Single atom Cu-N-C catalysts for the electro-reduction of CO_(2) to CO assessed by rotating ring-disc electrode

The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient CO_(2)RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for CO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly CO selective at low overpotentials(from -0.6 to -0.8 V vs.RHE) in 0.1 M KHCO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N_(4) moieties exhibits a CO_(2)-to-CO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/CO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from CO_(2)RR.

Adaptive multicascade attribute reduction based on quantum-inspired mixed co-evolution

Due to the fact that conventional heuristic attribute reduction algorithms are poor in running efficiency and difficult in accomplishing the co-evolutionary reduction mechanism in the decision table, an adaptive multicascade attribute reduction algorithm based on quantum-inspired mixed co-evolution is proposed. First, a novel and efficient self- adaptive quantum rotation angle strategy is designed to direct the participating populations to mutual adaptive evolution and to accelerate convergence speed. Then, a multicascade model of cooperative and competitive mixed co-evolution is adopted to decompose the evolutionary attribute species into subpopulations according to their historical performance records, which can increase the diversity of subpopulations and select some elitist individuals so as to strengthen the sharing ability of their searching experience. So the global optimization reduction set can be obtained quickly. The experimental results show that, compared with the existing algorithms, the proposed algorithm can achieve a higher performance for attribute reduction, and it can be considered as a more competitive heuristic algorithm on the efficiency and accuracy of minimum attribute reduction.

Enhanced minimum attribute reduction based on quantum-inspired shuffled frog leaping algorithm

Attribute reduction in the rough set theory is an important feature selection method, but finding a minimum attribute reduction has been proven to be a non-deterministic polynomial （NP）-hard problem. Therefore, it is necessary to investigate some fast and effective approximate algorithms. A novel and enhanced quantum-inspired shuffled frog leaping based minimum attribute reduction algorithm （QSFLAR） is proposed. Evolutionary frogs are represented by multi-state quantum bits, and both quantum rotation gate and quantum mutation operators are used to exploit the mechanisms of frog population diversity and convergence to the global optimum. The decomposed attribute subsets are co-evolved by the elitist frogs with a quantum-inspired shuffled frog leaping algorithm. The experimental results validate the better feasibility and effectiveness of QSFLAR, comparing with some representa- tive algorithms. Therefore, QSFLAR can be considered as a more competitive algorithm on the efficiency and accuracy for minimum attribute reduction.

Reduction in nerve root compression by the nucleus pulposus after Feng's Spinal Manipulation

Ninety-four patients with lumbar intervertebral disc herniation were enrolled in this study. Of these, 48 were treated with Feng＇s Spinal Manipulation, hot fomentation, and bed rest （treatment group）. The remaining 46 patients were treated with hot fomentation and bed rest only （control group）. After 3 weeks of treatment, clinical parameters including the angle of straight-leg raising, visual analogue scale pain score, and Japanese Orthopaedic Association score for low back pain were improved. The treatment group had significantly better improvement in scores than the control group. Magnetic resonance myelography three-dimensional reconstruction imaging of the vertebral canal demonstrated that filling of the compressed nerve root sleeve with cerebrospinal fluid increased significantly in the treatment group. The diameter of the nerve root sleeve was significantly larger in the treatment group than in the control group. However, the sagittal diameter index of the herniated nucleus pulposus and the angle between the nerve root sleeve and the thecal sac did not change significantly in either the treatment or control groups. The effectiveness of Feng＇s Spinal Manipulation for the treatment of symptoms associated with lumbar intervertebral disc herniation may be attributable to the relief of nerve root compression, without affecting the herniated nucleus pulposus or changing the morphology or position of the nerve root.

