Comprehensive evaluation of chemical breakers for multistage network ultra-high strength gel

Polymer gels have been accepted as a useful tool to address many sealing operations such as drilling and completion,well stimulation,wellbore integrity,water and gas shutoff,etc.Previously,we developed an ultra-high strength gel(USGel)for medium to ultra-low temperature reservoirs.However,the removal of USGel is a difficult problem for most temporary plugging operations.This paper first provides new insights into the mechanism of USGel,where multistage network structure and physical entanglement are the main reasons for USGel possessing ultra-high strength.Then the effects of acid breakers,encapsulated breakers,and oxidation breakers(including H_(2)O_(2),Na_(2)S_(2)O_(8),Ca(ClO)_(2),H_(2)O_(2)+NaOH,Na_(2)S_(2)O_(8)+NaOH,and Ca(ClO)_(2)+NaOH)were evaluated.The effects of component concentration and temperature on the breaking solution were studied,and the corrosion performance,physical simulation and formation damage tests of the breaking solution were carried out.The final formulation of 2%-4%NaOH+4.5%-6%H_(2)O_(2) breaking solution was determined,which can make USGel completely turn into water at 35e105C.The combinations of“acid t breaking solution”,“acid+encapsulated breaker”and“encapsulated breaker+breaking solution”were evaluated for breaking effect.The acid gradually reduced the volume of USGel,which increased the contact area between breaking solution and USGel,and the effect of“4%acid+breaking solution”was 23 times higher than that of breaking solution alone at 35C.However,the acid significantly reduced the strength of USGel.This paper provides new insights into the breaking of high-strength gels with complex network structures.

The Adsorption of Pb(II)Using Silica Gel Synthesized from Chemical Bottle Waste:Optimization Using Box-Behnken Design

The adsorption of Pb(II)on silica gel synthesized from chemical glass bottle waste has been studied.The effect of independent variables(adsorbent dose,initial concentration of Pb(II),contact time,and pH)on the Pb(II)removal from water was evaluated and optimized using the Response Surface Methodology(RSM).Under optimized conditions(adsorbent dose:20 mg;contact time:30 min;initial Pb(II)concentration:120 mg.L^(−1);and pH:8),the removal of Pb(II)was 99.77%.The adsorption equilibrium data obtained from the batch experiment were investigated using different isotherm models.The Langmuir isotherm model fits the experimental data.This shows that the surface of the silica gel synthesized from chemical bottles waste was covered by a Pb(II)monolayer.XRF analysis showed that the synthesized silica gel had a SiO_(2) content of 75.63%.Amorphous silica was observed from XRD analysis.SEM-EDX characterization showed that Pb was adsorbed on the silica gel surface.SEM analysis showed that silica gel has irregular particles with a surface area of 297.08 m2.g^(−1) with a pore radius of 15.74 nm calculated from BET analysis.

CHEMICAL MODIFICATION OF THE SURFACE OF CALCIUM ALGINATE GEL BEADS

The chemical modification of the surface of calcium alginate gel beads (CAGB) via grafting copolymerization with vinyl acetate (VAc) was studied. The optimum reaction conditions with activation and graft copolymerization two steps were explored. First, 5 grams CAGB with 2.5 mm initial diameter was initiated with 0.0493 mol/L K2S2O8 at 51 °C for 30 min in 15 mL 1 % PVA/H2O. Then 4.34 moi/L VAc was added dropwise and the reaction was allowed to proce at 48 °C for 3 h. The grafting efficiency could come up to 30%. It was found the stability of modified CAGB in the air and in electrolyte solutions was greatly improved.

