Nonlinear Shock Effect of China’s Fiscal Policy on Total Factor Productivity-Based on the Dual Perspective of Aggregate and Structure

In different economic periods,if the government blindly adopts expansionary fiscal policy,it may not be able to effectively increase total factor productivity(TFP).Based on this,this paper constructs a factor augmented vector autoregressive model with time-varying parameters and stochastic volatility(SV-TVP-FAVAR),and explores the nonlinear shock effect of China’s fiscal policy on TFP from the dual perspective of aggregate and structure.The study finds that:(1)At the aggregate level,the increase in fiscal expenditure in each period has a signifi cant inhibitory effect on TFP,while the increase in fiscal revenue has a significant promotion effect on TFP;(2)At the structural level of expenditure,in the period of economic depression and high economic growth,the increase in investment expenditure,education expenditure,technology expenditure,and public service expenditure all have a strong incentive effect on TFP,but the increase in science and technology and education expenditure in the period of economic stability has not effectively improved TFP;(3)At the structural level of tax,the increase in commodity tax,including consumption tax,value-added tax,and tariff,and individual income tax will signifi cantly inhibit the increase in TFP,but the increase in corporate income tax can signifi cantly increase TFP.Therefore,under the new economic normal,policy makers should build a two-wheel driven fiscal policy of“aggregate regulation and structural optimization”to optimize the structure of fiscal expenditure and taxation,and promote high-quality economic development.

Shock effects and history of the Yanzhuang meteorite: a case different from L-chondrites

MANY ordinary chondrites contain the networks of black veins with the widths from

Influence of air pressure on mechanical effect of laser plasma shock wave

The influence of air pressure on mechanical effect of laser plasma shock wave in a vacuum chamber produced by a Nd：YAG laser has been studied. The laser pulses with pulse width of 10ns and pulse energy of about 320mJ at 1.06μm wavelength is focused on the aluminium target mounted on a ballistic pendulum, and the air pressure in the chamber changes from 2.8 × 10^ 3 to 1.01 × 10^5pa. The experimental results show that the impulse coupling coefficient changes as the air pressure and the distance of the target from focus change. The mechanical effects of the plasma shock wave on the target are analysed at different distances from focus and the air pressure.

High temperature effects in moving shock reflection with protruding Mach stem

The influence of high temperature effects on the protrusion of Mach stem in strong shock reflection over a wedge was numerically investigated. A two-dimensional inviscid solver applies finite volume method and unstructured quadrilateral grids were employed to simulate the flow. Theoretical analysis was also conducted to understand the phenomenon. Both numerical and theoretical results indicate a wall-jet penetrating forward is responsible for the occurrence of Mach stem protrusion. The protrusion degree seems to depend on the thermal energy buffer capacity of the testing gas. Approaches to increase the energy buffer capacity, such as vibrational relaxation, molecular dissociation, and increase of frozen heat caoacitv, all tend to escalate the orotrusion effect.

The Shock Effects of Orthopyroxene in the Heavily Shocked Meteorites

1 Introduction The information of the deformation and phase transformation of minerals under the impact of different intensities can be obtained from some meteorites. Therefore, meteorites are good samples for the study of shock effects of minerals in natural impact process. Orthopyroxene is a kind of main rock-forming mineral in chondrite. The study of

Effect of heat shock protein 70 on cerebral ischemia

OBJECTIVE： TO summarize the relationship between heat shock protein 70 （HSP70） and cerebra ischemia. DATA SOURCES： An online search of Medline database was undertaken to identify relevant articles published in English from January 1980 to December 2005 by using the keywords of ＂heat shock protein 70, ischemia＂. Meanwhile, Chinese relevant articles published from January 2000 to December 2005 were searched in China National Knowledge Infrastructure （CNKI） database and Chinese Journal of Clinical Rehabilitation with the keywords of ＂heat shock protein 70, cerebral ischemia＂ in Chinese. STUDY SELECTION ： More than 100 related articles were screened, and 29 references mainly about HSP70 and cerebral ischemia were selected, including basic and clinical researches. As to the articles with similar content, those published in the authoritative journals in recent 3 years were preferential. DATA EXTRACTION： A total of 29 articles were collected and classified according to the structure, function and clinical application of HSP70. Among them, 1 article is about the structure of HSP70, 27 about the relationship between HSP70 and cerebral ischemia, and 2 about the clinical application of HSP70. DATA SYNTHESIS： HSP70 is one of the most conservative proteins during biological evolution. Experiments in cerebral ischemia revealed that HSP70 expression was time-dependent, also correlated with the injured site and severity. The cerebral ischemia induced HSP70 gene expression in hippocampus of gerbil had protection to tolerance of fatal ischemic injury for neurons. The increase of HSP70 expression may be one of the endogenous protective mechanisms during cerebral ischemia, and can effectively alleviate cerebral ischemia. Thus HSP70 protein and HSP70 mRNA have been taken as important indexes extensively applied in the basic study of cerebral ischemia by some scholars abroad. CONCLUSION： HSP70 plays a protective role in cerebral ischemia, and a deeper research into the biological function of HSP70 will provide a new way for the therapy of cerebral ischemia.

