Water alternating gas(WAG)injection is a widely used strategy for enhancing oil recovery(EOR)during gas flooding,and the mechanisms,operating parameters,and influencing factors of which have been extensively studied.H...Water alternating gas(WAG)injection is a widely used strategy for enhancing oil recovery(EOR)during gas flooding,and the mechanisms,operating parameters,and influencing factors of which have been extensively studied.However,with respect to its capacity in expanding macroscopic sweep volume under varying heterogeneities,the related results appear inadequate.In this research,three cores with different heterogeneities were used and flooded by the joint water and CO_(2) WAG,then the effects of heterogeneity on oil recovery were determined.More importantly,the cores after CO_(2) WAG injection were investigated using the nuclear magnetic resonance(NMR)technique for remaining oil distribution research,which could help us to understand the capacity of CO_(2) WAG in enlarging sweep volume at different heterogeneities.The results show that the presence of heterogeneity may largely weaken the effectiveness of water flooding,the more severe the heterogeneity,the worse the water flooding.The WAG injection of CO_(2) performs well in EOR after water flooding for all the cores with different heterogeneities;however,it could barely form a complete or full sweep throughout the low-permeability region,and un-swept bypassed regions remain.The homogeneous core is better developed by the injection of the joint water and CO_(2) WAG than the heterogeneous and fractured cases.展开更多
BACKGROUND Intra-articular glenohumeral joint injections are essential procedures for treating various shoulder disorders. Fluoroscopy-guided injections have been extensively used;however, they pose a risk of radiatio...BACKGROUND Intra-articular glenohumeral joint injections are essential procedures for treating various shoulder disorders. Fluoroscopy-guided injections have been extensively used;however, they pose a risk of radiation exposure and are expensive and timeconsuming. Recently, it has been suggested that ultrasound-guided injections are accurate and cost effective procedures.AIM To evaluate the accuracy of ultrasound-guided glenohumeral injections using a posterior approach that is confirmed using magnetic resonance arthrography(MRA).METHODS The study included 179 shoulders of patients with recurrent anterior instability(150 patients;103 and 76 right and left shoulders, respectively;160 males and 19 females;average age = 20.5 years;age range: 14-63 years) who underwent MRA for preoperative diagnosis. They were injected with 12 m L lidocaine(1%) using the ultrasound-guided posterior approach and then underwent magnetic resonance imaging. Two shoulder surgeons, except for the injector, evaluated the transverse relaxation(T2)-weighted images of axial planes and classified the intraarticular condition of injected contrast into three groups based on one of the three following scenarios: no leakage, injection into the glenohumeral joint without leakage;minor leakage, practical intra-articular injection with some leakage outside the posterior rotator cuffs;and major leakage, inaccurate injection with mass leakage without any contrast into the joint. The inter-rater reliability between two assessors was also evaluated by calculating Cohen’s kappa coefficient. The learning curve was assessed regarding the inaccurate injection rate by analyzing Spearman’s rank correlation coefficient.RESULTS Of the 179 injections, 163 shoulders(91.0%) had no leakage, 10 shoulders(5.6%) had minor leakage, and six shoulders(3.4%) had major leakage. In total, 173 shoulders(96.6%) were intraarticularly injected;thus, we could detect anterior labrum and capsular pathologies. Regarding the inter-rater reliability, the kappa coefficient was 0.925, indicating consistency in the evaluations by both examiners. Regression analysis of the inaccurate injection rate for assessingtechnical learning showed a logarithmic curve with a downward trend(R;= 0.887, P < 0.001). Three(50%) of the six inaccurate injections classified into “major leakage” were observed in the first 30 injections, indicating that the accurate injection showed a leaning effect.CONCLUSION Ultrasound-guided intra-articular glenohumeral injections using a posterior approach had high accuracy;however, injection accuracy depends on clinical experience.展开更多
Tight sandstone gas reservoirs have poorer porosityepermeability relationships,so conventional reservoir classification schemes can hardly satisfy the classification and evaluation demand of this type of reservoirs.To...Tight sandstone gas reservoirs have poorer porosityepermeability relationships,so conventional reservoir classification schemes can hardly satisfy the classification and evaluation demand of this type of reservoirs.To solve this problem,this paper took the Permian tight sandstone gas reservoir in the Linxing Block along the eastern margin of the Ordos Basin as an example to describe the micro-structures of the tight sandstone reservoirs by means of high-pressure mercury injection,nuclear magnetic resonance(NMR),scanning electron mi-croscope(SEM)and so on.Then,the control effect of micro-structure parameters on the macrophysical properties was studied.Finally,classification and evaluation of tight sandstone reservoirs were carried out on this basis.And the following research results were obtained.First,NMR can identify the distribution of pores of different sizes,and high-pressure mercury injection can reflect the poreethroat configuration and percolation capacity of a reservoir.Second,both methods are better coincident in the description results.With an in-crease of the right peak of T2 spectra,the mercury intrusion curve presents a concave shape and the pore throat radius increases while the pore type gradually changes