Effect of Pore Packing Defects in 2-D Ordered Mesoporous Carbons on Ionic Transport

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粉末粒径对MIM小模数齿轮质量性能的影响研究

粉末粒径对MIM小模数齿轮质量性能的影响研究

2023年第47卷第12期Journal of Mechanical Transmission粉末粒径对MIM小模数齿轮质量性能的影响研究钟志丞1,3潘春荣1林玲2任继华2,3(1 江西理工大学机电工程学院,江西赣州341000)(2 赣南科技学院智能制造与汽车工程学院,江西赣州341000)(3 江苏精研科技股份有限公司,江苏常州213023)摘要采用金属粉末注射成形(Metal powder Injection Molding,MIM)工艺研制小模数齿轮,为改善齿轮烧结件的质量性能,采用不同粒径的粉末进行制备;采用熔体流速测定仪、孔隙率测定软件、2.5次元影像测量仪和显微维氏硬度计等分析齿轮的烧结性能,研究了粉末粒径对齿轮表面质量、孔隙率和收缩率的影响机制。

结果表明,5.0 µm粉末制备的齿轮,粉末流动性能差,烧结后粉末浓度分布不均匀,表面存在黑线,并且尺寸收缩不均匀,影响尺寸精度;9.0 µm粉末制备的齿轮,烧结颈形成能力差,扩散机制进程滞缓,导致烧结后孔隙率高,孔隙尺寸大;采用7.0 µm粉末制备齿轮时,齿轮的质量性能最好,齿轮不存在表面缺陷,孔隙率降至2.9 %,维氏硬度值达到355,收缩率均匀性高,尺寸精度高,所检项目精度等级在GB 2363—1990标准下均高于7级。

关键词金属粉末注射成形粉末粒径表面质量孔隙率收缩率Research on Effect of Powder Particle Size on Quality Performance of MIMSmall Module GearsZhong Zhicheng1,3Pan Chunrong1Lin Ling2 Ren Jihua2,3(1 School of Mechanical and Electrical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China)(2 School of Intelligent Manufacturing and Automotive Engineering, Gannan University of Science and Technology, Ganzhou 341000, China)(3 Jiangsu Gian Technology Co., Ltd., Changzhou 213023, China)Abstract When using the process of metal powder injection molding (MIM) to prepare small module gears, in order to improve the quality and performance of the sintered parts of the gear, powder with different particle sizes is prepared. The sintering performance of the gear is analyzed by the melt flow meter, the porosity measurement software, the 2.5-dimensional image measuring instrument and the micro-Vickers hardness tester. The influence mechanism of particle sizes on the surface quality, porosity and shrinkage of gears is studied. The results show that due to the poor powder flow performance of the gear made of 5.0 µm powder, the powder concentration distribution is not uniform after sintering, there are black lines on the surface, and the dimensional shrinkage is not uniform, which affect the dimensional accuracy. Due to the poor sintering neck formation ability and slow diffusion process of the gear made of 9.0 µm powder, the porosity after sintering is high and the pore size is large. When the 7.0 µm powder is used to prepare the gear, the quality performance of the gear is the best. The gear has no surface defects, the porosity is reduced to 2.9%, the Vickers hardness value reaches 355, the shrinkage uniformity is high, the dimensional accuracy is high, and the accuracy of thetested items are better than class 7 according to the national standard GB 2363—1990.Key words Metal powder injection molding(MIM)Powder particle size Surface quality Porosity Shrinkage0 引言作为精密减速器最基本的传动部件,小模数齿轮广泛应用于航空航天、机械传动等领域[1],其质量优劣直接影响减速器的传动性能。

蓄电池技术手册中英文版

蓄电池技术手册中英文版

● Portable TV, pickup camera, radio and tape recorder.●电动工具、割草机、吸尘器。

●Electric tool, field mower. Vacuum cleaner.●照相机、新闻摄影设备。

●Camera, news photography equipment.●便携式个人计算机、语言处理器、终端。

●Portable personal computer, language processor, terminal.●野外测试设备、医疗仪器设备。

●Outdoor testing equipment, medical instrument equipment.●移动电话机、对讲机。

●Mobile phone, walkie-talkie.●矿灯、割胶灯、应急灯、铁路信号灯。

●Lamp, tapping lamp, emergency light, railway signal light.●电动玩具、电动轮椅。

●Electric toy, electric wheel chair.3 电池结构Structure of the battery图1.蓄电池结构(12V系列) Fig.1 structrue of the storage battery (12V series)图2.蓄电池结构(2V系列) Fig.2 structrue of the storage battery (2V series)表1 SUPER FM GFM 系列蓄电池构件与功能Table.1 SUPER FM GFM series storage battery component and its function部件结构材料功能battery to be 13.5V. While float charge saturation state reaches, float charge current shall be generally 2-4mA for each AH, whose charging feature shown as Fig.5.浮充电压应根据温度变化进行调整,其校正系数K为-3mV/℃即Float charge voltage must be regulated in accordance with variation of temperature, herein ,calibrating coefficient K is -3mv/℃Vt=V25+K(t-25)具体选择可按图6进行。