Evidence of Shock Metamorphism Effects in Allochthonous Breccia Deposits from the Colonia Crater,Sao Paulo,Brazil

The 3.6 km-diameter Colonia impact crater, centred at 2352'03"S and 4642'27"W,?lies 40 km to the south-west of the S?o Paulo city. The structure was formed on the crystalline basement rocks and displays a bowl-shaped with steeper slope near the top that decreases gently toward the centre of the crater. Over recent years were drilled two boreholes inside the crater, which reached a maximum depth of 142 m and 197 m. Geological profile suggests four different lithological associations: 1) unshocked crystalline basement rocks (197 - 140 m);2) fractured/brecciated basement rocks (140 - 110 m);3) polymictic allochthonous breccia deposits (110 - 40 m);and 4) post-impact deposits (40 - 0 m). Petrographic characterisation of the polymictic allochthonous breccia reveals a series of distinctive shock-metamorphic features, including, among others, planar deformation features in quartz, feldspar and mica, ballen silica, granular texture in zircon and melt-bearing impact rocks. The occurrence of melt particles and very high-pressure phase transformation in suevite breccia suggest a shock pressure regime higher than 60 GPa.

Nonplanar Shock Excitations in a Four Component Degenerate Quantum Plasma:the Effects of Various Charge States of Heavy Ions

A theoretical study on the nonlinear propagation of nonplanar （cylindrical and spherical） electrostatic modified ion-acoustic （mIA） shock structures has been carried out in an unmagnetized, collisionless four component degenerate plasma system （containing degenerate electron fluids, inertial positively as well as negatively charged light ions, and positively charged static heavy ions）. This investigation is valid for both non-relativistic and ultra-relativistic limits. The modified Burgers （mB） equation has been derived by employing the reductive perturbation method, and used to numerically analyze the basic features of shock structures. It has been found that the effects of degenerate pressure and number density of electron and inertial positively as well as negatively charged light ion fluids, and various charging state of positively charged static heavy ions significantly modify the basic features of mIA shock structures. The implications of our results to dense plasmas in astrophysical compact objects （e.g., non-rotating white dwarfs, neutron stars, etc.） are briefly discussed.

Theoretical Calculation of Effect Range of Shock Wave of Blasting

Based on the theories of shock wave and energy,this paper inquires into the effect range of shock wave in rock blasting with cylindrical coupling charges, and a new method for calculating the effect range is developed. A calculation example sbows that the new method is reasonable.

基于BP神经网络的水中双爆源爆炸冲击波峰值压力预测模型研究

为了获得水中等质量两爆源同步爆炸时冲击波耦合中心的峰值压力计算模型,利用Autodyn计算得到不同药量和爆距下的峰值压力数据.一方面根据量纲分析确定的函数形式拟合数据从而获得峰值压力的计算公式;另一方面对药量、爆距及峰值压力三类数据进行对数变换和归一化,并将其分为训练集和测试集,然后将训练集代入BP神经网络进行训练,得到结构相对简单、均方误差最小的BP神经网络预测模型.结果表明:公式计算结果和BP神经网络模型计算得到的峰值压力与实际值吻合较好,公式计算值与实际值的平均相对误差为1.08%,BP神经网络预测值与实际值的平均相对误差为0.52%,与公式计算相比,BP神经网络能够以更少的数据样本容量实现更高的精度预测.

