Objective： To evaluate the efficacy and safety of icotinib hydrochloride in patients with advanced non-small cell lung cancer （NSCLC）. Methods： A total of 89 patients with stage IIIB or IV NSCLC received icotinib ...Objective： To evaluate the efficacy and safety of icotinib hydrochloride in patients with advanced non-small cell lung cancer （NSCLC）. Methods： A total of 89 patients with stage IIIB or IV NSCLC received icotinib at a dose of 125 mg administered 3 times a day. Icotinib treatment was continued until disease progression or development of unacceptable toxicity. Results： A total of 89 patients were assessable. In patients treated with icotinib, the overall response rate （RR） was 36.0% （32/89）, and the disease control rate （DCR） was 69.7% （62/89）. RR and DCR were significantly improved in patients with adenocarcinoma versus non-adenocarcinoma （P〈0.05）. The symptom improvement rate was 57.3% （51/89）, and the main symptoms improved were cough, pain, chest distress, dyspnea, and Eastern Cooperative Oncology Group performance status. The main toxic effects were rash [30/89 （33.7%）] and diarrhea [15/89 （16.9%）]. The level of toxicity was typically low. Conclusions： The use of icofinib hydrochloride in the treatment of advanced NSCLC is efficacious and safe, and its toxic effects are tolerable.展开更多
In the last few years, cloud computing as a new computing paradigm has gone through significant development, but it is also facing many problems. One of them is the cloud service selection problem. As increasingly boo...In the last few years, cloud computing as a new computing paradigm has gone through significant development, but it is also facing many problems. One of them is the cloud service selection problem. As increasingly boosting cloud services are offered through the internet and some of them may be not reliable or even malicious, how to select trustworthy cloud services for cloud users is a big challenge. In this paper, we propose a multi-dimensional trust-aware cloud service selection mechanism based on evidential reasoning(ER) approach that integrates both perception-based trust value and reputation based trust value, which are derived from direct and indirect trust evidence respectively, to identify trustworthy services. Here, multi-dimensional trust evidence, which reflects the trustworthiness of cloud services from different aspects, is elicited in the form of historical users feedback ratings. Then, the ER approach is applied to aggregate the multi-dimensional trust ratings to obtain the real-time trust value and select the most trustworthy cloud service of certain type for the active users. Finally, the fresh feedback from the active users will update the trust evidence for other service users in the future.展开更多
During the operational process of natural gas gathering and transmission pipelines,the formation of hydrates is highly probable,leading to uncontrolled movement and aggregation of hydrates.The continuous migration and...During the operational process of natural gas gathering and transmission pipelines,the formation of hydrates is highly probable,leading to uncontrolled movement and aggregation of hydrates.The continuous migration and accumulation of hydrates further contribute to the obstruction of natural gas pipelines,resulting in production reduction,shutdowns,and pressure build-ups.Consequently,a cascade of risks is prone to occur.To address this issue,this study focuses on the operational process of natural gas gathering and transmission pipelines,where a comprehensive framework is established.This framework includes theoretical models for pipeline temperature distribution,pipeline pressure distribution,multiphase flow within the pipeline,hydrate blockage,and numerical solution methods.By analyzing the influence of inlet temperature,inlet pressure,and terminal pressure on hydrate formation within the pipeline,the sensitivity patterns of hydrate blockage risks are derived.The research indicates that reducing inlet pressure and terminal pressure could lead to a decreased maximum hydrate formation rate,potentially mitigating pipeline blockage during natural gas transportation.Furthermore,an increase in inlet temperature and terminal pressure,and a decrease in inlet pressure,results in a displacement of the most probable location for hydrate blockage towards the terminal station.However,it is crucial to note that operating under low-pressure conditions significantly elevates energy consumption within the gathering system,contradicting the operational goal of energy efficiency and reduction of energy consumption.Consequently,for high-pressure gathering pipelines,measures such as raising the inlet temperature or employing inhibitors,electrical heat tracing,and thermal insulation should be adopted to prevent hydrate formation during natural gas transportation.Moreover,considering abnormal conditions such as gas well production and pipeline network shutdowns,which could potentially trigger hydrate formation,the installation of methanol injection connectors remains necessary to ensure production safety.展开更多
BiFeO_(3)-BaTiO_(3)(BF-BT)lead-free piezoelectric ceramics have high piezoelectricity and high Curie temperature(T_(C)),but the mixed-valence Fe ions and Bi^(3+)volatilization would promote the formation of Bi_(25)FeO...BiFeO_(3)-BaTiO_(3)(BF-BT)lead-free piezoelectric ceramics have high piezoelectricity and high Curie temperature(T_(C)),but the mixed-valence Fe ions and Bi^(3+)volatilization would promote the formation of Bi_(25)FeO_(40)/Bi_(2)Fe_(4)O_9 and oxygen vacancy,which greatly degrade the insulation properties required for polarization.In this study,it was found that the modification of BiAlO_(3)(BA)in BF-BT ceramics could effectively solve these problems,reducing the leakage current to 1×10^(-9)A·cm^(-2)and transiting the space charge-limited conduction to ohmic conduction.Because of the enhanced insulation properties and appropriate rhombohedral-pseudocubic phase ratio(C_R/C_(PC)),BF-BT-xBA ceramics in an optimized composition obtain enhanced piezoelectric performance:piezoelectric charge coefficient(d_(33))=196 pC·N^(-1),planar electromechanical coupling coefficient(k_(p))=31.1%,T_(C)=487℃and depolarization temperature(T_d)=250°C;unipolar strain(S_(uni))=0.17%and piezoelectric strain coefficient(d_(33)^(*))=335 pm·V^(-1)at 100℃.Especially,d_(33)exceeds 283 pC·N^(-1)at 233℃and d_(33)^(*)is 335 pm·V^(-1)at100℃,showing an excellent high-temperature piezoelectricity and high depolarization temperature.The results are attributed to the domain structure of rhombohedral-pseudocubic phase coexistence and its high-temperature switching behavior.This work provides a feasible and effective approach to improve the high temperature piezoelectric properties of BF-BT-xBA ceramics,making them more suitable for high temperature applications.展开更多
A novel photooxidative system for degrading toxic organic pollutants is reported.A new complex of Fe_2L_3（L = bis[2-hydroxybenzaldehyde]hydrazone） synthesized can efficiently activate hydrogen peroxide （H_2O_2） to...A novel photooxidative system for degrading toxic organic pollutants is reported.A new complex of Fe_2L_3（L = bis[2-hydroxybenzaldehyde]hydrazone） synthesized can efficiently activate hydrogen peroxide （H_2O_2） to oxidize and mineralize the target complexes rhodamine B（RhB） and methyl orange（MO） in aqueous media under ambient temperature and normal pressure and with visible light irradiation.展开更多
