Development Of High Efficiency Research Articles

A comparative study of mean-line models based on enthalpy loss and analysis of a cavity-structured radial turbine for solar hybrid microturbine applications

Lightweight components are essential for the future of the energy and aerospace fields. This paper presents an innovative radial turbine design that utilizes a cavity structure on the rotor for solar hybrid microturbines. The performance of the cavity-structured radial turbine is studied using mean-line models, computational fluid dynamics (CFD), and finite element analysis (FEA) simulations. The radial turbine is compared using air and supercritical carbon dioxide (sCO2) as the working fluid. The mean-line models based on enthalpy losses from recent literature are validated using commercial code Rital and CFD results. The impact of the isentropic velocity ratio (νs) and absolute flow angle at the rotor inlet (α1) on the optimum design for the rotor radial turbine is also demonstrated. A comparative loss enthalpy breakdown on the rotor is examined, such as incidence loss, passage loss, trailing edge loss, clearance loss, exit loss, and windage loss. The results show that the recent mean-line models based on enthalpy losses can accurately estimate the stage efficiency for both air and sCO2 turbines. By comparing the simulation results obtained from 3D-CFD and mean-line models, the efficiency prediction deviation is within an acceptable range of tolerance for both turbines when comparing the results obtained from 3D-CFD and mean-line models. The FE analysis reveals that the maximum stress decreased significantly for the air and sCO2 turbine after the rotor blade was added using the cavity structure inside. The maximum stress value on the rotor with the cavity structure design is still below the yield strength of the material limits. Furthermore, after the variations of the cavity structure design were added to the rotor blade of both turbines, the results were promising when the dangerous resonance at below 4EO (Engine Order) was minimized. The results of this study provide a promising direction for the development of high-efficiency and lightweight turbines in the energy and aerospace fields.

A review of influencing factors on a recirculating aquaculture system: Environmental conditions, feeding strategies, and disinfection methods

AbstractRecirculating aquaculture system (RAS), as a modern highly intensive aquaculture mode, demonstrates the advantages of environmental friendliness, high efficiency and sustainable development, and has been widely used worldwide; they are also expected to be more widely applied in industrial aquaculture in the future as our natural resources are decreasing. However, RAS imposes very high requirements on operating conditions, including temperature, salinity, dissolved oxygen, pH, stocking density, light, feed composition, feeding amount, feeding frequency, and disinfection methods. Each factor is critical to the stable operation of the system. Therefore, to ensure the efficient and stable operation of RAS, its influencing factors must be controlled to within appropriate ranges. Herein, the factors affecting the operation of RAS are reviewed, and the mechanisms of their influence on the reared organisms are revealed, and suggestions on the control of these factors in aquaculture are proposed. This review can provide a theoretical basis for the further development of RAS.

Reduced graphene oxide composite Ni3S2 microspheres grown directly on nickel foam as an efficient electrocatalyst for OER

The development of cheap, high-efficiency, and stable oxygen evolution reaction (OER) electrocatalysts is a current research hotspot. In this work, reduced graphene oxide (rGO) composite Ni3S2 microspheres grown directly on nickel foam (Ni3S2-rGO/NF) were prepared by tube furnace calcination and hydrothermal method. The Ni3S2-rGO/NF had excellent OER catalytic activity and stability with an overpotential of 303 mV at the current density of 100 mA cm−2, which was 100 mV lower than that of Ni3S2/NF, and its Tafel slope was as low as 23 mV·dec−1. The main reason for enhancing OER activity of the Ni3S2-rGO/NF is due to synergistic effect of Ni3S2 microspheres and rGO, which inhibited the production of NiS and refined the micron size of Ni3S2. This work offers a new method for developing stable and efficient OER catalysts.

