•The coupling relations among thermal and mechanical properties of Double-V cellular structure (DVCS) are established.•DVCS can be regarded as a medium to set up the relations among thermal and ...mechanical properties of battery module.•DVCS with variable density gradient distribution are embedded between battery cells and can resolve the issues of temperature non-uniformity and poor collision performance of battery module.
To further enhance the thermal–mechanical performances of battery module, a novel lithium-ion battery module with double-V cellular structure (DVCS) is proposed. Firstly, the temperature field distributions of battery module are acquired by employing ANSYS/ Fluent simulation analysis software. Subsequently, mechanical properties of the DVCS are acquired and quasi-static compression test is also executed to verify the accuracy of theoretical predictions and emulation analysis. Then, the thermo-mechanical coupling models of DVCS are established, and the optimal geometric parameters of DVCS can be obtained through multi-objective thermal–mechanical coupling optimization method. Based on the above, density gradient of the DVCS can be defined based on the temperature field distribution of battery module. Eventually, in comparisons to battery module with single cooling tube and battery module with the optimal DVCS, the maximum temperature of battery module with density gradient DVCS is 304.97 K at 3C discharge rate, which decreases by 4.51 % and 3.16 %, respectively, the maximum temperature difference of battery module with density gradient DVCS is 4.97 K, which decreases by 74.36 % and 66.71 %, accordingly. As for extrusion conditions, the maximum intrusion displacements of battery module with density gradient DVCS are 0.2295 mm and 0.6518 mm along X and Y directions, separately, which decrease by 94.54 % and 86.87 % compared with those of battery module with single cooling tube. The results indicate that the dissipation efficiency, temperature uniformity and collision performances of battery module with density gradient DVCS can be improved greatly.
The characteristics of non-connected pores of four Longmaxi shale samples from the southern Sichuan Basin of China were investigated from the studies of pore size distribution (PSD), pore volumes, ...pore types using helium pycnometry gas injection porosimetry (GIP) and GRI (Gas Research Institute) method, nuclear magnetic resonance (NMR), nuclear magnetic resonance cryoporometry (NMRc), and spontaneous water and oil imbibition experiments. GRI porosity on particle sizes less than 5 mm sample and a 2 MPa helium injection pressure provides information on the total porosity, including both non-connected and connected pores. GIP porosity using core plugs only measures connected pores which extend to the surface of the sample accessible by helium. So the difference between GRI and GIP porosities is used to estimate the volumes of non-connected pores. And the volumes of non-connected pores accounts for 17.5%–40.3% of the total pore volume. For NMRc test results, total pore volume increases with sample size decrease, and the great difference of pore volume with a pore diameter range from 5 nm to 31 nm between small cylinder sample and 0.15–0.075 mm crushed sample is caused by non-connected pores opened. With a decrease of length for cubic samples, the increase in volume and rate of oil imbibition is greater than that of water imbibition, indicating that the non-connected pores are considered to be mainly oil-wet. In addition, the percentage of non-connected pores has a good correlation with TOC (total organic carbon) content. Therefore, this evidence implies that non-connected pores are mainly within the organic matter. NMR tests at different drying temperatures and a NMRc experiment provide a quantitative classification of the shale pore system which indicates that the exploitable pore diameters are larger than 4.25 nm. So non-connected pores with a diameter of 5–31 nm could be effectively exploited if connected by fracturing. The more the non-connected pores are opened, the better the pore connectivity of shale reservoir will be, with a less possibility of water blocking. In the process of shale gas development, attention should be paid to the interaction between fracturing fluid and rock components in order to release more non-connected pores. Therefore, to increase shale gas extraction efficiency, more effort should be directed towards identifying natural, and creating induced, porosity.
•Non-connected pore fractions of the studied shale are obtained from complementary approaches.•The shale pore system was quantified using NMR and NMRc methods, with measurable pore diameters down to 4.25 nm.•Non-connected pores, which are mainly in organic matter, constitute 17–40% of total pore volume and have diameters of 5~31 nm.
Waterflooding experiments were conducted in micro-models (microscopic scale) and on plunger cores from low permeability, extra-low permeability and ultra-low permeability reservoirs in the Ordos ...Basin under different displacement pressures using the NMR techniques to find out pore-scale oil occurrence state, oil production characteristics and residual oil distribution during the process of waterflooding and analyze the effect of pore structure and displacement pressure on waterflooding efficiency. Under bound water condition, crude oil mainly occurs in medium and large pores in the low-permeability sample, while small pores and medium pores are the main distribution space of crude oil in extra-low permeability and ultra-low permeability samples. During the waterflooding, crude oil in the medium and large pores of the three types of samples are preferentially produced. With the decrease of permeability of the samples, the waterflooding front sequentially shows uniform displacement, network displacement and finger displacement, and correspondingly the oil recovery factors decrease successively. After waterflooding, the residual oil in low-permeability samples is mainly distributed in medium pores, and appears in membranous and angular dispersed phase; but that in the extra-low and ultra-low permeability samples is mainly distributed in small pores, and appears in continuous phase formed by a bypass flow and dispersed phase. The low-permeability samples have higher and stable oil displacement efficiency, while the oil displacement efficiency of the extra-low permeability and ultra-low permeability samples is lower, but increases to a certain extent with the increase of displacement pressure.