镍柱纯化蛋白说明书

镍柱纯化蛋白说明书

Instruction ManualProBond TM Purification SystemFor purification of polyhistidine-containing recombinant proteinsCatalog nos. K850-01, K851-01, K852-01, K853-01, K854-01,R801-01, R801-15Version K2 September200425-0006iiTable of ContentsKit Contents and Storage (iv)Accessory Products (vi)Introduction (1)Overview (1)Methods (2)Preparing Cell Lysates (2)Purification Procedure—Native Conditions (7)Purification Procedure—Denaturing Conditions (11)Purification Procedure—Hybrid Conditions (13)Troubleshooting (15)Appendix (17)Additional Protocols (17)Recipes (18)Frequently Asked Questions (21)References (22)Technical Service (23)iiiKit Contents and StorageTypes of Products This manual is supplied with the following products:Product CatalogNo.ProBond™ Purification System K850-01ProBond™ Purification System with Antibodywith Anti-Xpress™ Antibody K851-01with Anti-myc-HRP Antibody K852-01with Anti-His(C-term)-HRP Antibody K853-01with Anti-V5-HRP Antibody K854-01ProBond™ Nickel-Chelating Resin (50 ml) R801-01ProBond™ Nickel Chelating Resin (150 ml) R801-15ProBond™Purification System Components The ProBond™ Purification System includes enough resin, reagents, and columns for six purifications. The components are listed below. See next page for resin specifications.Component Composition Quantity ProBond™ Resin 50% slurry in 20% ethanol 12 ml5X NativePurification Buffer250 mM NaH2PO4, pH 8.02.5 M NaCl1 × 125 ml bottleGuanidinium LysisBuffer6 M Guanidine HCl20 mM sodium phosphate, pH 7.8500 mM NaCl1 × 60 ml bottleDenaturingBinding Buffer8 M Urea20 mM sodium phosphate, pH 7.8500 mM NaCl2 × 125 ml bottlesDenaturing WashBuffer8 M Urea20 mM sodium phosphate, pH 6.0500 mM NaCl2 × 125 ml bottlesDenaturing ElutionBuffer8 M Urea20 mM NaH2PO4, pH 4.0500 mM NaCl1 × 60 ml bottleImidazole 3 M Imidazole,20 mM sodium phosphate, pH 6.0500 mM NaCl1 × 8 ml bottlePurificationColumns10 ml columns 6Continued on next pageivKit Contents and Storage, ContinuedProBond™Purification System with Antibody The ProBond™ Purification System with Antibody includes resin, reagents, and columns as described for the ProBond™ Purification System (previous page) and 50 µl of the appropriate purified mouse monoclonal antibody. Sufficient reagents are included to perform six purifications and 25 Western blots with the antibody.For more details on the antibody specificity, subclass, and protocols for using the antibody, refer to the antibody manual supplied with the system.Storage Store ProBond™ resin at +4°C. Store buffer and columns at room temperature.Store the antibody at 4°C. Avoid repeated freezing and thawing of theantibody as it may result in loss of activity.The product is guaranteed for 6 months when stored properly.All native purification buffers are prepared from the 5X Native PurificationBuffer and the 3 M Imidazole, as described on page 7.The Denaturing Wash Buffer pH 5.3 is prepared from the Denaturing WashBuffer (pH 6.0), as described on page 11.Resin and ColumnSpecificationsProBond™ resin is precharged with Ni2+ ions and appears blue in color. It isprovided as a 50% slurry in 20% ethanol.ProBond™ resin and purification columns have the following specifications:• Binding capacity of ProBond™ resin: 1–5 mg of protein per ml of resin• Average bead size: 45–165 microns• Pore size of purification columns: 30–35 microns• Recommended flow rate: 0.5 ml/min• Maximum flow rate: 2 ml/min• Maximum linear flow rate: 700 cm/h• Column material: Polypropylene• pH stability (long term): pH 3–13• pH stability (short term): pH 2–14ProductQualificationThe ProBond™ Purification System is qualified by purifying 2 mg of myoglobinprotein on a column and performing a Bradford assay. Protein recovery mustbe 75% or higher.vAccessory ProductsAdditionalProductsThe following products are also available for order from Invitrogen:Product QuantityCatalogNo.ProBond™ Nickel-Chelating Resin 50 ml150 mlR801-01R801-15Polypropylene columns(empty)50 R640-50Ni-NTA Agarose 10 ml25 ml R901-01 R901-15Ni-NTA Purification System 6 purifications K950-01 Ni-NTA Purification Systemwith Antibodywith Anti-Xpress™ Antibody with Anti-myc-HRP Antibody with Anti-His(C-term)-HRP Antibodywith Anti-V5-HRP Antibody 1 kit1 kit1 kit1 kitK951-01K952-01K953-01K954-01Anti-myc Antibody 50 µl R950-25 Anti-V5 Antibody 50 µl R960-25 Anti-Xpress™ Antibody 50 µl R910-25 Anti-His(C-term) Antibody 50 µl R930-25 InVision™ His-tag In-gel Stain 500 ml LC6030 InVision™ His-tag In-gelStaining Kit1 kit LC6033Pre-Cast Gels and Pre-made Buffers A large variety of pre-cast gels for SDS-PAGE and pre-made buffers for your convenience are available from Invitrogen. For details, visit our web site at or contact Technical Service (page 23).viIntroductionOverviewIntroduction The ProBond™ Purification System is designed for purification of 6xHis-tagged recombinant proteins expressed in bacteria, insect, and mammalian cells. Thesystem is designed around the high affinity and selectivity of ProBond™Nickel-Chelating Resin for recombinant fusion proteins containing six tandemhistidine residues.The ProBond™ Purification System is a complete system that includespurification buffers and resin for purifying proteins under native, denaturing,or hybrid conditions. The resulting proteins are ready for use in many targetapplications.This manual is designed to provide generic protocols that can be adapted foryour particular proteins. The optimal purification parameters will vary witheach protein being purified.ProBond™ Nickel-Chelating Resin ProBond™ Nickel-Chelating Resin is used for purification of recombinant proteins expressed in bacteria, insect, and mammalian cells from any 6xHis-tagged vector. ProBond™ Nickel-Chelating Resin exhibits high affinity and selectivity for 6xHis-tagged recombinant fusion proteins.Proteins can be purified under native, denaturing, or hybrid conditions using the ProBond™ Nickel-Chelating Resin. Proteins bound to the resin are eluted with low pH buffer or by competition with imidazole or histidine. The resulting proteins are ready for use in target applications.Binding Characteristics ProBond™ Nickel-Chelating Resin uses the chelating ligand iminodiacetic acid (IDA) in a highly cross-linked agarose matrix. IDA binds Ni2+ ions by three coordination sites.The protocols provided in this manual are generic, and may not result in 100%pure protein. These protocols should be optimized based on the bindingcharacteristics of your particular proteins.Native VersusDenaturingConditionsThe decision to purify your 6xHis-tagged fusion proteins under native ordenaturing conditions depends on the solubility of the protein and the need toretain biological activity for downstream applications.• Use native conditions if your protein is soluble (in the supernatant afterlysis) and you want to preserve protein activity.• Use denaturing conditions if the protein is insoluble (in the pellet afterlysis) or if your downstream application does not depend on proteinactivity.• Use hybrid protocol if your protein is insoluble but you want to preserveprotein activity. Using this protocol, you prepare the lysate and columnsunder denaturing conditions and then use native buffers during the washand elution steps to refold the protein. Note that this protocol may notrestore activity for all proteins. See page 14.1MethodsPreparing Cell LysatesIntroduction Instructions for preparing lysates from bacteria, insect, and mammalian cellsusing native or denaturing conditions are described below.Materials Needed You will need the following items:• Native Binding Buffer (recipe is on page 8) for preparing lysates undernative conditions• Sonicator• 10 µg/ml RNase and 5 µg/ml DNase I (optional)• Guanidinium Lysis Buffer (supplied with the system) for preparing lysatesunder denaturing conditions• 18-gauge needle• Centrifuge• Sterile, distilled water• SDS-PAGE sample buffer• Lysozyme for preparing bacterial cell lysates• Bestatin or Leupeptin, for preparing mammalian cell lysatesProcessing Higher Amount of Starting Material Instructions for preparing lysates from specific amount of starting material (bacteria, insect, and mammalian cells) and purification with 2 ml resin under native or denaturing conditions are described in this manual.If you wish to purify your protein of interest from higher amounts of starting material, you may need to optimize the lysis protocol and purification conditions (amount of resin used for binding). The optimization depends on the expected yield of your protein and amount of resin to use for purification. Perform a pilot experiment to optimize the purification conditions and then based on the pilot experiment results, scale-up accordingly.Continued on next page2Preparing Bacterial Cell Lysate—Native Conditions Follow the procedure below to prepare bacterial cell lysate under native conditions. Scale up or down as necessary.1. Harvest cells from a 50 ml culture by centrifugation (e.g., 5000 rpm for5 minutes in a Sorvall SS-34 rotor). Resuspend the cells in 8 ml NativeBinding Buffer (recipe on page 8).2. Add 8 mg lysozyme and incubate on ice for 30 minutes.3. Using a sonicator equipped with a microtip, sonicate the solution on iceusing six 10-second bursts at high intensity with a 10-second coolingperiod between each burst.Alternatively, sonicate the solution on ice using two or three 10-secondbursts at medium intensity, then flash freeze the lysate in liquid nitrogen or a methanol dry ice slurry. Quickly thaw the lysate at 37°C andperform two more rapid sonicate-freeze-thaw cycles.4. Optional: If the lysate is very viscous, add RNase A (10 µg/ml) andDNase I (5 µg/ml) and incubate on ice for 10–15 minutes. Alternatively,draw the lysate through a 18-gauge syringe needle several times.5. Centrifuge the lysate at 3,000 ×g for 15 minutes to pellet the cellulardebris. Transfer the supernatant to a fresh tube.Note: Some 6xHis-tagged protein may remain insoluble in the pellet, and can be recovered by preparing a denatured lysate (page 4) followed bythe denaturing purification protocol (page 12). To recover this insolubleprotein while preserving its biological activity, you can prepare thedenatured lysate and then follow the hybrid protocol on page 14. Notethat the hybrid protocol may not restore activity in all cases, and should be tested with your particular protein.6. Remove 5 µl of the lysate for SDS-PAGE analysis. Store the remaininglysate on ice or freeze at -20°C. When ready to use, proceed to theprotocol on page 7.Continued on next page3Preparing Bacterial Cell Lysate—Denaturing Conditions Follow the procedure below to prepare bacterial cell lysate under denaturing conditions:1. Equilibrate the Guanidinium Lysis Buffer, pH 7.8 (supplied with thesystem or see page 19 for recipe) to 37°C.2. Harvest cells from a 50 ml culture by centrifugation (e.g., 5000 rpm for5 minutes in a Sorvall SS-34 rotor).3. Resuspend the cell pellet in 8 ml Guanidinium Lysis Buffer from Step 1.4. Slowly rock the cells for 5–10 minutes at room temperature to ensurethorough cell lysis.5. Sonicate the cell lysate on ice with three 5-second pulses at high intensity.6. Centrifuge the lysate at 3,000 ×g for 15 minutes to pellet the cellulardebris.Transfer the supernatant to a fresh tube.7. Remove 5 µl of the lysate for SDS-PAGE analysis. Store the remaininglysate on ice or at -20°C. When ready to use, proceed to the denaturingprotocol on page 11 or hybrid protocol on page 13.Note: To perform SDS-PAGE with samples in Guanidinium Lysis Buffer, you need to dilute the samples, dialyze the samples, or perform TCAprecipitation prior to SDS-PAGE to prevent the precipitation of SDS.Harvesting Insect Cells For detailed protocols dealing with insect cell expression, consult the manual for your particular system. The following lysate protocols are for baculovirus-infected cells and are intended to be highly generic. They should be optimized for your cell lines.For baculovirus-infected insect cells, when the time point of maximal expression has been determined, large scale protein expression can be carried out. Generally, the large-scale expression is performed in 1 liter flasks seeded with cells at a density of 2 × 106 cells/ml in a total volume of 500 ml and infected with high titer viral stock at an MOI of 10 pfu/cell. At the point of maximal expression, harvest cells in 50 ml aliquots. Pellet the cells by centrifugation and store at -70°C until needed. Proceed to preparing cell lysates using native or denaturing conditions as described on the next page.Continued on next page4Preparing Insect Cell Lysate—Native Condition 1. Prepare 8 ml Native Binding Buffer (recipe on page 8) containingLeupeptin (a protease inhibitor) at a concentration of 0.5 µg/ml.2. After harvesting the cells (previous page), resuspend the cell pellet in8 ml Native Binding Buffer containing 0.5 µg/ml Leupeptin.3. Lyse the cells by two freeze-thaw cycles using a liquid nitrogen or dryice/ethanol bath and a 42°C water bath.4. Shear DNA by passing the preparation through an 18-gauge needle fourtimes.5. Centrifuge the lysate at 3,000 ×g for 15 minutes to pellet the cellulardebris.Transfer the supernatant to a fresh tube.6. Remove 5 µl of the lysate for SDS-PAGE analysis. Store remaining lysateon ice or freeze at -20°C. When ready to use, proceed to the protocol on page 7.Preparing Insect Cell Lysate—Denaturing Condition 1. After harvesting insect cells (previous page), resuspend the cell pellet in8 ml Guanidinium Lysis Buffer (supplied with the system or see page 19for recipe).2. Pass the preparation through an 18-gauge needle four times.3. Centrifuge the lysate at 3,000 ×g for 15 minutes to pellet the cellulardebris. Transfer the supernatant to a fresh tube.4. Remove 5 µl of the lysate for SDS-PAGE analysis. Store remaining lysateon ice or freeze at -20° C. When ready to use, proceed to the denaturingprotocol on page 11 or hybrid protocol on page 13.Note: To perform SDS-PAGE with samples in Guanidinium Lysis Buffer, you need to dilute the samples, dialyze the samples, or perform TCAprecipitation prior to SDS-PAGE to prevent the precipitation of SDS.Continued on next pagePreparing Mammalian Cell Lysate—Native Conditions For detailed protocols dealing with mammalian expression, consult the manual for your particular system. The following protocols are intended to be highly generic, and should be optimized for your cell lines.To produce recombinant protein, you need between 5 x 106and 1 x 107 cells. Seed cells and grow in the appropriate medium until they are 80–90% confluent. Harvest cells by trypsinization. You can freeze the cell pellet in liquid nitrogen and store at -70°C until use.1. Resuspend the cell pellet in 8 ml of Native Binding Buffer (page 8). Theaddition of protease inhibitors such as bestatin and leupeptin may benecessary depending on the cell line and expressed protein.2. Lyse the cells by two freeze-thaw cycles using a liquid nitrogen or dryice/ethanol bath and a 42°C water bath.3. Shear the DNA by passing the preparation through an 18-gauge needlefour times.4. Centrifuge the lysate at 3,000 ×g for 15 minutes to pellet the cellulardebris. Transfer the supernatant to a fresh tube.5. Remove 5 µl of the lysate for SDS-PAGE analysis. Store the remaininglysate on ice or freeze at -20° C. When ready to use, proceed to theprotocol on page 7.Preparing Mammalian Cell Lysates—Denaturing Conditions For detailed protocols dealing with mammalian expression, consult the manual for your particular system. The following protocols are intended to be highly generic, and should be optimized for your cell lines.To produce recombinant protein, you need between 5 x 106and 1 x 107 cells. Seed cells and grow in the appropriate medium until they are 80–90% confluent. Harvest cells by trypsinization. You can freeze the cell pellet in liquid nitrogen and store at -70°C until use.1. Resuspend the cell pellet in 8 ml Guanidinium Lysis Buffer (suppliedwith the system or see page 19 for recipe).2. Shear the DNA by passing the preparation through an 18-gauge needlefour times.3. Centrifuge the lysate at 3,000 ×g for 15 minutes to pellet the cellulardebris. Transfer the supernatant to a fresh tube.4. Remove 5 µl of the lysate for SDS-PAGE analysis. Store the remaininglysate on ice or freeze at -20° C until use. When ready to use, proceed to the denaturing protocol on page 11 or hybrid protocol on page 13.Note: To perform SDS-PAGE with samples in Guanidinium Lysis Buffer, you need to dilute the samples, dialyze the samples, or perform TCAprecipitation prior to SDS-PAGE to prevent the precipitation of SDS.Purification Procedure—Native ConditionsIntroduction In the following procedure, use the prepared Native Binding Buffer, NativeWash Buffer, and Native Elution Buffer, columns, and cell lysate preparedunder native conditions. Be sure to check the pH of your buffers before starting.Buffers for Native Purification All buffers for purification under native conditions are prepared from the5X Native Purification Buffer supplied with the system. Dilute and adjust the pH of the 5X Native Purification Buffer to create 1X Native Purification Buffer (page 8). From this, you can create the following buffers:• Native Binding Buffer• Native Wash Buffer• Native Elution BufferThe recipes described in this section will create sufficient buffers to perform one native purification using one kit-supplied purification column. Scale up accordingly.If you are preparing your own buffers, see page 18 for recipe.Materials Needed You will need the following items:• 5X Native Purification Buffer (supplied with the system or see page 18 forrecipe)• 3 M Imidazole (supplied with the system or see page 18 for recipe)• NaOH• HCl• Sterile distilled water• Prepared ProBond™ columns with native buffers (next page)• Lysate prepared under native conditions (page 2)Imidazole Concentration in Native Buffers Imidazole is included in the Native Wash and Elution Buffers to minimize the binding of untagged, contaminating proteins and increase the purity of the target protein with fewer wash steps. Note that, if your level of contaminating proteins is high, you may add imidazole to the Native Binding Buffer.If your protein does not bind well under these conditions, you can experiment with lowering or eliminating the imidazole in the buffers and increasing the number of wash and elution steps.Continued on next page1X Native Purification Buffer To prepare 100 ml 1X Native Purification Buffer, combine:• 80 ml of sterile distilled water• 20 ml of 5X Native Purification Buffer (supplied with the system or see page 18 for recipe)Mix well and adjust pH to 8.0 with NaOH or HCl.Native Binding Buffer Without ImidazoleUse 30 ml of the 1X Native Purification Buffer (see above for recipe) for use as the Native Binding Buffer (used for column preparation, cell lysis, and binding).With Imidazole (Optional):You can prepare the Native Binding Buffer with imidazole to reduce the binding of contaminating proteins. (Note that some His-tagged proteins may not bind under these conditions.).To prepare 30 ml Native Binding Buffer with 10 mM imidazole, combine: • 30 ml of 1X Native Purification Buffer• 100 µl of 3 M Imidazole, pH 6.0Mix well and adjust pH to 8.0 with NaOH or HCl.Native Wash Buffer To prepare 50 ml Native Wash Buffer with 20 mM imidazole, combine:• 50 ml of 1X Native Purification Buffer• 335 µl of 3 M Imidazole, pH 6.0Mix well and adjust pH to 8.0 with NaOH or HCl.Native Elution Buffer To prepare 15 ml Native Elution Buffer with 250 mM imidazole, combine:• 13.75 ml of 1X Native Purification Buffer• 1.25 ml of 3 M Imidazole, pH 6.0Mix well and adjust pH to 8.0 with NaOH or HCl.Continued on next pageDo not use strong reducing agents such as DTT with ProBond™ columns. DTTreduces the nickel ions in the resin. In addition, do not use strong chelatingagents such as EDTA or EGTA in the loading buffers or wash buffers, as thesewill strip the nickel from the columns.Be sure to check the pH of your buffers before starting.PreparingProBond™ ColumnWhen preparing a column as described below, make sure that the snap-off capat the bottom of the column remains intact. To prepare a column:1. Resuspend the ProBond™ resin in its bottle by inverting and gentlytapping the bottle repeatedly.2. Pipet or pour 2 ml of the resin into a 10-ml Purification Columnsupplied with the kit. Allow the resin to settle completely by gravity(5-10 minutes) or gently pellet it by low-speed centrifugation (1 minuteat 800 ×g). Gently aspirate the supernatant.3. Add 6 ml of sterile, distilled water and resuspend the resin byalternately inverting and gently tapping the column.4. Allow the resin to settle using gravity or centrifugation as described inStep 2, and gently aspirate the supernatant.5. For purification under Native Conditions, add 6 ml Native BindingBuffer (recipe on page 8).6. Resuspend the resin by alternately inverting and gently tapping thecolumn.7. Allow the resin to settle using gravity or centrifugation as described inStep 2, and gently aspirate the supernatant.8. Repeat Steps 5 through 7.Storing PreparedColumnsTo store a column containing resin, add 0.02% azide or 20% ethanol as apreservative and cap or parafilm the column. Store at room temperature.Continued on next pagePurification Under Native Conditions Using the native buffers, columns and cell lysate, follow the procedure below to purify proteins under native conditions:1. Add 8 ml of lysate prepared under native conditions to a preparedPurification Column (page 9).2. Bind for 30–60 minutes using gentle agitation to keep the resinsuspended in the lysate solution.3. Settle the resin by gravity or low speed centrifugation (800 ×g), andcarefully aspirate the supernatant. Save supernatant at 4°C forSDS-PAGE analysis.4. Wash with 8 ml Native Wash Buffer (page 8). Settle the resin by gravityor low speed centrifugation (800 ×g), and carefully aspirate thesupernatant. Save supernatant at 4°C for SDS-PAGE analysis.5. Repeat Step 4 three more times.6. Clamp the column in a vertical position and snap off the cap on thelower end. Elute the protein with 8–12 ml Native Elution Buffer (seepage 2). Collect 1 ml fractions and analyze with SDS-PAGE.Note: Store the eluted fractions at 4°C. If -20°C storage is required, addglycerol to the fractions. For long term storage, add protease inhibitors to the fractions.If you wish to reuse the resin to purify the same recombinant protein, wash the resin with 0.5 M NaOH for 30 minutes and equilibrate the resin in a suitable binding buffer. If you need to recharge the resin, see page 17.Purification Procedure—Denaturing ConditionsIntroduction Instructions to perform purification using denaturing conditions with prepareddenaturing buffers, columns, and cell lysate are described below.Materials Needed You will need the following items:• Denaturing Binding Buffer (supplied with the system or see page 19 forrecipe)• Denaturing Wash Buffer, pH 6.0 (supplied with the system or see page 19 forrecipe) and Denaturing Wash Buffer, pH 5.3 (see recipe below)• Denaturing Elution Buffer (supplied with the system or see page 20 forrecipe)• Prepared ProBond™ columns with Denaturing buffers (see below)• Lysate prepared under denaturing conditions (page 11)Preparing the Denaturing Wash Buffer pH 5.3 Using a 10 ml aliquot of the kit-supplied Denaturing Wash Buffer (pH 6.0), mix well, and adjust the pH to 5.3 using HCl. Use this for the Denaturing Wash Buffer pH 5.3 in Step 5 next page.Be sure to check the pH of your buffers before starting. Note that thedenaturing buffers containing urea will become more basic over time. PreparingProBond™ ColumnWhen preparing a column as described below, make sure that the snap-off capat the bottom of the column remains intact.If you are reusing the ProBond™ resin, see page 17 for recharging protocol.To prepare a column:1. Resuspend the ProBond™ resin in its bottle by inverting and gentlytapping the bottle repeatedly.2. Pipet or pour 2 ml of the resin into a 10-ml Purification Columnsupplied with the kit. Allow the resin to settle completely by gravity(5-10 minutes) or gently pellet it by low-speed centrifugation (1 minuteat 800 ×g). Gently aspirate the supernatant.3. Add 6 ml of sterile, distilled water and resuspend the resin byalternately inverting and gently tapping the column.4. Allow the resin to settle using gravity or centrifugation as described inStep 2, and gently aspirate the supernatant.5. For purification under Denaturing Conditions, add 6 ml of DenaturingBinding Buffer.6. Resuspend the resin by alternately inverting and gently tapping thecolumn.7. Allow the resin to settle using gravity or centrifugation as described inStep 2, and gently aspirate the supernatant. Repeat Steps 5 through 7.Continued on next pagePurification Procedure—Denaturing Conditions, ContinuedPurification Under Denaturing Conditions Using the denaturing buffers, columns, and cell lysate, follow the procedure below to purify proteins under denaturing conditions:1. Add 8 ml lysate prepared under denaturing conditions to a preparedPurification Column (page 11).2. Bind for 15–30 minutes at room temperature using gentle agitation (e.g.,using a rotating wheel) to keep the resin suspended in the lysatesolution. Settle the resin by gravity or low speed centrifugation (800 ×g), and carefully aspirate the supernatant.3. Wash the column with 4 ml Denaturing Binding Buffer supplied with thekit by resuspending the resin and rocking for two minutes. Settle theresin by gravity or low speed centrifugation (800 ×g), and carefullyaspirate the supernatant. Save supernatant at 4°C for SDS-PAGEanalysis. Repeat this step one more time.4. Wash the column with 4 ml Denaturing Wash Buffer, pH 6.0 supplied inthe kit by resuspending the resin and rocking for two minutes. Settle the resin by gravity or low speed centrifugation (800 ×g), and carefullyaspirate the supernatant. Save supernatant at 4°C for SDS-PAGEanalysis. Repeat this step one more time.5. Wash the column with 4 ml Denaturing Wash Buffer pH 5.3 (see recipeon previous page) by resuspending the resin and rocking for 2 minutes.Settle the resin by gravity or low speed centrifugation (800 ×g), andcarefully aspirate the supernatant. Save supernatant at 4°C for SDS-PAGE analysis. Repeat this step once more for a total of two washes with Denaturing Wash Buffer pH 5.3.6. Clamp the column in a vertical position and snap off the cap on thelower end. Elute the protein by adding 5 ml Denaturing Elution Buffersupplied with the kit. Collect 1 ml fractions and monitor the elution bytaking OD280readings of the fractions. Pool the fractions that contain the peak absorbance and dialyze against 10 mM Tris, pH 8.0, 0.1% Triton X-100 overnight at 4°C to remove the urea. Concentrate the dialyzedmaterial by any standard method (i.e., using 10,000 MW cut-off, low-protein binding centrifugal instruments or vacuum concentrationinstruments).If you wish to reuse the resin to purify the same recombinant protein, wash the resin with 0.5 M NaOH for 30 minutes and equilibrate the resin in a suitable binding buffer. If you need to recharge the resin, see page 17.。

产品过度包装的影响英语作文

产品过度包装的影响英语作文

产品过度包装的影响英语作文英文回答:Environmental Impacts of Excessive Product Packaging.Excessive product packaging has a profound impact onthe environment, exacerbating problems such as pollution, deforestation, and climate change.Pollution: Packaging materials, primarily plastics, contribute significantly to pollution. When not properly disposed of, plastic packaging ends up in landfills, oceans, and waterways, polluting the environment and harming wildlife. The production and disposal of packagingmaterials also release toxic chemicals into the air, water, and soil.Deforestation: The production of paper and cardboard packaging requires large amounts of wood, leading to deforestation. Forests play a crucial role in regulatingthe climate, providing oxygen, and supporting biodiversity. Deforestation also results in soil erosion, habitat loss, and disruption of water cycles.Climate Change: The production and disposal of packaging materials contribute to greenhouse gas emissions. Plastic production relies heavily on fossil fuels, while the production of paper and cardboard requires energy-intensive processes. The transportation of packaged goods also contributes to emissions.Economic Impacts of Excessive Product Packaging.Excessive product packaging also has significant economic consequences:Increased Costs: Excessive packaging adds to the cost of products, as manufacturers must factor in the materials, production, and disposal costs. These costs are ultimately passed on to consumers, leading to higher prices.Waste Management Costs: Improper disposal of packagingmaterials poses a challenge for waste management systems. Discarded packaging takes up valuable landfill space and can clog landfills, increasing disposal costs.Lost Revenue: Excessive packaging can deter consumers from purchasing products. Customers may opt for products with less packaging or choose reusable alternatives, resulting in lost revenue for businesses.Social Impacts of Excessive Product Packaging.Excessive product packaging also affects society in various ways:Consumer Deception: Excessive packaging can be misleading to consumers. It can create the illusion of a larger product, thereby influencing purchasing decisions.Environmental Awareness: Excessive packaging contributes to environmental degradation, which has raised awareness among consumers. Consumers are increasingly demanding products with sustainable packaging or seekingways to reduce their packaging consumption.Health Risks: Some packaging materials, such ascertain types of plastic, contain harmful chemicals that can leach into food or the environment. These chemicals can pose health risks to humans and wildlife.Conclusion:Excessive product packaging has severe environmental, economic, and social impacts. It contributes to pollution, deforestation, and climate change, increases costs, hinders waste management, and misleads consumers. To address these challenges, there is a need for sustainable packaging practices, including reducing packaging materials, using biodegradable or reusable alternatives, and educating consumers about the importance of responsible packaging.中文回答:过度产品包装对环境的影响。

