ClassID:

88875

C04B35/49 - CPC Classification

Classification description:

Shaped ceramic products characterised by their composition ; Ceramics compositions ; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates containing also titanium oxides or titanates

Sub-classes:
Recent Application in this class:
#1
20260051441
2026-02-19

MULTILAYER ELECTRONIC COMPONENT

#2
20260051439
2026-02-19

CONDUCTIVE PASTE

#3
20260028285
2026-01-29

ZIRCONIA COMPOSITIONAL SUBSTANCE AND METHOD FOR PRODUCING THE SAME

#4
20250326695
2025-10-23

ZIRCONIA COMPOSITE SINTERED BODY AND METHOD FOR PRODUCING SAME

#5
20250326694
2025-10-23

BLACK ZIRCONIA COMPOSITE SINTERED BODY AND METHOD FOR MANUFACTURING SAME

#6
20250304502
2025-10-02

DIELECTRIC CERAMIC COMPOSITION AND MULTILAYER CERAMIC ELECTRONIC DEVICE

#7
20250223231
2025-07-10

GLASS-CERAMIC COMPOSITION, GLASS-CERAMIC SINTERED BODY, AND ELECTRONIC COMPONENT

#8
20240355544
2024-10-24

MULTILAYER ELECTRONIC COMPONENT

#9
20240317646
2024-09-26

LEAD-FREE PIEZOELECTRIC CERAMIC COMPOSITION AND PIEZOELECTRIC ELEMENT

#10
20240222017
2024-07-04

CONDUCTIVE PASTE

#11
20240215449
2024-06-27

POWER-GENERATING METHOD AND POWER-GENERATING SYSTEM

#12
20240101482
2024-03-28

STABILIZED ZIRCONIA SINTERED BODY AND ZIRCONIA POWDER

#13
20240076242
2024-03-07

MULTILAYER CERAMIC CAPACITOR

#14
20230406775
2023-12-21

HIGH-ZIRCONIA ELECTRO-FUSED CAST REFRACTORY MATERIAL

#15
20230386745
2023-11-30

Dielectric composition and multilayer ceramic electronic component

#16
20230303451
2023-09-28

DIELECTRIC COMPOSITION AND MULTILAYER CERAMIC ELECTRONIC DEVICE

#17
20230117106
2023-04-20

Process for 3D printing

#18
20220344574
2022-10-27

Lead-free piezoelectric ceramic sensor material and a preparation method thereof

#19
20220332650
2022-10-20

METHOD FOR THE PREPARATION OF A LEAD-FREE PIEZOELECTRIC MATERIAL AND PRECURSOR SOLUTION

#20
20220221359
2022-07-14

PRESSURE SENSOR CERAMIC MATERIAL AND PREPARATION METHOD THEREOF

#21
20220220036
2022-07-14

Multilayer ceramic capacitor

#22
20220209100
2022-06-30

METHOD OF PREPARING A SOLID SOLUTION CERAMIC MATERIAL HAVING INCREASED ELECTROMECHANICAL STRAIN, AND CERAMIC MATERIALS OBTAINABLE THEREFROM

#23
20210305492
2021-09-30

METHOD OF MANUFACTURING PIEZOELECTRIC ELEMENT, METHOD OF MANUFACTURING ELECTRONIC DEVICE, PIEZOELECTRIC ELEMENT, AND ELECTRONIC DEVICE

#24
20210300828
2021-09-30

Black sintered body and method for producing the same

#25
20210292240
2021-09-23

INORGANIC MATERIAL POWDER AND METHOD OF MANUFACTURING A STRUCTURAL BODY

#26
20210206697
2021-07-08

Sn-Zn-O-BASED OXIDE SINTERED BODY AND METHOD FOR PRODUCING THE SAME

#27
20210061717
2021-03-04

Zirconia sintered body and manufacturing method of the same

#28
20200397542
2020-12-24

Process for 3D printing

#29
20200165166
2020-05-28

Multilayer ceramic capacitor

#30
20200126723
2020-04-23

Dielectric ceramic composition and multilayer ceramic capacitor

#31
20200051742
2020-02-13

Multilayer ceramic capacitor with dielectric layers including dielectric grains having a core-shell structure