In this paper, the present patent situation of the daily chemical industry was analyzed. The development trends of China patent protection in daily chemical industry were analyzed including patent application trend, p...In this paper, the present patent situation of the daily chemical industry was analyzed. The development trends of China patent protection in daily chemical industry were analyzed including patent application trend, patent type and applicant type. As a leading enterprise, the patent protection situation of P＆G was analyzed, which is significant for domestic enterprises. Finally, suggestions for China daily chemical industry were given according to the analysis results and experiences of the leading company from the perspective of patent protection.展开更多
Renal ischemia-reperfusion injury (IRI) is one of the major causes of acute kidney injury, and the inflammatory response is considered a key factor. The selenoprotein GPX3, a member of the glutathione peroxidase famil...Renal ischemia-reperfusion injury (IRI) is one of the major causes of acute kidney injury, and the inflammatory response is considered a key factor. The selenoprotein GPX3, a member of the glutathione peroxidase family, has gradually attracted attention for its anti-inflammatory properties. However, the relationship between GPX3 and the inflammatory response during renal IRI remains unclear. The present study aims to investigate the role of GPX3 on the inflammatory response during renal IRI and related mechanisms. We utilized classic rat models of kidney IRI and cellular hypoxia reoxygenation model. After overexpressing GPX3 via lentiviruses and adeno-associated viruses, we observed a significant reduction in the expression levels of inflammatory factors in renal tissues, along with an increase in the expression of anti-inflammatory factor IL-10, resulting in noticeable alleviation of renal IRI. Meanwhile, we found that GPX3 alleviated the inflammatory response, probably by inhibiting the MAPK signaling pathway and reducing the expression of NAPDH oxidase. To further validate the mechanism by which GPX3 alleviated the inflammatory response, we used the MAPK signaling pathway agonist anisomycin for intervention. The results showed that anisomycin intervention significantly reversed the inhibitory effect of GPX3 on the MAPK signaling pathway, in which the expression level of NADPH oxidase was significantly increased, the secretion of inflammatory factors was increased, and the degree of renal tissue damage was significantly increased. These findings suggest that selenoprotein GPX3 alleviates inflammation during renal IRI by inhibiting the MAPK signaling pathway and reducing NADPH oxidase expression.展开更多
Thermoelectric materials,which directly convert heat into electricity based on the Seebeck effects,have long been investigated for use in semiconductor refrigeration or waste heat recovery.Among them,SnSe has attracte...Thermoelectric materials,which directly convert heat into electricity based on the Seebeck effects,have long been investigated for use in semiconductor refrigeration or waste heat recovery.Among them,SnSe has attracted significant attention due to its promising performance in both p-type and n-type crystals;in particular,a higher out-of-plane ZT value could be achieved in ntype SnSe due to its 3D charge and 2D phonon transports.In this work,the thermoelectric transport properties of n-type polycrystalline SnSe were investigated with an emphasis on the out-of-plane transport through producing textural microstructure.The textures were fabricated using mechanical alloying and repeated spark plasma sintering(SPS),as a kind of hot pressing,aimed at producing strong anisotropic transports in n-type polycrystalline SnSe as that in crystalline SnSe.Results show that the lowest thermal conductivity of 0.36 Wm^(-1) K^(-1) was obtained at 783 K in perpendicular to texture direction.Interestingly,the electrical transport properties are less anisotropic and even nearly isotropic,and the power factors reach 681.3μWm^(-1) K^(-2) at 783 K along both parallel and perpendicular directions.The combination of large isotropic power factor and low anisotropic thermal conductivity leads to a maximum ZT of 1.5 at 783 K.The high performance elucidates the outstanding electrical and thermal transport behaviors in n-type polycrystalline SnSe,and a higher thermoelectric performance can be expected with future optimizing texture in n-type polycrystalline SnSe.展开更多
Cu_(1.8)S has been considered as a potential thermoelectric(TE)material for its stable electrical and thermal properties,environmental benignity,and low cost.Herein,the TE properties of nanostructured Cu_(1.8)S_(1-x)T...Cu_(1.8)S has been considered as a potential thermoelectric(TE)material for its stable electrical and thermal properties,environmental benignity,and low cost.Herein,the TE properties of nanostructured Cu_(1.8)S_(1-x)Te_(x)(0≤x≤0.2)bulks fabricated by a facile process combining mechanical alloying(MA)and room-temperature high-pressure sintering(RT-HPS)technique were optimized via eliminating the volatilization of S element and suppressing grain growth.Experimentally,a single phase of Cu_(1.8)S was obtained at x=0,and a second Cu_(1.96)S phase formed in all Cu_(1.8)S_(1-x)Te_(x) samples when 0.05≤x≤0.125.With further increasing x to 0.15≤x≤0.2,the Cu_(2-z)Te phase was detected and the samples consisted of Cu_(1.8)S,Cu_(1.96)S,and Cu_(2-z)Te phases.Benefiting from a modified band structure and the coexisted phases of Cu_(1.96)S and Cu_(2-z)Te,the power factor is enhanced in all Cu_(1.8)S_(1-x)Te_(x)(0.05≤x≤0.2)alloys.Combining with a drastic decrease in the thermal conductivity due to the strengthened phonon scatterings from multiscale defects introduced by Te doping and nano-grain boundaries,a maximum figure of merit(ZT)of 0.352 is reached at 623 K for Cu_(1.8)S_(0.875)Te_(0.125),which is 171%higher than that of Cu_(1.8)S(0.130).The study demonstrates that doping Te is an effective strategy to improve the TE performance of Cu_(1.8)S based materials and the proposed facile method combing MA and RT-HPS is a potential way to fabricate nanostructured bulks.展开更多
Seed-mediated growth is the most general way to controllably synthesize bimetal nano-heterostructures. Despite successful instances through trial and error were reported, the way for second metal depositing on the see...Seed-mediated growth is the most general way to controllably synthesize bimetal nano-heterostructures. Despite successful instances through trial and error were reported, the way for second metal depositing on the seed. namely whether the symmetry of resulted nano-heterostructure follows the original crystal symmetry of seed metal, remains an unpredictable issue to date. In this work, we propose that the ther- modynamic factor, i.e., the difference of equilibrium electrochemical potentials （corresponding to their Fermi levels） of two metals in the growth solution, plays a key role for the symmetry breaking of bimetal nano-heterostructures during the seed-mediated growth. As a proof-of-principle experiment, by revers- ing the relative position of Fermi levels of the Pd nanocube seeds and the second metal Au with changing the concentration of reductant （L-ascorbic acid） in the growth solution, the structure of as-prepared prod- ucts successfully evolved from centrosymmetric Pd@Au core-shell trisoctabedra to asymmetric Pd-Au hetero-dimers. The idea was further demonstrated by the growth of Ag on the Pd seeds. The present work intends to reveal the origin of symmetry breaking in the seed-mediated growth of nano-heterostructures from the viewpoint of thermodynamics, and these new insights will in turn help to achieve rational con- struction of bimetal nano-heterostructures with soecific functions.展开更多