from intragranular dissolution pores and intercrystalline pores to intergranular pores and intergranular disso-lution pores and the reservoir quality gets better.Third,micro-pore structure controls reservoir physical properties andfluid mobility.And the porosity of large pores is best correlated with the effective porosity,so it can be used to evaluate the reservoir capacity of tight sandstone.Fourth,the throat radius R15 obtained by high pressure mercury injection is in the best correlation with porosity and permeability,so it can be used to evaluate the percolation capacity of tight sandstone.Fifth,by combining the porosity of large pores with the R15,the tight sandstone reservoirs in the Linxing Block are classified into 4 categories,and the classification results are in a good agreement with the on-site well test data.It is concluded that the combination of high-pressure mercury injection and NMR can effectively identify the key parameters which reflect the reservoir capacity and percolation capacity of tight sandstone,and improve the reliability and integrity of reservoir classification.And by selecting the key parameters that reflect reservoir capacity and percolation capacity,it can provide guidance for the classification and evaluation of tight sandstone reservoirs.展开更多
Injection rate is crucial for determining the hydraulic fracturing effectiveness;however,the effects of the injection rate on the pore and fracture structure(PFS)and fluid infiltration during injection pressurization ...Injection rate is crucial for determining the hydraulic fracturing effectiveness;however,the effects of the injection rate on the pore and fracture structure(PFS)and fluid infiltration during injection pressurization have rarely been explored.In this study,the cylindrical sandstone samples were hydraulically fractured at various injection rates on a self-developed integrated nuclear magnetic resonance(NMR)and hydraulic fracturing experimental system.The results show that low injection rates predominantly resulted in macropore-scale damage by creating intergranular cracks,whereas high injection rates facilitated micropore-scale damage,probably owing to the adsorption swelling effect of clay minerals within pores.Additionally,the water contents of the samples with low injection rates exhibited a continuous increase,whereas those of the samples with high injection rates initially increased and subsequently stabilized.Magnetic resonance imaging(MRI)indicated that fluid infiltration during the fracturing process exhibited high anisotropy owing to the inherent heterogeneous PFS distributions around the wellbore.Moreover,a primary fluid infiltration path exists that aligns with the initiation direction of the hydraulic fractures.However,the fluid infiltration damage distance along the hydraulic fracture direction decreased with increasing injection rate,whereas the fluid infiltration damage distance perpendicular to the hydraulic fracture direction was approximately equal to the characteristic length,regardless of the injection rate.Finally,we recommend using the pore damage during fluid pressurization as the basis for selecting the proppant size and employing a primary fluid infiltration path to predict hydraulic fracture initiation.These findings provide valuable insights into the design of hydraulic fracturing in tight gas reservoirs.展开更多
The spin transport property of a ferromagnet （FM）/insulator （Ⅰ）/resonant tunneling diode （RTD） heterostructure was studied. The transmission coefficient and spin polarization in a multilayered heterostructure w...The spin transport property of a ferromagnet （FM）/insulator （Ⅰ）/resonant tunneling diode （RTD） heterostructure was studied. The transmission coefficient and spin polarization in a multilayered heterostructure was calculated by a Schrdinger wave equation. An Airy function formalism approach was used to solve this equation. Based on the transfer matrix approach,the transmittivity of the structure was determined as a function of the Feimi energy and other parameters. The result shows that the spin polarization induced by the structure oscillates with the increasing Fermi energy of the FM layer. While the thickness of the RTD is reduced,the resonant peaks become broad. In the heterostructure,the spin polarization reaches as high as 40% and can be easily controlled by the external bias voltage.展开更多
Objective To observe the effect of Danhong injection(DI)in patients with acute ST-segment elevation myocardial infarction(STEMI)at a high risk of no-reflow(NR)during primary percutaneous coronary intervention(PCI).Met...Objective To observe the effect of Danhong injection(DI)in patients with acute ST-segment elevation myocardial infarction(STEMI)at a high risk of no-reflow(NR)during primary percutaneous coronary intervention(PCI).Methods Patients were placed in a DI group and control group.The DI group was given DI and the control group was given physiologic saline.The administration lasted 4 to 6 days in both groups after PCI.Cardiac magnetic resonance(CMR)was carried out during the perioperative period(7±2 days).The primary endpoint of the study was myocardial infarct size(IS)imaged on delayed-enhancement CMR.The secondary endpoint was major adverse cardiac events observed 6 months after PCI.Results In total,160 high-risk NR patients were enrolled,and 110 patients completed the CMR examination.According to postoperative CMR,the Myocardial Salvage Index and left ventricular ejection fraction were higher in the DI group(0.57±0.13 vs.0.48±0.17,P<0.01;49.3%±6.9%vs.46.2%±7.7%,P=0.03,respectively),whereas the IS was lower(19.7%±5.6%vs.22.2%±6.5%,P=0.04),compared with that in the control group.These differences were observed to be significant.After 6 months,the prevalence of major adverse cardiac events in the DI group decreased compared with that in the control group,but the differences were not observed to be significant(P>0.05).Conclusion The application of DI can reduce the myocardial infarct size in STEMI patients at a high risk of NR during primary PCI.展开更多