#32
20200043658
2020-02-06

Dielectric composition and electronic component using the same

#33
20200043657
2020-02-06

Multilayer ceramic electronic component

#34
20200039887
2020-02-06

Dielectric ceramic composition and multilayer ceramic electronic component

#35
20200010370
2020-01-09

Ceramic material comprising a pseudo-cubic phase, a process for preparing and uses of the same

#36
20190378970
2019-12-12

Piezoelectric ceramics, piezoelectric element, and electronic apparatus

#37
20190237257
2019-08-01

Dielectric ceramic composition, electronic device, and multilayer ceramic capacitor

#38
20190237255
2019-08-01

Dielectric ceramic composition and multilayer ceramic capacitor

#39
20190237254
2019-08-01

Dielectric ceramic composition and multilayer ceramic capacitor

#40
20190189346
2019-06-20

Multilayer ceramic capacitor

#41
20190131071
2019-05-02

Ceramic sintered body and passive component including the same

#42
20190100465
2019-04-04

Multilayer ceramic capacitor

#43
20190096578
2019-03-28

Multi-layer ceramic capacitor

#44
20190039957
2019-02-07

Low-temperature co-fired microwave dielectric ceramic material, and preparation method and application thereof

#45
20180370858
2018-12-27

Method for making housing for mobile communication device

#46
20180330843
2018-11-15

Electrically conductive oxide sintered compact, member for electrical conduction, gas sensor, piezoelectric element, and method for producing piezoelectric element

#47
20180298215
2018-10-18

Process for 3D printing

#48
20180297036
2018-10-18

BEAD MADE OF A FUSED PRODUCT

#49
20180282226
2018-10-04

Zirconium tin titanate compositions, ceramic bodies comprising same, and methods of manufacturing same

#50
20180261388
2018-09-13

Dielectric material, method of manufacturing thereof, and dielectric devices and electronic devices including the same

#51
20180247767
2018-08-30

Nanocrystal film-coated substrate, manufacturing method of same, and manufacturing method of barium zirconate titanate nanocrystal

#52
20180240594
2018-08-23

Dielectric composition, dielectric element, electronic device, and multilayer electronic device

#53
20180086672
2018-03-29

Enhanced fracture toughness thermal barrier coating material

#54
20170287636
2017-10-05

Dielectric ceramic composition and multilayer ceramic capacitor

#55
20170287635
2017-10-05

Dielectric ceramic composition and multilayer ceramic capacitor

#56
20170283328
2017-10-05

Dielectric ceramic composition and multilayer ceramic capacitor

#57
20170236994
2017-08-17

PRECURSOR SOLUTION AND METHOD FOR THE PREPARATION OF A LEAD-FREE PIEZOELECTRIC MATERIAL

#58
20170200557
2017-07-13

COG dielectric composition for use with nickel electrodes

#59
20170162323
2017-06-08

Ceramic dielectric composition and multilayer ceramic capacitor containing the same

#60
20170152186
2017-06-01

Precursor solution and method for the preparation of a lead-free piezoelectric material

#61
20170133155
2017-05-11

Multilayer ceramic capacitor

#62
20170101345
2017-04-13

PIEZOELECTRIC CERAMICS, AND PIEZOELECTRIC ELEMENT, AND ELECTRONIC EQUIPMENT CONTAINING PIEZOELECTRIC CERAMICS

#63
20170088470
2017-03-30

High zirconia electrically fused cast refractory

#64
20170040528
2017-02-09

Piezoelectric element oscillatory wave motor and optical apparatus

#65
20170018358
2017-01-19

Multilayer ceramic capacitor

#66
20170008806
2017-01-12

DIELECTRIC CERAMIC COMPOSITION AND MULTILAYER CERAMIC CAPACITOR CONTAINING THE SAME

#67
20160365502
2016-12-15

Piezoelectric material, piezoelectric element, and electronic apparatus

#68
20160315245
2016-10-27

Piezoelectric material, piezoelectric element, and electronic apparatus

#69
20160307701
2016-10-20

Dielectric ceramic composition and multilayer ceramic capacitor containing the same

#70
20160268045
2016-09-15

Dielectric ceramic composition and ceramic electronic device

#71
20160264474
2016-09-15

Dielectric ceramic composition and ceramic electronic device

#72
20160240313
2016-08-18

COG dielectric composition for use with nickel electrodes

#73
20160233414
2016-08-11

Piezoelectric element, multilayered piezoelectric element, liquid discharge head, liquid discharge apparatus, ultrasonic motor, optical apparatus, and electronic apparatus