Digenite(Cu_(1.8)S)as a potential p-type thermoelectric(TE)material has attracted extensive attention due to its environmental benign,abundant resources and low cost of component elements.In this study,the TE properti...Digenite(Cu_(1.8)S)as a potential p-type thermoelectric(TE)material has attracted extensive attention due to its environmental benign,abundant resources and low cost of component elements.In this study,the TE properties of MnxCu_(1.8)S bulk samples prepared by mechanical alloying(MA)combined with spark plasma sintering(SPS)were investigated.Doping Mn would initially substitute Cu and tune the band structure of Cu1.8S with an enlarged band gap Eg.However,if Mn content is beyond the solubility limit of x=0.01 in Cu1.8S will cause the formation of MnS,which contributes to the formation of Cu-rich phases at 0.02 ≤x≤ 0.08.Benefiting from the synergetic scattering effect of point defects(Mn Cu,V_(S))and MnS,Cu1.96S,Cu1.97S,Cu2S phases,the lowest thermal conductivity k value of 0.75 W m^(-1) K^(-1) was obtained at 773 K for Mn0.08Cu1.8S.Along with the decreased k,the highest figure of merit ZT value of 0.92 at 773 K achieved in Mn0.08Cu1.8S bulk sample.A maximum engineering ZTeng of 0.3 and its efficiency hmax of about 6%were obtained at 323e773 K,which is almost 3 times than that of the pristine Cu1.8S(ηmax=2.2%).Introducing Mn in Cu1.8S is an effective and convenient strategy to improve TE performance.展开更多
BiFeO_(3)–BaTiO_(3)(BF–BT)based piezoelectric ceramics are a kind of high-temperature lead-free piezoelectric ceramics with great development prospects due to their high Curie temperature(TC)and excellent electrical...BiFeO_(3)–BaTiO_(3)(BF–BT)based piezoelectric ceramics are a kind of high-temperature lead-free piezoelectric ceramics with great development prospects due to their high Curie temperature(TC)and excellent electrical properties.However,large leakage current limits their performance improvement and practical applications.In this work,direct current(DC)test,alternating current(AC)impedance,and Hall tests were used to investigate conduction mechanisms of 0.75BiFeO_(3)–0.25BaTiO_(3)ceramics over a wide temperature range.In the range of room temperature(RT)−150℃,ohmic conduction plays a predominant effect,and the main carriers are p-type holes with the activation energy(Ea)of 0.51 eV.When T>200℃,the Ea value calculated from the AC impedance and Hall data is 1.03 eV with oxygen vacancies as a cause of high conductivity.The diffusion behavior of thermally activated oxygen vacancies is affected by crystal symmetry,oxygen vacancy concentration,and distribution,dominating internal conduction mechanism.Deciphering the conduction mechanisms over the three temperature ranges would pave the way for further improving the insulation and electrical properties of BiFeO_(3)–BaTiO_(3)ceramics.展开更多
BiFeO_(3)-BaTiO_(3) based ceramics are considered to be the most promising lead-free piezoelectric ceramics due to their large piezoelectric response and high Curie temperature.Since the piezoelectric response of piez...BiFeO_(3)-BaTiO_(3) based ceramics are considered to be the most promising lead-free piezoelectric ceramics due to their large piezoelectric response and high Curie temperature.Since the piezoelectric response of piezoelectric ceramics just appears after poling engineering,in this work,the domain evolution and microscopic piezoresponse were observed in-situ using piezoresponse force microscopy(PFM)and switching spectroscopy piezoresponse force microscopy(SS-PFM),which can effectively study the local switching characteristics of ferroelectric materials especially at the nanoscale.The new domain nucleation preferentially forms at the boundary of the relative polarization region and expands laterally with the increase of bias voltage and temperature.The maximum piezoresponse(Rs),remnant piezoresponse(Rrem),maximum displacement(Dmax)and negative displacement(Dneg)at 45 V and 120C reach 122,69,127 pm and 75 pm,respectively.Due to the distinct effect of poling engineering in full domain switching,the corresponding d33 at 50 kV/cm and 120C reaches a maximum of 205 pC/N,which is nearly twice as high as that at room temperature.Studying the evolution of ferroelectric domains in the poling engineering of BiFeO_(3)-BaTiO_(3)ceramics provides an insight into the relationship between domain structure and piezoelectric response,which has implications for other piezoelectric ceramics as well.展开更多
There are many emergency risks in the process of natural gas hydrate(NGH)drilling.In order to ensure the safe and efficient exploitation of NGH,it is urgent to establish an intelligent judgment method for the risks in...There are many emergency risks in the process of natural gas hydrate(NGH)drilling.In order to ensure the safe and efficient exploitation of NGH,it is urgent to establish an intelligent judgment method for the risks in the process of NGH drilling.In this paper,the response relationship between monitoring parameters and risk categories of NGH while drilling is established.Based on fuzzy analytic hierarchy process(FAHP),the comprehensive weights of 10 risk monitoring parameters are obtained,including gas production,wellbore instability,hydrate ice barrier,drill string fracture,sticking,bit balling,drilling tool piercement,gas seepage,seabed subsidence and seabed landslide.Besides,the comprehensive judgment weight matrix is constructed,and the reasonable fluctuation range of monitoring parameters is formed.Thus,the intelligent judgment method of NGH drilling risk is established.The intelligent judgment and alarm of NGH drilling risks can be realized quickly and accurately by this method,namely,it can monitor the risks in the process of operation and guarantee the construction safety of NGH drilling.展开更多
Isobaric specific heat capacity(Cp)is an important parameter not only in physics but also for most materials.Its accurate measurement is particularly critical for performance evaluation of thermoelectric materials,but...Isobaric specific heat capacity(Cp)is an important parameter not only in physics but also for most materials.Its accurate measurement is particularly critical for performance evaluation of thermoelectric materials,but the experiments by differential scanning calorimetry(DSC)often lead to large uncertainties in the measurements,especially at elevated temperatures.In this study,we propose a simple method to determine Cp by measuring the sound velocity(υ)based on lattice vibration and expansion theory.The relative standard error of theυis smaller than 1%,showing good accuracy and repeatability.The calculated Cp at elevated temperature(>300 K)increases slightly with increasing temperature due to the lattice expansion,which is more reasonable than the Dulong–Petit value.展开更多
