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During the harvesting of cut-stem vegetables, the structural parameters of cutters have an important influence on the harvesting effect. Structural parameters of stalks directly affect the cutting effect of the cutter. The thickness of the stalk xylem has a strong influence on the cutting stability and cutting surface effect of the cutter. In this paper, the effect of the broccoli stalk xylem on conventional toothless cutters was investigated using broccoli stalks as the cutting object. It was found that a thicker xylem leads to shear force fluctuations, which in turn affects the smooth operation of the cutting device. Taking locust mouthparts as the research object, a bionic multi-tooth cutting method is proposed in this paper to obtain the contour curve based on the locust upper jaw cutting tooth lobe. By establishing the regression equation, the contour curve of the cutting teeth is fitted accurately. The cutter edge is designed with the locust’s maxillary incisive lobe as the bionic object. ANSYS software was used to simulate the cutting of a double disc cutter and broccoli stalk. The effect of each factor was analyzed by response-surface regression to determine the optimal cutter speed, machine forward speed, cutting inclination, blade overlap, and optimal cutting position. The cutting test is verified via broccoli stalks and a cutting test bench to further determine the cutting device operating parameters. The optimal operating parameters of the cutting device were 0.239 m/s forward speed, 30.974-degree cutting edge angle, 10.066 mm blade overlap, and 467.511 rpm.

ABSTRACT In view of the fact that the design of the cab structure of wheeled combine harvesters in China lacks ergonomic design parameters exclusive for Chinese drivers, there are generally problems such as high vibration and poor comfort of the whole machine structure during the harvesting process. Firstly, this paper designed the cab structure of a wheeled grain combine harvester based on ergonomics. Then, the driver's handling comfort and visibility were simulated and analyzed using Creo. Finally, the relevant dimensions of the driver's control device were optimized. The results show that the wheeled grain combine harvester cab based on ergonomic design better meets their driving comfort needs. In addition, it is found that the operating frequencies of the key components, such as the main shaft of the conveyor spindle, the vibrating screen, the threshing drum, and the intermediate shaft of the engine, partially overlap with the frequency of human discomfort. Therefore, modal planning is also needed for this harvester to meet human comfort requirements better. This paper provides the basic parameters for the design of the cab structure of the combine harvester with high comfort for the Chinese harvesting machinery driver.

After tertiary recovery from the oilfields, improving the production of the remaining hydrocarbon is always challenging. To significantly improve oil recovery, a heterogeneous composite flooding system has been developed with preformed particle gels (PPG) and polymers according to the technical approach of plugging and flooding combination. In addition, an oil saturation monitoring device and a large-scale 3D physical model were designed to better evaluate the performance of the technique. The evaluation results show that the viscosity, stability, and elasticity of the heterogeneous composite flooding system are better than the single polymer system. In addition, both systems exhibit pseudoplastic fluid characteristics and follow the principle of shear thinning. The results of seepage experiments showed that PPG migrates alternately in porous media in the manner of “piling plugging-pressure increasing-deformation migration”. The heterogeneous composite system can migrate to the depths of the oil layer, which improves the injection profile. In the visualization experiment, the heterogeneous composite system preferentially flowed into the high-permeability layer, which increased the seepage resistance and forced the subsequent fluid to flow into the medium and low permeability layers. The average saturation of the high, medium, and low permeability layers decreased by 4.74%, 9.51%, and 17.12%, respectively, and the recovery factor was further improved by 13.56% after the polymer flooding.

As a multi-source vibration machine, the complex vibration of the combine harvester has caused many effects on various components. In this paper, the dynamic response of the plate and shell on the combine harvester is studied, and the influence of various factors on the vibration of the plate and shell is determined. The structure of the plate and shell is optimized, and the scheme of structural optimization that replaces the finite element model with the surrogate model is developed. The structure is designed with Latin hypercube design (LHD), the model of response surface is generated based on the Kriging model, and then the parameters are optimized by a multi-objective genetic algorithm (MOGA). It is realized that the first-order natural frequency of the plate is increased by 14.6% under the same mass, avoiding the resonance range of the main excitation of the machine. At the same time, its dynamic response under the multi-point force is also greatly decreased by 62.4%.