Study on Kinetics of Cathodic Reduction of Dissolved Oxygen in 3.5% Sodium Chloride Solution

Electrochemical reduction of dissolved oxygen in seawater on metals is of great importance for corrosion studies. The present paper studied cathodic reduction of dissolved oxygen on Q235 carbon steel in 3.5% sodium chloride （NaCl） solutions by cyclic voltammetry （CV）, electrochemical impedance spectroscopy （EIS）, rotating disk electrode （RDE） and rotating ring-disk electrode （RRDE）. The cyclic voltammetric results demonstrated the cathodic process on Q235 carbon steel in O2-saturated 3.5% NaCl solution contains three reactions： dissolved oxygen reduction, iron oxides reduction and hydrogen evolution. The peak potential of oxygen reduction reaction （ORR） is - 0.85 V vs Ag/AgCl, 3 molL^-1 KCI. The EIS results indicated that the ORR occurring on Q235 carbon steel is a 4-electron process and that no finite diffusion is caused by the intermediate of H2O2 produced by ORR. The RDE and RRDE voltammograms confirmed the EIS results and it was found that the number of transferred electrons for ORR was nearly 4, i.e., dissolved oxygen reduced to water.

A Study of Solar Rotation and Differential Rotation

The Sun has solar rotation;nevertheless, many evidences have suggested that different latitude of the Sun rotates in different speed, which is now known as differential rotation. This work calculates the solar rotation speeds near the equator and 30? in the northern hemisphere using Fixed-Point Arithmetic method. The calculated results show a greater speed at the equator than the speed at 30?, indicating that the speed decreases as the latitude becomes higher. .

Aliasing-free high resolution imaging of fast rotating targets with narrowband radar

Narrowband radar has been successfully used for high resolution imaging of fast rotating targets by exploiting their micro-motion features.In some practical situations,however,the target image may suffer from aliasing due to the fixed pulse repetition interval(PRI)of traditional radar scheme.In this work,the random PRI signal associated with compressed sensing(CS)theory was introduced for aliasing reduction to obtain high resolution images of fast rotating targets.To circumvent the large-scale dictionary and high computational complexity problem arising from direct application of CS theory,the low resolution image was firstly generated by applying a modified generalized Radon transform on the time-frequency domain,and then the dictionary was scaled down by random undersampling as well as the atoms extraction according to those strong scattering areas of the low resolution image.The scale-down-dictionary CS(SDD-CS)processing scheme was detailed and simulation results show that the SDD-CS scheme for narrowband radar can achieve preferable images with no aliasing as well as acceptable computational cost.

Noise reduction and signal to noise ratio improvement in magneto-optical polarization rotation measurement

The measurement of an extremely small magneto-optical polarization rotation angle with high sensitivity is integral to many scientific and technological applications. In this Letter, we have presented a technique based on Faraday modulation combined with the optical differential method to measure an extremely small polari- zation rotation angle with high sensitivity. The theoretical and experimental results show that common mode noise is reduced appreciably and signal to noise ratio is enhanced. The effectiveness of this technique has been demonstrated by measuring the Verdet constant of terbium gallium garnet glass and measuring the small polari- zation rotation angle. A sensitivity of enhancement of one order of magnitude has been achieved using differ- ential detection based on Faraday modulation.

A Fixed-Point Iterative Method for Discrete Tomography Reconstruction Based on Intelligent Optimization

Discrete Tomography(DT)is a technology that uses image projection to reconstruct images.Its reconstruction problem,especially the binary image(0–1matrix)has attracted strong attention.In this study,a fixed point iterative method of integer programming based on intelligent optimization is proposed to optimize the reconstructedmodel.The solution process can be divided into two procedures.First,the DT problem is reformulated into a polyhedron judgment problembased on lattice basis reduction.Second,the fixed-point iterativemethod of Dang and Ye is used to judge whether an integer point exists in the polyhedron of the previous program.All the programs involved in this study are written in MATLAB.The final experimental data show that this method is obviously better than the branch and bound method in terms of computational efficiency,especially in the case of high dimension.The branch and bound method requires more branch operations and takes a long time.It also needs to store a large number of leaf node boundaries and the corresponding consumptionmatrix,which occupies a largememory space.