Postaurical injection of therapeutics was recently applied in clinical practice to treat inner ear diseases based on supposed existence of a direct channel from the postaurical area to the inner ear. Doubting on the a...Postaurical injection of therapeutics was recently applied in clinical practice to treat inner ear diseases based on supposed existence of a direct channel from the postaurical area to the inner ear. Doubting on the associated reports and aiming to provide evidence on the inner ear uptake mechanism, the present study tracked the dynamic distribution of gadolinium-tetra-azacyclo-dodecane-tetra-acetic acid (Gd-DOTA) in rat inner ears after postaurical injection using MRI. A targeted tympanic medial wall delivery was utilized as control. The results showed that, at the early time points after postaurical injection, Gd-DOTA distributed mainly in tissues surrounding the bulla, temporal bone and skull and neck space. In the inner ear, there was gradual uptake of Gd-DOTA on both the ipsilateral and contralateral sides with equal signal intensities. There was no sign of direct channel carrying the agent from the postaurical area to the inner ear. Targeted tympanic medial wall delivery induced significantly greater uptake of Gd-DOTA in the inner ear than did postaurical injection. At 30 min post-administration, targeted tympanic medial wall delivery yielded 4.6-folds higher signal intensity than did postaurical injection. The total dose of Gd-DOTA delivered by the targeted tympanic medial wall approach was only 0.1% of that delivered by postaurical injection. In conclusion, postaurical injection is a systemic administration, which is similar to hypodermic injection, rather than a focal delivery method. By contraries, targeted tympanic medial wall delivery induces fast and abundant uptake of Gd-DOTA in the ipsilateral inner ear without significant distribution in unwanted areas.展开更多
AIM: To investigate if the clinical outcome of intraarticular lumbar facet joint injections is affected by the therapist's attitude. METHODS: A total of 40 patients with facet jointassociated chronic low back pain...AIM: To investigate if the clinical outcome of intraarticular lumbar facet joint injections is affected by the therapist's attitude. METHODS: A total of 40 patients with facet jointassociated chronic low back pain were randomly divided into two groups. All patients received computed tomography-guided, monosegmental intra-articular facet joint injections. Following the therapeutic procedure, the patients of the experimental group(EG) held a conversation with the radiologist in a comfortable atmosphere. During the dialog, the patients were encouraged to ask questions and were shown four images. The patients of the control group(CG) left the clinic without any further contact with the radiologist. Outcome was assessed using a pain-based Verbal Numeric Scale at baseline, at 1 wk and at 1, 3, and 6 mo after first treatment. RESULTS: The patient demographics showed no differences between the groups. The patients of the EG received 57 interventional procedures in total, while the patients of the CG received 70 interventional procedures. In both groups, the pain scores decreased significantly over the entire observation period. Compared to the CG, the EG showed a statistically significant reduction of pain at 1 wk and 1 mo post-treatment, while at 3 and 6 mo after treatment, there were no significant differences between both groups. CONCLUSION: Our results show a significant effect on pain relief during the early post-interventional period in the EG as compared to the CG. The basic principle behind the higher efficacy might be the phenomenon of hetero-suggestion.展开更多
An injection-seeded single-frequency Q-switched Nd：YAG laser is accomplished by using a phase modulated rampfire technique. A RbTiOPO4（RTP） electro-optic crystal is selected for effective optical path length modula...An injection-seeded single-frequency Q-switched Nd：YAG laser is accomplished by using a phase modulated rampfire technique. A RbTiOPO4（RTP） electro-optic crystal is selected for effective optical path length modulation of the slave self-filtering unstable resonator. This single-frequency laser is capable of producing 50 m J pulse energy at 1 Hz repetition rate with a pulse width of 16 ns. The standard deviation of laser pulse intensity for consecutive 100 shots from the mean pulse intensity is less than 1.05%. A spectral linewidth of less than 0.5 pm with a frequency jitter of about 14 fm over30 min is obtained.展开更多
To perform the mechanism study of special association for vancomycin and D-Ala-D-Ala-containing peptides on the interface of solution and self-assemble monolayer, the binding between vancomycin and pentapeptide （Lys-...To perform the mechanism study of special association for vancomycin and D-Ala-D-Ala-containing peptides on the interface of solution and self-assemble monolayer, the binding between vancomycin and pentapeptide （Lys-Lys-Gly-D-Ala-D-Ala） was investigated by flow injection surface plasmon resonance （FI-SPR） and flow injection quartz crystal microbalance （FI-QCM）. To facilitate the formation of a compact vancomycin adsorbates layer with a uniform surface orientation, vancomycin molecules were attached onto a preformed alkanethiol self-assembled monolayer. By optimizing the conditions for the binding between Lys-Lys-Gly-D-Ala-D-Ala and vancomycin on the assembled chip, the detecting limit of Lys-Lys-Gly-D-Ala-D-Ala was greatly improved （reaching 0.5 ×10^- 6 mol/L or 7.5 × 10^-12 mol）. The equilibrium constant of the association of Lys-Lys-Gly-D-Ala-D-Ala with vancomycin was also obtained （KAds=5.0×10^4 L/tool）.展开更多