多孔材料的应用研究与发展前景

多孔材料的应用研究与发展前景

Equipment Manufacturing Technology No.2,2014多孔材料是一种新兴材料体系,其最显著的特点,是具有规则排列、大小可调的孔道结构,其独有的机械、吸附、渗透、光电及生物活性等特性,在结构及光电材料、吸附及分离介质、生物医学等领域具有广阔应用前景,自问世以来,备受国际诸多学科领域学者重视,迅速成为跨学科研究的焦点和热点。

1多孔材料的特性1.1机械性能多孔材料制备的零件,能在降低密度的同时,提高强度和刚度等机械性能。

据测算,使用多孔材料制造的飞机,在同等机械性能条件下,净质量将减轻一半。

另外,多孔材料具有较高的冲击韧性,应用于汽车工业,将有效降低交通事故给乘客带来的伤害。

1.2吸附性能不同气体或液体的分子直径及热运动自由度各不相同,因此,可利用同类多孔材料对不同气体或液体吸附能力的差异特性,制备出用于净化气体或液体且可重复使用的高效多孔吸附净化材料。

1.3渗透性能在材料制备过程中,通过控制孔道尺寸、方向、孔型及排列规律等结构特征,结合多孔材料耐热性好,结构稳定性高等固有特性,可制备出多孔分子筛、高温气体分离膜等过滤装置。

1.4波的传播多孔材料中的孔隙,可增加机械波在传播过程中发生反射、折射及衍射的可能性。

因此,通过制备过程中孔道结构的合理设计,可达到较好的阻波效果,应用于隔音、减振及抗爆炸冲击等领域。

1.5光电性能多孔硅材在激光照射下可发出可见光,根据这一特性,被认为是新型光电子元件的理想材料。

同时,多孔材料也被认为是未来混合动力汽车新型燃料电池中电极材料的首选。

1.6生物性能由于多孔材料具备相对密度小、比强度大、比表面积高等结构特点,使其生物活性及生物相容性得到显著提高,性能稳定的仿生多孔材料是未来最理想的生物药剂载体及骨骼替代材料。

2制备方法与技术随着多孔材料应用的推广,涉及领域的增多,使用性能的开发,性能要求不断提高,制备技术也在不断的更新发展。

2.1粉末冶金法粉末冶金技术主要用于制备金属基陶瓷复合材料及不锈钢、镍合金等金属材料,是制备多孔材料的主要方法之一,具有强度高、孔隙分布窄、孔径大小可控等优点。

普罗布考对2型糖尿病肾病大鼠足细胞的保护作用

普罗布考对2型糖尿病肾病大鼠足细胞的保护作用

• 1832 •现代中西医结合杂志Modern Journal of Integrated Traditional Chinese and Western Medicin 普罗布考对2型糖尿病肾病大鼠足细胞的保护作用成丽岚1黄金华2马爱江1齐杉1郑少雄3(1.河北省直属机关第二门诊部,河北石家庄050051 ;.北京市中关村医院,北京100080;.天津医科大学第二医院,天津300211)[摘要] 探讨普罗布考对糖尿病肾病大鼠足细胞的保护作用及相关机制。

将36只雄性S D大鼠随机分为3组,正常组10只给予普通饲料喂养,模型组13只和普罗布考组13只给予高糖高脂饲料喂养。

喂养8周后,模型组和普罗布考组以小剂量链脲佐菌素(S T Z)(15〜2m g k g)腹腔注射诱导2型糖尿病模型。

之后普罗布考组给予普罗布考500 m g/(kg • d)灌胃,正常组和模型组给予0.5%羟曱基纤维素钠灌胃,均1次/d,连续8周,期间模型组和普罗布考组给予高糖高脂饲料喂养,正常组普通饲料喂养。

测定3组大鼠血糖、血脂及氧化应激指标,免疫组化法检测肾组织中Nephrin蛋白表达情况,RT -P C R法检测肾组织中Nephrin、podocin和CD2A Pm R N A表达情况。

模型组和普罗水平均明显低于模型组(尸均<0. 05),但FPG、HbA1c、H0MA -I与模型组比较差异均无统计学意义(尸均〉0. 05)。

模型组血清S0D、GSH - P x含量和肾组织中N ephrin蛋白及Nephrin、p〇docin、C D2A Pm R N A相对表达量均明显低于正常组(尸均<0.05),血清M DA含量明显高于正常组(尸<0. 05);普罗布考组血清S0D、GSH - P x含量和肾组织中N ephrin蛋白及Nephrin、podocin、CD2 AP m R N A相对表达量均明显高于模型组(P均< 0. 05 ),血清M DA含量明显低于模型组(P< 0.05)。

多孔碳电极用于多硫化钠溴储能电池

多孔碳电极用于多硫化钠溴储能电池

多孔碳电极用于多硫化钠!滨储能电池周汉涛1,29张华民19葛善海19刘浩19衣宝廉1(1.中国科学院大连化学物理研究所燃料电池工程中心9辽宁大连11602392.中国科学院研究生院9北京100039)摘要 研究了多硫化钠-溴 PSB 储能电池用多孔碳电极0电极材料为活性炭\导电炭黑\热塑性聚合物粘结剂9电极采用热压成型方法制备0用多孔炭电极作为电池正负极9系统地探讨了电极组成\活性炭颗粒粒径\造孔剂对电池充放电性能的影响0粘结剂量一定时9导电炭黑\活性炭比例存在最优值0大颗粒活性炭有利于保持电极的机械稳定性0加大造孔剂的量9促进了电极内孔的连通性9电池性能提高0活性炭制得的电极具有较高的电化学活性9在80 C \120mA/cm 2放电电流密度时比功率达0.14 W/cm 2 1.19 V 9可见活性炭是一种高性价比的PSB 储能电池电极材料0关键词 活性炭9造孔剂9储能电池9多硫化钠9溴中图分类号:TM 911.18 文献标识码:A 文章编号:1002-087 X (2005)03-0170-05Porous carbon electrodes for sodium polysulfide-bromine redox flowenergy storage cellZHOU Han-tao 1,2, ZHANG Hua-min 1, GE Shan-hai 1, LIU Hao 1, YI Bao-lian 1(1.fuel cell R&D Center a Dalian Institute of Chemical Physics a Chinese Academy of Sciences a Dalian Liaoning 116023a China g2.Graduate School of the Chinese Academy of Sciences,Beijing 100039,China)Porous carbon electrodes for sodium polysulfide/bromine (PSB) energy storage cell were investigated in this paper.The electrodes were prepared by hot isostatic pressing with activated carbon (AC), electrical conductive black carbon (BC)and thermoplastic binder. Effects of composition of electrode, particle size of activated carbon and weight proportion of poreprecursor on the charge/discharge performance of the cell were examined. Optimization was needed for the ratio of BC/ACunder the same amount of binder. It preferred to using activated carbon has large particle size for the mechanical stability ofthe electrode. Higher performance was obtained when more pore precursor was utilized. The power density output of up to0.14 W/cm 2 (1.19 V) was obtained when the porous carbon electrodes were applied. It was concluded that the activated carbon was an excellent electrode material with high performance/price ratio.: activated carbong pore precursorg energy storage cellg sodium polysulfideg bromine收稿日期 2004-06-05""""""基金项目 中国科学院领域前沿项目基金资助(DICP-K 2002 D 3 )""""""作者简介 周汉涛(1976 )a 男a 湖北省人a 博士研究生a 主要研究方向为燃料电池与化学工程0: ZHOU Han-tao(1976 )a male a candidate for Ph D.联系人 张华民电与普通商品不同a 难以储存a 所以电站的建造容量须满足最大电力需求0一些可再生能源如风能\光能需储能系统配合0一个有效的解决方法是建造储能系统a 在用电低谷时将富余的电能储存起来a 在用电高峰时提供电能a 降低电站最大容量a 保证电力平稳输出0电能的储存在预防电力供应灾难事件\军事应用等方面也具有重大意义0电能储存技术有许多a 其中化学电源储能技术由于不受地理位置与时间的限制a 具有很强的实用性0美国人Remick [1]发明了PSB 储能电池a 英国Innogy 公司致力于开发这一基于燃料电池技术的新型储能系统a 并建造了第一座商业化储能电厂[2]a 电容量达120 MWh a 最大输出功率15 MW a 已在2002年建成并投入使用a 这是目前世界上唯一商业化且规模最大的新型化学储能电厂0PSB 储能电池属液流电池a 功率和储存容量可以分开设计a 可以提供5~500 MW 的功率a 在常温常压下运行a 并且具有能量转化率高\启动速度块\充放电性能好\充放电切换迅速\使用寿命长\制造成本低\环境友好等特点a 和其它机械\热力\电磁储能技术相比有很强竞争力a 特别适用于MW 级大规模储能电站[2]a 可用于大功率可移动电源a 是电动汽车和不依赖空气推进潜艇的理想候选储能电池之一[3]a 可以与其它可再生能源联合使用[4,5]a 随着进一步的成本降低和性能提高a 相信在其它方面的应用也会越来越广0电极是电池关键部件a 要有一定的机械强度\良好的导电性\比较大的孔隙率a 在电解液中有良好的化学与电化学稳定性a 电极材料成本也是影响电池商业化的重要因素a 因此有必要研制廉价而又容易获得的电极材料0葛善海等用聚丙烯腈炭毡作为PSB 储能电池的正负极材料[6,7]9Zito 用活性炭颗粒作为溴电极材料[8]9文献[9]采用活性炭布作为溴电极9Zito 的空气-多硫化物电池[10]阳极电解质为多硫化物a 电极材料为Barnebey-Cheney 公司生产的活性炭9Zito 的铁-硫电池[11]所!1 电极特征参数 Tab.1 Characteristic parameters Of electrOdes!"#$Electrode No. !"#$Electrode materials 质量百分比MBSS pCICCI BgC % !"Thickness / 11 !"#Bulk resistivity /~cm1 BC / AC / PVDF 0.0 / 73.3 / 26.7 4.13 9.362 BC / AC / PVDF 3.3 / 70.0 / 26.7 4.20 0.733 BC / AC / PVDF 13.3 / 60.0 / 26.7 3.36 0.424 BC / AC / PVDF 23.3 / 50.0 / 26.7 3.74 0.305 BC / AC / PVDF 15.0 / 70.0 / 15.0 4.90 0.256 BC / AC / PVDF / NaBr 13.5 / 63.0 / 13.5 / 10.0 4.10 0.237 BC / AC / PVDF / NaBr 12.0 / 56.0 / 12.0 / 20.0 4.00 0.278 BC / AC / PVDF / NaCl 15.0 / 70.0 / 15.0 / 20.0 5.08 0.289 BC / AC / PVDF / NaCl 15.0 / 70.0 / 15.0 / 30.0 5.20 0.3910 BC / AC / PVDF 15.0 / 70.0 / 15.0 4.45 0.3611 BC / AC / PVDF 15.0 / 70.0 / 15.0 4.37 0.41! !"1011活性炭颗粒粒径分别为 120!120160!Notez The particle size of the electrode No. 10 and 11are 80-120,120-160 mesh respectively.用的硫氧化还原电极材料也是活性炭!本文介绍了PSB 储能电池正"负电极均使用活性炭电极的研究结果!1 实验部分1.1 膜的预处理采用钠型Nafion-117膜作为阳离子交换膜#膜在使用前需要进行预处理将氢型膜转化为钠型膜#并除去膜中有机的和无机的杂质[12]!先将膜放入5%的H 2O 2于353 K 的水浴中加热约1 h 以除去有机杂质#然后将膜用去离子水洗涤$将膜放在0.5 mol/L H 2SO 4溶液中于353 K 的水浴中加热约1 h 以除去无机杂质#将膜用去离子水洗涤$再将膜放在1.0 mol/L NaOH 溶液中于353 K 的水浴中加热约2 h #将膜转化为钠型#然后用去离子水洗涤!1.2 电极的制备将导电材料(BC #美国Cabot Corp. XC-72炭黑#以下同)"活性炭颗粒(AC #山西新华化工厂#比表面积830 m 2/g #以下同)"聚偏氟乙烯(PVDF #上海三爱富新材料有限公司#以下同)粉末以及造孔剂按一定质量比混合#置于模具中热压成型(电极参数见表1)#热压温度200 #电极的实际成型压力控制在2 MPa,热压时间30 min !电极自然冷却后#用20%乙醇水溶液浸渍电极#然后用1.0 mol/L 80 C NaOH 水溶液浸渍#最后用80 C 去离子水洗涤#直到造孔剂被去除!如不特别说明#活性炭颗粒直径40 80目#电极工作面积为5 cm 2!1.3 电池结构与工艺流程PSB 储能电池的组装如图1所示#阳离子交换膜的两侧为电极#两块极板为石墨板#石墨板上的沟槽为电解质流动通道#垫片为聚四氟乙烯垫片#两块端板为不锈钢板#端板上镶嵌聚四氟乙烯接头!PSB 储能电池流程如图2#正"负极的电解液经泵流入电池#在电极上发生电化学反应后流入各自的储罐中#中间用阳离子交换膜隔开#电池外接负载或者电源#电池及循环的电解液温度由温度自动控制器控制!阴极"阳极电解液储罐充氮气以防止氧气的干扰!实验项目如果不是特别标明#操作条件如下%电池评价温度为80 C #先充电再放电#充放电电流密度为100 mA/cm 2#阴极"阳极电解液体积为50 mL #循环量均保持为30 mL/min #充电初始阳极电解液为1.0 mol/L Na 2S 4#阴极电解液为4.0 mol/L NaBr #到50%充电状态后放电#即放电初始负极电解质为2.0 mol/L Na2S 2#正极电解液为2.0 mol/L NaBr+1.0 mol/L Br2!2 实验结果与讨论2.1 工作原理输送到PSB 储能电池的电解液发生电化学反应后流出电池#电极并不参与化学反应#在放电时负极电极反应为%(x +1)Na 2S x !2 Na ++x Na 2S x +1+2 e -x =1~4 (1) Na +通过阳离子交换膜到达正极#与溴发生电极反应%1151413121110987654321, 15. 端板End plate $2, 4, 7, 9, 12, 14. 衬垫Gasket $3.阳极板Anode plate $5, 11. 支撑架Frame $6. 阳极Anode $8. 阳离子交换膜Cation exchange membrane $10.阴极Cathode $13. 阴极板Cathode plate 图1 多硫化钠/溴储能电池结构图Fig.1 Structure of sodium polysulfide/bromine energy storage cell 负载或电源Load or power supply!"Negative !"Positive s图2 多硫化钠-溴储能电池流程示意图Fig.2 Schematic diagram of sodium polysulfide /bromine energystorage batteryBr 2+2 Na ++2 e -~2 NaBr (2) 放电时电池反应为1(X +l)Na 2S X +Br 2~X Na 2S X +l +2 NaBr (3) 充电时电极反应逆向进行O 常温常压下a 正极电位l.06~l.09 V a 负极电位!0.48~!0.52 V a 单电池开路电压为l.54~l.6l V O !"!#电极组成的影响四种不同组成的电极组装的电池性能如图3所示O 固定粘结剂使用量为26.7%a 当炭黑与活性炭比值为l3.3Z60.0时电池性能最好O 实验结果表明在粘结剂量一定时a 高导电材料和活性炭的比例存在最优值O 因为不加炭黑时由于活性炭本身导电性不好再加上绝缘的聚合物a 制得的电极电阻很大a 加入高导电炭黑后电阻下降很多a 有利于电池性能提高a 而活性炭用量减少导致电极反应面积降低a 从而降低电池性能O 粘结剂只起粘结作用a 电阻很大a 所以其用量需要优化以兼顾导电性能和机械强度的要求a 这是因为PSB 储能电池的电解液是循环流动的a 这要求电极具有较好的机械性能a 能承受电解液的冲刷a 如果用量过低其机械性能不稳定a 在组装电池和运行时发生电极破碎\炭颗粒脱落等现象O !"$##活性炭粒径的影响由活性炭组成的电极具有两种孔隙1颗粒之间形成的粗孔a 颗粒内部的细孔O 粗孔孔径较大彼此连通a 是反应物和离子电荷传输的主要通道a 其孔壁构成电极过程的主要反应表面[l3]O 所以活性炭颗粒越小a 形成的大孔越多a 有利于电极反应O 但从图4可看出a 存在一个最优颗粒粒径O 我们认为这是因为活性炭颗粒变小a 同样大小的电极所用活性炭颗粒数将增加a 而导电材料和粘结剂的颗粒数量不变a 造成炭颗粒之间的导电性和粘结性降低a 导致电极电阻上升 见表l 以及机械性能的下降O 实验过程中发现a 大颗粒压成的电极机械性能好a 不易破碎a 小颗粒压成的电极易破碎a 随着充放电的进行伴随炭颗粒的脱落a 颗粒越小损失越多a 小于l60目时充放电已不能进行O 从图5可看出a 随着炭颗粒粒径的减小a 在充电过程中电压上升幅度加大a 而放电过程的电压下降速度加快a 有效放电时间减少O 另外颗粒过细压成的电极过于紧密a 颗粒之间形成的孔连通性较差a 不利于电极反应的进行O 所以不宜用粒径小于l60目的活性炭来制备电极O!"%#造孔剂的影响加入造孔剂增加了电极内的粗孔a 有利于电池性能提高O 分别用NaBr \NaCl 作为造孔剂制备电极O 用NaBr 时a 四种材料的总质量保持恒定a 用NaCl 时其它三种材料质量保持恒定O 图6~图9显示随着造孔剂量的增加a 电池性能提高a 当造孔剂量到20%以上时电池性能已到最高点a 继续加大用量没有必要a 因为电极内大孔增多其机械强度必定下降O 从图8可看出a 充电电流密度达到l20 mA/cm 2 电压为l.98 V a020100 40140120 2.82.42.01.61.2 V /VJ /(mA cm )-2曰___充电Charge 9回___放电Discharge 9BC / AC / PVDF=0.0 / 73.3 / 26.7么___充电Charge 9’___放电Discharge 9BC / AC / PVDF=3.3 / 70.0 / 26.7▽___充电Charge 9▼___放电Discharge 9BC / AC / PVDF=l3.3 / 60.0 / 26.7O ___充电Charge 9.___放电Discharge 9BC / AC / PVDF=23.3 / 50.0 / 26.7图3 电极组成不同时电池电压-电流密度曲线Fig.3 Cell Voltage Vs . current density plots for cell with Various electrode compositions 么___充电Charge 9’___放电Discharge a 40~80 目Mesh▽___充电Charge 9▼___放电Discharge, 80~l20目MeshO ___充电Charge 9.放电___Discharge, l20~l60目Mesh图4 活性炭粒径不同时电池电压-电流密度曲线Fig.4 Cell Voltage Vs . current density plots for cell with Variousparticle size of actiVated carbon020100 401401202.42.01.61.2V /VJ /(mA cm )-22.21.81.41.040~80目Mesh 80~l20目Mesh........l20~l60目Mesh 图5 活性炭粒径不同时电池充放电电压-时间曲线Fig.5 Cell Voltage Vs . time plots for cell during charge/dischargewith Various particle size of actiVated carbon0210864t /h 2.42.01.61.2V /V0.0BC / AC / PVDF / NaBr = 15.0 / 70.0 / 15.0 / 0.09BC / AC / PVDF / NaBr = 13.5 / 63.0 / 13.5 / 10.09........BC / AC / PVDF / NaBr = 12.0 / 56.0 / 12.0 / 20.0图7 NaBr 含量不同时电池充放电电压-时间曲线Fig.7 Cell Voltage Vs . time plots for cell during charge/discharge with Various content of NaBr 同样电流密度输出电压为1.19 V 9即比功率达到0.14 W/cm 20从表1可看出造孔剂的使用增加了电极电阻9但这种影响较小0总的说来造孔剂增加了连通性好的孔9从而提高了电池性能0!"结论(1)活性炭制得的多孔电极具有较高的电化学活性9在80 C 下充电电流密度达到120 mA/cm 2(电压为1.98 V )9放电电流密度为120 mA/cm 2时输出电压为1.19 V 9即功率密度达到0.14 W/cm 20可见活性炭是一种高性价比的PSB 储能电池电极材料0(2)粘结剂量一定时9导电材料\活性炭比例存在最优值9粘结剂的量需兼顾导电性能和机械强度0粘结剂用量为26.7%时9炭黑与活性炭比值为13.3Z60.0的电池性能最好0(3)小颗粒活性炭制备的电极易破碎9在电池运行过程中出现炭颗粒脱落现象9所以活性炭颗粒粒径应不小于160目0(4)造孔剂的使用增加了电极的有效反应面积9改善了传质9从而提高了电池性能9当用量达20%后电池性能已达到最高点9继续加大用量作用不大反而会降低电极机械强度0参考文献:[1] REMICK R J, ANG P G P. Electrically rechargeable anionicallyactiVe reduction-oxidation electrical storage-supply system [P].US 4485154, 1984.[2] PRICE A, BARTLEY S, Male S, et al . A noVel approach to utilityscale energy storage [J].Power Eng J,1999,13(3):122 129.[3] LAKEMAN J B, BAMES P, CARNSTONE W, et al . The Rege- nesys fuel cell for air independent power [J]. Warship 99,1999,6:1 14.么 充电Charge 9A 放电Discharge 9BC / AC / PVDF / NaBr = 15.0 / 70.0 / 15.0 / 0.0① 充电Charge 9@ 放电Discharge 9BC / AC / PVDF / NaBr = 13.5 / 63.0 / 13.5 / 10.0▽ 充电Charge 9▼ 放电Discharge 9BC / AC / PVDF / NaBr = 12.0 / 56.0 / 12.0 / 20.0图6 NaBr 含量不同时电池电压-电流密度曲线Fig.6 Cell Voltage Vs . current density plots for cell with Various content of NaBr020100 401401202.42.01.61.2 V /VJ /(mA cm )-22.21.81.41.00210864t /h2.42.01.61.2 V /V 0.0 么 充电Charge 9A 放电Discharge 9BC / AC / PVDF / NaCl=15.0 / 70.0 / 15.0 / 0.0① 充电Charge 9@ 放电Discharge 9BC / AC / PVDF / NaCl = 15.0 / 70.0 / 15.0 / 20.0▽ 充电Charge 9▼ 放电Discharge 9BC / AC / PVDF / NaCl = 15.0 / 70.0 / 15.0 / 30.0图8NaCl 含量不同时电池电压-电流密度曲线Fig.8 Cell Voltage Vs . current density plots for cell with Variouscontent of NaCl020100 401401202.42.01.61.2V /VJ /(mA cm )-22.21.81.41.00210864t /h 2.42.01.61.2V /V0.0BC / AC / PVDF / NaCl = 15.0 / 70.0 / 15.0 / 0.09BC / AC / PVDF / NaCl = 15.0 / 70.0 / 15.0 / 20.09.......BC / AC / PVDF / NaCl = 15.0 / 70.0 / 15.0 / 30.0图9 NaCl 含量不同时电池充放电电压-时间曲线Fig.9 Cell Voltage Vs . time plots for cell during charge/dischargewith Various content of NaCl[4] PRICE A.The Regenesys energy storage system [A]. Renewable Energy Storage [C]. ImechE Semin: Professional Engineering Pub- lishing Ltd, 2000.11 24.[5] PRICE A, MCCARTHY L. Power generation using renewables and the Regenesys energy storage system [A]. Power Generation by Renewables [C]. ImechE Semin: Professional Engineering Publish- ing Ltd, 2000.195 206.[6] 葛善海, 衣宝廉, 付宇,等. 多硫化钠-溴新型再生燃料电池的研究[J]. 电源技术, 2002, 26(5):355 358.[7] 葛善海, 衣宝廉, 顾红星,等. 高效率多硫化钠/溴储能电池的研究[J]. 电池, 2003,33(1):12 14.[8] ZITO R. Zinc-bromine battery with long-term stability [P].UK GB 2132004, 1984.[9] MIYAGAWA H. Positive electrode of zinc-bromine battery [P]. JP 10064557, 1998.[10] ZITO R. Electrochemical apparatus for power delivery utilizationan air electrode [P]. WO 9409524, 1994.[11] ZITO R. Electrochemical energy storage and power delivery pro- cess utilizing iron-sulfur couple [P]. WO 9409525, 1994.[12] MURPHY O J, HITCHENS G D, MANKO D J. High power den-sity proton-exchange membrane fuel cells [J]. J Power Sources,1993, 47(3): 353 368.[13] 查全性. 电极过程动力学导论[M].第三版 北京 科学出版社,2002.346.图8 102 A 放电端电压及正负极镉电压曲线Fig.8 Voltage curves of battery and Cd electrode at 102 A 从图7~图8中可以发现 蓄电池C 10 和C 1容量是由正极容量控制 这与电池解剖结果基本一致 即蓄电池正极活性物质存在一定程度的软化与脱落 2.5 提高蓄电池循环特性的措施与建议2.5.1 提高蓄电池的充电接受能力显然 充电接受能力对蓄电池的循环特性起着非常重要的作用 假若每个循环中 存在很小的容量亏损 其累积起来的后果是极其严重的 蓄电池制造工艺应重点关注充电性能 与充电性能密切相关的是充电电压的选择 充电电压高 充电相对充分 但同时会带来正极板栅腐蚀~活性物质软化脱落及电池失水的加速等问题使蓄电池的寿命缩短 我们认为 在循环使用中,每个单体电池的充电电压不高于2.40 V 是恰当的 2.5.2 提高蓄电池的动态均匀一致性蓄电池均匀一致性的概念 不能仅局限于初始容量~负荷电压及浮充电压 应该是广义的 应涉及所有的零部件~原材料及制造过程 同时均匀一致性必须是动态的 贯穿于整个寿命周期 其中有两个关键项 一是蓄电池的气密性和阀的开闭压力 提高蓄电池槽~盖及封接的质量 确保电池在整个寿命期间气密性指标的合格 安全阀具备合适的开闭压力以及在整个寿命期间的稳定性 这些都有利于控制水的损耗 提高各单体之间水损耗的一致性 二是保持极板的法向压力及其均匀一致性 通过紧装配技术 在正极板法向保持40 kPa 的法向压力 有助于抑制正极活性物质膨胀 减少软化脱落 延长使用寿命[8] 其难点是如何保证在使用过程中压力不下降 这有待于进一步研究 总而言之 在现有技术水平的前提下 提高蓄电池的均匀一致性 是延长使用寿命的最有效途径之一 3 结论<1>试验温度对阀控免维护铅酸蓄电池循环放电深度有较大的影响<2>在1 h 放电循环过程中 阀控免维护铅酸蓄电池C 10和C 1容量同步下降<3>蓄电池单体不均衡率变差是循环用蓄电池提前失效的原因之一<4>在循环模式下的蓄电池最终失效原因是正极活性物质的软化~脱落<5>改善充电接受能力 提高各单体的均匀一致性 有助于提高阀控免维护铅酸蓄电池的循环特性 延长循环寿命 参考文献:[1] 吴贤章.循环用阀控电池失效模式的研究[J].蓄电池 2002 <4> 151 154.[2] 毕道治.电动车电池的开发现状及转弯展望[J].国际电源商情 2002 (8) 19 25.[3] TB/T 3061-2002 铁路机车车辆用阀控密封铅酸蓄电池[S].[4] 朱松然.蓄电池手册[M].天津 天津大学出版社 1998.59.[5] PAVLOV D.阀控式密封铅酸蓄电池国际讲学班讲义[M].中国杭州 2000.4.[6] 王震坡.电动汽车动力蓄电池组不一致性统计分析[J].电源技术 2003 <5> 438 441.[7] 高建峰.OTSLA 蓄电池均匀性的研究[J].电池工业 1999 (4)141.[8] FUCHIDA K. Towards improved manufacture of lead/acid batter ies panel discussion [J].J Power Sources, 1992,38:197 227.1.02.0V /V 0200.0 1.52.5!" Cd !"# Cell !" Cd 100 40t lmin (上接第166页)"!"!!!!!!!!!!!"!"。

