bluuebunny/crossref_metadata_2025 huggingface dataset:
BGV theorem, geodesic deviation, and quantum fluctuations
Authors: Kothawala Dawood
Published: December 2020

I point out a simple expression for the ‘Hubble’ parameter

H

, defined by Borde, Guth and Vilenkin in their proof of past incompleteness of inflationary spacetimes. I show that the parameter

H

which an observer O with four-velocity
v
will associate with a congruence
u
is equal to the fractional rate of change of the magnitude ξ of the Jacobi field
ξ
associated with
u
, measured along the points of intersection of O with
u
, with its direction determined by
v
. I then analyse the time dependence of

H

and ξ using the geodesic deviation equation, computing these exactly for some simple spacetimes, and perturbatively for spacetimes close to maximally symmetric ones. The perturbative solutions are used to characterise the rms fluctuations in these quantities arising due to possible fluctuations in the curvature tensor.
Simulation of cell deformation inside a microfluidic channel to identify parameters for mechanical characterization of cells
Authors: Schuster Ralf , Marti Othmar
Published: December 2020

The mechanical characterization of different cell types is important to improve the physiological understanding of cells. Cell types can be differentiated by their elasticity, which is a measure of the amount of deformation under a given stress. Simulations based on the finite element method help us to understand, verify and improve the analysis of deformation-based cell characterization methods such as flow-based cytometry. We achieve efficient computations using a 2D-rotationally symmetric model, based on fluid-structure interaction with a hyper-elastic material. The deformation of a cell along the entirety of a microfluidic channel can be tracked for a variety of elasticities, viscosities, cell sizes, channel geometries and flow rates. The model is even able to simulate soft cells with Young’s modulus of a few hundred pascals in microfluidic channels up to 2 mm in length. Simulations can be carried out in media with constant viscosity as well as in non-Newtonian fluids with shear-dependent viscosity. We have shown that the cell carrier-medium has a strong influence on cell deformation. The position of steady-state deformation dependence on cell properties is investigated. Furthermore, the simulation model can reproduce experimentally observed relaxation of cells, which can then be mapped to actual material parameters to classify and distinguish different cell types.
Roughness evolution in strongly interacting donor:acceptor mixtures of molecular semiconductors. An in situ, real-time growth study using x-ray reflectivity
Authors: Duva G , Pithan L , Gerlach A , Janik A , Hinderhofer A , Schreiber F
Published: December 2020

The evolution of surface roughness in binary mixtures of the two molecular organic semiconductors (OSCs) diindenoperylene (DIP) as electron-donor and 1, 3, 4, 5, 7, 8-hexafluoro-tetracyano naphthoquinodimethane (F6TCNNQ) as electron-acceptor is studied. We co-deposit DIP and F6TCNNQ in vacuum with varying relative molar content while keeping a molar excess of DIP in order to produce phase-heterogeneous mixtures. The excess DIP phase segregates in pristine crystallites, whereas the remaining mixed phase is constituted by DIP:F6TCNNQ co-crystallites. We calculate the surface roughness as function of film thickness by modelling x-ray reflectivity data acquired in situ and in real-time during film growth. To model the experimental data, two distinct approaches, namely the kinematic approximation and the Parratt formalism, are applied. A comparative study of surface roughness evolution as function of DIP:F6TCNNQ mixing ratio is carried out implementing the Trofimov growth model within the kinematic approximation. Depending on the thickness regime, mixing ratio-specific trends are identified and discussed. To explain them, a growth mechanism for binary heterogeneous mixtures of strongly interacting OSCs is proposed.
Facile and scalable fabrication of Ni cantilever nanoprobes using silicon template and micro-electroforming techniques for nano-tip focused electrohydrodynamic jet printing
Authors: Hu Yaming , Su Shijie , Liang Junsheng , Xin Wenwen , Li Xiaojian , Wang Dazhi
Published: December 2020

Electrohydrodynamic jet (E-Jet) printing is a powerful technique for micro/nanostructure fabrication with high resolution and efficiency. However, conventional E-Jet printing are still limited in printing accuracy and ink adaptability due to the nozzle clogging effect. In this paper, we develop a nano-tip focused electrohydrodynamic jet (NFEJ) method to print high-resolution structures. The Ni cantilever nanoprobes with nanoscale radius of curvature (ROC) on their tips were manufactured by a facile and scalable method using silicon template and micro-electroforming technique. Scanning electron microscope was used to analyse the micromorphology of the silicon template with inverted pyramid pits, which was obtained from anisotropic wet etching of silicon. Electroforming mold was obtained by photolithography and plasma etching which divide the top side of Ni film into isolated cantilever pits. Ni cantilever nanoprobes with an average tip ROC of about 48 nm were achieved by the subsequent micro electroforming process. High-resolution droplets array with an average diameter of about 890 ± 93 nm were printed by the NFEJ printing head equipped with these Ni nanoprobes, which verified the practicality of the developed Ni nanoprobes for NFEJ printing.
Preparation of high-quality graphene oxide-carbon quantum dots composites and their application for electrochemical sensing of uric acid and ascorbic acid
Authors: Ding Ling , He Huan , Zhou Jin , Wang Dini , Nian Qiong , Li Shiqian , Qian Shihui , Li Wenbing , Liu Cui , Liang Zhengyong
Published: December 2020