顾心阳 金威 【摘要】 乌克兰危机短期内对中国拓展在海外的利益是不利的。中国在乌克兰拥有广泛的利益，但这些利益正在或即将因乌克兰危机受到影响。对于中国在乌克兰的利益，本次危机主要带来了负面影响。而对于中国在其他国家的利益，本次危机不光带来了消极影响，也有着积极影响。乌克兰危机仍在进行中，短期内似乎无法解决，如何衡量利弊得失，需要时间来证明。而中国如何利用这次危机达到获益最大、损失最小，实现利益的最大化，需要决策者的智慧。此次乌克兰危机对中国在海外谋求自身利益的影响也促使我们思考今后应该如何应对类似事件、保护在海外的利益。政党轮替、党派冲突是造成乌克兰等国动荡的主要因素，这提醒我们今后在这些国家拓展利益需要谨慎，如果一定要在这些国家拓展利益，不但需要与现任执政者搞好关系，同时也需要与反对派搞好关系。 The Ukrainian crisis is harmful to China’s overseas interests from a short term perspective. A wide range of Chinese interests in Ukraine are facing challenges due to the Ukrainian crisis. The impact of the Ukrainian crisis on China’s interests in Ukraine is mainly negative whereas the impact on China’s interests in other foreign countries is both negative and positive. The Ukrainian crisis is still in progress, and it does not seem to be reaching a resolution in the near future. Only time will tell what the ultimate impact will be. How China utilizes the crisis to maximize its gains and minimize its losses will test the wisdom of decision makers. The Ukrainian crisis’s impact on China’s overseas interests prompts us to consider how to deal with similar events and protect overseas interests. Rotation of ruling parties and the partisan conflicts are the major factors of turmoil occurring in Ukraine and other countries which reminds us that an expansion of interests in these countries needs to be prudent in the future. If China has to do so, it is necessary to build good relationships both with the ruling party and the opposition.

High stress is the main reason for high frequency of rock burst in deep coal mines. Backfilling mining serves as an effective method to control roof strata movement, alleviate the degree of stress concentration, and reduce the failure of surrounding rock and the risk of rock burst. To evaluate the controlling ability of the backfilling on mining stress in the gob area, the 1123 longwall panel of the Gucheng mine is taken as the project background. Theoretical analysis, laboratory test and field measurement are used to study the mining-induced stress distribution in the backfilling longwall face, and to reveal the feedback mechanism between the front abutment stress and bearing capacity of the backfilling body, helping to determine the backfilling rate of coal burst mine. The results show that the backfilling ratio in the early stage is lower than 80%, the subsidence of hard roof is serious, the influence area of front abutment stress is more than 30 m, and the degree of stress concentration reaches 1.5. The influence area and concentration degree of mining-induced stress in the fault affected area increase to 60 m and 1.65, respectively. Surrounding rock instability phenomenon, such as rib spalling and roof fall, happens frequently. The whole dynamic evolution characteristics of bearing stress in the backfilling body is measured. The stress distribution curve is divided into five stages, namely rapid decrease, transient stabilization, rapid increase, slow decrease, and secondary stabilization. The stabilization values of the bearing stress in the upper, middle, and lower regions of the gob area under the condition of low backfilling ratio are 1.5, 5.2 and 2.5 MPa, respectively. The backfilling body in the gob area is divided into non-sufficiently compacted zones and sufficiently compacted zones, and the continuous subsidence model of the hard roof under the support of the backfilling body is constructed, and the “ʅ” type subsidence curve of the hard roof is obtained, and the range of the insufficiently compacted area decreases approximately linearly with the backfilling ratio. The test obtains the evolution curves of elastic modulus and uniaxial compressive strength of the back-filling body with time. By combining with the roof subsidence curve and face advance speed, the distribution curve of mining-induced stress in the whole area of the longwall face is obtained. Negative exponential relationship is established for the backfilling rate and the afront abutment stress, which reveals the reverse feedback mechanism between them. Quantitative assessment on the load reduction and burst prevention effect of backfilling mining is realized. The trinity enhancement measures for improving the backfilling ratio of the gob area are proposed, which raises the backfilling ratio of the 1123 working face to more than 90%. The bearing capacity of the backfilling body is strengthened. The trinity measures reduce the separation space under the hard roof to 50 mm. The stress concentration coefficient decreases to 1.3. Correspondingly, the controlling effect of the surrounding rock of the longwall panel is significantly improved.