无污染、低成本和高性能Cu_(1.8)S基类液态热电材料受到关注.但是,其过高的本征Cu空位和Cu离子迁移特性限制了其性能和电稳定性的进一步提升.本研究采用机械合金化结合放电等离子体烧结制备了一系列Cu_(1.8)S和Mn_(x)Cu_(1.8)S_(0.5)Se_...无污染、低成本和高性能Cu_(1.8)S基类液态热电材料受到关注.但是,其过高的本征Cu空位和Cu离子迁移特性限制了其性能和电稳定性的进一步提升.本研究采用机械合金化结合放电等离子体烧结制备了一系列Cu_(1.8)S和Mn_(x)Cu_(1.8)S_(0.5)Se_(0.5)(0.01≤x≤0.06)块体热电材料.随着Se和Mn的引入,体系由低熵Cu_(1.8)S(0.4R^(*))转变为中熵MnxCu_(1.8)S_(0.5)Se_(0.5)(1.2R^(*)).构型熵的增加不仅提高了体系的结构对称性,MnxCu_(1.8)S_(0.5)Se_(0.5)室温下呈立方相结构,还增大了Mn的固溶度.高浓度Mn固溶有效填补了过高的本征Cu空位,降低了载流子浓度,优化了能带结构,提升了电输运性能.熵工程一方面增大了Cu离子迁移势垒,抑制Cu离子迁移.750 K下,即使电流密度达到24 A cm^(-2),Mn_(0.03)Cu_(1.8)S_(0.5)Se_(0.5)的电阻也几乎没有变化,显示出优异的电稳定性;同时可降低声速,软化晶格,降低晶格热导率.Mn_(0.06)Cu_(1.8)S_(0.5)Se_(0.5)的块体样品在773 K时获得最大ZT值0.79,相较于初始样品提高了两倍.结果表明熵工程结合Cu空位工程是提升Cu_(1.8)S基热电材料性能的有效策略.展开更多
Fabrication of nanoparticle-dispersed composites is an effective strategy for enhancing the performance of thermoelectric materials,and in particular SiC nanoparticles have been often used to create composites with Bi...Fabrication of nanoparticle-dispersed composites is an effective strategy for enhancing the performance of thermoelectric materials,and in particular SiC nanoparticles have been often used to create composites with Bi_(2)Te_(3)-based applied thermoelectric materials.However,the effect of particle size on the thermoelectric performance is unclear.This work systematically investigated the electrical and thermal properties of a series of(Bi,Sb)_(2)Te_(3)-based nanocomposites containing dispersed SiC nanoparticles of different sizes.It was found that particle size has a significant impact on the electrical properties with smaller SiC nanoparticles giving rise to higher electrical conductivity.Even though the dispersed SiC nanoparticles enhanced the Seebeck coefficient,no apparent dependence of the enhancement on the particle size was observed.It was also found that smaller SiC nanoparticles scatter phonons to some extent while the larger nanoparticles contribute to increased thermal conductivity.Eventually,the highest ZT value of 1.12 was obtained in 30 nm-SiC dispersed sample,corresponding to an increase by 18%from 0.95 for the matrix made from commercial scraps,and then the ZT was further boosted to 1.33 by optimizing the matrix composition and expelling excess Te during the optimized spark plasma sintering process.This work proves that the dispersion of smaller SiC nanoparticles in p-type(Bi,Sb)_(2)Te_(3) materials is more effective than the dispersion of larger nanoparticles.In addition,it is revealed that additional compositional and/or processing optimization is vital and effective for obtaining further performance enhancement for nanocomposites of SiC nanoparticles dispersed in(Bi,Sb)_(2)Te_(3).展开更多
In this paper, we establish a Hua-Like theorem in some kind of semirings. This can be regarded as a generalized version of Hua＇s theorem from rings to semirings.
Extremely low lattice thermal conductivity is always the pursuit of thermoelectric materials research.In this work,we reported an exceptional effect of Ag2S addition in MnTe,an emerging promising midtemperature thermo...Extremely low lattice thermal conductivity is always the pursuit of thermoelectric materials research.In this work,we reported an exceptional effect of Ag2S addition in MnTe,an emerging promising midtemperature thermoelectric material,to enable the realization of minimum lattice thermal conductivity,namely-0.4 Wm^(-1) K^(-1).Such a low lattice thermal conductivity is guaranteed by the incorporation of in-situ formed Ag rich phase(Ag2Te)with ultralow lattice thermal conductivity and further scattering of phonons from the partial doping effects induced point defects and boundaries between various phases.Apart from the dramatically decreased lattice thermal conductivity,the partial doping of Ag and S simultaneously enhance the electrical conductivity,further contributing to enhanced thermoelectric performance.Meanwhile,an inverse sign of Seebeck and Hall coefficient was observed and rationalized by the influence of highly electron-conductive Ag_(2)Te phase.Thanks to the synergetic modulation of electrical and thermal transport properties by in-situ formed composite,a high ZT value of 1.1 was achieved in MnTe based thermoelectric materials,which also demonstrates the importance of compositing approaches to design state-of-the-art thermoelectric materials.展开更多
It is easy to change the original temperature state of marine gas hydrate reservoir by drilling,which leads to uncontrollable decomposition of gas hydrate and release of large amount of gas.The decomposition gas will ...It is easy to change the original temperature state of marine gas hydrate reservoir by drilling,which leads to uncontrollable decomposition of gas hydrate and release of large amount of gas.The decomposition gas will further escape and expand,and the reservoir will break and collapse due to its weak cementation characteristic,which will easily lead to a series of other potential risks.Therefore,in this study,based on the drilling process of marine gas hydrate,we establish the theoretical model and numerical calculation method of wellbore temperature field,analyze the influence on wellbore temperature of drilling fluid displacement,density,viscosity and injection temperature,and seawater depth.Then the sensitivity laws of reservoir risk in marine gas hydrate drilling are obtained.The results show that with the increase of drilling fluid displacement,density,viscosity and injection temperature,the temperature in lower well section and bottom hole will increase,making the increasing amplitude of temperature in hydrate reservoir larger and the scope of influence on hydrate reservoir stability bigger.Moreover,drilling is more likely to raise the temperature of reservoirs in shallow seawater depth,posing greater risks.Thus,engineering measures to avoid risks caused by rising reservoir temperature in marine gas hydrate reservoir drilling are presented.This study is of great significance to ensure the safety of marine gas hydrate reservoir drilling.展开更多
文摘Objective： To evaluate the efficacy and safety of icotinib hydrochloride in patients with advanced non-small cell lung cancer （NSCLC）. Methods： A total of 89 patients with stage IIIB or IV NSCLC received icotinib at a dose of 125 mg administered 3 times a day. Icotinib treatment was continued until disease progression or development of unacceptable toxicity. Results： A total of 89 patients were assessable. In patients treated with icotinib, the overall response rate （RR） was 36.0% （32/89）, and the disease control rate （DCR） was 69.7% （62/89）. RR and DCR were significantly improved in patients with adenocarcinoma versus non-adenocarcinoma （P〈0.05）. The symptom improvement rate was 57.3% （51/89）, and the main symptoms improved were cough, pain, chest distress, dyspnea, and Eastern Cooperative Oncology Group performance status. The main toxic effects were rash [30/89 （33.7%）] and diarrhea [15/89 （16.9%）]. The level of toxicity was typically low. Conclusions： The use of icofinib hydrochloride in the treatment of advanced NSCLC is efficacious and safe, and its toxic effects are tolerable.