Graphene oxide-quantum dots systems are emerging as a new class of materials that hold promise for biochemical sensing applications. In this paper, the eco-friendly carbon quantum dots (CQDs) are prepared with cheap and recyclable coke powders as carbon source. The graphene oxide-carbon quantum dots (GO-CQDs) composites are synthesized using graphene oxide as the conductive skeleton to load the CQDs by a one-step calcination method. The obtained GO-CQDs composites demonstrate the successful decoration of CQDs on GO nanosheets. The CQDs acting as spacers create gaps between GO sheets, resulting in a high surface area, which electively increases the electrolyte accessibility and electronic transmission. The electrocatalytic activity and reversibility of GO-CQDs composites can be effectively enhanced by tuning the mass ratio of GO to CQDs and the heating process. Furthermore, a highly sensitive and selective electrochemical sensor for determining uric acid (UA) and ascorbic acid (AA) was developed by modifying GO-CQDs composites onto a glassy carbon electrode. The results show that the linear range, minimum detection limit, and sensitivity of the GO-CQDs electrode for UA detection are 1–150 μM, 0.01 μM, and 2319.4 μA mM−1 cm−2, respectively, and those for AA detection are 800–9000 μM, 31.57 μM, and 53.1 μA mM−1 cm−2, respectively. The GO-CQDs are employed as the electrode materials for the serum and urine samples electrochemical sensing, the results indicate that the sensor can be used for the analysis of real biological samples.
Bethe ansatz approach for dissipation: exact solutions of quantum many-body dynamics under loss
Authors: Buča Berislav , Booker Cameron , Medenjak Marko , Jaksch Dieter
Published: December 2020

We develop a Bethe ansatz based approach to study dissipative systems experiencing loss. The method allows us to exactly calculate the spectra of interacting, many-body Liouvillians. We discuss how the dissipative Bethe ansatz opens the possibility of analytically calculating the dynamics of a wide range of experimentally relevant models including cold atoms subjected to one and two body losses, coupled cavity arrays with bosons escaping the cavity, and cavity quantum electrodynamics. As an example of our approach we study the relaxation properties in a boundary driven XXZ spin chain. We exactly calculate the Liouvillian gap and find different relaxation rates with a novel type of dynamical dissipative phase transition. This physically translates into the formation of a stable domain wall in the easy-axis regime despite the presence of loss. Such analytic results have previously been inaccessible for systems of this type.
Finite difference computation of free magneto-convective Powell-Eyring nanofluid flow over a permeable cylinder with variable thermal conductivity
Authors: Kumaran G , Sivaraj R , Prasad V Ramachandra , Beg O Anwar , Sharma Ram Prakash
Published: December 2020

It is essential to account the variability in thermophysical properties such as thermal conductivity to obtain the characteristics of transport properties in industrial thermal systems more accurately. This phenomenon is especially significant in coating protection for rocket chambers, heat exchangers and power generation, wherein cooling techniques are required for sustaining temperature regulation and structural material integrity. At high operating temperatures, the working fluid and hot walls generally emit appreciable radiation. Mathematical models are therefore required which simultaneously analyse all three modes of heat transfer in addition to viscous flow and a variety of other effects including reactions (corrosion, combustion), mass diffusion and rheological behaviour. The modern thrust in nanoscale materials is a major consideration. Motivated by these applications, in this paper, a theoretical examination is implemented to analyse the impact of thermal conductivity variation and thermal radiation on chemically reacting, free convective Powell-Eyring nanofluid flow over a cylinder. The nanoscale effects are accounted by employing the Buongiorno model. The transformed governing equations are numerically solved by using Keller box method under suitable boundary conditions. The comparison results reveal that the obtained results find an excellent match with the results in the literature. The graphs and tables elucidate the impacts of various pertinent parameters on thermo-solutal transport characteristics. It is to be noted that amplifying thermal conductivity variation rises fluid velocity and temperature. Velocity of the fluid decelerates for elevating Darcy number. Magnifying the radiation corresponds to weak radiative flux and stronger thermal conduction which decrease the heat transfer whereas the mass transfer is increased. Furthermore, nanoparticle concentration decreases with greater first-order chemical reaction and Brownian motion parameter values.
Rotating flow of carbon nanotubes subject to prescribed heat flux condition
Authors: Hayat Tasawar , Haider Farwa , Muhammad Taseer , Alsaedi Ahmed
Published: December 2020

This article intends to describe the three-dimensional flow of nanofluid consisting of carbon nanotubes (CNTs) subject to rotating frame. Disturbance in flow is generated by an exponentially stretching sheet. Prescribed heat flux condition is considered. Darcy-Forchheimer relation is employed to characterize the flow in porous space. System of dimensionless equations is obtained by utilizing adequate transformations. Optimal homotopy analysis algorithm is employed for solution development. Physical interpretation of emerging variables on flow fields and physical quantities is discussed. Skin friction coefficient enhances for local porosity parameter, nanoparticle volume fraction and Forchheimer number. Augmentation for heat transfer rate is noticed through solid volume fraction of nanoparticles.
Dissipative Kerr solitons in optical microresonators with Raman effect and third-order dispersion*
Authors: Wu Chaohua , Fang Zhiwei , Fan Jintao , Chen Gang , Cheng Ya
Published: December 2020