减氮对麦玉轮作农田土壤反硝化细菌群落结构和多样性的影响

探究减氮对华北地区麦玉轮作农田土壤反硝化细菌群落结构和多样性影响,为华北地区麦玉轮作农田氮肥管理提供技术支持,本研究以不施氮为对照(CK),设置2个施氮量,分别为常规施氮量(纯氮300 kg·hm^(-2),N2)、减氮20%(纯氮240 kg·hm^(-2),N1),提取土壤DNA,用nirS(细胞色素cd1-亚硝酸还原酶)、nirK(Cu-亚硝酸还原酶)引物扩增后采用MiSeq PE300测序技术,研究施氮量对麦玉轮作农田土壤性状及nirS、nirK反硝化细菌群落结构及多样性的影响。结果表明,3个处理nirS、nirK反硝化细菌α-多样性指数无显著差异,nirS反硝化细菌α-多样性高于nirK。减氮显著影响nirS、nirK反硝化细菌物种组成。减氮对nirS、nirK反硝化细菌门水平及nirK纲水平物种组成无显著影响,但显著降低了nirS反硝化细菌Deltaproteobacteria(δ-变形菌纲)相对丰度;减氮显著影响nirS、nirK属水平物种组成。硝态氮、速效磷、pH值是影响土壤nirS反硝化细菌属水平群落结构主要环境因子;pH值是影响土壤nirK反硝化细菌属水平群落结构的主要环境因子。研究表明,适量减氮不影响反硝化细菌α-多样性,但显著影响反硝化细菌属水平群落组成和群落结构,减氮主要是通过影响土壤性状及微生物群落结构进而影响农田土壤N2O排放。

减氮对华北地区麦玉轮作农田土壤N2O排放调控机理

【目的】探究减氮对华北地区麦玉轮作农田土壤N2O排放调控机制。【方法】冬小麦季和夏玉米季均以不施氮为对照(CK),设置2个施氮量,分别为常规施氮量(纯氮300 kg/hm2,N2)、减氮20%(纯氮240 kg/hm2,N1),研究施氮量对麦玉轮作农田土壤性质及N2O排放通量影响,基于逐步回归分析,研究减氮对麦玉轮作农田土壤N2O排放调控机制。【结果】(1)减氮有效降低了N2O排放通量,且夏玉米季N2O排放通量远高于冬小麦季,夏玉米季由施肥引起的N2O排放量较高。(2)冬小麦季N2O排放通量与环境因子逐步回归公式为:N2O排放通量=181.952+1.450×硝态氮+8.401×铵态氮-0.514×电导率;硝态氮、铵态氮会对冬小麦季N2O排放通量产生显著的正向影响,而电导率会对冬小麦季N2O排放通量产生显著的负向影响。(3)夏玉米季N2O排放通量与环境因子逐步回归公式为:N2O排放通量=-354.606+4.592×硝态氮+157.848×铵态氮;硝态氮、铵态氮会对夏玉米季N2O排放通量产生显著的正向影响。【结论】综上可知,适量减氮显著降低夏玉米季N2O累积排放量和增温潜势,应加强夏玉米季农田水肥管理。

对转螺旋桨气动噪声试验系统设计与试验研究

风洞内对转螺旋桨气动噪声试验存在时间协调难、成本高的问题,依托地面声学环境,研制能够模拟对转螺旋桨地面开车状态的对转螺旋桨气动噪声试验系统。对某穿孔结构的对转螺旋桨和基准桨开展气动噪声试验,对设计的试验系统进行验证,并对穿孔结构对转螺旋桨的降噪效果进行评估。结果表明:在所测试的工况范围内,穿孔结构对转螺旋桨在保证气动性能的前提下能够有效降低噪声;在对飞机舱内影响最显著的90°指向角处,二阶通过频率处降噪量达到5 dB。本文设计的气动噪声试验系统,能够为对转螺旋桨气动噪声评估和降噪设计提供帮助。

硬膜外阻滞复合脊柱定点旋转复位法治疗急性腰椎间盘突出症的效果

目的观察硬膜外阻滞复合脊柱定点旋转复位法治疗急性腰椎间盘突出症的临床效果。方法选取2021年5月至2023年5月河南科技大学第一附属医院开元院区疼痛科收治的急性腰椎间盘突出症患者90例,以随机数字表法分成试验组、手法复位组和硬膜外阻滞组,每组30例。试验组在行硬膜外阻滞的基础上联合脊柱定点旋转复位法,手法复位组仅接受脊柱定点旋转复位手法,硬膜外阻滞组仅接受硬膜外阻滞。记录3组患者治疗前后疼痛视觉模拟评分(VAS),采用日本骨科协会(JOA)评分评价其治疗结束后腰部疼痛及腰椎功能改善情况。结果3组患者经治疗后VAS评分均降低,且试验组VAS评分低于手法复位组和硬膜外阻滞组(P<0.05)。3组患者经治疗后JOA评分均提高,且试验组JOA评分高于手法复位组和硬膜外硬膜外阻滞组(P<0.05)。结论硬膜外阻滞复合脊柱定点旋转复位法可有效缓解急性腰椎间盘突出症患者的疼痛,提高其JOA评分。