Gel-Based Chemical Cross-Linking Analysis of 20S Proteasome Subunit-Subunit Interactions in Breast Cancer

The ubiquitin-proteasome system plays a pivotal role in breast tumorigenesis by controlling transcription factors, thus promoting cell cycle growth, and degradation of tumor suppressor proteins. However, breast cancer patients have failed to benefit from proteasome inhibitor treatment partially due to proteasome heterogeneity, which is poorly understood in malignant breast neoplasm. Chemical crosslinking is an increasingly important tool for mapping protein three-dimensional structures and proteinprotein interactions. In the present study, two cross-linkers, bis（sulfosuccinimidyl） suberate（BS3） and its water-insoluble analog disuccinimidyl suberate（DSS）, were used to map the subunit-subunit interactions in 20 S proteasome core particle（CP） from MDA-MB-231 cells. Different types of gel electrophoresis technologies were used. In combination with chemical cross-linking and mass spectrometry, we applied these gel electrophoresis technologies to the study of the noncovalent interactions among 20 S proteasome subunits. Firstly, the CP subunit isoforms were profiled. Subsequently, using native/SDSPAGE, it was observed that 0.5 mmol/L BS^3 was a relatively optimal cross-linking concentration for CP subunit-subunit interaction study. 2-DE analysis of the cross-linked CP revealed that α1 might preinteract with α2, and α3 might pre-interact with α4. Moreover, there were different subtypes of α1α2 and α3α4 due to proteasome heterogeneity. There was no significant difference in cross-linking pattern for CP subunits between BS3 and DSS. Taken together, the gel-based characterization in combination with chemical cross-linking could serve as a tool for the study of subunit interactions within a multi-subunit protein complex. The heterogeneity of 20 S proteasome subunit observed in breast cancer cells may provide some key information for proteasome inhibition strategy.

Production of HfO_2 thin films using different methods: chemical bath deposition, SILAR and sol–gel process

Hafnium oxide thin films （HOTFs） were successfully deposited onto amorphous glasses using chemical bath deposition, successive ionic layer absorption and reaction （SILAR）, and sol-gel methods. The same reactive precursors were used for all of the methods, and all of the films were annealed at 300℃ in an oven （ambient conditions）. After this step, the optical and structural properties of the films produced by using the three different methods were compared. The structures of the films were analyzed by X-ray diffTaction （XRD）. The optical properties are investigated using the ultraviolet-visible （UV-VIS） spectroscopic technique. The film thickness was measured via atomic force microscopy （AFM） in the tapping mode. The surface properties and elemental ratios of the films were investigated and measured by scanning electron microscopy and energy-dispersive X-ray spectroscopy （EDX）. The lowest transmittance and the highest reflectance values were observed for the films produced using the SILAR method. In addition, the most intense characteristic XRD peak was observed in the diffraction pattern of the film produced using the SILAR method, and the greatest thickness and average grain size were calculated for the film produced using the SILAR method. The films produced using SILAR method contained fewer cracks than those produced using the other methods. In conclusion, the SILAR method was observed to be the best method for the production of HOTFs.

Fabrication of Chemically-Modified Electrode Containing 1:12 Phosphomolybdic Anions by Sol-Gel Technique and Its Electrocatalytic Reduction of BrO_3 ^-Anions

A novel chedrically-modified electrode containing 1:12 phosphomolybdic anions wasachieved on the surface of platinum electrode by the sol-gel technique. The electrode exhibits ahigh catalytic activity towards the electroreduction of BrO3- anions.

Development of Optical Chemical Sensor Based on Pararosaniline in Sol-Gel Matrix for Detection of Formaldehyde in Food Samples

Optical chemical sensor based on immobilesed pararosaniline into sol-gel matrix tetraethyl orthosilicate (TEOS) is a simple tool that can be used to detect the presence of formalin (formaldehide) in food. Pararosaline in sol-gel matrix was developed when contacted with food sample that contains formalin. The optical signal was produced by changing color from purple to yellow, that can be used to detect quantitative formaldehide in sample. The results, chemo sensor optic, have characteristic, maximum wave length 576.42 nm, with linier range 0-100 ppm, linearity coefficient R2 = 0.999, limit detection (LOD) 0.504 ppm, limit of quantification (LOQ) 1.680 ppm, sensitivity 0.087, disturbed matrix selectivity 1.716 %. The optimum is operational at pH 4, and response time at 150 seconds of 2 ppm. This sensor can be used to detect formalin in food sample in a simple mode and reusable for 4 times application. In addition, the sensor can be regenerated using

