查找使用阿拉丁产品的科研文献

Study of Surface Wettability of Mineral Rock Particles by an Improved Washburn Method

Zheng Wang,Yanping Chu,Guozhong Zhao,Zhilin Yin,Tie Kuang,Feng Yan,Lei Zhang,Lu Zhang

The surface wettability of rocks in underground reservoirs affects the distribution of fluids in the reservoir, so the wettability of reservoir minerals is a key factor for crude oil recovery from reservoirs. In this paper, the wettability of quartz sand with different particle sizes in different polar solvents was determined by Washburn’s capillary rise method, and the C·cos θ values were calculated first. Next, the experimentally obtained macroscopic contact angle of water on the quartz surface of 15.0° was substituted into C·cos θ to obtain a linear equation between the particle size of quartz sand and the capillary constant C. The particle sizes of oil sand and mineral powder were then substituted into the equation to obtain their capillary constants C. Then, based on the Owens–Wendt–Rabel–Kaelbe (OWRK) equation and the obtained contact angles of solvent on quartz sand, oil sand, and mineral powder, the surface free energy of quartz sand with different particle sizes is calculated as 76.09, 76.65, and 76.42 mN/m, respectively, which are close to the literature results. In addition, the surface free energy of oil sand with different particle sizes was 23.22, 23.45, and 23.63 mN/m, and the results indicated that the polarity of oil sand was low. Meanwhile, the surface free energies of kaolinite, illite, feldspar, and montmorillonite were 61.59, 32.85, 35.87, and 25.91 mN/m, respectively. By the improved Washburn method in this paper, the wettability of different solvents on the surface of reservoir rocks was investigated, and the surface free energy of specific solid particles was calculated, which is important for studying the extraction of crude oil from subsurface reservoir rocks.

An efficient, scalable approach to hydrolyze flavonoid glucuronides via activation of glycoside bond

Xue-Yang Jiang,Xin-Chen Li,Wen-Yuan Liu,Yun-Hui Xu,Feng Feng,Wei Qu

Hydrolyzing flavonoid glucuronides into corresponding aglycones posed some significant challenges. To improve acid-catalyzed hydrolysis process of flavonoid glucuronide, structures of glucuronide, hydrolysis parameters and post-processing were optimized. The optimized condition was performed by hydrolysis flavonoid glycoside methyl ester in a mixed solvent consisting of 2 mol/L H 2 SO 4 /EtOH/H 2 O (1/8/1, v/v/v) at 95 °C for 7 h and resulted in up to 90% aglycone yields, minimal byproduct formations and milder hydrolysis conditions. Furthermore, the optimized method avoids tedious purification steps and is easily conducted on a relatively large-scale using economical and commercially available reagents.

Interactions between Colloidal Particles in the Presence of an Ultrahighly Charged Amphiphilic Polyelectrolyte

Danfeng Yu,Hui Yang,Hui Wang,Yingxian Cui,Guang Yang,Jian Zhang,Jinben Wang

A novel amphiphilic polyelectrolyte denoted as PAGC8 and a traditional amphiphilic polyelectrolyte denoted as PASC8 were prepared. PAGC8 consisted of gemini-type surfactant segment based on 1,3-bis (N,N-dimethyl-N-octylammonium)-2-propyl acrylate dibromide, while PASC8 incorporated acryloyloxyethyl-N,N-dimethyl-N-dodecylammonium bromide as single chain surfactant units within its repeat unit structure. Turbidity, stability, and zeta potential measurements were performed in the presence of PAGC8 and PASC8, respectively, to evaluate their effectiveness in inducing solid/liquid separations. It was found that the maximum transmittance was observed before the zeta potential values reached the isoelectric point, implying that not only charge neutralization but also charge-patch mechanism contributed to the separation process. Colloid probe atomic force microscopy technique was introduced to directly determine the interactions between surfaces in the presence of ultrahighly charged amphiphilic polyelectrolyte. On the basis of the AFM results, we have successfully interpreted the influence of the charge density of the polyelectrolytes on the phase stability. Electrostatic interaction played the dominant role in the flocculation processes, although both electrostatic interaction and hydrophobic effect provided contributions to the colloidal dispersions. The attractions upon surfaces approach in the case of PAGC8 were significantly larger than that of PASC8 due to the higher charge density. The strong peeling events upon retraction in the presence of PAGC8 implied that the hydrophobic effect was stronger than that of PASC8, which displayed the loose pulling events. A strong attraction was identified at shorter separation distances for both systems. However, these interactions cannot be successfully described by the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory of colloid stability due to the participation of charge-patch and strong hydrophobic effect. To account for the additional interactions, we proposed an extended DLVO empirical model to explain the non-DLVO forces in the systems. A reasonable physical model was also proposed to further describe the interactions between surfaces in the two amphiphilic polyelectrolyte systems.