真皮包覆装饰件鼓包缺陷研究及改进

真皮包覆装饰件鼓包缺陷研究及改进

10.16638/ki.1671-7988.2018.12.015真皮包覆装饰件鼓包缺陷研究及改进贾培娜,李国强(神龙汽车有限公司技术中心,湖北武汉430056)摘要:近些年,各大整车厂为了提升内饰感知质量,其中真皮装饰件的应用越来越多,而鼓包是真皮装饰件最多的售后抱怨点。

为了分析和解决该问题,我们从生产过程、使用环境和设计方面进行各种对比验证,并研究了不同使用环境、不同包覆工艺下真皮装饰件的外观表现。

研究表明,通过包覆工艺的调整,并注意真皮使用环境,能够解决真皮装饰件鼓包缺陷,保证可靠的外观性能。

关键词:真皮装饰件;鼓包;使用环境;无纺布中图分类号:U466 文献标识码:B 文章编号:1671-7988(2018)12-46-03Study and improvement on Bubble defect of Leather clad decorative partsJia Peina, Li Guoqiang( Shenlong Automobile Co., Ltd.. Technology Center, Hubei Wuhan 430056 )Abstract: In recent years, in order to improve the perception quality of interior decoration, the leather decoration is used more and more, and the drum bag is the most complaints point. In order to analyze and solve this problem, we compared and verified the production process, using environment and design, and studied the appearance of leather decoration under different application environment and different coating technology. The results show that by adjusting the coating process and paying attention to the use environment of the dermis, the defects of the drum can be solved and the reliable appearance can be guaranteed.Keywords: leather ornaments; drum bags; environmental non-woven fabricsCLC NO.: U466 Document Code: B Article ID: 1671-7988(2018)12-46-031 概述很多人购车时,会优先选购真皮装饰这项配置,觉得真皮装饰更有档次,更有质感,舒适并且耐脏。

鞣制过程中皮革在转鼓内的形变特征及受力分析

鞣制过程中皮革在转鼓内的形变特征及受力分析

doi:10.19677/j.issn.1004-7964.2024.01.001鞣制过程中皮革在转鼓内的形变特征及受力分析韩明真1,2,江卓成3,谢果3,曾运航1,2,王亚楠1,2*(1.四川大学制革清洁技术国家工程实验室,四川成都610065;2.四川大学轻工科学与工程学院,四川成都610065;3.四川大学水利水电学院,四川成都610065)摘要:研究了鞣制过程不同转速下皮革在转鼓中的形变和受力过程。

首先将转鼓内皮革的复杂形变过程简化为圆到椭圆的周期性形变过程,建立了形变计算模型。

随后通过可视化实验定量分析了转鼓内皮革的形变及受力情况,证明该模型具有合理性。

此外,在鞣制初期使用高转速(如15r/min),在末期使用低转速(如5r/min),可使皮革保持较大的形变程度和推力,从而利于化学品的传质,提升鞣制效果,助力皮革行业节能增效。

关键词:皮革;转鼓;鞣制;形变;受力分析中图分类号:TS 54文献标志码:ADeformation Mechanism and Force Analysis of Leather in Drum(1.National Engineering Laboratory for Clean Technology of Leather Manufacture,Sichuan University,Chengdu 610065,China;2.College of Biomass Science and Engineering,Sichuan University,Chengdu 610065,China;3.College of WaterResource &Hydropower,Sichuan University,Chengdu 610065,China)Abstract:The deformation and force-bearing processes of leather in drum during tanning were investigated under different rotating speeds.The complicated deformation process of leather in drum was first simplified to a periodic process from a circle to an oval,and the calculation model of deformation was established.Then the deformation and force-bearing processes of leather in the drum were quantitatively validated through visualization experimental data.It was proven that this model was scientifically sound.Moreover,using high speed (such as 15r/min in this experiment)at the beginning of tanning and low speed (such as 5r/min in this experiment)at the end of tanning can result in large deformation and pushing force of leather,thereby benefiting the mass transfer of leather chemicals and enhancing tanning performance.The obtained results are expected to improve the energy conservation of leather industry.Key words:leather;drum;tanning;deformation;force analysis收稿日期:2023-07-25修回日期:2023-08-23接受日期:2023-08-30基金项目:四川省自然科学基金(2022NSFSC1180);四川大学“大学生创新创业训练计划”项目(C2023124137)第一作者简介:韩明真(2002-),男,本科生,主要研究方向:制革过程传质动力学。

dinocap

dinocap

dinocapDinocap: The Revolutionary Solution for Crop ProtectionIntroduction:In the world of agriculture, one of the biggest challenges faced by farmers is crop protection. Pests, diseases, and weeds can cause significant damage, leading to substantial losses in yield and revenue. Over the years, scientists and researchers have been tirelessly working towards finding effective solutions to combat these challenges. One such breakthrough invention that has been gaining widespread attention among farmers and agricultural experts is Dinocap. In this article, we will delve into the details of Dinocap and explore why it is considered a game-changer in the field of crop protection.What is Dinocap?Dinocap, also known as the chemical compoundbis(dimethylthiocarbamoyl) disulfide, is a synthetic pesticide widely used in agriculture. It belongs to the class of compounds known as dithiocarbamates, which are highlyeffective against a broad spectrum of pests and diseases. Dinocap is primarily used as a fungicide and miticide, making it invaluable for protecting crops against fungal infections and mite infestations.Modes of Action:Dinocap acts by inhibiting the energy production process within the cells of pests and fungal pathogens. It interferes with the mitochondrial respiration, leading to a disruption of the energy balance. This ultimately results in the death of the pests or the suppression of the fungal growth. The unique mode of action of Dinocap makes it an excellent tool for managing fungicide resistance and preventing pests from developing resistance to the compound.Advantages of Dinocap:1. Broad-spectrum activity: One of the significant advantages of Dinocap is its broad-spectrum activity against a wide range of pests and diseases. It is effective against various species of mites, powdery mildew, rust, and other fungal pathogens. This versatility makes Dinocap a go-to solution for farmers facing multiple crop protection challenges.2. Long-lasting protection: Dinocap provides long-lasting protection to crops. It can persist on the plant surfaces, providing a preventive barrier against pests and diseases for an extended period. This characteristic is particularly beneficial in situations where the risk of reinfestation or re-infection is high.3. Residue management: Dinocap has low persistence in the environment and can be easily degraded into non-toxic compounds. This feature ensures that crops treated with Dinocap can meet the stringent residue regulations imposed by various regulatory authorities.4. Compatible with integrated pest management (IPM): Dinocap can be integrated into IPM programs effectively. It is compatible with other control methods, such as biological control agents and cultural practices, allowing farmers to adopt a holistic approach to crop protection.5. Cost-effective: Compared to other pest control measures, Dinocap is a cost-effective option for farmers. Its broad-spectrum activity and long-lasting protection minimize the need for multiple applications, reducing overall costs.Safety Considerations:While Dinocap offers numerous benefits for crop protection, it is crucial to consider safety when using the compound. It is essential to follow the instructions and recommendations provided by the manufacturer and regulatory authorities to minimize any potential risks associated with Dinocap. Protective equipment such as gloves and masks should be used during handling and application to ensure personal safety.Regulatory Approval:Dinocap has been approved for use in many countries around the world, including the United States, European Union, and China. Regulatory bodies carefully evaluate the safety and efficacy of pesticides before granting approval for their use in agriculture. These approvals provide reassurance to farmers that Dinocap can be used in a responsible and sustainable manner.Conclusion:Dinocap represents a significant advancement in the field of crop protection. With its broad-spectrum activity, long-lasting protection, and compatibility with integrated pest management, it has emerged as a revolutionary solution for farmers. However, it is important to emphasize the proper and responsible use of Dinocap to ensure the continued effectiveness and the safety of farmers, consumers, and the environment. With continued research and development, Dinocap and other innovative solutions will continue to shape the future of agriculture, enabling farmers to protect their crops and contribute to global food security.。