#74
20160229751
2016-08-11

Zirconium oxide-titanium oxide composite sol and production method thereof

#75
20160203912
2016-07-14

Ceramic multi-layer capacitor based on BaTi(1-y)ZryO3

#76
20160163458
2016-06-09

Ceramic dielectric composition and multilayer ceramic capacitor containing the same

#77
20160111217
2016-04-21

Laminated ceramic capacitor

#78
20160071987
2016-03-10

Method for fabricating photoelectric conversion material

#79
20160071649
2016-03-10

Laminated ceramic capacitor

#80
20160027587
2016-01-28

Thin-film dielectric and thin-film capacitor element

#81
20160023955
2016-01-28

High zirconia fused cast refractory

#82
20160023954
2016-01-28

Method of preparing ceramic powders

#83
20160016853
2016-01-21

Zirconia sintered body, and zirconia composition and calcined body

#84
20160002114
2016-01-07

Dielectric ceramic composition and composite ceramic structure

#85
20160002113
2016-01-07

Dielectric ceramic composition and composite ceramic structure

#86
20150349239
2015-12-03

Piezoelectric material, piezoelectric element, and electronic device

#87
20150295161
2015-10-15

Piezoelectric material, piezoelectric element, multilayered piezoelectric element. Liquid discharge heard, liquid discharge apparatus, ultrasonic motor, optical apparatus, vibratory apparatus, dust removing device, image pickup apparatus, and electronic equipment

#88
20150295160
2015-10-15

Piezoelectric material, piezoelectric element, multilayered piezoelectric element, liquid discharge head, liquid discharge apparatus, ultrasonic motor, optical apparatus, vibratory apparatus, dust removing device, image pickup apparatus, and electronic equipment

#89
20150274600
2015-10-01

Dielectric composition and electronic component

#90
20150183690
2015-07-02

Machinable zirconia comprising titania nanopowder

#91
20150155099
2015-06-04

Laminated ceramic capacitor and manufacturing method therefor

#92
20150098166
2015-04-09

DIELECTRIC COMPOSITION AND MULTILATER CERAMIC ELECTRONIC COMPONENT MANUFACTURED USING THE SAME

#93
20150083978
2015-03-26

Composite perovskite powder, preparation method thereof, and paste composition for internal electrode having the same

#94
20150007614
2015-01-08

Refractory product having a high content of zirconia

#95
20140378295
2014-12-25

Amorphous dielectric film and electronic component

#96
20140334994
2014-11-13

Zircon components

#97
20140313634
2014-10-23

Dielectric composition, multilayer ceramic capacitor using the same, and method for manufacturing multilayer ceramic capacitor

#98
20140234653
2014-08-21

Thermal spray powder and film that contain rare-earth element, and member provided with film

#99
20140145125
2014-05-29

High-strength transparent zirconia sintered body, process for producing the same, and uses thereof

#100
20140145106
2014-05-29

Piezoelectric material

#101
20140138689
2014-05-22

Photoelectric conversion material

#102
20140135203
2014-05-15

Dielectric composition and preparation method thereof

#103
20140131611
2014-05-15

Piezoelectric material

#104
20140125199
2014-05-08

Piezoelectric element, oscillatory wave motor, and optical apparatus

#105
20140117811
2014-05-01

Piezoelectric element, multilayered piezoelectric element, liquid discharge head, liquid discharge apparatus, ultrasonic motor, optical apparatus, and electronic apparatus

#106
20140092525
2014-04-03

Dielectric composition and multilayer ceramic electronic component manufactured using the same

#107
20140043722
2014-02-13

Laminated ceramic capacitor

#108
20140030163
2014-01-30

PRODUCT OF CHROMIUM OXIDE, ZIRCONIUM OXIDE AND HAFNIUM OXIDE

#109
20140011660
2014-01-09

ATZ fused grains

#110
20140005029
2014-01-02

Method of manufacturing perovskite powder, perovskite powder manufactured by the same and multilayer ceramic electronic component

#111
20130294007
2013-11-07

Multilayer ceramic capacitor and method for manufacturing multilayer ceramic capacitor

