Towards Compact Modeling of Noisy Quantum Computers: A Molecular-Spin-Qubit Case of Study

Classical simulation of Noisy Intermediate Scale Quantum computers is a crucial task for testing the expected performance of real hardware. The standard approach, based on solving Schrödinger and Lindblad equations, is demanding when scaling the number of qubits in terms of both execution time and memory. In this article, attempts in defining compact models for the simulation of quantum hardware are proposed, ensuring results close to those obtained with standard formalism. Molecular Nuclear Magnetic Resonance quantum hardware is the target technology, where three non-ideality phenomena—common to other quantum technologies—are taken into account: decoherence, off-resonance qubit evolution, and undesired qubit-qubit residual interaction. A model for each non-ideality phenomenon is embedded into a MATLAB simulation infrastructure of noisy quantum computers. The accuracy of the models is tested on a benchmark of quantum circuits, in the expected operating ranges of quantum hardware. The corresponding outcomes are compared with those obtained via numeric integration of the Schrödinger equation and the Qiskit’s QASMSimulator. The achieved results give evidence that this work is a step forward towards the definition of compact models able to provide fast results close to those obtained with the traditional physical simulation strategies, thus paving the way for their integration into a classical simulator of quantum computers.

Three-Dimensional Physical Simulation of Heavy Oil Exploitation by Hot Solvent Injection

To improve the thermal effects of solvents on heavy oil reservoirs and realize the combined action of multiple flooding mechanisms, such as solvent heating and extraction, without steam mixing, based on the M Block heavy oil reservoir in Canada, three sets of comparative hot solvent-assisted gravity drainage experiments under different temperatures and pressures were carried out through an indoor three-dimensional (3D) physical simulation device. The development characteristics of the solvent chamber in the hot solvent-assisted gravity drainage technology were studied under different pressures and temperatures, and the recovery factor, cumulative oil exchange rate, and solvent retention rate were analyzed. The results showed that due to the effect of gravity differentiation, the development morphology of the solvent chamber could be divided into three stages: rapid ascent, lateral expansion, and slow descent. When the temperature was constant, the reservoir pressure decreased, the recovery rate increased, the cumulative oil exchange rate increased, and the solvent retention rate decreased; when the pressure was constant, the temperature increased, the viscosity of heavy oil decreased, the recovery rate increased, the cumulative oil exchange rate increased, and the solvent retention rate was low. Additionally, the study also showed that for hot solvents in different phases, the use of hot solvent vapor not only required less injected solvent but also exhibited a high oil production rate, which shortened production time and reduced energy consumption. Moreover, the oil recovery rate was higher than 60%, the solvent retention rate was lower than 10%, and the cumulative oil exchange rate was higher than 3 t / t , which constituted better economic benefits and provided a reliable theoretical basis for onsite oilfield applications.

Complex Function Solution for Deformation and Failure Mechanism of Inclined Coal Seam Roadway

The stressed environment of the inclined coal seam roadway is complex and changeable, and the damage degree of surrounding rock increases, threatening the safe mining of coal mines. To improve the effectiveness of stability control of surrounding rock of this kind of roadway, the deformation and failure law of the inclined coal seam roadway is analyzed based on the complex function theory. It optimizes the solution process and accuracy of the mapping function coefficient and deduces the analytical solution of surrounding rock stress and deformation inclined coal seam roadway. The deformation and failure mechanism of surrounding rock in inclined coal seam roadway is revealed theoretically and verified by numerical simulation and physical simulation test. The results show that the stress and deformation of roadway surrounding rock in inclined coal seam show obvious asymmetric distribution characteristics. The stress and deformation of roadway surrounding rock on the right side are greater than on the left side. The two sides of the roadway, the right side of the roof and the roof angle of the right side, are the key positions of roadway stress concentration and deformation. According to the variation law of stress and deformation distribution of roadway surrounding rock, roadway cyclic deformation and failure theory is put forward. The numerical simulation and physical simulation test show that the deformation and failure law of roadway is consistent with the theoretical analysis results, and the cyclic deformation and failure mechanism of roadway in inclined coal seam is verified.