Using the mean-field normalized Lugiato–Lefever equation, we theoretically investigate the dynamics of cavity soliton and comb generation in the presence of Raman effect and the third-order dispersion. Both of them can induce the temporal drift and frequency shift. Based on the moment analysis method, we analytically obtain the temporal and frequency shift, and the results agree with the direct numerical simulation. Finally, the compensation and enhancement of the soliton spectral between the Raman-induced self-frequency shift and soliton recoil are predicted. Our results pave the way for further understanding the soliton dynamics and spectral characteristics, and providing an effective route to manipulate frequency comb.
Delta distribution of electronegative plasma predicted by reformed “spring oscillator” dynamic equation with dispersing force
Authors: Zhao Shu-Xia , Li Jing-Ze
Published: December 2020

In our relevant paper [Zhao S X (2021) Chin. Phys. B
30 055201], a delta distribution of negative ions is given by fluid simulation and preliminarily explained by decomposed anions transport equation. In the present work, first, the intrinsic connection between the electropositive plasma transport equation and spring oscillator dynamic equation is established. Inspired by this similarity, reformed “spring oscillator” equation with dispersing instead of restoring force that gives quasi-delta solution is devised according to the math embodied in the anion equation, which is of potential significance to the disciplines of atomic physics and astronomy as well. For solving the “diffusion confusion”, the physics that determines the delta profile within the continuity equation is explored on the basis that recombination loss source term plays the role of drift flux, which is applicable for fluid model of low temperature plasma, but not the ordinary fluid dynamics. Besides, the math and physics revealed in this work predict that the ratio of recombination or attachment (for electrons) frequency versus the species diffusion coefficient is a very important parameter in determining the delta distribution, as it acts as the acceleration of object, according to the reformed oscillator equation. With this theory, the analogous delta profile of electrons density in the famous drift and ambi-polar diffusion heating mechanism of electronegative capacitively coupled plasma is interpreted.
Reconstruction of functional uterine tissues through recellularizing the decellularized rat uterine scaffolds by MSCs in vivo and in vitro
Authors: Li Xia , Wang Yiming , Ma Ruoyu , Liu Xin , Song Biaobiao , Duan Yongchao , Guo Jia , Feng Guihai , Cui Tongtong , Wang Liu , Hao Jie , Wang Hongmei , Gu Qi
Published: December 2020

Infertile people who suffered from loss of uterine structures and/or functions can be treated through gestational surrogacy or uterus transplantation, which remains challenging due to the ethical and social issues, the lack of donor organs as well as technical and safety risks. One promising solution is to regenerate and reconstruct a bioartificial uterus for transplantation through the engineering of uterine architecture and appropriate cellular constituents. Here, we developed a well-defined system to regenerate a functional rat uterine through recellularization of the decellularized uterine matrix (DUM) patches reseeded with human mesenchymal stem cells (hMSCs). Engraftment of the recellularized DUMs on the partially excised uteri yielded a functional rat uterus with a pregnancy rate and number of fetuses per uterine horn comparable to that of the control group with an intact uterus. Particularly, the recellularized DUMs enhanced the regeneration of traumatic uterine in vivo because of MSC regulation. The established system here will shed light on the treatment of uterine infertility with heterogeneous DUMs/cell resources through tissue engineering in the future.
Land-use impacts of Brazilian wind power expansion
Authors: Turkovska Olga , Castro Gabriel , Klingler Michael , Nitsch Felix , Regner Peter , Soterroni Aline Cristina , Schmidt Johannes
Published: December 2020

While wind power is a low-carbon renewable energy technology with relatively little land footprint, the necessary infrastructure expansion still has land-related environmental impacts. Brazil has seen more than a ten-fold increase in wind power capacity in the last decade. However, little is known about these impacts of wind power generation in Brazil compared to other world regions, although Brazilian wind power infrastructure is concentrated in the least protected ecosystems that are prone to degradation, desertification and species extinction. This study focuses on land-use impacts of past wind power generation development in four Brazilian federal states, covering 80% of the country’s installed capacity. We assessed their spatial installation patterns, associated land-use and land cover change in the period before installation until 2018, and potential alternative installation locations, using a detailed wind turbine location database in combination with a high-resolution land-use and land cover map. In contrast to wind parks built in Europe, we found that 62% of the studied wind park area was covered by native vegetation and coastal sands. Overall, 3.2% of the total wind cluster area was converted from native vegetation to anthropogenic use. Wind parks installed mainly on native vegetation, on average, underwent higher land-use change compared to other wind parks. As Brazil intends to more than double its current wind power capacities by 2029, we explored possibilities to reduce environmental risks due to wind power expansion. We showed that this is feasible by integrating wind parks into human-altered areas, as sufficient wind resources there are available.
Renormalizing Yukawa interactions in the standard model with matrices and noncommutative geometry
Authors: Gesteau Elliott
Published: December 2020

We show that gauge-independent terms in the one-loop and multi-loops β-functions of the standard model can be exactly computed from the Wetterich functional renormalization of a matrix model. Our framework is associated to the finite spectral triple underlying the computation of the standard model Lagrangian from the spectral action of noncommutative geometry. This matrix-Yukawa duality for the β-function is a first hint towards understanding the renormalization of the noncommutative standard model conceptually, and provides a novel computational approach for multi-loop β-functions of particle physics models.
Exploration potential of Zhaoxian shale gas of Carboniferous Benxi Formation in Ordos Basin
Authors: Fu Jinhua , Wei Xinshan , Huang Daojun , Zhang Hui , Jia Yani , Liu Yan , Liu Wenxiang
Published: December 2020

