Preparation of CIP@TiO_(2) composite with broadband electromagnetic wave absorption properties

Scholars aim for the improved impedance matching (Z) of materials while maintaining their excellent wave absorption properties. Based on the hydrolysis characteristics of isopropyl titanate, a simple preparation process for the coating of carbonyl iron powder(CIP) with TiO_(2) was designed. Given the TiO2coating, the Z of the CIP@TiO_(2) composite was adjusted well by decreasing the dielectric constant. Moreover, the interfacial polarization of CIP@TiO_(2) was enhanced. Ultimately, the electromagnetic-wave (EMW) absorption property of the CIP@TiO_(2)composite was improved substantially, the minimum reflection loss reached-46.07 dB, and the effective absorption bandwidth can reach 8 GHz at the composite thickness of 1.5 mm. Moreover, compared with CIP, the oxidation resistance of CIP@TiO_(2)showed remarkable improvement. The results revealed that the oxidation starting temperature of CIP@TiO_(2) as about 400℃,whereas the uncoated CIP had an oxidation starting temperature of approximately 250℃. Moreover, the largest oxidation rate temperature of CIP@TiO_(2) increased to around 550℃. This work opens up a novel strategy for the production of high-performance EMW absorbers via structural design.

Detection of Environmental Toxins in Mixed Matrices of Tap Water, Soil, Food Waste, Serum and Milk Using Hememics Biosensor

Exposure to toxins can lead to a wide range of adverse health effects, including respiratory problems, neurological disorders, cancer, and reproductive issues. Toxins can come from various sources, such as industrial waste, agricultural runoff, and household chemicals. Therefore, detecting and monitoring toxins in the environment is crucial for protecting human health and the environment. This study aimed to evaluate the performance of Hememics biosensor system in detecting environmental toxins such as Ricin and Staphylococcal enterotoxin B (SEB) in mixed matrixes. When Ricin and SEB are spiked into soil, chopped lettuce, tap water, milk and serum, the biosensor was able to detect these toxins, without sample processing, at a level of detection comparable to lab testing with high sensitivity and specificity. Furthermore, Hememics biosensor system is designed to be network-enabled, which means that results can be transmitted to relevant agencies for quick decisions. This feature is crucial in cases where quick action is needed to prevent further contamination or exposure to harmful toxins.

Synergically enhanced piezocatalysis performance of eco-friendly(K_(0.52)Na_(0.48))NbO_(3) through ferroelectric polarization and defects

Piezocatalysis has attracted unprecedented research interest as a newly emerging catalysis technology.However,the inherent insulating property of ferroelectric materials ultimately leads to the poor vibration-electricity conversion ability.Herein,this work reports the(K_(0.52)Na_(0.48))NbO_(3) ferroelectric ceramics(KNNFCx),for which the FeCo modification strategy is proposed.The substitution of the moderate amount of FeCo(x=0.015)at Nb site not only optimizes ferroelectricity but also produces beneficial defects,notably increasing Rhodamine B water purification efficiency to 95%.The pinning effect of monovalent oxygen vacancies on ferroelectric domains is responsible for the excellent ferroelectric polarization of KNNFC0.015 through the generation of an internal field to promote charge carriers separation and reduce nonradiative recombination.Importantly,the accompanying electron carriers can easily move to the material surface and participate in redox reactions because they have low activation energy.Therefore,ferroelectric polarization and defects play synergetic roles in enhancing piezocatalytic performance.

锂金属负极人造保护膜的研究进展

金属锂因其具有极高的理论容量(3860 mAh·g^(−1))、最低的电极电位(−3.04 V vs.标准氢电极)和低的密度(0.534 g·cm^(−3)),被认为是最具潜力的负极材料。但循环过程中不可控的枝晶生长及不稳定的固体电解质相界面膜所引起的安全隐患和电池库伦效率低等问题严重阻碍了锂金属负极的发展。通过在电极表面构建人造保护膜可以有效调控锂离子沉积行为,因此人造保护膜的构建是一种简单高效抑制锂枝晶生长的策略。本综述将从聚合物保护膜、无机保护膜、有机-无机复合保护膜和合金保护膜总结了人造保护膜的构建方法、抑制锂枝晶生长机理,为促进高比能锂金属电池的商业化应用提供借鉴参考作用。

Impact of residual zircon on Nd-Hf isotope decoupling during sediment recycling in subduction zone