Techno-economic aspects and problems of the rotary rowing units introduction in the modernization and construction of ships (on the example of projects 1809 and CNF11CPD)

The article contains a detailed analysis of studies related to the use of existing and new principles of fuel economy, and reducing the cost of re-equipment and operation of vessels of the above projects. The authors of the article did not set out to analyze the technical features of these projects. Only by linking to these projects, the analysis was done for the entire fleet of this type as a whole. A technical and economic analysis of the characteristics, modeling of the main and auxiliary installations in the Matlab package, providing fuel economy on the example of ships of projects 1809 and CNF11CPD, is carried out. Then a physical simulation was carried out. As a result of testing a vessel with a rotary rowing electric installation (RSEU), a qualitative analysis of the data obtained was carried out, conclusions were drawn that allow us to judge the possibility of large-scale use of such installations in maritime transport.

Internal model control for rocket launcher position servo system based on improved wavelet neural network

This paper proposes an improved wavelet neural network-internal model controller (WNN-IMC) for the rocket launcher position servo system. Due to complex nonlinearities and uncertainties of external disturbances in the rocket launcher position servo system, it is vitally challenging to establish its accurate model by the mechanical modeling technique. A wavelet neural network (WNN) identification method is proposed to determine the system mathematical model through test datum, which optimized by the hybrid algorithm of differential evolution (DE) and particle swarm optimization (PSO). Then, the proposed method is applied to identify the semi-physical simulation platform of the rocket launcher velocity servo system. The results demonstrate that the validity of the DEPSO-WNN method is better than that of the WNN and PSO-WNN methods. Finally, compared with the WNN-IMC controller and the ADRC controller, the effectiveness of the improved WNN-IMC controller is verified by the semi-physical simulation experiments.

New Online Shunt Acidification for Water Injection Increasing Technology and Its Application in Huanjiang Oilfield

The poor physical property and strong heterogeneity of Triassic Yanchang formation in Huanjiang oilfield of Ordos Basin are the main reasons for uneven water absorption, partial injection wells underinjection at high pressure, and decline of production. Previously, large numbers of conventional acidifications were used for plugging removal in the reservoir, but the effect was not so good and effective period was short. Aiming at the geological characteristics of Huanjiang oilfield, an online shunt acidification and augmented injection technology which does not stop water injection, pull original production strings out, and continuously inject acid and diverting agent has been proposed. A chelating acid COA-1S with low corrosion rate (0.3675 g/(m2·h)), good retardation capacity (hydrolysis constant = 1.2 × 10−6), and effective chelating ability (precipitation inhibition rate >95%) has been developed, as well as a diverting agent COA-1P with good dispersion in acid solution, diversion effect, and particle size (10–100 μm), which behaves well in COA-1S acid. It has been proved that the online acid system has a good diversion acidizing ability and plugging removal performance in a deep area in the laboratory core physical simulation test. The field test results show that the online shunt acidizing and augmented injection technology could reduce the injection pressure significantly (4.2 MPa) and increase water injection by 10 m3/d for the measured well (H5) and improve the water injection profile prominently. The online shunting acidification and augmented injection technology have the following advantages: simple procedures, fewer equipment needed, high efficiency of depressurization, and increasing water injection, which could effectively improve the profile of water wells, and there is a bright future of the technology.