Electrochemical engineering approach of high performance solid-state flexible supercapacitor device based on chemically synthesized VS_2 nanoregime structure

Portable and furnished electronics appliances demand power efficient energy storage devices where electrochemical supercapacitors gain much more attention.In this concern,a simple,low-cost and industry scalable successive ionic layer adsorption and reaction(SILAR)approach has been adopted to deposit nanostructured VS_2onto flexible and light-weight stainless steel(SS)substrate towards supercapacitor application.The nanocrystalline nature with hexagonal crystal structure has been confirmed for VS_2through structural analysis.The VS_2electrode exhibits a maximum specific capacitance of 349 F g^(-1)with a super stable behavior in three-electrode liquid-state configuration.Fabricated flexible symmetric solid-state supercapacitor(FSSC)device using gel electrolyte yields specific power of 1.5 k W kg^(-1)(specific energy of 25.9 Wh kg^(-1))with a widen voltage window of 1.6 V.A red LED has been glown for30 s using the system consisted of two devices in series combination.Furthermore,the system glows a combination of 21 red LEDs network with acronym‘VNIT’,demonstrating commercial exposure.The attribution of device demonstration even under mechanical stress holds great promise towards advanced flexible electronics application.

Polyvinyl alcohol–potassium iodide gel probe to monitor the distribution of reactive species generation around atmospheric-pressure plasma jet

This study proposes polyvinyl alcohol–potassium iodide(PVA–KI)as a novel gel chemical probe.The probe uses the reactions among PVA,KI,water,borax,and oxidative species to visualize the distribution of reactive species.This method provides information regarding the distribution of reactive species by coloration on the gel surface.The effects of the surrounding gas phase on the distribution and diffusion of the reactive species are also investigated using the PVA–KI gel probe.Further,the relationship between the irradiation distance and reactive species diffusion is determined on the surface of the PVA–KI probe with and without plastic shielding.Adjusting the irradiation distance appropriately leads to an increase in the modified area as detected by the PVA–KI gel probe analysis.The relative concentration distributions of the reactive species are also obtained from visualized color distributions measured using a colorimeter.Furthermore,reactive species generation by long-scale line plasma is confirmed by the color reaction on the PVA–KI gel surface,with a greater area being covered by an atmospheric-pressure pulsed microwave line plasma source.

软模板法制备聚苯胺干凝胶及在水性防腐涂料中的应用

分别以双十八烷基二甲基氯化铵和双十二烷基二甲基氯化铵为软模板,采用化学氧化法制备聚苯胺干凝胶。通过傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)等对聚苯胺干凝胶进行结构表征;将制备的聚苯胺干凝胶应用于水性防腐涂料中,考察其对水性涂料防腐性能的影响。结果表明,制得的聚苯胺水性防腐涂料具有较好的耐水、耐酸、耐碱、耐中性盐雾性。

Sol-Gel技术与纳米材料的化学剪裁

本文以ＳｉＯ２纳米材料为实例，阐述了ｓｏｌ－ｇｅｌ化学的基本概念，讨论了ＳｉＯ２纳米材料在结构剪裁和性能调控方面的研究进展和前沿问题，并指出ｓｏｌ－ｇｅｌ技术已经成为实现化学剪裁合成纳米材料的主要手段。

Sol-Gel方法制备BST粉体的化学机理和晶化过程研究

以钛酸丁酯、醋酸钡、醋酸锶为原料,乙二醇甲醚为溶剂,采用溶胶凝胶法按Ba∶Sr=0.65∶0.35的组分要求制备了(BaxSr1-x)TiO3粉体.应用FT—IR、X射线、DTA/TGA等分析手段,研究了Sol-Gel方法制备BST粉体过程中的物理化学过程及其晶化行为.实验结果表明:在BST凝胶中,COO—部分进入了凝胶的空间网络结构,起到一种中间连接体的作用;粉体在750℃时,完全晶化.