Hierarchical Model Updating Method for Vector Electric-Propulsion Satellites

Electric propulsion is of great significance to the development of high-efficiency and long-life satellites, and digital twins have gradually become a powerful tool for satellite engineering. Being affected by uncertainty factors such as the complexity and variability of the space environment and the satellite system, the digital twin model cannot accurately reflect the real physical properties. Therefore, it is crucial to update the satellite model to improve prediction accuracy. However, the complex structure and multi-physics process coupling of vector electric-propulsion satellites bring great challenges to model updating. According to the characteristics of the vector electric-propulsion satellite, this paper establishes mathematical models of the whole satellite. Additionally, a hierarchical model updating method is proposed and applied to the model updating case of a satellite with multiple subsystems. The simulation results show that the method is suitable for the model updating of the vector electric-propulsion satellite. Through multiple iterations of closed-loop cycles, the residual errors between the simulation values and the telemetry values can be decreased, and the errors between the estimated values and the true values of state variables can also be decreased by an order of magnitude.

Electrocatalytic Overall Water Splitting Induced by Surface Reconstruction of an Iron-Modified Ni2P/Ni5P4 Heterojunction Array Encapsulated into a N-Doped Carbon Layer

Reasonable development of high-efficiency and robust electrocatalysts for efficient electrocatalytic water splitting at high current density is hopeful for renewable energy, but the real challenge is substituting the precious metal catalysts. Herein, ultrathin Fe-modified Ni2P/Ni5P4 nanosheet arrays hybridized with N-doped carbon grown on Ni foam (Fe-Ni2P/Ni5P4@N-C) were synthesized via a solvothermal-pyrolysis strategy. Theoretical calculations and in situ Raman characterizations confirm that the Fe sites can facilitate the surface reconstruction of highly active NiOOH species and significantly lower the energy barrier for the formation of the *OOH intermediate owing to the electron coupling effect between Fe and the Ni2P/Ni5P4 heterostructure. On account of the structural advantages and compositional synergy, the optimized Fe-Ni2P/Ni5P4@N-C exhibits superior hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) activities with an overpotential of 105 and 280 mV to reach 10 and 50 mA cm-2, respectively, and can work stably for 60 h at 100 mA cm-2. Impressively, the electrolyzer with Fe-Ni2P/Ni5P4@N-C only needs 1.56 V to achieve 10 mA cm-2 current density for water splitting. This protocol not only provides inspiration for designing transitional metal electrocatalysts for water splitting but also puts forward a pathway for practical application.

Loss analysis of magnetization annealed amorphous alloy replacement stator teeth

With the development of electric motors, high speed and high efficiency have become the new development trend. Therefore, reducing the iron loss of motors has become the focus of academia and industry. Amorphous alloys are gradually being used in high speed motors by virtue of their low loss characteristics at high frequencies. Amorphous alloys generate large internal stresses during the manufacturing process, and annealing is usually required to eliminate the effect of internal stresses on magnetism. Amorphous transformer cores are usually annealed by applying a magnetic field in the direction of the magnetic circuit to improve the magnetic domain state, increase the saturation density in that direction, and reduce iron loss. Since the magnetic field of the motor stator teeth is pulsating, and amorphous annealed under longitudinal magnetic field (AALM) has the most performance along the direction of the annealed magnetic field. Therefore, in this paper, the magnetic properties of AALM, annealed amorphous (AA), and unannealed amorphous (UA) are tested to prove the advantages of the material, and then AALM is spliced as the tooth of the motor. The advantages of this material in the motor species are further demonstrated by designing a comparative simulation scheme in the longitudinal direction (same material with different structure) and in the transverse direction (same structure with different material).