Gaseous ferrocene as an efficient catalyst for in-situ pyrolysis of oil shale

Lianhua Hou,Bo Sun,Chen Wang,Jing Chen,Baojian Shen,Chunming Xu,Xiaochun Zhu

The cost-efficient exploitation of low- to moderate maturity (LMM) shale is of great significance in ensuring energy security, yet the existing technologies suffer from low pyrolysis efficiency, high energy consumption, and poor quality of product oil and gas. For the first time, this study proposes a novel strategy using gaseous ferrocene as an efficient catalyst for the in-situ catalytic pyrolysis of such shale, leveraging its unique low-temperature sublimation property for uniform dispersion in shale microfractures. Systematic pyrolysis experiments demonstrated that the addition of ferrocene effectively enhanced both the yield and quality of product oil and gas. Under conditions of 0.5 % ferrocene addition and an initial reaction pressure of 2 and 0.5 MPa, the product oil recovery rate increased by 31.67 % and 106.16 %, respectively, as compared with the non-catalytic pyrolysis. The yield of H 2 and light hydrocarbons (CH 4 , C 2 -C 4 ) in the gas products increased significantly, while the proportion of gasoline fraction in product oil rose markedly, with a substantial reduction in heavy oil components. Density functional theory (DFT) calculations demonstrated that ferrocene reduces the energy barrier of C–C bonds and C–O bonds cleavage, supporting the experimental results of enhanced pyrolysis of kerogen.

An ultra-low-consumption dilution strategy for high-performance inverted perovskite solar cells

Yucong Zhou,Jiaqi Pang,Bohao Zhang,Yingying Li,Yan Feng,Bin Zhang,Qing Wang,Rong Liu,Zhitao Shen,Fumin Li

Despite significant breakthroughs in power conversion efficiency (PCE) and operational stability of perovskite solar cells (PSCs), their development remains challenged by lead toxicity risk and high production costs. This study introduces a process-efficient dilution strategy using acetonitrile for the perovskite precursor solution, which reduces the precursor concentration from the conventional 1.4 M to an ultra-low 0.28 M. This approach establishes an eco-friendly and cost-effective processing method, substantially mitigating the risk of lead while lowering raw material consumption. Crucially, acetonitrile regulates nucleation kinetics to enable dense, high-quality perovskite films, yielding champion devices with a PCE of 25.40%. Stability assessments demonstrate exceptional robustness that unencapsulated devices retain 80% of initial PCE after 1224 h of storage in N 2 atmosphere and 82% after 800 h of continuous operation at 30 ± 10% relative humidity. By concurrently resolving toxicity, cost, and performance optimization challenges through solvent engineering, this work provides a fundamental advance for sustainable development of perovskite photovoltaics.

