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"Zhao, Peng"
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الدفاع الوطني للصين
ظل موضوع الدفاع الوطني الصيني واحدا من الموضوعات التي حظيت باهتمام القارئ الأجنبي. وباعتبار الصين واحدة من البلدان الكبرى التي تتمتع بتنمية اقتصادية سريعة، فما هو الوضع الحالي لعملية تحديث الدفاع الوطني الصيني ؟ وما هي السياسات التي تعتمدها الصين تجاه قضايا الدفاع الوطني ؟ وما هي طرق تطوير الدفاع الوطني ؟ وما مدى مساهمته في السلام والاستقرار العالمي ؟ ويسعى كتاب (الدفاع الوطني الصيني) إلى البحث عن إجابات من خلال الواقع والوصول بالقارئ لمعرفة كل ما يتعلق بالدفاع الوطني الصيني.
Book
Migration of early aftershocks following the 2004 Parkfield earthquake
A significant number of the early aftershocks following large shallow earthquakes are missing in existing earthquake catalogues. An analysis of the waveforms of 3,647 relocated earthquakes along the Parkfield section of the San Andreas fault reveals 11 times more aftershocks within three days of the 2004 Parkfield earthquake than listed in a standard catalogue.
Large shallow earthquakes are immediately followed by numerous aftershocks. A significant portion of these events is missing in existing earthquake catalogues, mainly because seismicity after the mainshock can be masked by overlapping arrivals of waves from the mainshock and aftershocks
1
,
2
,
3
,
4
. However, recovery of the missing early aftershocks is important for understanding the physical mechanisms of earthquake triggering
2
,
3
,
4
, and for tracking postseismic deformation around the rupture zone associated with the mainshock
5
,
6
,
7
. Here we use the waveforms of 3,647 relocated earthquakes
8
along the Parkfield section of the San Andreas fault as templates
9
,
10
to detect missing aftershocks within three days of the 2004 magnitude 6.0 Parkfield earthquake. We identify 11 times more aftershocks than listed in the standard catalogue of the Northern California Seismic Network. We find that the newly detected aftershocks migrate in both along-strike and down-dip directions with logarithmic time since the mainshock, consistent with numerical simulations of the expansion of aftershocks caused by propagating afterslip
11
,
12
. The cumulative number of early aftershocks increases linearly with postseismic deformation in the first two days, supporting the view that aftershocks are driven primarily by afterslip
13
,
14
.
Journal Article
Achieving high strength and high ductility in magnesium alloy using hard-plate rolling (HPR) process
Magnesium alloys are highly desirable for a wide range of lightweight structural components. However, rolling Mg alloys can be difficult due to their poor plasticity and the strong texture yielded from rolling often results in poor plate forming ability, which limits their further engineering applications. Here we report a new hard-plate rolling (HPR) route which achieves a large reduction during a single rolling pass. The Mg-9Al-1Zn (AZ91) plates processed by HPR consist of coarse grains of 30–60 μm, exhibiting a typical basal texture, fine grains of 1–5 μm and ultrafine (sub) grains of 200–500 nm, both of the latter two having a weakened texture. More importantly, the HPR was efficient in gaining a simultaneous high strength and uniform ductility, i.e., ~371 MPa and ~23%, respectively. The superior properties should be mainly attributed to the cooperation effect of the multimodal grain structure and weakened texture, where the former facilitates a strong work hardening while the latter promotes the basal slip. The HPR methodology is facile and effective and can avoid plate cracking that is prone to occur during conventional rolling processes. This strategy is applicable to hard-to-deform materials like Mg alloys and thus has a promising prospect for industrial application.
Journal Article
كيف يحكم الحزب الشيوعي الصيني
مع التغيرات التاريخية وتقلبات الزمن، ظل العالم يتساءل : من أين جاءت مكانة الحزب الشيوعي الصيني في قلوب الصينيين والعالم ؟ وكيف حاز ثقة الصينيين وتأييدهم ؟ وكيف يتغلب على الصعاب ؟ وكيف يقود الصين في ثبات لبدء رحلة الاشتراكية التحديثية الجديدة، مواجهة التغير العميق لأوضاع العالم والدولة والحزب ؟ يجيب هذا الكتاب على هذه التساؤلات عبر جوانب مختلفة من وجهات النظر ويدقق النظر ويستقصي أمور الحزب الشيوعي الصيني، فيرصد أفعاله ويبحث أقواله ويحلل إنجازاته خلال هذا الوقت الذي اقترب فيه من تحقيق النهضة العظيمة للأمة الصينية أكثر من أي فترة على مر التاريخ وذلك بتمشيط الحقب والخبرات التي مر بها الحزب الشيوعي الصيني خلال توليه الحكم.
BOOK
A Fourth-order Compact ADI scheme for Two-Dimensional Nonlinear Space Fractional Schrödinger Equation
In this paper, a novel compact operator is derived for the approximation of the Riesz derivative with order $\\alpha\\in(1,2].$ The compact operator is proved with fourth-order accuracy. Combining the compact operator in space discretization, a linearized difference scheme is proposed for a two-dimensional nonlinear space fractional Schrodinger equation. It is proved that the difference scheme is uniquely solvable, stable, and convergent with order $O(\\tau arrow up +h pound sterling )$, where $\\tau$ is the time step size, $h=\\max\\{h_1,h_2\\}$, and $h_1,\\,h_2$ are space grid sizes in the $x$ direction and the $y$ direction, respectively. Based on the linearized difference scheme, a compact alternating direction implicit scheme is presented and analyzed. Numerical results demonstrate that the compact operator does not bring in extra computational cost but improves the accuracy of the scheme greatly.