Thermoeconomic appraisal of a novel power and hydrogen cogeneration plant with integration of biomass and geothermal energies

The present research aims at development and design of a new high-efficiency power/hydrogen co-production framework running by biomass/geothermal renewable resources. In this regard, to attain global energy transition goals based on green hydrogen utilization of renewable resources instead of conventional fossil fuel-based routes for hydrogen production is followed. The proposed system structure consists mainly of a gas turbine coupled to a geothermal assisted Rankine unit which extracts the gas turbine wasted heat to run a water electrlyzer for H2 production. To illustrate a comprehensive performance evaluation, technical (thermodynamic), environmental and economic aspects are considered and assessed. Eight performance indices are evaluated including: power and hydrogen productions, thermal and exergetic efficiencies, environmental damage and emission index, LCOP and overall system cost. In addition, a bi-objective optimization is implemented with respect to efficiency and product cost. Results show that, the cogeneration framework under optimum condition, operates with exergetic efficiency of 42.37% and levelizedproductcostof68.52$/MWh, whose emitted CO2 is 0.7443kg/kWh. Also, compared to basic design point conditions, it is found out that optimization leads to performance enhancements by 7.5%, 9.0% and 7.7% for the three mentioned indicators, respectively.

Influence of Ionic Additives in the PEDOT:PSS Hole Transport Layers for Efficient Blue Perovskite Light Emitting Diodes.

Ruddlesden-Popper (RP) perovskites have been gaining traction in the development of high-efficiency or blue-emitting perovskite light emitting diodes (PeLEDs) due to the unique energy funneling mechanism, which enhances photoluminescence intensity, and dimensional control, which enables spectral tuning. In a conventional p-i-n device structure, the quality of RP perovskite films, including grain morphology and defects, as well as device performance can be significantly influenced by the underlying hole-transport layer (HTL). Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is commonly used in several PeLEDs as an HTL because of its high electrical conductivity and optical transparency. Nonetheless, the energy level mismatch and exciton quenching caused by PEDOT:PSS often compromises PeLED performance. Herein, we investigate the mitigation of these effects through addition of work-function-tunable PSS Na to the PEDOT:PSS HTL and assess the impact on blue PeLED performance. Surface analysis of the modified PEDOT:PSS HTLs reveals a PSS-rich layer that alleviates exciton quenching at the HTL/perovskite interface. At an optimal concentration of 6% PSS Na addition, an improvement in the external quantum efficiency is observed, with champion blue and sky-blue PeLEDs achieving 4% (480 nm) and 6.36% (496 nm), respectively, while operation stability is prolonged by fourfold.

Carbon nanotube membrane armed with confined iron for peroxymonosulfate activation towards efficient tetracycline removal

The water treatment performance of metal-based peroxymonosulfate (PMS) catalytic membrane is always limited by the finite residence time and complex water matrixes. Therefore, the development of high efficiency and anti-interference PMS catalytic membrane is of great significance. In this work, an oxidized carbon nanotube membrane with Fe2O3 nanoparticle confined inside (Fe2O3@OCNT) has been fabricated for enhanced PMS activation in the membrane filtration process (MFPA process). The experiment results showed that through fine-tuning the confinement degree of Fe2O3 in OCNT, the non-radical electron transfer pathway was gradually enhanced and became the dominant process. Under the suitable confinement condition, the tetracycline (TC) removal in the Fe2O3@OCNT MFPA process was up to 96.1 % with a residence time of only 8.0 s, which remarkably outperformed the powder-based or batch process. The high efficiency of the membrane was attributed to the enhanced mass transfer and non-radical electron transfer process due to the nanoconfinement effect. This was supported by theoretical calculations, where it was showed that confining Fe2O3 inside OCNT not only enhanced the electron activity in the lumen of OCNT, but also increased the adsorption energy for PMS. In addition, the four possible degradation pathways of TC were proposed based on Fukui function analysis and LC-MS results. This system displayed reusability and good stability for TC removal (5 cycles > 85 %, low Fe leaching of 10 μg·L-1, and long-term running of 48 h) and wide applicability for different pollutants, while also demonstrated unique anti-interference property in the presence of inorganic ions and in real water matrixes.