Considering the phase behaviors in condensate gas reservoirs and the oil-gas two-phase linear flow and boundary-dominated flow in the reservoir, a method for predicting the relationship between oil saturation and pressure in the full-path of tight condensate gas well is proposed, and a model for predicting the transient production from tight condensate gas wells with multiphase flow is established. The research indicates that the relationship curve between condensate oil saturation and pressure is crucial for calculating the pseudo-pressure. In the early stage of production or in areas far from the wellbore with high reservoir pressure, the condensate oil saturation can be calculated using early-stage production dynamic data through material balance models. In the late stage of production or in areas close to the wellbore with low reservoir pressure, the condensate oil saturation can be calculated using the data of constant composition expansion test. In the middle stages of production or when reservoir pressure is at an intermediate level, the data obtained from the previous two stages can be interpolated to form a complete full-path relationship curve between oil saturation and pressure. Through simulation and field application, the new method is verified to be reliable and practical. It can be applied for prediction of middle-stage and late-stage production of tight condensate gas wells and assessment of single-well recoverable reserves.

IntroductionProliferative diabetic retinopathy (PDR) is a common diabetes complication, significantly impacting vision and quality of life. Previous studies have suggested a potential link between arginine pathway metabolites and diabetic retinopathy (DR). Connective tissue growth factor (CTGF) plays a role in the occurrence and development of fibrovascular proliferation (FVP) in PDR patients. However, the relationship between arginine pathway metabolites and FVP in PDR remains undefined. This study aimed to explore the correlation between four arginine pathway metabolites (arginine, asymmetric dimethylarginine[ADMA], ornithine, and citrulline) and the severity of FVP in PDR patients.MethodsIn this study, plasma and aqueous humor samples were respectively collected from 30 patients with age-related cataracts without diabetes mellitus (DM) and from 85 PDR patients. The PDR patients were categorized as mild-to-moderate or severe based on the severity of fundal FVP. The study used Kruskal-Wallis test to compare arginine, ADMA, ornithine, and citrulline levels across three groups. Binary logistic regression identified risk factors for severe PDR. Spearman correlation analysis assessed associations between plasma and aqueous humor metabolite levels, and between ADMA and CTGF levels in aqueous humor among PDR patients.ResultsADMA levels in the aqueous humor were significantly greater in patients with severe PDR than in those with mild-to-moderate PDR(P=0.0004). However, the plasma and aqueous humor levels of arginine, ornithine, and citrulline did not significantly differ between mild-to-moderate PDR patients and severe PDR patients (P>0.05). Binary logistic regression analysis indicated that the plasma (P=0.01) and aqueous humor (P=0.006) ADMA levels in PDR patients were risk factors for severe PDR. Furthermore, significant correlations were found between plasma and aqueous humor ADMA levels (r=0.263, P=0.015) and between aqueous humor ADMA and CTGF levels (r=0.837, P

Abstract Accurately identifies the cellular composition of complex tissues, which is critical for understanding disease pathogenesis, early diagnosis, and prevention. However, current methods for deconvoluting bulk RNA sequencing (RNA‐seq) typically rely on matched single‐cell RNA sequencing (scRNA‐seq) as a reference, which can be limiting due to differences in sequencing distribution and the potential for invalid information from single‐cell references. Hence, a novel computational method named SCROAM is introduced to address these challenges. SCROAM transforms scRNA‐seq and bulk RNA‐seq into a shared feature space, effectively eliminating distributional differences in the latent space. Subsequently, cell‐type‐specific expression matrices are generated from the scRNA‐seq data, facilitating the precise identification of cell types within bulk tissues. The performance of SCROAM is assessed through benchmarking against simulated and real datasets, demonstrating its accuracy and robustness. To further validate SCROAM's performance, single‐cell and bulk RNA‐seq experiments are conducted on mouse spinal cord tissue, with SCROAM applied to identify cell types in bulk tissue. Results indicate that SCROAM is a highly effective tool for identifying similar cell types. An integrated analysis of liver cancer and primary glioblastoma is then performed. Overall, this research offers a novel perspective for delivering precise insights into disease pathogenesis and potential therapeutic strategies.

Kinematic calibration plays a pivotal role in enhancing the absolute positioning accuracy of industrial robots, with parameter identification and error compensation constituting its core components. While the conventional parameter identification method, based on linearization, has shown promise, it suffers from the loss of high-order system information. To address this issue, we propose an unscented Kalman filter (UKF) with adaptive process noise covariance for robot kinematic parameter identification. The kinematic model of a typical 6-degree-of-freedom industrial robot is established. The UKF is introduced to identify the unknown constant parameters within this model. To mitigate the reliance of the UKF on the process noise covariance, an adaptive process noise covariance strategy is proposed to adjust and correct this covariance. The effectiveness of the proposed algorithm is then demonstrated through identification and error compensation experiments for the industrial robot. Results indicate its superior stability and accuracy across various initial conditions. Compared to the conventional UKF algorithm, the proposed approach enhances the robot’s accuracy stability by 25% under differing initial conditions. Moreover, compared to alternative methods such as the extended Kalman algorithm, particle swarm optimization algorithm, and grey wolf algorithm, the proposed approach yields average improvements of 4.13%, 26.47%, and 41.59%, respectively.