In recent years, the domestic study on shale gas has been affected greatly by significant research achievements of overseas marine-facies shale gas exploration and development. In order to study exploration potential of Zhaoxian shale gas of Carboniferous Benxi Formation in Ordos Basin, the petrology, organic geochemistry and gas-bearing capacity of Zhaoxian shale samples from Benxi Formation were investigated. Based on these parameters, the exploration potential of these shales were estimated by applying mathematical statistics and analysing logging response characteristics. Results showed that the Zhaoxian shale was located in the lower part of the Benxi Formation, it was formed in a marine sedimentary environment with a thickness of 15-30m, logging was characterized by higher gamma anomalies and high compensation neutrons. The brittle minerals were mainly quartz, carbonate rock and pyrite, with an average of 36.9%, and a maximum of 50.9%. The total organic carbon (TOC) content was greater than 1% in general and the average value was 2.8%. Organic matter type of the shale samples was mainly type II2 and a few samples were of type II1 organic matter. Vitrinite reflectance values (1.82% on average) showed that shale samples were at mature-high mature stage, which enables good pyrolysis gas generation. The desorbed gas content ranged between 0.34∼2.01 m3/t with an average of 0.99 m3/t. All the evidences indicate that Zhaoxian shale from Carboniferous Benxi formation was of great potential for shale gas exploration.
Coal forming environment and coal accumulation law of Upper Paleozoic in Huanghua Depression
Authors: Li Chuanming , Zhao Changyi , Li Hongjun , Liu Haitao , Zhang Hong , Cui Yu , Yang Runze
Published: December 2020

The characteristics of sequence stratigraphy, geochemistry and coal petrology of Taiyuan and Shanxi formations of Upper Paleozoic in Huanghua depression are systematically analyzed in this paper, It is considered that the thick coal seams in the study area are formed near the transgressive surface, while the coal seams formed at the most flooding surface are not so thick. The thick coal seams are mostly formed in the transgressive system tract, and the coal seams in the highstand system tract are relatively thin, and the coal seams in the lowstand system tract are hardly developed. There are mainly three coal forming models in the study area: ① the land surface coastal coal forming model; ② the abandoned clastic system tract coal forming model; ③ the shallow water delta coal forming model. The main coal forming model is the epicontinental seashore coal forming mode, and the Taiyuan Formation thick coal seam is mainly formed in the epicontinental seashore coal forming mode, and the Shanxi Formation thick coal seam is mainly formed in the waste clastic coal forming mode.
Discussion about the contribution of water to the shale gas reserves within high-over matured shale rocks
Authors: Li S D , Xu J B , Wei Z W , Wang H Z , Deng Q , Cheng B , Liao Z W
Published: December 2020

The shale gas currently exploited in China is mainly featured by high thermal maturity level and the methane concentration is generally more than 95% (v/v). The H/C atomic ratios of residual kerogen gradually decreased with the maturity whereas the source of elemental hydrogen contribution to the shale gas generation within high-over matured shale rocks is still vague. In recent years, some work indicated that the methane generation and its hydrogen isotope characteristics were greatly affected by elemental hydrogen from external water at the over-mature stage in shale rocks. The significance of water should be probed in the processes of geochemical degradation of residual kerogen and hydrocarbon generation in shales. It will be very meaningful to perform the hydrous pyrolysis experiments with heavy water to quantitatively appraise the impact of water on the hydrocarbon generation within shale rocks. A better understanding of the role that water plays on the shale gas generation and enrichment can be hopefully attained.
Modeling hydrocarbon generation of the Wenchang formation in Zhu III Sub-basin, Pearl River Mouth Basin South China by confined pyrolysis
Authors: Li S X , Liu J Z , Li Y C , Li S Q
Published: December 2020

The Zhu III Sub-basin is an important petroliferous basin in the Pearl River Mouth Basin. To obtain the evolution of liquid and gaseous hydrocarbon of the kerogen in the Zhu III Sub-basin, a sample of Wenchang formation in the sub-basin was used in the confined pyrolysis experiments in the present study. The results show that the kerogen has very good hydrocarbon generation potential, with the maximum ΣC1-C5 and ΣC6+ yields of 999.69ml/g·TOC and 808.71mg/g·TOC, respectively, at 600°C. To further study the process of the process of hydrocarbon generation in geological conditions of the sub-basin, the burial, temperature, and thermal history are reconstructed. The kerogen of Wenchang formation started to generate oil and gas at 37Ma and 25Ma, respectively. The transformation ratio value of ΣC6+ reached 100% at 14.45Ma, and that of ΣC1-C5 reached 37%, mainly ΣC2-C5, at present.
Improved TOC prediction method for shale reservoir of Wufeng Formation and the Lower part of Longmaxi Formation in Jiaoshiba Area, Sichuan Basin
Authors: Jia Rong , Xiaorong Luo , Yuping Li , Chao Li , Quanchao Wei , Guangchun Yu
Published: December 2020