The presynaptic active zone proteins UNC-13/Munc13s are essential for synaptic vesicle (SV) exocytosis by directly interacting with SV fusion apparatus. An open question is how their association with ...active zones, hence their position to Ca(2+) entry sites, regulates SV release. The N-termini of major UNC-13/Munc13 isoforms contain a non-calcium binding C2A domain that mediates protein homo- or hetero-meric interactions. Here, we show that the C2A domain of Caenorhabditis elegans UNC-13 regulates release probability of evoked release and its precise active zone localization. Kinetics analysis of SV release supports that the proximity of UNC-13 to Ca(2+) entry sites, mediated by the C2A-domain containing N-terminus, is critical for accelerating neurotransmitter release. Additionally, the C2A domain is specifically required for spontaneous release. These data reveal multiple roles of UNC-13 C2A domain, and suggest that spontaneous release and the fast phase of evoked release may involve a common pool of SVs at the active zone. DOI: http://dx.doi.org/10.7554/eLife.01180.001.
The pore structure characteristic parameters of vuggy carbonate reservoirs were extracted, and matrix resistivity of vuggy reservoir was calculated by the percolation network simulation. A segmented ...cross-scale resistivity calculation method was established, in which the finite element method was used to simulate the resistivity of vuggy reservoirs. The mathematical models of vug porosity and water saturation with rock resistivity in vuggy carbonate reservoir were established, and the relationships between them were obtained. Experimental results verified the reliability of the simulation results. The method presented provides new technical means and research method for the resistivity log interpretation of vuggy carbonate reservoirs. The matrix porosity, vug porosity and matrix pore water saturation are the key factors determining the resistivity of reservoir rocks.
Presynaptic ligand-gated ion channels (LGICs) have long been proposed to affect neurotransmitter release and to tune the neural circuit activity. However, the understanding of their in vivo ...physiological action remains limited, partly due to the complexity in channel types and scarcity of genetic models. Here we report that
LGC-46, a member of the Cys-loop acetylcholine (ACh)-gated chloride (ACC) channel family, localizes to presynaptic terminals of cholinergic motor neurons and regulates synaptic vesicle (SV) release kinetics upon evoked release of acetylcholine. Loss of
prolongs evoked release, without altering spontaneous activity. Conversely, a gain-of-function mutation of
shortens evoked release to reduce synaptic transmission. This inhibition of presynaptic release requires the anion selectivity of LGC-46, and can ameliorate cholinergic over-excitation in a
model of excitation-inhibition imbalance. These data demonstrate a novel mechanism of presynaptic negative feedback in which an anion-selective LGIC acts as an auto-receptor to inhibit SV release.
Neuropeptides play crucial roles in modulating neuronal networks, including changing intrinsic properties of neurons and synaptic efficacy. We previously reported a Caenorhabditis elegans mutant, ...acr-2(gf), that displays spontaneous convulsions as the result of a gain-of-function mutation in a neuronal nicotinic acetylcholine receptor subunit. The ACR-2 channel is expressed in the cholinergic motor neurons, and acr-2(gf) causes cholinergic overexcitation accompanied by reduced GABAergic inhibition in the locomotor circuit. Here we show that neuropeptides play a homeostatic role that compensates for this excitation-inhibition imbalance in the locomotor circuit. Loss of function in genes required for neuropeptide processing or release of dense core vesicles specifically modulate the convulsion frequency of acr-2(gf). The proprotein convertase EGL-3 is required in the cholinergic motor neurons to restrain convulsions. Electrophysiological recordings of neuromuscular junctions show that loss of egl-3 in acr-2(gf) causes a further reduction of GABAergic inhibition. We identify two neuropeptide encoding genes, flp-1 and flp-18, that together counteract the excitation-inhibition imbalance in acr-2(gf) mutants. We further find that acr-2(gf) causes an increased expression of flp-18 in the ventral cord cholinergic motor neurons and that overexpression of flp-18 reduces the convulsion of acr-2(gf) mutants. The effects of these peptides are in part mediated by two G-protein coupled receptors, NPR-1 and NPR-5. Our data suggest that the chronic overexcitation of the cholinergic motor neurons imposed by acr-2(gf) leads to an increased production of FMRFamide neuropeptides, which act to decrease the activity level of the locomotor circuit, thereby homeostatically modulating the excitation and inhibition imbalance.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Primary aldosteronism (PA) is associated with a higher prevalence of abdominal aortic calcification (AAC). Unilateral and bilateral PA are the most common subtypes of PA. However, no studies have ...addressed the difference in the prevalence of AAC between the two subtypes. In addition to aldosterone, parathyroid hormone (PTH), an important regulator of calcium metabolism, was also reported to be elevated in individuals with unilateral PA. Therefore, we hypothesized that the prevalence of AAC may be higher in individuals with unilateral PA, which may be related to the plasma aldosterone concentration (PAC) and PTH levels. We included 156 PA patients who underwent adrenal venous sampling and 156 with essential hypertension (EH) matched by age and sex. Of the former, 76 were diagnosed with unilateral PA, and 80 were diagnosed with bilateral PA. The aortic calcification index (ACI) presented the severity of AAC and was measured by adrenal computed tomography scan. Our results showed that compared with the EH group, the prevalence and severity of AAC were higher in PA patients (32.7 vs. 19.6%; 4.32 ± 3.61% vs. 2.53 ± 2.42%, respectively). In the PA subgroup analysis, unilateral PA was associated with a higher and more severe AAC than bilateral PA (40.7 vs. 25.0%; 5.12 ± 4.07% vs. 3.08 ± 2.34%, respectively). Moreover, PAC and PTH levels were higher in individuals with unilateral PA than in those with bilateral PA (P < 0.05). After risk adjustment, multivariate regression analysis revealed that PAC and PTH were positively-associated with AAC in patients with PA (P < 0.05). In conclusion, unilateral PA patients exhibited a higher prevalence of AAC and more severe AAC due to elevated PAC and PTH levels.