Abstract Offshore wind power, with accelerated declining levelized costs, is emerging as a critical building-block to fully decarbonize the world’s largest CO2 emitter, China. However, system integration barriers as well as system balancing costs have not been quantified yet. Here we develop a bottom-up model to test the grid accommodation capabilities and design the optimal investment plans for offshore wind power considering resource distributions, hourly power system simulations, and transmission/storage/hydrogen investments. Results indicate that grid integration barriers exist currently at the provincial level. For 2030, optimized offshore wind investment levels should be doubled compared with current government plans, and provincial allocations should be significantly improved considering both resource quality and grid conditions. For 2050, offshore wind capacity in China could reach as high as 1500 GW, prompting a paradigm shift in national transmission structure, favoring long-term storage in the energy portfolio, enabling green hydrogen production in coastal demand centers, resulting in the world’s largest wind power market.

China has proposed the ambitious target of peaking the carbon emissions by 2030 and realizing the carbon neutrality by 2060 (hereafter referred to as “double carbon” goal). Central China is supposed to be one of the most essential aspect for this target. However, renewable resources in the central China region encounter the issues of inferior capacity factor and restricted resource potential. A resource analysis for local onshore wind and solar PV is conducted here, incorporating inversion analysis data with high spatial and temporal resolutions (include wind field, surface radial, local elevation, slope and landscape), to propose the (1) spatial distribution and seasonal fluctuation of local onshore wind and solar PV; (2) supplied curves for all the provincial regions in Central China at every renewable investment level; (3) optimal provincial allocation and overall portfolio for local renewables in the Central China. This research is supposed to provide data and model support for the ongoing deployment of renewables in Central China, and the fulfillment of the “double carbon” goal in the entire country.

Diabetic microangiopathy is a typical and severe problem in diabetics, including diabetic retinopathy, diabetic nephropathy, diabetic neuropathy, and diabetic cardiomyopathy. Patients with type 2 diabetes and diabetic microvascular complications have significantly elevated levels of Asymmetric dimethylarginine (ADMA), which is an endogenous inhibitor of nitric oxide synthase (NOS). ADMA facilitates the occurrence and progression of microvascular complications in type 2 diabetes through its effects on endothelial cell function, oxidative stress damage, inflammation, and fibrosis. This paper reviews the association between ADMA and microvascular complications of diabetes and elucidates the underlying mechanisms by which ADMA contributes to these complications. It provides a new idea and method for the prevention and treatment of microvascular complications in type 2 diabetes.

To accurately classify the stability of surrounding rock masses, a novel method (VSV-BDA) based on virtual state variables (VSVs) and Bayesian discriminant analysis (BDA) is proposed. The factors influencing stability are mapped by an artificial neural network (ANN) capable of recognizing the model of rock mass classification, and the obtained output vector is treated as VSVs, which are verified as obeying a multinormal distribution with equal covariance matrixes by normal distribution testing and constructed statistics. The prediction variance ratio test method is introduced to determine the optimal dimension of the VSVs. The VSV-BDA model is constructed through the use of VSVs and the optimal dimension on the basis of the training samples, which are divided from the collected samples into three situations having different numbers. ANN and BDA models are also constructed based on the same training samples. The predictions by the three models for the testing samples are compared; the results show that the proposed VSV-BDA model has high prediction accuracy and can be applied in practical engineering.

An effective approach is proposed to adjust the surface morphology induced by using a femtosecond laser, including the area and period of rippled structures. The effect of the processing steps and laser polarization on the surface morphology of rippled structures on a titanium surface was experimentally investigated in this study. A processing sequence was designed for two series of femtosecond laser pulses that irradiate a titanium surface, for example, N = 50(0°) + 50(90°). The experimental results show that the area and period of rippled structures can be simultaneously adjusted by following a two-step method. Due to the enhancement of energy absorption and SP-laser coupling of the initial rippled structures, large area surface structures with small periods are fabricated using two series of femtosecond laser pulses with the same polarization direction. By changing the polarization direction of the two series of femtosecond laser pulses, the recording, erasing, and rewriting of subwavelength ripples is achieved. During the rewriting process, material removal and the formation of new ripples simultaneously occur.