Theory and practice of unconventional gas exploration in carrier beds: Insight from the breakthrough of new type of shale gas and tight gas in Sichuan Basin, SW China

Unconventional gas in the Sichuan Basin mainly includes shale gas and tight gas. The development of shale gas is mainly concentrated in the Ordovician Wufeng Formation–Silurian Longmaxi Formation, but has not made any significant breakthrough in the Cambrian Qiongzhusi Formation marine shale regardless of exploration efforts for years. The commercial development of tight sandstone gas is mainly concentrated in the Jurassic Shaximiao Formation, but has not been realized in the widespread and thick Triassic Xujiahe Formation. Depending on the geological characteristics of the Qiongzhusi Formation and Xujiahe Formation, the feedback of old wells was analyzed. Then, combining with the accumulation mechanisms of conventional gas and shale gas, as well as the oil/gas shows during drilling, changes in production and pressure during development, and other characteristics, it was proposed to change the exploration and development strategy from source and reservoir exploration to carrier beds exploration. With the combination of effective source rock, effective carrier beds and effective sandstone or shale as the exploration target, a model of unconventional gas accumulation and enrichment in carrier beds was built. Under the guidance of this study, two significant results have been achieved in practice. First, great breakthrough was made in exploration of the silty shale with low organic matter abundance in the Qiongzhusi Formation, which breaks the traditional approach to prospect shale gas only in organic-rich black shales and realizes a breakthrough in new areas, new layers and new types of shale gas and a transformation of exploration and development of shale gas from single-layer system, Longmaxi Formation, to multi-layer system in the Sichuan Basin. Second, exploration breakthrough and high-efficient development were realized for difficult-to-produce tight sandstone gas reserves in the Xujiahe Formation, which helps address the challenges of low production and unstable production of fracture zones in the Xujiahe Formation, promote the transformation of tight sandstone gas from reserves without production to effective production, and enhance the exploration and development potential of tight sandstone gas.

Oxygen vacancies modified MnS/MnO2 heterostructure anode catalyst for efficiently electrocatalytic removal of dye wastewater

Electrochemical advanced oxidation processes (EAOPs) are favorable technologies to remove organic wastewater, but the development of high-efficiency and low-energy consumption anode catalysts is still a priority. Herein, a carbon cloth-supported MnS/MnO2 heterostructure rich in oxygen vacancies is successfully synthesized as an anode for the electrocatalytic removal of methyl orange (MO) wastewater. The anode catalyst possesses lower charge transfer resistance (77.4 Ω), higher oxygen evolution potential (2.13 V vs RHE), and removes nearly 100% methyl orange (20 mg/L) in 30 min with a high mineralization current efficiency of 73.2% and low energy consumption of 23.4 kWh/kg TOC. Through density functional theory (DFT) studies, oxygen vacancies increase the positive charge of Mn atoms in the vicinity of the heterostructure interface, thus improving its catalyst activity. The calculated adsorption energy of H2O (ΔEH2O) is reduced from − 0.672 eV for MnO2 to − 0.887 eV for oxygen-vacancy heterostructure, which is conducive to the water splitting to form •OH. Overall, this study provides a promising strategy for enhancing the electrocatalytic removal performance of manganese dioxide by using heterostructure design and oxygen vacancy engineering.

Multi crop high efficiency seed drill with solar hybrid seed metering: A step toward precision and sustainability