基金supported by National Natural Science Foundation of China(Nos.71131002,71071045,71231004 and 71201042)
文摘In the last few years, cloud computing as a new computing paradigm has gone through significant development, but it is also facing many problems. One of them is the cloud service selection problem. As increasingly boosting cloud services are offered through the internet and some of them may be not reliable or even malicious, how to select trustworthy cloud services for cloud users is a big challenge. In this paper, we propose a multi-dimensional trust-aware cloud service selection mechanism based on evidential reasoning(ER) approach that integrates both perception-based trust value and reputation based trust value, which are derived from direct and indirect trust evidence respectively, to identify trustworthy services. Here, multi-dimensional trust evidence, which reflects the trustworthiness of cloud services from different aspects, is elicited in the form of historical users feedback ratings. Then, the ER approach is applied to aggregate the multi-dimensional trust ratings to obtain the real-time trust value and select the most trustworthy cloud service of certain type for the active users. Finally, the fresh feedback from the active users will update the trust evidence for other service users in the future.
基金supported by 111 Project (No.D21025)Open Fund Project of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Nos.PLN2021-01,PLN2021-02,PLN2021-03)+2 种基金High-end Foreign Expert Introduction Program (No.G2021036005L)National Key Research and Development Program (No.2021YFC2800903)National Natural Science Foundation of China (No.U20B6005-05)。
文摘During the operational process of natural gas gathering and transmission pipelines,the formation of hydrates is highly probable,leading to uncontrolled movement and aggregation of hydrates.The continuous migration and accumulation of hydrates further contribute to the obstruction of natural gas pipelines,resulting in production reduction,shutdowns,and pressure build-ups.Consequently,a cascade of risks is prone to occur.To address this issue,this study focuses on the operational process of natural gas gathering and transmission pipelines,where a comprehensive framework is established.This framework includes theoretical models for pipeline temperature distribution,pipeline pressure distribution,multiphase flow within the pipeline,hydrate blockage,and numerical solution methods.By analyzing the influence of inlet temperature,inlet pressure,and terminal pressure on hydrate formation within the pipeline,the sensitivity patterns of hydrate blockage risks are derived.The research indicates that reducing inlet pressure and terminal pressure could lead to a decreased maximum hydrate formation rate,potentially mitigating pipeline blockage during natural gas transportation.Furthermore,an increase in inlet temperature and terminal pressure,and a decrease in inlet pressure,results in a displacement of the most probable location for hydrate blockage towards the terminal station.However,it is crucial to note that operating under low-pressure conditions significantly elevates energy consumption within the gathering system,contradicting the operational goal of energy efficiency and reduction of energy consumption.Consequently,for high-pressure gathering pipelines,measures such as raising the inlet temperature or employing inhibitors,electrical heat tracing,and thermal insulation should be adopted to prevent hydrate formation during natural gas transportation.Moreover,considering abnormal conditions such as gas well production and pipeline network shutdowns,which could potentially trigger hydrate formation,the installation of methanol injection connectors remains necessary to ensure production safety.
基金financially supported by the National Natural Science Foundation of China (Nos.52072028 and52032007)National Key Research and Development Program (No.2022YFB3807400)。
文摘BiFeO_(3)-BaTiO_(3)(BF-BT)lead-free piezoelectric ceramics have high piezoelectricity and high Curie temperature(T_(C)),but the mixed-valence Fe ions and Bi^(3+)volatilization would promote the formation of Bi_(25)FeO_(40)/Bi_(2)Fe_(4)O_9 and oxygen vacancy,which greatly degrade the insulation properties required for polarization.In this study,it was found that the modification of BiAlO_(3)(BA)in BF-BT ceramics could effectively solve these problems,reducing the leakage current to 1×10^(-9)A·cm^(-2)and transiting the space charge-limited conduction to ohmic conduction.Because of the enhanced insulation properties and appropriate rhombohedral-pseudocubic phase ratio(C_R/C_(PC)),BF-BT-xBA ceramics in an optimized composition obtain enhanced piezoelectric performance:piezoelectric charge coefficient(d_(33))=196 pC·N^(-1),planar electromechanical coupling coefficient(k_(p))=31.1%,T_(C)=487℃and depolarization temperature(T_d)=250°C;unipolar strain(S_(uni))=0.17%and piezoelectric strain coefficient(d_(33)^(*))=335 pm·V^(-1)at 100℃.Especially,d_(33)exceeds 283 pC·N^(-1)at 233℃and d_(33)^(*)is 335 pm·V^(-1)at100℃,showing an excellent high-temperature piezoelectricity and high depolarization temperature.The results are attributed to the domain structure of rhombohedral-pseudocubic phase coexistence and its high-temperature switching behavior.This work provides a feasible and effective approach to improve the high temperature piezoelectric properties of BF-BT-xBA ceramics,making them more suitable for high temperature applications.
文摘A novel photooxidative system for degrading toxic organic pollutants is reported.A new complex of Fe_2L_3（L = bis[2-hydroxybenzaldehyde]hydrazone） synthesized can efficiently activate hydrogen peroxide （H_2O_2） to oxidize and mineralize the target complexes rhodamine B（RhB） and methyl orange（MO） in aqueous media under ambient temperature and normal pressure and with visible light irradiation.