补阳还五汤联合脊柱定点旋转复位手法干预颈型颈椎病的临床研究

目的 探讨补阳还五汤联合脊柱定点旋转复位手法对颈型颈椎病患者颈椎生理曲度及炎症因子水平的影响。方法 选取2021年2月-2023年2月收治的100例颈型颈椎病患者,随机分成2组。对照组采用牵引方法治疗,观察组在对照组治疗基础上联合补阳还五汤联合脊柱定点旋转复位手法治疗,均连续治疗4周。观察2组患者治疗前后中医证候积分、颈椎功能障碍(NDI)评分、视觉模拟(VAS)评分、颈椎生理曲度、颈椎各方向ROM、炎性因子指标改善情况,比较2组总有效率和治疗安全性。结果 治疗后,2组各项中医证候积分、NDI评分、VAS评分、各项炎性因子指标均降低,且观察组较对照组低(P<0.05);2组颈椎生理曲度及颈椎各方向ROM均升高,且观察组较对照组高(P<0.05);观察组总有效率(92.0%)高于对照组(76.0%)(P<0.05);2组均未发生治疗相关不良反应。结论 补阳还五汤联合脊柱定点旋转复位手法能够缓解颈型颈椎病临床症状,抑制患者体内炎症反应,改善颈椎生理曲度,提高颈椎活动功能,疗效明确,安全性良好。

颈椎矢状位端提手法对椎间盘及小关节影响的有限元分析

背景:在颈椎病的致病因素中,椎间盘突出、小关节错位和椎间孔狭窄是导致患者出现症状的重要因素,而不适当的手法复位可能会加重颈椎间盘破裂的可能性,导致患者症状加重。目的:通过有限元分析比较传统颈椎旋转复位手法与颈椎矢状位端提手法对施术节段椎间盘、小关节和椎间孔面积的影响。方法:选取1名颈部正常男性志愿者的颈部CT资料,将CT数据导入Mimics 17.0三维重建软件,依次使用Geo-magic Studio 12.0、Solidworks2017和Ansys Workbench 17.0软件构建椎间盘、关节软骨等C_(3-6)颈椎有限元模型;固定C_(5)椎体下终板,在上位椎体(C_3)的上表面施加均匀分布、垂直向下的50 N载荷,比较实施传统颈椎旋转复位手法与颈椎矢状位端提手法和整复时,C_(4)-C_(5)节段椎间盘应力、形变大小及方向、关节囊应力、小关节位移及双侧椎间孔面积的变化。结果与结论:(1)实施旋转复位手法时,C_(4-5)椎间盘的最大范式等效应力为8.06 MPa、总形变为1.05 mm,纤维环向左前外膨出;实施矢状位端提手法时,C_(4-5)椎间盘的最大范式等效应力为2.60 MPa、总形变为0.90 mm,纤维环向左后方膨出;相比于旋转复位手法,矢状位端提手法在施术时对椎间盘的压力较小(约为颈椎旋转手法的32.3%)、椎间盘形变程度也轻(约为旋转手法的85.7%);(2)实施旋转复位手法时,左侧和右侧关节囊韧带最大应力分别为0.37 MPa和1.69 MPa,小关节的总体位移为2.21 mm,右侧椎间孔面积减小约3.8%,左侧椎间孔面积增大约0.9%;实施矢状位端提手法时,左侧和右侧关节囊韧带最大应力分别为0.27 MPa和1.70 MPa,小关节的总体位移为1.63 mm,右侧椎间孔面积增大约2.6%,左侧椎间孔面积减小约0.9%;与旋转复位手法相比,矢状位端提手法对小关节的位移、关节囊应力和椎间孔面积改变较小,操作时较为安全;(3)结果提示,与颈椎旋转复位手法相比,矢状位端提手法对小关节位移、椎间盘应力/形变程度、关节囊应力和椎间孔面积的改变较小,临床中在准确评估患者病情后应结合生物力学结果选择更为合适的手法。