High crop production with limited energy resources is always the priority area of developing countries. Conventional agricultural experimenting and crop production methods are time-consuming, challenging, laborious, and energy intensive. Various developments and experimental studies have been carried out for advancement in agriculture technologies. This study is mainly focused on the design and development of a unique high-efficiency seed drill machine to increase the energy efficiency of agricultural experiments, and crop production and conserve the tillage, seed, fertilizer, and power requirement. This machine has a special seed dividing head and seed distributor triggered with a mechanical timer. The mechanical timer is responsible to deliver seed to the seed distributor as per fixed plotting intervals. The seed distribution unit distributes the seeds uniformly in all furrows as per the pre-decided seed rate aided with a centrifugal glider aided with a DC motor powered by a 30 W solar PV plate and backup battery. Moreover, the machine has 9 × 9 s-type spring tines for seed and fertilizer, which are mainly designed for better soil pulverization and aeration with significant in-field resource conservation as per conventional alternatives. The effective width is seven feet and adjustable rows with versatile seed rate options. Overall, the results from different field tests verified the uniform seed dispersal with improved germination rate. The analysis of power requirements compared to conventional machines results in the 40% less power requirement. Overall, the machine has customized unique features for experiments and energy-efficient precision agriculture to conserve input resources.

Lightweight Multi-scale Convolutional Neural Network for Rice Leaf Disease燫ecognition

In the field of agricultural information, the identification and prediction of rice leaf disease have always been the focus of research, and deep learning (DL) technology is currently a hot research topic in the field of pattern recognition. The research and development of high-efficiency, high-quality and low-cost automatic identification methods for rice diseases that can replace humans is an important means of dealing with the current situation from a technical perspective. This paper mainly focuses on the problem of huge parameters of the Convolutional Neural Network (CNN) model and proposes a recognition model that combines a multi-scale convolution module with a neural network model based on Visual Geometry Group (VGG). The accuracy and loss of the training set and the test set are used to evaluate the performance of the model. The test accuracy of this model is 97.1% that has increased 5.87% over VGG. Furthermore, the memory requirement is 26.1 M, only 1.6% of the VGG. Experiment results show that this model performs better in terms of accuracy, recognition speed and memory size.

NiPd co-doped nitrogen-coordinated graphene as a high-efficiency electrocatalyst for oxygen reduction reactions: a first-principles determination.

High-energy-density fuel cells and metal-air batteries are difficult to commercialize on a large scale mainly because of the sluggish oxygen reduction reaction (ORR) at the cathode. Hence, the development of high-efficiency and low-cost electrocatalysts as Pt substitutes for the ORR is of significance for the mass applications of these devices. In this work, we thoroughly investigated the structural and catalytic properties of NiPd co-doped N-coordinated graphene (denoted as NiPdN6-G) as an ORR electrocatalyst by using density-functional theory (DFT) calculations. Our results show that NiPdN6-G is structurally and thermodynamically stable. Furthermore, we explored all the possible paths and intermediates of the ORR, and identified the preferable active sites and the most stable adsorption configurations of the intermediates and transition states. In general, there are 15 possible reaction paths, of which 8 paths have lower energy barriers than pure Pt, and the maximum energy barrier and overpotential of the ORR for the optimal path are only 0.14 eV and 0.37 V, respectively. This work demonstrates that NiPdN6-G should be a promising candidate for substituting Pt and Pt-based catalysts for the ORR in energy conversion and storage devices.

Comparative study on performance of traditional engine and hybrid and electric engine

In the past, the car brands led by Mercedes Benz are extremely popular world-widely and those cars are mainly designed using internal combustion engines. Engine technology is also innovating in real time. Today's new energy technology is representing the development of low pollution and high efficiency in our country. In China, the growth of new energy vehicles, however, is especially rapid and, as a whole, China is the largest automobile market in the world, ranking first in production and sales scale. Despite fluctuations in recent years, China has maintained a steady but increasing development trend. Since China's accession to the WTO, new energy vehicles are blooming in the world, the shares of sustainable energy bought by everyone is constantly climbing and the scale of production and sales has grown rapidly. In 2009, China surpassed the United States to become the world's largest new car consumption market, and has always maintained a high growth rate. However, traditional cars and internal combustion engine vehicles gained some denial

Promotion and inhibition effects of wax on methane hydrate formation and dissociation in water-in-oil emulsions