低渗透裂缝型油田调剖用弱凝胶体系室内评价

通过实验室模拟与现场应用分析,详细考察了弱凝胶体系的性能以及在油田中的实际应用效果。实验结果显示,弱凝胶体系的成胶时间从20℃的115.2 min显著减少至70℃的14.9 min,黏度从1560.5 m Pa·s降至1047.2 m Pa·s,体现了温度提高加速化学交联反应的效果。在老化稳定性实验中,凝胶黏度在室温条件下经过3个月从初始的1200 m Pa·s缓慢降至1149 m Pa·s,而在80℃的高温条件下,从1013 m Pa·s降至970 m Pa·s,表明温度的升高加速了老化过程,但整体上凝胶展示了良好的稳定性。剪切稳定性测试中,凝胶黏度从500 r·min^(-1)的1198 m Pa·s降至5000 r·min^(-1)的987 m Pa·s,显示出良好的剪切稳定性。大洼油田采用弱凝胶调驱技术后,油井的日产油量平均提升了50%,同时减少了水窜现象,优化了油水分层,显著提高了油田的整体采收效率。

化学复合激发对新疆和田地区火山岩的活性影响

针对天然火山岩粉早期活性低的缺点,利用不同化学试剂进行单掺优选、正交复合的试验方案,配合X射线衍射及扫描电子显微镜的微观分析,揭示化学复合激发对火山岩粉胶凝体系活性的影响规律和提升机理.结果表明,化学试剂单掺和复合掺加均能提升火山岩粉胶凝体系的活性,且7 d龄期活性指数表现最佳,试剂单掺最大可提升活性指数至73%,正交试验确定由6%CaO+2%CaCO_(3)+2%CaSO_(4)·2H_(2)O的试剂复合可使7 d龄期活性指数提升至85%,微观水化产物测试发现化学复合激发促使胶凝体系早期Ca(OH)_(2)向高硫型水化硫铝酸钙(AFt)转换的速率加快,使早期胶凝体系内部C-S-H凝胶及AFt晶体生成量增大,水化反应加速,水化产物填充作用明显,提升火山岩粉胶凝体系的早期强度.

CaCl_(2)替代NaCl协同海藻酸钠对虾糜凝胶特性的影响

为减少虾糜中NaCl的添加量,同时提高其凝胶特性,本研究通过测定3D打印效果、凝胶特性、质构特性、流变学性质、蛋白质二级结构和分子化学作用力等指标,在相同离子强度下,探究不同替代量的CaCl_(2)协同海藻酸钠(sodium alginate,SA)对虾糜蛋白结构和凝胶特性的影响。结果表明,在CaCl_(2)-虾糜体系中,随着CaCl_(2)质量分数(0%~0.5%)的增加,虾糜凝胶的硬度、凝胶强度、β-折叠相对含量和氢键含量显著上升(P<0.05),而凝胶持水力呈现逐渐减小的趋势(P<0.05),3D打印支撑性变差。高浓度的CaCl_(2)(质量分数0.5%)会使蛋白出现过度聚集,不利于形成良好的凝胶结构,导致凝胶持水性降低。添加SA提高了虾糜凝胶的持水性。蛋白质二级结构结合化学作用力结果表明,在SA-虾糜体系中,CaCl_(2)的替代对蛋白二级结构无显著影响,但可以提高虾糜凝胶的氢键含量和疏水相互作用,促进凝胶网络形成,改善虾糜凝胶品质。以上结果表明CaCl_(2)替代协同SA能够提高虾糜的凝胶特性与品质,研究结果可为低盐虾糜类产品的研发提供参考。

Sol－gel生长KTa_（1－x）Nb_xO_3电光薄膜的成分和结构

采用ＸＰＳ方法研究了ｓｏｌ－ｇｅｌ工艺制备的ＫＴＮ（ｘ＝０．３５）薄膜的成分和结构．结果表明，除了表面被碳污染外，薄膜中无残余的碳和其他杂质．其成分与原料的化学计量比相近，且沿深度均匀分布．各元素的化学状态证实薄膜系钙钛矿型ＫＴＮ结构．Ａｒ＋溅射后的ＸＰＳ谱反映Ｋ严重偏低，Ｔａ和Ｎｂ的化学状态改变，是Ａｒ＋轰击引起Ｋ择优溅射及化合物分解所致．

