555 research outputs found
Perpustakaan Umum Malang Dengan Kombinasi Taman Vertikal Dan Ventilasi Untuk Perancangan Ruang Baca
Kualitas udara dalam ruang merupakan sebuah interaksi yang dapat berubah baiksecara konstan mau pun tidak yang diakibatkan oleh beberapa faktor yangmempengaruhi baik dari lingkungan luar mau pun lingkungan dalam. Salah saturuangan yang berpotensi tinggi untuk mengalami masalah polusi udara dalam ruangadalah ruang perpustakaan. Hal ini disebabkan oleh kondisi lingkungan eksternalseperti debu yang terbawa angin dan kondisi internal yaitu bakteri yang terbawa padabuku-buku lama yang dihirup oleh pelaku aktifitas perpustakaan. Dari faktor eksternal,salah satu penyebabnya ialah debu, tanah, dan polutan yang terbawa di udara masuk kedalam ruang perpustakaan. Pengoperasian sistem ventilasi bangunan berperan pentingdalam membawa udara masuk ke dalam ruangan. Salah satu strategi yang telahdisebutkan ialah penggunaan filter. Filter pada ventilasi berfungsi sebagai penyerappolusi yang terbawa angin luar masuk ke ruang dalam. Terdapat beberapa cara untukfiltrasi pada bangunan salah satunya adalah taman vertikal. Diharapkan penggunaankombinasi taman vertikal dan ventilasi dapat menjadi sumber penghawaan alami yangtetap memperhatikan kualitas udara dalam pada perpustakaan agar masalah buruknyakualitas udara ruang dalam pada perpustakaan dapat direduksi
Colour image representation by scalar variables
A number of studies have shown that it is possible to use a colour codebook, which has a limited
number of colours (typically 100-200), to replace the colour gamut and obtain a good quality reconstructed
colour image. Thus colour images can be displayed on less expensive devices retaining
high quality and can be stored in less space. However, a colour codebook is normally randomly
arranged and the coded image, which is referred to as the index image, has no structure. This prevents
the use of this kind of colour image representation in any further image processing.
The objective of the research described in this thesis is to explore the possibility of making the index
image meaningful, that is, the index image can retain the structure existing in the original full
colour image, such as correlation and edges. In this way, a three band colour image represented by
colour vectors can be transfomled into a one band index image represented by scalar variables. To achieve the scalar representation of colour images, the colour codebook must be ordered to satisfy
the following two conditions: (I) codewords representing similar colours must be close together
in the code book and (2) close code words in the codebook must represent similar colours. Some
effective methods are proposed for ordering the colour codebook. First, several grouping strategies
are suggested for grouping the code words representing similar colours together. Second, an ordering
function is designed, which gives a quantity. measurement of the satisfaction of the two conditions
of an ordered codebook. The code book ordering is then iteratively refined by the ordering
function. Finally, techniques, such as artificial codeword insertion, are developed to refine the
code book ordering further.
A number of algorithms for colour codebook ordering have been tried to retain as much structure in the index image as possible. The efficiency of the algorithms for ordering a colour codebook has
been tested by applying some image processing techniques to the index image. A VQ/DCT colour
image coding scheme has been developed to test the possibility of compressing and decompressing
the index image. Edge detection is applied to the index image to test how well the edges existing
in the original colour image can be retained in the index image.
Experiments demonstrate that the index image can retain a lot of structure existing in the original
colour image if the codebook is ordered by an appreciate ordering algorithm, such as the PNNbased/
ordering function method together with artificial codeword insertion. Then further image
processing techniques, such as image compression and edge detection, can be applied to the index
image. In this way, colour image processing can be realized by index image processing in the same
way as monochrome image processing. In this sense, a three-band colour image represented by colour
vectors is transformed into a single band index image represented by scalar variables
Giant Optical Second Harmonic Generation in Two-Dimensional Multiferroics
Nonlinear optical
properties of materials such as second and higher
order harmonic generation and electro-optic effect play pivotal roles
in lasers, frequency conversion, electro-optic modulators, switches,
and so forth. The strength of nonlinear optical responses highly depends
on intrinsic crystal symmetry, transition dipole moments, specific
optical excitation, and local environment. Using first-principles
electronic structure theory, here we predict giant second harmonic
generation (SHG) in recently discovered two-dimensional (2D) ferroelectric–ferroelastic
multiferroics–group IV monochalcogenides (i.e., GeSe, GeS,
SnSe, and SnS). Remarkably, the strength of SHG susceptibility in
GeSe and SnSe monolayers is more than 1 order of magnitude higher
than that in monolayer MoS<sub>2</sub>, and 2 orders of magnitude
higher than that in monolayer hexagonal BN. Their extraordinary SHG
is dominated by the large residual of two opposite intraband contributions
in the SHG susceptibility. More importantly, the SHG polarization
anisotropy is strongly correlated with the intrinsic ferroelastic
and ferroelectric orders in group IV monochalcogenide monolayers.
Our present findings provide a microscopic understanding of the large
SHG susceptibility in 2D group IV monochalcogenide multiferroics from
first-principles theory and open up a variety of new avenues for 2D
ferroelectrics, multiferroics, and nonlinear optoelectronics, for
example, realizing active electrical/optical/mechanical switching
of ferroic orders in 2D multiferroics and in situ ultrafast optical
characterization of local atomistic and electronic structures using
noncontact noninvasive optical SHG techniques
Metal-Free Oxidative Spirocyclization of Hydroxymethylacrylamide with 1,3-Dicarbonyl Compounds: A New Route to Spirooxindoles
A metal-free oxidative spirocyclization of hydroxymethylacrylamide with 1,3-dicarbonyl compounds is described. The reaction proceeds through tandem dual C–H functionalization and intramolecular dehydration, in which two new C–C bonds and one C–O bond were formed. This method affords a novel and straightforward access to various spirooxindoles under mild conditions
Palladium-Catalyzed Alkylarylation of Acrylamides with Unactivated Alkyl Halides
An efficient palladium-catalyzed
alkylarylation of acrylamides
with unactivated alkyl halides has been developed. This method is
highlighted by its broad substrate scope and excellent functional
group tolerance. In addition to alkyl halides, fluoroalkyl halides
and benzyl bromides also participated well in this transformation.
A detailed mechanistic investigation suggests that a radical pathway
is probably involved in the cyclization process
Aryl Fluorosulfate Trapped Staudinger Reduction
A chemoselective
Staudinger reduction/sulfurÂ(VI) fluoride exchange
cascade has been developed to join two chemical segments through an
aryl sulfamate ester (RNH–SO<sub>2</sub>–OAr) linkage.
Aryl fluorosulfate is exploited in this work as the first tetrahedral
electrophilic trap for the in situ generated iminophosphorane. Ten
examples using azide-containing compounds are presented
SUs’ forced termination probability with reserved channels.
<p>SUs’ forced termination probability with reserved channels.</p
Cross-statistical analysis of e-commerce participation and the use intensity of organic fertilizers.
Cross-statistical analysis of e-commerce participation and the use intensity of organic fertilizers.</p
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