Physical Simulation Test on Surrounding Rock Deformation of Roof Rockburst in Continuous Tunneling Roadway

To study the occurrence process, as well as the temporal and spatial evolution laws, of rockburst disasters, the roof deformation of continuous heading roadways during rockburst was studied through a physical similarity simulation test with a high similarity ratio and low strength. The deformation and failure evolution law of the roadway roof in the process of rockburst were analyzed by using detection systems, including a strain acquisition system and a high-power digital micro-imaging system. The results show that the rockburst of the roadway roof can be divided into four stages: equilibrium, debris ejection, stable failure, and complete failure stage. According to the stress state of a I–II composite crack, the theoretical buckling failure strength of the surrounding rock is determined as 1.43 times the tensile strength. The flexural failure strength of a vanadium-bearing shale is 1.29–1.76 times its compressive strength. With continuous advancement in the mining time, the internal expansion energy of the roadway roof-surrounding rock in the equilibrium stage continuously accumulates. The fracture network continuously increases, developing to the stable failure stage, with bending deformation, accompanied by continuous particle ejection until the cumulative stress in the failure stage increases, and the tensile state of the rock surrounding the roof expands radially into deep rock. A microscopic damage study in similar material demonstrated that the deformation of the roadway roof is non-uniform and uncoordinated. In the four stages, the storage deformation of the rock surrounding the roadway roof changes from small accumulation to continuous deformation, to the left (or deep rock). Finally, the roadway roof-surrounding rock becomes completely tensioned. The research results presented in this study provide a reference for the prediction and control of rockburst in practical engineering.

Research on the Relationship Between the Pore Structure Characteristics of Reservoir and Performance of Cr3+ Polymer Gel

Cr3+ polymer gel flooding technology is very important for enhancing oil recovery and its field trails have obtained significantly oil increment effect. However, its laboratory physical simulation experiments are rarely carried out according to real reservoir conditions. Therefore, it is very important to carry out relevant research work. Aiming at the reservoir condition of Bohai Oilfield (an offshore oilfield in China), the experimental studies on the pore structure characteristics of reservoir on the properties of Cr3+ polymer gel are carried out. The effect of different core permeability (500, 1500 and 5000 ×10−3μm2), clay content (4.5%, 9.0% and 18%), mineral type (kaolinite, montmorillonite and illite), oil saturation (79.2%, 65.4% and 49.3%) and dynamic gelation effect are thoroughly studied. Finally, its application is introduced and analyzed. Research results show that, with the increase of reservoir permeability and pore throat size, the gelation effect improves. Also, the loose cementation degree is helpful for rapid gelation. In additional, with the decrease of the content of clay and oil saturation, the gelforming effect gets better. However, the dynamic gelation strength is very low in porous media. And after chemical injection, suspension of water flooding could promote the gel-forming performance. From the field test results, this technology has obtained good effect in Bohai oilfield, due to the high permeability, severe heterogeneity, loose cementation and high water cut. In conclusion, it is very important to study on the gelation effect under the real reservoir conditions deeply. Therefore, the relevant experimental studies have been carried out comprehensively. And its mechanism are further explored. Furthermore, its field application has also been also summarized, which is vital to the success of this technology.

Ground Pressure under Mining Ore Bodies of Different Angles Based on Physical Simulation

Ground pressure characteristics of the ore body and the overburden deformation of the stope depend highly on the combined influence of geological conditions and mining disturbance. The ore body inclination, as a natural geological factor, has a nonnegligible effect on the underground mining. The ore angle plays a great role in the stress distribution of the overlying rock layer, resulting in the movement and destruction of the rock layer. The variation of the ore angle dominates the stress distribution of the overburden rock, the forms of movement, destruction, and the surface moving basin. Here, taking the geological mining conditions of the deep ore body mining in Jinning Phosphate Mine as the engineering background, we adopt a similar material ratio scheme of each rock layer in the mining area via the similarity theory and the principle of orthogonal experiment. We conduct systematic study on the strata movement, mining failure characteristics, and movement of the overlying rock in stope using a similar simulation test under two different ore angles of 20° and 50°. We found that, as the ore body inclination increases from 20° to 50°, the overburden unloading area of the stope extending to the deep part of the rock layer in the vertical direction is more obvious and its shape is more asymmetric about the stope center. The unloading area is more concentrated in the middle and upper part of the stope, while the upward development trend is more obvious. The relevant results can provide a certain reference for the underground mining of the mines and those with similar conditions.