云木香二氯甲烷提取物抗肝纤维化活性成分的鉴定

目的 云木香二氯甲烷提取物中抗肝纤维化(HF)活性成分的鉴定。方法 云木香药材的粗粉用95%乙醇回流提取,所得浸膏用水溶解,再用石油醚、二氯甲烷、乙酸乙酯及正丁醇依次萃取得到粗提物;应用硅胶、中压色谱分离凝胶(MCI)、Sephadex LH-20凝胶等柱色谱和制备液相色谱等技术对云木香二氯甲烷萃取部位进行分离纯化,采用核磁共振波谱和质谱进行结构鉴定;采用噻唑蓝(MTT)法测定化合物对人肝星状细胞(HSC)株LX-2的增殖作用影响,评价各化合物的抗HF作用。结果 从云木香二氯甲烷部位中分离到16个化合物,鉴定为木香烯内酯(化合物1)、脱氢木香内酯(化合物2)、β-环木香烯内酯(化合物3)、7α-木香醇(化合物4)、瑞诺木烯内酯(化合物5)、10α-羟基青蒿酸(化合物6)、8α-羟基-11β-11,13-二氢去氢海桑内酯(化合物7)、vlasouliolione B(化合物8)、珊塔玛内酯(化合物9)、草蒿素(化合物10)、4-O-和厚朴酚(化合物11)、2,2-氧双(1,4)-二叔丁基苯(化合物12)、桦木酸(化合物13)、4-羟基-3,5-二甲氧基苯甲醛(化合物14)、5-羟甲基糠醛(化合物15)及茴芹内酯(化合物16);活性测试表明,化合物2、8、9及11可以有效抑制LX-2细胞的增殖,半数抑制浓度(IC50)分别为14.9、51.1、47.2及40.8μmol/L。结论 化合物4、11、12及16为首次从云木香二氯甲烷部位中分离得到,化合物2、8、9及11可能是云木香的主要抗HF活性成分。

溶蚀作用下硅酸三钙水化产物微结构演变机理研究

处于水下区的大坝混凝土由于钙离子溶出易遭受溶蚀破坏,从而造成水泥水化产物脱钙溶解,进而导致大坝混凝土性能劣化失效。为深入揭示大坝混凝土溶蚀劣化机理,有必要厘清溶蚀作用下水泥水化产物形貌与微结构的演变规律。硅酸三钙(C_(3)S)是水泥的主要矿物相,其水化产物特性对水泥及混凝土性能影响显著。为此,本研究制备了高纯度C_(3)S单体,加水水化后浸泡在不同浓度氯化铵溶液中模拟水泥水化产物的加速溶蚀,并结合热重分析、核磁共振、扫描电镜、氮吸附等微观测试方法对其溶蚀前后产物的组成、微纳观结构与形貌进行表征。结果表明硅酸三钙水化产物与氯化铵溶液发生中和反应,溶液的pH值升高;氯化铵浓度越大,反应后溶液的pH值相对越低、水化产物脱钙程度越大,证实了溶蚀程度与环境条件密切相关;溶蚀减少了水化产物中水化硅酸钙凝胶中的化学结合水含量,使硅链结构发生聚合、孔隙结构被粗化并加剧水化硅酸钙凝胶的空心程度,且结构和形貌变化程度随溶蚀程度的增加而增大,从微纳观尺度为揭示混凝土溶蚀机理提供了依据。

化学修饰的溶胶-凝胶(Sol-Gel)法制备YBCO薄膜图形的研究

化学修饰的Sol-Gel法因无需光刻胶、腐蚀液被用于YBCO薄膜图形的制备。以丙烯酸(AA)、苯酰丙酮(BzAcH)作为化学修饰剂制备YBCO薄膜图形,研究了化学修饰剂、光源、前烘温度和时间、溶洗剂对薄膜图形的最小线宽和质量的影响。