#112
20130293320
2013-11-07

Dielectric ceramic and dielectric filter having the same

#113
20130228715
2013-09-05

Ceramic material based on the perovskite ceramic Bi0, 5Na0, 5TiO3, piezoelectric actuator containing the ceramic material and process for producing the ceramic material

#114
20130222971
2013-08-29

Method for manufacturing laminated ceramic capacitor

#115
20130222968
2013-08-29

Dielectric ceramic and laminated ceramic capacitor using the same

#116
20130217562
2013-08-22

Colored translucent zirconia sintered body, its production process and its use

#117
20130194717
2013-08-01

Dielectric ceramic, stack ceramic electronic component, and method of manufacturing these

#118
20130168596
2013-07-04

Pb(Hf,Ti)Obased high performance polycrystalline piezoelectric materials

#119
20130165313
2013-06-27

FERROELECTRIC FILM, SOL-GEL SOLUTION, FILM FORMING METHOD AND METHOD FOR MANUFACTURING FERROELECTRIC FILM

#120
20120270720
2012-10-25

DIELECTRIC CERAMIC-FORMING COMPOSITION AND DIELECTRIC CERAMIC MATERIAL

#121
20120241990
2012-09-27

Ceramic material, method for producing the ceramic material, and resistor component comprising the ceramic material

#122
20120147524
2012-06-14

Dielectric ceramic composition and laminated ceramic capacitor

#123
20120147523
2012-06-14

METHOD OF MANUFACTURING PEROVSKITE POWDER, PEROVSKITE POWDER MANUFACTURED BY THE SAME AND MULTILAYER CERAMIC ELECTRONIC COMPONENT

#124
20120141701
2012-06-07

Zircon components

#125
20120127629
2012-05-24

DOPED ZrO2 CAPACITOR MATERIALS AND STRUCTURES

#126
20120075770
2012-03-29

Dielectric ceramic and laminated ceramic capacitor

#127
20120058883
2012-03-08

High-strength transparent zirconia sintered body, process for producing the same, and uses thereof

#128
20110287925
2011-11-24

METHOD OF PREPARING CERAMIC POWDERS USING AMMONIUM OXALATE

#129
20110240746
2011-10-06

RADIO FREQUENCY IDENTIFICATION TAG USING A RELAXOR FERROELECTRIC SUBSTRATE HAVING A MICRO POLAR REGION AND METHOD FOR MANUFACTURING THE SAME

#130
20110235233
2011-09-29

Electronic device and method for producing electronic device

#131
20110233723
2011-09-29

DIELECTRIC FILM AND SEMICONDUCTOR DEVICE

#132
20110228443
2011-09-22

Dielectric ceramic composition and temperature compensation laminated capacitor

#133
20110212382
2011-09-01

High energy density ionic dielectric materials and devices

#134
20110205687
2011-08-25

Dielectric ceramic and laminated ceramic capacitor

#135
20110195835
2011-08-11

DIELECTRIC CERAMIC COMPOSITION AND ELECTRONIC DEVICE

#136
20110195178
2011-08-11

PRODUCTION METHOD OF DIELECTRIC CERAMIC COMPOSITION AND PRODUCTION METHOD OF ELECTRONIC DEVICE

#137
20110183834
2011-07-28

MODIFIED PEROVSKITE TYPE COMPOSITE OXIDE, METHOD FOR PREPARING THE SAME, AND COMPOSITE DIELECTRIC MATERIAL

#138
20110157769
2011-06-30

Dielectric ceramic composition and multilayer ceramic capacitor having the same

#139
20110152060
2011-06-23

METHOD OF PREPARING CERAMIC POWDERS USING CHELATE PRECURSORS

#140
20110128665
2011-06-02

Ceramic Capacitors for High Temperature Applications

#141
20110121096
2011-05-26

Piezoelectric device, piezoelectric device manufacturing method, and liquid discharge apparatus

#142
20110114481
2011-05-19

Lanthanum Oxide-based Sintered Compact, Sputtering Target Composed of said Sintered Compact, Method of Producing Lanthanum Oxide-based Sintered Compact, and Method of Producing Sputtering Target based on said Production Method

#143
20110104469
2011-05-05

Method of hydrothermal liquid phase sintering of ceramic materials and products derived therefrom