大体积混凝土板微振动控制能力的测试与分析

精密大科学设施具有十分严格的微振动控制要求。为研究某大型精密设施内大体积混凝土底板对微振动的控制效果并为类似项目建设提供参考,在该设施建设现场进行了冲击激励、跑车激励和环境激励下的测试。通过对实测速度时程数据的处理,得出测点1~100 Hz内1 s的位移有效值。分析结果表明,在环境激励下,该设施中试验大厅底板表面的微振动水平能够达到控制要求;在冲击激励下,试验大厅底板表面微振动信号主要分布在5~30 Hz的频带内;场地内的车辆开动会对场地的微振动水平产生明显的影响;环境激励下,整个建设场地的微振动水平基本一致。研究结果对该精密大科学装置及类似工程的防微振设计具有重要的理论及参考价值。

能谱CT结石成分分析在泌尿系结石体外冲击波碎石中的应用

目的:探讨能谱CT结石成分分析在泌尿系结石体外冲击波碎石(ESWL)中的应用效果。方法:选取2022年5月—2023年8月惠州市中心人民医院门诊治疗的160例泌尿系结石患者,按照随机数表法将其分为两组,各80例。两组均接受ESWL治疗,在此之前,对照组采用常规CT平扫进行结石密度计算,试验组采用能谱CT进行结石成分评估。比较两组手术相关情况、结石清除率及并发症发生率。结果:试验组一次碎石成功率高于对照组,平均体外冲击波次数、最高工作电压平均值低于对照组,平均碎石时间短于对照组,差异有统计学意义(P<0.05)。试验组结石清除率为95.00%,高于对照组的83.75%,差异有统计学意义(P<0.05)。试验组>24 h肉眼血尿发生率均低于对照组,差异有统计学意义(P<0.05);但两组其余并发症发生率比较,差异无统计学意义(P>0.05)。结论:在泌尿系结石ESWL中应用能谱CT结石成分分析能为手术创造有利条件,确保一次碎石成功,提高术后结石清除率,并减少平均体外冲击波次数,缩短手术时间,降低>24 h肉眼血尿发生率。

Effects of heat shock protein-antigen peptide complexes (HACs) in melanoma B16 cell line on transplanted tumor development in mice

目的 :建立黑色素瘤 B16细胞热休克蛋白 -抗原肽复合物 (HACs)的制备方法并测其抑瘤效应。方法 :应用 Sephacryl S- 2 0 0凝胶过滤制备 HAC粗提物 ,应用 SDS- PAGE纯化 HACs,并测其抑瘤效应。结果 :应用 SDS- PAGE纯化的 HAC6 0、 HAC75和 HAC97不同程度地降低肿瘤发生率 ,延迟肿瘤发生时间和减慢肿瘤生长速度。结论 :6 0 0 0 0～ 970 0 0

密闭建筑温压炸药内爆炸后燃效应

温压炸药爆炸具有显著的后燃效应,在密闭空间内爆炸呈现多重毁伤效应,但后燃效应引起的多毁伤元耦合效应,以及后燃增强效应的量化分析尚不明确。基于搭建的大尺寸密闭建筑,开展不同药量下温压炸药及LiF替代铝粉炸药的内爆试验研究,对温度、冲击波超压、准静态压力及氧浓度进行测试,分析内爆条件下不同毁伤元的时空变化特征,结合LiF替代铝粉炸药爆炸的对比试验,阐明了密闭建筑内爆炸毁伤元的分布特点以及铝粉后燃效应对温度、冲击波超压、准静态压力和氧浓度变化的影响规律。研究结果表明:密闭空间内爆下热效应和压力效应在角落边界处得到显著增强,其中全过程比冲量在边界处增强了2.2~2.5倍;铝粉后燃反应可显著增强温度、冲击波超压、准静态压力和氧气消耗量,当药量达到300 g下,铝粉后燃烧导致爆炸冲击波超压峰值提高1.2倍,温度峰值提高6.4倍,准静态压力提高2.2倍,氧浓度消耗提高2.8倍。

商业银行数字化转型如何影响风险承担——基于负债成本与信贷选择机制的分析

对于商业银行数字化转型如何影响其风险承担水平的研究,既有文献多从数字化场景下的信贷市场技术变化与授信模式调整切入,忽视了银行融资市场的影响。区别于此,本文通过商业银行的城市聚类,使用地区数字普惠金融指数作为地区性商业银行数字化转型程度的代理变量,利用城市商业银行2012—2022年面板数据,从“融”与“贷”两个维度分析商业银行数字化转型对风险承担的影响及其作用机制。实证结论表明:商业银行数字化转型显著增加了商业银行风险承担水平,且表现为信用风险(信贷不良率)与经营稳定性风险(收入波动性)的共同上升。机制分析表明,数字化转型的风险积累通过成本冲击效应而实现,信贷选择效应并不显著,说明商业银行数字化转型所形成的风险积累,实际源自“融”而非“贷”。商业银行缺乏通过信贷溢价释放负债成本压力的能力,导致负债成本的增加最终形成风险积累。此结论可为商业银行更为精准地选择风险控制与管理的业务切入口提供启示。