环形束激光熔覆CuPb10Sn10_减摩涂层组织性能调控

环形束激光熔覆CuPb10Sn10_减摩涂层组织性能调控

表面技术第52卷第7期激光表面改性技术环形束激光熔覆CuPb10Sn10减摩涂层组织性能调控程梦颖a,石拓b,万乐a,魏超a,张荣伟a,蔡家轩a,袁德涛a (苏州大学 a.机电工程学院 b.光电科学与工程学院,江苏 苏州 215000)摘要:目的为了从原理上改良汽车关键零部件特定表面的减摩性能,提出环形激光熔覆高质量CuPb10Sn10铜合金异质涂层提升零部件耐磨减摩性能的方法。

方法设计单层熔覆、顶部重熔、逐层重熔3种制备方案,采用环形束激光熔覆技术在42CrMo钢表面制备熔覆层。

分析试样的表面形貌、孔隙率、物相构成,并分析熔覆层–基材的结合强度及耐磨减摩效果。

结果基于环形激光熔覆单层熔覆层设计的逐层重熔和顶部重熔制备工艺方法均能在42CrMo钢表面实现厚1 mm减摩涂层的成功制备。

单层熔覆在熔覆过程及环境参数改变范围内的质量提升效果有限,缺陷分布明显且难以控制;顶部重熔过程中热量分布特征导致的Marangoni效应未使熔覆质量实现有效优化,熔覆层内部孔洞、裂纹、热影响区(HAZ)等缺陷未显著减少;逐层重熔法制备的熔覆层质量大幅提升,制备过程显微组织变化过程为:不均匀网状分布–独立棒状分布–“芝麻”状分布,且发现“芝麻”状分布SPP(富铅第二相粒子)的减摩效果优于独立棒状分布SPP。

熔覆层出现偏析分层,且凝固过程晶粒长大生成柱状枝晶。

逐层重熔法制备的CuPb10Sn10熔覆层孔隙率不高于0.5%,摩擦因数较原始基材表面下降量可达75%。

结论实现了碳钢材料零部件表面高性能耐磨减摩涂层的成功制备,为汽车制造等工业零部件设计与生产提供了新的思路及工艺理论指导。

关键词:环形束激光;CuPb10Sn10;异质结合;显微组织;耐磨性能;减摩性能中图分类号:TN249文献标识码:A 文章编号:1001-3660(2023)07-0336-12DOI:10.16490/ki.issn.1001-3660.2023.07.031Performance Regulation of Annular Laser Cladding CuPb10Sn10Anti-friction Coating MicrostructureCHENG Meng-ying a, SHI Tuo b, WAN Le a,WEI Chao a, ZHANG Rong-wei a, CAI Jia-xuan a, YUAN De-tao a收稿日期:2022–06–14;修订日期:2022–10–25Received:2022-06-14;Revised:2022-10-25基金项目:国家自然科学基金(62173239)Fund:National Natural Science Foundation of China (62173239)作者简介:程梦颖(1998—),女,硕士生,主要研究方向为激光增材制造。

产品过度包装的影响英语作文

产品过度包装的影响英语作文

产品过度包装的影响英语作文English: Excessive packaging of products has several negative impacts on the environment, consumers, and businesses. Firstly, it contributes to the excessive generation of waste and pollution. The use of unnecessary packaging materials, such as plastic, can lead to increased landfill space and ocean pollution. Moreover, the production and disposal of excessive packaging materials contribute to high energy consumption and greenhouse gas emissions, further exacerbating climate change. Secondly, over-packaging can also result in higher costs for consumers. The added expenses of excessive packaging are often passed on to consumers, leading to increased prices for products. This can especially impact lower-income individuals who may struggle to afford these inflated prices. Lastly, businesses may also suffer from the effects of over-packaging, as consumers become more environmentally conscious. Companies that fail to adopt sustainable packaging practices may face backlash from consumers and encounter challenges in maintaining a positive brand image. Therefore, it is crucial for businesses to prioritize sustainable packaging solutions to minimize the negative impacts of over-packaging.Translated content: 产品过度包装对环境、消费者和企业产生了多种负面影响。

食品安全与包装材料的阻隔性课件

食品安全与包装材料的阻隔性课件

RH (%)
Additives used in manufacturing or modifying the polymer 添加物用于高分子的加工和改性
PVC
Poly(vinyl chloride)
Material state
Pure, rigid Plasticized,
PVC
soft PVC
H 2C
CH
17
C
O
OCH 3
Poly(vinyl chloride)
H2C
CH
8
Cl
Low polarity, very little cohesion between chains
Chains are a little stiffer, but very little cohesion or attraction
传感器法
标准
ASTM E-96 TAPPI T-464 JIS Z-0208 湿度传感器法
ISO 15106-1:2003(E)
红外传感器法 (MOCON专利)
电解传感器法
ISO 15106-2:2003(E) ASTM F-1249 TAPPI T-557 JIS K-7129
ISO 15106-3:2003(E)
影响阻隔性的因素 ----- 温度
o 温度每升高1C, 渗透率增加 5 to 7%
o -----同样材料的 渗透率在热带地 区与寒带地区会 不一样
Permeation Rate (g/m2-day)
Temperature (C)
影响阻隔性的因素 ---- 湿度
o ----- 某些材料 的阻隔性在潮 湿环境与干燥 环境会不一样
o 渗透率与渗透物浓度成正 比 (Ficken材料)

有关产品过度包装的影响的英语作文

有关产品过度包装的影响的英语作文

有关产品过度包装的影响的英语作文英文回答:Excessive Product Packaging: An Eco-Hazard.Excessive product packaging is a pressing environmental issue that has detrimental effects on the planet and its ecosystems. It generates an alarming amount of waste, depletes natural resources, and contributes to climate change.Environmental Consequences:Increased Waste Generation: Packaging materials, often derived from nonbiodegradable materials such as plastic, end up in landfills or as litter, polluting the environment for centuries.Resource Depletion: The production of packaging materials consumes precious natural resources, such astimber and fossil fuels, leading to deforestation and carbon emissions.Contribution to Climate Change: The production and disposal of packaging materials release greenhouse gases, exacerbating global warming.Economic Costs:Increased Costs for Businesses: Excessive packaging raises production costs for businesses, which are ultimately passed on to consumers.Financial Burden on Consumers: Consumers often pay a premium for products with unnecessary packaging, adding to their financial burden.Health Hazards:Toxic Chemicals: Some packaging materials contain toxic chemicals that can leach into products, posing potential health risks to consumers.Environmental Pollution: Non-biodegradable packaging materials litter the environment, creating breeding grounds for pests and disease.Solutions to Excessive Packaging:Establish Sustainable Packaging Standards: Governments and industry leaders should set standards for eco-friendly packaging materials to reduce waste and environmental impact.Promote Reusable and Recyclable Packaging: Encourage the use of reusable containers and promote recycling programs to minimize waste.Educate Consumers and Businesses: Raise awareness about the harmful effects of excessive packaging and encourage responsible purchasing and production practices.Innovation and Technology: Invest in research and development to find innovative and sustainable packagingsolutions that reduce waste and environmental impact.中文回答:过度产品包装,环境隐患。

磷酸盐对定量卤制酱牛肉水分分布和微观结构的影响

磷酸盐对定量卤制酱牛肉水分分布和微观结构的影响

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The effects of laser shucking, laser-bleaching shucking and laser-steam shucking on the sensory,nutritional and taste quality of mussel meat were investigated using the traditional boiling shucking and the manual shucking as control. The results showed that when the laser power was 40 W and the treatment time was 0.5 s, the shucking rate of the adductor muscle was 100%, and the color and odor sensory scores were high. The hardness, springiness and chewiness of mussel meat obtained by laser and its combined shucking technologies were close to fresh mussel meat, and the loss of protein, fat, carbohydrate and 5′-nucleotide was reduced compared with boiling shucking ser-bleaching shucking and laser-steam shucking also increased the content of free amino acids in mussel meat (P<0.05).Therefore,laser and its combined shucking technologies could effectively improve the shucking rate, reduce the nutritional loss of mussel meat during processing, and obtain fresh shucked mussel meat with good quality. The results of this study provide a theoretical basis for the further application of laser technology in shellfish shucking.Keywords: mussel, laser shucking, combined shucking technologies, quality change, free amino acid998核农学报2023,37(5):0999~1004Journal of Nuclear Agricultural Sciences磷酸盐对定量卤制酱牛肉水分分布和微观结构的影响李雪张耀程文龙刘光宪*王丽(江西省农业科学院农产品加工研究所,江西南昌330200)摘要:为探究复合磷酸盐对定量卤制酱牛肉水分分布和微观结构的影响,本研究采用低场核磁共振技术(LF-NMR)对不同磷酸盐添加量的酱牛肉水分分布和迁移规律进行分析,并研究不同磷酸盐添加量对定量卤制酱牛肉微观结构和质构特性的影响。

219401833_两种包装材料结合真空贮藏对油炸脆枣货架期的预测

219401833_两种包装材料结合真空贮藏对油炸脆枣货架期的预测

杜雨桐,陈恺,承春平,等. 两种包装材料结合真空贮藏对油炸脆枣货架期的预测[J]. 食品工业科技,2023,44(13):349−355. doi:10.13386/j.issn1002-0306.2022040219DU Yutong, CHEN Kai, CHENG Chunping, et al. Prediction of the Shelf Life of Fried Crispy Dates by Combining Two Packaging Materials with Vacuum Storage[J]. Science and Technology of Food Industry, 2023, 44(13): 349−355. (in Chinese with English abstract). doi: 10.13386/j.issn1002-0306.2022040219· 贮运保鲜 ·两种包装材料结合真空贮藏对油炸脆枣货架期的预测杜雨桐1,陈 恺1, *,承春平1,许铭强2,王雪妃1,王 田1,李焕荣1(1.新疆农业大学食品科学与药学学院,新疆果品精深加工与贮运保鲜工程技术研究中心,新疆乌鲁木齐 830052;2.新疆农业科学院农产品贮藏加工研究所,新疆乌鲁木齐 830091)摘 要:为探究低温油炸脆枣贮藏过程中品质劣变规律,采用PET 真空包装、PET 真空+脱氧剂包装、铝箔真空包装、铝箔真空+脱氧剂四种包装方式,分析不同贮藏温度(25、35、45 ℃)下酸价和过氧化值的变化,结合Arrhenius 公式建立低温油炸脆枣货架期的预测模型。

结果表明:不同贮藏温度下四种包装方式的油炸脆枣的酸价、过氧化值呈上升趋势,25 ℃变化速率低。

从包装效果来看,铝箔真空+脱氧剂包装方式油炸脆枣的氧化速率最低(酸价动力学模型K 值=0.0131,过氧化值动力学模型K 值=0.0147),预测货架期模型R 2>0.90,拟合度良好,货架期预测值模型误差小于10%。

T_型接头旋转激光+GMAW_复合焊熔池动态行为数值分析模型

T_型接头旋转激光+GMAW_复合焊熔池动态行为数值分析模型

第16卷第4期精密成形工程行为数值分析模型王艺瑾1,刘文1,胥国祥1*,朱杰1,胡庆贤1,杜宝帅2,龚祺龙1(1.江苏科技大学江苏省先进焊接技术重点实验室,江苏镇江 212000;2.国网山东省电力公司电力科学研究院,济南 250002)摘要:目的研究T型接头旋转光纤激光+GMAW复合焊熔池的温度场和流态特征,揭示气孔缺陷的产生及抑制机理。

方法依据光学、电磁学、传热学及流体动力学机理,建立T型接头旋转光纤激光+GMAW复合焊熔池数值分析模型。

使用Fluent软件对旋转频率分别为50 Hz和100 Hz的T型接头旋转激光+GMAW复合焊进行温度场以及流态特征的模拟,对比不同频率下T型接头横、纵截面,从工艺和焊缝成形角度出发,针对不同频率对熔池、小孔成形以及气孔抑制的影响进行讨论。

结果当旋转频率为50 Hz时,纵截面内小孔最大深度为5.4 mm,横截面熔池内小孔开口直径相对较大,旋转一周后,小孔远离气泡,气泡无法逸出,形成气孔;当旋转频率为100 Hz时,纵截面内小孔深度显著降低,熔池体积明显减小,横截面内小孔最大开口直径和深度均降低,熔池尺寸也有所减小,在时间为0.097 s时,小孔上方区域出现的顺时针涡流不仅能抑制气孔,还能改善熔池的下垂以及立板焊趾处的咬边。

结论随着旋转频率的增大,小孔的最大开口直径和深度均降低,还对熔池具有搅拌作用,使熔池体积变小。

关键词:T型接头旋转激光+GMAW焊;数值分析;旋转频率;小孔;气孔DOI:10.3969/j.issn.1674-6457.2024.04.018中图分类号:TG456.7 文献标志码:A 文章编号:1674-6457(2024)04-0147-08Numerical Analysis Model for Dynamic Behavior of Molten Pool inRotating Laser+GMAW Hybrid Welding of T JointsWANG Yijin1, LIU Wen1, XU Guoxiang1*, ZHU Jie1, HU Qingxian1, DU Baoshuai2, GONG Qilong1(1. Key Laboratory of Advanced Welding Technology, Jiangsu University of Science and Technology, Jiangsu Zhenjiang 212000,China; 2. State Grid Shandong Electric Power Research Institute, Jinan 250002, China)ABSTRACT: The work aims to study the temperature field and flow characteristics of molten pool in rotating laser+GMAW hybrid welding of T-joints, to reveal the generation and inhibition mechanisms of pore defects. According to the optics, electro-magnetic, heat transfer and fluid dynamics mechanisms, a numerical analysis model of molten pool in rotating laser+GMAW hybrid welding of T-joints was established. The temperature field and flow characteristics of the T-joint rotating laser+GMAW收稿日期:2023-12-28Received:2023-12-28基金项目:国家自然科学基金(51975263,52375340)Fund:The National Natural Science Foundation of China (51975263, 52375340)引文格式:王艺瑾, 刘文, 胥国祥, 等. T型接头旋转激光+GMAW复合焊熔池动态行为数值分析模型[J]. 精密成形工程, 2024, 16(4): 147-154.WANG Yijin, LIU Wen, XU Guoxiang, et al. Numerical Analysis Model for Dynamic Behavior of Molten Pool in Rotating La-ser+GMAW Hybrid Welding of T Joints[J]. Journal of Netshape Forming Engineering, 2024, 16(4): 147-154.*通信作者(Corresponding author)148精密成形工程 2024年4月hybrid welding at rotation frequencies of 50 Hz and 100 Hz were simulated by Fluent software. Then, the screenshots of cross and longitudinal sections of the joints were compared. From the perspective of process optimization and seam forming, the ef-fect of different rotation frequencies on the molten pool and keyholes and the inhibition mechanism of pore was discussed.When the rotation frequency was 50 Hz, the maximum depth of keyhole in the longitudinal section was 5.4 mm. The opening diameter of the keyhole in the cross section was relatively large. After rotation for a cycle, the keyhole was far away from the bubble and the bubble could not overflow, forming the pore. When the rotation frequency was 100 Hz, the depth of keyhole in the longitudinal section was significantly reduced just as the volume of the molten pool. In the cross section, the maximum opening diameter and the depth of keyhole were reduced respectively just as the size of the molten pool. When the time was0.097 s, the clockwise vortex in the area above the keyhole was conducive to reducing the sagging phenomenon in the moltenpool and the undercut phenomenon at the weld toe of the vertical plate, inhibiting the pore. With the increase of rotation fre-quency, the maximum opening diameter and depth of the keyhole decrease, which has a stirring effect on the molten pool, mak-ing the volume of molten pool smaller.KEY WORDS: laser+GMAW hybrid welding of T-joints; numerical analysis; rotation frequency; keyhole; pore激光电弧复合焊具有能实现优质、高效焊接的巨大潜力。