#144
20110090619
2011-04-21

COG dieletric composition for use with nickel electrodes

#145
20110070441
2011-03-24

Zirconia sintered body and production method the same

#146
20110039684
2011-02-17

FUSED CERAMIC PRODUCT, METHOD OF FABRICATION AND USES

#147
20110037015
2011-02-17

Lead-free piezoelectric material

#148
20110002083
2011-01-06

Ceramic material and electronic device

#149
20100331169
2010-12-30

Method of forming a dielectric powder using a precipitated precursor powder

#150
20100328844
2010-12-30

Dielectric ceramic and manufacturing method therefor and laminated ceramic capacitor

#151
20100327213
2010-12-30

Turbine engine components

#152
20100311564
2010-12-09

Dielectric Oxide Films and Method for Making Same

#153
20100285947
2010-11-11

Method of preparing ceramic powders

#154
20100284126
2010-11-11

Dielectric ceramic and multilayer ceramic capacitor

#155
20100283167
2010-11-11

METHODS OF MAKING CERAMIC FIBERS AND BEADS

#156
20100248938
2010-09-30

Passive optoceramics with cubic crystal structure, process for manufacturing the same and their uses

#157
20100234216
2010-09-16

Ceramic materials for 4-way and NOx adsorber and method for making same

#158
20100193739
2010-08-05

Active optoceramics with cubic crystal structure, method of production of the optoceramics, and uses thereof

#159
20100193738
2010-08-05

ACTIVE OPTOCERAMICS WITH CUBIC CRYSTAL STRUCTURE, METHOD OF PRODUCTION OF THE OPTOCERAMICS, AND USES THEREOF

#160
20100170705
2010-07-08

Method for producing forsterite powder, forsterite powder, sintered forsterite, insulating ceramic composition, and multilayer ceramic electronic component

#161
20100165541
2010-07-01

Dielectric ceramics, and laminated ceramic capacitor

#162
20100093516
2010-04-15

Pyrochlore materials and a thermal barrier coating with these pyrochlore materials

#163
20100044771
2010-02-25

Zr-Sn-Ti-O films

#164
20100035748
2010-02-11

Dielectric ceramic composition and an electronic component

#165
20100028698
2010-02-04

Plasma-spray powder manufacture technique

#166
20100014210
2010-01-21

Dielectric ceramic material and monolithic ceramic capacitor

#167
20100004110
2010-01-07

Method for making glass frit powders using aerosol decomposition

#168
20090270252
2009-10-29

Acid resistant ceramic materials, filter using the same, and preparation of them

#169
20090250850
2009-10-08

Process for preparing advanced ceramic powders using onium dicarboxylates

#170
20090246541
2009-10-01

Dielectric ceramic composition, an electric component and a manufacturing method thereof

#171
20090244804
2009-10-01

C0G multi-layered ceramic capacitor

#172
20090235692
2009-09-24

Sag control of isopipes used in making sheet glass by the fusion process

#173
20090207551
2009-08-20

Dielectric ceramic and multilayer ceramic capacitor using the same

#174
20090149312
2009-06-11

Dielectric ceramic composition and electric device

#175
20090142578
2009-06-04

Method of hydrothermal liquid phase sintering of ceramic materials and products derived therefrom

#176
20090140197
2009-06-04

Piezoelectric element containing perovskite type oxide, and liquid jet head and ultrasonic motor using the piezoelectric element

#177
20090137381
2009-05-28

Dielectric ceramic composition and method of production thereof

#178
20090128989
2009-05-21

Dielectric ceramic, ceramic electronic element, and multilayer ceramic capacitor

#179
20090108962
2009-04-30

Dielectric filter for base station communication equipment

#180
20090088315
2009-04-02

Dielectric ceramic composition and an electric device

#181
20090046411
2009-02-19

C0G multi-layered ceramic capacitor

#182
20090046410
2009-02-19

Dielectric ceramics and multi-layer ceramic capacitor using same

#183
20090011923
2009-01-08

Dielectric porcelain composition and electronic component

#184
20080305944
2008-12-11

DIELECTRIC CERAMICS AND MANUFACTURING METHOD THEREOF, AS WELL AS MULTILAYER CERAMIC CAPACITOR

#185
20080297979
2008-12-04

Dielectric ceramic composition and electronic device

#186
20080280748
2008-11-13

Dielectric ceramic-forming composition

#187
20080253954
2008-10-16

Method for producing powder forsterite powder, forsterite powder, sintered forsterite, insulating ceramic composition, and multilayer ceramic electronic component