文摘In this paper, the present patent situation of the daily chemical industry was analyzed. The development trends of China patent protection in daily chemical industry were analyzed including patent application trend, patent type and applicant type. As a leading enterprise, the patent protection situation of P＆G was analyzed, which is significant for domestic enterprises. Finally, suggestions for China daily chemical industry were given according to the analysis results and experiences of the leading company from the perspective of patent protection.
基金supported by the Chongqing Natural Science Foundation Innovation and Development Joint Fund Project(China)(No.CSTB2024NSCQ-LZX0072)the Program for Youth Innovation in Future Medicine,Chongqing Medical University(China)(No.W0201)The Joint Medical Research Project of Chongqing Science and Technology Bureau and Health Commission(China)(No.2024MSXM002).
文摘Renal ischemia-reperfusion injury (IRI) is one of the major causes of acute kidney injury, and the inflammatory response is considered a key factor. The selenoprotein GPX3, a member of the glutathione peroxidase family, has gradually attracted attention for its anti-inflammatory properties. However, the relationship between GPX3 and the inflammatory response during renal IRI remains unclear. The present study aims to investigate the role of GPX3 on the inflammatory response during renal IRI and related mechanisms. We utilized classic rat models of kidney IRI and cellular hypoxia reoxygenation model. After overexpressing GPX3 via lentiviruses and adeno-associated viruses, we observed a significant reduction in the expression levels of inflammatory factors in renal tissues, along with an increase in the expression of anti-inflammatory factor IL-10, resulting in noticeable alleviation of renal IRI. Meanwhile, we found that GPX3 alleviated the inflammatory response, probably by inhibiting the MAPK signaling pathway and reducing the expression of NAPDH oxidase. To further validate the mechanism by which GPX3 alleviated the inflammatory response, we used the MAPK signaling pathway agonist anisomycin for intervention. The results showed that anisomycin intervention significantly reversed the inhibitory effect of GPX3 on the MAPK signaling pathway, in which the expression level of NADPH oxidase was significantly increased, the secretion of inflammatory factors was increased, and the degree of renal tissue damage was significantly increased. These findings suggest that selenoprotein GPX3 alleviates inflammation during renal IRI by inhibiting the MAPK signaling pathway and reducing NADPH oxidase expression.
基金This work was supported by the Basic Science Center Project of NSFC under Grant No.51788104the National Key R&D Program of China(Grant No.2018YFB0703603).
文摘Thermoelectric materials,which directly convert heat into electricity based on the Seebeck effects,have long been investigated for use in semiconductor refrigeration or waste heat recovery.Among them,SnSe has attracted significant attention due to its promising performance in both p-type and n-type crystals;in particular,a higher out-of-plane ZT value could be achieved in ntype SnSe due to its 3D charge and 2D phonon transports.In this work,the thermoelectric transport properties of n-type polycrystalline SnSe were investigated with an emphasis on the out-of-plane transport through producing textural microstructure.The textures were fabricated using mechanical alloying and repeated spark plasma sintering(SPS),as a kind of hot pressing,aimed at producing strong anisotropic transports in n-type polycrystalline SnSe as that in crystalline SnSe.Results show that the lowest thermal conductivity of 0.36 Wm^(-1) K^(-1) was obtained at 783 K in perpendicular to texture direction.Interestingly,the electrical transport properties are less anisotropic and even nearly isotropic,and the power factors reach 681.3μWm^(-1) K^(-2) at 783 K along both parallel and perpendicular directions.The combination of large isotropic power factor and low anisotropic thermal conductivity leads to a maximum ZT of 1.5 at 783 K.The high performance elucidates the outstanding electrical and thermal transport behaviors in n-type polycrystalline SnSe,and a higher thermoelectric performance can be expected with future optimizing texture in n-type polycrystalline SnSe.
基金supported by the National Key R&D Program of China(Grant No.2018YFB0703600)the National Natural Science Foundation of China(Grant No.11474176).
文摘Cu_(1.8)S has been considered as a potential thermoelectric(TE)material for its stable electrical and thermal properties,environmental benignity,and low cost.Herein,the TE properties of nanostructured Cu_(1.8)S_(1-x)Te_(x)(0≤x≤0.2)bulks fabricated by a facile process combining mechanical alloying(MA)and room-temperature high-pressure sintering(RT-HPS)technique were optimized via eliminating the volatilization of S element and suppressing grain growth.Experimentally,a single phase of Cu_(1.8)S was obtained at x=0,and a second Cu_(1.96)S phase formed in all Cu_(1.8)S_(1-x)Te_(x) samples when 0.05≤x≤0.125.With further increasing x to 0.15≤x≤0.2,the Cu_(2-z)Te phase was detected and the samples consisted of Cu_(1.8)S,Cu_(1.96)S,and Cu_(2-z)Te phases.Benefiting from a modified band structure and the coexisted phases of Cu_(1.96)S and Cu_(2-z)Te,the power factor is enhanced in all Cu_(1.8)S_(1-x)Te_(x)(0.05≤x≤0.2)alloys.Combining with a drastic decrease in the thermal conductivity due to the strengthened phonon scatterings from multiscale defects introduced by Te doping and nano-grain boundaries,a maximum figure of merit(ZT)of 0.352 is reached at 623 K for Cu_(1.8)S_(0.875)Te_(0.125),which is 171%higher than that of Cu_(1.8)S(0.130).The study demonstrates that doping Te is an effective strategy to improve the TE performance of Cu_(1.8)S based materials and the proposed facile method combing MA and RT-HPS is a potential way to fabricate nanostructured bulks.
基金supported by the National Basic Research Program of China(2015CB93230)the National Key Research and Development Program of China(2017YFA0206801)+1 种基金the National Natural Science Foundation of China(21333008,21671163,21721001,and 21773190)the Fundamental Research Funds for the Central Universities(20720160026)
文摘Seed-mediated growth is the most general way to controllably synthesize bimetal nano-heterostructures. Despite successful instances through trial and error were reported, the way for second metal depositing on the seed. namely whether the symmetry of resulted nano-heterostructure follows the original crystal symmetry of seed metal, remains an unpredictable issue to date. In this work, we propose that the ther- modynamic factor, i.e., the difference of equilibrium electrochemical potentials （corresponding to their Fermi levels） of two metals in the growth solution, plays a key role for the symmetry breaking of bimetal nano-heterostructures during the seed-mediated growth. As a proof-of-principle experiment, by revers- ing the relative position of Fermi levels of the Pd nanocube seeds and the second metal Au with changing the concentration of reductant （L-ascorbic acid） in the growth solution, the structure of as-prepared prod- ucts successfully evolved from centrosymmetric Pd@Au core-shell trisoctabedra to asymmetric Pd-Au hetero-dimers. The idea was further demonstrated by the growth of Ag on the Pd seeds. The present work intends to reveal the origin of symmetry breaking in the seed-mediated growth of nano-heterostructures from the viewpoint of thermodynamics, and these new insights will in turn help to achieve rational con- struction of bimetal nano-heterostructures with soecific functions.