The total organic carbon (TOC) content is the core index of shale gas reservoir evaluation. It is of great significance to quickly and accurately obtain a large number of TOC values for shale gas reservoir evaluation and sweet spots identification. The Lower Paleozoic shale gas reservoirs in southern China were once buried to a depth of more than 6000m, and the diagenesis was relatively complete. The application of various TOC estimation methods was not satisfactory so far. This paper takes the shale of Wufeng Formation and the Lower part of Longmaxi Formation in Jiaoshiba area of Sichuan Basin as the key research object. Based on the analysis and summary of well logging results, a method to improve the accuracy of TOC prediction is proposed. The improved ΔLogR technology with the participation of natural gamma-ray and bulk density logs has strong applicability, leading to accurate calculated TOC content, which has important guiding significance for exploration and development.
The role of exogenous oxygen in organic acid generation in deep reservoirs of petroleum-producing basins: Progress and prospects
Authors: Sun Zhenyu , Xu Jie , Chen Jian , Wang Susu , Jia Wanglu , Peng Pingan
Published: December 2020

The source, yield, and distribution of organic acids in oilfield waters in petroleum-producing basins have not been satisfactorily explained by previous studies that have focused on oxygen-containing functional groups in kerogen as the major source of such acids. This study reviews four possible mechanisms by which exogenous oxygen can participate in petroleum or organic acid generation. Biodegradation and mineral oxidation generate organic acids in oilfield waters, leading to an increase in the oxygen content of altered oils, which then have greater potential for producing organic acids. Hydrolytic disproportionation reaction and thermochemical sulfate reduction reactions at high temperatures lead to the in situ generation and accumulation of organic acids in deep reservoirs. The incorporation of exogenous oxygen increases the yield and expands the distribution of organic acids in reservoirs at various depths. The acids derived from exogeneous oxygen play critical roles in the development and preservation of deep reservoirs. Further research is required to determine the volumes and compositions of organic acids produced by these reactions, and to further understand the role of organic acids in the alteration of deep reservoirs under more realistic conditions.
Development characteristics and formation stages of tectonic fractures of Cretaceous Bashijiqike tight sandstone reservoir in Keshen gas field, Tarim Basin, China
Authors: Wang C L , Zhang C Z , Xiao X J , Tang Y L , Yang X J , Li H B , Mo T , Song B H , Fan K Y
Published: December 2020

The Cretaceous Bashijiqike formation in the Kuqa Depression of the Tarim Basin is ultra-low porosity and ultra-low permeability reservoir, where fractures have important influences on single well productivity and natural gas accumulation. According to the core CT scanning, casting thin section, laser copolymerization, imaging logging and other data, the basic development characteristics of fracture in this area are analyzed. Based on the analysis results of the core fracture cutting relationship, the carbon and oxygen isotope of the fractures filling, and the temperature measurement of the inclusions, the main stages of the regional fractures are determined. The results show that the fractures in the study area are mainly high angles, mostly filled with calcite and gypsum, and the fracture width is generally less than 0.2mm. There are three groups of structural fractures, which are EW/NE-SW and NW-SE, with the dominant orientations being NE-SW and NW-SE. The structural fracture were formed in three stages, which were the late Yanshan movement period-early Himalayan tectonic movement, the middle period of Himalayan, and the late period of Himalayan tectonic movement. The tectonic activity of the late Himalayan tectonic movement is the strongest, and the formation of fractures formed in this period were low degree of filling and effective.
Molecular and carbon isotopic characteristics of C6-14 hydrocarbons in the condensates from Kekeya oil field, Southwest Depression of the Tarim Basin, China
Authors: Wang Q , Jia W L , Yu C L , Zou Y R , Peng P A
Published: December 2020

The condensates are important oil resources generally reserved in deep layers and mainly composed of light hydrocarbons. In this study, 10 condensates samples were collected from the Southwest Depression of the Tarim Basin, and treated with the purge-and-trap and headspace single-drop microextraction (HS-SDME) techniques to study the chemical and carbon isotope composition of the C6-14 hydrocarbons. The relative amount of C6-14 hydrocarbons is significantly different between the samples. But there is still a good linear relationship between each two of the C6-9/C10-14, nC6-9/nC10-14 and iC6-9/iC10-14 ratios, indicating that the n-alkanes and isoalkanes (including aromatics) are approximately evaporated with the same ratio. And the relative amount of C6-14
n-alkanes in the samples is deceased as the depth increasing. The δ13C values of the C7-14 n-alkanes are in a range of -30.5‰∼-25‰, and consistent with the δ13C values of C14+
n-alkanes that have been reported earlier. The depth might have an unpredicTable effect on the δ13C value when it is over 6000 m, because the samples with the highest and lowest δ13C values all come from the layers at similar depths. This work might suggest that the purge-and-trap and HS-SDME techniques were practicable and reliable methods to study the light hydrocarbons in condensates, and the results could improve the understanding of the condensates from the study area.
Hydrocarbon resource evaluation of deep Paleogene source rock in Dongying Sag
Authors: Wang X H , Chen T , Niu Z C , Li Z , Hou X B , Zhang S C , Wang R , Zhang J
Published: December 2020