顺势法对伴有肱骨大结节骨折的急性肩关节前脱位复位的效果

目的:比较顺势法与手牵足蹬法治疗急性肩关节前脱位伴肱骨大结节骨折的临床效果。方法:回顾性分析2022年6月~2024年6月在四川省骨科医院就诊的急诊肩关节前脱位伴肱骨大结节患者60例。采用随机数字表法分为观察组(采用顺势法)和对照组(采用手牵足蹬法)两组。观察两组患者临床疗效,比较两组患者复位前一般资料、复位操作时间、复位时疼痛评分、一次复位成功率、肩关节UCLA评分、复位后并发症发生情况。结果:与对照组相比,观察组复位操作时间更短(P<0.05)、复位疼痛评分更低(P<0.05)、一次复位成功率更高(P<0.05),差异均具有统计学意义。随访3个月时,两组患者的肩关节UCLA评分差异无统计学意义(P>0.05)。观察组的并发症发生率低于对照组(P<0.05),且总有效率高于对照组(P<0.05),差异均具统计学意义。结论:顺势法具有复位操作时间短、一次复位成功率高、复位过程患者痛苦小、复位后功能恢复较好、总有效性与安全性高等优点,是一种安全、高效的复位方法,值得在临床实践中推荐。

不同稻虾模式对硫酸盐还原菌群落结构及多样性的影响

硫酸盐还原菌(SRB)作为一种土壤中普遍存在的微生物,在生物地球化学循环中发挥关键作用。本研究以常规水稻单作模式为对照(CK),无环沟式稻虾(水稻和克氏原螯虾)共作模式(RS_(0))、有环沟式稻虾轮作模式(RS_(1))与有环沟式稻虾共作模式(RS_(2))为研究对象,采用16S rDNA高通量测序技术,探究不同稻虾模式对土壤硫酸盐还原菌(SRB)群落结构及多样性的影响。结果表明:与CK相比,3种稻虾模式均显著降低了水稻成熟期土壤氧化还原电位(Eh)和硫化物、硫酸盐、全硫含量,提高了pH和有机质、速效钾、碱解氮含量,其中RS_(0)提升效果最为显著;3种稻虾模式SRB群落结构存在差异:RS1、RS2和RS0处理的δ-变形菌纲相对丰度比CK分别下降46.00%、63.61%和51.94%,而α-变形菌纲则分别提高402.52%、441.01%和584.17%。3种稻虾模式硫酸盐还原菌Observed_species指数、Shannon指数和Simpson指数与CK相比均显著提高,但不同稻虾模式间丰富度及多样性没有显著差异。RDA分析表明,速效钾、Eh、有机质、有效磷、碱解氮、硫酸盐、硫化物、全硫和pH是影响稻田土壤SRB群落结构的影响因子,其中全硫和硫化物是主要因子。综上,稻虾模式能维持或者提高稻田土壤养分状况和SRB群落丰富度及多样性,改善稻田土壤SRB群落结构,结果可为稻虾种养土壤生态健康及稻田综合种养土壤微生物研究提供参考和支撑。

外展外旋复位法治疗肩关节脱位的临床效果分析

目的分析外展外旋复位法治疗肩关节脱位的临床效果。方法回顾性选取2022年1月—2023年9月潍坊市益都中心医院收治的60例肩关节脱位患者,根据治疗方式将患者分为两组,各30例。观察组实行外展外旋复位法,对照组采取足蹬法。比较两组患者复位成功率、肩关节功能、并发症发生情况、疼痛程度及复位时间。结果观察组复位成功率(100.00%)明显高于对照组(76.67%),差异有统计学意义(χ^(2)=7.925,P<0.05)。治疗后,观察组疼痛程度评分、出院1个月后肩关节功能评分以及并发症发生率均明显低于对照组,复位时间短于对照组,差异有统计学意义(P均<0.05)。结论外展外旋复位法治疗肩关节脱位有很好的疗效。