厚壁铝合金摇动电弧窄间隙GMAW焊缝气孔分布与成形

厚壁铝合金摇动电弧窄间隙GMAW焊缝气孔分布与成形

第35卷第2期2021年4月 江苏科技大学学报(自然科学版)JournalofJiangsuUniversityofScienceandTechnology(NaturalScienceEdition) Vol 35No 2Apr.2021 DOI:10.11917/j.issn.1673-4807.2021.02.004厚壁铝合金摇动电弧窄间隙GMAW焊缝气孔分布与成形陈琪昊,杨 帆,朱 杰,王加友(江苏科技大学材料科学与工程学院,镇江212100)摘 要:严重的气孔缺陷和不良的焊缝成形会影响厚壁铝合金窄间隙熔化极气体保护焊(narrowgap gasmetalarcwelding,NG GMAW)的焊接质量.文中针对摇动电弧NG GMAW焊缝气孔分布及成形进行研究,为实际焊接应用提供指导.研究了电弧摇动角度、摇动频率及侧壁停留时间对焊缝气孔分布及焊缝成形的影响规律,探讨了焊缝气孔分布与成形之间的关系,分析了电弧摇动对焊缝成形和气孔分布的影响机制.研究表明:电弧摇动对焊缝气孔分布及成形有直接的影响,焊缝气孔缺陷与焊缝成形之间存在明确联系,良好的焊缝成形对应着较低的气孔率.关键词:窄间隙熔化极气体保护焊;厚壁铝合金;气孔分布;焊缝成形中图分类号:TG444 文献标志码:A 文章编号:1673-4807(2021)02-024-06收稿日期:2019-10-29 修回日期:2020-04-28基金项目:江苏科技大学引进博士科研启动基金资助项目(1062931808)作者简介:陈琪昊(1988—),男,工学博士,讲师,研究方向为有色金属高效化焊接及质量控制.E mail:qhchen@just.edu.cn引文格式:陈琪昊,杨帆,朱杰,等.厚壁铝合金摇动电弧窄间隙GMAW焊缝气孔分布与成形[J].江苏科技大学学报(自然科学版),2021,35(2):24-29.DOI:10.11917/j.issn.1673-4807.2021.02.004.PoredistributionandformationinswingarcnarrowgapGMAWweldofthick walledaluminumalloyCHENQihao,YANGFan,ZHUJie,WANGJiayou(SchoolofMaterialsScienceandEngineering,JiangsuUniversityofScienceandTechnology,Zhenjiang212100,China)Abstract:Severeporeproblemandpoorweldformationaffecttheweldingqualityofnarrowgapgasmetalarcwelding(NG GMAW)ofthick walledaluminumalloy.Inthispaper,theporedistributionandweldformationinthenarrowgapweldingofshakingarcareinvestigatedtoprovidetheguidanceforpracticalweldingapplications.Theeffectsofswingangle,swingfrequencyandresidencetimeinthesidewallonthedistributionofweldporosi tyandweldformationareanalyzedindetail.Therelationshipbetweentheweldporosityandformationisdis cussed.Theinfluencemechanismofswingarconweldporosityandformationisanalyzed.Theresultsshowthatthearcswinghasadirecteffectonthedistributionofweldporosityandformation,andthereisaclearconnectionbetweentheweldporositydefectsandtheweldformation.Goodweldformationcorrespondstolowporosity.Keywords:NG GMAW,thick walledaluminumalloy,poredistribution,weldformation 铝合金具有密度低、耐腐蚀性好、强度高及可焊性好等优点,在船舶、航空航天及核工业等领域具有重要的工程应用价值[1].随着现代工业的发展,大型结构的焊接需求越来越多,厚壁铝合金的焊接问题愈发显得重要.传统的厚壁铝合金非窄间隙熔化极气体保护焊方法存在焊接热输入大、焊接效率低及接头软化等问题[2].窄间隙熔化极气体保护焊(NG GMAW)与非窄间隙焊接方法相比,具有热输入低、节约材料及焊接效率高等优点[3-5],是一种理想的厚壁铝合金焊接方法.对于窄间隙焊接特有的侧壁熔合不良问题,国内外学者先后提出电弧摇动(摇动电弧属于摆动电弧一种,摇动电弧摆动路线为弧形,为区别于电弧的横向直线摆动,在概念上称为摇动电弧)或旋转的焊接方法[6-7],有效地解决了此问题.受铝合金材料本身特性的影响,厚壁铝合金NG GMAW气孔问题一直未见较好的解决方案,焊缝气孔与成形是影响铝合金NG GMAW焊接质量的两个重要因素.焊缝气孔分布与焊缝成形之间是否存在一定的联系,从而可通过优化焊缝成形减小焊缝气孔缺陷.针对此问题,文中在摇动电弧NG GMAW基础上开展了焊缝气孔分布与焊缝成形关系的研究,为厚壁铝合金摇动电弧NG GMAW工艺优化提供指导.1 焊接设备及实验方法1 1 焊接设备焊接设备示意如图1,主要由焊接电源、送丝机、焊炬、保护气及工作台组成.焊炬的构造是实现电弧摇动的关键,在焊炬内部,弯曲导电杆和空心轴电机相连,在空心轴电机的驱动下,弯曲导电杆带动电弧在窄间隙坡口内进行弧形摇动,电弧摇动轨迹如图2,电弧摇动可控参数为摇动频率、摇动角度及侧壁停留时间.1 2 实验方法对厚壁5083铝合金进行摇动电弧NG GMAW,焊丝选用ER5183.焊接过程中,电弧在窄间隙坡口内左右摇动,并在侧壁处进行短暂停留,以增加侧壁热输入,抑制侧壁未熔合缺陷的形成.图1 焊接设备示意Fig.1 Schematicofweldingequipment图2 电弧摇动轨迹示意Fig.2 Schematicofarcswingpath实验参数如表1,固定焊接参数,仅改变电弧摇动参数,分析电弧摇动作用下焊缝气孔分布与成型之间的关系.根据焊接经验,当摇动频率为1Hz、侧壁停留时间为100ms、摇动角度为30°的参数组配时,焊接质量较好.因此,电弧摇动参数围绕.焊接电流为350A、焊接速度为240mm/min、气流量为25L/min进行设定.实验过程中仅改变电弧摇动频率、摇动角度及侧壁停留时间.表1 焊接工艺参数Table1 Weldingexperimentparameters实验序号摇动频率/Hz侧壁停留时间/ms摇动角度/(°)11402521403031403240 5403051 54030624030711003081120309116030 焊接试板规格为200mm×150mm×30mm,采取U型坡口,坡口凹槽深度为25mm,坡口凹槽钝边厚度为10mm,坡口形式示意如图3.图3 试验焊件坡口形式Fig.3 Schematicofweldinggroovestructure对试样件进行单层摇动电弧GMA焊接,利用光学显微镜及Image ProPlus软件对横截面内气孔分布及焊缝成形进行统计分析.在分析数据时,考虑到焊缝截面形状变化的影响,在计算气孔率时以实际焊缝截面积为分母进行计算,利用Image ProPlus软件测量了不同焊接参数下的焊缝截面积Sw及焊缝截面上的气孔面积Sg,取气孔面积总和,气孔率为:η=∑SgSw气孔率从宏观上反应了焊缝截面整体气孔率大小,焊缝截面整体气孔率大小同焊缝性能具有直接的联系,因此,文中计算的焊缝截面气孔率具有一定的参考意义.2 实验结果与分析2 1 焊缝截面气孔分布规律固定其他参数,仅改变电弧摇动频率f,焊缝宏观气孔分布如图4,结果表明:当摇动频率f为52第2期 陈琪昊,等:厚壁铝合金摇动电弧窄间隙GMAW焊缝气孔分布与成形0 5、2 0Hz时,大气孔主要分布于焊缝上部;当摇动频率为1 0、1 5Hz时,气孔分布相对比较均匀,在焊缝上部没有产生大气孔聚集现象.从此可以看出,焊缝气孔分布对电弧摇动频率具有较强的敏感性.改变电弧摇动频率,可以直接改变焊缝截面气孔的分布.图4 摆动频率对气孔分布的影响Fig.4 Effectofswingfrequencyonporedistribution对不同摇动频率下的宏观气孔直径D分布及气孔率η(面积覆盖率)进行分析,结果如图5.图5 摇动频率对气孔尺寸分布及气孔率的影响Fig.5 Effectofswingfrequencyonporesizedistributionandporosity 统计结果表明,当摇动频率由0 5Hz增加到1 5Hz时,集中在焊缝上部分的大尺寸气孔数量n逐渐减少,分布在焊缝中的小尺寸气孔数量增多;当摇动频率由1 5Hz增加到2 0Hz时,位于焊缝上部的大尺寸气孔数量及焊缝内部的小尺寸气孔数量均逐渐增多.宏观气孔覆盖率随摇动频率增加呈现先下降后上升的趋势,当摇动频率为1 5Hz时,焊缝宏观气孔覆盖率最小.当摇动频率为2Hz时,焊缝宏观气孔覆盖率最大.电弧摇动对熔池流动具有搅拌作用,在一定程度内有助于熔池内气泡逸出,电弧摇动频率越大,搅拌作用越强,但是当摇动频率过大时,对熔池内气泡逸出起到了抑制作用.改变电弧摇动角度,电弧摇动角度θ分别为25°、30°及32°,焊缝宏观气孔分布如图6,结果表明,当摇动角度θ为25°及30°时,气孔分布比较均匀;当摇动角度为32°时,气孔分布发生了明显变化,焊缝宏观气孔尺寸较大.在焊缝上部区域,大气孔分布密度较大.图6 电弧摇动角度对气孔分布的影响Fig.6 Effectofarcswingangleonporedistribution不同电弧摇动角度下的焊缝宏观气孔尺寸分布及面积覆盖率如图7,当摇动角度为25°及30°时,小气孔数量较多.摇动角度为32°时,大尺寸气孔数量增多.当摇动角度从25°到32°时,宏观气孔覆盖率呈现先下降后上升的趋势,当摇动角度为30°时,焊缝宏观气孔覆盖率最小.改变电弧侧壁停留时间,侧壁停留时间t分别设为40、100、120、160ms.焊缝宏观气孔分布如图8,结果表明,随侧壁停留时间增加,焊缝宏观气孔尺寸逐渐增大,大尺寸气孔逐渐聚集于熔合区附近.62江苏科技大学学报(自然科学版)2021年图7 摇动角度对气孔尺寸分布及气孔率的影响Fig.7 Effectofswingangleonporesizedistributionandporosity图8 不同侧壁停留时间下焊缝气孔分布Fig.8 Effectofsidewalldwelltimeonporedistribution面积覆盖率随侧壁停留时间的增大先减小后增大,当侧壁停留时间为100ms时,焊缝宏观气孔覆盖率最低,为1 04%.当侧壁停留时间为160ms时,焊缝宏观气孔覆盖率最大,为2 28%.通过计算,得出不同侧壁停留时间下的焊缝宏观气孔尺寸分布及面积覆盖率,如图9.当侧壁停留时间为100ms时,焊缝中气孔数量最少,其中大部分为小尺寸气孔.当侧壁停留时间为40ms时,小尺寸气孔数量较多.当侧壁停留时间为120ms时,气孔数量增多.当侧壁停留时间为160ms时,焊缝截面中的气孔数量进一步增多,小尺寸气孔数量依旧占据总气孔数量的大部分.在侧壁停留时间由100ms增加到160ms时,大尺寸气孔数量不断减少.图9 侧壁停留时间对气孔尺寸分布及气孔率的影响Fig.9 Effectofsidewalldwelltimeonporesizedistributionandporosity2 2 焊缝成形规律不同电弧摇动频率下的焊缝宏观成形情况也可通过图4进行分析,发现当电弧摇动频率为1Hz时,焊缝成形质量较好,左右对称良好.当电弧摇动频率为2Hz时,焊缝成形质量较差,出现了明显的非对称特征.通过软件对焊缝截面尺寸d进行测量,得到不同摇动频率f下的焊缝截面凸起高度和侧壁熔深,如图10.随电弧摇动频率的增大,侧壁熔深及凸起高度均先减小后增大.当摇动频率为1 0Hz时,焊缝截面凸起高度最小,侧壁熔深在两侧壁处宽度相72第2期 陈琪昊,等:厚壁铝合金摇动电弧窄间隙GMAW焊缝气孔分布与成形对均匀,焊缝成形良好;当摇动频率为0 5Hz的时候,侧壁熔深达到最大,但是焊缝成形不均匀,焊缝凸起高度较大.图10 摇动频率对侧壁熔深及凸起高度的影响Fig.10 Effectofswingfrequencyonsidewallpenetrationandhillheight摇动角度影响电弧的横向摇动宽度,对熔池金属的铺展有一定影响,从而影响到焊缝的侧壁熔深,因此,需要对摇动角度的影响规律进行研究.在这组试验当中,保持保护气体流速、焊接电流、焊接速度、摆动频率和侧壁停留时间试验工艺参数不变.摇动角度为导电嘴从坡口中心到侧壁之间的角度,不同摇动角度下的焊缝截面形貌如图6.发现当摇动角度为30°时,焊缝截面中部凸起高度最小,焊缝成形均匀,对称性较好.通过测量得出不同摇动角度下的焊缝截面凸起高度值和侧壁熔深值,如图11.焊缝截面凸起高度及侧壁熔深同样随摇动角度θ的增大先减小后增大.当摇动角度为30°的时候,焊缝截面凸起高度最小,截面凸起高度为0 91mm,侧壁熔深在两侧壁处宽度相对均匀,焊缝成形美观;而当摇动角度为32°的时候,侧壁熔深最大,侧壁熔深为3 31mm,但是焊缝成形不均匀,焊缝凸起高度达到最大.图11 电弧摇动角度对侧壁熔深及凸起高度的影响Fig.11 Effectofswingangleonsidewallpenetrationandhillheight改变侧壁停留时间,分别为40、100、120、160ms,不同侧壁停留时间下的焊缝宏观成形如图8.当侧壁停留时间为40ms时,焊缝凸起高度较小,侧壁熔合较均匀,焊缝成形较好.不同侧壁停留时间下的焊缝截面凸起高度值和侧壁熔深值如图12.图12 电弧侧壁停留时间对侧壁熔深及凸起高度的影响Fig.12 Effectofsidewalldwelltimeonsidewallpenetrationandhillheight焊缝截面凸起高度值和侧壁熔深值随侧壁停留时间的增大先增大后减小.当侧壁停留时间为100ms时,焊缝截面凸起高度最大,为2 4mm,侧壁熔深为2 75mm,侧壁熔深较小,焊缝凸起高度最大,焊缝成形差.侧壁停留时间为40ms时焊缝成形质量较好.当侧壁停留时间为120ms时,焊缝截面凸起高度为1 93mm,侧壁熔深最大,为3 01mm,焊缝右侧严重下凹,进行下一道焊缝焊接时可能会出现咬边的现象,焊缝成形较差.当侧壁停留时间为160ms的时候,侧壁熔深最小,焊缝截面分布不均匀,呈现左高右低的现象.2 3 焊缝气孔分布与焊缝成形之间的对应关系(1)摇动角度的影响摇动角度增大会使侧壁熔深增大,气孔率先减小后增大.摇动角度增大,能量密度分布发生变化,电弧接触到侧壁的面积增大,焊缝中心热量向侧壁扩散,导致侧壁金属熔化量增多.熔池金属在表面张力及电磁力的作用下开始向侧壁铺展,在熔池流动的作用下,侧壁附近的气泡更容易从熔池内逸出,熔池冷却凝固后,焊缝表面凸起高度降低,侧壁熔深增加.摇动角度继续增加,当电弧在侧壁停留时更加偏离焊缝中心,使焊缝中心的热输入量减小,熔滴滴入后不能在熔池内快速平铺,导致熔池中心液面较高,阻碍气泡逸出,气泡上浮时长大合并,过多大尺寸气泡滞留在焊缝中,熔池凝固后,焊缝气孔率随之上升,焊缝凸起高度增大,侧壁熔深增大.(2)摇动频率的影响摇动频率增大会使侧壁熔深、凸起高度及气孔率先减小后增大.当摇动频率变大,焊丝摇至侧壁的次数增多,对侧壁的热输入量增加.当摇动频率在一定范围内增加时,焊缝凸起高度下降.高的摇动频率通过影响熔滴冲击位置影响熔池流动形式,进而会影响熔池内气泡的溢出[8],气孔率下降.随着摇动频率继续增加,当频率过大时,电弧82江苏科技大学学报(自然科学版)2021年及焊丝摇动频率过大,导致电弧及熔滴过渡不稳定,热输入不均匀,导致焊缝中部熔池金属未来得及铺展就已凝固,焊缝凸起高度变大.熔池流动性变差,不利于气泡逸出,造成大量气泡滞留在焊缝中形成气孔.气泡在上浮中气泡长大合并,在焊缝上部分形成大量大尺寸气孔.(3)侧壁停留时间的影响侧壁停留时间增加会使侧壁熔深及凸起高度先增大后减小,气孔率先减小后增大.侧壁停留时间增加,电弧在侧壁的作用时间增加,侧壁受到的热量增加,侧壁金属熔化量增加,侧壁熔深增加;同时,焊丝在焊缝中间部分停留的时间就减少,导致焊缝中间部分热输入量小,焊缝中间金属熔化量少,导致焊缝凸起高度增大.当侧壁停留时间的较大时,焊缝截面形状发生改变,熔池金属主要集中填充于侧壁附近,受侧壁附近晶粒结晶的阻碍[9],气泡没有足够时间上浮逸出焊缝表面,滞留在焊缝中形成气孔,导致气孔率逐渐增大.当侧壁停留时间超过一定值时,侧壁熔深及凸起高度减小,可能是坡口两侧不对称加热导致的平均效应.3 结论(1)电弧摇动焊接时下,焊缝气孔率和焊缝成形具有一定的联系,良好的焊缝成形对应着较低的气孔率.(2)摇动频率增大,侧壁熔深、焊缝凸起高度及气孔率先减小后增大;摇动角度增大,侧壁熔深增大,焊缝凸起高度及气孔率先减小后增大;侧壁停留时间增大,侧壁熔深及焊缝凸起高度先增大后减小,气孔率先减小后增大.当摇动频率为1Hz、摇动角度为30°且侧壁停留时间为40ms时,焊缝气孔率低且成形较好.(3)电弧摇动主要通过焊接热输入、电弧及熔滴过渡的稳定性的变化影响熔池流动以及气泡的逸出,最终影响焊缝成形及气孔分布.参考文献(References)[1] 吴圣川,唐涛,李正.高强铝合金焊接的研究进展[J].现代焊接,2011(2):5-8.WUShengchuan,TANGTao,LIZheng.Progressofthestudyontheweldingofhigh intensityaluminumalloy[J].ModernWeldingTechnology,2011(2):5-8.(inChinese)[2] 张中元,聂帅强,王龙,等.窄间隙埋弧焊在厚钢板拼接焊中的工艺研究[J].新技术新工艺,2019(9):31-33.DOI:10.16635/j.cnki.1003-5311.2019.09.008.ZHANGZhongyuan,NIEShuaiqiang,WANGLong,etal.Researchonnarrow gapsubmergedarcweldinginprocessofthicksteelplatesplicing[J].NewTechnology&NewProcess,2019(9):31-33.DOI:10.16635/j.cnki.1003-5311.2019.09.008.(inChinese)[3] JapanWeldingSociety.Narrowgapwelding[M].To kyo:KurokiPress,1986.[4] 张富巨,罗传红.窄间隙焊及其新进展[J].焊接技术,2000,29(6):33-36.ZHANGFuju,LUOChuanhong.Narrowgapweldinganditsnewdevelopment[J].WeldingTechnology,2000,29(6):33-36.(inChinese)[5] 姚舜,钱伟方,秦笑梅.窄间隙熔化极气体保护焊技术研究[J].焊接技术,2002,31(12):43-45.DOI:10.3969/j.issn.1002-025X.2002.z1.017.YAOShun,QIANWeifang,QINXiaomei.Studyongasshieldedweldingofnarrowgapmeltingelectrode[J].WeldingTechnology,2002,31(12):43-45.DOI:10.3969/j.issn.1002-025X.2002.z1.017.(inChinese)[6] 黎文航,王加友,杨峰,等.窄间隙焊缝跟踪旋转电弧电流平均值传感法比较研究[J].江苏科技大学学报(自然科学版),2009,23(3):209-212.DOI:10.3969/j.issn.1673-4807.2009.03.006.LIWenhang,WANGJiayou,YANGFeng,etal.Researchonarcsensingmethodofveragecurrentfornarrowgaprotatingmethod[J].JournalofJiangsuUniversityofScienceandTechnology(NaturalScienceEdition),2009,23(3):209-212.DOI:10.3969/j.issn.1673-4807.2009.03.006.(inChinese)[7] 徐望辉,林三宝,杨春利,等.摆动电弧窄间隙立向上GMAW焊缝成形[J].焊接学报,2015,36(4):56-60.XUWanghui,LINSanbao,YANGChunli,etal.WeldbeadformationinoscillatingarcnarrowgapverticalupGMAWprocess[J].TransactionsofTheChinaWeldingInstitution,2015,36(4):56-60.(inChinese)[8] ZHUCX,CHEONJ,TANGXH,etal.Effectofswingarconmoltenpoolbehaviorsinnarrow gapGMAWof5083Al alloy[J].JournalofMaterProcessTechnology,2018(259):243-258.DOI:10.1016/j.jmatprotec.2018.04.026.[9] ZHUCX,TANGXH,HEY,etal.CharacteristicsandformationmechanismofsidewallporesinNGGMAWof5083Al alloy[J].JournalofMaterProcessTechnology,2016(238):274-283.DOI:10.1016/j.jmatprotec.2018.04.026.(责任编辑:贡洪殿)92第2期 陈琪昊,等:厚壁铝合金摇动电弧窄间隙GMAW焊缝气孔分布与成形。