The exploration breakthrough of well Fengshenxie 101 once again shows the great potential of sandy conglomerate in deep northern belt of Dongying sag. Based on the oil source correlation, it is confirmed that the condensate oil in this well mainly sourced from the lower part of Es4. The resource of the source rocks are the key factors affecting the exploration of this hydrocarbon system. Based on restoration of original organic matter abundance, the hydrocarbon resources are calculated using genetic method. The total are 4.67 × 108t, indicating that the deep layers of the Dongying sag still have great exploration potential.
Deep and Ultra-deep oil/gas-source correlation methods: A review
Authors: Wu Yingqin , Wang Zhiyu , Yuan Longmiao
Published: December 2020

With the deepening of oil and gas exploration practice, the increasing degree of oil and gas exploration and the increasing demand for oil and gas, the target of oil and gas exploration is gradually transformed into deep and ultra-deep areas. Meanwhile, the genesis of deep and ultra-deep reservoirs has gradually become the focus of research by domestic and foreign scholars. Oil/gas source correlation is an important means to study the genetic relationship between oil and gas and source rocks. Based on the geological and geochemical data, this paper summarizes and analyzes the advantages and disadvantages of the current methods of deep and ultra-deep oil/gas source correlation, and puts forward the existing problems and future development direction of deep and ultra-deep oil/gas source correlation.
Characterization of the import of Botryococcus to the source rocks of the upper member of the Lower Ganchaigou Formation in the Yingxi area, Qaidam basin, China
Authors: Xu Li , Xing Lantian
Published: December 2020

Substantial quantities of Botryococcus fossils have been detected in the source rocks of the upper member of the Lower Ganchaigou Formation in the Yingxi area, Qaidam basin, China. Dicyclic terpane biomarkers, predominantly drimanes or homodrimanes with the same characteristics, also have been detected in extracts from the source rocks. These salient features confirm that Botryococcus is an important parent material for the high-quality source rocks of the upper member of the Lower Ganchaigou Formation of the western Qaidam basin. Our findings contribute to a better understanding on this source rock series and its mechanisms of hydrocarbon generation.
Organic carbon, bitumen content and maturity of Lower Cambrian source rocks in the northern margin of Tarim Basin
Authors: Yang Haijun , Yu Shuang , Zhang Haizu , Li Tengfei , Zhang Huifang , Chen Chengsheng , Fan Shan , Cheng Bin , Jia Wanglu , Liao Zewen , Tian Hui , Wang Yunpeng
Published: December 2020

The lower Paleozoic area in Tarim Basin is the key field of deep oil and gas exploration, and the lower Cambrian source rock is the focus of current research. However, due to the deep burial depth, there are few samples of Lower Cambrian source rocks revealed by drilling. The lower Cambrian source rocks are widely exposed in the northwest of the basin, which provides a good opportunity for the study of source rocks. In this paper, the organic geochemistry of three sections and a shallow drill sample from Aksu Area in the northwest and Kuruktag area in the northeast of the basin has been systematically analyzed. The total organic carbon (TOC), bitumen content and maturity of source rocks are studied. The organic carbon content of the lower Cambrian source rocks in the Keping area of the northwest basin ranges 1.49%-14.07%, and the content of bitumen ranges 7.73-24.53 mg / g • TOC. However, the organic carbon content of the lower Cambrian outcrop samples in the Sugetebulake section ranges from 0.93% to 7.90%, and the soluble organic matter content ranges from 0.73 to 5.89 mg / g • TOC. The TOC of Lower Cambrian source rocks in Yardang mountain area of northeast basin is low, ranging from 0.75% to 1.42%, and the content of bitumen is between 2.97-3.94 mg / g • TOC. In terms of organic matter abundance, the Cambrian source rocks developed in gentle slope facies are better than those in deep-water shelf facies. The measured reflectance (Ro%) of Shairik shallow drilling samples is between 1.0% - 1.7%, with an average of 1.45%. The Ro% of Sugatebulak samples is between 1.4%-1.75%, with an average of 1.55%, indicating that the overall maturity of the source rocks in the northwest is in the condensate wet gas stage. The measured reflectance of the Cambrian source rocks in the Yardangshan and Kuruktag sections in the northeast of the basin is between 1.5-2.5% RO, with an average of 1.75% ro. The overall maturity of the source rocks in the northeast of the basin is relatively higher, suggesting a wet gas stage.
Study on the characteristics of in-situ gas desorption from the Wufeng - Longmaxi shale in the Sichuan Basin
Authors: Zhenheng Yang , Ming Fan , Baojian Shen , Menhui Qian , Lingjie Yu , Ershe Xu
Published: December 2020

Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation shale in the Sichuan Basin and its periphery is an important horizon for shale gas exploration and development in my country. The rapid on-site desorption instrument independently developed by Sinopec Wuxi Institute of Petroleum Geology was used to test the desorption gas volume, lost gas volume, total gas content, natural gas components of desorbed gas and carbon isotope of methane in typical shale gas wells in this area. Data analysis shows that the carbon isotope value and characteristics of the first sample of methane can predict shale gas enrichment layers, and the total gas content and desorbed natural gas components can identify shale gas sweet spots; shale gas components and carbon isotope values can jointly identify shale gas Genesis type, kerogen carbon isotope characteristics and shale gas carbon isotope characteristics can be used as effective means for gas source comparison; shale gas composition characteristics can distinguish the preservation conditions of the area, which are indicative for the study of the degree of shale gas loss; The combined application of total gas content and initial dissipation index can better identify the sweet spots of shale gas, and avoid single-factor identification of sweet spots; the carbon isotope value of methane shows obvious fractionation effect with desorption time, which can predict shale gas production stage and residual gas content.
Dissolution of arkose under conditions relevant to deep reservoirs: the effect of organic acid on the porosity and pore size distribution of arkose
Authors: Zhang Chen , Li Yuanju , Chen Kefei , Zhou Shixin , Li Jing , Li Pengpeng , Sun Zexiang , Meng Bingkun , Fu Deliang
Published: December 2020