The subduction factories in convergent plate margins exert crucial control on recycling terrestrial components and returning to the overlying crust. The Nd and Hf isotopic systems provide potential tracers to evaluate these processes. Here we present a case where these isotopic systems are decoupled in a suite of granites from the Chinese Altai, showing a wide range of εHf(t) values(from -4.7 to +10.8) in contrast to a limited range of εNd(t) values(from -5.8 to -1.9). The zircon xenocrysts occurring frequently in these rocks show markedly negative εHf(t) values(from -34.3 to -6.5) and positive d7 Li values(from +12.5 to +18.2). We propose a model to explain the observed relationship between residual zircon and Nde Hf isotope decoupling. We suggest that the Altai granites originated from partial melting of subducted slab components under relatively low temperature conditions which aided the residual zircon from oceanic sediments to inherit and retain a significant amount of177 Hf in the source, thereby elevating the^(176) Hf/^(177) Hf ratio of the melt, and decoupling from the^(143) Nd/^(144) Nd ratio during the subsequent magmatic processes. Our study illustrates a case where sediment recycling in subduction zone contributes to decoupling of Nd and Hf isotopic systems, with former providing a more reliable estimate of the source characteristics of granitic magmas.

Literature review and economic evaluation of oral and intramuscular ziprasidone treatment among patients with schizophrenia in China

Background Over 10 million Chinese are affected by schizophrenia. The annual cost of schizophrenia in China was estimated at US$2586 per patient.Aims The study has two aims:(1) to conduct a targeted literature review of the economic literature on oral ziprasidone in China, and(2) to develop an inpatient economic model that compared the cost of intramuscular ziprasidone with other regimens including electroconvulsive therapy(ECT) for the management of acute agitation in patients with schizophrenia from a hospital's perspective in China.Methods A targeted literature review was conducted using PubMed and the Chinese literature databases for studies published between January 2007 and December2017. Studies that assessed costs associated with oral ziprasidone treatment for schizophrenia in China were summarised. In the inpatient economic model,cost measures included hospital room and board,antipsychotics,ECT and medications for the management of extrapyramidal symptoms(EPS). Input for standard antipsychotic regimens and unit cost were obtained from the literature. Hospital length of stay(LOS), utilisation of ECT and incidence of EPS were derived from the literature and supplemented/validated with a survey of psychiatrists in China. Cost was presented in 2017 Chinese yuan.Results The average estimated LOS was 29 days with ziprasidone, 33 days with risperidone+benzodiazepine,32 days with olanzapine, 35 days with haloperidol and 29 days with ECT. The cost of antipsychotics was $1260 with ziprasidone, $137 with risperidone+benzodiazepine, $913 with olanzapine and $210 with haloperidol; ECT treatment costs $785. The base-case analysis suggested that higher antipsychotic cost with ziprasidone was offset by savings with shorter LOS. Using intramuscular ziprasidone for acute management was associated with a total cost of $11157, the lowest among all antipsychotic regimens($11 424 with risperidone+benzodiazepine, $11 711 with olanzapine and $11 912 with haloperidol) and slightly higher than ECT($10 606). The cost of antipsychotics and ECT accounted for 1 %-11 % of the total cost. Varying LOS between the lower and upper bounds of the 95% CI, the total cost was comparable between these regimens.Conclusions Overall, the cost for the management of acute agitation was similar between intramuscular ziprasidone and other antipsychotics. Compared with other antipsychotics, the higher medication cost of intramuscular ziprasidone can be offset by savings with shorter hospital stay. The results from this economic analysis were complementary to the findings in the published literature assessing the economic outcomes of oral ziprasidone.

The formation of neutron star systems through accretion-induced collapse in white-dwarf binaries