Journal Article
تطوير إقتصاد دائري في الصين
هذا العمل الجماعي المشترك، كما يشير عنوانه : (التاريخ المديني الحضري للصين) هو كتاب حضاري بامتياز. كتاب يستعرض جوانب أساسية من حضارة الشعب الصيني القديمة-المتجددة الراسخة، الضاربة جذورها عميقا في تربة التاريخ البشري الشامل. يعد الكتاب سفر حضاري قيم وبحث متصل رصين حول التطور التاريخي العمراني في المدن الصينية وهو إذ يتناول بشكل أساسي، فن العمارة والبناء والتصميم وتخطيط المدن والشوارع والأحياء والأسواق والمقار الحكومية والحدائق والمعابد والساحات ومسالك الملاحة النهرية والري، فإنه لا يغفل في الوقت نفسه عن ما يتصل به هذا الموضوع، من عشرات المواضيع الحضارية والثقافية والمعيشية الأخرى، مثل : العبادات والاعتقادات والتقاليد والعادات والآداب والطقوس والحرف والفنون والنظم الاجتماعية والصراع السياسي والغزو الخارجي والتنظيم الحكومي والقبلي والاجتماعي والطبقي والعسكري والإداري والإنمائي والعمراني والإسكاني والتعليمي والتجاري والأدبي والفني والموسيقي والفولكلوري. إنه كتاب جميل يقدم العديد من اللوحات الرشيقة الرحبة المتقابلة المتلاحقة المتكاملة التي ترحل بنا بين القصور والأنهار والأسوار والأحياء والمعاهد والمعابد وهياكل عبادة الأجداد ومواقع التنقيب والساحات والحدائق والميادين ودواوين الشعر وسجلات التاريخ ولا يخلو كل ذلك من جولات من البحث المقارن في غير أمر من هذه الأمور ولن نطيل عليكم في الإضاءة على مواضيع هذا الكتاب لأكثر من ذلك، آملين لكم سلاسة القراءة ومتعة الاكتشاف.
Book
Molecular Catalysts for OER/ORR in Zn–Air Batteries
Zn–air batteries are becoming the promising power source for small electronic devices and electric vehicles. They provide a relatively high specific energy density at relatively low cost. This review presents exciting advances and challenges related to the development of molecular catalysts for cathode reactions in Zn–air batteries. Bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play the main role in improving performance of reversible fuel cell and metal–air batteries. The catalyst development strategies are reviewed, along with strategies to enhance catalyst performance by application of magnetic field. Proper design of bifunctional molecular ORR/OER catalysts allows the prolongment of the battery reversibility to a few thousand cycles and reach of energy efficiencies of over 70%.
Journal Article
Molybdenum isotopes unmask slab dehydration and melting beneath the Mariana arc
How serpentinites in the forearc mantle and subducted lithosphere become involved in enriching the subarc mantle source of arc magmas is controversial. Here we report molybdenum isotopes for primitive submarine lavas and serpentinites from active volcanoes and serpentinite mud volcanoes in the Mariana arc. These data, in combination with radiogenic isotopes and elemental ratios, allow development of a model whereby shallow, partially serpentinized and subducted forearc mantle transfers fluid and melt from the subducted slab into the subarc mantle. These entrained forearc mantle fragments are further metasomatized by slab fluids/melts derived from the dehydration of serpentinites in the subducted lithospheric slab. Multistage breakdown of serpentinites in the subduction channel ultimately releases fluids/melts that trigger Mariana volcanic front volcanism. Serpentinites dragged down from the forearc mantle are likely exhausted at >200 km depth, after which slab-derived serpentinites are responsible for generating slab melts.
How the subducted oceanic lithosphere provides fluids and melts to flux the subarc mantle source of arc magmas is controversial. Here the authors use Mo and other isotopes to show serpentinites formed in both the forearc mantle and the subducted lithosphere contribute to generating arc magmas.
Journal Article
Structure and activation mechanism of the hexameric plasma membrane H+-ATPase
The
S. cerevisiae
plasma membrane H
+
-ATPase, Pma1, is a P3A-type ATPase and the primary protein component of the membrane compartment of Pma1 (MCP). Like other plasma membrane H
+
-ATPases, Pma1 assembles and functions as a hexamer, a property unique to this subfamily among the larger family of P-type ATPases. It has been unclear how Pma1 organizes the yeast membrane into MCP microdomains, or why it is that Pma1 needs to assemble into a hexamer to establish the membrane electrochemical proton gradient. Here we report a high-resolution cryo-EM study of native Pma1 hexamers embedded in endogenous lipids. Remarkably, we found that the Pma1 hexamer encircles a liquid-crystalline membrane domain composed of 57 ordered lipid molecules. The Pma1-encircled lipid patch structure likely serves as the building block of the MCP. At pH 7.4, the carboxyl-terminal regulatory α-helix binds to the phosphorylation domains of two neighboring Pma1 subunits, locking the hexamer in the autoinhibited state. The regulatory helix becomes disordered at lower pH, leading to activation of the Pma1 hexamer. The activation process is accompanied by a 6.7 Å downward shift and a 40° rotation of transmembrane helices 1 and 2 that line the proton translocation path. The conformational changes have enabled us to propose a detailed mechanism for ATP-hydrolysis-driven proton pumping across the plasma membrane. Our structures will facilitate the development of antifungal drugs that target this essential protein.
The plasma membrane H
+
-ATPase is responsible for maintenance of the plasma membrane potential, which provides energy for the transport of nutrients, and the plasma membrane H
+
-ATPase in
S. cerevisiae
(Pma1) is a P3A-type ATPase that assembles and functions as a hexamer. Here, the authors present the cryo-EM structures of autoinhibited and activated native Pma1 hexamers purified with endogenous lipids and they propose a mechanism for proton pumping across the membrane by this family of H
+
-ATPases.
Journal Article