The organic acid is important in forming secondary pores and enhancing total porosity of the clastic rock. But there is little study to investigate the effect of organic acid on the porosity distribution of clastic rock from deep reservoirs. The changes in porosity, permeability, and porosity distribution of the dissolved medium-grained lithic arkose, from Yanchang Formation in Ordos Basin, were examined by nuclear magnetic resonance (NMR). The results show that porosity and permeability of rock increase with the time of exposure of the rock to the organic acid solution and it increases rapidly in the early period, then slightly increases to a saturation level. Besides, organic acid mainly changes the frequency and the shapes of T2 distribution in NMR analysis, and this study suggests that organic acid has more effect on rocks with larger pore throat than those with smaller pore throat.
Study on simulation of reservoir-controlling of fault-unconformity composite transport in Chengbei Fault Zone
Authors: Hong Zhang , Xianzheng Zhao , Jufeng Wang , Haitao Liu , Hongjun Li , Changyi Zhao , Xiaowei Dong , Da Lou
Published: December 2020

Due to the multi-phase tectonic movements in Chengbei Fault Zone, a superimposed pattern of Paleozoic buried hill and Cenozoic fault-step slope was developed on the North China platform. The fault–unconformity composite transport played a vital role in the oil and gas supply for the underlying buried hill and the distal high slope, resulting in the accumulation forming of multi-layer multi-type oil and gas. On the basis of seismic and well logging data, the characteristics of fault–unconformity composite transport in Chenghai buried hill and southern high slope were determined. And the reservoir-controlling mechanisms of fault–unconformity composite transport were revealed through oil and gas filling simulation experiments under different transport conditions. The results showed that the composite transport of fault and unconformity in buried hill zone was beneficial to the forming of large-scale reservoirs, and the dominant thick reservoirs or even negative tectonics under unconformity with abundant oil source were the main hydrocarbon accumulation area. As to the forming of reservoirs in the high slope, the key was the lithology configurations around the unconformity of “upper sand and lower mud” and “upper gravel and lower mudstone”. With the help of fault, the composite transport enables long-distance migration of oil and gas from the northern source rocks in Shahejie Formation, leading to hydrocarbon accumulation above the unconformity of Guantao Formation and even in the structural trough of southern high slope. These results revealed that fault–unconformity composite transport was helpful to hydrocarbon accumulation on a large scale, and even negative tectonics in buried hill below unconformity or structural troughs in high slope above unconformity are potential to form reservoirs. This provides a useful reference for theoretical research on reservoir forming in fault basins and a beneficial guidance for oil exploration in similar areas to a certain extent.
Primary productivity and basin redox conditions within the Mesoproterozoic Hongshuizhuang Formation from Chaoyang area, Liaoxi sag
Authors: Zhang Tao , Sun Shouliang , Li Yongfei , Zong Wenming , Sun Qiushi
Published: December 2020

The Mesoproterozoic Hongshuizhuang Formation in Liaoxi sag, northern China, is an important hydrocarbon source unit having good potentials to generate oil and gas. The total organic carbon (TOC) content ranges from 0.54% to 4.07% in the Chaoyang area. Trace element geochemistry was utilized to study the primary productivity and basin redox conditions during the deposition of Hongshuizhuang Formation black shales. The results suggest that primary productivity during the deposition of the Hongshuizhuang Formation was relatively high. The redox-sensitive elements results indicate that the Hongshuizhuang Formation was deposited under euxinic or anoxic bottom water conditions. The degree of environment restriction, diagenesis, reoxygenation, and the presence of free H2S can make some of the redox-sensitive elements proxies and primary productivity proxies not applicable. The high TOC content of the Hongshuizhuang Formation is contributed by high primary productivity in the surface water combined with euxinic/anoxic in the bottom water.
The role of water during gas generation
Authors: Ni Yunyan , Liao Fengrong , Chen Jianping , Zhang Dijia
Published: December 2020