#188
20080237531
2008-10-02

Piezoelectric ceramic composition

#189
20080203627
2008-08-28

Ceramic materials for 4-way and NOadsorber and method for making same

#190
20080193776
2008-08-14

Nonreducing dielectric ceramic, and manufacturing method and monolithic ceramic capacitor of the same

#191
20080139377
2008-06-12

Sag control of isopipes used in making sheet glass by the fusion process

#192
20080112109
2008-05-15

Dielectric ceramic and multilayer ceramic capacitor

#193
20080107800
2008-05-08

C0G multi-layered ceramic capacitor

#194
20080068777
2008-03-20

Multi-layer ceramic capacitor

#195
20080067898
2008-03-20

Piezoelectric element, and liquid jet head and ultrasonic motor using the piezoelectric element

#196
20080063881
2008-03-13

COG dielectric composition for use with nickel electrodes

#197
20080044344
2008-02-21

Process for production of powder of perovskite compound

#198
20080031796
2008-02-07

Method of preparing ceramic powders using ammonium oxalate

#199
20080009404
2008-01-10

Dielectric ceramic material

#200
20080006365
2008-01-10

Production method of multilayer ceramic electronic device

#201
20070287625
2007-12-13

Electronic device, dielectric ceramic composition and the production method

#202
20070284792
2007-12-13

Electronic device, dielectric ceramic composition and the production method

#203
20070275158
2007-11-29

C0G multi-layered ceramic capacitor

#204
20070268652
2007-11-22

Ceramic material and laminated ceramic condenser comprised thereof

#205
20070259104
2007-11-08

C0G multi-layered ceramic capacitor

#206
20070254799
2007-11-01

DIELECTRIC CERAMICS AND MULTI-LAYER CERAMIC CAPACITOR

#207
20070236865
2007-10-11

Dielectric ceramic and multilayer ceramic capacitor

#208
20070203014
2007-08-30

Dielectric ceramic composition and the production method

#209
20070148065
2007-06-28

Method of preparing ceramic powders using chelate precursors

#210
20070142210
2007-06-21

Dielectric ceramic and monolithic ceramic capacitor

#211
20070131142
2007-06-14

Barium Titanate Thin Films with Titanium Partially Substituted by Zirconium, Tin or Hafnium

#212
20070009719
2007-01-11

Multilayer ceramic capacitor and method for manufacturing the same

#213
20060276325
2006-12-07

Dielectric ceramic capacitor comprising non-reducible dielectric

#214
20060234854
2006-10-19

Dielectric ceramic composition and electronic device

#215
20060234853
2006-10-19

Dielectric ceramic composition, electronic device and production methods of the same

#216
20060229188
2006-10-12

C0G multi-layered ceramic capacitor

#217
20060177678
2006-08-10

Laminated ceramic capacitor

#218
20060160692
2006-07-20

Electronic device, dielectric ceramic composition and the production method

#219
20060126266
2006-06-15

Ceramic powder composition, ceramic material, and laminated ceramic condenser comprised thereof

#220
20060114641
2006-06-01

Multilayer ceramic capacitor and method for manufacturing the same

#221
20060045840
2006-03-02

Process for preparing perovskite-type crystalline compound powders

#222
20050282403
2005-12-22

Ceramic electronic device and the production method

#223
20050209090
2005-09-22

Dielectric ceramic composition and multilayer ceramic part using the same

#224
20050164521
2005-07-28

Zr-Sn-Ti-O films

#225
20050128683
2005-06-16

Dielectric ceramic composition and method of production and electronic device of the same

#226
20050109263
2005-05-26

Electromechanical actuators

#227
20050095851
2005-05-05

Method of production of multilayer ceramic electronic device

#228
20050009686
2005-01-13

Ceramic heat exchanger

#229
18352264
2024-01-02

Low-temperature sintered microwave dielectric ceramic material and preparation method thereof

#230
16158847
2019-12-24

Multilayer ceramic capacitor with dielectric layers including dielectric grains having a core-shell structure