Natural conditions and cropping regionalization of rice area in China

The formation of rice distribution is based on certain natural ecological conditions and social economic environments. In China, rice cropping is distributed in a vast area extending across 5 tempera ture belts, the northernmost of rice growing area in the world being in China. Distribution of rice cropping is characterized by a gradual decrease from south to north, from large and concentrated regions in Southeast to small and separated areas in Northwest. Natural conditions in rice regions differ in China with a varied topography, high in the west and low in the east. Rice fields in the west are mostly distributed on flatlands on plains, valleys among mountains, tablelands in river valleys, yellow-soil plains and basins in low valleys, alluvial plains, plains in river valleys, while those in the east are mainly distributed on alluvial plains, hilly areas among low mountains, coastal plains, along rivers and lakes and in basins among mountains.

OPTIMAL INTERIOR PARTIAL REGULARITY FOR NONLINEAR ELLIPTIC SYSTEMS UNDER THE NATURAL GROWTH CONDITION:THE METHOD OF A-HARMONIC APPROXIMATION

In this article, the authors consider the nonlinear elliptic systems under the natural growth condition. They use a new method introduced by Duzaar and Grotowski, for proving partial regularity for weak solutions, based on a generalization of the technique of harmonic approximation. And directly establish the optimal Holder exponent for the derivative of a weak solution.

Survey of thermal comfort in residential buildings under natural conditions in hot humid and cold wet seasons in Nanjing

Comfort standards(ISO 7730,ASHRAE 55)specify the exact physical criteria for producing acceptable thermal environments,such as temperature,air movement,and humidity limits.These,however,are often difficult to comply with,particularly in hot humid and cold wet seasons in Nanjing,China.Changing expectations of comfort is important in evaluating comfort,since naturally conditioned buildings in Nanjing are not typically airconditioned.For this objective,a field study was conducted during the summer of 2000 and the winter of 2001.A total of 600 participants each answered a subjective questionnaire.Analyzing these field data shows that in natural conditions,the influence of gender and age on people’s thermal sensations is insignificant compared with six main variables.In addition,people’s thermal discomfort rapidly increases along with growth in relative humidity.Further,the variation of people’s hot or cold sensations is in proportion to that of air movement,and the effect in winter is greater than that in summer.The range of acceptable temperatures in hot humid and cold wet Nanjing is between 14.14℃and 29.42℃.

REGULARITY FOR NONLINEAR ELLIPTIC SYSTEMS WITH DINI COEFFICIENTS UNDER NATURAL GROWTH CONDITION FOR THE CASE:1

In this article,we consider interior regularity for weak solutions to nonlinear elliptic systems of divergence type with Dini continuous coefficients under natural growth condition for the case 1〈m〈 2.All estimates in the case of m≥2 is no longer suitable,and we can’t obtain the Caccioppoli’s second inequality by using these techniques developed in the case of m≥2.But the Caccioppoli’s second inequality is the key to use A-harmonic approximation method.Thus,we adopt another technique introduced by Acerbi and Fcsco to overcome the difficulty and we also overcome those difficulties due to Dini condition.And then we apply the A-harmonic approximation method to prove partial regularity of weak solutions.

ON THE EIGENVALUE PROBLEM FOR ELLIPTIC SYSTEMS WITH STRONGLY EIGEN-EXPONENT UNDER NATURAL GROWTH CONDITIONS

Let Ω be a bounded domain with smooth boundary Ω in R~n. We consider the following eigenvalue problem for systems of elliptic equations under the natural growth conditions

EXISTENCE OF NONTRIVIAL SOLUTION OF QUASILINEAR ELLIPTIC EIGENVALUE PROBLEM ON R^n WITH NATURAL GROWTH CONDITIONS

In this paper, we get the existence result of the nontrivial weak solution (λ, u) of the following eigenvalue problem with natural growth conditions.

Induced noise of impeller stuck and passive rotation state in multi-stage pump without power drive under natural flow conditions

The natural flow cooling strategy is commonly employed in modern high-speed vessels and nuclear-powered submarines. These vessels rely on the energy generated by their own speed to drive the cooling system and supply cooling water to the condenser. The circulating pump, which operates without a motor drive under natural flow conditions, is a large resistance component in the cooling system. However, it is also the primary noise source, significantly impacting the vessel’s safe operation and acoustic stealth performance. This study investigates the induced noise characteristics of a multi-stage pump under natural flow conditions by experiment, computational fluid dynamics (CFD), and acoustic finite element method. The analysis encompasses the distribution of the flow field, variations in acoustic power, spectral features of flow-induced noise, and directivity of external field radiation noise under different natural flow conditions. The results show that the acoustic power distribution is correlated with the flow field. When the impeller is stuck, the noise sources primarily concentrate in the flow separation area at the blade’s leading edge, the interface area between the impeller and the guide vane, and the flow shock area inside the guide vane. Conversely, when the impeller rotates passively, the blade wake area has a higher acoustic power. The flow noise spectrum under natural flow conditions mainly exhibits broadband and discrete characteristics. Additionally, the pump structure influences the external field radiation noise, and its directivity varies with different flow rates and characteristic frequencies. This study provides valuable insights into optimal design to reduce the noise of the circulating pump in the vessel’s natural flow cooling system. It is essential for ensuring the safe operation and acoustic stealth performance of high-speed vessels and nuclear-powered submarines.

The Method of A-Harmonic Approximation and Boundary Regularity for Nonlinear Elliptic Systems under the Natural Growth Condition

We consider the questions of boundary regularity for weak solutions of second-order nonlinear elliptic systems under the natural growth condition. We obtain a general criterion for a weak solution to be regular in the neighborhood of a given boundary point. The proof yields directly the optimal regularity for the solution in this neighborhood. This result is new for the situation under the natural growth conditions.

OPTIMAL INTERIOR PARTIAL REGULARITY FOR NONLINEAR ELLIPTIC SYSTEMS WITH DINI CONTINUOUS COEFFICIENTS

In this article, we consider nonlinear elliptic systems of divergence type with Dini continuous coefficients. The authors use a new method introduced by Duzaar and Grotowski, to prove partial regularity for weak solutions, based on a generalization of the technique of harmonic approximation and directly establish the optimal HSlder exponent for the derivative of a weak solution on its regular set.

C^(1,α)-PARTIAL REGULARITY FOR NONLINEAR ELLIPTIC SYSTEMS

We prove C1.α-partial regularity of weak solutions of nonlinear elliptic systems under the main assumption that Aia and Bi satisfy the controllable growth condition or the natural growth condition.

THE HOLDER CONTINUITY OF GENERALIZED SOLUTIONS OF A CLASS QUASILINEAR PARABOLIC EQUATIONS

Let A and B satisfy the structural conditions (2), the local Holder continuity interior to Q = G X (0, T) is proved for the generalized solutions of quasilinear parabolic equations as follows: u(t) - divA(x, t, u, del u) + B(x, t, U, del u) = 0.

Orientation Field Guided Texture Synthesis

We present a framework for example-based texture synthesis with feature directions aligned to vector fields with 2-way rotational symmetry, also known as orientation fields. Through a simple variational formulation, the framework allows the user to design the orientation field with intuitive controls, by interactively manipulating singularities and field directions. The resulting field is then used to guide a parallel synthesis. Our contribution is twofold： a design tool for orientation fields with a natural boundary condition, and a parallel texture synthesis adapted specifically for using such fields in feature alignment. We demonstrate the advantages of the procedure through examples on planar and curved patches with trivial topology.