Excitation-inhibition imbalance in neural networks is widely linked to neurological and neuropsychiatric disorders. However, how genetic factors alter neuronal activity, leading to ...excitation-inhibition imbalance, remains unclear. Here, using the C. elegans locomotor circuit, we examine how altering neuronal activity for varying time periods affects synaptic release pattern and animal behavior. We show that while short-duration activation of excitatory cholinergic neurons elicits a reversible enhancement of presynaptic strength, persistent activation results to asynchronous and reduced cholinergic drive, inducing imbalance between endogenous excitation and inhibition. We find that the neuronal calcium sensor protein NCS-2 is required for asynchronous cholinergic release in an activity-dependent manner and dampens excitability of inhibitory neurons non-cell autonomously. The function of NCS-2 requires its Ca2+ binding and membrane association domains. These results reveal a synaptic mechanism implicating asynchronous release in regulation of excitation-inhibition balance.
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•Chronic neuronal activation causes asynchronous presynaptic release•Persistent asynchronous release correlates to low excitability of downstream neurons•Excitation-inhibition imbalance depends on the neuronal Ca2+ sensor protein NCS-2•The function of NCS-2 depends on Ca2+ binding and membrane association
Zhou et al. show that asynchronous vesicle release due to sustained neuronal activation leads to excitation-inhibition imbalance in a C. elegans neuronal circuit and that this is dependent on the neuronal Ca2+ sensor protein NCS-2.
In recent years, a series of major natural gas exploration discoveries and breakthroughs have been achieved in deep and ultra-deep carbonate gas reservoirs in the Sichuan Basin, and all discovered ...gas reservoirs are characterized by great burial depth, complex pore structures and high formation temperature and pore pressure. In order to accurately predict the gas flow rate of single well in high temperature and high pressure (HTHP) gas reservoirs and clarify the gas flow characteristics under formation conditions, this paper establishes a productivity simulation experimental device and method based on the formation temperature and pore pressure of carbonate gas reservoirs in the Middle Permian Qixia Formation of northwestern Sichuan Basin and the Upper Sinian Dengying Formation of central Sichuan Basin. Then, the cores of above mentioned gas reservoirs are selected to carry out the productivity simulation experiment under HTHP. Finally, the gas flow characteristics are studied. And the following research results are obtained. First, the newly established productivity simulation experimental device and method suitable for the conditions of 160 °C formation temperature and 100 MPa pore pressure is used to predict the natural gas AOF (absolute open flow) of Well S-1 in the Qixia Formation gas reservoir of northwestern Sichuan Basin. And the prediction result is better accordant with the calculation result of theoretical model, with a relative error of only 2.12%. Second, based on the Klinkenberg permeability under surface conditions, the single-well gas flow rate calculated from the productivity simulation experiment is better accordant with the gas flow rate from field completion testing; while based on the Klinkenberg permeability under formation conditions, the single-well gas flow rate calculated from the productivity simulation experiment is better accordant with the AOF. Third, the change of formation temperature and pore pressure has a significant influence on rock permeability, and the permeability is more sensitive to stress than to temperature. Fourth, to carry out the reservoir stress sensitivity experiment and the productivity simulation experiment, it is required that core samples be recovered to the formation conditions for aging, or the experimental results may have characteristics of strong stress sensitivity and cannot be used for reservoir engineering evaluation directly. In conclusion, the production rate and AOF of HTHP gas wells can be predicted accurately by means of productivity simulation experiment, based on drilling core samples. In addition, the Klinkenberg permeability under formation conditions can be evaluated by using the relational expression between surface or Klinkenberg permeability under formation conditions and single-well gas flow rate, combined with gas well testing data.
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