Aiming at training the feed-forward threshold neural network consisting of nondifferentiable activation functions, the approach of noise injection forms a stochastic resonance based threshold network that can be optim...Aiming at training the feed-forward threshold neural network consisting of nondifferentiable activation functions, the approach of noise injection forms a stochastic resonance based threshold network that can be optimized by various gradientbased optimizers. The introduction of injected noise extends the noise level into the parameter space of the designed threshold network, but leads to a highly non-convex optimization landscape of the loss function. Thus, the hyperparameter on-line learning procedure with respective to network weights and noise levels becomes of challenge. It is shown that the Adam optimizer, as an adaptive variant of stochastic gradient descent, manifests its superior learning ability in training the stochastic resonance based threshold network effectively. Experimental results demonstrate the significant improvement of performance of the designed threshold network trained by the Adam optimizer for function approximation and image classification.展开更多
Posterior disc displacement of the temporomandibular joint is rare. We present a unique treatment method and magnetic resonance (MR) images of this condition. The patient was a 43-year-old male with a chief complaint ...Posterior disc displacement of the temporomandibular joint is rare. We present a unique treatment method and magnetic resonance (MR) images of this condition. The patient was a 43-year-old male with a chief complaint of abnormal occlusion. Regarding the present status, there was no occlusion on the right side. No temporomandibular joint pain, myalgia, or clicking were observed while mouth opening. On MR images, the posterior disc displacement without reduction on the right was observed and it was assumed that occlusal abnormality was due to this condition. We treated him with the following methods. After injection into the superior articular cavity with 2% lidocaine, a sodium hyaluronate preparation was injected followed by intermaxillary traction applied using rubber. The recovery of occlusion was confirmed in follow-up at 5 days after treatment. In the 13th days, the intermaxillary traction was removed. On MR images, the right disc condition was changed to anterior disc displacement with reduction. We consider our treatment methods are effective for this clinical condition.展开更多
The injection and extraction system of Charge Stripping Injection(CSI) and 1 Charge Stripping Injection of HIRFL-CSR progressed steadily in slow extraction of CSRm, design and 2001. The progress covers design developm...The injection and extraction system of Charge Stripping Injection(CSI) and 1 Charge Stripping Injection of HIRFL-CSR progressed steadily in slow extraction of CSRm, design and 2001. The progress covers design development of components.For beam accumulation schemes of CSRm, besides of Multiple Multi-turn Injection(MMI) and RF Stacking(RFS), Charge Stripping Injection(CSI) is designed for accumulation of light ions(C～Ne). It’s well展开更多
With a live wire, line impedance could be measured by means of only passive elements such as inductors or resistors, whose techniques are well known. However, as the voltage and current used for the measurement are in...With a live wire, line impedance could be measured by means of only passive elements such as inductors or resistors, whose techniques are well known. However, as the voltage and current used for the measurement are increased, the size of the inductor or resistor being used also needs to be increased, so it would be virtually impossible to make an accurate measurement. Because of this, the authors have developed a novel measurement method for line impedance using LC resonance, which the authors describe first place. In the second place, the authors propose another line impedance. The novel method is that the rectangular wave with minimum voltage is injected into the distribution line system. By means of this method, the line capacitance and the line inductance can be measured. These proposals are confirmed by the simulation or experiment. Finally, the frequency response analysis method is to be examined, whose mechanism and results are to be presented and discussed.展开更多
The distinction between two microwave equivalent-circuit models,quasi Esaki tunneling model (QETM) and quantum well injection transit model (QWITM),for the resonant tunneling diode (RTD) is discussed in details,and tw...The distinction between two microwave equivalent-circuit models,quasi Esaki tunneling model (QETM) and quantum well injection transit model (QWITM),for the resonant tunneling diode (RTD) is discussed in details,and two groups of circuit parameters are extracted from experiment data by the least square fit method.Both theory analysis and the comparison of fit results demonstrate that QWITM is much more precise than QETM.In addition,the rationality of QWITM circuit's parameters confirms it too.On this basis,the resistive frequency is calculated,whose influence factors and improvement method are simply discussed as well.展开更多
In a hollow-core fiber(HCF),light propagates through an air/vacuum core rather than a solid material,resulting in a low thermo-optic coefficient and ability to handle high powers.Here,we demonstrate a laser locked to ...In a hollow-core fiber(HCF),light propagates through an air/vacuum core rather than a solid material,resulting in a low thermo-optic coefficient and ability to handle high powers.Here,we demonstrate a laser locked to a hollow-core fiber reference,which thanks to the low HCF thermal sensitivity,shows long-term stability an order of magnitude better than compact commercially available low-noise lasers.The laser frequency variation within±600 kHz was measured over 50 h.The stability of our proof-of-concept laser is ensured via a strong selfinjection ratio of-15 dB,enabled by the high-power handling and low loss of the hollow-core fiber's resonator.Moreover,our results show appealing performance parameters,including a fractional frequency stability of4×10^(-13)at 1 s averaging time and a Lorentzian component of the linewidth of 0.2 Hz.展开更多
