in the control group was markedly higher than values in the other groups. The results suggest that oral administration of hot water extract of P. hepiali mycelia has ability to control hypertension in rats.

干热岩压裂储层布井方式优选数值模拟

增强型地热系统(EGS)是从干热岩储层中提取热能的重要手段,而布井方式是影响其采热效果的关键因素,目前开展的布井方式研究较少考虑压裂储层开采模型的影响。建立了干热岩压裂储层采热的数值模型,通过不同位置的基质岩体温度下降幅度、热提取率、采出温度和采热功率对比分析了4种不同的布井方式对EGS采热性能的影响。结果表明:相较于直井,水平井的流体热交换的面积更大,能充分开发裂缝间的热量。在生产30 a时,考虑水力压裂裂缝连通的情况下,水平井一注两采模型的采热效率最高,其在垂直于井方向上温度波及范围约690 m,基质岩体平均温度下降38.09 K,热提取率为24.42%,采热功率为3.5 MW。研究成果为提高地热系统产热量、实现干热岩高效可持续开发提供了理论参考。

传统服饰纹样设计转化研究的演进脉络与热点主题

文章以探寻中国传统服饰纹样设计转化研究规律为出发点,选取近20年CNKI中的425篇传统服饰纹样设计转化研究的期刊文献,基于文献计量的实证分析,从知识生产脉络、知识生产主体、知识基础、关键词共现和时间线等维度,对传统服饰纹样设计转化研究进行梳理分析。研究发现,20年来该领域发文量增长快速,知识生产主体之间尚未形成稳定的合作网络;设计转化中传统服饰纹样吉祥文化的物化表达、传统服饰纹样提取的方法革新、多学科融合驱动传统服饰纹样设计转化创新发展是研究的热点;传统服饰纹样设计转化演化脉络可分为三个阶段,强调用户体验的交互设计、基于用户情感的服务设计、设计转化中的文化自信、共性到个性的心理需求转变、“实用性”转向“精神性”是该领域的研究趋势。

微波处理对刺槐豆胶多糖结构特征的影响

采用微波辅助法(microwave-assisted extraction,MAE)和热水浸提法(hot water extraction,HWE)处理刺槐豆胶,并对得到的刺槐豆胶多糖(locust bean gum polysaccharide,LBGP)进行分子量及分子量分布、糖链构象、单糖组成、糖苷键类型等一系列表征进行分析。通过比较发现,MAE-LBGP的分子量(2.744〜3.777×10^(6) g/mol)显著高于HWE-LBGP(1.222〜1.593×10^(6) g/mol),且具有更宽的分子量分布,不均一性的增强使得糖链呈现出更加多样化及更为紧密的构象特征,而HWE-LBGP的构象则表现得相对单一和松散。经由两种提取方式得到的LBGP具有相同的单糖组成种类(甘露糖和半乳糖)和糖苷键类型(1→4与1→6位连接键)。以上结果归因于在微波效应的作用下,溶剂的极化作用增强,提取能力增加,并通过增强溶剂的传质能力,获得了高分子量和更宽分布的多糖所致。本研究为微波技术在多糖提取应用方面提供了支持和帮助。

凉粉草多糖提取和分级及抗氧化性能

文中采用热碱提取法结合超声技术制备了凉粉草多糖(MCP),然后进一步根据相似相溶的原理对凉粉草多糖进行分级,成功获得了分级多糖MCP-1和MCP-2,并通过单因素实验研究了超声时间和提取次数对凉粉草多糖提取率的影响。结果表明,凉粉草多糖的最佳提取条件为在超声功率400W时超声60min,碱提取4次,在此条件下,多糖产率为44.02%±0.06%。紫外和红外光谱测试表明MCP是一种含糖醛酸的粗多糖,凝胶渗透色谱测试其重均分子量(Mw)为4.991×105。而体外抗氧化实验表明,与MCP相比,MCP-1对羟基自由基的清除能力较强,MCP-2对超氧阴离子自由基的清除能力较强,在生物医药领域具有广阔的应用前景。