The accretion-induced collapse(AIC)scenario was proposed 40 years ago as an evolutionary end state of oxygen-neon white dwarfs(ONe WDs),linking them to the formation of neutron star(NS)systems.However,there has been no direct detection of any AIC event so far,even though there exists a lot of indirect observational evidence.Meanwhile,the evolutionary pathways resulting in NS formation through AIC are still not thoroughly investigated.In this article,we review recent studies on the two classic progenitor models of AIC events,i.e.,the single-degenerate model(including the ONe WD+MS/RG/He star channels and the CO WD+He star channel)and the double-degenerate model(including the double CO WD channel,the double ONe WD channel and the ONe WD+CO WD channel).Recent progress on these progenitor models is reviewed,including the evolutionary scenarios leading to AIC events,the initial parameter space for producing AIC events and the related objects(e.g.,the pre-AIC systems and the post-AIC systems).For the single-degenerate model,the pre-AIC systems(i.e.,the progenitor systems of AIC events)could potentially be identified as supersoft X-ray sources,symbiotics and cataclysmic variables(such as classical novae,recurrent novae,Ne novae and He novae)in the observations,whereas the post-AIC systems(i.e.,NS systems)could potentially be identified as low-/intermediate-mass X-ray binaries,and the resulting low-/intermediate-mass binary pulsars,most notably millisecond pulsars.For the double-degenerate model,the pre-AIC systems are close double WDs with short orbital periods,whereas the post-AIC systems are single isolated NSs that may correspond to a specific kind of NS with peculiar properties.We also review the predicted rates of AIC events,the mass distribution of NSs produced via AIC and the gravitational wave(GW)signals from double WDs that are potential GW sources in the Galaxy in the context of future spacebased GW detectors,such as LISA,TianQin,Taiji,etc.Recent theoretical and observational constraints on the detection of AIC events are summarized.In order to confirm the existence of the AIC process,and resolve this long-term issue presented by current stellar evolution theories,more numerical simulations and observational identifications are required.

Carrier and magnetism engineering for monolayer SnS_(2) by high throughput first-principles calculations

Two-dimensional(2D)semiconducting tin disulfide(SnS_(2))has been widely used for optoelectronic applications.To functionalize SnS_(2) for extending its application,we investigate the stability,electronic and magnetic properties of substitutional doping by high throughput first-principles calculations.There are a lot of elements that can be doped in monolayer SnS_(2).Nonmetal in group A can introduce p-type and n-type carriers,while most metals in group A can only lead to p-type doping.Not only 3d,but also 4d and 5d transition metals in groups VB to VⅢB9 can introduce magnetism in SnS_(2),which is potentially applicable for spintronics.This study provides a comprehensive view of functionalization of SnS_(2) by substitutional doping,which will guide further experimental realization.

He-shell flashes on the surface of oxygen-neon white dwarfs

Accretion induced collapse(AIC)may be responsible for the formation of some interesting neutron star binaries(e.g.,millisecond pulsars,intermediate-mass binary pulsars,etc).It has been suggested that oxygen-neon white dwarfs(ONe WDs)can increase their mass to the Chandrasekhar limit by multiple He-shell flashes,leading to AIC events.However,the properties of He-shell flashes on the surface of ONe WDs are still not well understood.In this article,we aim to study He-shell flashes on the surface of ONe WDs in a systematic approach.We investigated the long-term evolution of ONe WDs accreting He-rich material with various constant mass-accretion rates by time-dependent calculations with the stellar evolution code Modules for Experiments in Stellar Astrophysics(MESA),in which the initial ONe WD masses range from 1.1 to 1.35 M_(⊙).We found that the mass-retention efficiency increases with the ONe WD mass and the mass-accretion rate,whereas both the nova cycle duration and the ignition mass decrease with the ONe WD mass and the mass-accretion rate.We also present the nuclear products in different accretion scenarios.The results presented in this article can be used in the future binary population synthesis studies of AIC events.

CVRgram for Demodulation Band Determination in Bearing Fault Diagnosis under Strong Gear Interference

Fault-related resonance frequency band extraction-based demodulation methods are widely used for bearing diagnostics.However,due to the high peaks of strong gear meshing interference,the classical band selection methods have poor performance and cannot work well for bearing fault type detection.As such,the CVRgram-based bearing fault diagnosis method is proposed in this paper.In the proposed method,inspired by the conditional variance(CV)index and root mean square(RMS),a novel index,named the CV/root mean square(CVR),is first proposed.The CVR index has high robustness for the interference of non-Gaussian or Gaussian noise and has the ability to determine the center frequency of the weak bearing fault-related resonance frequency band under strong interference.Secondly,motived by the Kurtogram,the CVRgram algorithm is developed for adaptively determining the optimal filtering parameters.Finally,the CVRgram-based bearing fault diagnosis method under strong gear meshing interference is proposed.The performance of the CVRgram-based method is verified by both the simulation signal and the experiment signal.The comparison analysis with the Kurtogram,Protrugram,and CVgram-based method shows that the proposed technique has a much better ability for bearing fault detection under strong noise interference.