基于稀疏光电探测阵列的轻武器终点弹道关键参数测量

为了有效、准确、可靠地获取轻武器终点弹道的关键参数(包括射击精度、弹丸飞行速度、弹道姿态角和射击频率等),提出了一种基于稀疏分布光电探测器阵列的测量方法。根据弹丸激波在终点弹道横截面的传播速度分布特性,结合稀疏光电探测阵列结构参数构建一种测量模型,精确解析出关键参数测量结果。通过数值模拟仿真分析测量误差变化规律,可知探测靶面内从中心向四周的坐标测量误差逐渐减小,姿态角测量误差随坐标差值的增大而减小,速度测量误差随靶距的增加而减小。实弹射击对比实验结果表明,该测量方法能够满足轻武器终点弹道关键参数测试要求,与以往的方法相比,具有探测靶面积足够大、无探测盲区、成本较低、安装调试方便等优点。

位移放大型黏滞阻尼装置的减震效果研究

为解决普通黏滞阻尼器性能在层间位移较小的结构或位置难以得到充分发挥的问题,提出一种基于杠杆原理将位移和速度放大的黏滞阻尼装置,该装置通过放大普通黏滞阻尼器两端的相对位移,进而放大相对速度,使阻尼器性能得以充分发挥,更好地达到降低结构地震响应的效果。以某实际工程结构为背景,通过SAP2000有限元软件建立有限元模型,分析原结构、附加普通黏滞阻尼器结构和附加放大型黏滞阻尼器结构在3条地震波作用下的地震响应。结果表明,在3条地震波作用下,相较于附加普通筒式黏滞阻尼器结构,附加放大型黏滞阻尼器结构的层间位移角和基底剪力降低幅度均较大,说明放大型黏滞阻尼器相较于普通黏滞阻尼器有更好的减震效果。

累积损伤对B炸药冲击起爆影响的仿真研究

采用LS-DYNA软件进行数值仿真,通过改变炸药撞击速度以改变损伤程度,探究损伤和垫层材料对B炸药起爆行为的影响。计算结果表明,当第2次撞击速度一定时,起爆时间t与第1次撞击速度v_(1)的关系为:t=-0.02 v_(1)+C_(1),冲击起爆的距离也随之减小。主要因为第1次撞击速度增大,导致B炸药发生轻微变形,内部的损伤程度随之增大,第2次撞击时更容易被起爆。3种不同垫层中,波阻抗较大的材料抗撞击能力强,B炸药内部不易产生损伤,冲击起爆的时间和距离较长;而B炸药的临界起爆压力差别不大,临界起爆压力的范围在31.4832.98 GPa之间。表明不同垫层材料会影响损伤后B炸药冲击起爆的时间和距离,而不会影响临界起爆压力。

气泡帷幕对爆破冲击波的削减效果及鱼类安全防护研究

航道整治工程中多采用水下爆破的方式对碍航礁石予以清除,爆破产生的冲击波会对鱼类安全存在一定的影响,目前多采用气泡帷幕的方式削减冲击波峰值压力。研究通过构建更接近实际的气泡帷幕数值模型,探明不同布置方式下气泡帷幕对爆破冲击波压力的削减效果及其作用下的鱼类存活最小体长。研究结果表明:气泡帷幕对冲击波压力的消减程度在前半段(65%~69%)大于后半段(10%~12%)。随着气泡体积占比的上升,气泡帷幕对冲击波峰值压力的削减率也随之提升,但当气泡体积占比达到40%后,削减率增幅减小且趋于平缓。气泡帷幕距爆源10、15、20 m下的鱼类存活最小体长分别为20~34、14~30、12~24 cm,气泡帷幕厚度为2、3、4 m下鱼类存活的最小体长分别为12~24、10~22、6~17 cm。研究结果可为航道整治工程实施下鱼类资源的保护提供理论依据。