猫爪草固态发酵工艺优化及抗氧化活性研究

该试验以猫爪草(Ranunculus ternatus Thunb.)醇溶性浸出物的得率为评价指标,采用单因素试验及响应面法优化猫爪草固态发酵工艺,并分析发酵前后提取物主要成分含量和抗氧化能力的变化。结果表明,猫爪草粉末固态发酵最佳工艺为球毛壳菌(Chaetomium globosum)∶镰刀菌(Fusarium equiseti)=1∶1(V/V),发酵时间5 d,猫爪草粉末过筛目号40目,水与猫爪草粉末液料比0.7∶1(mL∶g),发酵温度30℃,接种量5%。在此条件下发酵猫爪草醇溶性浸出物得率为46.12%,且发酵后猫爪草水溶性浸出物、多糖含量较发酵前均有所下降,醇溶性浸出物、黄酮、皂苷、多酚、有机酸和总氨基酸的含量较发酵前均有所提高。发酵后醇溶性浸出物清除1,1-二苯基-2-三硝基苯肼(DPPH)、2,2'-联氮-二-(3-乙基-苯并噻唑-6-磺酸)二铵盐(ABTS)、羟基自由基(·OH)的半抑制浓度(IC50)分别为4.88 mg/mL、3.29 mg/mL、7.36 mg/mL,较发酵前也均有所下降,表明猫爪草醇提取物发酵后的抗氧化能力有所上升,该研究为后续猫爪草发酵工艺的优化和发酵产品的开发提供理论支持。

青海共和盆地干热岩注采大尺度物理模拟实验

基于自主研制的真三轴多物理场原位注采大型物理模拟实验系统,开展了青海共和干热岩多井长期注采物理模拟实验。通过多井连通性实验获得了岩样内部天然裂缝系统的空间分布特征以及各裂缝与井筒的连通情况,在此基础上选择注入井和生产井,开展了一注两采和一注一采实验,系统分析了生产井的开采流量、开采温度、采热速率和流体采收率随持续注采的变化规律。结果表明:在热冲击、注入压力联合作用下,裂缝导流能力增强,生产井开采温度表现为下降趋势,且流量越大下降越快;当裂缝局部闭合区域逐渐激活,产生新的换热面积,开采温度升高或下降速率降低;采热速率主要由开采流量、注入和采出流体的温度差控制,当滤失通道导流能力增强,生产井流体采收率快速下降;优势通道和换热流体滤失对采热性能的影响机制有所区别,前者限制换热面积,后者影响采出流体流量,二者都是影响干热岩长期高效开发的重要因素。

饲用桑叶多糖提取工艺优化及其体外抗菌活性研究

试验以饲用桑叶为原料,采用热水浸提法提取多糖。以提高桑叶中多糖提取率为优化目标,采用单因素试验分别研究液料比、提取温度和提取时间对多糖提取率的影响,利用正交分析法优化桑叶多糖提取工艺参数组合,并利用牛津杯法检测桑叶多糖的体外抑菌活性。结果显示,各因素对桑叶多糖提取率的影响排序为提取温度>液料比>提取时间,最优生产工艺参数组合为液料比30 L/g、提取温度90℃、提取时间3 h。在最优工艺条件下,桑叶多糖提取率为6.69%。桑叶多糖对金黄色葡萄球菌和大肠杆菌具有明显的抑制作用,抑菌圈直径分别为9.22、11.74 mm,最低抑菌浓度均为2.0 g/L。研究表明,热水浸提法提取的桑叶多糖可作为功能性饲料添加剂应用于动物养殖。

一套复杂的倒装热流道注塑模具设计

针对一款碎纸机上壳塑件,为解决塑件表面进胶出现浇口痕的问题,特别设计了一副复杂倒装结构的后模进胶方式的热流道模具。通过设计机械拉勾的方式完成顶出动作。鉴于塑件四周倒扣和内部骨位多的结构特性,后模侧向设计了四边滑块拼接抽芯方式脱模;后模芯设计了多处镶件结构,方便加工、防止困气、提高成型效率及品质。量产过程中,模具各机构运行平稳,塑件品质优秀,符合设计要求。

连翘多糖提取工艺优化及抗氧化和抑菌活性研究

以连翘果实为原料,采用超声波辅助水提醇沉法提取连翘粗多糖,以连翘粗多糖提取率为考察指标,在单因素试验的基础上,采用正交试验对连翘粗多糖提取工艺进行优化,进而采用DPPH法和ABTS法考察连翘多糖体外抗氧化活性,抑菌圈法考察连翘多糖对大肠埃希菌等食物腐败菌的抑菌活性。结果表明,连翘果实多糖的最佳提取工艺为:料液比1:20(g:mL),提取温度70℃,超声功率70 W,提取时间50 min。在此条件下,连翘果实多糖提取率为1.98%。连翘粗多糖对金黄色葡萄球菌和大肠埃希菌均有良好的生长抑制作用,且对金黄色葡萄球菌的抑制作用优于大肠埃希菌。当连翘粗多糖质量浓度为2.5 mg/mL时,大肠埃希菌的抑菌圈平均直径为10.46 mm,金黄色葡萄球菌抑菌圈平均直径为11.73 mm。连翘多糖对DPPH·和ABTS·有较好的清除能力,并呈现良好的质量浓度-效应关系。连翘多糖不但对食品腐败菌有一定的抑菌活性,还具有良好的体外抗氧化活性。可见,连翘粗多糖具有开发成食品防腐保鲜剂的潜能。