基金supported by National Key R&D Program of China(Grant No.2018YFB0703600)the National Natural Science Foundation of China(Grant No.11474176)。
文摘Digenite(Cu_(1.8)S)as a potential p-type thermoelectric(TE)material has attracted extensive attention due to its environmental benign,abundant resources and low cost of component elements.In this study,the TE properties of MnxCu_(1.8)S bulk samples prepared by mechanical alloying(MA)combined with spark plasma sintering(SPS)were investigated.Doping Mn would initially substitute Cu and tune the band structure of Cu1.8S with an enlarged band gap Eg.However,if Mn content is beyond the solubility limit of x=0.01 in Cu1.8S will cause the formation of MnS,which contributes to the formation of Cu-rich phases at 0.02 ≤x≤ 0.08.Benefiting from the synergetic scattering effect of point defects(Mn Cu,V_(S))and MnS,Cu1.96S,Cu1.97S,Cu2S phases,the lowest thermal conductivity k value of 0.75 W m^(-1) K^(-1) was obtained at 773 K for Mn0.08Cu1.8S.Along with the decreased k,the highest figure of merit ZT value of 0.92 at 773 K achieved in Mn0.08Cu1.8S bulk sample.A maximum engineering ZTeng of 0.3 and its efficiency hmax of about 6%were obtained at 323e773 K,which is almost 3 times than that of the pristine Cu1.8S(ηmax=2.2%).Introducing Mn in Cu1.8S is an effective and convenient strategy to improve TE performance.
基金supported by the National Natural Science Foundation of China(Nos.52072028,52032007)National Key R&D Program of China(No.2022YFB3807400).
文摘BiFeO_(3)–BaTiO_(3)(BF–BT)based piezoelectric ceramics are a kind of high-temperature lead-free piezoelectric ceramics with great development prospects due to their high Curie temperature(TC)and excellent electrical properties.However,large leakage current limits their performance improvement and practical applications.In this work,direct current(DC)test,alternating current(AC)impedance,and Hall tests were used to investigate conduction mechanisms of 0.75BiFeO_(3)–0.25BaTiO_(3)ceramics over a wide temperature range.In the range of room temperature(RT)−150℃,ohmic conduction plays a predominant effect,and the main carriers are p-type holes with the activation energy(Ea)of 0.51 eV.When T>200℃,the Ea value calculated from the AC impedance and Hall data is 1.03 eV with oxygen vacancies as a cause of high conductivity.The diffusion behavior of thermally activated oxygen vacancies is affected by crystal symmetry,oxygen vacancy concentration,and distribution,dominating internal conduction mechanism.Deciphering the conduction mechanisms over the three temperature ranges would pave the way for further improving the insulation and electrical properties of BiFeO_(3)–BaTiO_(3)ceramics.
基金supported by the National Natural Science Foundation of China(52072028 and 52032007)the National Key Research and Development Program(2022YFB3807400).
文摘BiFeO_(3)-BaTiO_(3) based ceramics are considered to be the most promising lead-free piezoelectric ceramics due to their large piezoelectric response and high Curie temperature.Since the piezoelectric response of piezoelectric ceramics just appears after poling engineering,in this work,the domain evolution and microscopic piezoresponse were observed in-situ using piezoresponse force microscopy(PFM)and switching spectroscopy piezoresponse force microscopy(SS-PFM),which can effectively study the local switching characteristics of ferroelectric materials especially at the nanoscale.The new domain nucleation preferentially forms at the boundary of the relative polarization region and expands laterally with the increase of bias voltage and temperature.The maximum piezoresponse(Rs),remnant piezoresponse(Rrem),maximum displacement(Dmax)and negative displacement(Dneg)at 45 V and 120C reach 122,69,127 pm and 75 pm,respectively.Due to the distinct effect of poling engineering in full domain switching,the corresponding d33 at 50 kV/cm and 120C reaches a maximum of 205 pC/N,which is nearly twice as high as that at room temperature.Studying the evolution of ferroelectric domains in the poling engineering of BiFeO_(3)-BaTiO_(3)ceramics provides an insight into the relationship between domain structure and piezoelectric response,which has implications for other piezoelectric ceramics as well.
基金the National Key Research and Development Program(2019YFC0312300)the 111 Project(D21025)+3 种基金National Natural Science Foundation of China Item of China(U20B6005,51874252 and 5177041544)Scientific Research Starting Project of SWPU(2018QHZ007)Open Fund Project of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(PLN2021-02 and PLN2021-03)Found of Southern Marine Science and Engineering Guangdong Laboratory(Zhanjing)(ZJW-2019-03).
文摘There are many emergency risks in the process of natural gas hydrate(NGH)drilling.In order to ensure the safe and efficient exploitation of NGH,it is urgent to establish an intelligent judgment method for the risks in the process of NGH drilling.In this paper,the response relationship between monitoring parameters and risk categories of NGH while drilling is established.Based on fuzzy analytic hierarchy process(FAHP),the comprehensive weights of 10 risk monitoring parameters are obtained,including gas production,wellbore instability,hydrate ice barrier,drill string fracture,sticking,bit balling,drilling tool piercement,gas seepage,seabed subsidence and seabed landslide.Besides,the comprehensive judgment weight matrix is constructed,and the reasonable fluctuation range of monitoring parameters is formed.Thus,the intelligent judgment method of NGH drilling risk is established.The intelligent judgment and alarm of NGH drilling risks can be realized quickly and accurately by this method,namely,it can monitor the risks in the process of operation and guarantee the construction safety of NGH drilling.
基金Basic Science Center Project of NSFC,Grant/Award Number:51788104National Key R&D Program of China,Grant/Award Number:2018YFB0703603。
文摘Isobaric specific heat capacity(Cp)is an important parameter not only in physics but also for most materials.Its accurate measurement is particularly critical for performance evaluation of thermoelectric materials,but the experiments by differential scanning calorimetry(DSC)often lead to large uncertainties in the measurements,especially at elevated temperatures.In this study,we propose a simple method to determine Cp by measuring the sound velocity(υ)based on lattice vibration and expansion theory.The relative standard error of theυis smaller than 1%,showing good accuracy and repeatability.The calculated Cp at elevated temperature(>300 K)increases slightly with increasing temperature due to the lattice expansion,which is more reasonable than the Dulong–Petit value.