In pH 4.2-5.2 HOAc-NaOAc buffer solution, Ag＋ reacted with dihalogenated fluorescein （DHF） dyes to form a 1 ; 2 anionic complex. This anionic complex could further react with hyoscine butylbromide （HBB） to form 1...In pH 4.2-5.2 HOAc-NaOAc buffer solution, Ag＋ reacted with dihalogenated fluorescein （DHF） dyes to form a 1 ; 2 anionic complex. This anionic complex could further react with hyoscine butylbromide （HBB） to form 1 ： 1 ion-association complex, which resulted in the significant enhancement of resonance Rayleigh scattering （RRS） intensity. Therefore, a novel method for the determination of HBB by resonance Rayleigh scattering （RRS） coupled with flow injection analysis （FIA） technique has been established. The present method had been applied to determine HBB in capsules and the results were in good agreement with those obtained by the literature method.展开更多
基金Project(KFJJ-TZ-2019-3)supported by the Open Project of Shaanxi Key Laboratory of Advanced Stimulation Technology for Oil&Gas Reservoirs,ChinaProjects(51504275,51974344)supported by the National Natural Science Foundation of China。
文摘Water alternating gas(WAG)injection is a widely used strategy for enhancing oil recovery(EOR)during gas flooding,and the mechanisms,operating parameters,and influencing factors of which have been extensively studied.However,with respect to its capacity in expanding macroscopic sweep volume under varying heterogeneities,the related results appear inadequate.In this research,three cores with different heterogeneities were used and flooded by the joint water and CO_(2) WAG,then the effects of heterogeneity on oil recovery were determined.More importantly,the cores after CO_(2) WAG injection were investigated using the nuclear magnetic resonance(NMR)technique for remaining oil distribution research,which could help us to understand the capacity of CO_(2) WAG in enlarging sweep volume at different heterogeneities.The results show that the presence of heterogeneity may largely weaken the effectiveness of water flooding,the more severe the heterogeneity,the worse the water flooding.The WAG injection of CO_(2) performs well in EOR after water flooding for all the cores with different heterogeneities;however,it could barely form a complete or full sweep throughout the low-permeability region,and un-swept bypassed regions remain.The homogeneous core is better developed by the injection of the joint water and CO_(2) WAG than the heterogeneous and fractured cases.
文摘BACKGROUND Intra-articular glenohumeral joint injections are essential procedures for treating various shoulder disorders. Fluoroscopy-guided injections have been extensively used;however, they pose a risk of radiation exposure and are expensive and timeconsuming. Recently, it has been suggested that ultrasound-guided injections are accurate and cost effective procedures.AIM To evaluate the accuracy of ultrasound-guided glenohumeral injections using a posterior approach that is confirmed using magnetic resonance arthrography(MRA).METHODS The study included 179 shoulders of patients with recurrent anterior instability(150 patients;103 and 76 right and left shoulders, respectively;160 males and 19 females;average age = 20.5 years;age range: 14-63 years) who underwent MRA for preoperative diagnosis. They were injected with 12 m L lidocaine(1%) using the ultrasound-guided posterior approach and then underwent magnetic resonance imaging. Two shoulder surgeons, except for the injector, evaluated the transverse relaxation(T2)-weighted images of axial planes and classified the intraarticular condition of injected contrast into three groups based on one of the three following scenarios: no leakage, injection into the glenohumeral joint without leakage;minor leakage, practical intra-articular injection with some leakage outside the posterior rotator cuffs;and major leakage, inaccurate injection with mass leakage without any contrast into the joint. The inter-rater reliability between two assessors was also evaluated by calculating Cohen’s kappa coefficient. The learning curve was assessed regarding the inaccurate injection rate by analyzing Spearman’s rank correlation coefficient.RESULTS Of the 179 injections, 163 shoulders(91.0%) had no leakage, 10 shoulders(5.6%) had minor leakage, and six shoulders(3.4%) had major leakage. In total, 173 shoulders(96.6%) were intraarticularly injected;thus, we could detect anterior labrum and capsular pathologies. Regarding the inter-rater reliability, the kappa coefficient was 0.925, indicating consistency in the evaluations by both examiners. Regression analysis of the inaccurate injection rate for assessingtechnical learning showed a logarithmic curve with a downward trend(R;= 0.887, P < 0.001). Three(50%) of the six inaccurate injections classified into “major leakage” were observed in the first 30 injections, indicating that the accurate injection showed a leaning effect.CONCLUSION Ultrasound-guided intra-articular glenohumeral injections using a posterior approach had high accuracy;however, injection accuracy depends on clinical experience.
基金supported by the National Natural Science Foundation of China"Full-borchole pore throat characterization and modeling of tight sandstone based on the combination of image method and fluid method"(No.41602141)"Mechanism and effects of imbibition and retention of fracturing fluid in in-situ shale gas reservoirs"(No.41972139)the Independent Innovation Foundation of Universities(No.18CX02069A).