Facile fabrication of graphene/g-C_(3)N_(4) for electromagnetic wave absorption

With the development of the miniaturization of electronic equipment and lightweight weapon equipment,there are new requirements for electromagnetic wave absorption material(EMWAM).EMWAM has outstanding electromagnetic wave absorption properties and lightweight characteristics become an important direction of research.In this study,graphene/g-C_(3)N_(4)(GGCN)EMWAM was first synthesized in situ by simple heat treatment,in which the g-C_(3)N_(4) had a porous structure and dispersed on the surface of graphene.The impedance matching of the GGCN was well adjusted by decreasing the dielectric constant and attenuation constant due to the g-C_(3)N_(4) semiconductor property and the graphite-like structure.The EMW loss mechanism of GGCN was also analyzed by simulating GGCN’s electric field mode distribution and resistance loss power density.The analysis result shows that the distribution of g-C_(3)N_(4) among GGCN sheets can produce more polarization effects and relaxation effects by increasing the lamellar spacing.Furthermore,the polarization loss of GGCN could be increased successfully by porous g-C_(3)N_(4).Ultimately,the EMW absorption property of GGCN is optimized significantly,and GGCN exhibits excellent EMW absorption performance.When the thickness is 2 mm,the effective absorption bandwidth(EAB)can reach 4.6 GHz,and when the thickness is 4.5 mm,the minimum reflection loss(RLmin)at 4.56 GHz can reach-34.69 dB.Moreover,the practical application of EMWAM was studied by radar cross-section(RCS)simulation,showing that GGCN has a good application prospect.

Cobalt phosphide-based composites as anodes for lithium-ion batteries:From mechanism,preparation to performance

With the further requirements of electronic products and powered vehicles,the development of a new generation with low-voltage and high-capacity anode materials is crucial for lithium-ion batteries(LIBs).Transition metal phosphides,especially cobalt phosphide(CoP)composites,have become a research hotspot for LIBs anode materials in recent years due to their high theoretical specific capacity,low polarization,and suitable voltage plateau.This review first systematically discusses the lithium storage mechanism and preparation methods of CoP in current research.Subsequently,the applications of CoP anode materials in LIBs are categorically reviewed,including the composites of CoP with various types of carbon materials and heterostructures.Finally,the challenges and future development directions of CoP anode materials are summarized to provide guidance for further improving the lithium storage performance of CoP and its practical applications.

Flow characteristics of radial inflow in impeller rear cavity with baffle plate

The research purpose of this paper is to explore the influence of the baffle plate on the airflow in the rear cavity of the centrifugal impeller and optimize the performance of the secondary air system’s air bleed section.In this paper,a comprehensive experimental study was carried out on the flow characteristics in the impeller rear cavity with baffle plate.The windage torque,flow structure and pressure drop between inlet and outlet were measured respectively.The experiment was carried out with the condition that the range of rotational Reynolds number was from 8.33×10^(5)to 22.2×10^(5)and the range of mass flow rate coefficient was from 0.92×10^(4)to 2.92×10^(4).The results show that the static cavity and the narrow stator-rotor cavity formed by the baffle plate effectively suppress the overall swirl coefficient in the cavity.Thus,the static pressure and total pressure drop in the rotor-stator cavity were reduced.The influence of the baffle plate on the windage torque of the rotary disk is related to the turbulence parameters.Under large turbulence parameters,the windage torque would be reduced with baffle plate,while under small turbulence parameters,the baffle plate would increase with baffle plate.In general,the baffle plate can improve the flow capacity and optimize the bleed air performance with proper structure and operation conditions.