Biodegradable Packaging Materials

Biodegradable Packaging Materials

Biodegradable Packaging MaterialsBiodegradable packaging materials have become a popular topic of discussion in recent years, as the world grapples with the environmental impact of plastic pollution. With the increasing awareness of the detrimental effects of non-biodegradable packaging on the environment, there is a growing demand for sustainable alternatives. In this response, we will explore the importance of biodegradable packaging materials, the benefits and challenges associated with their use, and the potential impact on businesses and consumers.First and foremost, it is crucial to understand the significance of biodegradable packaging materials in addressing the global issue of plastic pollution. Non-biodegradable plastics take hundreds of years to decompose, leading to the accumulation of waste in landfills, oceans, and other natural habitats. This not only poses a threat to wildlife and ecosystems but also contributes to the release of harmful toxins into the environment. Biodegradable packaging materials, on the other hand, are designed to break down naturally over time, reducing the long-term environmental impact of packaging waste. By embracing biodegradable alternatives, we can minimize our reliance on non-renewable resources and mitigate the ecological harm caused by traditional packaging materials.In addition to their environmental benefits, biodegradable packaging materials offer a range of advantages for businesses and consumers. For businesses, the use of biodegradable packaging can enhance their corporate social responsibility efforts and improve their brand image. With consumers becoming increasingly eco-conscious, companies that demonstrate a commitment to sustainability are likely to attract and retain customers who prioritize environmental stewardship. Moreover, biodegradable packaging materials can help businesses comply with evolving regulations and standards related to environmental protection. From a consumer perspective, biodegradable packaging provides a sense of reassurance that their purchasing choices align with their values and contribute to environmental conservation. By opting for products with biodegradable packaging, consumers can feel empowered in their role as environmentally responsible individuals.Despite the numerous benefits of biodegradable packaging materials, there are also challenges and considerations that warrant attention. One of the primary concerns is thecost associated with transitioning to biodegradable alternatives. While the prices of biodegradable materials have been decreasing as technology advances and demand increases, they still tend to be more expensive than traditional plastics. This cost disparity can present a barrier for businesses, especially small and medium-sized enterprises, that are operating within tight budget constraints. Additionally, there may be limitations in the availability and variety of biodegradable packaging options, which could pose logistical challenges for businesses seeking to adopt these materials. Furthermore, the performance and shelf life of biodegradable packaging materials need to be carefully evaluated to ensure that they meet the necessary durability and functionality requirements.In light of these considerations, it is essential for businesses to weigh the trade-offs and make informed decisions regarding the adoption of biodegradable packaging materials. While the initial investment and operational adjustments may present challenges, the long-term benefits of embracing sustainable packaging solutions are undeniable. By prioritizing environmental responsibility and aligning with consumer preferences, businesses can position themselves as leaders in sustainability and contribute to the global effort to reduce plastic waste. Moreover, as the demand for biodegradable packaging materials continues to grow, it is likely that innovations and advancements in this field will lead to more cost-effective and diverse options, further facilitating the transition towards sustainable packaging practices.In conclusion, the adoption of biodegradable packaging materials is a pivotal step towards mitigating the environmental impact of plastic waste and promoting sustainable business practices. By recognizing the significance of biodegradable alternatives, businesses can align with consumer values, enhance their brand reputation, and contribute to the preservation of the planet. While there are challenges to overcome, the long-term benefits of embracing biodegradable packaging materials far outweigh the initial obstacles. As we collectively strive towards a greener and more sustainable future, the widespread adoption of biodegradable packaging materials holds immense promise for businesses, consumers, and the environment alike.。