文摘Tight sandstone gas reservoirs have poorer porosityepermeability relationships,so conventional reservoir classification schemes can hardly satisfy the classification and evaluation demand of this type of reservoirs.To solve this problem,this paper took the Permian tight sandstone gas reservoir in the Linxing Block along the eastern margin of the Ordos Basin as an example to describe the micro-structures of the tight sandstone reservoirs by means of high-pressure mercury injection,nuclear magnetic resonance(NMR),scanning electron mi-croscope(SEM)and so on.Then,the control effect of micro-structure parameters on the macrophysical properties was studied.Finally,classification and evaluation of tight sandstone reservoirs were carried out on this basis.And the following research results were obtained.First,NMR can identify the distribution of pores of different sizes,and high-pressure mercury injection can reflect the poreethroat configuration and percolation capacity of a reservoir.Second,both methods are better coincident in the description results.With an in-crease of the right peak of T2 spectra,the mercury intrusion curve presents a concave shape and the pore throat radius increases while the pore type gradually changes from intragranular dissolution pores and intercrystalline pores to intergranular pores and intergranular disso-lution pores and the reservoir quality gets better.Third,micro-pore structure controls reservoir physical properties andfluid mobility.And the porosity of large pores is best correlated with the effective porosity,so it can be used to evaluate the reservoir capacity of tight sandstone.Fourth,the throat radius R15 obtained by high pressure mercury injection is in the best correlation with porosity and permeability,so it can be used to evaluate the percolation capacity of tight sandstone.Fifth,by combining the porosity of large pores with the R15,the tight sandstone reservoirs in the Linxing Block are classified into 4 categories,and the classification results are in a good agreement with the on-site well test data.It is concluded that the combination of high-pressure mercury injection and NMR can effectively identify the key parameters which reflect the reservoir capacity and percolation capacity of tight sandstone,and improve the reliability and integrity of reservoir classification.And by selecting the key parameters that reflect reservoir capacity and percolation capacity,it can provide guidance for the classification and evaluation of tight sandstone reservoirs.
基金supported by the National Natural Science Foundation of China(Grant.Nos.52364004,52464005)the Youth Talent Growth Project of Guizhou Provincial Department of Education(Grant No.QianJiaoJi[2024]18).
文摘Injection rate is crucial for determining the hydraulic fracturing effectiveness;however,the effects of the injection rate on the pore and fracture structure(PFS)and fluid infiltration during injection pressurization have rarely been explored.In this study,the cylindrical sandstone samples were hydraulically fractured at various injection rates on a self-developed integrated nuclear magnetic resonance(NMR)and hydraulic fracturing experimental system.The results show that low injection rates predominantly resulted in macropore-scale damage by creating intergranular cracks,whereas high injection rates facilitated micropore-scale damage,probably owing to the adsorption swelling effect of clay minerals within pores.Additionally,the water contents of the samples with low injection rates exhibited a continuous increase,whereas those of the samples with high injection rates initially increased and subsequently stabilized.Magnetic resonance imaging(MRI)indicated that fluid infiltration during the fracturing process exhibited high anisotropy owing to the inherent heterogeneous PFS distributions around the wellbore.Moreover,a primary fluid infiltration path exists that aligns with the initiation direction of the hydraulic fractures.However,the fluid infiltration damage distance along the hydraulic fracture direction decreased with increasing injection rate,whereas the fluid infiltration damage distance perpendicular to the hydraulic fracture direction was approximately equal to the characteristic length,regardless of the injection rate.Finally,we recommend using the pore damage during fluid pressurization as the basis for selecting the proppant size and employing a primary fluid infiltration path to predict hydraulic fracture initiation.These findings provide valuable insights into the design of hydraulic fracturing in tight gas reservoirs.
基金the National Natural Science Foundation of China and Beijing (No50831002,No50701005)the Specialized Research Fund for the Doctoral Program of Higher Education of China (No20070008024)+1 种基金the National Basic Research and Development Program of China (No2007CB936202)the Foundation of the Ministry of Education of China for Returned Scholars
文摘The spin transport property of a ferromagnet （FM）/insulator （Ⅰ）/resonant tunneling diode （RTD） heterostructure was studied. The transmission coefficient and spin polarization in a multilayered heterostructure was calculated by a Schrdinger wave equation. An Airy function formalism approach was used to solve this equation. Based on the transfer matrix approach,the transmittivity of the structure was determined as a function of the Feimi energy and other parameters. The result shows that the spin polarization induced by the structure oscillates with the increasing Fermi energy of the FM layer. While the thickness of the RTD is reduced,the resonant peaks become broad. In the heterostructure,the spin polarization reaches as high as 40% and can be easily controlled by the external bias voltage.
基金supported by grant from the Capital health research and development of special project (2016-15011)
文摘Objective To observe the effect of Danhong injection(DI)in patients with acute ST-segment elevation myocardial infarction(STEMI)at a high risk of no-reflow(NR)during primary percutaneous coronary intervention(PCI).Methods Patients were placed in a DI group and control group.The DI group was given DI and the control group was given physiologic saline.The administration lasted 4 to 6 days in both groups after PCI.Cardiac magnetic resonance(CMR)was carried out during the perioperative period(7±2 days).The primary endpoint of the study was myocardial infarct size(IS)imaged on delayed-enhancement CMR.The secondary endpoint was major adverse cardiac events observed 6 months after PCI.Results In total,160 high-risk NR patients were enrolled,and 110 patients completed the CMR examination.According to postoperative CMR,the Myocardial Salvage Index and left ventricular ejection fraction were higher in the DI group(0.57±0.13 vs.0.48±0.17,P<0.01;49.3%±6.9%vs.46.2%±7.7%,P=0.03,respectively),whereas the IS was lower(19.7%±5.6%vs.22.2%±6.5%,P=0.04),compared with that in the control group.These differences were observed to be significant.After 6 months,the prevalence of major adverse cardiac events in the DI group decreased compared with that in the control group,but the differences were not observed to be significant(P>0.05).Conclusion The application of DI can reduce the myocardial infarct size in STEMI patients at a high risk of NR during primary PCI.