An evaluation of the adsorption dynamics of phosphate ions onto Fe(II)-montmorillonites

QIN DAWEI,CHANG SHUHUA,QIAO MIN,YUAN XIAOTONG,LIU WEI,LIU GANG

Fe(II)-montmorillonites (Fe(II)-MMTs) were prepared by mixing solutions of Fe(II) and montmorillonite at pH 3.5. Two different Fe(II)-MMTs were prepared and the ferrous iron contents were 40 mg/L and 80 mg/L. All samples were characterized by XRD, FT-IR, TGA, DSC, and nitrogen adsorption. By nitrogen adsorption, the pore size can be obtained in the pore diameter curve with average pore widths of 6.67 nm, 9.96 nm, and 17.07 nm, respectively. The removal rate of phosphate increased rapidly during the first 40 min, in which Fe(II)-MMT (1) and Fe(II)-MMT (2) were stronger adsorption systems than MMT. The maximum adsorption was 48.38 mg/g at pH 2.0. The kinetics of phosphate adsorption were better described using pseudo-second-order models (R$^{2}$: 0.997, 0.999, 1.000) than pseudo-first-order (R$^{2}$: 0.933, 0.900, 0.760). R$^{2}$ is the determinable statistic coefficient that measures the goodness of fit. If the R$^{2}$ value is closer to one, the fitting degree of the regression line is better. By the thermodynamic analyses, we obtained the $\Delta $G$^{\circ}$ and $\Delta $H$^{\circ}$ of samples at 298 $^{\circ}$C, 303 $^{\circ}$C, and 310 $^{\circ}$C. The adsorption isotherms also better fitted a Langmuir model in which the process was nonspontaneous and exothermic.

EAP-Swift: An Efficient Authentication and Key Generation Mechanism for Resource Constrained WSNs

Daniel Granlund,Christer Åhlund,Patrik Holmlund

Technological advances within the area of wireless sensor technology allow WSNs to be used in a increasing number of measurement scenarios. As new application areas are emerging, such as infrastructure monitoring and smart cities, the need for sensor mobility handling requires efficient and secure authentication protocols. This paper presents EAP-Swift, a novel EAP based authentication protocol with a focus on lightweight processing and faster response. It supports end-to-end session encryption key generation and mutual authentication. By utilizing lightweight hashing algorithms, the challenge-response authentication mechanism uses only two round trips to the AAA server for the complete authentication procedure leading to the reduction of latency by 33% compared to the baseline protocols. Further, using extensive experimentation, we validate that the authentication time can be kept below 250 ms and the power consumption can be kept below 15 mJ. Furthermore, we show that a battery lifetime of more than four years can be achieved when running the system on a regular button cell battery. Finally, the protocol was verified in terms of security using the AVISPA tool.

Weaving Language and Culture: Latina Adolescent Writers in an After-School Writing Project

Andrea García,Amy Gaddes

A decade ago, the subtractive schooling of many Latino youth in the United States resulted in a devaluing of cultural identity and heritage as resources to support learning. Today, educators are urged to revalue cultural resources toward literacy development. This study explores the experiences of Latina adolescent students as writers during an after-school writing project based in a culturally and linguistically responsive literacy instruction model. We report on the writing experiences of young women from diverse backgrounds as they examined issues of race, power, voice, and linguistic identity through the use of culturally authentic literature. Qualitative analyses of data from writing samples reveal (a) the process of Latina youth “authoring” themselves through writing and (b) the composing of meaning from a “transnational” perspective. We address implications for the education of minority youth.

Determining Content Power Users in a Blog Network: An Approach and Its Applications

Seung-Hwan Lim,Sang-Wook Kim,Sunju Park,Joon Ho Lee

Development of an Electrochemiluminescence Immunoassay for Quantitative Determination of Semaglutide in Human Serum