Clarifying the effect of wax on hydrate formation and dissociation are important for the safe and high-efficient development of deep-water oil and gas fields. In this study, a series of experiments on the effect of wax on hydrate formation and dissociation in water-in-oil emulsions were systematically studied based on the variation analysis of temperature, pressure, torque, oil–water interface area morphology and water droplet size in emulsions. Microscopic images reveal that wax crystals form shell barriers on the oil–water interface, which increases transfer resistance, and the particle focused beam reflectance illustrates that the wax crystals decrease the water droplet size, which increases the oil–water interface area in emulsions. With increasing wax concentration, the hydrate induction time and growth rate show a bimodal shape because of the dual regulation of wax in emulsions, involving the inhibition effect of the transfer barrier layer and the promotion effect of the increasing water–oil interface area. The inhibition effect on hydrate formation was dominant when the wax concentration exceeds 6 wt%, resulting in a rapid decrease in both the growth rate and conversion ratio with increasing wax concentration. Compared with the bimodal shape of hydrate formation, the inhibition effect of wax on hydrate dissociation is the dominant regulation factor. The duration of complete hydrate dissociation by depressurization increased linearly with the increasing wax concentration, which increased the operation difficulty of hydrate plug removal. These experimental results provide valuable references for hydrate risk assessment and optimization of the project design of flow assurance for deep-water oil and gas fields.

Defective Homojunction Porphyrin‐Based Metal‐Organic Frameworks for Highly Efficient Sonodynamic Therapy

Sonodynamic therapy (SDT) with non-invasiveness and high tissue-penetrating ability has attracted widespread interest in treating deep-seated tumors or infections. To enhance the treatment efficacy of SDT, the development of high-efficiency and stable sonosensitizers are still needed. Herein, a defective homojunction porphyrin-based metal-organic framework (MOF) with greatly enhanced sonocatalytic ability is easily prepared and used for SDT of osteomyelitis infected by methicillin-resistant Staphylococcus aureus (MRSA). Acetic acid and benzoic acid are chosen as modulators during the hydrothermal synthesis of porphyrin-based MOF. It is found that the crystal structure of MOF shifts from PCN-222 to PCN-224 as the amount of acetic acid increases. Interestingly, the defective PCN (D-PCN) contains a two-phase homojunction structure of PCN-222/PCN-224. The sonocatalytic reactive oxygen species production presents a volcano-type trend with increased acetic acid, among which D-PCN-2 with more content of PCN-224 has the best sonocatalytic antibacterial ability. The reduced band gap introduced a defect, and type-II homojunction structures of D-PCN-2 improve the separation of the ultrasound-triggered electron hole, which significantly enhances the SDT effect. Through a mixed linker approach, this work develops a new defect-induced homojunction MOF with great performance for SDT of MRSA-infected osteomyelitis.

Technical advances in well type and drilling & completion for high-efficient development of coalbed methane in China

Compared with the United States, Australia, Canada, and other countries, China's coalbed methane reservoir is featured by low formation pressure, low permeability, low gas saturation, and strong heterogeneity, which not only increases the difficulty of reservoir stimulation but also restricts the single well production and the recovery efficiency of coalbed methane (CBM). In view of this, the research and application of horizontal drilling and completion technology of CBM at home and abroad are reviewed to provide references and theoretical supports for the advancement of the horizontal well engineering technology of CBM in China. This paper introduces a series of horizontal drilling and completion technologies (e.g., the well type design, well structure optimization, well trajectory control, wellbore stability, completion optimization, reservoir protection, etc.). The advanced technologies and their adaptability, including screen pipe completion and stimulation with dual-layer tubular strings, radial horizontal well screen pipe completion and magnetic steering drilling, are dialectically discussed in this paper. In addition, a novel integrated engineering mode for the efficient and green development of deep CBM and coal through the underground “well factory” is proposed. The conclusions are as follows: (1) In view of the geological conditions and surface environment of the coal seam in China, the horizontal drilling and completion technologies of high rank coalbed methane should be further refined, and an integrated development for the coal measure gas is required; (2) More efforts should be made to strengthen the innovative research on horizontal drilling & completion technology for low-medium rank coals and the broken coal, so as to identify the efficient development mode for the complex coalbed methane reservoir; (3) When encountering major technical challenges during the green and efficient development of unconventional coal mines such as deep coal mines, low grade coal mines and thin coal seams in China, it is necessary to explore the development mode via in-situ conversion process based on underground “well factory” to realize the integrated green and efficient development of deep CBM and coal; (4) The high quality transformation with low-carbon and green energy in China will not only ensure national energy security, but also achieve the goal of “carbon peaking and carbon neutrality”.