基金supported by the 1255 project of Changhai HospitalSecond Military Medical University,Shanghai,China
文摘Postaurical injection of therapeutics was recently applied in clinical practice to treat inner ear diseases based on supposed existence of a direct channel from the postaurical area to the inner ear. Doubting on the associated reports and aiming to provide evidence on the inner ear uptake mechanism, the present study tracked the dynamic distribution of gadolinium-tetra-azacyclo-dodecane-tetra-acetic acid (Gd-DOTA) in rat inner ears after postaurical injection using MRI. A targeted tympanic medial wall delivery was utilized as control. The results showed that, at the early time points after postaurical injection, Gd-DOTA distributed mainly in tissues surrounding the bulla, temporal bone and skull and neck space. In the inner ear, there was gradual uptake of Gd-DOTA on both the ipsilateral and contralateral sides with equal signal intensities. There was no sign of direct channel carrying the agent from the postaurical area to the inner ear. Targeted tympanic medial wall delivery induced significantly greater uptake of Gd-DOTA in the inner ear than did postaurical injection. At 30 min post-administration, targeted tympanic medial wall delivery yielded 4.6-folds higher signal intensity than did postaurical injection. The total dose of Gd-DOTA delivered by the targeted tympanic medial wall approach was only 0.1% of that delivered by postaurical injection. In conclusion, postaurical injection is a systemic administration, which is similar to hypodermic injection, rather than a focal delivery method. By contraries, targeted tympanic medial wall delivery induces fast and abundant uptake of Gd-DOTA in the ipsilateral inner ear without significant distribution in unwanted areas.
文摘AIM: To investigate if the clinical outcome of intraarticular lumbar facet joint injections is affected by the therapist's attitude. METHODS: A total of 40 patients with facet jointassociated chronic low back pain were randomly divided into two groups. All patients received computed tomography-guided, monosegmental intra-articular facet joint injections. Following the therapeutic procedure, the patients of the experimental group(EG) held a conversation with the radiologist in a comfortable atmosphere. During the dialog, the patients were encouraged to ask questions and were shown four images. The patients of the control group(CG) left the clinic without any further contact with the radiologist. Outcome was assessed using a pain-based Verbal Numeric Scale at baseline, at 1 wk and at 1, 3, and 6 mo after first treatment. RESULTS: The patient demographics showed no differences between the groups. The patients of the EG received 57 interventional procedures in total, while the patients of the CG received 70 interventional procedures. In both groups, the pain scores decreased significantly over the entire observation period. Compared to the CG, the EG showed a statistically significant reduction of pain at 1 wk and 1 mo post-treatment, while at 3 and 6 mo after treatment, there were no significant differences between both groups. CONCLUSION: Our results show a significant effect on pain relief during the early post-interventional period in the EG as compared to the CG. The basic principle behind the higher efficacy might be the phenomenon of hetero-suggestion.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2017YFB1104500 and 2016YFB0701000)
文摘An injection-seeded single-frequency Q-switched Nd：YAG laser is accomplished by using a phase modulated rampfire technique. A RbTiOPO4（RTP） electro-optic crystal is selected for effective optical path length modulation of the slave self-filtering unstable resonator. This single-frequency laser is capable of producing 50 m J pulse energy at 1 Hz repetition rate with a pulse width of 16 ns. The standard deviation of laser pulse intensity for consecutive 100 shots from the mean pulse intensity is less than 1.05%. A spectral linewidth of less than 0.5 pm with a frequency jitter of about 14 fm over30 min is obtained.
基金Projects(20773165,20876179) supported by the National Natural Science Foundation of ChinaProject(09JJ1002) supported by the Hunan Provincial Natural Science Foundation,China+1 种基金Project(NCET-07-0865) for New Century Excellent Talents in Chinese UniversityProject(2007AA022006) supported by the National High Technology Research and Development Program of China
文摘To perform the mechanism study of special association for vancomycin and D-Ala-D-Ala-containing peptides on the interface of solution and self-assemble monolayer, the binding between vancomycin and pentapeptide （Lys-Lys-Gly-D-Ala-D-Ala） was investigated by flow injection surface plasmon resonance （FI-SPR） and flow injection quartz crystal microbalance （FI-QCM）. To facilitate the formation of a compact vancomycin adsorbates layer with a uniform surface orientation, vancomycin molecules were attached onto a preformed alkanethiol self-assembled monolayer. By optimizing the conditions for the binding between Lys-Lys-Gly-D-Ala-D-Ala and vancomycin on the assembled chip, the detecting limit of Lys-Lys-Gly-D-Ala-D-Ala was greatly improved （reaching 0.5 ×10^- 6 mol/L or 7.5 × 10^-12 mol）. The equilibrium constant of the association of Lys-Lys-Gly-D-Ala-D-Ala with vancomycin was also obtained （KAds=5.0×10^4 L/tool）.