基金supported by the National Key R&D Program of China(2018YFB0703603)the State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(KF202111)。
文摘无污染、低成本和高性能Cu_(1.8)S基类液态热电材料受到关注.但是,其过高的本征Cu空位和Cu离子迁移特性限制了其性能和电稳定性的进一步提升.本研究采用机械合金化结合放电等离子体烧结制备了一系列Cu_(1.8)S和Mn_(x)Cu_(1.8)S_(0.5)Se_(0.5)(0.01≤x≤0.06)块体热电材料.随着Se和Mn的引入,体系由低熵Cu_(1.8)S(0.4R^(*))转变为中熵MnxCu_(1.8)S_(0.5)Se_(0.5)(1.2R^(*)).构型熵的增加不仅提高了体系的结构对称性,MnxCu_(1.8)S_(0.5)Se_(0.5)室温下呈立方相结构,还增大了Mn的固溶度.高浓度Mn固溶有效填补了过高的本征Cu空位,降低了载流子浓度,优化了能带结构,提升了电输运性能.熵工程一方面增大了Cu离子迁移势垒,抑制Cu离子迁移.750 K下,即使电流密度达到24 A cm^(-2),Mn_(0.03)Cu_(1.8)S_(0.5)Se_(0.5)的电阻也几乎没有变化,显示出优异的电稳定性;同时可降低声速,软化晶格,降低晶格热导率.Mn_(0.06)Cu_(1.8)S_(0.5)Se_(0.5)的块体样品在773 K时获得最大ZT值0.79,相较于初始样品提高了两倍.结果表明熵工程结合Cu空位工程是提升Cu_(1.8)S基热电材料性能的有效策略.
基金supported by the Basic Science Center Project of the National Natural Science Foundation of China(51788104)the National Key R&D Program of China(2018YFB0703603)。
文摘Fabrication of nanoparticle-dispersed composites is an effective strategy for enhancing the performance of thermoelectric materials,and in particular SiC nanoparticles have been often used to create composites with Bi_(2)Te_(3)-based applied thermoelectric materials.However,the effect of particle size on the thermoelectric performance is unclear.This work systematically investigated the electrical and thermal properties of a series of(Bi,Sb)_(2)Te_(3)-based nanocomposites containing dispersed SiC nanoparticles of different sizes.It was found that particle size has a significant impact on the electrical properties with smaller SiC nanoparticles giving rise to higher electrical conductivity.Even though the dispersed SiC nanoparticles enhanced the Seebeck coefficient,no apparent dependence of the enhancement on the particle size was observed.It was also found that smaller SiC nanoparticles scatter phonons to some extent while the larger nanoparticles contribute to increased thermal conductivity.Eventually,the highest ZT value of 1.12 was obtained in 30 nm-SiC dispersed sample,corresponding to an increase by 18%from 0.95 for the matrix made from commercial scraps,and then the ZT was further boosted to 1.33 by optimizing the matrix composition and expelling excess Te during the optimized spark plasma sintering process.This work proves that the dispersion of smaller SiC nanoparticles in p-type(Bi,Sb)_(2)Te_(3) materials is more effective than the dispersion of larger nanoparticles.In addition,it is revealed that additional compositional and/or processing optimization is vital and effective for obtaining further performance enhancement for nanocomposites of SiC nanoparticles dispersed in(Bi,Sb)_(2)Te_(3).
基金Supported by the National Natural Science Foundation of China （10871161, 11371177）.
文摘In this paper, we establish a Hua-Like theorem in some kind of semirings. This can be regarded as a generalized version of Hua＇s theorem from rings to semirings.
基金supported by the National Key R&D Program of China(No.2018YFB0703603)。
文摘Extremely low lattice thermal conductivity is always the pursuit of thermoelectric materials research.In this work,we reported an exceptional effect of Ag2S addition in MnTe,an emerging promising midtemperature thermoelectric material,to enable the realization of minimum lattice thermal conductivity,namely-0.4 Wm^(-1) K^(-1).Such a low lattice thermal conductivity is guaranteed by the incorporation of in-situ formed Ag rich phase(Ag2Te)with ultralow lattice thermal conductivity and further scattering of phonons from the partial doping effects induced point defects and boundaries between various phases.Apart from the dramatically decreased lattice thermal conductivity,the partial doping of Ag and S simultaneously enhance the electrical conductivity,further contributing to enhanced thermoelectric performance.Meanwhile,an inverse sign of Seebeck and Hall coefficient was observed and rationalized by the influence of highly electron-conductive Ag_(2)Te phase.Thanks to the synergetic modulation of electrical and thermal transport properties by in-situ formed composite,a high ZT value of 1.1 was achieved in MnTe based thermoelectric materials,which also demonstrates the importance of compositing approaches to design state-of-the-art thermoelectric materials.
基金the 111 Project(D21025)National Key Research and Development Program(2019YFC0312300)+2 种基金National Natural Science Foundation Item of China(U20B6005-05,51874252 and 5177041544)Open Fund Project of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(PLN2021-02 and PLN2021-03)the Fund of Southern Marine Science and Engineering Guangdong Laboratory(Zhanjiang)(ZJW-2019-03).
文摘It is easy to change the original temperature state of marine gas hydrate reservoir by drilling,which leads to uncontrollable decomposition of gas hydrate and release of large amount of gas.The decomposition gas will further escape and expand,and the reservoir will break and collapse due to its weak cementation characteristic,which will easily lead to a series of other potential risks.Therefore,in this study,based on the drilling process of marine gas hydrate,we establish the theoretical model and numerical calculation method of wellbore temperature field,analyze the influence on wellbore temperature of drilling fluid displacement,density,viscosity and injection temperature,and seawater depth.Then the sensitivity laws of reservoir risk in marine gas hydrate drilling are obtained.The results show that with the increase of drilling fluid displacement,density,viscosity and injection temperature,the temperature in lower well section and bottom hole will increase,making the increasing amplitude of temperature in hydrate reservoir larger and the scope of influence on hydrate reservoir stability bigger.Moreover,drilling is more likely to raise the temperature of reservoirs in shallow seawater depth,posing greater risks.Thus,engineering measures to avoid risks caused by rising reservoir temperature in marine gas hydrate reservoir drilling are presented.This study is of great significance to ensure the safety of marine gas hydrate reservoir drilling.