Research status and development trend of layered K<italic><sub>x</sub></italic>MnO<sub>2</sub>-based cathode materials for potassium-ion batteries

<p indent="0mm">Potassium-ion batteries have the advantages of abundant resources, low price, and similar principles to lithium-ion batteries, and are currently promising candidates to replace lithium-ion batteries as large-scale energy storage systems. Cathode materials play a key role in the performance of potassium-ion batteries, among which layered K<italic>_x</italic>MnO₂-based cathode materials have attracted much attention due to their high specific capacity, environmental friendliness, low cost, and unique two-dimensional structure. However, the repeated intercalation/deintercalation of large-sized K⁺ during the charging and discharging process will lead to the structural damage, and the Jahn-Teller effect generated by Mn³⁺ can easily cause structural distortion, resulting in a rapid capacity decrease of potassium-ion batteries, which much hinders their commercial application. Beginning with the control of the layered structure of K<italic>_x</italic>MnO₂ materials, this review systematically summarizes the preparation methods of K<italic>_x</italic>MnO₂-based cathode materials, and focuses on the doping modification of K<italic>_x</italic>MnO₂-based cathode materials, including single metal doping, dual metal doping and alkali metal doping. And this paper summarizes the main challenges existing in the current research and further looks forward to its future development direction, which is expected to provide a theoretical reference for the development of high-efficiency and stable potassium-ion batteries.

Response of soil nutrients retention and rice growth to biochar in straw returning paddy fields

Applying straw to agricultural production to improve soil productivity and crop yields is significant. However, the straw-only application is possibly not a practical choice for achieving environmental protection and high yield. This study evaluated the applicability of straw combined with biochar to the paddy field. Two-year pot experiments were conducted to examine the effect of straw combined with different proportions (0, 5, 20, 40 t ha-1) of biochar on soil nitrogen retention, phosphorous availability, rice yield, and physiological parameters. Five treatments were included: control (CK), 7 t ha−1 straw + 0 t ha−1 biochar (ST), 7 t ha−1 straw + 5 t ha−1 biochar (SC1), 7 t ha−1 straw + 20 t ha−1 biochar (SC2), 7 t ha−1 straw + 40 t ha−1 biochar (SC3). The results indicated that the biochar had an encouraging effect on paddy fields with straw returning: (1) SC3 treatment significantly increased ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3−-N) content in soils compared to ST, increasing by 30.19% and 42.72%, while SC2 treatment increased by 25.84% and 30.40%, respectively; (2) Regarding soil phosphorus availability, ST treatment showed a negative effect, while proper biochar application rate (20 t ha−1) effectively increased Olsen-P content (18.24%); (3) No significant difference among these treatments was observed in the photosynthetic characteristics. Notably, 20 t ha−1 biochar application (SC2) effectively enhanced rice components (stem, ear) dry biomass, improved rice yield (10.14%), and Harvest index (HI: 4.99%). Hence, the appropriate rate (20 t ha−1) of biochar combined with straw (7 t ha−1) returning is a promising strategy for increasing nitrogen retention and phosphorous availability, alleviating N and P losses and promoting rice growth and yield. These findings are expected to provide a new perspective in that straw-returning with biochar achieves high efficiency, ecological, and sustainable development of agriculture.