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Effect of Pore Packing Defects in2-D Ordered Mesoporous Carbons on Ionic TransportDa-Wei Wang,†Feng Li,†Hai-Tao Fang,†,‡Min Liu,†Gao-Qing Lu,§and Hui-Ming Cheng*,†Shenyang National Laboratory for Materials Science,Institute of Metal Research,Chinese Academy ofSciences,72Wenhua Road,Shenyang110016,China,Materials Science and Engineering School,HarbinInstitute of Technology,92West Dazhi Street,Harbin150001,China,and Australian Research Council Centrefor Functional Nanomaterials,School of Engineering,The Uni V ersity of Queensland,QLD4072,AustraliaRecei V ed:December13,2005;In Final Form:March12,2006Ordered mesoporous materials show great importance in energy,environmental,and chemical engineering.The diffusion of guest species in mesoporous networks plays an important role in these applications,especiallyfor energy storage,such as supercapacitors based on ordered mesoporous carbons(OMCs).The ion diffusionbehavior in two different2-D hexagonal OMCs was investigated by using cyclic voltametry and electrochemicalimpedance spectroscopy.In addition,transmission electron microscopy,small-angle X-ray diffraction,andnitrogen cryosorption methods were used to study the pore structure variations of these two OMCs.It wasfound that,for the OMC with defective pore channels(termed as pore packing defects),the gravimetriccapacitance was greatly decayed when the voltage scan rate was increased.The experimental results suggestthat,for the ion diffusion in2-D hexagonal OMCs with similar mesopore size distribution,the pore packingdefect is a dominant dynamic factor.1.IntroductionOrdered mesoporous materials have shown great potential in many important applications,such as chemical catalysis, environmental separation,and energy storage.1-3All these applications involve the transportation of guest species(gas/ liquid)in the mesoporous networks.Therefore,it is extremely vital to understand the effect of ordered mesopores on the dynamic processes of these guest species with respect to design of new ordered mesoporous structures.Electrical double layer capacitors(EDLCs),in which the electrical energy storage/release depends on ion transport in the framework composed of nanometer-sized pores(mainly meso-pores),have been considered as a promising energy storage device in many fields.2-5,8-12Understanding the influence of different mesoporous materials(ordered or disordered arrange-ment)on ion diffusion behavior is fundamental to enhancing EDLC’s performance.However,in the past,the diverse and uncontrollable intrinsic microporous structure of physically or chemically activated carbons has made it impossible to precisely investigate the relations between mesoporous textures and ion diffusion behavior.Recently,Ryoo and co-workers have synthesized ordered mesoporous carbons(OMCs).6,7These OMCs,with mesopore size tailorable and regularly intercon-nected mesoporous channels,are considered to be very promis-ing materials for investigating the impact of ordered mesopores on ion diffusion behavior,which determines the energy density of EDLCs under large current operations.A few groups have studied the impact of ordered mesopores on ion diffusion behavior by evaluating the performance of EDLCs based on OMCs.8-12Their experiments show that2-D hexagonal OMCs exhibit better EDL capacitive performance than3-D cubic OMCs,which is believed to be attributed to the favorable ion diffusion in larger mesopores existing in2-D hexagonal OMCs.8,9,12Nevertheless,it is clear that only one-dimension diffusion is available in2-D hexagonal OMCs.It can be assumed that if the single diffusion direction is blocked, no other diffusion routes will be available.Consequently,it is quite important to understand to what extent the blockage of the single diffusion direction will influence the ion diffusion ability of2-D hexagonal OMCs.A simple method was developed in this paper to control the blockage conditions in2-D hexagonal OMCs.The capacitance-decaying trends of two different2-D OMCs were investigated by cyclic voltammogram(CV)at different voltage sweep rates. Moreover,electrochemical impedance spectroscopy(EIS),which is a powerful method for obtaining information on the dynamic ion diffusion behavior,13-16has been utilized to evaluate the influence of blockage conditions on the ion diffusion behavior in2-D hexagonal bined with mesopore structure characterizations,the present results clearly demonstrate that defective2-D ordered mesoporous channels dramatically reduce the ion diffusivity in mesopores.2.Experimental Section2.1.Synthesis and Characterization of OMCs.The2-D hexagonal OMCs materials were obtained by a templating procedure for which ordered mesoporous silica SBA-15was chosen as a template.The SBA-15templates were prepared according to the method described by Jun et al.7However,the final calcination process,which is used to remove the surfactant embedded in SBA-15,was altered to adjust the remaining surfactant amount.For Condition1,the silica template was calcined in an oxygen-poor atmosphere and dark brown powder was obtained;for Condition2,the silica template was calcined in an oxygen-rich atmosphere yielding pure white powder.The oxygen-poor atmosphere was realized simply by air-proofing the volume-limited oven tube,because the available oxygen*Address correspondence to this author.E-mail:cheng@.Fax:86-24-2390-3126.†Chinese Academy of Sciences.‡Harbin Institute of Technology.§The University of Queensland.8570J.Phys.Chem.B2006,110,8570-857510.1021/jp0572683CCC:$33.50©2006American Chemical SocietyPublished on Web04/08/2006amount in the volume-limited oven tube was exhausted during calcination.The oxygen-rich atmosphere was realized by controlling the inner pressure of the oven tube to be about double that of the atmospheric pressure under a flowing air stream. The effect of oxygen-poor atmosphere was to remove the surfactant in primary mesopores of the silica template,while keeping the surfactant in secondary mesopores.In the case of an oxygen-rich atmosphere,the surfactant in both primary and secondary mesoproes was removed.OMCs were hence synthesized by first templating the pretreated SBA-15with sucrose as carbon precursor and then carbonizing by a prescribed heating procedure in argon atmo-sphere.7The resultant silica/carbon composites were washed with NaOH dissolved in a deionized water/ethanol(volume ratio 1:1)(0.1M)solution at373K for3h to remove the silica template.The remaining carbon was then filtered and rinsed until the pH was7.Thereafter,the wet powder was dried under vacuum at373K for12h.The resultant carbon powders were denoted as CS-1and CS-2to differentiate the respective calcination conditions of the corresponding SBA-15templates. The OMCs were characterized by TEM(JEOL2010,200 kV).The OMCs samples were mixed in absolute ethanol and ultrasonically dispersed for several seconds.Then,the dispersed homogeneous solution was dropped onto a microgrid and driedfor TEM observations.The small-angle X-ray diffraction (SAXRD)patterns were collected with use of an RINT2200 (Cu K R,λ)1.5406Å)at a step scan rate of0.02°from1.5°to10°.Nitrogen cryosorption was conducted on a Micrometrics ASAP2010M;before measurements,all the OMC samples were evacuated at473K until the manifold pressure was lower than 2Pa.The external surface specific surface area(SSA)is the difference between BET specific surface area(BET-SSA)and micropore surface SSA.The BET-SSA was calculated based on the BET method.The micropore surface SSA was calculated based on the t-plot method.All these calculations were accomplished with the software provided along with the ASAP2010M instrument.2.2.Electrochemical Measurements.The electrochemical measurements were carried out in a three-electrode system. Nickel foam covered with a composite of activated carbon powders and poly(tetrafluoroethylene)(PTFE)was used as counter electrode(CE).Hg/HgO was chosen as reference electrode(RE)in an alkaline electrolyte of6M KOH.The preparation of the working electrode(WE)for the three-electrode system was as follows.The active materials,CS-1 and CS-2,5.5mg each,were mixed with1mg of PTFE in absolute ethanol and spread onto nickel foam with a size of10 mm×10mm,respectively.Then,the nickel foam covered with 5.5mg of active materials was used as the WE.The electrolyte was6M KOH aqueous solution.The cyclic voltammogram and electrochemical impedance spectroscope were collected on Solartron1287/1260electrochemical systems.The potential range for CV was-1to0V vs Hg/HgO.The bias potential applied to the electrode during EIS was0V vs Hg/HgO,the frequency range was10mHz to100kHz,and the AC signal amplitude was10mV.3.Results and Discussion3.1.Pore Structure Characterization of OMCs.The TEM images of CS-1and CS-2perpendicular to their pore channels are illustrated in Figure1a-d.It can be seen that the pore channels of CS-1were far from parallel and straight compared to those of CS-2.During the TEM observations,it was found that most of the CS-1samples possessed similar defective pore structure.In fact,sections2and3(2and3in Figure1a)indeed possess more defective pore structure than section1(1in Figure 1a)because of the absence of distinct localized regular pore structure.However,considering the easy identification of defective pore structure,we chose to show the HRTEM of section1(1in Figure1a)to provide a distinct comparison between the regular pore structure and the defective pore structure,as observed in pared with the straight parallel mesopore channels in Figure1d,the mesopores in Figure 1b comprise a large number of randomly distributed defective sites.The irregular defective sites in the mesopore channels mainly include(i)collapse of the primary mesopores and(ii) blockage of the primary mesopores.It is accepted that the ordered hexagonal mesoporous framework composed of primary carbon rods in2-D OMCs is supported by many smaller secondary carbon nanorods7,12and obviously the absence of these short nanorods would cause an irregularly collapsed primary mesopore texture,as in the case of CS-1,which results from the unstable packing conditions of mesopore channels.The detailed formation mechanism of the irregularly collapsed mesopore channels of CS-1can be explained as follows.As mentioned above,the SBA-15template used for the preparation of CS-1was calcined in an oxygen-poor atmosphere and showed a dark brown color after calcina-tion,indicating incomplete removal of the surfactant,and the content of the carbon residue from surfactant was determined to be6wt%by TG in air up to1273K,shown in Figure1S (see the Supporting Information).It is important to mention that both SBA-15templates possessed similar primary mesopore sizes,which probably resulted from complete removal of surfactant existing in the primary mesopores.Hence,the brown-looking carbon residue from surfactant must exist in the smaller secondary mesopores inside the silica walls.Consequently, during the preparation of CS-1,a large number of smaller inner-wall mesopores could not be impregnated by sucrose molecules due to the blockage by the carbon residue from surfactant.That condition would have led to a shortage of smaller secondary carbon nanorods to support the ordered mesoporous structure of resultant OMCs,and hence resulted in the irregular collapsing defects observed in the TEM images.Furthermore,thecarbon Figure1.Typical TEM images of2-D hexagonal OMCs:(a,b)CS-1;(c,d)CS-2.Panels b and d are the HRTEM images of the corresponding square areas in panels a and c,respectively;the white arrows in panel b show the pore packing defects in mesopore textures; the dark arrows in panel d show regularly packed mesopores;white arrow1points out the collapsed mesoporous channels and white arrow 2points out the blockage of mesopore channels by carbon residue from surfactant.Effect of Pore Packing Defects on Ionic Transport J.Phys.Chem.B,Vol.110,No.17,20068571residue from surfactant also blocked the mesopore channels of CS-1after the silica template was dissolved,as shown in Figure 1b by the arrows.Because the formation of mesopore channels resulted from the package of primary carbon rods,and the defective packing conditions of mesopore channels (including the collapse of primary carbon rods and blockage of primary mesopores by carbon residue from surfactant)gave rise to these defective sites,it is reasonable to define these defects as pore packing defects (PPDs).Figure 2shows the SAXRD patterns of CS-1and CS-2.It can be seen that CS-1possessed a low degree of periodic order with a weak intensity from (110)planes.CS-2exhibited a high degree of periodic order with a strong intensity from both (110)and (200)planes.The visible high index peak (200)indicates a high periodic order in the arrangement of symmetry cells (here the symmetry cell is the carbon cylinder).6,7It can be deduced,then,that the low degree of arrangement order in CS-1resulted from pore packing defects in the hexagonal carbon honeycomb structure,in agreement with the TEM observations.7The nitrogen adsorption -desorption isotherms,which are shown in Figure 3a,are used to determine the specific surface area (SSA)and pore size distribution (PSD)of the OMCs.The isotherms for CS-1and CS-2are typical Type IV isotherms and show an obvious capillary condensation step (hysteresis loop),as is characteristic of OMCs.7However,the capillary-condensation relative pressure ranges (P /P 0)for CS-1and CS-2are different.The pressure range for CS-1is 0.5to 0.7,which is higher than that of CS-2(0.4to 0.6).This result corresponds to the existence of larger mesopores in CS-1(5.5nm)than in CS-2(4.8nm)based on Density Functional Theory (DFT)analysis,as shown in Figure 3b.The BET-SSA and external surface SSA are listed in Table 1.From the nitrogen isotherms,the external surface area is mainly composed of mesopore surface area,and the ratio of macropores is quite small.On the basis of the data in Table 1,it can be seen that although CS-2has a higher BET surface area,the percentage of mesopores is quite close to that of CS-1.Therefore,the pore structure deviations between CS-1and CS-2are mainly (1)CS-1possesses a defective mesoporous structure with lower periodicorder compared with that of the regular mesoporous channels of CS-2and (2)CS-1has a larger mesopore size than that of CS-2.3.2.Electrochemical Performance of OMCs.The influence of ordered mesoporous structure on ion transport bahavior can be characterized by the CV method based on the evaluation of capacitive performance of EDLC based on OMCs.8-12Gener-ally,the desired capacitive performance requires a rectangular shaped voltammogram.Besides,the capacitive behavior can also be studied by changing the voltage sweep rates to estimate the applicability for quick charge -discharge operations.12The cyclic voltammograms of CS-1and CS-2are presented in Figure 4,panels a and b,respectively,for different voltage scan rates.The voltammograms of these two carbons maintained the desired rectangular shape at voltage scan rates of 5mV/s,where the charging and discharging curves were parallel with the voltage axis.When the voltage scan rate was increased to 50mV/s,a quasirectangular shape can still remain for CS-2,indicating excellent capacitive behavior even at high current intensity.However,the voltammogram of CS-1exhibited a triangular shape at 50mV/s,indicating the absence of capacitive behavior at high current density.This means that CS-1would be less suitable for quick charge -discharge operations than CS-2.The absolute gravimetric capacitance and specific surface capacitance (capacitance per unit surface area)are listed in Tables 2and 3,respectively.From Table 3,it can be seen that CS-1has higher specific surface capacitance than CS-2.This probably comes from the superior active surface of CS-1,as suggested by DSC results shown in Figure 2S (see the Supporting Information).As the voltage scan rates increased,the difference of gravimetric capacitance and specific surface capacitance between CS-1and CS-2decreased.The same trend was also observed from the results in a two-electrode system,as shown in Tables 1S and 2S (see the Supporting Information).This probably originates from the absence of capacitive behavior of CS-1at high current density.To evaluate the capacitive behavior of CS-1and CS-2,the ratio of retained gravimetric capacitance vs increased voltage scan rates is plotted in Figure 5.CS-2maintains 82%of its capacitance at a high voltage scan rate of 50mV/s,which is more than the ratio of 74%for CS-1.These unexpected results show a better capacitive behavior for CS-2despite its smaller mesopore size than that of CS-1.Generally,the faster the penetration of electrolyte ions into electrochemically active porous surface,the better the capacitive behavior at high voltage scan paring CS-1with CS-2,the inferior capacitive behavior of CS-1is unexpected because of its relatively larger mesopore size.However,as mentioned previously,the pore channel packing defects (PPDs)in CS-1are much different from those in CS-2.To account for the larger mesopore size and inferior capacitive behavior for CS-1,it is believed that the different PPDs for CS-1and CS-2must have played a dominant role in determining the capacitive behavior at high voltage scan rates.3.3.Electrochemical Impedance Spectroscopy of OMCs.Although the CV method can be utilized to estimate the ion transport behavior in ordered mesoporous structure byvaryingFigure 2.Small angle XRD patterns of CS-1andCS-2.Figure 3.(a)Nitrogen cryosorption isotherms and (b)DFT pore size distributions of CS-1and CS-2.TABLE 1:Specific Surface Area and Pore Diameter of CS-1and CS-2carbon S BET (m 2/g)S ext (m 2/g)apore diameter (nm)bCS-11089822 5.5CS-212229044.8aSpecific surface area of the external surface,calculated from the t-plot method.b Peak value of the mesopore diameter distribution curves based on the DFT method.8572J.Phys.Chem.B,Vol.110,No.17,2006Wang et al.the voltage sweep rates,it is still unable to precisely describe the actual electrochemical diffusion process.Hence,it is quite important to further investigate the influence of ordered meso-porous structure on ion diffusion based on EIS,which has been considered as a powerful method to obtain dynamic ion diffusion information.13-16The formation of EDL capacitance under an alternative electric field for a mesoporous/microporous electrode should involve three processes:(a)a high-frequency region where mass transfer is inhibited,so charge aggregation at the surface of carbon powder electrode in contact with the bulk electrolyte would be dominant;(b)a medium-frequency region where the dominant process would be ion diffusion in mesoporous channels which contributes the most to the development of capacitive behavior;and (c)a low-frequency region where inhomogeneous diffusion in the less-accessible sites (likemicropores)may govern the impedance.13Thus,the inferior dynamic capacitive performance of CS-1at high voltage scan rates ought to be related to the ion diffusion ability in mesoporous channels which is identified as the medium-frequency region in both Nyquist and Bode plots.The complex -plane impedance plots (Nyquist plots)for CS-1and CS-2are given in Figure 6a.The knee frequencies are illustrated in the inset of Figure 6a,and the values for CS-1and CS-2are 39.8and 63.1Hz,respectively.Generally,the knee frequency is considered to be the critical frequency where EDLC begins to exhibit capacitive behavior.In the impedance plots,when the frequency is less than the knee frequency,a straight line,nearly vertical to the realistic impedance axis (Z ′),was observed,characteristic of an admirable capacitive behavior.Deviation from the vertical line is attributable to inner-mesopore diffusion resistance for electrolyte ions,which is strongly dependent on the detailed mesoporous structure of the different samples.Therefore,it is possible to investigate the dynamic process of ion diffusion in ordered mesopores based on EIS.In the phase angle plot,the approach to pure capacitive behavior at low frequency is usually identified with phase angle approaching to the negative 90degree.14Accordingly,the value of the phase angle can be used to evaluate the effectiveness of ion diffusion in mesopores at the medium-frequency region.That is,the smaller the phase angle,the better the capacitive performance and,hence,the faster the ions diffuse.The frequency dependent behaviors of the phase angle,Φ,are illustrated in Figure 6b (Bode plots).When the frequency is lower than 1.6Hz,where the impedance behavior of both CS-1and CS-2would be ion-diffusion controlled,the phase angle of CS-2is always smaller than that of CS-1.This result indicates more rapid diffusion of ions in the ordered mesoporous channels of CS-2,regardless of its smaller mesopore size than thatofFigure 4.Cyclic voltammograms for (a)CS-1and (b)CS-2in 6M KOH at different voltage scan rates.TABLE 2:The Gravimetric Capacitance of CS-1and CS-2under Different Measurement Conditions in a Three-Electrode Systemgravimetric capacitance at different voltage scan rates (F/g)capacitor type sample 5mV/s 10mV/s 20mV/s 30mV/s 40mV/s 50mV/s 3-electrodeCS-1122.5109.7102.796.995.790.4CS-299.594.589.686.183.881.5TABLE 3:The Specific Surface Capacitance of CS-1and CS-2under Different Measurement Conditions in a Three-Electrode Systemspecific surface capacitance at different voltage scan rates (F/m 2)acapacitor type sample 5mV/s 10mV/s 20mV/s 30mV/s 40mV/s 50mV/s 3-electrodeCS-10.1120.10.0940.0890.0880.083CS-20.0810.0770.0730.070.0690.067aThe specific surface capacitance (C s )was calculated by the equation C s )C g /S BET ,where C g is the gravimetric capacitance listed in Table 2and S BET is the BET specific surface area listed in Table1.Figure 5.The retained capacitance change of CS-1and CS-2with voltage scan rates.Effect of Pore Packing Defects on Ionic Transport J.Phys.Chem.B,Vol.110,No.17,20068573CS-1.Therefore,CS-2shows a closer approach to pure capacitive behavior,which means that the ions are able to access more electrochemically active mesoporous surfaces in CS-2than in CS-1at the same AC frequency in the medium region.3.4.Impact of Pore Packing Defects on Ion Transport.Both the CV and EIS methods clearly demonstrate that CS-2exhibits a superior capacitive performance to CS-1,which means that the mesoporous structure of CS-2favors ion diffusion.To account for the inferior mesopore size of CS-2to that of CS-1,the intense negative impact of PPDs on ion diffusion must be clarified.Impedance behavior on porous electrodes can be understood by ion penetrability:at higher penetrability most of the electrode surface should be detected,while at lower penetrability,only part of the porous electrode surface would be detected.15On this basis,CS-2should possess a higher penetrability than CS-1does,as discussed previously.The ion penetrability R can be expressed by the following formula:16where r is the pore radius,l p is the pore length,R is the inner-pore electrolyte resistance,C d is the specific surface EDL capacitance at the interface between the carbon phase and the electrolytes,and ωis the angular frequency.It can be seen that the value of penetrability is directly proportional to r 1/2,l p -1,and R -1/2.As the mesopore diameter for CS-1is 5.5nm,larger than that of CS-2,the values of l p -1and R -1/2for CS-1should be much smaller than those of CS-2,which would,in turn,give a lower penetrability value for CS-1in order to be consistent with its poor capacitive behavior as determined by CV and EIS.As observed from TEM images,the morphology of 2-D OMCs was rodlike particles with length at the micrometer scale and the primary mesopores running through the OMC rods.Therefore,it should be possible to estimate the primary mesopore length by evaluating the OMC rod length.From the OMC rod length distribution illustrated in Figure 7,CS-1and CS-2possess a similar rod length distribution with their peak values located between 0.8and 1.2µm,which indicates a similar primary mesopore length and hence a similar l p -1value for both CS-1and CS-2.It has been deduced that the penetrability for CS-1could be smaller than that for CS-2only in the case of a smaller value of l p -1and R -1/2for CS-1than for CS-2.However,the l p -1value has been proved to be similar for both CS-1and CS-2.Consequently,the value of R -1/2for CS-1must be greatly smaller than that for CS-2.As a result,the electrolyte ion resistance,R ,in the mesoporous channels of CS-1must be much larger than that of CS-2.The large ion diffusion resistance R must have had a serious negative effect on reducing the ion diffusion ability,which,in turn,would have lowered the ion penetrability for CS-1.As determined by TEM and SAXRD,CS-1is believed to have possessed much more pore packing defects than CS-2.In other words,the PPDs for CS-1are greater than that for CS-2and,hence,will contribute to a large inner-pore electrolyte resistance,as deducedabove.Figure 6.The Nyquist plots (a)and Bode plots (b)of CS-1andCS-2.Figure 7.Statistical length distributions of the OMC rod from SEM images:(a)CS-1and (b)CS-2(inset figures are the corresponding SEM images for CS-1and CS-2,respectively).R )12l pr Cd ωR(1)8574J.Phys.Chem.B,Vol.110,No.17,2006Wang et al.When electrolyte ions transport into a pore under the stimulation of an AC signal,the ions will penetrate deeper along the porous channel with decreasing frequency until they have accessed the entire pore surface.14,15Unfortunately,ion diffusion is intensely dependent on the actual pore channel conditions rather than an ideally cylindrical pore without any defects.14,15 The distributed pore packing defects along the mesoporous channels will constrict the mesopores to some extent.When the PPDs are severe and lead to a confined effect on pore diameters,as pointed out by the arrows in Figure1b,the electrolyte ions will be restricted in the narrowed parts of the channels,and will transport more slowly than in the regular defect free mesopores(Figure1d).This phenomenon would certainly increase the transport resistance in the mesoporous channels and hence result in a decrement of the ion penetrability, as observed for CS-1.Therefore,the capacitive behavior of CS-1 at high voltage scan rates was inferior to that for CS-2. Evidently,for2-D hexagonal OMCs with similar PSD,the dynamic ion diffusion behavior in mesoporous channels will be strongly controlled by pore packing defects rather than by pore size distributions.4.ConclusionThe capacitive behaviors of two different2-D hexagonal OMCs were investigated based on CV and EIS.It was found that for an OMC with a larger mesopore size the capacitive behavior was inferior to that of an OMC with a smaller mesopore size.The reason is believed to lie in the difference between their ordered mesoporous structures.Pore packing defects have been proposed as the basis for interpreting these unexpected results.It is considered that for2-D OMCs with similar mesopore diameters,the pore packing defects will determine the ion diffusion process in ordered mesopores at high current intensity.It is believed that a defect-free stable ordered mesoporous system will enable the electrolyte ion to transport more efficiently and will ultimately enhance the total EDLC system performance.Acknowledgment.This work was supported by NFSC (50328204,50472084)and the Hi-Tech Research and Develop-ment Program of MOST(2004AA302090),ChinaSupporting Information Available:Electrochemcial mea-surement results in a two-electrode system and TG/DSC results, including the TG curves of silica templates(Figure1S),the DSC curves of OMCs(Figure2S),the gravimetric capacitance values in a two-electrode system(Table1S),and the specific surface capacitance values in a two-electrode system(Table2S). 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