电针“内关”预处理对心肌缺血再灌注损伤大鼠心肌Akt/mTOR通路的影响

目的观察电针预处理对心肌缺血再灌注损伤(MIRI)模型大鼠心肌组织自噬相关通路Akt/mTOR的影响,探讨电针“内关”对心肌损伤的作用机制。方法将48只SD大鼠按随机数字表法分为空白组、假手术组、模型组和内关组,每组12只。内关组电针刺激大鼠“内关”,每次30 min,1次/d,连续干预7 d。干预结束后,除空白组外,其余各组大鼠采用冠状动脉左前降支结扎法建立MIRI模型。采用HE染色法观察大鼠心肌组织病理形态学改变;Western blot法检测心肌组织Akt、磷酸化Akt(p-Akt)、mTOR、磷酸化mTOR(p-mTOR)蛋白表达,计算p-Akt/Akt、p-mTOR/mTOR比值。结果空白组心肌纤维排列规则整齐,心肌间质未见炎性细胞浸润、出血;假手术组心肌纤维排列稍不规则,未见断裂,可见少量心肌纤维间隙稍扩大;模型组心肌纤维分布紊乱,肥大心肌细胞增多,部分线粒体红肿或外膜破裂,间质可见炎性浸润、出血;内关组心肌组织病变程度较模型组减轻,少量间质出血及炎性细胞浸润。各组大鼠心肌组织Akt、mTOR蛋白表达比较差异无统计学意义(P>0.05);与假手术组比较,模型组p-Akt、p-mTOR表达及p-Akt/Akt、p-mTOR/mTOR降低(P<0.01);与模型组比较,内关组p-Akt、p-mTOR表达及p-Akt/Akt、p-mTOR/mTOR升高(P<0.01)。结论电针“内关”预处理可能通过激活MIRI大鼠心肌细胞Akt/mTOR通路抑制过度自噬,从而减轻MIRI,起到保护心肌的作用。

多囊卵巢综合征患者肠道菌群和生化免疫分子特征

【目的】比较多囊卵巢综合征(polycysticovariansyndrome,PCOS)患者与健康对照间肠道菌群谱结构特征差异,并探讨多囊卵巢综合征患者差异菌群与生化免疫指标之间的联系。【方法】选取初诊多囊卵巢综合征患者23例和健康女性对照23例,每例患者于初诊时留取粪便标本和血液标本,粪便标本提取DNA进行宏基因组测序,血清用于检测性激素和炎症因子。通过生物信息分析比较多囊卵巢综合征患者与健康对照间肠道菌群谱结构特征差异,以及与相关指标的联系。【结果】发现多囊卵巢综合征患者与健康对照的肠道菌群在门、属、种水平均有明显差异。两组间差异菌种为4个,普通拟杆菌(Bacteroides vulgatus)和弗格森埃希菌(Escherichia fergusonii)在PCOS组中的相对丰度高于对照组,并且这两种菌与PCOS的发病机制密切相关。凸腹真杆菌(Eubacteriumventriosum)和Subdoligranulum unclassified菌的相对丰度低于健康对照组。其中普通拟杆菌、凸腹真杆菌和Subdoligranulum unclassified菌3个菌种彼此间存在相关性,差异菌种与生化免疫指标间也存在相关性。发现布鲁米球菌、棒状戈登菌、脱硫弧菌、凸腹真杆菌、斯特雷沃菌5个菌的组合在PCOS患者早期诊断中具有较好的诊断效能。基因分析发现,鸟苷核苷酸从头生物合成的超途径I基因通路在PCOS人群中富集。【结论】多囊卵巢综合征患者与对照组间的肠道菌群和生化免疫指标均具有差异,并具有一定相关性,为PCOS患者的综合性诊疗提供了方向。

外伤后首诊为眼眶肿物的嗅神经母细胞瘤一例

患者,女,10岁,因“右眼眶外伤后18d,眶下周肿胀15d”于我院就诊。患者18d前不慎碰伤右眼眶下周,随即出现眼眶周部疼痛、皮下淤青,无出血、视力下降、视物重影,无鼻出血,未行特殊处理。之后疼痛渐消失,15d前出现眶下周肿胀,不伴有疼痛、鼻出血,肿物逐渐生长,并出现视物重影,视力下降。曾就诊于当地医院,行眼眶CT平扫,提示:右眼眶内占位,上颌窦侵犯,伴骨质破坏。

Construction of chlorogenic acid-containing liposomes with prolonged antitumor immunity based on T cell regulation