Resources of coal-derived gas in the deep strata are found abundant in China. Recent advances in petroleum geochemistry suggest water may contribute hydrogen and oxygen to the formation of hydrocarbons and oxygenated alteration production. However, the role of water during gas generation has been in debate due to conflicting research results. In this study, a Jurassic coal sample from the Kuqa depression, Tarim Basin, China was artificially matured by nonhydrous pyrolysis and hydrous pyrolysis at isothermal (330 °C, 350 °C, 370 °C for 72h) and non-isothermal (440 °C, 470 °C and 500 °C at heating rate of 2 °C/h) temperatures. Both isothermal and non-isothermal experiments generated more methane but less C3-5 hydrocarbon gases and CO2 non-hydrocarbon gas in the nonhydrous system relative to hydrous conditions. In the isothermal experiment, the nonhydrous pyrolysis generated at most 24% more methane relative to the hydrous pyrolysis, but the hydrous pyrolysis generated 5%∼87% more C3-5 hydrocarbon gas and at most 28% more CO2 relative to the nonhydrous pyrolysis. In the non-isothermal experiment, the nonhydrous pyrolysis generated 25%∼94% more methane relative to the hydrous pyrolysis, but the hydrous pyrolysis generated at most 2.56 times more C3-5 hydrocarbon gas and 1.04 times more CO2 relative to the nonhydrous pyrolysis. In general, the compositional variation trend of hydrocarbon and non-hydrocarbon gases is similar between the isothermal and non-isothermal experiments. This indicates that contribution from the supercritical water in the non-isothermal pyrolysis is not essential. With the presence of water, the secondary cracking of C3-5 alkanes in the hydrous experiments was significantly suppressed, as shown by the relatively higher yield of C3-5 alkanes in the hydrous systems. The availability of exogenous hydrogen from water in the hydrous pyrolysis inhibits the carbon-carbon bond cross linking, thus the reaction pathway of hydrocarbon generation is dominated by the thermal cracking of carbon-carbon bonds. The significant increase in CO2 in the hydrous pyrolysis indicates water is not only the source for exogenous hydrogen but also the source for the excess oxygen accounted for the formation of CO2. The overall geochemical implication of these experimental results is that it is important to consider the role of water in the hydrocarbon generation, especially in the deep strata where both geological and geochemical conditions are complex.
Bioactive micropatterned platform to engineer myotube-like cells from stem cells
Authors: Tijore Ajay , Lee Bae Hoon , Salila Vijayalal Mohan Hari Krishna , Li King Ho Holden , Tan Lay Poh
Published: December 2020

Skeletal muscle has the capacity to repair and heal itself after injury. However, this self-healing ability is diminished in the event of severe injuries and myopathies. In such conditions, stem cell-based regenerative treatments can play an important part in post-injury restoration. We herein report the development of a bioactive (integrin-β
1 antibody immobilized) gold micropatterned platform to promote human mesenchymal stem cell (hMSC) differentiation into myotube-like cells. hMSCs grown on bioactive micropattern differentiated into myotube-like cells within two weeks. Furthermore, the up-regulation of myogenic markers, multi-nucleated state with continuous actin cytoskeleton and the absence of proliferation marker confirmed the formation of myotube-like cells on bioactive micropattern. The prominent expression of elongated integrin-β
1 (ITG-β
1) focal adhesions and the development of anisotropic stress fibers in those differentiated cells elucidated their importance in stem cell myogenesis. Together, these findings delineate the synergistic role of engineered cell anisotropy and ITG-β
1-mediated signaling in the development of myotube-like cells from hMSCs.
Fabrication of microvascular constructs using high resolution electrohydrodynamic inkjet printing
Authors: Zheng Fei , Derby Brian , Wong Jason
Published: December 2020

Fabrication of the intricate anatomy of vasculature within engineered tissue remains one of the key challenges facing the field of tissue engineering. We report the use of electrohydrodynamic (EHD) inkjet printing to create hydrogel-based microvascular tissues with hierarchical and branching channels, whose minimum feature size of 30 μm approaches the physical scale of native capillary blood vessels. The principle relies on the use of complementary thermoreversible gelling properties of Pluronic F127 (PF-127) and gelatin methacryloyl, which served as sacrificial templates and permanent matrices respectively. Human dermal fibroblasts and human umbilical vein endothelial cells were successfully co-cultured within the engineered microvascular tissue constructs for up to 21 days, and attained high cell viability. Tissue specific morphology was maintained on perfusion. The ability to create cellularised, vascularised proto-tissues with high spatial resolution using EHD inkjet printing, provides a new strategy for developing advanced vascular models with the potential to impact upon an extensive range of biomedical applications.
3D cell-printing of tendon-bone interface using tissue-derived extracellular matrix bioinks for chronic rotator cuff repair
Authors: Chae Suhun , Sun Yucheng , Choi Yeong-Jin , Ha Dong-Heon , Jeon Inho , Cho Dong-Woo
Published: December 2020

The tendon-bone interface (TBI) in rotator cuffs exhibits a structural and compositional gradient integrated through the fibrocartilaginous transition. Owing to restricted healing capacity, functional regeneration of the TBI is considered a great clinical challenge. Here, we establish a novel therapeutic platform based on 3D cell-printing and tissue-specific bioinks to achieve spatially-graded physiology for functional TBI regeneration. The 3D cell-printed TBI patch constructs are created via a spatial arrangement of cell-laden tendon and bone-specific bioinks in a graded manner, approximating a multi-tissue fibrocartilaginous interface. This TBI patch offers a cell favorable microenvironment, including high cell viability, proliferative capacity, and zonal-specific differentiation of encapsulated stem cells for TBI formation in vitro. Furthermore, in vivo application of spatially-graded TBI patches with stem cells demonstrates their regenerative potential, indicating that repair with 3D cell-printed TBI patch significantly accelerates and promotes TBI healing in a rat chronic tear model. Therefore, our findings propose a new therapeutic strategy for functional TBI regeneration using 3D cell-printing and tissue-specific decellularized extracellular matrix bioink-based approach.