Yifan Luo,Junyan Zhang,Wenlong Chen,Hefeng Zhang,Linglong Zou

Semaglutide, a long-acting glucagon-like peptide-1 receptor agonist (GLP-1RA), is widely used in the treatment of patients with type 2 diabetes mellitus and obesity. A sensitive and reliable quantification method is essential for bioanalysis of semaglutide in clinical studies. To develop a sensitive and specific immunoassay, we have prepared a pair of highly specific anti-semaglutide monoclonal antibodies and subsequently employed them as critical reagents in the development of an electrochemiluminescence immunoassay (ECLIA) for the quantification of semaglutide levels in human serum. The assay validation data presented here demonstrate that the performance of the ECLIA method meets prespecified criteria for all validation parameters within the quantitative range of 0.5 ng/mL to 200.0 ng/mL. The intra- and inter-assay precision (%CV) are both ≤14.4%, and accuracy (%RE) ranges from −12.5% to 15.3%. No interference is found with recombinant human GLP-1 as the endogenous counterpart, confirming the assay specificity. Additional assay performance parameters, including selectivity, dilutional linearity, hook effect, and sample stability, all meet the acceptance criteria preset in accordance with international guidelines for bioanalytical method validation. The method is suitable for bioanalysis of semaglutide in human serum.

Rapid lectin detection via nanoconfined polysaccharide-protein agglutination in an iontronic nanopore sensor

Yuan Xu,Songbai Cao,Yuheng Liu,Jun Peng,Mingyi Yu,Youjian Liu,Yuhua Cai,Sebastien Balme,Tianji Ma,Zhong Cao

Concanavalin A (Con A) is a glycoprotein binding lectin which involves cytotoxicity, cell death and cancer diagnosis. An iontronic sensor was designed using nano-confined polysaccharide-protein complexation. Dextran was functionalized onto conical track-etched nanopore surface as a lectin probe. When tetramer Con A agglutinate with dextran inside the conical nanopores, the nanopore is effectively blocked by steric hindrance, enabling a molecularly gated response that results in an amplified decrease of ionic conductance. Subsequent elution removes Con A and reopens the channel, allowing the sensor to be regenerated and reused. In 1 mol/L KCl PBS buffer (pH 7.4), the sensor achieved an ultra-low detection limit of 0.19 ng/mL and exhibited a broad linear range from 10 ng/mL to 100 mg/mL, with channel conductivity showing clear logarithmic dependence on Con A concentration. The sensor exhibits excellent selectivity toward Con A and maintains stable performance for 20 days. With its label-free design, simple structure, reusability and successful application in real samples, this iontronic nanopore sensing platform offers a highly promising tool for lectin monitoring and related bioanalytical applications.

Real-time nanomolar vitamin monitoring in sweat using an electrochemical skin-attached device

Xue Wang,Yuzhuo Wang,Yuxin Li,Yujiao Sun,Peiyuan Mao,Simiao Liu,Jieying Ou,Xuemei Wang,Fazheng Ren,Hao Zhang

Invasive and inconvenient blood tests hinder the diagnosis and treatment of micronutrient deficiencies, which affect billions worldwide. Wearable sweat sensors offer a noninvasive and real-time alternative. However, on-body monitoring of multiple low-abundance vitamins in sweat remains challenging. Here, we show a wearable electrochemical platform that utilizes bioreceptor-functionalized gold nanoflower/sulfur and nitrogen codoped carbon to detect six low-concentration vitamins in sweat (vitamins B 1 , B 2 , B 7 , B 9 , B 12 , and D) with nanomolar-level sensitivity. Integrated system incorporates iontophoretic sweat induction, microfluidic sampling and real-time vitamin detection with calibration. Human studies revealed temporal profiles of VB 9 levels in sweat in response to oral VB 9 supplementation and VB 9 -rich diets, and a strong sweat-serum correlation ( r  =  0.849) has been found. The significant differences in VB 9 levels observed between smokers and nonsmokers demonstrated the potential of this technology for vitamin monitoring in diverse populations. Our platform facilitates early detection of nutritional imbalances and advances personalized nutrition. Nutrient deficiencies are widespread, but blood tests are often inconvenient. Here, the authors develop a wearable electrochemical platform for noninvasive, real-time detection of multiple low-concentration vitamins in sweat and validate its performance in human studies.