螺旋桨穿孔结构声学软叶片设计与试验研究

对转螺旋桨气动噪声的产生机理十分复杂,而且螺旋桨飞机并无短舱声衬等被动降噪部件可以在传播过程中吸收噪声,螺旋桨噪声会直接辐射向机身和周围环境,噪声问题突出,降低螺旋桨噪声源强度是研制低噪声螺旋桨飞机的关键。采用CFD和远场噪声评估相结合的方法,通过在螺旋叶尖吸力面前缘布置“小孔+贯穿通道”结构,构成“软叶片”模块,以平衡叶片前缘处的压力峰值,降低螺旋桨产生的载荷噪声;根据设计结果加工制造出常规桨和软叶片螺旋桨,依托对转螺旋桨气动噪声试验系统开展气动噪声试验。结果表明:在所测试的工况范围内,穿孔结构对转螺旋桨可以在保证气动性能的前提下有效降低噪声,在对飞机舱内影响最显著的90°指向角处,二阶通过频率处降噪量达5 dB。

不同水旱轮作模式下秸秆还田与精量减氮对水稻产量、氮素吸收利用及土壤氮含量的影响

【目的】水旱轮作模式不仅影响土壤氮素残留率,而且旱作季秸秆还田后带入土壤的氮量也不同,导致对后茬水稻的氮素供应也不同。研究考虑秸秆氮素条件下的精准减氮量,以充分发挥秸秆氮素和轮作模式优势。【方法】以四川地区主推品种‘F优498’为材料,在四川农业大学现代化农业科研园区进行大田裂区试验,以3种水旱轮作模式下的秸秆还田为主区:油菜–水稻轮作(RR)、小麦–水稻轮作(WR)、青菜–水稻轮作(CR);以3个施氮量为裂区:不施氮(N_0)、传统施氮量(N_(1))、精量减氮(N_(2))。根据计算,RR、CR和WR轮作模式下N_(2)处理的施氮量分别为120、145和140 kg/hm^(2),分别较N1处理(150 kg/hm^(2))减少氮肥用量20.00%、3.33%和6.67%。于水稻拔节期、齐穗期、成熟期取植株样分析干物质积累和氮素吸收量,成熟期测定水稻产量和产量构成因素。旱季作物和水稻收获后取0—20 cm土壤样品,测定全氮及碱解氮含量。【结果】与CR和WR处理相比,RR平均水稻产量2018年分别增加3.85%和13.06%,2019年分别增加14.01%和2.57%,主要原因是其能保证较高的有效穗数和千粒重,促进籽粒灌浆结实;2018年干物质积累总量平均分别增加1.84%和23.50%,2019年分别增加12.87%和4.19%;2018年氮素积累总量平均分别增加17.29%和14.59%,2019年分别增加10.50%和5.00%;2018年氮肥偏生产力分别增加11.43%和17.08%,2019年分别增加25.57%和11.42%。2018、2019年RR处理稻田土壤全氮含量分别较CR和WR处理增加16.67%和9.25%、14.69%和2.01%,碱解氮含量分别增加了13.90%和9.80%、17.76%和8.48%。同一轮作模式秸秆还田下,N_(2)处理的水稻产量、干物质积累、氮素吸收及土壤氮素含量与N_(1)处理多无显著差异,但氮肥偏生产力、氮肥生理利用率多表现为N_(2)>N_(1),其中2018年N2处理在RR模式下的氮肥偏生产力较N1处理显著增加23.50%,2019年显著增加20.89%。RR、WR和CR模式综合评价表明,水稻生产力综合排序为RR>CR>WR,得分最高的处理是RR+N_(1),其次是RR+N_(2)。【结论】油菜–水稻轮作模式秸秆还田优化了水稻各生育时期的干物质和氮素积累,促进了氮素利用和土壤培肥,从而增加水稻产量,配合精量减氮处理不影响水稻正常生长,但能减少20%氮肥使用,有助于秸秆高效利用和水稻节肥稳产。