基金Project supported by the Natural Science Foundation of Shandong Province,China(Grant No.ZR2021MF051)。
文摘Aiming at training the feed-forward threshold neural network consisting of nondifferentiable activation functions, the approach of noise injection forms a stochastic resonance based threshold network that can be optimized by various gradientbased optimizers. The introduction of injected noise extends the noise level into the parameter space of the designed threshold network, but leads to a highly non-convex optimization landscape of the loss function. Thus, the hyperparameter on-line learning procedure with respective to network weights and noise levels becomes of challenge. It is shown that the Adam optimizer, as an adaptive variant of stochastic gradient descent, manifests its superior learning ability in training the stochastic resonance based threshold network effectively. Experimental results demonstrate the significant improvement of performance of the designed threshold network trained by the Adam optimizer for function approximation and image classification.
文摘Posterior disc displacement of the temporomandibular joint is rare. We present a unique treatment method and magnetic resonance (MR) images of this condition. The patient was a 43-year-old male with a chief complaint of abnormal occlusion. Regarding the present status, there was no occlusion on the right side. No temporomandibular joint pain, myalgia, or clicking were observed while mouth opening. On MR images, the posterior disc displacement without reduction on the right was observed and it was assumed that occlusal abnormality was due to this condition. We treated him with the following methods. After injection into the superior articular cavity with 2% lidocaine, a sodium hyaluronate preparation was injected followed by intermaxillary traction applied using rubber. The recovery of occlusion was confirmed in follow-up at 5 days after treatment. In the 13th days, the intermaxillary traction was removed. On MR images, the right disc condition was changed to anterior disc displacement with reduction. We consider our treatment methods are effective for this clinical condition.
文摘The injection and extraction system of Charge Stripping Injection(CSI) and 1 Charge Stripping Injection of HIRFL-CSR progressed steadily in slow extraction of CSRm, design and 2001. The progress covers design development of components.For beam accumulation schemes of CSRm, besides of Multiple Multi-turn Injection(MMI) and RF Stacking(RFS), Charge Stripping Injection(CSI) is designed for accumulation of light ions(C～Ne). It’s well
文摘With a live wire, line impedance could be measured by means of only passive elements such as inductors or resistors, whose techniques are well known. However, as the voltage and current used for the measurement are increased, the size of the inductor or resistor being used also needs to be increased, so it would be virtually impossible to make an accurate measurement. Because of this, the authors have developed a novel measurement method for line impedance using LC resonance, which the authors describe first place. In the second place, the authors propose another line impedance. The novel method is that the rectangular wave with minimum voltage is injected into the distribution line system. By means of this method, the line capacitance and the line inductance can be measured. These proposals are confirmed by the simulation or experiment. Finally, the frequency response analysis method is to be examined, whose mechanism and results are to be presented and discussed.
文摘The distinction between two microwave equivalent-circuit models,quasi Esaki tunneling model (QETM) and quantum well injection transit model (QWITM),for the resonant tunneling diode (RTD) is discussed in details,and two groups of circuit parameters are extracted from experiment data by the least square fit method.Both theory analysis and the comparison of fit results demonstrate that QWITM is much more precise than QETM.In addition,the rationality of QWITM circuit's parameters confirms it too.On this basis,the resistive frequency is calculated,whose influence factors and improvement method are simply discussed as well.
基金Engineering and Physical Sciences Research Council(EP/P030181/1)VACUUM(EP/W037440/1)Technology Agency of the Czech Republic(FW03010171)。
文摘In a hollow-core fiber(HCF),light propagates through an air/vacuum core rather than a solid material,resulting in a low thermo-optic coefficient and ability to handle high powers.Here,we demonstrate a laser locked to a hollow-core fiber reference,which thanks to the low HCF thermal sensitivity,shows long-term stability an order of magnitude better than compact commercially available low-noise lasers.The laser frequency variation within±600 kHz was measured over 50 h.The stability of our proof-of-concept laser is ensured via a strong selfinjection ratio of-15 dB,enabled by the high-power handling and low loss of the hollow-core fiber's resonator.Moreover,our results show appealing performance parameters,including a fractional frequency stability of4×10^(-13)at 1 s averaging time and a Lorentzian component of the linewidth of 0.2 Hz.
基金Project supported by the National Natural Science Foundation of China （No. 20875078） and Chongqing Municipal Key Laboratory on Luminescence and Real-Time Analysis （No. CSTC 2006CA8006）.
文摘In pH 4.2-5.2 HOAc-NaOAc buffer solution, Ag＋ reacted with dihalogenated fluorescein （DHF） dyes to form a 1 ; 2 anionic complex. This anionic complex could further react with hyoscine butylbromide （HBB） to form 1 ： 1 ion-association complex, which resulted in the significant enhancement of resonance Rayleigh scattering （RRS） intensity. Therefore, a novel method for the determination of HBB by resonance Rayleigh scattering （RRS） coupled with flow injection analysis （FIA） technique has been established. The present method had been applied to determine HBB in capsules and the results were in good agreement with those obtained by the literature method.