As a potential cancer immunotherapeutic agent,chlorogenic acid(CHA)has entered phase II clinical trials in China as a lyophilized powder formulation for treating glioma.However,the in vivo instability of CHA necessitates daily intramuscular injections,resulting in patient noncompliance.In this study,CHA-phospholipid complex(PC)-containing PEGylated liposomes(CHA-PC PEG-Lipo,named as CPPL),with CHA-PC as the drug intermediate,were prepared to lower the administration frequency.CPPL demonstrated excellent physicochemical properties,enhanced tumor accumulation,and inhibited tumor growth even when the administration interval was prolonged to 4 days when compared to a CHA solution and CHA-PC loaded liposomes(CHA-PC Lipo,labeled as CPL),both of which only demonstrated antitumor efficacy with once-daily administration.Further evaluation of the in vivo antitumor immune mechanism suggested that the extended antitumor immune efficacy of CPPL could be attributed to its distinct immune-stimulating mechanism when compared with CHA solution and CPL,such as stimulating both CD4+and CD8+T cell infiltration,inhibiting myeloid-derived suppressor cell expression,reducing the expression of Th2 related factors,and notably,increasing the memory T cells in tumor tissues.This CHA-containing formulation could reduce the frequency of in vivo CHA administration during cancer treatment via T cells,especially memory T cell regulation.

First-principles study of methanol adsorption on heteroatom-doped phosphorene

First-principles calculations based on van der Waals(vdW) corrected density functional theory(DFT) are firstly employed to investigate the adsorption of methanol(CH_3OH) gas molecule on pristine and Xdoped phosphorene( =B, C, N and O). The CH_3OH gas molecule is placed on the top of different phosphorene surfaces, the whole adsorption systems are fully optimized by using Vienna ab initio simulation package(VASP). The calculation results demonstrate that both pristine and heteroatomdoped phosphorene are sensitive to CH_3OH gas molecule with a moderate adsorption energy and an excellent charge transfer. Among all the investigated adsorption configurations, CH_3OH gas molecule is physically absorbed on pristine phosphorene and heteroatom-doped phosphorene. The N and O doping improve the adsorption of phosphorene with CH_3OH gas molecule, while B and C doping are almost not beneficial compared to the pristine phosphorene. The results suggest that N-doped and O-doped phosphorene are ideal candidates used for CH_3OH gas sensing.

Multi-platform omics analysis reveals molecular signature for COVID-19 pathogenesis,prognosis and drug target discovery

Disease progression prediction and therapeutic drug target discovery for Coronavirus disease 2019(COVID-19)are particularly important,as there is still no effective strategy for severe COVID-19 patient treatment.Herein,we performed multi-platform omics analysis of serial plasma and urine samples collected from patients during the course of COVID-19.Integrative analyses of these omics data revealed several potential therapeutic targets,such as ANXA1 and CLEC3B.Molecular changes in plasma indicated dysregulation of macrophage and suppression of T cell functions in severe patients compared to those in non-severe patients.Further,we chose 25 important molecular signatures as potential biomarkers for the prediction of disease severity.The prediction power was validated using corresponding urine samples and plasma samples from new COVID-19 patient cohort,with AUC reached to 0.904 and 0.988,respectively.In conclusion,our omics data proposed not only potential therapeutic targets,but also biomarkers for understanding the pathogenesis of severe COVID-19.

Influence of Natural Fractures on Tight Oil Migration and Production: A Case Study of Permian Lucaogou Formation in Jimsar Sag, Junggar Basin, NW China

Natural fractures,as the main flow channels and important storage spaces,have significant effects on the migration,distribution,and accumulation of tight oil.According to outcrop,core,formation micro image(FMI),cast-thin-section,and scanning electron microscopy data from the tight reservoir within the Permian Lucaogou Formation of the Junggar Basin,tectonic fractures are prevalent in this formation mainly on micro to large scale.There are two types of fractures worth noticing:diagenetic fractures and overpressure-related fractures,primarily at micro to medium scale.The diagenetic fractures consist of bedding fractures,stylolites,intragranular fractures,grain-boundary fractures,and diagenetic shrinkage fractures.Through FMI interpretation and Monte Carlo method evaluation,the macro-fractures could be considered as migration channels,and the micro-fractures as larger pore throats that function as storage spaces.The bedding fractures formed earlier than all tectonic fractures,while the overpressure-related fractures formed in the Middle and Late Jurassic.The bedding fractures and stylolites function as the primary channels for horizontal migration of tight oil.The tectonic fractures can provide vertical migration channels and reservoir spaces for tight oil,and readjust the tight oil distribution.The overpressure-related fractures are fully filled with calcite,and hence,have little effect on hydrocarbon migration and storage capacity.The data on tight oil production shows that the density and aperture of fractures jointly determine the productivity of a tight reservoir.